|Terra, J - AUBURN UNIVERSITY|
|Shaw, J - AUBURN UNIVERSITY|
|Van Santen, E - AUBURN UNIVERSITY|
|Mask, P - AUBURN UNIVERSITY|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 7, 2003
Publication Date: May 12, 2003
Citation: Terra, J.A., Reeves, D.W., Shaw, J.N., Raper, R.L., Van Santen, E., Mask, P.L. 2003. Spatial variation of cotton yield: influence of soil management and terrain attributes. National Cotton Council Beltwide Cotton Conference. Interpretive Summary: A better understanding of field variability is needed by producers to optimize inputs and maximize yields and profits. We evaluated cotton yield response to soil management practices and their interactions with landscape and soil features in a field-size experiment in east-central Alabama. Soil survey, geo-referenced elevation, and electrical conductivity were used to map field variability. Two soil management systems, with and without annual application of dairy manure, were stripped across the field in a corn-cotton rotation. Systems included a conventional system (chisel plowing and no winter cover crop) and a conservation system (no-till) with legume and small grain covers. Conservation system yields, regardless of manure application, averaged 2,174 lb lint/acre. Conventional system yields averaged 1949 lb/acre with manure and 1841 lb/acre without manure. In addition, yield variability was reduced with the conservation system, and this system had greater impacts in a dryer year and in areas in the field (zones) with lower yield potential. Electrical conductivity, slope, soil texture and elevation explained between 15 to 60% of yield variability. However, simple subjective terrain feature information was also effective in identifying areas of variability, suggesting that economical methods of mapping yield variability in fields can improve efficiencies of inputs. This information can be used by extension, NRCS, and private-sector consultants to promote the use of conservation systems that optimize inputs and profits for cotton production.
Technical Abstract: Soil management practices are rarely assessed at the landscape level. We evaluated cotton (Gossypium hirsutum L.) yield response to soil management practices and their interactions with landscape and soil attributes in a 24 acre trial in east-central Alabama in 2001 and 2002. A soil survey, geo-referenced elevation, and electrical conductivity maps were developed for delineating field variability. A factorial arrangement of two soil management systems with and without annual application of dairy manure was evaluated in a corn (Zea mays)-cotton rotation. Treatments were: a conventional system (CT), a conventional system + dairy bedding manure (CTM), a conservation system (NT) and conservation system + manure (NTM). Conventional systems included chisel plowing/disking + in-row subsoiling and no cover crop. Conservation systems included in-row subsoiling and winter cover crops of a white lupin (Lupinus albus L.)/crimson clover (Trifolium incarnatum L.) mix prior to corn and a black oat (Avena strigosa Schreb.)/rye (Secale cereale L.) mix prior to cotton. Treatments were established in 20-ft wide strips intercepting landscape variability in a RCB design with six replications. No-till and NTM yields (2182 and 2159 lb acre-1) were higher than CTM (1949 lb acre-1). Lowest yields occurred with CT (1841 lb acre-1). The coefficient of variation was greater in conventional systems (13.4%) compared to conservation systems (10.8%). Electrical conductivity, slope, soil texture and elevation explained between 15 to 60% of yield variability but simple subjective terrain attribute information was similarly effective in delineating variability. The conservation system had greater impacts in the dryer year and in zones with lower yield potential.