MUNICIPAL SOLID-WASTE COMPOST IN IRRIGATED VEGETABLE PRODUCTION

An improvement in the water- and nutrient-retention properties of a sa ndy soil by amendment with an organic medium could improve the managem ent difficulties associated with drip irrigation on these soils for pl ants with Limited root systems. Municipal solid waste compost (MSWC) w as incorporated into experimental field plots in June 1992 for evaluat ion as a soil amendment in both drip-irrigated and subirrigated vegeta ble production systems. Application levels for MSWC were 0, 67, and 13 5 t ha(-1) in the drip-irrigated plots and 0 and 135 t ha(-1) in the s ubirrigated plots. Fall (1992) peppers and spring (1993) tomatoes were evaluated for yield in the MSWC and control plots at 0.5X, 1X and 1.5 X levels of applied water (1X based on crop needs as determined by the Penman method); at 213 and 306 kg N ha(-1) in the drip-irrigated plot s; and at 213, 306, and 400 kg N ha(-1) in the subirrigated plots. Yie lds of peppers were reduced by application of MSWC, due to immaturity of the compost product upon field incorporation. Irrigation level only affected early yield of drip-irrigated tomatoes, and applied fertiliz er level did not affect subirrigated tomato yields. However, drip-irri gated spring tomato yields were increased in the MSWC plots and increa sed with additional fertilizer compared to the control plots. Yield of extra-large fruit in the subirrigated plots also increased with MSWC.