The Comprehensive Benefits Study Of Straw Covering On Chestnut Orchard In Mountain Region

The experiment about the straw covering on the soil in the representative chestnut orchard was done during nine years in Xinyang Mountain Region of Henan Province. Such indexes as soil moisture, soil temperature, soil fertility, nutrient level of chestnut trees, chestnut yield, chestnut quality, economic benefit were measured. The results showed that as followed.1.Straw covering could significantly increase the soil moisture content in chestnut orchard. Especially on the droughty mountainous orchard or in the weather of high air temperature and little rainwater, the effect of straw covering was more significantly. The soil moisture content of control orchard was up to the wilting moisture content of chestnut (10.3%). But the moisture content of treatment A(covering 20cm) was 34.7%. The difference between treatment A and the control was significant.2.Straw covering could evidently adjust the temperature in the top layer of the soil. In June and August, the high temperature in the top layer could nearly burn the chestnut roots to die. Straw covering could lower the top soil temperature, and as a result, reduce the risk of roots death of chestnut. In September and October, straw covering could delay the soil temperature decreasing. A higher soil temperature could promote the root growth, root absorbability, synthesizing and accumulating nutrient substance.3.Straw covering could increase soil fertility. After covering straw on mountainous chestnut orchard during the years, such content of organic matter in top soil, whole nitrogen, whole phosphorus, whole potassium, hydrolyzed nitrogen, available phosphorus, available potassium were increased in different degree. The physical character of soil was also improved after covering straw. The soil bulk density was reduced. Field moisture capacity and porosity percentage were increased. The ratio of solid, liquid, air composition in soil was rational, so the number of soil bacterium and azotobacter were significantly increased.4.Straw covering could increase the nutrient level of chestnut trees and growth and development. The ecological environment of soil was improved, so the whole root quantity was increased and the root distribution was enlarged. The root to crown ratio was increased. Those could promote the growth and development of chestnut trees. Such indexes of treatment chestnut trees as single leaf area, fresh leaf weight, chlorophyll, and the content of nitrogen, phosphorus, kalium were increased in different degree.5.Straw covering could increase the yield and quality of chestnut. The yield of treatment was higher than the control's. During the year of 1998 and 2001, the increased yield of average annual was up to 40.5%, 67.6%, 75.7%. And straw covering could reduce the happening of major or minor year of chestnut.Therefore, straw covering could significantly increase the economic benefit of orchard farmer. Straw covering had better ecological and social benefit.