| As the fastest-growing trees among fast growing tree species in China’s southern plantations, eucalyptuses have drawn universal concerns of the whole society. Being a symbolic and representative fast-growing tree species in China’s southern plantations, eucalyptuses planted in Guangxi rank top in terms of total number. In order to investigate the effect of different special fertilizers on E.urophylla×E.grandis saplings, three pilot sites were set up at the beginning of2011in Dongshan and Hesong branch of Guangxi Yulin state-owned Liuwan forest as well as Nama town in Liangqing District of Nanning. Sulfuric acid granulated fertilizer, steam granulated fertilizer, coated fertilizer, and eucalyptus active fertilizer produced by Guangxi Chemical Industry Research Institute were compared with special compound fertilizer produced by state-owned One forest itself in terms of topdressing effect. Newly planted eucalyptuses belong to test area in Dongshan branch, whereas E.urophylla×E.grandis saplings were planted in test area in Hesong branch. Each test area was treated with five different fertilizers:fertilizer A (sulfuric acid granulated fertilizer500g per plant), fertilizer B (steam granulated fertilizer500g per plant), fertilizer C (coated fertilizer500g per plant), fertilizer D (special compound fertilizer produced by state-owned One forest475g per plant+eucalyptus active fertilizer25g per plant) and fertilizer E (special compound fertilizer produced by state-owned One forest500g per plant). E.urophylla×E.grandis saplings were planted in the test area of Nanning Huiwanger Agrochemicals Co., Ltd. which is located in Nama town in Liangqing District of Nanning. Three treatments were applied using steam granulated fertilizer in Huiwanger company’s test area, namely B1(500g per plant), B2(750g per plant) and B3(1000g per plant) respectively. Through measurements and analyses of height, DBH, volume, biomass, nutrient elements accumulation of E.urophyllaxE.grandis tree, key findings are listed with the stand age of1.6a as follows:(1) The effect of various topdressings on E.urophylla×E.grandis growth indicators:①the impact on tree height:in the test area in Dongshan branch of Guangxi state-owned Liuwan forest, it was8.40m,9.98m,8.67m,9.11m and8.25m after treatment A, B, C, D, and E respectively; in the test area in Hesong branch of Guangxi state-owned Liuwan forest, it was9.16m,9.20m,10.36m,9.52m and8.51m after treatment A, B, C, D, and E respectively; in the test area of Nanning Huiwanger Agrochemicals Co., Ltd, it was9.68m,10.58m and9.54m after treatment B1, B2, B3respectively.②the impact on DBH:in the test area in Dongshan branch of Guangxi state-owned Liuwan forest, the DBH of E.urophyllaxE.grandis averaged8.15cm,9.40cm,7.68cm,8.50cm and7.51cm after treatment A, B, C, D, and E respectively; in the test area in Hesong branch of Guangxi state-owned Liuwan forest, the DBH of E.urophyllaxE.grandis averaged8.18cm,8.29cm,8.66cm,8.53cm and7.99cm after treatment A, B, C, D, and E respectively; in the test area of Nanning Huiwanger Agrochemicals Co., Ltd, the DBH of E.urophyllaxE.grandis averaged8.26cm,9.57cm and8.17cm after treatment B1, B2, B3respectively.③the impact on individual volume:in the test area in Dongshan branch of Guangxi state-owned Liuwan forest, E.urophylla×E.grandis individual volume averaged24.085×10-3m3per plant,36.581×10-3m3per plant,22.489×10-3m3per plant,28.173×10-3m3per plant and20.735×10-3m3per plant after treatment A, B, C, D, and E respectively; in the test area in Hesong branch of Guangxi state-owned Liuwan forest, E.urophylla×E.grandis individual volume averaged26.448x10-3m3per plant,27.086×10-3m3per plant,32.499×10-3m3per plant,29.403×10-3m3per plant and23.767×10-3m3per plant after treatment A, B, C, D, and E respectively; in the test area of Nanning Huiwanger Agrochemicals Co., Ltd(Nama town in Liangqing District of Nanning), E.urophyllaxE.grandis individual volume averaged28.149×10-3m3per plant,39.700×10-3m3per plant and27.231×10-3m3per plant after treatment B1, B2, B3respectively.(2) The effect of various topdressings on E.urophyllaxE.grandis biomass in the test area in Dongshan branch of Guangxi state-owned Liuwan forest:the E.urophylla×E.grandis total biomass accumulation after treatment A, B, C, D, and E respectively was37.285t/hm2,39.983t/hm2,34.934t/hm2,39.343t/hm2and33.669t/hm2. Of E.urophylla×E.grandis total biomass, trunk biomass accumulation occupies the largest proportion, which made up41.07%(9.196kg per plant),41.24%(9.893kg per plant),42.27%(8.868kg per plant),40.47%(9.562kg per plant) and42.97%(8.688kg per plant).(3) The effect of various topdressings on E.urophyllaxE.grandis nutrition in the test area in Dongshan branch of Guangxi state-owned Liuwan forest:when the stand age was1.6a, treatment B ranked highest among annual average accumulation of nutritional elements such as N, P and K in E.urophylla×E.grandis stands after various treatments. Accumulation rate of nitrogen, phosphorus and potassium was the fastest in E.urophylla×E.grandis leaves, followed by bark, branches, roots and trunks. |
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