黄土旱塬区平衡施肥下不同土壤耕作模式的蓄水纳墒及作物增产增收效应研究

【目的】黄土旱塬半湿润易旱区是典型的雨养农业区,多数一年一熟或两年一熟制,冬小麦和春玉米是该区主要的粮食作物,平衡施肥是主要的施肥方式。多年研究和生产实践证明,建立与不同作物轮作方式相配套的土壤轮耕技术体系,可以为作物生长发育创造良好的土、 肥、 水、 气、 热的土壤环境条件,保持农田生态健康发展,促进作物增产增收。本文在当地平衡施肥条件下,通过多年耕作模式定位试验,研究在平衡施肥条件下,不同土壤耕作模式对休闲期和作物生育期0200 cm土层蓄水纳墒状况、 作物产量及其经济效益的影响,为黄土旱塬半湿润易旱区建立在一定肥力水平下与作物轮作体系相配套的土壤轮耕模式提供理论依据。【方法】选择位于黄土旱塬半湿润易旱区腹地的陕西省合阳县甘井镇一年一熟旱作冬小麦春玉米轮作田为试验区,采用免耕、 深松和翻耕3种土壤耕作方法组成4种土壤轮耕模式,即: 翻耕免耕翻耕免耕(RT1); 深松翻耕深松翻耕(RT2); 免耕深松免耕深松(RT3); 免耕翻耕深松免耕(RT4); 以连年翻耕(CK1)、 连年深松(CK2)和连年免耕(CK3)为对照,通过连续4年(2007~2011年)定位试验,研究平衡施肥条件下的7种土壤耕作模式对冬小麦春玉米轮作田0200 cm土层土壤贮水量、 土壤水分含量、 作物籽粒产量、 水分利用效率(WUE)和经济效益的影响。【结果】 1)在土壤休闲期,RT3模式下0200 cm土层土壤贮水量最高,其次是RT2。与对照组相比,4种轮耕模式0200 cm土层土壤贮水量均高于CK1; RT3显著高于CK3,但与CK2差异不显著。0200 cm土层土壤剖面含水量,亦以RT3模式最高。2)在冬小麦生育期,0200 cm土层土壤贮水量和土壤含水量,RT3和CK2模式的较高。3)在春玉米生育期,0200 cm土层土壤贮水量和土壤含水量RT3和CK3较高。4)不同耕作模式的作物籽粒产量、 水分利用效率(WUE)和经济效益,以RT2和CK2模式最高。四年平均结果RT2处理较CK1、 CK2和CK3处理增产10.2%、 3.6%和17.1%,增收23.6%(P0.05)、 6.8%(P0.05)和28.3%(P0.05),提高WUE 9.7%(P0.05)、 4.3%和18.6%(P0.05)。【结论】年际间轮流进行深松和翻耕(RT2)处理,虽然其在土壤蓄水保墒效应方面略低于年际间轮流进行免耕和深松(RT3)和连年深松(CK2)处理,但可获得最佳增产增收效果和最高水分利用效率; 连年深松能够增加水分入渗,保护土壤,增加蓄水能力,但产量和经济效益不如RT2处理,也是该区比较适宜的耕作方法。根据实际状况,在平衡施肥条件下的一年一熟作物轮作区,应推荐深松翻耕的轮耕或连年深松的耕作模式。

Study on soil water storage,crop yields and incomes under different soil tillage patterns with balance fertilization in the Loess Dryland region

Objectives] The semi-humid and prone-to-drought Loess Dryland is a typical rain fed agricultural region, where the mostly common crop system is once a year or once every two years. Reasonable rotation of tillage systems is important in maintaining the sustainable development of farmland ecosystem, the study on which will provide base for efficient crop production. Methods] A long-term field experiment was conducted to investigate the effects of tillage patterns on yields, water use efficiency (WUE) and economic benefits of winter wheat and spring maize from 2007 to 2011 in Heyang County, Shaanxi Province. The tillage pattern treatments included:ploughing→no-tillage →ploughing →no-tillage (RT1), subsoiling→ ploughing→ subsoiling→ ploughing (RT2), no-tillage→ subsoiling→ no-tillage→ subsoiling (RT3), no-tillage→ ploughing→ subsoiling→ no-tillage (RT4), and ploughing in 4 years (CK1), subsoiling in 4 years (CK2), 3 no-tillage in 4 years ( CK3) for comparison propose. The soil water storage and water content in the 0 -200 cm soil layer, the crop yields, water use efficiency and economic benefits were measured. Results] 1) During the fallow period, the highest soil water storage was in RT3, followed by RT2. The soil water storage in all the four treatments was significantly higher than in CK1, that in RT3 was also significantly higher than in CK3, and the difference between CK2 and RT3 was not significant. The highest soil water content was also found in RT3. 2) During winter wheat growth period, all soil water storage and soil water content in RT3 and CK2 were higher than in other treatments. 3) During spring maize growth period, both the soil water storages and contents in RT3 and CK3 were higher than in other treatments. 4) Both RT2 and CK2 showed the best effects in increasing crop grain yields, water use efficiencies and economic benefits. Compared with CK1, CK2 and CK3, the four years’ average crop grain yields in RT2 increased by 10. 2% , 3. 6%and 17. 1% , the net incomes by 23. 6% , 6. 8% and 28. 3% , and WUE by 9. 7% ( P < 0. 05), 4. 3% and 18. 6% (P < 0. 05), respectively. Conclusions] Although the RT2 is not the best in saving soil water, it is best in improving WUE, crop yields and economic benefits. CK2 produces the highest water infiltration, water-holding capacity and soil-protecting capacity, although its crop yields is not as high as RT2. Considering the local conditions, RT2 and CK2 are recommended as suitable soil tillage patterns in the tested dry plateau area.