Study On Nutrient Limiting Factor And Nutrition Regulation Of Sweet Pepper In Acidic Garden Soils

The systematic approach for determination soil nutrients, using chemical analysis in laboratory, experiment of adsorption, cultivating in greenhouse and field, which was presented first by Hunter (1980) and modified by Sam Porch (1988), was adopted to study the nutrient limiting factor (NLF) and nutrition specific from two indicator plants (sorghum and sweet pepper) in strong acidic (pH4.0, Si), acidic (pH5.0, 52) and slight acidic (pH6.3? 6.4, 53 and 54) garden soils, and the effect of fertilization on the growth and physiology, biomass, yields, nutrition specific of leaf, quality and economic benefit of sweet pepper under two cultivating pattern (greenhouse and field experiment). The research results indicated that: The contents of organic substance were very low (less than 10 glkg) in the four acidic garden soils. And the contents of nitrogen (N), phosphorus (P) (except Si), potassium (K), and sulfur (5) (except 52) were severely deficient, but the contents of calcium (Ca) were extremely abundant, and for magnesium (Mg) and boron (B) were rather plenteous. In acidic and strong acidic soils, the contents of iron (Fe) and manganese (Mn) were higher, however, the contents of copper (Cu) and zinc (Zn) were deficient on the whole. The larger capacity of adsorption and fixing were belonging to K, Zn and Cu in S3 and S4 and to P and B in S2. The fixing capacity of P and Zn in S~ was weak. Not all the NLF of the two indicator plants were identical, however, the NLF of one indicator plant were similar in the same acidic garden soils to a certain extent. For sorghum as the indicator plant, the NLF were phosphorus and nitrogen in Si, boron, phosphorus, copper, and nitrogen in 52, and boron and nitrogen both in 53 and S4. When sweet pepper was the indicato, the NLF were phosphorus and sulfur (in Si), boron, phosphorus, molybdenum, zinc, iron and potash (in 52), boron and potash (in S3), boron and phosphorus (in S4) respectively. The same NLF was nitrogen for sorghum, but phosphorus (except 53) and boron (except Si) for sweet pepper in the four soils. Boron was the same NLF both for sorghum and sweet pepper in S2. 53 and S4. The nutrient contents of sweet pepper were higher than sorghum in the greenhouse experiment. The difference of nutrient contents between higher and lower biomass treatments was not remarkable. As the nutrient rate of higher biomass were considered as the standard values, most of the nutrient rate of lower deviated the range of standards above-mentioned. The adsorption contents of nitrogen in S2 were more great than S, and S1 than S3, just as it was similar with the change of biomass in greenhouse experiment, the adsorption contents of phosphorus were not notable in the soils except that the adsorption contents in 53 were a bit higher, and the adsorption contents of potassium in S, and S2 were higher than 53, but, the former two it was almost equal. The trait of adsorption contents of sweet pepper was not alike contrary with sorghum, as the adsorption contents of the three elements (N, P, K) in 53 were greater than 54, than 52, and than S1 serially, for the former indicator plant. The biomass yield treatments in S were more excessive than 52, and S2 than SI, the values of higher were 1.548?.19l g/pot, l.l24-4.739gIpot, 0.631-4.1.950 g/pot in the three soils respectively. The primary feature of fertilization were potash and nitrogen, and secondly phosphorus in S1, boron firstly and phosphorus secondly in S2, and the combine applying of nitrogen and phosphorus...