Study On The Tree-structure Indexes With A Saving-labor And High-effficent System In Pear Orchard

In this paper, pear trees of different years (7and8years), cultivation densities(high-density, medium-density planting, and low-density), and different cultivated varieties(Xueqing and Hongxiangsu) were used for the studies of the indexes of tree structure,canopy characteristics, and light distribution conditions. The main results were as follows:1. The indexes of tree structure such as trunk height, trunk diameter, tree height,branches spread from east to west and shoots even types of branches in saving-labor andhigh-effficent production, were studied. The result indicates that selection of tree form, andits corresponding indexes of tree structure was the precondition of fruit fertility, becausepear trees with appropriate planting density and tree structure can make full use of soil andspace and give full play to the potential of fruit production. The tree-structure indexes offull bearing trees were studied with a pillar system in a saving-labor and high-effficent pearorchard. The results showed that the appropriate trunk height was55-60cm with a treeheight of300cm. Around the central leader18-22large and medium bearing shoot groupswere distributed, forming a hedgerow in a line. For a single tree,127.2-160.2various typesof shoots remained, converting to5.300×105-6.675×105ones per hectare. The percentageof spurs was about69.7%-76.0%with a ratio of growing to bearing woods being1:1.48-1:1.57. Averagely,70-80fruits were left per tree and the output ranged from86t/hm2to100t/hm2. The fruit SSC was above12%. In conclusion, there were manyadvantages with respect to the pillar system, such as stable tree vigor, good light reception,higher land availability and output, simple management and convinience for mechanicaloperation, etc.2. The result of biological characteristics of crown and light characteristics analysis indifferent planting densities showed that under the planting density with0.75m×3.2m ofXueqing, the leaf number was555.8-708.2per square meter and the ground coverage wasbelow60%with a leaf area index of3.6-4.6. The light intensity from9am to11am was10000lx under the crown, while relative light intensity was below30%, the same time, thelight intensity was20000lx on the crown while relative light intensity was above30%.The total radiation was less than1000mol·m-2·yr-1at low-density that was8years old. In conclusion, there were good light reception.3. The content of N, P, K, Ca, Mg, Fe, Mn, and B in pear leaves of Xueqing undersaving-labor and high-effficent production was analyzed. The result showed that contentsof each mineral element were different in pear leaves of Xueqing in the orchards ofdifferent planting densities. The content of N and Mn were highest in dwarfing andsaving-labor pear orchard and there is no significant difference between other mineralelements.4. Controlling the light conditions is the key technology for maintaining the fruitshigh quality and high yield of the pear trees in saving-labor and high-effficent pearorchards. The central part of hedgerow, of pear trees in dwarfing and closely spacedplanting orchard has started to light conditions adverse trends, so to prevent thedeterioration of light conditions, the crown and tree height should be controlled strictly.