Utilization of MSW Compost and other Organic Mulches on Commercial Vegetable Crops

Increased availability of commercially derived composts and problems with disposal of polyethylene mulch are factors which precipitated an investigation of the long term effects of organic and polyethylene film mulches on soils, plant growth, and yields. Three experiments were performed comparing polyethylene film mulch (PM) with mulches of commercial municipal solid waste compost (MW), dried sewage sludge (SS) and wood chips (WC). In 1990, bell pepper (Capsicum annum L.) plants on PM yielded 8.9 t'ha“1, which was significantly higher than the 1.9,4.6, and 7.2 t•ha−1 produced at MW compost rates of 13, 40 and 121 t•ha−1, respectively. Yields increased linearly with increasing rates of compost mulch. In spring, 1992, each organic material was applied at 224 and 336 t•ha−1 and winter (spaghetti) squash (Cucurbita pepo L.) was seeded. Soil moisture was higher under organic mulches than under PM. Soil temperatures in the mornings were not significantly different among mulches, but in the afternoons: SS>PM>MW>WC. Plants grown on PM had larger shoots and roots and produced more fruit per plant, but, because of plant losses to disease, had lower total yields than plants grown in MW and WC. Higher soil Na content occurred in MW plots and high electrical conductivity (EC) occurred in soils of SS plots. In fall, 1992, bell peppers transplanted into the same plots produced 4.7, 4.5, 3.3, and 2.7 t•ha−1 from PM, MW, WC, and SS, respectively. Soil tests detected higher NO3-N in WC plots, higher K in PM, higher Zn in MW, and lower Mn and higher Mg in SS plots, than in other treatments. Vegetables grown on PM produced higher fruit yields than those on organic mulches, however, plant losses to disease were also highest in PM plots. Environmental and economic considerations and governmental regulations may encourage organic mulch utilization by commercial vegetable growers.