The Pathway And Technology Of Controlling Ecosystem Of An Apple Orchard In Changwu County

Loess plateau is one of the most suitable area for excellent-quality apples in China, which plays an important role in the country's apple supply. The apple industry has become one of the most developed and profitable industry in Shaanxi. However, with the expansion of this industry and the increase of plantation age, the soil ecosystem of this area results in desiccation, reduced capability in controlling orchard ecosystem. In addition, orchardists here pay over attention just to improve the yield, ignore keeping orchards'ecosystem health, thus yield of orchard can not be sustained. Nowadays, most of orchard researches attach importance of apple tree's growing, however, they have done little work on how to improve and sustain soil ecosystem in orchard.For this, this research employ double elements mulching, furrow- ridge mulching technologies to control soil moisture and soil temperature based on single element mulching to do further study on effects of mulching tech in orchard. In addition, effects of appropriate productivity on soil moisture environment and eco-profits was studied. The results show that:(1) Soil moisture situation changed with tree's condition and rainfall, there were three periods: stable soil moisture period, losing soil moisture period and increasing soil moisture period. Of he four kinds of single element mulching ways, film mulching and straw mulching had higher soil water storage, 153.99 mm and 150.33 mm respectively, 140.27 mm for gravel mulching, water retention decreased significantly compared to the past years. Of the two kinds of double elements mulching methods, film over straw mulching performed better than straw over film mulching.(2) In stable soil moisture period, the 0-260 cm soil profile soil moisture of film over straw mulching is 26.9%, which indicates this method can retain soil moisture to supply demands of apple tree's growth; in losing soil moisture period, the mean soil profile moisture content was 26.2%, which is significantly higher than other measures. In the increasing moisture period, film mulching pathway performed the best water retention ability among all kinds of single element mulching, soil water storage increased by 8.48 mm, increase rate was 7.15%; soil water storage of film mulching, growing grass and straw mulching are significantly higher. As long term gravel mulching treatment can form plough pan which can hinder soil water infiltration, the soil water storage after rainy season was merely 140.27 mm which was little higher than CK(139.82 mm). Film over straw mulching water storage was 157.27 mm , 12.60 mm higher than before rainy season, the supply rate of rainfall to soil moisture was 9.52%, which was significantly higher than the others.(3) In order to improve mulching treatment benefit , furrow-ridge combined with double elements mulching was applied, in the vertical direction, soil moisture condition of different positions from the ridge appeared as a increasing trend around the center of 60^-100 cm soil profile to up and down direction. In horizontal direction, soil moisture of different positions were almost the same in the profile of 0 to 200 cm, between 30.9 to 31.4%. under 220 cm depth, soil moisture of center ridge was significantly lower than the other two positions. In 0 to 600 cm profile, water storage of center ridge, junction and center furrow were 168.1mm, 167.1mm and 161.2mm , respectively. So, furrow-ridge combined with double element mulching appeared to be more effective than double element mulching.(4) Soil heat condition showed obvious variance of different managements in summer, mean daily temperature, film mulching was 31.9℃, which was over 30℃, and would surely damage apple tree route system, straw mulching, gravel mulching control temperature steady at 18.9-22.5℃. film over straw mulching and straw over film mulching also showed well controlling on soil temperature.(5) Different managements showed significant effects on tree vigor, film mulching had a most high short branch rate( 31.05%), which matches with film over straw mulching, 4.61% more than straw over film mulching. Yield of film over straw mulching was 12550kg/ha, which was the highest among all treatments. As under the condition of valsa canker, effects of different managements on disease resistance were significantly different from each other, reduction of film over straw mulching was the lowest, which was significantly lower than film mulching, straw mulching and gravel mulching, was extremely lower than CK and growing grass. The two kinds of double elements mulching showed obvious resistance to valsa canker.(6) Soil water content increased with the decrease of productivity, soil water content of 1.8×105 Ind.ha^-1,2.25×105 Ind.ha^-1,2.7×105 Ind.ha^-1,3.1×105Ind.ha^-1 was 12.48%,11.68%,9.55% higher than CK, respectively. Yield of lower productivity levels was 50.85 to 89.46% higher than CK. 2.25×105 Ind.ha^-1 productivity, increased yield by 97.4%, input-output rate was 1:4.5, the highest among all levels. (7) Total nitrogen, phosphorus and kronium of branch increased with decrease of productivity, the health condition and disease resistance improved. By researching effects of valsa canker on yield reduction, reduction rate reduced as the productivity decreased, 1.8×10⁵ Ind.ha^-1,1.5×10⁵ Ind.ha^-1 had a reduction under 8%. Above all, applying of appropriate productivity can prolong full period of orchard.(8) By comprehensive effects of mulching treatments on soil ecosystem and tree response to mulching, an overall merit was applied, the results of film over straw mulching, gravel mulching, straw over film mulching, film mulching, straw mulching, growing grass and clean plough was 0.763, 0.673, 0.540, 0.335, 0.288 and 0.099 , respectively, the comprehensive index of film over straw mulching was the highest, and then was gravel mulching, but gravel mulching could form plough pan, which hinder the daily managements of orchard, so film over straw mulching was the most appropriate pathway in controlling and managing ecosystem of orchard in loess plateau.By comparing yield and economical benefits of different productivity levels, the results showed that 2.25×10⁵Ind.ha^-1 appeared to be the most appropriate productivity for the studying area.