保护性耕作对黑河流域农田土壤水分利用的影响

为了探讨保护性耕作节水、 增产潜力及其在黑河流域的适应性,设计20 cm留茬(NS20)、 20 cm留茬压倒(NPS20)、 40 cm留茬(NS40)、 40 cm留茬压倒(NPS40)和传统耕作(CT)5个处理,研究了保护性耕作对黑河流域农田土壤含水量、 产量和水分利用效率(WUE)的影响.结果表明:相对传统耕作,保护性耕作增加了土壤贮水量:在2003年和2004年休闲期结束后,NPS40、 NS40、 NS20和NPS20表层0~30 cm土壤贮水量较CT分别增加30.22%、 27.29%、 20.92%、 13.64%和48.32%、 38.90%、 29.85%、 23.28%;2004、 2005两年播种期0~5 cm土壤含水量NPS40、 NS40、 NPS20和NS20较CT分别增加37.29%、 37.10%、 21.49%、 41.90%和33.99%、 40.17%、 8.90%、 38.44%;播种到拔节期留茬高度越大,土壤贮水量越多,在相同高度的留茬处理中,干旱年份压倒处理保水效果较好,降雨相对较多的年份立茬处理保水效果较好;拔节后各层土壤贮水量之间差异减小.保护性耕作增加作物产量和水分利用效率,尤其是NPS20,2004年和2005年产量和WUE较传统耕作分别增加53.08%、 5.85%和52.04%、 7.30%.

Effects of Conservation Tillage on Soil Water Regimes and Water Use Efficiency in Farmland of Heihe River Basin in Northwest China

Shortage of water resources and extreme drought limited crop production in Heihe River Basin in Northwest China. The concerned areas are also affected by serious wind erosion, and intensive tillage of conventional agriculture has worsened the situation. Therefore, conventional tillage (CT) and four conservation tillage were studied to analyze the effects of different tillage on soil water storage dynamics, soil moisture profile of the key growth period, grain yield and water use efficiency (WUE) through field experiment implemented in Zhangye from 2003 to 2005. The aim of the research is to identify a suitable conservation agriculture practice for this area. The results showed that conservation tillage increased the soil water storage compared with that of the conventional tillage. At the end of fallow stage, soil water storage of no tillage with 40 cm pressed stubble (NPS40), no tillage with 40 cm standing stubble (NS40), no tillage with 20 cm standing stubble (NS20) and no tillage with 20 cm pressed stubble (NPS20) in 0-30 cm soil layer was increased by 30.22%, 27.29%, 20.92% and 13.64% in 2003, and 48.32%, 38.90%, 29.85% and 23.28% in 2004, compared with that of CT. Soil water content in 0-5 cm soil layer of NPS40, NS40, NPS20 and NS20 was increased by 37.29%, 37.10%, 21.49% and 41.90% in 2004, and 33.99%, 40.17%, 8.90% and 38.44% in 2005 compared to the conventional tillage at sowing time. Conversation tillage changed the soil water supplying characteristics that could supply more water for crop growth and development under the conditions of water shortage, while saving more for coming stage when soil water was sufficient. Conservation tillage increased grain yield and WUE which was increased by 53.08% and 5.85% in 2004 and 52.04% and 7.30% in 2005 in NPS20 compared to the conventional tillage.