|Pikul jr, Joseph|
Submitted to: Proceedings Great Plains Soil Fertility Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/14/2002
Publication Date: 5/5/2002
Citation: Riedell, W.E., Pikul Jr, J.L., Carpenter-Boggs, L. 2002. One plus one equals three: the synergistic effects of crop rotation on soil fertility and plant nutrition. Proceedings Great Plains Soil Fertility Conference. March 5-6, 2002. Denver, CO. Vol. 9. Interpretive Summary: Previous studies indicate that under conditions of high soil fertility, nutrient accumulation in corn tissue at physiological maturity, as well as grain yield, were greater in first year corn (after soybean) than in corn grown under monoculture. We were interested in determining if these same results would occur under more complex crop rotations and diverse levels of fagricultural chemical input. The objective of our experiment was to investigate the effects and interactions of complex crop rotations (with legumes in the rotation as hay as well as row crops) and different agricultural chemical input levels on soil fertility and corn mineral nutrient composition. Our experiment included crop rotations and input level treatments that mimicked agricultural production systems used by farmers in the northern portion of the US corn belt. Such a systems approach, which synthesizes scientific inquiry with real world agronomic situations, integrates research results for identification of gaps in our knowledge and improves the probability that experimental results will be applied by farmers to solve problems associated with crop production. Several significant rotation by input level interactions were present. Plots of these data revealed that shoots grown under either 2-yr rotation intermediate input or 4-yr rotation low input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these same input treatments in other rotations. Our data clearly demonstrate the beneficial effect of crop rotation on shoot dry weight and mineral nutrient accumulation in corn. However, the data collected allow only speculation of the actual mechanisms involved in these responses. Further studies will be needed to reach a mechanistic understanding of crop rotations.
Technical Abstract: This study was conducted to determine if complex crop rotations (with legumes in the rotation as alfalfa hay as well as soybean row crops) and different levels of agriculture chemical input affect soil fertility and corn mineral nutrient composition. The effects of crop rotation [monoculture corn, corn-soybean 2-yr rotation, corn-soybean-wheat underseeded with alfalfa-alfalfa 4-yr rotation] and input level [high inpu (fertilizer application for 8.15 Mg ha-1 yield goal, prophylactic herbicide and insecticide application, fall moldboard plow/spring disk and cultivation operations), intermediate input (fertilizer application for 5.33 Mg ha-1 yield goal, pesticide applications based upon pest survey and IPM principles, fall chisel plow/spring disk and cultivation operations), and low input (no fertilizer, herbicide, or insecticide applications, fall chisel plow/spring disk and cultivation operations)] on soil fertility (pH, ,organic matter, NO3-N, P, K, and total N) and on corn shoot dry weight, mineral nutrient (N, P, Ca, Mg) concentration and accumulation were investigated at Brookings, SD. Crop rotation treatments reduced soil pH, increased soil NO3-N level, and decreased soil P level when compared to corn monoculture. Shoots of plants grown under either 2-yr rotation intermediate input or 4-yr rotation no input treatments had greater dry weight, as well as greater P, Ca, and Mg accumulation than these same input treatments in other rotations. These results demonstrate a beneficial effect of crop rotation upon soil fertility and soil mineral nutrition. The results of this experiment are discussed in terms of nutrient synergisms whereby nutrient absorption proceeds at a faster rate than dry weight accumulation.