| This research was conducted in the field in Shandong Agricultural University in 2014-2015, which was to explore the changes of nutrition in soil and the response of crops to different tillage methods. Two crop species, wheat and maize, were planted every year in this farming system. Some parameters including physical and chemical characters, microbial properties, and enzyme activities, Soil respiration and contributions of its components and crop yield were examined at different season of each year, and the effects of different tillage methods on these parameters were analyzed. These results can give some suggestions for the application of different tillage patterns in the system of high efficiency and low expending agriculture.The major results were as follows: 1 Soil physical-chemical propertiesSoil temperature reaches a minimum value during the winter, At this time conservation tillage than PC. When it's growing late, conservation tillage than PC. Conservation tillage effect of keep on water, moisture PZ and PS than other tillage methods.PZ and PS significantly increased organic carbon, total nitrogen, available phosphorus, available potassium in 0-20 cm soil layer. PH?PR in 0- 10 cm soil layer of each nutrient content, 10-30 cm soil content is close to the minimum content of 30-40 cm; Each index and PC was distributed uniformly in 0-40 cm soil layer. Long-term conservation tillage can cause the soil surface enrichment and the lower poor. 2 Soil biological propertiesCompared with PC, conservation tillage soil microbial quantity 0-10 cm soil layer was higher than in 10-20 cm, 0-20 cm soil layer conservation was lower than PC. 0-20 cm soil layer PC soil microbial quantity was higher. PZ and PS was helpful to improve in 0-10 cm soil microbial quantity.Conservation tillage Enzyme activity in 0-10 cm soil layer was higher than PC. Urease activity PS was highest, then PC and PR was lowest. Sucrase activity PC in 0-10 cm soil layer was highest, then PZ was lowest. Catalase activity PZ was highest. 3 Soil respiration propertiesThe effect of tillage methods on soil respiration was significant. Wheat and maize soil respiration showed the same trend. Maize soil respiration was higher than wheat respiration, with the mean value of 3.2. Conservation tillage was lower than PC. which PZ compared with PC decreased by 37.0%; PS Compared with PZ, increased by 25.9%, root respiration PS is the highest; contribution of root respiration tillage wheat season-average performance for the highest average contribution of each treatment was 49.3%, Maize season showed deep pine highest average each treatment contribution rate of 50.7%, no significant difference between where PS, PC with harrow was no significant difference. PS can improve to root growth, promote root respiration, improve crop nutrient absorption capacity, can lay a good foundation for crop yields. 4 Crop yield and component factorsCompared with PC, PZ reduced the grain number per ear of Maize, number of productive ear and 1000-grain weight of wheat, while PS increased the yield of maize and PZ increased the yield of wheat. From analyzing straw stubble returning, PS yield was the best, Wheat yield can improve of 12.3%, Maize yield of 18.6%. 5 Soil respiration and soil quality, soil quality and crop yield were significantly correlated.The soil respiration was significantly positively correlated with soil temperature, soil moisture and soil organic carbon, while negative correlated with soil total nitrogen and available potassium. The soil temperature was the most important factor which affected soil respiration. The soil respiration was significantly positively correlated with soil quantity of microorganisms, enzyme activities.The soil temperature was significantly positively correlated with the content of soil moisture,organic carbon, microorganism quantity(except bacteria), enzyme activity and grain yield. These results suggested that tillage and straw returning can increase grain yield by improving microorganism quantity and enzyme activities and soil nutrients.Considering all factors, PS tillage is the favorable agricultural tillage method in this regio n to improve soil physical and chemical properties, biological traits, at simultaneously reduce the greenhouse gas emissions and increase crop yields. |
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