The Effects of Different Organic Fertilizers' Application Rates on the Soil Quality and the Production of Pak-Choi and Water Convolvulus

• Main Authors: Shu-Mei Tsai, 蔡淑玫
• Other Authors: Chong-Ho Wang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/66406415825843451326

碩士 === 國立屏東科技大學 === 農園生產系所 === 97 === The objectives of this study were to evaluate the effects on soil quality and the production of both Water Convolvulus and Pak-Choi based on the different application rates of various organic fertilizers. In this experiment four different organic fertilizers. plant material base organic fertilizer (POF), swine manure compost (SMC), poultry manure compost (PMC) and cow manure compost (CMC), were applied to the soil where Water Convolvulus and Pak-Choi were cultivated. The residual effects of these fertilizers to soil properties, the effects on the production of these two vegetables, and the nutrient absorption of the plants were investigated. The organic fertilizers were applied at the 2 and 4 times rates of the recommended conventional nitrogen application. Furthermore, two kinds of check were set: one full rate of chemical fertilizer (CF) and one no fertilizer treatment (CK). Totally ten treatments were included in this study and each with four replications. The field layout followed a randomized complete block design. For the first crop of Water Convolvulus and Pak-Choi, eight kilograms of soil is mixed with organic fertilizer each is equivalent to 2 and 4 times rate of 0.8589g N per pot. For the second crop, the same soil without applying organic fertilizer was used to study the residual effects. However, chemical compound fertilizer was applied the same rate as the first crop. The vegetables were sampled when they reached marketable size. Plants were analyzed, after being dried by 70 ℃ and ground, for the concentrations of elements such as Nitrogen, Phosphorus, Potassium, Calcium, and Magnesium. In addition, the soil was analyzed after the first harvest of Water Convolvulus and the second harvest of Pak-Choi. The analyzed items included pH, EC, the organic contents, inorganic nitrogen, Olsen phosphorus, exchangeable potassium, calcium, and magnesium. The results indicated that the addition of organic fertilizer soils increased pH value and electric conductivity (EC) of the soils. There were significantly different among the two rates of four organic fertilizers. There were significant differences on the production of the leafy vegetables for various fertilizer treatments in the two crops. The production of Water Convolvulus for PMC 4R and CMC 4R treatments were higher than chemical fertilizer. The production of plants for 4 R treatments was higher than that of 2 R treatments in manure compost. In the first crop of Pak-Choi : the relative production for organic fertilizer were higher than the chemical treatment except for POF and SMC 2R treatments. And, the production for two times organic fertilizer treatments were higher than four times treatments. Water Convolvulus had higher production than Pak-Choi at same growth period. The nutrients needs were different between Water Convolvulus and Pak-Choi, the former higher than the latter. The yields of Water Convolvulus and Pak-Choi for PMC 4R were all higher than that of CF. The production of Pak-Choi in the second crop was the residual effect of the first one. The production of POF was significantly higher than other treatments. The production of the two vegetables were low because of the lower rate of mineralization of nitrogen for SMC 2R. For the second crop, the production of Pak-Choi with two times of recommended nitrogen fertilizer were higher than that of chemical fertilizer treatment, yet no significant difference to four-times treatment. The pH and EC of soil increased after adding fertilizer. The most significant effect in promoting pH of soil, and EC was PMC 4R treatment. However, the soil EC dropped after second harvest of Pak-Choi, especially for the chemical fertilizer treatment. Water Convolvulus had higher adaptability on the soil pH than Pak-Choi. The POF 4R treatment had the highest inorganic N and nitrate nitrogen contents. Olsen phosphorus, exchangeable potassium and magnesium contents of soil for PMC 4R were significantly higher than other treatments. The application of the organic fertilizer significantly increased phosphorus content of soil. Nutrient absorption of plants significantly reflected on the production of plants. Positive correlations between the production and the absorptions of nitrogen, phosphorus, potassium, calcium and magnesium were observed. The correlations were more significant in the second harvest. The best absorption efficiency of fertilizers in first crop was as follows: nitrogen for CF, potassium for SMC 2R, calcium for CMC 2R, phosphorus for CMC 4R and 2R in convolvulus and Pak-Choi respectively. As for the second crop, nitrogen and potassium for CF, phosphorus, calcium and magnesium for POF 2R had the significantly higher absorption. Better production of Pak-Choi was observed by applying 300kg ha-1 nitrogen fertilizer. The residual effect of organic fertilizer applications showed higher nitrogen content and faster decomposition of minerals. The organic fertilizers should be applied two weeks before planting to avoid deleterious effect. It is enough to grow Pak-Choi by applying organic fertilizer with high-content nitrogen and be easily be decomposed when equivalent to recommend rate of chemical fertilizer. Positive correlation was observed between soil EC after the first crop harvested and the production of the second crop Pak-Choi. Checking soil EC before planting can serve as a guide of diagnose of soil fertility for rational fertilization.