横坡与顺坡垄作模式土壤中水及示踪Br-分布特征

Study on the Distribution Characteristics of Soil Moisture and Tracer Br-Under Transverse Ridge and Along-slope Ridge Planting Modes

针对坡耕地横坡、顺坡垄作模式土壤水分及溶质迁移过程的差异,采用田间模拟试验的方法,以坡度为7°的大豆坡耕地为研究对象,以Br-为示踪剂,监测不同垄作模式垄台、垄侧、垄沟各位置的土壤水分和Br-浓度,探究坡耕地横坡、顺坡垄作模式对土壤中水分迁移及可溶性养分分布的影响。结果表明:2种模式最大土壤体积含水量横坡垄作分布在10—20 cm土层,顺坡垄作分布在5—15 cm土层,证明横坡垄作对雨水的拦蓄作用。横坡垄作模式最大土壤贮水量位置在垄上侧的垄侧处,顺坡垄作模式在垄沟处。不同垄作模式下各土层土壤体积含水量变异系数在0—5,50—60 cm处较大,介于8.97~11.90,中间土层的变异系数较小,在0.91~8.76间波动。顺坡垄作20—60 cm土层中Br-沿坡向迁移现象明显,横坡垄作40—60 cm土层中Br-沿坡向发生迁移;2种垄作模式垄台和坡向下方位置(横坡∶垄侧;顺坡∶株间)的土壤Br-总量比值均约为3∶7,顺坡垄作垄台中心处Br-总量为横坡垄作的54.33%,说明横坡垄作可以减少土壤中Br-沿坡向迁移。研究成果为在顺坡垄作条件下将非吸附性养分施在垄侧处可减少其迁移流失,有利于提高作物对养分的利用效率。

In view of the difference of soil water and solute migration between transverse ridge planting and along-slope ridge planting modes in sloping farmland,a field simulation experiment was conducted to monitor soil water distribution and Br-concentrations distribution in different ridge planting modes,including ridge beds,ridge sides and furrows,taking the soybean sloping land with a slope of 7°as the research object and Br-as the tracer.To explore the effects of transverse and along-slope ridge planting modes on soil water migration and soluble nutrient distribution in sloping farmland.The results showed that the maximum soil water content of the two modes was distributed between the 10—20 cm soil layer in transverse ridge cropping and between the 5—15 cm soil layer in the along-slope ridge planting mode,which proved the effect of transverse ridge planting mode on rainwater storage.The maximum soil water storage was found in the ridge side on the upper side of the ridge under the transverse ridge planting mode,and that in the ridge and furrow under along-slope ridge planting mode.The variation coefficient of soil volumetric water content in each soil layer under different ridge planting patterns was larger in the range of 0—5 cm,50—60 cm,and was between 8.97 and 11.90.The variation coefficient of soil volumetric water content in the middle layer was smaller,and fluctuated between 0.91 and 8.76.The Br-ions migration along the slope direction was obvious in the soil layer of 20—60 cm under the ridge planting along the slope,while Br-ions migration occurred in the soil layer of 40—60 cm under the ridge planting on the transverse slope.The ratio of soil Br-ions total amount in the ridge of the furrow and the lower part of the slope(transverse ridge planting:side of the ridge;along-slope ridge planting:among the plant)was 3∶7 in the two ridge cultivation modes.The total amount of Br-ions in the center of ridge bed under the along-slope ridge planting modes was only 54.33%of that under transverse ridge planting mode,which could reduce the migration of Br-ions in soil along the slope.Based on the results of this study,it can be concluded that applying non-absorbable nutrients on the ridge side can reduce their migration and loss,which is beneficial to improve the utilization efficiency of nutrients by crops.