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Abstract
Slow-release N sources (sewage sludge, Agriform, Osmocote, sulfur-coated urea (SCU) and isobutylidene diurea (IBDU)) and a soluble N source (ammonium sulfate) were applied to soil at the rates of 224 and 448 kg N/ha before planting bermudagrass (Cynodon magenisii Hurcombe cv. Sunturf). Yield, % N, and N recovery at 3 cuttings at 30 day intervals were significantly higher at the 448 kg/ha rate than at the 224 kg/ha rate and were highest in the first of 3 cuttings and decreased significantly in the second and final cuttings. The slow-release N sources, except Agriform, generally gave higher yield, % N, and N recovery values than ammonium sulfate, especially at the third cutting and at the higher N rate. Osmocote, SCU and IBDU generally gave higher values than sewage sludge and Agriform.
Abstract
Papaya plants, Carica papaya L. cv. Solo, were treated with 3 levels of lime combined with 3 levels of P in a split-plot arrangement. Optimal yield of papaya was maintained when the pH of the surface soil ranged from 5.5 to 6.7. Liming lowered petiole concentrations of Mn, K, and Mg and raised those of Ca and P; petiole P was raised when P was applied only. Phosphorus fertilization increased the growth rate of the tree-trunk circumference only at the early stage of growth, while liming affected growth later than P. Phosphorus fertilization raised the petiole concentrations of P, N, Mn, and Zn and lowered petiole concentrations of K and Cu.