Skip to main content

The potassium paradox: Implications for soil fertility, crop production and human health

  • S.A. Khan (a1), R.L. Mulvaney (a1) and T.R. Ellsworth (a1)

Intensive fertilizer usage of KCl has been inculcated as a prerequisite for maximizing crop yield and quality, and relies on a soil test for exchangeable K in the plow layer to ensure that soil productivity will not be limited by nutrient depletion. The interpretive value of this soil test was rigorously evaluated by: (1) field sampling to quantify biweekly changes and seasonal trends, (2) characterizing the variability induced by air drying and the dynamic nature of soil K reserves and (3) calculating the K balance in numerous cropping experiments. These evaluations leave no alternative but to question the practical utility of soil K testing because test values cannot account for the highly dynamic interchange between exchangeable and non-exchangeable K, exhibit serious temporal instability with or without air drying and do not differentiate soil K buildup from depletion. The need for routine K fertilization should also be questioned, considering the magnitude and inorganic occurrence of profile reserves, the recycling of K in crop residues and the preferential nature of K uptake. An extensive survey of more than 2100 yield response trials confirmed that KCl fertilization is unlikely to increase crop yield. Contrary to the inculcated perception of KCl as a qualitative commodity, more than 1400 field trials predominately documented a detrimental effect of this fertilizer on the quality of major food, feed and fiber crops, with serious implications for soil productivity and human health.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the or variations. ‘’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      The potassium paradox: Implications for soil fertility, crop production and human health
      Available formats
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      The potassium paradox: Implications for soil fertility, crop production and human health
      Available formats
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      The potassium paradox: Implications for soil fertility, crop production and human health
      Available formats
The online version of this article is published within an Open Access environment subject to the conditions of the Creative Commons Attribution-NonCommercial-ShareAlike licence . The written permission of Cambridge University Press must be obtained for commercial re-use.
Corresponding author
* Corresponding author:
Hide All
1 Howard, A. 1947. The Soil and Health. A Study of Organic Agriculture. Devin-Adair, New York.
2 Snow, J.S. 2009. Misunderstanding Soil Ecosystems. MA thesis, Tufts University, Boston, MA. Available at Web site (verified November 27, 2012).
3 Visser, J. 2010. Down to Earth. PhD thesis, Wageningen University, Wageningen, The Netherlands. Available at Web site (verified November 27, 2012).
4 Truog, E. 1938. Putting soil science to work. Journal of the American Society of Agronomy 30:973985.
5 Liebhardt, W.C. and Cotnoir, L. 1979. Potassium fertilizer recommendations and changes in potassium soil test values as influenced by additions of potassium. Communications in Soil Science and Plant Analysis 10:831840.
6 Olson, R.A., Anderson, F.N., Frank, K.D., Grabouski, P.H., Rehm, G.W., and Shapiro, C.A. 1987. Soil testing interpretations: Sufficiency vs. build-up and maintenance. In Brown, J.R. (ed.). Soil Testing: Sampling, Correlation, Calibration, and Interpretation. Soil Science Society of America, Madison, WI. p. 4152.
7 Thomas, G.W. 1989. The soil bank account and the farmer's bank account. Journal of Production Agriculture 2:122124.
8 Hopkins, C.G. and Aumer, J.P. 1915. Potassium from the Soil. Illinois Agricultural Experiment Station Bulletin 182. University of Illinois, Urbana, IL.
9 Blair, A.W. 1919. Utilizing soil potash by means of intermediary crops. Proceedings of the Society for Promotion of Agricultural Science 39:6974.
10 Reitemeier, R.F. 1951. Soil potassium. Advances in Agronomy 3:113164.
11 Srinivasa Rao, C., Rupa, T.R., Rao, A.S., and Bansal, S.K. 2001. Subsoil potassium availability in twenty-two benchmark soil series of India. Communications in Soil Science and Plant Analysis 32:863876.
12 Bradfield, R. 1946. Where are the new discoveries in soil science leading? I. The physical chemistry of soil–plant relationships. Soil Science Society of America Proceedings 11:38.
13 Bray, R.H. 1944. Soil-plant relations I. The quantitative relation of exchangeable potassium to crop yields and to crop response to potash additions. Soil Science 58:305324.
14 Bear, F.E. and Toth, S.J. 1948. Influence of calcium on availability of other soil cations. Soil Science 65:6974.
15 Eckert, D.J. 1987. Soil test interpretations: Basic cation saturation ratios and sufficiency levels. . In Brown, J.R. (ed.). Soil Testing: Sampling, Correlation, Calibration, and Interpretation. Soil Science Society of America, Madison, WI. p. 5364.
16 Kopittke, P.M. and Menzies, N.W. 2007. A review of the use of the basic cation saturation ratio and the ‘ideal’ soil. Soil Science Society of America Journal 71:259265.
17 Bray, R.H. and DeTurk, E.E. 1938. The release of potassium from non-replaceable forms in Illinois soils. Soil Science Society of America Proceedings 3:101106.
18 Luebs, R.E., Stanford, G., and Scott, A.D. 1956. Relation of available potassium to soil moisture. Soil Science Society of America Proceedings 20:4550.
19 Martin, H.W. and Sparks, D.L. 1985. On the behavior of nonexchangeable potassium in soils. Communications in Soil Science and Plant Analysis 16:133162.
20 Mengel, K. and Uhlenbecker, K. 1993. Determination of available interlayer potassium and its uptake by ryegrass. Soil Science Society of America Journal 57:761766.
21 Skogley, E.O. 1994. Reinventing soil testing for the future. In Havlin, J.L. and Jacobsen, J.S. (eds). Soil Testing: Prospects for Improving Nutrient Recommendations. Soil Science Society of America Special Publication 40. Soil Science Society of America, Madison, WI. p. 187201.
22 Khan, S.A. 1991. Soil K level in relation to K treatment, season of year and soil moisture level. PhD thesis, University of Illinois, Urbana, IL.
23 Wascher, H.L., Alexander, J.D., Ray, B.W., Beavers, A.H., and Odell, R.T. 1960. Characteristics of Soils Associated with Glacial Tills in Northeastern Illinois. Illinois Agricultural Experiment Station Bulletin 665. University of Illinois, Urbana, IL.
24 Knudsen, D., Peterson, G.A., and Pratt, P.F. 1982. Lithium, sodium, and potassium. In Page, A.L., Miller, R.H., and Keeney, D.R. (eds). Methods of Soil Analysis. Part 2. Chemical and Microbiological Properties. Agronomy Monograph 9. 2nd ed. American Society of Agronomy and Soil Science Society of America, Madison, WI. p. 225246.
25 Suhr, N.H. and Ingamells, C.O. 1966. Solution technique for analysis of silicates. Analytical Chemistry 38:730734.
26 Velde, B. and Peck, T. 2002. Clay mineral changes in the Morrow experimental plots, University of Illinois. Clays and Clay Minerals 50:364370.
27 Khan, S.A., Mulvaney, R.L., Ellsworth, T.R., and Boast, C.W. 2007. The myth of nitrogen fertilization for soil carbon sequestration. Journal of Environmental Quality 36:18211832.
28 Fernández, F.G. and Hoeft, R.G. 2009. Managing soil pH and crop nutrients. In Nafziger, E. (ed.) Illinois Agronomy Handbook. 24th ed. University of Illinois, Urbana, IL. p. 91112.
29 Leask, W.C. and Daynard, T.B. 1973. Dry matter yield, in vitro digestibility, percent protein, and moisture of corn stover following grain maturity. Canadian Journal of Plant Science 53:515522.
30 Kiniry, J.R., Williams, J.R., Vanderlip, R.L., Atwood, J.D., Reicosky, D.C., Mulliken, J., Cox, W.J., Mascagni, H.J. Jr, Hollinger, S.E., and Wiebold, W.J. 1997. Evaluation of two maize models for nine U.S. locations. Agronomy Journal 89:421426.
31 Prince, S.D., Haskett, J., Steininger, M., Strand, H., and Wright, R. 2001. Net primary production of U.S. Midwest croplands from agricultural harvest yield data. Ecological Applications 11:11941205.
32 Tollenaar, M., Ahmadzadeh, A., and Lee, E.A. 2004. Physiological basis of heterosis for grain yield in maize. Crop Science 44:20862094.
33 Mengel, K. 2007. Potassium. In Barker, A.V. and Pilbeam, D.J. (eds). Handbook of Plant Nutrition. Taylor & Francis, Boca Raton, FL. p. 91120.
34 Lovell, M.C. 2012. Seasonal adjustment of economic time series and multiple regression analysis. Journal of the American Statistical Association 58:9931010.
35 SAS Institute. 2013. SAS Onlinedoc 9.1.3. SAS Institute, Cary, NC. Available at Web site (verified March 21, 2013).
36 Hochberg, Y. 1988. A sharper Bonferroni procedure for multiple tests of significance. Biometrika 75:800802.
37 Attoe, O.J. 1946. Potassium fixation and release in soils occurring under moist and drying conditions. Soil Science Society of America Proceedings 11:145149.
38 Hanway, J.J., Barber, S.A., Bray, R.H., Caldwell, A.C., Fried, M., Kurtz, L.T., Lawton, K., Pesek, J.T., Pretty, K., Reed, M., and Smith, F.W. 1962. North Central Regional Potassium Studies III. Field Studies with Corn. Iowa Agricultural Experiment Station Research Bulletin 503. Iowa State University, Ames, IA.
39 Hoskinson, R.L., Hess, J.R., and Alessi, R.S. 1999. Temporal changes in the spatial variability of soil nutrients. In Stafford, J.V. (ed.). Precision Agriculture ‘99. Part 1. Academic Press, Sheffield, England. p. 6170.
40 Blakemore, M. 1966. Seasonal changes in the amounts of phosphorus and potassium dissolved from soils by dilute calcium chloride solutions. Journal of Agricultural Science, Cambridge 66:139146.
41 Childs, F.D. and Jencks, E.M. 1967. Effect of time and depth of sampling upon soil test results. Agronomy Journal 59:537540.
42 International Plant Nutrition Institute. 2009. Soil Fertility Shifts in Eastern Canada and the Northeastern USA. International Plant Nutrition Institute, Norcross, GA. Available at Web site (verified May 25, 2012).
43 Fixen, P.E. 2006. Soil test levels in North America. Better Crops 90(1):47. Available at Web site$FILE/Better%20Crops%202006-1%20(lo%20res).pdf (verified August 13, 2012).
44 Cope, J.T. Jr 1970. Response of Cotton, Corn, Bermudagrass to Rates of N, P, and K. Alabama Agricultural Experiment Station Circular 181. Auburn University, Auburn, AL.
45 Cope, J.T. Jr 1981. Effects of 50 years of fertilization with phosphorus and potassium on soil test levels and yields at six locations. Soil Science Society of America Journal 45:342347.
46 Cope, J.T. Jr 1984. Long-Term Fertility Experiments on Cotton, Corn, Soybeans, Sorghum, and Peanuts, 1929–1982. Alabama Agricultural Experiment Station Bulletin 561. Auburn University, Auburn, AL.
47 Mainz, M.A. 1987. Potassium rate study. In Report of Research Results, Northwestern Illinois Agricultural Research and Demonstration Center. University of Illinois, Urbana, IL. p. 4548.
48 Ebelhar, S.A. and Varsa, E.C. 1999. Tillage and potassium placement effects on potassium use efficiency in a corn–soybean rotation. In Hoeft, R.G. (ed.). 1999 Illinois Fertilizer Conference Proceedings. University of Illinois, Urbana, IL. p. 161180. Available at Web site (verified August 9, 2012).
49 Li, R.-G. and Barber, S.A. 1988. Effect of phosphorus and potassium fertilizer on crop response and soil fertility in a long-term experiment. Fertilizer Research 15:123136.
50 Mallarino, A.P., Webb, J.R., and Blackmer, A.M. 1991. Soil test values and grain yields during 14 years of potassium fertilization of corn and soybean. Journal of Production Agriculture 4:562566.
51 Mallarino, A.P., Webb, J.R., and Blackmer, A.M. 1991. Corn and soybean yields during 11 years of phosphorus and potassium fertilization on a high-testing soil. Journal of Production Agriculture 4:312317.
52 Vitosh, M.L., Lucas, R.E., and Silva, G.H. 1997. Long-term effects of fertilizer and manure on corn yield, soil carbon, and other soil chemical properties in Michigan. In Paul, E.A., Paustian, K.A., Elliott, E.T. and Cole, C.V. (eds). Soil Organic Matter in Temperate Agroecosystems: Long-Term Experiments in North America. CRC Press, Boca Raton, FL. p. 129139.
53 Randall, G.W., Evans, S.D., and Iragavarapu, T.K. 1997. Long-term P and K applications. II. Effect on corn and soybean yields and plant P and K concentrations. Journal of Production Agriculture 10:572580.
54 Randall, G.W., Iragavarapu, T.K., and Evans, S.D. 1997. Long-term P and K applications: I. Effect on soil test incline and decline rates and critical soil test levels. Journal of Production Agriculture 10:565571.
55 Brown, J.R., Osburn, D.D., Redhage, D., and Gantzer, C.J. 1995. Multi-crop comparisons on Sanborn Fields, Missouri, USA. In Barnett, V., Payne, R. and Steiner, R. (eds). Agricultural Sustainability. Economic, Environmental and Statistical Considerations. John Wiley, Chichester, England. p. 111132.
56 Olson, R.A., Frank, K.D., Grabouski, P.H., and Rehm, G.W. 1982. Economic and agronomic impacts of varied philosophies of soil testing. Agronomy Journal 74:492499.
57 Markus, D.K. and Battle, W.R. 1965. Soil and plant responses to long-term fertilization of alfalfa (Medicago sativa L.). Agronomy Journal 57:613616.
58 Woodhouse, W.W. Jr 1968. Long-term fertility requirements of coastal bermudagrass. I. Potassium. Agronomy Journal 60:508512.
59 Davis, R.L., Patton, J.J., Teal, R.K., Tang, Y., Humphreys, M.T., Mosali, J., Girma, K., Lawles, J.W., Moges, S.M., Malapati, A., Si, J., Zhang, H., Deng, S., Johnson, G.V., Mullen, R.W., and Raun, W.R. 2003. Nitrogen balance in the Magruder Plots following 109 years in continuous winter wheat. Journal of Plant Nutrition 26:15611580.
60 Girma, K., Holtz, S.L., Arnall, D.B., Tubaña, B.S., and Raun, W.R. 2007. The Magruder Plots: Untangling the puzzle. Agronomy Journal 99:11911198.
61 Harper, H.J. 1959. 65 Years of Continuous Wheat. Bulletin B-531. Oklahoma State University, Stillwater, OK.
62 Lutz, J.A. Jr 1973. Potassium supplying power of Groseclose silt loam for corn. Communications in Soil Science and Plant Analysis 4:2330.
63 Zhang, H., Wang, B., and Xu, M. 2008. Effects of inorganic fertilizer inputs on grain yields and soil properties in a long-term wheat-corn cropping system in south China. Communications in Soil Science and Plant Analysis 39:15831599.
64 Zhang, H.-M., Wang, B.-R., Xu, M.-G., and Fan, T.-L. 2009. Crop yield and soil responses to long-term fertilization on a red soil in southern China. Pedosphere 19:199207.
65 Wang, X., Hoogmoed, W.B., Cai, D., Perdok, U.D., and Oenema, O. 2007. Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: II Nutrient balances and soil fertility. Nutrient Cycling in Agroecosystems 79:1734.
66 Wang, X., Cai, D., Hoogmoed, W.B., Perdok, U.D., and Oenema, O. 2007. Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: I Grain yields and nutrient use efficiencies. Nutrient Cycling in Agroecosystems 79:116.
67 Johnston, A.E. and Poulton, P.R. 1977. Yields on the Exhaustion Land and changes in the NPK content of the soils due to cropping and manuring, 1852–1975. In Rothamsted Experimental Station Report for 1976. Part 2. Lawes Agricultural Trust, Harpenden, Herts, England. p. 5385.
68 Last, P.J., Webb, D.J., Bugg, R.B., Bean, K.M.R., Durrant, M.J., and Jaggard, K.W. 1985. Long-term effects of fertilizers at Broom's Barn, 1965–82. In Rothamsted Experimental Station Report for 1984. Part 2. Lawes Agricultural Trust, Harpenden, Herts, England. p. 231249.
69 Blake, L., Mercik, S., Koerschens, M., Goulding, K.W.T., Stempen, S., Weigel, A., Poulton, P.R., and Powlson, D.S. 1999. Potassium content in soil, uptake in plants and the potassium balance in three European long-term field experiments. Plant and Soil 216:114.
70 Dam Kofoed, A. and Nemming, O. 1976. Askov 1894: Fertilizers and manure on sandy and loamy soils. Annales Agronomiques 27:583610.
71 Amberger, A. and Gutser, R. 1976. Effect of long-term potassium fertilization on crops and potassium dynamics of a brown earth (Weihenstephan). Annales Agronomiques 27:643657.
72 Stumpe, H., Garz, J., Johannemann, R., and Buchte, M. 1989. Einfluß der K-Düngung auf den Ertrag und einige Bodeneigenschaften in einem Dauerversuch auf einer Sandlöß-Braunschwarzerde in Halle. Archiv für Acker- und Pflanzenbau und Bodenkunde 33:301310.
73 Brar, B.S. and Pasricha, N.S. 1998. Long-term studies on integrated use of organic and inorganic fertilizers in maize-wheat-cowpea cropping system on alluvial soil of Punjab. In Swarup, A., Damodar Reddy, D., and Prasad, R.N. (eds). Proceedings of a National Workshop on Long-term Soil Fertility Management Integrated Plant Nutrient Supply. Indian Institute of Soil Science, Bhopal, India. p. 154168.
74 Sharma, S.P., Sharma, J., and Subehia, S.K. 1998. Long-term effects of chemical fertilizers on crop yields, nutrients uptake and soil environment in western Himalayan soils. In Swarup, A., Damodar Reddy, D., and Prasad, R.N. (eds). Proceedings of a National Workshop on Long-term Soil Fertility Management Integrated Plant Nutrient Supply. Indian Institute of Soil Science, Bhopal, India. p. 125138.
75 Lee, R. and Metson, A.J. 1977. Potassium removal from soil by lucerne over three years and the effect of potassium topdressing. New Zealand Journal of Agricultural Research 20:185192.
76 Agboola, A.A. 1970. Preliminary investigation on the effect of continuous cropping of maize on grain yield and on total nitrogen, available phosphorus and exchangeable potassium on three Nigerian soils. Nigerian Journal of Science 4:8999.
77 De Datta, S.K., Gomez, K.A., and Descalsota, J.P. 1988. Changes in yield response to major nutrients and in soil fertility under intensive rice cropping. Soil Science 146:350358.
78 Öborn, I., Edwards, A.C., and Hillier, S. 2010. Quantifying uptake rate of potassium from soil in a long-term grass rotation experiment. Plant and Soil 335:319.
79 Tisdale, S.L., Nelson, W.L., and Beaton, J.D. 1985. Soil Fertility and Fertilizers. 4th ed. Macmillan Publishing Company, New York, NY.
80 Cassman, K.G., Olk, D.C., Brouder, S.M., and Roberts, B.A. 1995. The influence of moisture regime, organic matter, and root eco-physiology on the availability and acquisition of potassium: Implications for tropical lowland rice. In Potassium in Asia. Balanced Fertilization to Increase and Sustain Agricultural Production. International Potash Institute, Basel, Switzerland. p. 135156.
81 Abel, F.A.E. and Magistad, O.C. 1935. Conversion of soil potash from the non-replaceable to the replaceable form. Journal of the American Society of Agronomy 27:437445.
82 Parker, D.R., Hendricks, G.J., and Sparks, D.L. 1989. Potassium in Atlantic Coastal Plain soils: II. Crop responses and changes in soil potassium under intensive management. Soil Science Society of America Journal 53:397401.
83 Mengel, K., Rahmatullah, , and Dou, H. 1998. Release of potassium from the silt and sand fraction of loess-derived soils. Soil Science 163:805813.
84 Rouse, R.D. and Bertramson, B.R. 1949. Potassium availability in several Indiana soils: Its nature and methods of evaluation. Soil Science Society of America Proceedings 14:113123.
85 Wood, L.K. and DeTurk, E.E. 1941. The absorption of potassium in soils in non-replaceable forms. Soil Science Society of America Proceedings 5:152161.
86 Oliveira, V., Ludwick, A.E., and Beatty, M.T. 1971. Potassium removed from some southern Brazilian soils by exhaustive cropping and chemical extraction methods. Soil Science Society of America Proceedings 35:763767.
87 Ganeshamurthy, A.N. 1983. An estimate of the uptake of subsurface soil potassium by crops in two long-term experiments. Journal of Agricultural Science, Cambridge 101:495497.
88 Badraoui, M., Bloom, P.R., and Delmaki, A. 1992. Mobilization of non-exchangeable K by ryegrass in five Moroccan soils with and without mica. Plant and Soil 140:5563.
89 Zubillaga, M.M. and Conti, M.E. 1996. Availability of exchangeable and non-exchangeable K in Argentine soils with different mineralogy. Zeitschrift für Pflanzenernährung und Bodenkunde 159:149153.
90 Mortland, M.M., Lawton, K., and Uehara, G. 1958. Fixation and release of potassium by some clay minerals. Soil Science Society of America Proceedings 21:381384.
91 Hinsinger, P.H., Dufey, J.E., and Jaillard, B. 1991. Biological weathering of micas in the rhizosphere as related to potassium absorption by plant roots. In McMichael, B.L. and Persson, H. (eds) Plant Roots and Their Environment. Elsevier, Amsterdam, The Netherlands. p. 98105.
92 Hoffland, E., Kuyper, T.W., Wallander, H., Plassard, C., Gorbushina, A.A., Haselwandter, K., Holmström, S., Landeweert, R., Lundström, U.S., Rosling, A., Sen, R., Smits, M.M., van Hees, P.A.W., and van Breemen, N. 2004. The role of fungi in weathering. Frontiers in Ecology and the Environment 2:258264.
93 van Schöll, L., Kuyper, T.W., Smits, M.M., Landeweert, R., Hoffland, E., and van Breemen, N. 2008. Rock-eating mycorrhizas: Their role in plant nutrition and biogeochemical cycles. Plant and Soil 303:3547.
94 Arocena, J.M., Velde, B., and Robertson, S.J. 2012. Weathering of biotite in the presence of arbuscular mycorrhizae in selected agricultural crops. Applied Clay Science 64:1217.
95 Yuan, T.L., Zelazny, L.W., and Ratanaprasatporn, A. 1976. Potassium status of selected Paleudults in the Lower Coastal Plain. Soil Science Society of America Journal 40:229233.
96 Sparks, D.L., Martens, D.C., and Zelazny, L.W. 1980. Plant uptake and leaching of applied and indigenous potassium in Dothan soils. Agronomy Journal 72:551555.
97 Woodruff, J.R. and Parks, C.L. 1980. Topsoil and subsoil potassium calibration with leaf potassium for fertility rating. Agronomy Journal 72:392396.
98 Bray, R.H. 1940. The chemical nature of soil potassium in relation to its availability in Illinois soils. PhD thesis, University of Illinois, Urbana, IL.
99 Kuhlmann, H., Claassen, N., and Wehrmann, J. 1985. A method for determining the K-uptake from subsoil by plants. Plant and Soil 83:449452.
100 Kuhlmann, H. 1990. Importance of the subsoil for the K nutrition of crops. Plant and Soil 127:129136.
101 Witter, E. and Johansson, G. 2001. Potassium uptake from the subsoil by green manure crops. Biological Agriculture and Horticulture 19:127141.
102 Jouany, C., Colomb, B., and Bosc, M. 1996. Long-term effects of potassium fertilization on yields and fertility status of calcareous soils of south-west France. European Journal of Agronomy 5:287294.
103 Grimes, D.W. and Hanway, J.J. 1967. An evaluation of the availability of K in crop residues. Soil Science Society of America Proceedings 31:705706.
104 Borisova, N.I., Vasineva, L.V., and Semenov, Y.I. 1984. Use of potassium from straw and green mass of barley, labelled with 40K, by plants. Soviet Agricultural Science 12:2830.
105 Dierolf, T.S. and Yost, R.S. 2000. Stover and potassium management in an upland rice–soybean rotation on an Indonesian Ultisol. Agronomy Journal 92:106114.
106 Rosolem, C.A., Calonego, J.C., and Foloni, J.S.S. 2005. Potassium leaching from millet straw as affected by rainfall and potassium rates. Communications in Soil Science and Plant Analysis 36:10631074.
107 Glass, A.D.M. 1983. Regulation of ion transport. Annual Review of Plant Physiology 34:311326.
108 Saha, M.N., Chaudhury, J., Saha, A.R., and Ray, P.K. 1998. Effect of intensive cropping and fertilizer use on soil properties and crop yields in a long-term experiment. In Swarup, A., Damodar Reddy, D. and Prasad, R.N. (eds). Proceedings of a National Workshop on Long-term Soil Fertility Management Integrated Plant Nutrient Supply. Indian Institute of Soil Science, Bhopal, India. p. 215220.
109 Walker, M.E., Flowers, R.A., Henning, R.J., Keisling, T.C., and Mullinix, B.G. 1979. Response of early bunch peanuts to calcium and potassium fertilization. Peanut Science 6:119123.
110 Hartzog, D.L. and Adams, J.F. 1988. Relationship between soil-test P and K and yield response of runner peanuts to fertilizer. Communications in Soil Science and Plant Analysis 19:16451653.
111 Roberts, S. and Beaton, J.D. 1988. Potato Use of Phosphorus and Potassium in Sandy Soils. Research Bulletin XB1004. Washington State University, Pullman, WA.
112 Davenport, J.R. and Bentley, E.M. 2001. Does potassium fertilizer form, source, and time of application influence potato yield and quality in the Columbia Basin? American Journal of Potato Research 78:311318.
113 Bailey, L.D. 1983. Effects of potassium fertilizer and fall harvests on alfalfa grown on the eastern Canadian prairies. Canadian Journal of Soil Science 63:211219.
114 Rowberry, R.G. and Ketcheson, J.W. 1978. Sources of potassium in potato fertilizer and times of application. Canadian Journal of Plant Science 58:779782.
115 Terman, G.L. 1977. Yields and nutrient accumulation by determinate soybeans, as affected by applied nutrients. Agronomy Journal 69:234238.
116 Burmester, C.H. and Adams, F. 1983. Fertilizer requirements for new plantings of tall fescue and white clover on two low-fertility Ultisols. Agronomy Journal 75:936940.
117 Laughlin, W.M., Martin, P.F., and Smith, G.R. 1973. Potassium rate and source influences on yield and composition of bromegrass forage. Agronomy Journal 65:8587.
118 Bhangoo, M.S. and Albritton, D.J. 1972. Effect of fertilizer nitrogen, phosphorus, and potassium on yield and nutrient content of Lee soybeans. Agronomy Journal 64:743746.
119 Maples, R. and Keogh, J.L. 1974. Fertilization of Cotton with Potassium, Magnesium, and Sulfur on Certain Delta Soils: Alfisols Formed from Mississippi River Valley Alluvium. Arkansas Agricultural Experiment Station Bulletin 787. University of Arkansas, Fayetteville, AR.
120 Rupe, J.C., Widick, J.D., Sabbe, W.E., Robbins, R.T., and Becton, C.B. 2000. Effect of chloride and soybean cultivar on yield and the development of sudden death syndrome, soybean cyst nematode, and southern blight. Plant Disease 84:669674.
121 Cassman, K.G., Kerby, T.A., Roberts, B.A., Bryant, D.C., and Brouder, S.M. 1989. Differential response of two cotton cultivars to fertilizer and soil potassium. Agronomy Journal 81:870876.
122 Linquist, B.A., Byous, E., Jones, G., Williams, J.F., Six, J., Horwath, W., and van Kessel, C. 2008. Nitrogen and potassium fertility impacts on aggregate sheath spot disease and yields of rice. Plant Production Science 11:260267.
123 Barbarick, K.A. 1985. Potassium fertilization of alfalfa grown on a soil high in potassium. Agronomy Journal 77:442445.
124 Allinson, D.W., Guillard, K., Rafey, M.M., Grabber, J.H., and Dest, W.M. 1992. Response of reed canarygrass to nitrogen and potassium fertilization. Journal of Production Agriculture 5:595601.
125 Svec, L.V., Andrews, A.K., and Crittenden, H.W. 1976. Soybean (Glycine max (L.) Merr.) yield and disease incidence with potassium fertilization. Communications in Soil Science and Plant Analysis 7:727741.
126 Sartain, J.B., Forbes, R.B., and Usherwood, N.R. 1979. Yield response of soybeans to P and K fertilization as correlated with soil extractable and tissue nutritional levels. Communications in Soil Science and Plant Analysis 10:12191232.
127 Elwali, A.M.O. and Gascho, G.J. 1983. Sugarcane response to P, K, and DRIS corrective treatments on Florida Histosols. Agronomy Journal 75:7983.
128 Obreza, T.A. and Rhoads, F.M. 1988. Irrigated corn response to soil-test indices and fertilizer nitrogen, phosphorous, potassium, and magnesium. Soil Science Society of America Journal 52:701706.
129 Welch, L.F., Adams, W.E., and Carmon, J.L. 1963. Yield response surfaces, isoquants, and economic fertilizer optima for coastal bermudagrass. Agronomy Journal 55:6367.
130 Walker, M.E., Morris, H.D., and Carter, R.L. 1974. The Effect of Rate and Method of Application of N, P, and K on Yield, Quality and Chemical Composition of Spanish and Runner Peanuts. Georgia Agricultural Experiment Station Research Bulletin 152. University of Georgia, Athens, GA.
131 Parker, M.B., Gascho, G.J., and Gaines, T.P. 1983. Chloride toxicity of soybeans grown on Atlantic Coast Flatwoods soils. Agronomy Journal 75:439443.
132 Walker, M.E., Gaines, T.P., and Parker, M.B. 1989. Potassium, magnesium, and irrigation effects on peanuts grown on two soils. Communications in Soil Science and Plant Analysis 20:10111032.
133 McDole, R.E., Stallknecht, G.F., Dwelle, R.B., and Pavek, J.J. 1978. Response of four potato varieties to potassium fertilization in a seed growing area of eastern Idaho. American Potato Journal 55:495504.
134 Welch, L.F., Johnson, P.E., McKibben, G.E., Boone, L.V., and Pendleton, J.W. 1966. Relative efficiency of broadcast versus banded potassium for corn. Agronomy Journal 58:618621.
135 Stivers, R.K. and Ohlrogge, A.J. 1952. Influence of phosphorus and potassium fertilization of two soil types on alfalfa yield, stand, and content of these elements. Agronomy Journal 44:618621.
136 Hanway, J.J., Barber, S.A., Bray, R.H., Caldwell, A.C., Engelbert, L.E., Fox, R.L., Fried, M., Hovland, D., Ketcheson, J.W., Laughlin, W.M., Lawton, K., Lipps, R.C., Olson, R.A., Pesek, J.T., Pretty, K., Smith, F.W., and Stickney, E.M. 1961. North Central Regional Potassium Studies. I. Field Studies with Alfalfa. Iowa Agricultural Experiment Station Research Bulletin 494. Iowa State University, Ames, IA.
137 Sweeney, D.W., Moyer, J.L., Jardine, D.J., and Whitney, D.A. 2011. Nitrogen, phosphorus, and potassium effects on grain sorghum production and stalk rot following alfalfa and birdsfoot trefoil. Journal of Plant Nutrition 34:13301340.
138 Templeton, W.C. Jr and Taylor, T.H. 1966. Yield response of a tall fescue-white clover sward to fertilization with nitrogen, phosphorus, and potassium. Agronomy Journal 58:319322.
139 Gascho, G.J., Davis, J.F., Fogg, R.A., and Frakes, M.G. 1969. The effects of potassium carriers and levels of potassium and nitrogen fertilization on the yield and quality of sugar beets. Journal of the American Society of Sugar Beet Technologists 15:298305.
140 Grissom, P. and Spurgeon, W.I. 1961. Fertility Practices for Cotton and Corn in the Yazoo-Mississippi Delta. Mississippi State University Agricultural Experiment Station Bulletin 614. Mississippi State University, State College, MS.
141 Pettigrew, W.T. 1999. Potassium deficiency increases specific leaf weights and leaf glucose levels in field-grown cotton. Agronomy Journal 91:962968.
142 Adeli, A. and Varco, J.J. 2002. Potassium management effects on cotton yield, nutrition, and soil potassium level. Communications in Soil Science and Plant Analysis 25:22292242.
143 Pettigrew, W.T. 2003. Relationships between insufficient potassium and crop maturity in cotton. Agronomy Journal 95:13231329.
144 Wortmann, C.S., Dobermann, A.R., Ferguson, R.B., Hergert, G.W., Shapiro, C.A., Tarkalson, D.D., and Walters, D.T. 2009. High-yielding corn response to applied phosphorus, potassium, and sulfur in Nebraska. Agronomy Journal 101:546555.
145 Malm, N.R. 1972. Fertilization of Established Alfalfa with Nitrogen and Potassium. New Mexico Agricultural Experiment Station Research Report 240. New Mexico State University, Las Cruces, NM.
146 Nelson, W.L., Burkhart, L., and Colwell, W.E. 1945. Fruit development, seed quality, chemical composition, and yield of soybeans as affected by potassium and magnesium. Soil Science Society of America Proceedings 10:224229.
147 Goos, R.J., Johnson, B.E., and Holmes, B.M. 1987. Effect of potassium chloride fertilization on two barley cultivars differing in common root rot reaction. Canadian Journal of Plant Science 67:395401.
148 Lueking, M.A., Johnson, J.W., and Himes, F.L. 1983. Effects of increasing the rates of potassium and nitrapyrin on nitrogen uptake by corn. Agronomy Journal 75:247249.
149 Hudak, C., Stehouwer, R., and Johnson, J. 1989. An evaluation of K rate, placement and tillage systems for soybeans. Journal of Fertilizer Issues 6:2531.
150 Robinson, R.R., Rhykerd, C.L., and Gross, C.F. 1962. Potassium uptake by orchardgrass as affected by time, frequency and rate of potassium fertilization. Agronomy Journal 54:351353.
151 Alva, A.K. 1985. A comparison of fertilizer recommendations by soil testing program and alfalfa yield response in soils of two associations. Communications in Soil Science and Plant Analysis 16:213228.
152 Gaspar, P.E., Reeves, D.L., Schumacher, T.E., and Fixen, P.E. 1994. Oat cultivar response to potassium chloride on soils testing high in potassium. Agronomy Journal 86:255258.
153 Wittels, H. and Seatz, L.F. 1953. Effect of potash fertilization on yield, stalk breakage and mineral composition of corn. Soil Science Society of America Proceedings 17:369371.
154 Clement-Bailey, J. and Gwathmey, C.O. 2007. Potassium effects on partitioning, yield, and earliness of contrasting cotton cultivars. Agronomy Journal 99:11301136.
155 Nelson, L.R., Keisling, T.C., and Rouquette, F.M. Jr 1983. Potassium rates and sources for coastal bermudagrass. Soil Science Society of America Journal 47:963966.
156 Westermann, D.T., Tindall, T.A., James, D.W., and Hurst, R.L. 1994. Nitrogen and potassium fertilization of potatoes: Yield and specific gravity. American Potato Journal 71:417431.
157 Camper, H.M. and Lutz, J.A. Jr 1977. Plowsole placement of fertilizer for soybeans and response to tillage of plowsole. Agronomy Journal 69:701704.
158 Jones, G.D., Lutz, J.A. Jr, and Smith, T.J. 1977. Effects of phosphorus and potassium on soybean nodules and seed yield. Agronomy Journal 69:10031006.
159 Smith, D. 1975. Effects of potassium topdressing a low fertility silt loam soil on alfalfa herbage yields and composition and on soil K values. Agronomy Journal 67:6064.
160 Rominger, R.S., Smith, D., and Peterson, L.A. 1976. Yield and chemical composition of alfalfa as influenced by high rates of K topdressed as KCl and K2SO4 . Agronomy Journal 68:573577.
161 Smith, D. and Smith, R.R. 1977. Responses of red clover to increasing rates of topdressed potassium fertilizer. Agronomy Journal 69:4548.
162 Smith, D. and Powell, R.D. 1979. Yield of alfalfa as influenced by levels of P and K fertilization. Communications in Soil Science and Plant Analysis 10:531543.
163 Panique, E., Kelling, K.A., Schulte, E.E., Hero, D.E., Stevenson, W.R., and James, R.V. 1997. Potassium rate and source effects on potato yield, quality, and disease interaction. American Potato Journal 74:379398.
164 Fageria, N.K., Wright, R.J., Baligar, V.C., and Carvalho, J.R.P. 1990. Upland rice response to potassium fertilization on a Brazilian Oxisol. Fertilizer Research 21:141147.
165 Rosolem, C.A. and Nakagawa, J. 2001. Residual and annual potassic fertilization for soybeans. Nutrient Cycling in Agroecosystems 59:143149.
166 Cox, F.R. and Uribe, E. 1992. Management and dynamics of potassium in a humid tropical Ultisol under a rice–cowpea rotation. Agronomy Journal 84:655660.
167 Casanova, E. 2000. Phosphorus and potassium fertilization and mineral nutrition of soybean. Interciencia 25:9295.
168 Jekić, M., Trpeski, V., and Raimi, N. 1998. The effect of KCl and K2SO4 in NPK fertilizers on yield, quality and economical earning by production of potato on alluvium of the Vardar. Macedonian Agricultural Review 45:1115.
169 Gaydou, E.M. and Arrivets, J. 1983. Effects of phosphorus, potassium, dolomite, and nitrogen fertilization on the quality of soybean. Yields, proteins, and lipids. Journal of Agricultural and Food Chemistry 31:765769.
170 Lombin, G. and Mustafa, S. 1981. Potassium response of cotton on some Inceptisols and Oxisols of northern Nigeria. Agronomy Journal 73:724729.
171 Lombin, G. and Singh, L. 1986. Fertilizer responses of groundnuts (Arachis hypogae L.) under continuous intensive cultivation in the Nigerian savannah. Fertilizer Research 10:4358.
172 Rahman, M.A., Chakravarty, D., Shahidullah, M., and Hossain, M.T. 1978. Studies on the effect of nitrogen phosphorus and potassium on the growth, yield and nutrient contents of safflower (Carthamus tinctorius L.). Bangladesh Journal of Scientific and Industrial Research 13:3239.
173 Chowdhury, M.K.A. and Rahman, M.H. 1990. Potash requirement of sugarcane in Gangetic River flood plain soils of Bangladesh. Journal of the Indian Society of Soil Science 38:688691.
174 Bokhtiar, S.M., Karim, A.J.M.S., Hossain, K.M., Hossain, T., and Egashira, K. 2001. Response of radish to varying levels of irrigation water and fertilizer potassium on clay terrace soil of Bangladesh. Communications in Soil Science and Plant Analysis 32:29792991.
175 Hymowitz, T., Jethmalani, S.C., Tiwari, K.L., and Walker, W.M. 1971. Effect of inoculum, variety, nitrogen, phosphorus, and potassium on yield, protein and oil content of soybeans at Jabalpur, M. P. India. Communications in Soil Science and Plant Analysis 2:283292.
176 Gupta, B.R., Pathak, R.K., Bhan, S., and Singh, A. 1972. Effect of NPK on yield, nutrient uptake and quality of toria (Brassica campestris Var. Toria T.9). Indian Journal of Agronomy 17:8891.
177 Stilwell, T.C., Sekhon, G.S., and Arscott, T.G. 1975. Response to potassium fertilization of three Punjab soils. Indian Journal of Agricultural Science 45:149151.
178 Grewal, J.S. and Singh, S.N. 1980. Effect of potassium nutrition on frost damage and yield of potato plants on alluvial soils of the Punjab (India). Plant and Soil 57:105110.
179 Mehta, S.C., Singh, N., Mittal, S.B., and Singh, M. 1991. Response of paddy and wheat to nitrogen and potassium fertilization. Crop Research 4:8489.
180 Subramanian, K.S. 1994. Influence of soil and foliar application of potassium on growth, nutrient utilization, yield and quality of sugarcane (Saccharum officinarum L.). New Botanist 21:1320.
181 Singh, K.N. and Sharma, D.P. 2001. Response of wheat to nitrogen and potassium in saline soils. Experimental Agriculture 37:417427.
182 Kumar, P., Pandey, S.K., Singh, S.V., Rawal, S., and Kumar, D. 2004. Effect of potassium fertilization on processing grade tuber yield and quality parameters in potato (Solanum tuberosum). Indian Journal of Agricultural Science 74:177179.
183 Moinuddin, , Singh, K., Bansal, S.K., and Pasricha, N.S. 2004. Influence of graded levels of potassium fertilizer on growth, yield, and economic parameters of potato. Journal of Plant Nutrition 27:239259.
184 Gunarto, L., Yahya, M., Supadmo, H., and Buntan, A. 1985. Response of corn to NPK fertilization grown in a latosol in South Salawesi, Indionesia. Communications in Soil Science and Plant Analysis 16:11791188.
185 Hanolo, W. and Pulung, M.A. 1994. Effect of P and K fertilizers on growth and yield of pea. Acta Horticulturae 369:335339.
186 Bakhsh, A., Khattak, J.K., and Bhatti, A.U. 1986. Comparative effect of potassium chloride and potassium sulfate on the yield and protein content of wheat in three different rotations. Plant and Soil 96:273277.
187 Khan, Q., Himayatullah, M.N., Khan, N., and Shah, Z. 1994. Effect of various levels of potassium on wheat crop. Sarhad Journal of Agriculture 10:337343.
188 Gormus, O. 2002. Effects of rate and time of potassium application on cotton yield and quality in Turkey. Journal of Agronomy and Crop Science 188:382388.
189 Nguyen, H., Schoenau, J.J., Nguyen, D., Van Rees, K., and Boehm, M. 2002. Effects of long-term nitrogen, phosphorus, and potassium fertilization on cassava yield and plant nutrient composition in North Vietnam. Journal of Plant Nutrition 25:425442.
190 Brennan, R.F. and Bolland, M.D.A. 2007. Influence of potassium and nitrogen fertiliser on yield, oil and protein concentration of canola (Brassica napus L.) grain harvested in south-western Australia. Australian Journal of Experimental Agriculture 47:976983.
191 Hall, A.M. 1975. Effect of phosphorus, potassium, and calcium on peanuts at Mauke (Cook Islands). New Zealand Journal of Experimental Agriculture 3:117120.
192 Rehm, G.W., Sorensen, R.C., and Wiese, R.A. 1981. Application of phosphorus, potassium, and zinc to corn grown for grain or silage: Early growth and yield. Soil Science Society of America Journal 45:523528.
193 Hoeft, R.G., Walsh, L.M., and Liegel, E.A. 1975. Effect of seed-placed fertilizer on the emergence (germination) of soybeans (Glycine max L.) and snapbeans (Phaseolus vulgaris L.). Communications in Soil Science and Plant Analysis 6:655664.
194 Mascarenhas, H.A.A., Hiroce, R., and Braga, N.R. 1976. Cloreto de potassio para a soja. Bragantia 35:CXXVCXXVII.
195 Sangoi, L., Ernani, P.R., Bianchet, P., Vargas, V.P., and Picoli, G.J. 2009. Efeito de doses de cloreto de potássio sobre a germinação e o crescimento inicial do milho, em solos com texturas contrastantes. Revista Brasileira de Milho e Sorgo 8:187197.
196 Curtin, D., Steppuhn, H., Campbell, C.A., and Biederbeck, V.O. 1999. Carbon and nitrogen mineralization in soil treated with chloride and phosphate salts. Canadian Journal of Soil Science 79:427429.
197 Roseberg, R.J., Christensen, N.W., and Jackson, T.L. 1986. Chloride, soil solution osmotic potential, and soil pH effects on nitrification. Soil Science Society of America Journal 50:941945.
198 Smith, D. and Peterson, L.A. 1975. Chlorine concentrations in alfalfa herbage and soil with KCl topdressing of a low fertility silt loam soil. Communications in Soil Science and Plant Analysis 6:521533.
199 Hahn, B.E., Olson, F.R., and Roberts, J.L. 1942. Influence of potassium chloride on nitrification in Bedford silt loam. Soil Science 54:113121.
200 Golden, D.C., Sivasubramaniam, S., Sandanam, S., and Wijedasa, M.A. 1984. Inhibitory effects of commercial potassium chloride on the nitrification rates of added ammonium sulphate in an acid red yellow podzolic soil. Tea Quarterly 53:4346.
201 Younts, S.E. and Musgrave, R.B. 1958. Chemical composition, nutrient absorption, and stalk rot incidence of corn as affected by chloride in potassium fertilizer. Agronomy Journal 50:426429.
202 Timm, C.A., Goos, R.J., Johnson, B.E., Sobolik, F.J., and Stack, R.W. 1986. Effect of potassium fertilizers on malting barley infected with common root rot. Agronomy Journal 78:197200.
203 Johnston, A.E., Goulding, K.W.T., and Mercer, E. 1993. Potassium leaching from a sandy loam soil. Potash Review 12(4):116.
204 Askegaard, M. and Eriksen, J. 2000. Potassium retention and leaching in an organic crop rotation on loamy sand as affected by contrasting potassium budgets. Soil Use and Management 16:200205.
205 Brye, K.R. and Norman, J.M. 2004. Land-use effects on anion-associated cation leaching in response to above-normal precipitation. Acta Hydrochimica et Hydrobiologica 32:235248.
206 Karamanos, R.E., Harapiak, J.T., and Flore, N.A. 2003. Application of seed-row potash to barley (Hordeum vulgare L.) grown on soils with high “available” potassium levels. Canadian Journal of Plant Science 83:291303.
207 Brennan, R.F. and Jayasena, K.W. 2007. Increasing applications of potassium fertiliser to barley crops grown on deficient sandy soils increased grain yields while decreasing some foliar diseases. Australian Journal of Agricultural Research 58:680689.
208 Grant, C.A., Bailey, L.D., and Therrien, M.C. 1996. The effect of N, P and KCl fertilizers on grain yield and Cd concentration of malting barley. Fertilizer Research 45:153161.
209 Zubriski, J.C., Vasey, E.H., and Norum, E.B. 1970. Influence of nitrogen and potassium fertilizers and date of seeding on yield and quality of malting barley. Agronomy Journal 62:216219.
210 Tinline, R.D., Ukrainetz, H., and Spurr, D.T. 1993. Effect of fertilizers and of liming acid soil on common root rot in wheat, and of chloride on the disease in wheat and barley. Canadian Journal of Plant Pathology 15:6573.
211 Walker, W.M. and Raines, G.A. 1988. Effect of corn cultivar, phosphorus and potassium on yield and chemical composition. Journal of Plant Nutrition 11:17151726.
212 Heckman, J.R. 1998. Corn stalk rot suppression and grain yield response to chloride. Journal of Plant Nutrition 21:149155.
213 Ebelhar, S.A., Kamprath, E.J., and Moll, R.H. 1987. Effects of nitrogen and potassium on growth and cation composition of corn genotypes differing in average ear number. Agronomy Journal 79:875881.
214 Fintel, R.G.H. von and Quicke, G.V. 1962. Soil fertilization and the protein, zein, essential amino acid and niacin content of maize grain. South African Journal of Agricultural Science 5:165175.
215 Boswell, F.C. and Parks, W.L. 1957. The effect of soil potassium levels on yield, lodging, and mineral composition of corn. Soil Science Society of America Proceedings 21:301305.
216 Liebhardt, W.C. and Murdock, J.T. 1965. Effect of potassium on morphology and lodging of corn. Agronomy Journal 57:325328.
217 Haq, M.U. and Mallarino, A.P. 2005. Response of soybean grain oil and protein concentrations to foliar and soil fertilization. Agronomy Journal 97:910918.
218 Helz, G.E. and Whiting, A.L. 1928. Effects of fertilizer treatment on the formation of nodules on the soybean. Journal of the American Society of Agronomy 20:975981.
219 Sharma, P., Duveiller, E., and Sharma, R.C. 2006. Effect of mineral nutrients on spot blotch severity in wheat, and associated increases in grain yield. Field Crops Research 95:426430.
220 Norvell, W.A., Wu, J., Hopkins, D.G., and Welch, R.M. 2000. Association of cadmium in durum wheat grain with soil chloride and chelate-extractable soil cadmium. Soil Science Society of America Journal 64:21622168.
221 Wahhab, A. and Ali, R. 1962. Effect of nitrogen, phosphorus and potash on lodging, yield, plant characters and the chemical composition of irrigated wheat. Pakistan Journal of Scientific Research 14:816.
222 Bennett, O.L., Rouse, R.D., Ashley, D.A., and Doss, B.D. 1965. Yield, fiber quality and potassium content of irrigated cotton plants as affected by rates of potassium. Agronomy Journal 57:296299.
223 Bernardi, A.C. de C., Oliveira, J.P. de Jr, Leandro, W.M., Mesquita, T.G. da S., Freitas, P.L. de, and Carvalho, M. da C.S. 2009. Doses e formas de aplicação da adubação potássica na rotação soja, milheto e algodão em sistema plantio direto. Pesquisa Agropecuária Tropical 39:158167.
224 Cassman, K.G., Kerby, T.A., Roberts, B.A., Bryant, D.C., and Higashi, S.L. 1990. Potassium nutrition effects on lint yield and fiber quality of Acala cotton. Crop Science 30:672677.
225 Minton, E.B. and Ebelhar, M.W. 1991. Potassium and aldicarb-disulfoton effects on verticillium wilt, yield, and quality of cotton. Crop Science 31:209212.
226 Pettigrew, W.T., Heitholt, J.J., and Meredith, W.R. Jr 1996. Genotypic interactions with potassium and nitrogen in cotton of varied maturity. Agronomy Journal 88:8993.
227 Pettigrew, W.T., Meredith, W.R. Jr, and Young, L.D. 2005. Potassium fertilization effects on cotton lint yield, yield components, and reniform nematode populations. Agronomy Journal 97:12451251.
228 Peters, J.B., Kelling, K.A., Speth, P.E., and Offer, S.M. 2005. Alfalfa yield and nutrient uptake as affected by pH and applied K. Communications in Soil Science and Plant Analysis 36:583596.
229 Rogers, G., Porter, R., Jolley, L.C., and Leaver, D.D. 1977. Management factors and grass tetany in dairy cattle. Australian Veterinary Journal 53:523528.
230 Ketterings, Q.M., Godwin, G., Cherney, J.H., and Kilcer, T.F. 2005. Potassium management for brown midrib sorghum × sudangrass as replacement for corn silage in the north-eastern USA. Journal of Agronomy and Crop Science 191:4146.
231 Meissner, A.P. and Clarke, A.L. 1977. Response of mown pasture to potassium fertilizer in south-eastern South Australia. Australian Journal of Experimental Agriculture and Animal Husbandry 17:765775.
232 Balasko, J.A. 1977. Effects of N, P, and K fertilization on yield and quality of tall fescue forage in winter. Agronomy Journal 69:425428.
233 Brennan, R.F. and Bolland, M.D.A. 2006. Soil and tissue tests to predict the potassium requirements of canola in south-western Australia. Australian Journal of Experimental Agriculture 46:675679.
234 Li, Y.-M., Chaney, R.L., and Schneiter, A.A. 1994. Effect of soil chloride level on cadmium concentration in sunflower kernels. Plant and Soil 167:275280.
235 Tinker, P.B.H. 1965. The effects of nitrogen, potassium and sodium fertilizers on sugar beet. Journal of Agricultural Science, Cambridge 65:207212.
236 Otto, R., Vitti, G.C., and de Cerqueira Luz, P.H. 2010. Manejo da adubação potássica na cultura da cana-de-açúcar. Revista Brasileira de Ciencia do Solo 34:11371145.
237 Gascho, G.J. and Kidder, G. 1979. Responses to Phosphorus and Potassium and Fertilizer Recommendations for Sugarcane in South Florida. Florida Agricultural Experimental Station Bulletin 809. University of Florida, Gainesville, FL.
238 Maier, N.A., Dahlenburg, A.P., and Frensham, A.B. 1986. Potassium nutrition of irrigated potatoes in South Australia. 3. Effect on specific gravity, size and internal bruising of tubers. Australian Journal of Experimental Agriculture 26:737744.
239 Sparrow, L.A., Salardini, A.A., and Johnstone, J. 1994. Field studies of cadmium in potatoes (Solanum tuberosum L.). III. Response of cv. Russet Burbank to sources of banded potassium. Australian Journal of Agricultural Research 45:243249.
240 McLaughlin, M.J., Maier, N.A., Freeman, K., Tiller, K.G., Williams, C.M.J., and Smart, M.K. 1995. Effect of potassic and phosphatic fertilizer type, fertilizer Cd concentration and zinc rate on cadmium uptake by potatoes. Fertilizer Research 40:6370.
241 Allison, M.F., Fowler, J.H., and Allen, E.J. 2001. Responses of potato (Solanum tuberosum) to potassium fertilizers. Journal of Agricultural Science, Cambridge 136:407426.
242 McDole, R.E. 1978. Potassium fertilizer trials with potatoes on coarse-textured soils in southeastern Idaho. American Potato Journal 55:161170.
243 Herlihy, M. and Carroll, P.J. 1969. Effects of N, P and K and their interactions on yield, tuber blight and quality of potatoes. Journal of the Science of Food and Agriculture 20:513517.
244 Murphy, H.J. and Goven, M.J. 1959. Factors Affecting the Specific Gravity of the White Potato in Maine. Maine Agricultural Experiment Station Bulletin 583. University of Maine, Orono, ME.
245 Hahlin, M. and Johansson, O. 1973. Fosfor- och kaliumgödsling till matpotatis. Lantbruks-högskolans meddelande. Serie A. NR 192. Royal Agricultural College of Sweden, Uppsala, Sweden.
246 Constantin, R.J., Jones, L.G., and Hernandez, T.P. 1977. Effects of potassium and phosphorus fertilization on quality of sweet potatoes. Journal of the American Society of Horticultural Science 102:779781.
247 McLaughlin, M.J., Palmer, L.T., Tiller, K.G., Beech, T.A., and Smart, M.K. 1994. Increased soil salinity causes elevated cadmium concentrations in field-grown potato tubers. Journal of Environmental Quality 23:10131018.
248 Julin, B., Wolk, A., Bergkvist, L., Bottai, M., and Åkesson, A. 2012. Dietary cadmium exposure and risk of postmenopausal breast cancer: A population-based prospective cohort study. Cancer Research 72:14591466.
249 Goff, J.P. and Horst, R.L. 1997. Effects of addition of potassium or sodium, but not calcium, to prepartum rations on milk fever in dairy cows. Journal of Dairy Science 80:176186.
250 Horst, R.L., Goff, J.P., Reinhardt, T.A., and Buxton, D.R. 1997. Strategies for preventing milk fever in dairy cattle. Journal of Dairy Science 80:12691280.
251 Allcroft, R. and Burns, K.N. 1968. Hypomagnesaemia in cattle. New Zealand Veterinary Journal 16:109128.
252 Cherney, J.H., Cherney, D.J.R., and Bruulsema, T.W. 1998. Potassium management. In Cherney, J.H. and Cherney, D.J.R. (eds). Grass for Dairy Cattle. CAB International, Wallingford, England. p. 137160.
253 McCalla, T.M. 1937. Behavior of Legume Bacteria (Rhizobium) in Relation to Exchangeable Calcium and Hydrogen Ion Concentration of the Colloidal Fraction of the Soil. Missouri Agricultural Experiment Station Research Bulletin 256. University of Missouri, Columbia, MO.
254 Albrecht, W.A. and Davis, F.L. 1929. Physiological importance of calcium in legume inoculation. Botanical Gazette 88:310321.
255 Heaney, R.P. and Barger-Lux, M.J. 1994. Low calcium intake: The culprit in many chronic diseases. Journal of Dairy Science 77:11551160.
256 Wu, K., Willett, W.C., Fuchs, C.S., Colditz, G.A., and Giovannucci, E.L. 2002. Calcium intake and risk of colon cancer in women and men. Journal of the National Cancer Institute 94:437446.
257 Newmark, H.L., Heaney, R.P., and Lachance, P.A. 2004. Should calcium and vitamin D be added to the current enrichment program for cereal-grain products? American Journal of Clinical Nutrition 80:264270.
258 Nordin, B.E.C. 1997. Calcium and osteoporosis. Nutrition 13:664686.
259 Centeno, V., de Barboza, G.D., Marchionatti, A., Rodríguez, V., and de Talamoni, N.T. 2009. Molecular mechanisms triggered by low-calcium diets. Nutrition Research Reviews 22:163174.
260 Krauss, A. and Saurat, A. 1989. Potassium sulphate: K fertilizers for arid and semi-arid zones. In Proceedings of the Workshop on the Role of Potassium in Improving Fertilizer Use Efficiency. National Fertilizer Development Corporation, Islamabad, Pakistan. p. 171185.
261 Lucas, R.E., Wheeler, E.J., and Davis, J.F. 1954. Effect of potassium carriers and phosphate:potash ratios on the yield and quality of potatoes grown in organic soils. American Potato Journal 31:349352.
262 Dickins, J.C., Harrap, F.E.G., and Holmes, M.R.J. 1962. Field experiments comparing the effects of muriate and sulphate of potash on potato yield and quality. Journal of Agricultural Science, Cambridge 59:319326.
263 Rowberry, R.G., Sherrell, C.G., and Johnston, G.R. 1963. Influence of rates of fertilizer and sources of potassium on the yield, specific gravity and cooking quality of Katahdin potatoes. American Potato Journal 40:177181.
264 Lujan, L. and Smith, O. 1964. Potato quality XXV. Specific gravity and after-cooking darkening of Katahdin potatoes as influenced by fertilizers. American Potato Journal 41:274278.
265 Højmark, J.V. 1977. Virkningen af stigende mængde kaliumklorid og kaliumsulfat på kartoffeludbytte, kogekvalitet og farve af chips. Tiddskrift for Planteavl 81:6880.
266 Rosolem, C.A., Nakagawa, J., Machado, J.R., and Yamada, T. 1979. Efeitos de modos de aplicação, doses e fontes de potássio na produção da soja. Revista de Agricultura, Piracicaba 54:1319.
267 Abd El-Hadi, A.H., Khadr, M.S., El-Kholy, M.H., Zahran, F.A., and Negm, A.Y. 2002. Comparative effect of potassium sulphate and potassium chloride on crop production and soil chemical properties under Egyptian conditions. Egyptian Journal of Agricultural Research 80:521537.
268 Bansil, P.C. 2004. Agricultural subsidies. A global view. In Dorin, B. and Jullien, T. (eds). Agricultural Incentives in India. Past Trends and Prospective Paths Towards Sustainable Development. Manohar Publishers, New Delhi, India. p. 3965.
269 Environmental Working Group. 2012. Farm Subsidy Database. Available at Web site (verified May 25, 2012).
270 Brown, W.W. 1950–1963. Commercial Fertilizer Year Book. Walter W. Brown, Atlanta, GA.
271 Illinois Department of Agriculture. 1964–2010. Illinois Commercial Fertilizer Tonnage Report. Illinois Department of Agriculture, Springfield, IL. Available since 2004 at Web site (verified August 9, 2012).
272 United States Department of Agriculture. 2012. USDA National Agricultural Statistics Service. Available at Web site (verified May 25, 2012).
273 Tributh, H., Boguslawski, E.v., Lieres, A.v., Steffens, D., and Mengel, K. 1987. Effect of potassium removal by crops on transformation of illitic clay minerals. Soil Science 143:404409.
274 Frydman, S., Ravina, E., and Ehrenreich, T. 1977. Stabilization of heavy clay with potassium chloride. Geotechnical Engineering 8:95108.
275 Abood, T.T., Kasa, A.B., and Chik, Z.B. 2007. Stabilisation of silty clay soil using chloride compounds. Journal of Engineering Science and Technology 2:102110. Available at Web site (verified August 9, 2012).
276 Chaitanya G, K.N.K., Prasada Raju, G.V.R., and Ramu, K. 2011. Evaluation studies of expansive soil treated with electrolytes. International Journal of Engineering Science and Technology 3:82988306. Available at Web site (verified August 9, 2012).
277 Venkara Muthyalu, P., Ramu, K., and Prasada Raju, G.V.R. 2012. Study on performance of chemically stabilized expansive soil. International Journal of Advances in Engineering and Technology 2:139148. Available at Web site (verified August 9, 2012).
278 Deist, J. and Talibudeen, O. 1967. Ion exchange in soils from the ion pairs K-Ca, K-Rb, and K-Na. Journal of Soil Science 18:125137.
279 Palaniappan, S., Peck, T.R., and Beavers, A.H. 1973. Effect of application of high rates of potassium on cation exchange capacity and potassium status of two Illinois soils. Communications in Soil Science and Plant Analysis 4:3140.
280 Cassman, K.G., Roberts, B.A., Kerby, T.A., Bryant, D.C., and Higashi, S.L. 1989. Soil potassium balance and cumulative cotton response to annual potassium additions on a vermiculitic soil. Soil Science Society of America Journal 53:805812.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Renewable Agriculture and Food Systems
  • ISSN: 1742-1705
  • EISSN: 1742-1713
  • URL: /core/journals/renewable-agriculture-and-food-systems
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Type Description Title
Supplementary materials

Khan Supplementary Material

 Word (885 KB)
885 KB


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed