Economic Benefits of Rubber Plantations in Longjiang Farm in Hainan by the Application of Optimized Fertilization Formula

The influence of formula fertilization optimization on dry rubber yield and economic benefits of the rubber plantation in Hainan Longjiang Farm were studied by using ＂contrast＂ design method of fertilizer field experiments. The results showed that the actual production rate reached 4.61% and the net production rate of dry rubber reached 3.97% by application of optimized fertilization formula. Analysis of variance showed that the average dry rubber yield in optimization of formula fertil- ization area was significantly higher than that of conventional area. The results also indicated that the optimization of formula fertilization had obvious economic benefits, and each rubber tree reduced cost and increased 9.95 yuan on average after the test.

Effects of Fertilization on Young Populus deltoids cv. Zhonghua Hongye Growth

Using complete and orthogonal design, fertilization trials were conducted for the young growth of Populus deltoids cv. Zhonghua hongye in the fluviogenic soil in Xindu District, Chengdu City. The results showed that the application ef- fect of the single nutrient elements ranked as K〉N〉P, and that of the fertilization combinations ranked as N＋P＋K〉N＋K〉N＋P, P＋K. The optimum fertilization formula was urea [（NH2）2CO, 150 g/plant] ＋ calcium superphosphate [Ca（H2PO4）2.H20, 220 g/plant] ＋ potassium sulphate （K2SO4, 75 g/plant）.

Preliminary Report on Application Effects of Slow-release Formula Fertilizer in Tea Plants

In order to accelerate the construction of green production mode for tea in Hubei Province, improve the yield of tea and use efficiency of fertilizers, and improve the quality of tea, application effects of special slow-release formula fertilizer in tea plants were investigated in Wuhan. The results showed that compared with conventional fertilization, application of tea plant-specific slow-release formula fertilizer improved the yield of tea by more than 30%. The amino acid content in tea was increased by 21.05% and 30.82%, respectively, and the income was increased 27 696 （33.88%） and 27 624 （33.79%） yuan/hm2, respectively.

Chinese yam yield is affected by soil nutrient levels and interactions among N, P, and K fertilizers

Objective: The current fertilization methods for Chinese yam are uneconomic and unfriend to environment. A rational one is very important to achieve desired balance of high yield of Chinese yam, economic and friend to environment. Here, we studied the effects of nitrogen(N), phosphorus(P), and potassium(K) fertilizers on the yield of ’Qinfeng’ Chinese yam in shallow-groove directional cultivation.Methods: The experiments were conducted in Dehua County, Fujian Province, China using a "3414" optimal design. Overall, three fertilizer factors(N, P, and K) were evaluated at the following four levels: 0, no fertilizer;1, 0.5-fold the typical rate;2, typical fertilization rate;and 3, 1.5-fold the typical rate. There were 14 different fertilization treatments.Results: Treatment 6(N2P2K2) produced the longest(75.6 cm) and thickest tubers(4.9 cm) with the highest tuber fresh weight(1311.9 g) and yield(41 015.9 kg/hm2), whereas, treatment 1 produced the shortest(65.6 cm) and thinnest tubers(3.9 cm) with the lowest fresh weight(953.4 g) and yield(28 532.8 kg/hm2) among the 14 fertilizer combinations. The experimental data could be fitted to single-variable quadratic and binary quadratic models but not to a ternary quadratic polynomial model. Appropriate N, P, and K fertilizer application rates increased Chinese yam yield. However, excessive fertilization lowered the yield. Chinese yam yield was significantly and strongly correlated with the amounts of N, P, and K fertilizer applied.Conclusion: Based on the single variable quadratic and binary quadratic models, we propose that the quantities of N, P, and K fertilizer used to grow 1 hm^(2)’Qinfeng’ Chinese yam should be 360–388.3,90–100.95, and 416.3–675 kg, respectively.