| Summary: | 碩士 === 國立臺灣大學 === 農業化學研究所 === 89 === Appropriate use of organic and chemical fertilizers is not only necessary for maintaining good physical , chemical and biological characteristics of soils but also for sustainability of the soils. Owing to the environmental concern of pollution, the importance of organic farming is attached gradually. Therefore, a field experiment to study the effect of long-term application of fertilizers was set by Council of Agriculture in Chishan Town from 1988. The trial included six treatments with the combinations of three cultivation methods and two rotation systems. The three cultivation methods were organic farming (OF), conventional farming (CF), and intermediate farming (IF). Two rotation systems were designed to contain a conventional rotation crops and a suggested better rotation crops. The effects of different rotation systems and fertilization management on the growth, nutrient uptake of crops were investigated in this study. The summer crop in 1999 was paddy rice in both rotation systems, the spring crops in 2000 were corn in rotation system I and paddy rice in rotation system II. Sesbania followed spring crops. Paddy rice plants were sampled at most active tillering , full heading, and maturity stages. Corn plants were sampled at tasseling and maturity stages. Sesbania was sampled on 52 and 70 days after seeding. The plant samples were separated according to the different organs, dried to constant weight at 65℃, and grounded, the concentrations of total nitrogen, nitrate nitrogen (NO3--N), ammonium nitrogen (NH4+-N), soluble organic nitrogen, insoluble nitrogen , phosphorus (P) , potassium (K) , calcium (Ca), magnesium (Mg) , iron (Fe) , manganese (Mn) , copper (Cu), and zinc (Zn) were analyzed.
The results indicated that t he yield of summer rice of OF treatment in rotation system I and of IF treatment in rotation system II in 1999 were significantly higher than those of the CF treatment in the two rotation systems. However, the total dry matter yield of CF treatment of spring rice in 2000 was higher than that of the OF treatment. There was no significant difference in the yield of spring corn among the treatments. The yield of sesbania of IF treatment in rotation system I and of OF treatment in rotation system II were significantly higher than those of the other treatments. The amounts of N uptake by summer rice and spring corn of CF treatment in rotation system I were higher than those of the other treatments, however, the amount of N uptake by sesbania of OF treatment was higher. The N concentrations in various parts of rice and corn plants of CF treatment in rotation system I were higher than those of the other treatments. In rotation system II, the amounts of N uptake by summer rice and sesbania of CF treatment were the lower of the treatments, however, the amount of N uptake by spring rice was higher than those of the other treatments. The N concentrations in various parts of rice and sesbania plants of CF treatment in rotation system II were higher than those of the other treatments. The concentrations of insoluble N, which was the highest proportion of N composition, in various parts of plants of CF treatment were higher than those of the other treatments. However, there was no significant difference in NO3--N, NH4+-N and soluble organic N concentrations in the plants of various treatments. The amount of P and K uptake by rice plants of CF treatment was higher than those of OF and IF treatments, however, the amounts of P and K uptake by corn and sesbania of CF treatment were lower than those of IF and OF treatments. There was also no significant difference in Ca and Mg uptake by rice, corn and sesbania among treatments. There was no significant difference of concentrations of Ca, Mg, Fe, Mn, Cu and Zn in plant organs at different growth stages between different treatments, except the concentrations of Fe and Mn of summer rice and sesbania.
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