According to the study by Han et al. (2005) in Zhaoguang Farm, which was the first mechanical farm built in Heihe city in late 1950s, the vegetation has changed from natural vegetation to cropweed, to rotation of corn-soybean-wheat, or to rotation of corn-soybean.
The 19-year experiment conducted from 1990 to 2008 involved seven treatments designed: cropping rotation of soybean-corn-corn with no fertilizer (control, CK), recycled manure (RM), fertilizer nitrogen (N), phosphorous (P) and potassium (K) (NPK), NPK+RM, and no-crop bare land, mowed fallow, and non-mowed fallow.
The common Midwestern rotation of HR corn-HR soybeans, or HR soybeans-HR cotton in the South, exposes weed populations to annual and repetitive glyphosate-selection pressure.
Transferring his feet from one patch of old-fashioned hay mulch to the next, he watched his steps so carefully that he missed much of Enoch's friendly lecture on crop rotation, and on new varieties of corn that didn't take so much nitrogen out of the soil.
Therefore, O'Neal et al. (2004) proposed a behavioral plasticity model for rotation resistance, in which early senescence of corn because of early planting repels adult beetles from corn fields, and no genetic change has occurred in beetle populations.
Davis et al. [95] showed in a nine-year field study in the US corn belt that more diverse rotations including forage legumes enhanced yields of corn and soybean grain by up to 9% and reduced fertilizer application, energy use, and herbicide input significantly.
Consequently, we believe that as the corn stover is driven forward and compressed by the plug screw feeder, the material within the rotating flights separates from the fraction packed within the anti-rotation device, causing the forward movement of corn stover to slow or halt.
The only crop plant on which larvae can survive is corn, so yearly rotation of crops (i.e., annual alternation of corn with another crop in the same field) has been a major control method.
Therefore, increasing the frequency of corn plantation in the corn and soybean rotation system or replacing it with continuous corn would significantly lead to more nitrate to waterways and decrease soil nitrogen content (Wu et al. 2014; Wu and Liu 2012).
The study utilized a complete factorial design with four replications of the following factors: Rotation: continuous biomass sorghum vs. biannual rotation with corn (Zea mays L.); Stover Return: 0, 250%50% of the sorghum biomass and all corn stover; and N Rate: 0 vs. non-limiting N. The bioenergy sorghum used was a high-yield photoperiod-sensitive hybrid.
