沟垄二元覆盖对渭北旱塬区土壤肥力及玉米产量的影响

探讨沟垄二元覆盖对旱地土壤肥力及作物生产力的影响,对完善半湿润区作物微集水栽培技术具有重要的理论和实践意义。2007—2011年在渭北旱塬进行5年定位试验,设置垄上覆地膜,沟内分别覆普通地膜、生物降解膜、玉米秸秆、液体地膜和沟不覆盖等不同沟垄覆盖模式,以传统平作为对照。结果表明,2011年春玉米收获后各处理土壤有机质及速效养分含量随土层的加深而降低,与2007年试验处理前相比,沟垄二元覆盖各处理土壤养分含量明显增加,而垄覆地膜+沟不覆盖和传统平作处理有所下降。垄覆地膜沟覆秸秆处理0~20 cm层土壤有机质、碱解氮、有效磷和速效钾含量均显著高于对照,垄覆地膜沟覆地膜和垄覆地膜沟覆生物降解膜处理有机质和碱解氮含量较对照有所增加,而其有效磷和速效钾含量显著增加。20~60 cm层土壤有机质和速效养分含量各沟垄二元覆盖处理均略高于对照。各沟垄覆盖处理表层(0~20 cm)土壤脲酶、磷酸酶和蔗糖酶活性均较对照增加,且以垄覆地膜沟覆秸秆处理土壤酶活性最高,垄覆地膜沟覆生物降解膜和垄覆地膜沟覆地膜处理次之。垄覆地膜沟覆生物降解膜、垄覆地膜沟覆地膜和垄覆地膜沟覆秸秆处理较对照显著增产41.1%、42.1%、39.3%,水分利用效率显著提高38.0%、39.6%、37.0%。在渭北旱塬区进行沟垄二元覆盖对提高土壤肥力、酶活性及春玉米产量和水分利用效率有显著提高作用,以垄覆地膜沟覆秸秆处理最佳,垄覆地膜沟覆地膜和垄覆地膜沟覆生物降解膜次之。可见,垄覆地膜沟覆地膜、生物降解膜或秸秆的沟垄全覆盖种植在渭北旱塬雨养农业区春玉米生产栽培具有一定的可行性和应用价值。

Effects of Dual-mulching of Ridge and Furrow on Soil Fertility and Maize Yield in the Weibei Tablelands

Objectives]A five-year field experiment was conducted between 2007 and 2011 in the Weibei tablelands of Shaanxi,China to determine effect of different patterns of dual-mulching of ridge and furrow on soil fertility(soil organic matter and available nitrogen,phosphorus,potassium contents), enzyme activity(urease,phosphatase and sucrase)and crop productivity(maize yield and water use efficiency)in an attempt to provide some important theoretical and practical basis for perfecting micro-catchment crop cultivation in the sub-humid areas.Methods] In a tract of farmland under the ridge and furrow rainwater harvest system(RFRHS),ridges were covered with plastic film and furrows mulched with common plastic film,bio-degradable film,maize straw or liquid film,or left uncovered,and a tract of flat farmland under conventional cultivation without mulching,which is popular among local farmers,was used as control. Results] After the spring maize was harvested in 2011,soil organic matter and available nutrients in all the treatments decreased in content with soil depth. Soil nutrients in the dual-mulching treatments obviously increased in content when compared with the initial background value in 2007,but decreased in the treatment that had ridges mulched and furrows uncovered and the control. The treatment that had ridges mulched with plastic film and furrows mulched with straw was significantly higher than the control in content of soil organic matter,alkalytic nitrogen,available phosphorus and readily available potassium in the 0~20 cm soil layer,and the treatment that had both ridges and furrows mulched with plastic film and the treatment that had ridges mulched with plastic film and furrows with bio-degradable film were somewhat higher than the control in content of soil organic matter alkalytic nitrogen,but significantly higher in content of available phosphorus and readily available potassium. All the dual-mulching treatments were slightly higher than the control in content of soil organic matter and available nutrients in the 20~60 cm soil layer,and in activity of urease,phosphatase and sucrase in the 0~20 cm soil layer,too. The treatment that had ridges mulched with plastic film and furrows with straw was the highest in activity of soil enzymes,and followed by the treatment that had both ridges and furrows mulched with the plastic film and the treatment that had ridges mulched with plastic film and furrows with bio-degradable film. Dual-mulching significantly increased maize yield water use efficiency in the region. The treatment that had ridges mulched with plastic film and furrows with bio-degradable film,the treatment that had both ridges and furrows mulched with plastic film and the treatment that had ridges mulched with plastic film and furrows with straw was 41.1%,42.1% and 39.3%, respectively,higher than the control in maize yield and 38.0%,39.6% and 37.0% in water use efficiency.Conclusions]The dual-mulching technology has been demonstrated as an effective practice to improve soil fertility,promote soil enzyme activity and increase crop yield and water use efficiency in the Weibei tablelands. In terms of the effect,the treatment that has ridges mulched with plastic film and furrows with straw ranks first,and is followed by the treatment that has both ridges and furrows mulched with plastic film and the treatment that has ridges mulched with plastic film and furrows with bio-degradable film. Apparently, the technology is feasible and worth extrapolating for spring maize production in the rainfed agricultural zones of the Loess Plateau,China.