Effect of different composts on growth and nitrogen composition of Chinesemustard in an acid red soil

A pot experiment was conducted to assess the effect of different kinds of c omposts on the growth and nitrogen (N) composition of Chinese mustard in ac id red soil. There were six treatments including a lime-chemical fertilizer treatment and a control plot of conventional chemical fertilizer. The plan ts were harvested 37 days after transplanting and the growth and N composit ion of these plants were measured. The soil was also sampled, and selected chemical properties were determined after harvesting the plants. The result s show that different composts affected the growth and soil chemical proper ties significantly. The pH, nitrate nitrogen (NO3-N), ammonium N (NH4-N), e lectrical conductivity (EC), and 1 N ammonium acetate exchangeable potassiu m (K), calcium (Ca), magnesium (Mg), aluminum (Al), manganese (Mn), and iro n (Fe) were all significantly affected by the compost treatment. The growth of plants in the control treatment was significantly lower than that of th e compost-treated and lime-treated plants, suggesting that the acid Oxisol is unfavorable for the growth of Chinese mustard. Some composts could incre ase the growth of Chinese mustard. The lime-treated plants had higher conce ntrations of chlorophyll a and chlorophyll b than those of the compost-trea ted plants. There were no significant differences between treatments in the concentrations of chlorophyll. a and chlorophyll b, however, there was a c lose correlation between the total chlorophyll concentrations and the shoot yield of the plants. The NO3-N, soluble reduced N, and insoluble N concent rations in leaf blades and petioles of Chinese mustard varied significantly according to the compost applied. The hog dung compost B could adequately supply nutrients especially N for plant growth and caused little NO3-N accu mulation in plant tissues.