Cover Crops and Tillage Effects on Cotton

Cotton ( Gossypium hirsutum L.) is one of the most erosive row crops grown in the southeastern USA and with the implementation of the 1985 Food Security Act, producers may have to use no‐till or cover crops in order to remain in compliance. A 3‐yr field experiment examined cover crop (crimson clover [ Trifolium incarnatum L.], hairy vetch [ Vicia villosa L.], wheat [ Triticum aestivum L.], and cool season weeds) and tillage (no‐till [NT] and conventional [CT]) effects on cotton. Wheat produced more canopy cover during the winter and higher dry matter (DM) yields during 2 of 3 yr than the other winter vegetation. Seedcotton yields for NT cotton were significantly higher than for CT cotton during 1 yr of this study. Generally, plant height and population were unaffected by cover crops or tillage treatments. Stem, leaf, and total plant weights were significantly higher for NT cotton in 1 of 2 yr. Cone index readings at the 6‐in. depth were significantly greater for NT cotton at in‐row and traffic middle sites. Soil pH and organic matter percentage were generally unaffected by cover crops or tillage systems. Extractable P levels (0‐ to 3‐in. depth) tended to be higher for NT cotton while extractable K amounts (0‐ to 3‐in. depth) tended to be higher for CT cotton. Total production expenses across cover crops were lower for NT cotton than for CT cotton. Of the planted cover crops, wheat was the least expensive to establish. No‐till cotton, therefore, could be used to reduce soil erosion while maintaining high cotton yields. Research Question Major row crops such as corn, grain sorghum, and soybeans have responded favorably to conservation tillage and cover crops. However, producers have been slow to adopt conservation tillage practices for cotton. This research was conducted to evaluate the effects of no‐tillage and cover crops on cotton plant growth, development, and yield. Literature Summary With the implementation of the Food Security Act, producers may have to use alternative production practices in order to remain in compliance. Previous research has shown that conservation tillage will significantly decrease soil erosion in cotton. Little information is available, however, on how conservation tillage and cover crops affect cotton plant production. Study Description Two tillage treatments and four cover crops were evaluated from 1988 to 1991 at the Jamie L. Whitten Plant Materials Center near Coffeeville, Mississippi. Soil type: Grenada silt loam. Experimental design: Randomized complete block in a split plot arrangement. Tillage treatments: Conventional: disk twice, chisel, harrow, cultivate once. No‐till. Cover crops: crimson clover, hairy vetch, wheat, cool season weeds. Applied Question How do no‐tillage and cover crops affect cotton? Cotton produced significantly higher seedcotton yields during 1 of 3 yr under the no‐tillage treatment (Table ). During 2 yr, planting was delayed past the last recommended planting date due to excessive soil moisture in the conventionally tilled plots. No consistent trend occurred for plant height or population relative to tillage or cover crop. No‐till cotton plant components tended to have heavier weights during the first year of this study. Seedcotton yield, plant height, and plant population as affected by cover crop and tillage treatment, 1989–1991. Seedcotton yield Height Population 1989 1990 1991 1989 1990 1991 1989 1990 1991 ‐‐‐‐‐‐‐‐‐ lb/acre ‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐ in. ‐‐‐‐‐‐‐‐‐ × 1000/acre Cover crop Crimson clover 1538 2767 ‐‐ 46 40 ‐‐ 60.2 28.7 ‐‐ Hairy vetch 1556 3022 2041 46 43 38 61.2 27.2 44.6 Wheat 1715 2746 2092 44 38 37 54.4 30.5 45.4 Cool season weeds 1741 2491 1950 43 36 37 57.0 28.9 37.7 Tillage means Conventional 1370 2828 1872 41 39 38 62.8 29.4 33.8 No‐till 1905 2685 2185 48 39 37 53.6 28.3 51.3 LSD (0.05) Cover crop NS NS NS NS 4 NS NS NS NS Tillage 291 NS NS 2 NS NS 7.8 NS 11.0