Techniques On High Standard Farmland Forest Network

High standard farmland forest network is concerned by the scientists and governors. Because it can resolve the problems existed in current farm protective forest belt, and provide better ecological benefits, economic benefits and social benefits. This paper takes the farmland shelter forest as a case, which focuses on its key technique, and aims at theoretical basis for construction. The study was comprised of three parts:â‘ the key techniques of farmland shelter forest optimal schemes.â‘¡the assessment on the benefit of high standard farmland shelter forest, together with its feasibility.â‘¢a integral technique system was proposed based on the above research. The main results are as follows:1. Key techniquesThe proper tree species used in shelter forest are selected based on ecological adaptation, protected capability, economy benefit. Poplar Zhonglin-46, Poplar I-107, Paulownia C125 are prior to those species including Robinia pseudoacacia, Salix matsudana Koidz, Chosenia arbutifolia, Ailanthus altissima, Melia azedarach, Fraxinus bungeana, Ulmus pumila. Economic tree species included Ziziphus jujube Mill., Diospyros kakiL.f.,Crataegus pinnpatifida Bunge. Understorey species include Amorpha fruticosa, Platycladus orientalis, grazing(clover blossom).The best space of main forest is 250m-300m, the secondary one is 500m-600m. The grid size is 180-300 mu. Generally, the forest belt interplant spacing is 3m×4m and 2-4 line. The suitable porosity is 0.30-0.45. The frutex planted under the forest belt can form perfect porosity structure. So, we can increase the mixed proportion of arbor and shrub to meet with different kinds of protective aim.Fertilization was carried out for Poplar I-107, Poplar Zhonglin-46 and Ulmus pumila. The results indicated that the best ratio of Poplar I-107 is N:P₂O₅:K₂O=1:0.5:1. That of Poplar Zhonglin-46 is N:P₂O₅:K₂O=1:0.5:0.5. That of Ulmus pumila is N:P₂O₅:K₂O=0.5:0.5:1.The harder pruning intensity is, the lower tree growth is. When pruning intensity exceedes 30%, the reduced growth range increases. One year to five year forest had better mild pruning or pruning competitive branch.When pruning practice is carried to those new shelter forest, the 30% pruning intensity is best in young stage. Excessive thinner pruning intensity does no benefit to improve lignum, while excessive thicker is not benefit to hurricane lamp efficiency, especially narrow forest belt. Half belt regeneration is the best regeneration mode, which has better protective function in forest growth and hurricane lamp efficiency.2. The ecological functions of high standard farmland forest are evaluated. The results show: Narrow belt, sparse structure or ventilation structure, and mixed forest can accelerate forest growth and increase shelter effects. It is a good type for high standard farmland shelter forest. Forest total increment can be advanced 25% compared to that of general forest network. Wheat, corn and cotton can be increased 6%, 4%, 2.8%.3. Based on the above research, a comprehensive technique is proposed, including tree species choice and collocation, afforestation, bursting and weed control, fertilization, pruning, thinning, regeneration and stand control.