Cropping System Effects on Cotton Variety Performance in the Presence of Root-Knot Nematodes in the Southern High Plains of Texas

The Southern High Plains of Texas (SHPT) is the largest cotton producing region in the world. Water is one of the greatest limiting factors of production for the region, prompting producers to explore more water-efficient production strategies. Furthermore, root-knot nematodes (RKN) negatively affect lint yields and are extremely prevalent in the SHPT. While considerable research has been conducted on crop rotations and RKN partially resistant cotton varieties, little research has investigated a crop rotation, irrigation rate, and cultivar that maximizes profit in the presence of RKN on the SHPT. Thus, the objective of this study was to determine if a cotton-wheat rotation paired with a RKN partially resistant cotton variety was more profitable compared to a continuous cotton system utilizing the same cultivars. Moreover, variable irrigation rates were utilized on both systems to analyze lint yield and profitability differences. Data from a multi-year study from 2014-2019 in the SHPT were compared to evaluate irrigated conventional tillage practices with terminated rye cover crop versus an irrigated wheat-cotton rotational system with multiple cotton varieties, one which was partially resistant to RKN. Partial budgets were constructed to analyze profitability differences between the two cropping systems and different cotton varieties. Results indicate that the partially resistant variety was the most profitable overall in both systems for the six-year period and performed best in the presence of RKN. The cotton-wheat rotation suppressed RKN presence and had greater returns per acre-inch of irrigation water applied during the cotton segment of the rotation.