Growth and Nitrogen Composition of Cabbage under High Application Rate of Hog Dung Compost

To compensate the slow nutrient release characteristic of soil organic matter, a high application rate of organic matter to establish the organic matter concentration of the soil is a common practice in organic farming. In this study, high rates of hog dung compost were applied to measure their effects on the growth, nitrogen (N), phosphorus (P), and potassium (K) uptake, and N composition of different parts of cabbages in field. Treatments consist of a conventional chemical fertilizer control plot and three rates (30, 60, and 120 Mg/ha) of hog dung compost-treated plots. The cabbage was harvested 94 days after transplanting. The dry weight and the concentrations of the total N, P, K, nitrate N (NO3(superscript -)-N), ammonium N (NH4(superscript +)-N) and insoluble N in various parts of the plants were determined. The results showed that there were no significant differences in growth and uptake of N and K for the various treatments. However, the P uptake of the cabbage received compost treatment was significantly higher than that received chemical fertilizer treatment. The NO3(superscript -)-N concentration in the whole plant of the chemical fertilizer-treated plants was the lowest among all treatments. However, there were no significant differences in the NO3(superscript -)-N concentrations of the head among the compost-treated plots. The total N and K concentrations of various parts of the plants were not significantly different among the treatments. However, the P concentrations in the chemical fertilizer-treated plants were lower and that in compost-treated plants increased as the compost rate increased. More than half of the total N in the head was in the form of soluble organic N. In conclusion, the yield at application rate of 30 Mg/ha of compost was equivalent to that of the conventional chemical fertilizer treatment and higher application rate of compost was not necessary for the first time of organic cultivation of cabbage. However, there is no disadvantageous effect on the growth of cabbage even at a single level of 120 Mg/ha of compost.