Evaluation of Soil Amendments for Lettuce Production in the Desert

摘要

Two field studies were conducted during the 1993-1994 season to evaluate the response of lettuce to soil applied amendments. Treatments included gypsum, polymaleic acid (Spersal), and two acid products (N-phuric and Phos-phuric). Gypsum rates (0, 2240, and 4480 kg /ha) were the main plots and other soil amendments were subplot randomized within the mainplots. Overall, gypsum reduced early growth and vigor of lettuce. Gypsum had no effects on marketable yield and quality parameters in experiment 1, but the highest gypsum rate (4448 kg /ha) decreased marketable yield in experiment 2. There were no differences in plant stands due to subplot treatments. However, there were differences in earlygrowth and vigor. In experiment 1, both "N-phuric" and "Phos-phuric" increased early lettuce growth compared to the control. In experiment 2, Phos-phuric was superior to N-phuric. In experiment 1, the benefits of early growth and vigor to the "N-phuric" and "Phos-phuric" carried to harvest where marketable yield and quality were significantly increased. Spersal did not significantly effect yield and quality of lettuce in either experiment.