| Bashang area is located in North China Agriculture-Pasturage Interlaced Zone, it has a cold and dry weather, the difference of the temperature between day and night is high, soil fertility low and wind erosion is acute in there. The growing season of crop is short and low yield. Face to the all of above, in 2013-2014 in Zhangbei, Hebei Agricultural University Experiment Station, Cold and Arid Regions North relying locate 11-year no-tillage, subsoiling, plowing field trial basis, through the auxiliary setting conventional tillage after 10-year no tillage and subsoiling, the soil microbial carbon(C), active microbe amount, and soil respiration rate in the field planted naked oats were monitored to determine the effects of tillage method on microbe actions and depth analysis the relation mechanism of them; dominant weed species, weed diversity and the effects of weed biomass and oat yield; Catcher Yan soil moisture hardness and density changes, and the effect of oat yield under different tillage. To reveal the influence characteristics of tillage methods to soil microorganism,provide the theoretical basis for the application and creation of farming techniques for rising the resource productivity of water. The main findings are as follows :1. The result of 2013 and 2014 show that no-tillage soil microbial C in 0-10 cm was higher than 10-20 cm, soil microbial C in subsoiling and conventional tillage were almost the same in 0-10 cm and 10-20 cm,which in plowing after no tillage and sub soiling close to conventional tillage. Soil microbial C in 0-10 cm and 10-20 cm soil layer of chestnut soil were 2.53 mg/100 g and 2.62mg/100 g, lowest in heading stage; 44.54 mg/100 g and 19.40 mg/100 g in the maturity stage which were the highest in 2013. Soil microbial C in 0-10 cm and 10-20 cm soil layer of loamy meadow chestnut soil were 28.89 mg/100 g and 26.19mg/100 g, which were the highest in heading stage; 2.46 mg/100 g and 1.21mg/100 g in September 15 were the lowest in 2013. Soil microbial C in 0-10 cm and 10-20 cm soil layer of chestnut soil in 2014 were 36.83mg/100 g and 20.62mg/100 g in June.25, which were the highest; 6.79 mg/100 g and 5.10mg/100 g in Sep.25 were the lowest.2. The result of 2013 and 2014 show that no-tillage active microbe amount in 0-10 cm layer of soil were higher than 10-20 cm in chestnut soil. Active microbe amount of no tillage and sub soiling in 0-10 cm layer of soil were higher than 10-20 cm in loamy meadow chestnut soil, 10-20 cm layer of soil has higher active microbe amount in conventional tillage. No tillage chestnut soil 0-10 cm layer of soil active microbe amount in seedling stage and tillering stage were 20.62 mg/kg and 15.57mg/kg, which significantly higher than the conventional tillage, 9.17 mg/kg and 8.79mg/kg. Active microbe amount in conventional tillage was the lowest in the 5 treatments in jointing stage that every treatment got the lowest active microbe amount. The highest active microbe amount of loamy meadow chestnut appeared heading stage, anastomosed with the fast development of oat. The effect of environment was bigger to soil active microbe amount.3. The soil respiration rate in field displayed a changing pattern of “U” form under various tillage treatments in chestnut soil and loamy meadow chestnut soil in 2013 and 2014. The soil respiration in 0-10 cm layer of soil under no tillage in chestnut soil was 0.40mg/(kg·h) in October first, the highest soil respiration rate. The soil respiration rate under conventional tillage in October 15 was the highest soil respiration rate,it was 0.21 mg/(kg·h). The soil respiration in 0-10 cm layer of soil under no tillage in loamy meadow chestnut soil has higher than others tillage. The soil respiration rate under no tillage in seedling stage and jointing stage were 0.84 mg/(kg·h) and 0.52 mg/(kg·h),which were 1.63 and 1.58 times the soil respiration at the same time under conventional tillage. The soil respiration in 0-10 cm layer of soil under no tillage in chestnut soil in 2014 has obviously advantage,the peak appears June 25 and July 25,0.39 mg/(kg·h) and 0.57mg/(kg·h), which were 1.63 and 1.37 times the soil respiration synchronization under conventional tillage. The soil respiration in 0-10 cm layer of soil in loamy meadow chestnut soil peak appears seedling stage(June 15),0.66 mg/(kg·h) under no tillage,0.56 mg/(kg·h) under subsoiling tillage and 0.34mg/(kg·h) under conventional tillage, is respectively 5.15 times,6.66 times and 4.07 times what in September 5.4. The soil respiration quotient in chestnut soil in 2013 showed under no tillage,sub soiling tillage and conventional tillage, the soil respiration quotient in 0-10 cm layer of soil were higher than 10-20 cm layer in earlier oat growing stage, and the soil respiration quotient in later earlier oat growing stage were contrary to earlier oat growing stage. The soil respiration quotient in loamy meadow chestnut soil changed smoothly, and had a substantial increase after harvest, mark a high activity stage of soil microorganism. The soil respiration quotient in 0-10 cm under conventional tillage was higher than no tillage. The soil respiration quotient in 0-10 cm layer of chestnut soil under conventional tillage stayed high level, peak appeared in July 25,was 6.79,is respectively 3.03 times no tillage,1.83 times sub soiling tillage,4.76 times plowing after no tillage and 3.44 times plowing after sub soiling. The soil respiration quotient in loamy meadow chestnut soil in 0-10 cm goes up first and goes down then. Soil microorganism consume large of C to build cells at the earlier oat growing stage.5. The results show that co- tillage and soil type determines the weed community. Higher weed density in sub soiling tillage in chestnut soil, 741.33/m2, was 3.18 and 5.35 times no tillage and conventional tillage.High weed density under no tillage in oat seedling stage loamy meadow chestnut soil was lay the foundation for the weed community succession. Weed community structure in the region to foxtail(Setaira viridis) based, relative density was above 50%. DGM of chestnut soil was 0.851, the highest. No tillage of loamy meadow chestnut soil had highest diversity index. Chestnut soil oat fresh production in no tillage was 957.08kg/hm2, 69.84% of conventional tillage oat fresh production, and the weed fresh production in no tillage was 1.88 times the weed fresh production in conventional tillage. Loamy meadow chestnut soil oat fresh production in sub soiling tillage was 1122.41kg/hm2, respectively 1.72 times no tillage and 1.30 times conventional tillage, weed fresh production in sub soiling tillage was 50.63% of and no tillage 0.76% of conventional tillage. Long-term no-till farmland natural evolution of plant communities, build capacity characteristics of perennial weeds, and tilling with lower density of annual weeds, shallow bit of perennial weed eradication inspire deep bit of perennial weeds features.6. Soil hardness in no tillage of chestnut soil and loamy meadow chestnut soil significantly higher than soil hardness in sub soiling and conventional tillage and which increased while the depth deepen. Catcher Yan 0-20 cm layer of soil average soil hardness under no tillage of chestnut soil was 27.70kg/cm2, respectively 2.51 times what in sub soiling and 4.24 times what in conventional tillage. Catcher Yan 0-20 cm layer of soil average soil hardness under no tillage of loamy meadow chestnut soil was 20.95 kg/cm2, respectively 2.09 times what in sub soiling and 4.16 times what in conventional tillage. The change range of soil hardness in 0-5cm layer of soil was less than subsurface soil.7. Chestnut soil 0-20 cm layer of soil average soil bulk density of 5tillage methods in seedling stage were higher than sowing date, due to mechanical sowing. Basically the soil bulk density in no tillage was the highest. Whole level of loamy meadow chestnut soil bulk density was less than chestnut soil bulk density, related to light soil texture. Conventional tillage decreased subsurface soil bulk density and increased upper soil bulk density. The soil bulk density of 0-5cm layer of soil under no tillage and sub soiling were 1.07 g/cm3 and 1.17 g/cm3 harvest time, compare with which in sowing stage reduced 8.59% and 1.80%.Compared with soil bulk density in conventional tillage in sowing stages, soil bulk density in harvest time was 1.15 g/cm3, increased 4.91%.8. No tillage increased soil water storage in the beginning of oat growing periods. Loamy meadow chestnut soil water storage of 0-80 cm layer of soil outclasses that in chestnut soil. The average water content in long term sub soiling tillage was the maximum that was 10.41%, which in sowing time in plowing soil layer of chestnut soil, the average water content in long term conventional tillage was the second, which was 9.61%.The water consumption and the water consumption intensity of chestnut soil and loamy meadow chestnut soil were related to the rainfall. The height of oats was low because of the drought in heading stage. The WUE in conventional tillage was most in 5 tillage methods. Drought in oat growth period makes soil water shortage was the reason that reduction of oat production. |
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