TEXAS A&M AGRILIFE ROLLING PLAINS AGRONOMY PROGRAM

DIVERSIFYING ORGANIC COTTON PRODUCTION IN SEMI-ARID ENVIRONMENTS OF TEXAS

PI: Paul DeLaune

Project summary, goal and objectives

Objective 1 update (September 2022-August 2023)

During year 1 of the study, cotton was the common crop planted across all four crop rotation scenarios. Evaluated scenarios include 1) continuous cotton with a rye cover crop; 2) cotton-sesame rotation; 3) cotton-peanut rotation; and 4) cotton-wheat-annual forage rotation. Rotations 2-4 cover crops of 1) cereal rye planted at 34 kg ha-1; 2) cereal rye planted at 25 kg ha-1 plus 12 kg ha-1 of a 50/50 fenugreek/fennel mix; and 3) 17 kg ha-1 of a 50/50 50/50 fenugreek/fennel mix. The fennel/fenugreek mix is planted in the spring. For this reporting period starting September 2022, the second year of the rotation had been implemented at sites in Lubbock and Vernon, TX. Existing rotations in Fall 2022 included continuous cotton, sesame following cotton, a cover crop/silage mixture consisting of sorghum-sudangrass and forage cowpeas following cotton/wheat, and either peanut (Lubbock) or mungbeans (Vernon) following cotton. At each location, severe weed pressure was a limiting factor to stand establishment and productivity. At Lubbock, insect pressure was detrimental to sesame production. At Vernon, palmer amaranth infestation resulted in two re-plantings. Although the system was clean tilled three times, once before the initial planting and twice before re-planting, weed pressure remained high into the fall. In addition to weed pressure, exceptional drought conditions were experienced at each location. Hay, sesame and mungbeans were harvested at the Vernon site whereas cotton was deemed a failure due to weed pressure. At Lubbock, only cotton was harvested due to a combination of climate, insect and weed pressure. Rye was planted as a cover crop at each location in fall 2022 after respective harvests. The fenugreek/fennel mixture was planted alone or within standing rye cover crop in spring 2023. Rye performed well at each location. In contrast, the fennel/fenugreek mixture did not establish well at either location alone as a cover or interseeded within the rye cover crop. Cotton was planted at each location in late spring/early summer 2023. Stand establishment of organic cotton seed was extremely poor at each location. Seed quality should be considered as an area of concern for future organic research projects as conventional cotton varieties in adjacent plots established well. Cotton was replanted in Vernon in early July, which is well past ideal planting dates. Throughout the reporting period, soil moisture was monitored, and soil samples were collected for soil nutrient and soil health analysis. Cover crops did not significantly reduce soil moisture compared to fallow. Crop rotation resulted in higher soil moisture content compared to continuous cotton throughout the season. Moisture use, weed pressure, cover crop biomass, and crop yields will be correlated with soil health measurements once completed. Various weed management strategies have not been successful to control palmer amaranth, including delayed planting, repeated tillage operations, re-planting, and use of finger weeders.