Residue management and cultural practices for a semiarid region

ABSTRACT:

Two types of residue management and cultural practice schemes for soil and water conservation in the Southern High Plains were evaluated: (a) use of applied mulches and residue grown in-place in the blank rows of a planting pattern of two rows of cotton alternated with two blank rows and (b) use of perennial plants as wind barriers atop small, parallel terraces. The test results were as follows: (1) 7 metric tons per hectare (3 tons/acre) of cotton gin trash and 10 metric tons per hectare (4.5 tons/acre) of millet residue applied as mulches to the blank rows of a 2 × 2 pattern in 1982 increased cotton lint yields 53 kilograms per hectare (47 pounds/acre) (24%) and 161 kilograms per hectare (144 pounds/acre) (90 %), respectively. Additional quantities of either mulch did not significantly increase lint yields. (2) Growing either millet or pigweeds in the blanks of a 2×2 pattern in 1982 reduced lint yields drastically and by essentially the same amounts, regardless of whether the millet and pigweeds were mowed two, four, five, or six times from June 29 through September 15. Lint yields of plants adjacent to the millet and pigweed plots were reduced by an average of 125 kilograms per hectare (112 pounds/acre) (69%) and 182 kilograms per hectare (162 pounds/acre) (93%), respectively. All millet and pigweed plots, except those that had been mowed after July 27, had enough residue on February 10, 1983, to prevent wind erosion. (3) A 70-centimeter-wide (27.5-inch-wide) band of the native grass Texas panicum produced enough residue in 1982 to keep soil losses in the adjacent 17 meters (56 feet) below 11 metric tons per hectare per year (5 tons/acre)—if the erosive winds are perpendicular to the band of grass. (4) Single rows of Ermelo lovegrass and Kleingrass Sel. 75 atop small, parallel terraces spaced 19 meters (62 feet) apart did not significantly affect lint yield of cotton grown between the terraces. A single row of Aztec Maximilian sunflower, however, reduced lint yields 38 percent. Also, the two grasses produced relatively dense barriers and would adequately protect the 19-meter interval from erosion by perpendicular winds. On the other hand, the less dense sunflower barrier would probably adequately protect no more than a 12-meter (40-foot) interval.