Effect Of Conservation Tillage Measures On Crop Yield And Soil Fertility

This research is based on conservation tillage experiments in one crop a year area and two crops a year area. Study effects of different mulch,tillage methods on crop yields and soil fertility. Try to find scientific basis which can promote applications of conservation tillage in different areas. The results were as follow:1. Effects of conservation tillage on spring maize yield and soil feitility in one crop a year area(1)Different mulching methods can significantly increase spring maize yield, compared with no mulching treatment, the yield of straw mulching,plastic mulching and straw plastic mulching increased 5.7%,20.2%,23.8% respectively. No tillage method can not significantly increase crop yield, compared with tillage method, it only increased 2.0%. Different mulching methods can improve soil water and heat condition, effectively stop loss of water and increase WUE. The result shows WUE of straw plastic mulching increased 6.0 kg/(hm².mm) compared with no mulching. WUE of no tillage method increased only 0.7kg/(hm².mm) compared with tillage method.(2)The result of postpone harvest time experiment shows: 5 days after traditional harvest time, the spring maize yield increased 4.2%. The effect of yield promotion turns to be best at 15 days. After 30 days delay of harvest time, straw mulching method increased 2.2%. No mulching increased 2.5%. Straw and plastic mulching increased the lowest, which is only 1.3%. The yield of tillage method and no tillage method increased 2.0% and 1.8% respectively.(3)Absorption of N,P,K by spring maize increased the most under straw plastic mulching. Absorption of total N under no mulching is averagely 71.1kg/ hm². Compared with no mulching, the absorption of total N under straw mulching,plastic mulching and straw plastic mulching increased 26.41%,40.48%,51.23%. Absorption of total P,K tends to be the same trends under different mulching method. There is no significant difference between tillage and no tillage by absorption of total N,P,K.(4)Pn of spring maize under straw plastic mulching is the largest during the whole growth period. Compared with no mulching method, Pn of straw mulching,plastic mulching and straw plastic mulching increased 1.38,2.63,3.54μmol(/m²?s)。Pn under different tillage method has no significant difference. (5) Compactiveness of surface soil is used to evaluate tillage method. Compactiveness of 0-45cm soil under no mulching is averagely 1559Kp/cm²,compared with no mulching, straw mulching and straw plastic mulching declined 7.9%,10.3% respectively. There is no significant difference between plastic mulching and no mulching. Compactiveness of no tillage declined 1.1% compared with tillage.(6) Straw mulching increased O.M,Total N,Available P of soil ; plastic mulching reduced soil Available P. Compared with tillage method, no tillage method increased soil Total N,Total P,Available N,Available K, but O.M,Available P reduced 0.18g/kg and 0.16g/kg.2. Effects of mechanized conservation tillage on soil fertility in two crops a year area(1)Pn of wheat under mechanized conservation tillage has significant difference during heading and flowering period. Pn of SRs PRs and Ns has no significant difference, they increased 0.97μmol/(m²?s)compared with CT. AS increased 0.48μmol/(m²?s), but Rb and Nb is lower than CT.(2) Soil respiration rate of Nb is the lowest during the whole growth period, its highest level is 4.52μmol·m^-2·s^-1,and its lowest level is 1.79μmol·m^-2·s^-1. Soil respiration rate of Ns rises significantly during growth period. Soil respiration rate of TRs rises fast after jointing.(3) Compactiveness of 0-45cm soil under mechanized conservation tillage has large difference. Compactiveness of CT is 1939 Kp/cm², Compactiveness of RT is 1950 Kp/cm², which increased 0.59% compared with CT. Compactiveness of Sb,Ss,NT declined compared with CT.(4) Soil nutrient content increased in different level under mechanized conservation tillage. Soil nutrient of RT increased the highest, compared with CT, its O.M,Total N and Available K increased 20%,17%,38%. Ss contributes to P content, its Total P and Available P increased 27% and 69% compared with CT.