In recent years, the rapid development of eucalyptus plantations in the short-cutting period has greatly eased the contradiction between supply and demand for timber and forest products in China, and the planted area has exceeded 2 million square hm. At present, the mode of eucalyptus planting in China is dominated by pure forests. In some regions, attempts have also been made to establish models for mixed forests, intercropping with forest farmers, etc., on the one hand, to promote the growth of eucalyptus and improve economic efficiency. On the other hand, it is also exploring the maintenance of eucalyptus plantations. A reasonable model of long-term productivity. The level of forest productivity is always closely related to the soil. Changes in forest vegetation affect soil properties. The level of soil fertility is the key to the sustainable management of forest land. Studies have pointed out that the mixed forest of Eucalyptus urophylla and Acacia, and the afforestation of Eucalyptus forests can effectively increase soil nutrient content and increase soil fertility. The total soil fertility of Eucalyptus urophylla trees after continuous planting has a tendency to decrease. In order to further study the changes of soil nutrients under different planting conditions of eucalyptus plantations, the effects of different slopes, forest ages, algebras, mixed models, and previous cropping species on soil nutrients in eucalyptus plantations were studied in order to select and determine the eucalyptus plantation The planting conditions and sustainable management methods provide the theoretical basis. The planting factors in the test site include slope, forest age, algebraic number, mixed cropping pattern, and previous cropping tree species. Three 400 square meters standard plots were set in each sampling plot and tested with a soil tester. brass fittings according to EN1254,the material is DZR602 and 754S,brass fittings,brass plumbing fittings,brass pipe fittings,connex brass fittings,yorkshire brass fittings,pegler brass fittings brass fittings,brass plumbing fittings,brass pipe fittings,connex brass fittings,yorkshire brass fittings,pegler brass fittings Taizhou Runde Company , https://www.zjbrassfittings.com
The experimental sites were set up at Qipo Forest Farm, Qinlin Forest Farm and Daguishan Forest Farm in Guangxi respectively. Qipo Forest Farm is located in the southwest of Guangxi, with a subtropical monsoon climate. The annual average temperature is 21.6 °C and the annual average rainfall is 1 304.2 mm. The Qinlian Forest site is located in the south of Guangxi and belongs to the subtropical monsoon oceanic climate. The average annual temperature is 22 .9 °C, with an average annual rainfall of 1 670 mm. The Daguishan Forest site is located in the northeast of Guangxi, north of the Tropic of Cancer, in the transition zone between the subtropical and southern subtropical zones. It is a subtropical monsoon climate with an annual average temperature of 19.9 °C. The average rainfall is 1 547 mm. The surveyed soil was red soil.