| The Weibei dryland, located at north of Guanzhong Plain and the south part of the Loess Plateau. The soil deep, solar-thermal resources abundant, but the lack of water, rainfall, and uneven distribution, is a typical rain fed agriculture region. In order to explore the effects of soil water storage, soil fertility and crop yield increasing of conservation and rotational tillage patterns, a 8-year on-site conservation tillage experiment with three rotational tillage treatments. Tt includes NT/ST(no-tillage in the first year, subsoiling in the second year, again no-tillage followed by alternating the next year), ST/CT(subsoiling in the first year, conventional tillage in the second year, again subsoiling followed by alternating the next year),CT/NT(conventional tillage in the first year, no-tillage in the second year, again conventional tillage followed by alternating the next year), and as well as three continuous tillage treatments, includes continuous no-tillage, continuous subsoiling, continuous conventional tillage. They were conducted under three kinds fertilizion(balanced fertilization, conventional fertilization, and low fat) treatment in wheat and maize rotation field of Heyang county, Shaanxi province, from 2007 to 2015. The results showed as following:1. Effects of different tillage treatments on major soil physical properties in wheat-maize rotation fieldThree kinds of rotational tillage could improve soil bulk density, porosity and field capacity, will help improve soil moisture conservation, and in NT/ST rotational tillage process is best.Under different tillage in the water macro-aggregate content(WR0.25) of NT/ST were shown the highest value in 0-40 cm soil layer, and with the continuous CT/CT were significantly different(P<0.05).Compared with the previous test and continuous tillage plowing, index of unstable aggregates(ELT) of NT/ST rotational tillage decreased significantly 0.8%-1.7% and 0.5%-1.8% in 0-40 cm soil layer(P<0.05). NT/ST was higher average soil water storage in 0-200 cm soil layer than ST/CT and CT/NT treatments two years of 2014 winter-wheat and 2015 spring-maize, Compared with continuous conventional tillage, average soil water storage capacity under NT/ST、CT/NT and ST/CT increased by 14.0mm, 5.8mm and 1.8mm, respectively. In fallow period of 2014—2015 year, average soil water storage capacity showed NT/ST>CT/NT>CT/CT>ST/CT.2. Effects of different fertilization and tillage treatments on soil nutrients content in wheat-maize rotation fieldBalanced fertilization increased the organic matter of soil by3.5% and 5.7%, increased the total soil nitrogen by3.4% and 9.7%, compared with conventional fertilization and low-fat in winter and wheat rotation field. Compared with conventional fertilization and low fat, soil organic matter of spring-maize increased 10.2% and 7.8% under balanced fertilization, respectively; total soil nitrogen increased by 5.9% and 3.9%, respectively. In balanced fertilization level, winter-wheat and spring-maize under rotational tillage than the continuous CT/CT 0-60 cm soil average soil total N increased by 11.7%-14.9% and 6.7%-10.0%, respectively.3. Effects of different fertilization and tillage treatments on leaf nutrient content of crop plantsCompared with low fertility treatment, conventional and balance fertility treatment of the average soluble sugar content of winter-wheat increased 23.0% and 14.5%, respectively. And 6 tillage systems, ST/CT and NT/ST rotational tillage of wheat the average soluble sugar content than the CT/CT increased 14.9% and 10.7%, respectively; NT/ST average soluble sugar content of spring maize than continuous NT / NT and CT/CT increased by 16.7%-20.2% and12.4%-15.8%, respectively. Three kinds of rotational tillage showed a higher leaf total nitrogen and total phosphorus than CT/CT treatment in different fertilization, was 11.2%-19.6% and 4.8%-13.4% higher than CT/CT treatment under balance fertilization, respectively; increase by 12.8%-14.6% and13.3%-19.6% in conventional fertilization, respectively. Comparing with continuous CT/CT tillage, average leaf total nitrogen of spring maize under CT/NT, NT/ST and ST/CT treatment was increased 18.4%, 17.3% and 10.8%, respectively.4. Effects of different fertilization and tillage treatments on agronomic traits and photosynthetic characters of cropBalanced fertilization, low-fat and conventional fertilization NT/ST rotational tillage comparing CT/CT average height growth of winter wheat increased by 17.8%, 10.1% and 14.2%, respectively; average height growth of spring wheat increased by 10.0%、16.4% and 10.6%,respectively.Compared with CT/CT, the average plant dry weight of winter wheat and spring maize under three rotational tillage patterns increased 30.5%-44.0% and 12.0%-16.2%, respectively. The winter wheat and spring maize chlorophyll content of three kinds rotational tillage under balanced fertilization increased by3.6%-6.1% and 11.2%-18.2%, respectively, than CT/CT. In the balanced fertilization level, the average rate of photosynthesis and transpiration rate in the growth period of winter and wheat rotational tillage patterns are higher than the continuous cultivation; the average rate of photosynthesis in the growth period of spring maize of NT/ST and ST/ST under balanced fertilization were the highest, the average transpiration rate in NT/ST and CT/NT value best result.5. Effects of different fertilization and tillage treatments on crop yield, WUE and economic benefits of winter-wheat and spring-cornCompared with low fat, balance and conventional fertilization treatments of wheat spike number increased11.1% and 9.6% respectively. Balanced fertilization, three kinds of crop rotation wheat kernel number showed NT/ST> ST/CT> CT/NT, and the difference was significant(P <0.05); Compared with CT/CT, NT/ST increased significantly by 16.2% in wheat 1000-kernel weight. Balanced fertility and conventional fertility than low-fat significantly increased spikes and 1000-kernel weight of spring maize; and compared with conventional fertility significantly, Balance fertility and low fertility significantly increased kernel number. Compared with low fertility, yield of wheat under balance fertility and conventional fertility increased by 7.2% and 5.1%, respectively; increasing yield of maize were 7.2% and 5.8%. And in balanced fertilization, yield of wheat and maize under NT/ST treatment was increased 14.4% and 8.9% than continuous conventional tillage separately. Compared with low fertility, water use efficiency of winter wheat was increased 11.2% and 5.8% under balance fertility and conventional fertility, respectively; and spring maize water use efficiency increased by 7.7% and 11.5%, respectively. Average water use efficiency under three fertilizations and NT/ST rotation tillage comparing CT/CT, winter wheat and spring maize increased by 22.5% and 19.9%, respectively. Compared with continuous conventional tillage, average net income of NT/ST tillage pattern was increased 1997 yuan/hm2 and 1362 yuan/hm2 in winter wheat and spring maize, respectively.In conclusion, the soil physical properties, soil fertility, soil physical structure improving, crop quality and economic benefits under balance fertilition and no-tillage / subsoiling tillage treatment, it was the best one among six tillage patterns. So balance fertility and no-tillage / subsoiling tillage is a more appropriate way of fertilization and rotational tillage pattern for the wheat'maize rotation field in Weibei dryland. |
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