Search Filter
- Publications
- Abstract of Theses and Dissertations
- Database
- Effects of Nitrogen, Phosphorus and Sulfur Fertilization on Growth...
Effects of Nitrogen, Phosphorus and Sulfur Fertilization on Growth, Yield and Protein Components of Bush Sitao (Vigna sesquipedalis Fruw.)
Thesis Abstract:
Results of the pot experiments showed that growth and yield of bush sitao were significantly improved by the addition of phosphorus and only slightly by nitrogen or sulfur alone. Much better yields were obtained from combined nitrogen and phosphorus application; with or without sulfur, on bot Guadalupe clay and San Manuel sandy loam.
Chemical analyses indicated that applied nitrogen, phosphorus or sulfur increased their respective concentration in the plants. Combination of nitrogen and phosphorus increased nitrogen, phosphorus and sulfur concentrations in plant parts, but sulfur added to nitrogen and phosphorus lowered phosphorus concentrations.
Protein nitrogen and protein sulfur increased with increasing phosphorus level in combination with nitrogen. Nitrogen alone significantly increased nonprotein nitrogen bot not protein fractions. In contract, added sulfur increased protein nitrogen and protein sulfur but decreased the nonprotein fractions (amino acids, amides, ammonium and nitrate nitrogen). The beneficial effects of phosphorus on the conversion of absorbed nitrogen and sulfur to protein forms were manifested in bush sitao grown on both soil types.
Addition of either phosphorus alone or with nitrogen markedly increased sulfur content of the soils. Phosphorus increased the carry-over level of phosphorus but slightly decreased those of nitrogen and sulfur. Generally, however, the nitrogen, phosphorus and sulfur contents of both Guadalupe clay and San Manuel clay learn after cropping were higher than the original levels.