Effects Of Slow-release Nitrogen Fertilizer Application Rates On Growth, Physiology, And Fertilizer Utilization Of Eggplant

In pursuit of higher yield, superfluous fertilizer are used in agricultural production that not only increases cost, decreases the quality of productions, but also contaminates the environment. Reasonable use and efficiency promotion of nitrogenous fertilizer are essential paths of sustainable agriculture. Controlled-release fertilizer which has long sustained-release time and higher absorption efficiency is a new kind of fertilizer which could validly improve production equality, and decrease the cost of products and environmental pollution. Took ‘Longyouchangqie’ as test material, designed non-fertilizer as CK, T1 384 kg·hm-2, T2 288 kg·hm-2, T3 231 kg·hm-2 and T4 192 kg·hm-2 were the treatments, the pot-experiment was conducted to study the effects of controlled-release fertilizer on growth physiology, yield and quality of fruits, nutrient amount arrangement and enzyme activity change in the substrate, to provide a reliable amount of controlled-release fertilizer in organic substrate cultivation of solanaceous vegetables. The main results were as follow:1. Plant height, stem diameter and dry mass accumulation of 4 fertilization treatments significantly improved compared with CK. The height(102.1cm) and stem diameter(13.88mm) of T1 were the greatest; the dry matter of T3(12145 kg·hm-2) was the greatest. The dry matter accumulation of each organ showed fruit>leaf>stem>root.2. Compared with CK, the contents of chlorophyll a, chlorophyll b and carotenoid in eggplant leaves of 4 fertilization treatments were significantly increased after anthesis, T1 maintained the highest for a long period. Pn, Gs, Tr, Fv/Fm, ΦPSⅡ and qP increased during early growth stage, but the growth rate decreased with the increase of nitrogen fertilizing amount, after entering the anthesis period, 4 fertilization treatments were significantly greater than CK, and in a long period, T3 maintained the maximum; Ci, NPQ increased in the fruiting period, and CK was higher than that of treatments.3. Fertilization treatments significantly improved the yield and single weight of eggplant. Yield of T3(61920kg·hm-2) was the highest and improved by 169.52% than the CK. There was a significant correlation between fertilizer amount(x) and yield(y): y=-0.5709x2+290.03x+22915, R2=0.9899**.4. Nitrate in fruit of each treatment was significantly higher than CK, increased by 26.73%-91.31%; soluble sugar(3.433%) and soluble protein(2.264mg·kg-1) of T3, Vc of T4(70.610mg·100g-1) were the highest of all treatments.5. Efficiency of nitrogen fertilizer decreased with increase of fertilizing amount, and T4(36.78%) was the highest, efficiency of phosphatic fertilizer(23.23%) and potash fertilizer(33.82%) of T3 were the highest. Distribution amount of N, P, K in each organ showed that fruit>leaf>stem>root.6. Fertilizer significantly increased the amount of total nitrogen, alkaline hydrolysis nitrogen, ammonium nitrogen and nitrate nitrogen in the substrate, and they positive correlated with fertilizing amount. The Urease and Invertase activity increased with the increase of the amount of nitrogen fertilizer, and the treatments were significantly higher than those of CK, Catalase activity in CK was 6.190mL·g-1·h-1 and the highest, which was significantly higher than that in each of the treatments.