立式深旋松耕对西北半干旱区土壤水分性状及马铃薯产量的影响

Effects of vertical rotary sub-soiling on soil water characteristics and potato tuber yield in a semi-arid area of northwest China

合理耕作可增强土壤水分供给能力和促进作物根系发育,进而提高作物抗旱性和生产力,将是进一步挖掘半干旱区马铃薯产量和水分利用效率潜力的有效途径。在西北黄土高原半干旱区于2016-2017年设置定位试验,在全膜覆盖垄作模式下设计立式深旋松耕40cm(VRT)、深松耕40cm(DLT)和传统旋耕15cm(TT)3个处理,测定土壤容重、总孔隙度、毛管孔隙度、饱和含水量、毛管含水量以及田间持水量和萎蔫系数、生育期土壤含水量、马铃薯产量等,计算土壤有效贮水量、耗水量和水分利用效率等指标,研究立式深旋松耕对土壤物理性状、马铃薯产量和水分利用的影响。结果表明,VRT显著降低了0～40cm土层的土壤容重,较DLT和TT分别下降了10.8%～25.3%和11.2%～24.8%;土壤总孔隙度、毛管孔隙度分别提高了12.3%～23.7%和29.7%～46.6%,饱和含水量和土壤毛管含水量分别增加了26.1%～54.4%和38.8%～82.9%,萎蔫贮水量下降了11.0%～49.0%。与TT相比,DLT降低了20～40cm土层的土壤容重和萎蔫贮水量,显著提高了饱和含水量、毛管含水量、总孔隙度和毛管孔隙度。基于土壤物理性状和水分特性的优化,VRT在0～40cm土层的有效贮水量显著高于DLT和TT,分别增加了34.3%～136.9%和44.6%～75.2%,DLT较TT在20～40cm土层也有显著增加。较高的土壤有效贮水量促进马铃薯生长,并显著提高块茎产量,VRT分别较DLT和TT增产24.8%～156.8%和47.8%～41.0%,水分利用效率(WUE)分别提高18.9%～92.3%和19.2%～26.6%,干旱年份(2016)的增加幅度显著高于正常降水年份(2017)。因此,立式深旋松耕显著优化了土壤的水分特性,提高了土壤有效水含量,促进马铃薯发育,提高块茎产量和WUE,这一效果在干旱年份尤为明显,是适合于黄土高原半干旱区抗旱增产、水分高效的耕作方法。

The right tillage methods can improve the capacity of soil to supply water to crops and promote root development.This can result in better drought resistance of crops and higher productivity.Therefore,this is a promising strategy to increase the yield and water-use efficiency of potato(Solanum tuberosum)crops in a semiarid area.This study was conducted at the Dingxi Experimental Station of the Gansu Academy of Agricultural Sciences.The station is located in the northwest of Loess Plateau(Anding District,Dingxi,Gansu Province,104°36′E,35°35′N)at an altitude of approximately 1970 m.The field experiment was conducted under ridge-furrow planting and plastic-mulching conditions in 2016 and 2017.Potato(Longshu 10)was used as the material,and the three treatments included:1)vertical rotary sub-soiling to 40 cm depth(VRT);2)sub-soiling to 40 cm depth(DLT);and(3)traditional tillage to 15 cm depth(TT).The experimental design was a randomized block with three replicates,and the area of each plot was 10 m×6 m.The soil bulk density,soil total porosity,capillary porosity,soil saturation moisture content,capillary moisture content,field water capacity,soil wilted moisture content,total soil water content,and tuber yield were investigated.In addition,soil available water storage,evapotranspiration(ET),and water-use efficiency(WUE)were calculated to determine the effect of the different tillage treatments on soil water characteristics,potato tuber yield,and WUE.The results showed that VRT significantly decreased the soil bulk density;by 10.8%-25.3%and by 13.8%-24.8%as compared with DLT and TT,respectively.Compared with DLT and TT,VRT increased total soil porosity and capillary porosity by 12.3%-23.7%and 29.7%-46.6%,respectively,increased the soil saturation moisture content and capillary moisture content by 26.1%-54.4%and 38.8%-82.9%,respectively,and decreased the soil wilted moisture content by 11.0%-49.0%.Compared with the TT treatment,the DLT treatment resulted in lower soil bulk density and soil wilted moisture content,and higher soil saturation moisture content,capillary moisture content,total soil porosity,and capillary porosity.The optimized soil physical and hydrographic characteristics resulted in significant increases in soil available moisture in VRT(34.3%-136.9%higher than in DLT and 44.6%-575.2%higher than in TT).The soil available moisture content in the 20-40 cm soil layer was much higher in DLT than in TT.The significant increase in soil available water content in VRT resulted in increased potato plant growth(by 24.8%-156.8%),increased potato tuber yield(by 47.8%-41.0%),and increased WUE(by 18.9%-92.3%and 19.2%-26.6%),as compared with those in the DLT and TT treatments.The observed differences among the treatments were significant,and were greater in the drought year(2016)than in the normal year(2017).Consequently,VRT optimized the soil physical and hydrographic characteristics,increased soil available moisture,increased potato development and tuber yield,and improved WUE,with stronger effects in the drier year(2016).Thus,VRT is a promising method to improve drought resistance and increase the water-use efficiency of crops on the semiarid Loess Plateau.