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DEVELOPMENT OF CONSERVATION AGRICULTURE (CA) SYSTEMS IN MALAWI: LESSONS LEARNED FROM 2005 TO 2014

Published online by Cambridge University Press:  20 November 2015

CHRISTIAN THIERFELDER ,
W. TRENT BUNDERSON ,
ZWIDE D. JERE ,
MUNYARADZI MUTENJE  and
AMOS NGWIRA
CHRISTIAN THIERFELDER*
Affiliation:
CIMMYT, P.O. Box MP 163. Mount Pleasant, Harare, Zimbabwe
W. TRENT BUNDERSON
Affiliation:
Total LandCare, PO Box 2440, Lilongwe, Malawi
ZWIDE D. JERE
Affiliation:
Total LandCare, PO Box 2440, Lilongwe, Malawi
MUNYARADZI MUTENJE
Affiliation:
CIMMYT, P.O. Box MP 163. Mount Pleasant, Harare, Zimbabwe
AMOS NGWIRA
Affiliation:
Chitedze Research Station, P. O. Box 158, Lilongwe, Malawi
*
‡Corresponding author. Email: c.thierfelder@cgiar.org
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Summary

Conservation agriculture (CA) was introduced to farmers in Malawi to address soil degradation, declining crop productivity and the need to adapt to climate variability and change. This research from 2005 to 2014 aimed at analysing the effects of CA on longer-term productivity and profitability compared with conventional systems as practiced in two communities of Central Malawi. CA treatments outyielded conventional ridge tilled control plots in Mwansambo and Zidyana on average by between 22 and 31%, respectively. An economic analysis from 2011 to 2014 found that, on average, income was 50 and 83% greater in CA systems than in conventional systems. The crops were produced with 28 -39 less labour days ha−1 compared with the conventional practice, leading to greater net benefits. Despite the higher returns with CA, there are still challenges with residue retention, weed control, adequate rotations, management of pests and diseases as well as other socio-economic constraints. At the same time, there are opportunities to address these challenges through site-specific and adaptive research using innovation systems approaches.

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Type
Research Article
Information
Experimental Agriculture , Volume 52 , Issue 4 , October 2016 , pp. 579 - 604
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Copyright © Cambridge University Press 2015 

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References

REFERENCES

Aagaard, P. (2011). The Practice of Conventional and Conservation Agriculture in East and Southern Africa. Lusaka, Zambia: Conserv. Farm. Unit Zambia.Google Scholar
Andersson, J. A. and D’Souza, S. (2014). From adoption claims to understanding farmers and contexts: a literature review of conservation agriculture (CA) adoption among smallholder farmers in southern Africa. Agriculture, Ecosystems & Environment 187:116–132.CrossRefGoogle Scholar
Arslan, A., McCarthy, N., Lipper, L., Asfaw, S. and Cattaneo, A. (2014). Adoption and intensity of adoption of conservation farming practices in Zambia. Agriculture, Ecosystems & Environment 187:72–86.Google Scholar
Baudron, F., Andersson, J. A., Corbeels, M. and Giller, K. E. (2012a). Failing to yield? Ploughs, conservation agriculture and the problem of agricultural intensification: an example from the Zambezi Valley. Zimbabwe Journal of Development Studies 48 (3):383–412.Google Scholar
Baudron, F., Tittonell, P., Corbeels, M., Letourmy, P. and Giller, K. E. (2012b). Comparative performance of conservation agriculture and current smallholder farming practices in semi-arid Zimbabwe. Field Crops Research 132:117–128.Google Scholar
Bolliger, A. (2007). Is Zero-till An Appropriate Agricultural Alternative for Disadvantaged Smallholders of South Africa? A Study of Surrogate Systems and Strategies, Smallholder Sensitivities and Soil Glycoproteins. PhD thesis, University of Copenhagen.Google Scholar
Bolliger, A., Magid, J., Amado, T. J. C., Scora Neto, F., Dos Santos Ribeiro, M. D. F., Calegari, A., Ralisch, R. and De Neergaard, A. (2006). Taking stock of the Brazilian ‘zero-till revolution’: a review of landmark research an farmers’ practice. Advances in Agronomy 91:47–110.Google Scholar
Bunderson, W. T., Jere, Z. D., Chisui, J. L., Museka, R., Mbale, B. and N’goma, S. (2011). Guidelines for Conservation Agriculture in East and Southern Africa. TLC, Lilongwe, Malawi: Total LandCare Booklet Publication No. 4, December 2011.Google Scholar
Bunderson, W. T., Jere, Z. D., Thierfelder, C., Gama, M., Mwale, B. M., Ng’oma, S. W. D., Museka, R., Paul, J. M., Mbale, B., Mkandawire, O. and Tembo, P. (In press). Implementing the principles of conservation agriculture in Malawi: crop yields and factors affecting adoption. In Conservation Agriculture for Africa: Building Resilient Farming Systems in a Changing Climate (Eds Mkwomwa, S. and Kassam, A.). Wallingford, UK: CABI Publishing.Google Scholar
Cairns, J. E., Hellin, J., Sonder, K., Araus, J. L., MacRobert, J. F., Thierfelder, C. and Prasanna, B. (2013). Adapting maize production to climate change in sub-Saharan Africa. Food Security 5 (3):345–360.Google Scholar
CIMMYT. (1988). From Agronomic Data to Farmer Recommendations: An Economics Training Manual (Completely Revised Edition). Mexico: CIMMYT.Google Scholar
Derpsch, R. (2007). Making conservation tillage conventional, buliding a future on 25 years of research: research and extension perpective, In Proceeding of 25th Southern Conservation Tillage Conference, 11:25–29.Google Scholar
Derpsch, R., Roth, C., Sidiras, N. and Köpke, U. (1991). Controle de Erosao no Parana, Brazil: Sistemas de Cobertura do Solo, Plantio Direto e Preparo Conservacionista do Solo. Eschborn, Germany: Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH.Google Scholar
Derpsch, R., Sidiras, N. and Roth, C. F. (1986). Results of studies made from 1977–1984 to control erosion by cover crops and no-tillage techniques in Parana, Brazil. Soil and Tillage Research 8:253–263.CrossRefGoogle Scholar
Dowswell, C. R., Paliwal, R. L. and Cantrell, R. P. (1996). Maize in the Third World. Colorado, USA: Westview Press.Google Scholar
Ekboir, J. (2002). CIMMYT 2000–2001 World Wheat Overview and Outlook: Developing no-till Packages for Small-Scale Farmers. Mexico, DF: CIMMYT.Google Scholar
Ekboir, J., Boa, K. and Dankyii, A. A. (2002). The impact of no-till in Ghana. In Conservation Agriculture: A Worldwide Challenge, 757–764 (Eds Garcia-Torres, L., Benites, J., Martinez-Vilela, A. and Holgado-Cabrera, A.). Cordoba, Spain: ECAF/FAO.Google Scholar
Ellis, F., Kutengule, M. and Nyasulu, A. (2003). Livelihoods and rural poverty reduction in Malawi. World Development 31:1495–1510.Google Scholar
Erenstein, O. (2002). Crop residue retention in tropical and semi-tropisal countries: an evaluation of residue availability and other technological implications. Soil and Tillage Research 67:115–133.Google Scholar
Erenstein, O. (2009). Specification effects in zero tillage survey data in South Asia's rice-wheat systems. Field Crops Research 111 (1–2):166–172.Google Scholar
Erenstein, O. and Laxmi, V. (2008). Zero tillage impacts in India's rice-wheat systems: a review. Soil and Tillage Research 100 (1–2):1–14.Google Scholar
Erenstein, O., Sayre, K., Wall, P., Hellin, J. and Dixon, J. (2012). Conservation agriculture in maize- and wheat-based systems in the (Sub)tropics: lessons from adaptation initiatives in South Asia, Mexico, and Southern Africa. Journal of Sustainable Agriculture 36 (2):180–206.Google Scholar
FAO. (2002). Conseration agriculture: case studies in Latin America and Africa. In FAO Soils Bulle-tin, vol. 78. Rome: FAO.Google Scholar
Garrity, D., Akinnifesi, F., Ajayi, O., Sileshi, G. W., Mowo, J. G., Kalinganire, A., Larwanou, M. and Bayala, J. (2010). Evergreen agriculture: a robust approach to sustainable food security in Africa. Food Security 2 (3):197–214.CrossRefGoogle Scholar
Giller, K. E., Corbeels, M., Nyamangara, J., Triomphe, B., Affholder, F., Scopel, E. and Tittonell, P. (2011). A research agenda to explore the role of conservation agriculture in African smallholder farming systems. Field Crops Research 124:468–472.Google Scholar
Giller, K. E., Witter, E., Corbeels, M. and Tittonell, P. (2009). Conservation agriculture and smallholder farming in Africa: the heretic's view. Field Crops Research 114:23–34.Google Scholar
Govaerts, B., Mezzalama, M., Sayre, K. D., Crossa, J., Nicol, J. M. and Deckers, J. (2006). Long-term consequences of tillage, residue management, and crop rotation on maize/wheat root rot and nematode populations in subtropical highlands. Applied Soil Ecology 32:305–315.Google Scholar
Govaerts, B., Sayre, K., Lichter, K., Dendooven, L. and Deckers, J. (2007). Influence of permanent raised bed planting and residue management on physical and chemical soil quality in rain fed maize/wheat systems. Plant and Soil 291 (1):39–54.CrossRefGoogle Scholar
Govaerts, B., Sayre, K. D. and Deckers, J. (2005). Stable high yields with zero tillage and permanent bed planting? Field Crops Research 94 (1):33–42.Google Scholar
Govaerts, B., Verhulst, N., Castellanos-Navarrete, A., Sayre, K. D., Dixon, J. and Dendooven, L. (2009). Conservation agriculture and soil carbon sequestration: between myth and farmer reality. Critical Reviews in Plant Sciences 28:97–122.Google Scholar
Grabowski, P. P. and Kerr, J. M. (2014). Resource constraints and partial adoption of conservation agriculture by hand-hoe farmers in Mozambique. International Journal of Agricultural Sustainability 12 (1):37–53.Google Scholar
Grabowski, P. P., Kerr, J. M., Haggblade, S. and Kabwe, S. (2014). Determinants of Adoption of Minimum Tillage by Cotton Farmers in Eastern Zambia. East Lansing, USA: Michigan State University, Department of Agricultural, Food, and Resource Economics.Google Scholar
Haggblade, S. and Tembo, G. (2003). Conservation Farming in Zambia: EPTD Discussion Paper No. 108. Washington DC: IFPRI.Google Scholar
Harrington, L. and Erenstein, O. (2005). Conservation agriculture and resource conserving technologies: a global perspective. In Conservation Agriculture Status and Prospects, 1–12 (Eds Abrol, I. P., Gupta, R. K. and Malik, R. K.). New Delhi: Centre for Advancement of Sustainable Agriculture.Google Scholar
Hobbs, P. R. (2007). Conservation agriculture: what is it and why is it important for future sustainable food production? Journal of Agricultural Science 145:127–137.Google Scholar
IPCC5. (2014). Climate change 2014: impact adaptation and vulnerability, chapter 22, Africa. Working Group II Fifth Assessment Report (AR5). Geneva, Switzerland: Intergovernmental Panel on Climate Change.Google Scholar
Ito, M., Matsumoto, T. and Quinones, M. A. (2007). Conservation tillage practices in sub-Saharan Africa: the experience of Sassaka Global 2000. Crop Protection 26:417–423.Google Scholar
Jat, M., Gathala, M., Ladha, J., Saharawat, Y., Jat, A., Kumar, V., Sharma, S., Kumar, V. and Gupta, R. (2009). Evaluation of precision land leveling and double zero-till systems in the rice–wheat rotation: water use, productivity, profitability and soil physical properties. Soil and Tillage Research 105 (1):112–121.Google Scholar
Johansen, C., Haque, M., Bell, R., Thierfelder, C. and Esdaile, R. (2012). Conservation agriculture for small holder rainfed farming: opportunities and constraints of new mechanized seeding systems. Field Crops Research 132:18–32.Google Scholar
Kassam, A., Friedrich, T., Shaxson, F. and Pretty, J. (2009). The spread of conservation agriculture: justification, sustainability and uptake. International Journal of Agricultural Sustainability 7 (4):292–320.Google Scholar
Kumwenda, J. D. T., Waddington, S. R., Snapp, S. S., Jones, R. B. and Blackie, M. J. (1998). Soil Fertility Management in Southern Africa. In Africa's Emerging Maize Revolution, 305 (Eds Byerlee, D. and Eicher, C. K.). Colorado, USA: Lynne Rienner Publishers.Google Scholar
Lal, R. (1974a). No-tillage effects on soil properties and maize (Zea mays L.) production in Western Nigeria. Plant and Soil 40 (2):321–331.Google Scholar
Lal, R. (1974b). Soil temperature, soil moisture and maize yield from mulched and unmulched tropical soils. Plant and Soil 40 (1):129–143.CrossRefGoogle Scholar
Mazvimavi, K. (2011). Socio-economic analysis of conservation agriculture in Southern Africa Johannesburg, South Africa: food and agricultural organization of the United Nations (FAO). Regional Emergency Office for Southern Africa (REOSA). Network paper 02, January 2011.Google Scholar
Mazvimavi, K. and Twomlow, S. (2009). Socioeconomic and institutional factors influencing adoption of conservation agriculture by vulnerable households in Zimbabwe. Agricultural Systems 101:20–29.Google Scholar
Mazvimavi, K., Twomlow, S. J., Bell, J. P. and Howe, L. (2008). An assessment of the sustainable uptake of conservation farming in Zimbabwe. Global Theme on Agroecosystems Report no. 39. International Crops Research Institute for the Semi-Arid Tropics, Bulawayo, Zimbabwe.Google Scholar
McConnell, D. J. and Dillon, J. L. (1997). Farm Management for Asia: A Systems Approach. Farm Management Series 13. Rome, Italy: Food & Agriculture Organization of the United Nations (FAO).Google Scholar
Mhlanga, B., Cheesman, S., Maasdorp, B., Muoni, T., Mabasa, S., Mangosho, E. and Thierfelder, C. (2015). Weed community responses to rotations with cover crops in maize-based conservation agriculture systems of Zimbabwe. Crop Protection 69:1–8.Google Scholar
Mueller, J. P., Pezo, D. A., Benites, J. and Schlaepfer, N. P. (2001). Conflicts between conservation agriculture and livestock over utilization of crop residues. In Conservation Agriculture: A Worldwide Challenge, 211–225 (Eds Garcia-Torres, L., Benites, J. and Mart¡nez-Vilela, A.). Cordoba, Spain: ECAF/FAO.Google Scholar
Muoni, T., Rusinamhodzi, L., Rugare, J. T., Mabasa, S., Mangosho, E., Mupangwa, W. and Thierfelder, C. (2014). Effect of herbicide application on weed flora under conservation agriculture in Zimbabwe. Crop Protection 66:1–7.Google Scholar
Muoni, T., Rusinamhodzi, L. and Thierfelder, C. (2013). Weed control in conservation agriculture systems of Zimbabwe: identifying economical best strategies. Crop Protection 53:23–28.Google Scholar
Mupangwa, W. and Thierfelder, C. (2014). Intensification of conservation agriculture systems for increased livestock feed and maize production in Zimbabwe. International Journal of Agricultural Sustainability 12 (4):425–439.Google Scholar
Mupangwa, W., Twomlow, S. and Walker, S. (2012). Reduced tillage, mulching and rotational effects on maize (Zea mays L.), cowpea (Vigna unguiculata (Walp) L.) and sorghum (Sorghum bicolor L. (Moench)) yields under semi-arid conditions. Field Crops Research 132 (0):139–148.Google Scholar
Mwale, C. (2009). Effect of Tillage Practices on Weed Populations and Seed Banks in Maize Based Production Systems in Malawi, vol. Msc, 1–45 31. July 2009: Master thesis, ISARA-Lyon, University of Lyon.Google Scholar
Myaka, F. M., Sakala, W. D., Adu-Gyamfi, J. J., Kamalongo, D., Ngwira, A., Odgaard, R., Nielsen, N. E. and Høgh-Jensen, H. (2006). Yields and accumulations of N and P in farmer-managed intercrops of maize-pigeonpea in semi-arid Africa. Plant and Soil 285 (1–2):207–220.CrossRefGoogle Scholar
Ngwira, A. R., Aune, J. B. and Mkwinda, S. (2012). On-farm evaluation of yield and economic benefit of short term maize legume intercropping systems under conservation agriculture in Malawi. Field Crops Research 132:149–157.CrossRefGoogle Scholar
Ngwira, A. R., Thierfelder, C. and Lambert, D. M. (2013). Conservation agriculture systems for Malawian smallholder farmers: long-term effects on crop productivity, profitability and soil quality. Renewable Agriculture and Food Systems 28 (04):350–363.CrossRefGoogle Scholar
Nyamangara, J., Marondedze, A., Masvaya, E., Mawodza, T., Nyawasha, R., Nyengerai, K., Tirivavi, R., Nyamugafata, P. and Wuta, M. (2014a). Influence of basin-based conservation agriculture on selected soil quality parameters under smallholder farming in Zimbabwe. Soil Use and Management 30 (4):550–559.Google Scholar
Nyamangara, J., Mashingaidze, N., Masvaya, E. N., Nyengerai, K., Kunzekweguta, M., Tirivavi, R. and Mazvimavi, K. (2014b). Weed growth and labor demand under hand-hoe based reduced tillage in smallholder farmers’ fields in Zimbabwe. Agriculture, Ecosystems & Environment 187:146–154.Google Scholar
Nyamangara, J., Masvaya, E. N., Tirivavi, R. and Nyengerai, K. (2013). Effect of hand-hoe based conservation agriculture on soil fertility and maize yield in selected smallholder areas in Zimbabwe. Soil and Tillage Research 126:19–25.Google Scholar
Nyamangara, J., Nyengerai, K., Masvaya, E., Tirivavi, R., Mashingaidze, N., Mupangwa, W., Dimes, J., Hove, L. and Twomlow, S. (2014c). Effect of conservation agriculture on maize yield in the semi-arid areas of Zimbabwe. Experimental Agriculture 50 (02):159–177.Google Scholar
Owenya, M. Z., Mariki, W. L., Kienzle, J., Friedrich, T. and Kassam, A. (2011). Conservation agriculture (CA) in Tanzania: the case of the Mwangaza B CA farmer field school (FFS), Rhotia Village, Karatu District, Arusha. International Journal of Agricultural Sustainability 9 (1):145–152.Google Scholar
Patzek, T. W. (2008). Thermodynamics of Agricultural Sustainability: the case of US Maize Agriculture. Critical Reviews in Plant Sciences 27 (4):272–293.Google Scholar
Ried, K. (2006). Interpreting and understanding meta-analysis graphs: a practical guide. Australian Family Physician 35 (8):635–638.Google Scholar
Rusinamhodzi, L., Corbeels, M., van Wijk, M., Rufino, M., Nyamangara, J. and Giller, K. (2011). A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions. Agronomy for Sustainable Development 31 (4):657–673.Google Scholar
Rycroft, R. W. and Kash, D. E. (1994). Complex technology and community: implications for policy and social sciences. Research Policy 23 (6):613–626.Google Scholar
Sakala, W. (1998). Nitrogen Dynamics in Maize (Zea mays) and Pigeon Pea (Cajanus cajan) Intercropping in Malawi. PhD thesis Department of Biological Sciences, Wye College, University of London, 217.Google Scholar
Sakala, W. D. (1994). Crop management interventions in traditional maize pigeonpea intercropping systems in Malawi. In Bunda College of Agriculture, Vol. MScLilongwe: University of Malawi.Google Scholar
Sanginga, N. and Woomer, P. L. (2009). Integrated Soil Fertility Management in Africa: Principles, Practices and Developmental Process. Cali, Colombia: CIAT.Google Scholar
Sileshi, G., Akinnisfesi, F. K., Ajayi, O. C. and Place, F. (2008). Meta-analysis of maize yield response to woody and herbaceous legumes in sub-Saharan Africa. Plant and Soil 307 (1–2):1–19.Google Scholar
Sims, B. G., Thierfelder, C., Kienzle, J., Friedrich, T. and Kassam, A. (2012). Development of the conservation agriculture equipment industry in sub-Saharan Africa. Applied Engineering in Agriculture 28 (6):813–823.Google Scholar
Smale, M., Kaunda, Z. H. W., Makina, H. L., Mkandawire, M. M. M. K., Msowoya, M. N. S., Mwale, D. J. E. K. and Heisey, P. W. (1991). Chimanga Cha Makolo, Hybrids and Composites: an Analysis of Farmer Adoption of Maize Technology in Malawi. Mexico City, Mexico: CIMMYT: International Maize and Wheat Improvement Center CIMMYT Economics Working Paper 91/04.Google Scholar
Sorrenson, W. J., Duarte, C. and Lopez Portillo, J. (1998). Economics of no-tillage compared to traditional cultivation on small farms in Paraguay, Asunci¢n. MAG/GTZ Soil Conservation Project.Google Scholar
Stagnari, F., Ramazzotti, S. and Pisante, M. (2010). Conservation agriculture: a different approach for crop production through sustainable soil and water management: a review In Organic Farming, Pest Control and Remediation of Soil Pollutants, vol. 1, 55–83 (Ed Lichtfouse, E.). Netherlands: Springer.Google Scholar
Statistix. (2008). Statistix 9: Analytical Software. Tallahassee, USA: www.statistix.com.Google Scholar
Thierfelder, C., Chisui, J. L., Gama, M., Cheesman, S., Jere, Z. D., Bunderson, W. T., Eash, N. S., Ngwira, A. and Rusinamhodzi, L. (2013). Maize-based conservation agriculture systems in Malawi: Long-term trends in productivity. Field Crop Research 142:47–57.Google Scholar
Thierfelder, C., Matemba-Mutasa, R. and Rusinamhodzi, L. (2015a). Yield response of maize (Zea mays L.) to conservation agriculture cropping system in Southern Africa. Soil and Tillage Research 146:230–242.Google Scholar
Thierfelder, C., Mutenje, M., Mujeyi, A. and Mupangwa, W. (2014a). Where is the limit? Lessons learned from long-term conservation agriculture research in Zimuto Communal Area, Zimbabwe. Food Security (7):15–31.Google Scholar
Thierfelder, C., Rusinamhodzi, L., Ngwira, A. R., Mupangwa, W., Nyagumbo, I., Kassie, G. T. and Cairns, J. E. (2015b). Conservation agriculture in Southern Africa: Advances in knowledge. Renewable Agriculture and Food Systems 30 (4):328–348.Google Scholar
Thierfelder, C. and Wall, P. C. (2009). Effects of conservation agriculture techniques on infiltration and soil water content in Zambia and Zimbabwe. Soil and Tillage Research 105 (2):217–227.Google Scholar
Thierfelder, C. and Wall, P. C. (2010a). Investigating Conservation Agriculture (CA) Systems in Zambia and Zimbabwe to Mitigate Future Effects of Climate Change. Journal of Crop Improvement 24 (2):113–121.Google Scholar
Thierfelder, C. and Wall, P. C. (2010b). Rotations in conservation agriculture systems of Zambia: Effects on soil quality and water relations. Experimental Agriculture 46 (03):309–325.Google Scholar
Thierfelder, C. and Wall, P. C. (2011). Reducing the risk of crop failure for smallholder farmers in Africa through the adoption of conservation agriculture. In Innovations as Key to the Green Revolution in Africa, 1269–1277 (Eds Bationo, A., Waswa, B., Okeyo, J. M. M., Maina, F. and Kihara, J. M.). Netherlands: Springer.Google Scholar
Thierfelder, C. and Wall, P. C. (2012). Effects of conservation agriculture on soil quality and productivity in contrasting agro-ecological environments of Zimbabwe. Soil Use and Management 28 (2):209–220.Google Scholar
Umar, B. B. (2014). A critical review and re-assessment of theories of smallholder decision-making: a case of conservation agriculture households, Zambia. Renewable Agriculture and Food Systems 29 (03):277–290.Google Scholar
Umar, B. B., Aune, J. B., Johnsen, F. H. and Lungu, I. O. (2012). Are smallholder zambian farmers economists? A dual-analysis of farmers’ expenditure in conservation and conventional agriculture systems. Journal of Sustainable Agriculture 36 (8):908–929.Google Scholar
Valbuena, D., Erenstein, O., Homann-Kee Tui, S., Abdoulaye, T., Claessens, L., Duncan, A. J., Gérard, B., Rufino, M. C., Teufel, N., van Rooyen, A. and van Wijk, M. T. (2012). Conservation Agriculture in mixed crop–livestock systems: scoping crop residue trade-offs in Sub-Saharan Africa and South Asia. Field Crops Research 132:175–184.Google Scholar
Verhulst, N., Govaerts, B., Verachtert, E., Castellanos-Navarrete, A., Mezzalama, M., Wall, P. C., Chocobar, A., Deckers, J. and Sayre, K. D. (2010). Conservation agriculture, improving soil quality for sustainable production systems. In Advances in Soil Science: Food Security and Soil Quality, 137–208 (Eds Lal, R. and Stewart, B. A.). Boca Raton, FL, USA: CRC Press.Google Scholar
Vogel, H. (1994). Weeds in single-crop conservation farming in Zimbabwe. Soil and Tillage Research 31:169–185.Google Scholar
Wall, P. C. (2007). Tailoring conservation agriculture to the needs of small farmers in developing countries: an analysis of issues. Journal of Crop Improvement 19 (1/2):137–155.Google Scholar
Wall, P. C. and Thierfelder, C. (2009). Some experiences with conservation agriculture in southern Africa. In Increasing the Productivity and Sustainability of Rainfed Cropping Systems of Poor Smallholder Farrmers. Proceedings of the CGIAR Challenge Program on Water and Food International Workshop on Rainfed Systems, Tamale, Ghana 22–25 September 2008, 25–36 (Eds E. Humphreys and R. S. Bayot). Colombo, Sri Lanka: CGIAR Challenge Program on Water and Food.Google Scholar
Wall, P. C., Thierfelder, C., Ngwira, A., Govaerts, B., Nyagumbo, I. and Baudron, F. (2013). Conservation agriculture in Eastern and Southern Africa. In Conservation Agriculture: Global Prospects and Challenges (Eds Jat, R. A., Sahrawat, K. L. and Kassam, A. H.). Wallingford Oxfordshire OX10 8DE, UK: CABI.Google Scholar
Wilcox, R. R. (2006). Kolmogorov-smirnov test for two samples. In Encyclopedia of Measurement and Statistics, 1416 (Ed Salkind, N. J.). UK: SAGE Publications Ltd.Google Scholar
WRB. (1998). World Reference Base on Soils. Rome, Italy: FAO-ISRIC.Google Scholar
ZCATF. (2009). Farming for the Future: A Guide to Conservation Agriculture in Zimbabwe. Harare, Zimbabwe: Zimbabwe Conservation Agriculture Task Force.Google Scholar
Zhang, F. and Li, L. (2003). Using competitive and facilitative interactions in intercropping systems enhances crop productivity and nutrient-use efficiency. Plant and Soil 248:305–312.Google Scholar