Economic and agronomic effects of four tillage practices on rice produced on saline soils

Conservation tillage practices have come into greater use in recent years. However, studies have shown that using these practices in rife (Oryza sativ a L.) on soils prone to salinity problems can reduce yields. An agronomic s tudy was conducted during 1995 and 1996 at the University of Arkansas' Pine Tree Branch Experiment Station near Colt on a soil complex consisting or a Calloway silt loam (fine-silty, mixed, active, thermic Glossaquic Fragiuda lf), Calhoun silt loam (fine-silty, mixed, active, thermic Typic Glossaqual f), and Henry silt loam (coarse-silty, mixed, active, thermic Typic Fragiaq ualf), in areas that had a history of salinity damage to rice. The experime nt was arranged in a randomized complete block design with three replicatio ns and four tillage treatments (conventional tillage, deep tillage with a p aratill implement, attempted deep tillage with a chisel plow, and no-till) per replication. Enterprise budgets were used to determine the relative pro fitability of the four tillage systems (conventional, no-till, chisel plow, and pare-till), in order to determine whether or not the increased product ion costs incurred using tillage would be offset by increased returns. Sens itivity, breakeven, and statistical analyses were performed to determine wh ether there was any significant difference in yields and net returns among tillage practices. No significant difference was demonstrated among the thr ee treatments using tillage; no-till, however, was significantly different from the other three, having considerably lower yields. When averaged acros s years and treatments, yields from tilled plots averaged 72.15 cwt/acre. Y ields from no-till plots averaged 62.37 cwt/acre. Net returns above total c osts for tilled plots, when averaged across years and treatments, averaged $230.25/acre. Net returns above total costs for no-till averaged $173.03/ac re. It is therefore recommended that some form of tillage be used in order to reduce the concentration ol salts in the rice root zone. However, it is not possible to recommend one form of tillage as being superior to the othe rs examined in this study.