[PDF] Rotational And Residual Nitrogen Effects On Soybean And Corn eBook

Author : Andy Clark
Publisher : DIANE Publishing
Page : 248 pages
File Size : 40,17 MB
Release : 2008-07
Category : Technology & Engineering
ISBN : 1437903797

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Cover crops slow erosion, improve soil, smother weeds, enhance nutrient and moisture availability, help control many pests and bring a host of other benefits to your farm. At the same time, they can reduce costs, increase profits and even create new sources of income. You¿ll reap dividends on your cover crop investments for years, since their benefits accumulate over the long term. This book will help you find which ones are right for you. Captures farmer and other research results from the past ten years. The authors verified the info. from the 2nd ed., added new results and updated farmer profiles and research data, and added 2 chap. Includes maps and charts, detailed narratives about individual cover crop species, and chap. about aspects of cover cropping.

Author : Donald Sanders
Publisher :
Page : 0 pages
File Size : 18,26 MB
Release : 2017
Category :
ISBN :

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Sanders, Donald W. The University of Manitoba, March, 2017. The effect of preceding crop on soybean (Glycine max) grain yield, mycorrhizal colonization, and biological nitrogen fixation. Major Professor:Yvonne Lawley. Manitoba has seen a twenty-fold increase in soybean acres seeded since 2000, with over 1.6 million acres seeded in 2016. This change presents unique opportunities and challenges to improve crop rotations in Manitoba. This experiment studied the effect of four crop sequences on soybean yield, mycorrhizal colonization, and biological nitrogen fixation. In the first year of this experiment, spring wheat, canola, corn and soybeans were grown at three sites in Manitoba (Carman, Portage la Prairie, and Kelburn). In the second year, soybeans were grown on these same plots as a test crop. This two-year sequence of crops was done twice at each site, in 2012-13 and 2013-14. To determine mycorrhizal colonization, root samples were collected at the V3 stage and then analyzed microscopically for mycorrhizal infection. Nitrogen fixation was estimated using the natural abundance method using soybeans collected at the R5 and R6 stage and canola as a reference crop. Soybean following soybean had significantly higher grain yield than all other crop sequences at one site year, and significantly lower grain yield than all other crop sequences at another site year. There were no other differences in soybean test crop yield between crop sequences. Crop sequence significantly affected mycorrhizal colonization. Soybean following canola had significantly lower mycorrhizal colonization than soybean following soybean or corn. Soybean following spring wheat also had significantly lower mycorrhizal colonization than soybean following soybean or corn. Soil test phosphorus levels also significantly affected mycorrhizal colonization, with increasing soil phosphorus resulting in decreased mycorrhizal colonization. Crop sequence significantly affected biological nitrogen fixation. Soybean following soybean or corn often had significantly greater biological nitrogen fixation than soybean following spring wheat or canola. Soil test nitrate levels affected biological nitrogen fixation, with increasing soil nitrate resulting in decreased biological nitrogen fixation. Soil test nitrate levels were affected by the carbon to nitrogen ratio of the preceding crop, with a higher carbon to nitrogen ratio associated with decreased soil nitrate. These results indicate that although there is often not a yield penalty associated with specific rotations, crop sequence has a strong impact on mycorrhizal colonization and biological nitrogen fixation. The soil organisms associated with those processes affect soil phosphorus uptake and nitrogen fixation. Producers should consider the importance of crop rotation when seeking to maximize productivity through symbiotic processes with mycorrhizae and nodule forming bacteria.