Study On Effects Of No-tillage And Straw Return On Microbe Amount, Enzyme Activity In Soil And The Growth Of Ligusticum Chuanxiong

With the Chuanxiong seed of Shenxiandong town of Dujiangyan County of Sichuan as the material, a field experiment in Mazu Country of Dujiangyan were conducted to study the effect of no-tillage and straw return on microbe amount, enzyme activity, fertility in soil, growth, dry mass allocation, yield and quality of Chuanxiong. The results were as follows:1. The amount of soil microorganism was increased significantly by no-tillage in the second stem and leave growth period and rhizome expanding period. The amount of bacterium and actinomycete in soil had little difference between tillage and no-tillage at the harvest period, but the amount of fungus was lower than no-tillage. The amount of bacterium and actinomycete in soil was increased significantly by straw return, and as the overlay capacity of straw increased, the amount of soil microorganism was raised, and the effect of chopped cover was better than covered with the whole plant, so the amount of soil microorganism with the whole plant(500kg/667m2) and chopped (250kg/667m2) straw covered was higher in this experimental conditions.2. The activity of cellulase, protease, urease in soil were increased by no-tillage and straw return, but there was no influence on catalase. The soil enzyme activity under the straw cover treatments was higher than CK, and as the overlay capacity of straw increased, the activity of soil enzyme was raised, and the effect of chopped cover was better than covered with the whole plant, especially at the late growth stage. In the three determination periods, urease activity treated by the whole straw double amount was the highest, and prolease treated by the middle amount straw chopped covered was the highest. In the second stem and leave growth period and rhizome expanding period, the activity of soil catalase and cellulase treated by the whole straw double amount was the highest, but at the harvesttime, the enzymatic activity treated by the middle amount straw chopped covered was the highest.3. The contents of soil organic matter, alkali-hydrolyzable nitrogen, available phosphorus and efficiency potassium were accelerated significantly by the whole straw (500kg/667m2) and chopped straw (250kg/667m2), and there was no significant difference between no-tillage and tillage.4. The whole straw covered had some effect on seeding emergence of Chuanxiong, but chopped straw covered could increase the seeding rate. The growth of root, stem, leaf and the plant height was promoted by tillage at the early grow period, but this effect was reduced as the growth process progress gradually, and the tuber formation and enlargement was promoted by no-tillage. Straw covered played a promoted role in the growth of Chuanxiong, especially chopped covered, and the weight of each organ showed as the middle amount straw chopped covered(E) > the middle amount (C) and the double amount (D) straw whole covered> the half amount(B) straw whole covered> CK(A).5. The economic benefit of Chuanxiong was raised significantly by no-tillage. But no-tillage had a certain influence on the content of the ferulic acid, total alkaloid and other quality indicators.the yield,quality and economic efficiency of Chuanxiong were improved significantly by straw mulching cultivation, and the effect of middle amount straw chopped covered was the best. In the whole straw covered treatment, the yield and quality of Chuanxiong by the double and the middle amount were better than half the amount of covering. The production/investment by the half the amount was lower than the middle amount of covering, and the double amount was the lowest.6. Statistical analysis showed that amount of bacteria, actinomycetes and the activity of urease, catalase, cellulase, protease in soil had positive correlation with soil nitrogen, phosphorus, potassium and organic matter content. The yield of Chuanxiong had positive correlation with some soil enzyme, soil fertility characteristics, plant height and stem number, it indicated that the mechanism of mulching straw was increasing the amount of soil bacteria, actinomycetes, the activity of soil enzyme, promoting the decomposition of organic matter, improving soil fertility, thus the plant growth was promoted and the yield and quality of Chuanxiong were improved.