4 results
Movement and Germination of Weed Seeds in Ridge-Till Crop Production Systems
- Frank Forcella, Michael J. Lindstrom
-
- Journal:
- Weed Science / Volume 36 / Issue 1 / January 1988
- Published online by Cambridge University Press:
- 12 June 2017, pp. 56-59
-
- Article
- Export citation
-
The dynamics of buried weed seeds in ridge-tilled corn (Zea mays L.) and soybeans [Glycine max (L.) Merr.] were studied in Minnesota. Soils subjected to continuous corn production harbored at least twice as many buried weed seeds as soils under corn/soybean rotations. Truncation of ridges at the time of crop sowing removed 31 to 37% of the buried weed seeds from ridges of continuous corn, and 80 to 100% of those from ridges of the corn/soybean rotations. From 14 to 36% of weed seeds originally in ridges were lost through germination either on the ridge or in the furrow. Ridging soil at layby stimulated germination of numerous weed seeds. The resulting population of small weeds eventually produced up to 1000 seeds/m2 in continuous corn but only about 100 seeds/m2 in corn/soybean rotations, thoroughly replenishing the soil seed reserve in both cropping systems. After 7 to 8 yr of good to excellent weed control with herbicides, crop yield losses in the absence of herbicides were 10 to 27% in continuous corn, and 0% for corn and 6 to 10% for soybeans in corn/soybean rotations.
Weed Seed Populations in Ridge and Conventional Tillage
- Frank Forcella, Michael J. Lindstrom
-
- Journal:
- Weed Science / Volume 36 / Issue 4 / July 1988
- Published online by Cambridge University Press:
- 12 June 2017, pp. 500-503
-
- Article
- Export citation
-
Weed seed and seedling populations, and weed competition were compared in plots of continuous corn and corn/soybean rotation under ridge and conventional tillage. After 7 to 8 yr of standard chemical and mechanical weed control, from 1500 to 3000 weed seeds/m2 (to a 10-cm depth) were found in continuous corn with ridge tillage whereas about two-thirds fewer seeds were found in conventionally tilled corn. Soil from a corn/soybean rotation had from 200 to 700 seeds/m2 in both tillage systems. Annual loss of weed seeds from the soil through germination was from 3 to 12% in ridge tillage and 11 to 43% in conventional tillage. Additions to the seed pool were supplied by small weeds whose germination was stimulated by “layby” cultivation, with up to 10 times more emergence and 140 times more seed production in ridge than in conventional tillage. Withholding herbicides for 1 yr reduced yields of continuous corn by 10 to 27% in ridge tillage, only 2 to 4% in conventional tillage, and negligibly in corn/soybean rotations regardless of tillage. Reducing seed production of small layby weeds in ridge tillage may aid in solving the weed problem in this conservation tillage system.
Covariance of cropping systems and foxtail density as predictors of weed interference
- Milton E. McGiffen, Jr., Frank Forcella, Michael J. Lindstrom, Donald C. Reicosky
-
- Journal:
- Weed Science / Volume 45 / Issue 3 / June 1997
- Published online by Cambridge University Press:
- 12 June 2017, pp. 388-396
-
- Article
- Export citation
-
Regression models of the effect of weed density on crop yield can form the basis of weed management programs by helping growers decide whether weed control is economically justified. However, few studies have examined whether one regression model can be used across a wide range of tillage systems and crop rotations. We used a nonlinear analysis of covariance to examine experiments conducted in 1990 and 1991 on the interaction of weed interference with conventional, fall chisel, and no-till systems, and rotations of corn, soybean, and wheat on a clay loam soil. Corn and soybean suffered heavy losses due to interference by green foxtail (a mixed population of robust purple and robust white varieties). Both tillage system and crop rotation altered the relationship between weed density and yield for corn in 1990 and 1991, but tillage was not a factor for soybean in 1991. Companion experiments on a sandy loam soil found no relationship between weed density and dryland corn yield in the drought year 1990, but weed density greatly decreased yield in irrigated corn. In 1991, the same model fit both dryland and irrigated corn grown in sandy loam soil. Foxtail density did not affect average weight per foxtail plant in any of our experiments, which indicates a lack of intraspecific competition. Competitiveness of corn better explained variation in dry weight per foxtail than did weather. Economic thresholds for foxtail interference are not constant but vary with weather, cropping system, and soil type.
Use of vitamin D supplements during infancy in an international feeding trial
- Eveliina Lehtonen, Anne Ormisson, Anita Nucci, David Cuthbertson, Susa Sorkio, Mila Hyytinen, Kirsi Alahuhta, Carol Berseth, Marja Salonen, Shayne Taback, Margaret Franciscus, Teba González-Frutos, Tuuli E Korhonen, Margaret L Lawson, Dorothy J Becker, Jeffrey P Krischer, Mikael Knip, Suvi M Virtanen, , Thomas Mandrup-Poulsen, Elias Arjas, Åke Lernmark, Barbara Schmidt, Jeffrey P. Krischer, Hans K. Åkerblom, Mila Hyytinen, Mikael Knip, Katriina Koski, Matti Koski, Eeva Pajakkala, Marja Salonen, David Cuthbertson, Jeffrey P. Krischer, Linda Shanker, Brenda Bradley, Hans-Michael Dosch, John Dupré, William Fraser, Margaret Lawson, Jeffrey L. Mahon, Mathew Sermer, Shayne P. Taback, Dorothy Becker, Margaret Franciscus, Anita Nucci, Jerry Palmer, Minna Pekkala, Suvi M. Virtanen, Jacki Catteau, Neville Howard, Patricia Crock, Maria Craig, Cheril L. Clarson, Lynda Bere, David Thompson, Daniel Metzger, Colleen Marshall, Jennifer Kwan, David K. Stephure, Daniele Pacaud, Wendy Schwarz, Rose Girgis, Marilyn Thompson, Shayne P. Taback, Daniel Catte, Margaret L. Lawson, Brenda Bradley, Denis Daneman, Mathew Sermer, Mary-Jean Martin, Valérie Morin, Lyne Frenette, Suzanne Ferland, Susan Sanderson, Kathy Heath, Céline Huot, Monique Gonthier, Maryse Thibeault, Laurent Legault, Diane Laforte, Elizabeth A. Cummings, Karen Scott, Tracey Bridger, Cheryl Crummell, Robyn Houlden, Adriana Breen, George Carson, Sheila Kelly, Koravangattu Sankaran, Marie Penner, Richard A. White, Nancy King, James Popkin, Laurie Robson, Eva Al Taji, Irena Aldhoon, Pavla Mendlova, Jan Vavrinec, Jan Vosahlo, Ludmila Brazdova, Jitrenka Venhacova, Petra Venhacova, Adam Cipra, Zdenka Tomsikova, Petra Krckova, Pavla Gogelova, Ülle Einberg, Mall-Anne Riikjärv, Anne Ormisson, Vallo Tillmann, Päivi Kleemola, Anna Parkkola, Heli Suomalainen, Anna-Liisa Järvenpää, Anu-Maaria Hämälainen, Hannu Haavisto, Sirpa Tenhola, Pentti Lautala, Pia Salonen, Susanna Aspholm, Heli Siljander, Carita Holm, Samuli Ylitalo, Raisa Lounamaa, Anja Nuuja, Timo Talvitie, Kaija Lindström, Hanna Huopio, Jouni Pesola, Riitta Veijola, Päivi Tapanainen, Abram Alar, Paavo Korpela, Marja-Liisa Käär, Taina Mustila, Ritva Virransalo, Päivi Nykänen, Bärbel Aschemeier, Thomas Danne, Olga Kordonouri, Dóra Krikovszky, László Madácsy, Yeganeh Manon Khazrai, Ernesto Maddaloni, Paolo Pozzilli, Carla Mannu, Marco Songini, Carine de Beaufort, Ulrike Schierloh, Jan Bruining, Margriet Bisschoff, Aleksander Basiak, Renata Wasikowa, Marta Ciechanowska, Grazyna Deja, Przemyslawa Jarosz-Chobot, Agnieszka Szadkowska, Katarzyna Cypryk, Malgorzata Zawodniak-Szalapska, Luis Castano, Teba Gonzalez Frutos, Mirentxu Oyarzabal, Manuel Serrano-Ríos, María Teresa Martínez-Larrad, Federico Gustavo Hawkins, Dolores Rodriguez Arnau, Johnny Ludvigsson, Malgorzata Smolinska Konefal, Ragnar Hanas, Bengt Lindblad, Nils-Osten Nilsson, Hans Fors, Maria Nordwall, Agne Lindh, Hans Edenwall, Jan Aman, Calle Johansson, Margrit Gadient, Eugen Schoenle, Dorothy Becker, Ashi Daftary, Margaret Franciscus, Carol Gilmour, Jerry Palmer, Rachel Taculad, Marilyn Tanner-Blasiar, Neil White, Uday Devaskar, Heather Horowitz, Lisa Rogers, Roxana Colon, Teresa Frazer, Jose Torres, Robin Goland, Ellen Greenberg, Maudene Nelson, Holly Schachner, Barney Softness, Jorma Ilonen, Massimo Trucco, Lynn Nichol, Erkki Savilahti, Taina Härkönen, Mikael Knip, Outi Vaarala, Kristiina Luopajärvi, Hans-Michael Dosch
-
- Journal:
- Public Health Nutrition / Volume 17 / Issue 4 / April 2014
- Published online by Cambridge University Press:
- 24 June 2013, pp. 810-822
-
- Article
-
- You have access Access
- HTML
- Export citation
-
Objective
To examine the use of vitamin D supplements during infancy among the participants in an international infant feeding trial.
DesignLongitudinal study.
SettingInformation about vitamin D supplementation was collected through a validated FFQ at the age of 2 weeks and monthly between the ages of 1 month and 6 months.
SubjectsInfants (n 2159) with a biological family member affected by type 1 diabetes and with increased human leucocyte antigen-conferred susceptibility to type 1 diabetes from twelve European countries, the USA, Canada and Australia.
ResultsDaily use of vitamin D supplements was common during the first 6 months of life in Northern and Central Europe (>80 % of the infants), with somewhat lower rates observed in Southern Europe (>60 %). In Canada, vitamin D supplementation was more common among exclusively breast-fed than other infants (e.g. 71 % v. 44 % at 6 months of age). Less than 2 % of infants in the USA and Australia received any vitamin D supplementation. Higher gestational age, older maternal age and longer maternal education were study-wide associated with greater use of vitamin D supplements.
ConclusionsMost of the infants received vitamin D supplements during the first 6 months of life in the European countries, whereas in Canada only half and in the USA and Australia very few were given supplementation.