Conservation tillage is rapidly being accepted by farmers in the United States because of its advantages over conventional systems. However, there is limited information about its impact on soil organisms, especially nematodes, which play an important role in crop production. Field studies were conducted to determine the effects of tillage system on nematodes after harvest in relation to soil type, crop stand, and crop sequence at two sites in the Lower Rio Grande Valley of Texas (LRGV). In a dry-land site in Willacy Co., neither conventional tillage nor conservation minimum tillage systems affected the numbers of free-living (36 vs 27 nematodes/100cm soil) and reniform nematodes, Rotylenchulus reniformis (2 vs 9 nematodes/100cm soil). Although the number of free-living nematodes (25-42 nematodes/100cm soil) was greater than that of R. reniformis (0-7 nematodes/100cc soil), they were not significantly different among soil types. In contrast, at the irrigated Hidalgo Co. site, higher
