Maximizing Irrigated Soybean Yields in the Great Plains
Several years of irrigated field research in north central Kansas clearly demonstrated the importance of complete and balanced nutrition in the production of high yield corn (Gordon, 2005). However, fertilization of soybeans in a common corn/soybean rotation has traditionally been secondary to corn fertilization, as the crop is usually left to scavenge nutrients remaining after corn. This study was started in 2004 as an expansion of the original corn research to determine the benefit of direct fertilizer application to sprinkler irrigated soybeans. It has shown that the addition of P and K can have a significant impact on soybean yield, with 4-year average increases due to P and K as high as 34 bu/A. This experiment also demonstrated that Mn can impact soybean production in high yielding environments.
Maximizing Irrigated Corn Yields in the Great Plains
There is a large gap between attainable corn yields and present average yields. The overall objective of this north central Kansas work is to find practical ways of narrowing this gap. Two plant populations and two nutrient input levels were evaluated. With low fertility inputs, yields were decreased when population increased. However, corn produced significantly greater yield at the higher population with additional fertility inputs. One-third of the response to additional nutrient inputs was lost if plant density was not increased. This work further illustrates the importance of using a systems approach when attempting to increase yield levels.
Potassium is important in optimizing both crop yield and economic quality. Root activity and K uptake are generally reduced during the reproductive phase of crop development. This article details a Rio Grande Valley study that has shown that supplementing soil K with additional foliar K applications during cantaloupe fruit development and maturation improves fruit marketable quality by increasing firmness and sugar content, and fruit human health quality by increasing ascorbic acid, beta-carotene, and K levels.
