Nutrient release rate of tung oil-coated urea and its influence on ryegrass growth

Basic features and coating layer morphology of 4 kinds of the oil of tung tree(Aleurites fordii)coated urea (TCU) were characterized, the nutrient released curve and nutrient released rate of TCU were also determined . Soil culture experiment was used to study the influence on growth, morphological index, and the color of ryegrass (Lolium perenne) with base fertilizer of urea and TCU at two levels of N fertilizer rate of 0 and 15.8 g/m2. The results showed that all the basal dressing treatment had contributed the emerging of the ryegrass, after sowing 4-5 weeks, the plant height and biomass of ryegrass for TCU and urea treatment were superior to those of none-fertilizer treatment, however, the difference between TCU treatment and urea treatment was not remarkable. After sowing 5-6 weeks, the plant height and biomass of ryegrass for TCU treatment of UT-02 and UC-04(both with longer nutrient released period, theirs t80 reached 24d and 26d, respectively)were exceeded those of ryegrass for urea treatment, and the green periods was longer than 7 weeks for those TCU treatment, which was superior that of 5 weeks for urea treatment.