تجزیه و تحلیل اقتصادی بدون خاک ورزی و با حداقل خاک ورزی چرخش پنبه ذرت در دلتا می سی سی پی

Crop rotations have been shown to have agronomic benefits. An increasingly common crop rotation in the Mid-South is cotton rotated with corn. Many previous studies have focused on tillage systems or crop rotations. Few have evaluated a combination of the two (crop rotations and tillage) especially from an economics perspective. Field studies were conducted at Stoneville, MS for the period 2001–2006. Treatments included no till continuous cotton, minimum till continuous cotton, one year corn followed by two years cotton no till, one year corn followed by two years cotton minimum till, one year corn-one year cotton no till and one year corn-one year cotton minimum till. Results revealed that cotton yields were increased in all four systems rotated with corn. Lower risk was associated with minimum till cotton. Gross returns were higher in a monoculture minimum till cotton system. Net returns were larger in a system that included minimum tillage and a corn rotation. The highest net returns and lowest risk were obtained from a minimum till system of cotton rotated with corn every other year. For those producers required to use a no till system, a one year corn-two year cotton rotation provided the highest net returns and least risk.

Crop rotations have been shown to have agronomic benefits for several years (Spurgeon and Grissom, 1965; Kurtz et al., 1987; Ebelhar and Welch, 1989; Bechel et al., 2000). An increasingly common crop rotation in the Mid-South is cotton rotated with corn. In addition to the agronomic benefits, crop rotations are often considered for the economic benefits as well. The recent interest in ethanol production as a result of high petroleum prices has led many producers to consider corn as an alternate crop. Previous studies have suggested cotton produced the first year after a corn crop to have yield advantages as high as 12% compared to continuous cotton and a 6% increase in yield for cotton the second year after a corn crop (Martin et al., 2002). Additionally, the aforementioned increases in fuel prices have renewed interest in reduced tillage systems previously considered for conservation reasons but now considered for economic reasons as well. Cotton production in some areas has switched to no till and/or conservation tillage due to mandates associated with highly erodible soils. Other cotton growing areas have begun using less tillage as a means to cut production costs. Conventional farming methods (sub-soiling, disking, cultivating, etc.) often require 7–10 trips across the field for field preparation and weed control (Delta Planning Budgets, 1999). As production costs have risen (diesel fuel in 1999 was $0.64 per gallon versus $2.41 in 2007, [Delta Planning Budgets, 1999 and Delta Planning Budgets, 2007]), producers have sought alternative methods to produce cotton. Previous studies have focused on tillage systems or crop rotations. Few have evaluated a combination of the two (crop rotations and tillage) especially from an economics perspective. This study evaluates and compares two tillage systems (no till and minimum till) in combination with three cropping systems (continuous cotton, two years cotton following a corn crop and a one year cotton-one year corn rotation).

Six tillage-crop rotation systems were evaluated based on net returns and risk over a six-year period in the Mississippi Delta. Cotton yields were increased in all four systems rotated with corn as compared to monoculture cotton. Lower risk was associated with minimum till cotton in a monoculture system. Gross returns were higher in a monoculture minimum till cotton system, followed by a no till monoculture cotton system. Net returns, however, were larger in a system that included minimum tillage and a corn rotation. Results indicated that the highest returns and lowest relative risk were obtained from a minimum till system of cotton rotated with corn every other year. For those producers required to use a no till system, then a corn crop followed by two years cotton production provided the highest net returns and the lowest risk