集雨种植下不同沟垄比对土壤呼吸的影响及其对水热因子的响应

为探明不同宽度沟垄集雨种植下土壤呼吸对土壤水热因子的响应机制,对比研究了沟垄比分别为20 cm∶40 cm(P40)、30 cm∶30 cm(P30)、40 cm∶20 cm(P20)的沟垄集雨种植和平作种植(CP)下冬小麦的土壤呼吸动态变化,及其与土壤温度和水分的关系.结果表明,4个处理的土壤呼吸速率在越冬期最低,返青期开始升高,扬花期前后达到峰值,之后逐渐降低.沟垄集雨处理土壤呼吸速率表现为P40P30P20,垄宽增加使呼吸速率提高1.2%~18.4%;苗期和越冬期,沟垄集雨种植提高了土壤呼吸速率,表现为P40P30P20CP,其中苗期3个沟垄集雨处理均显著高于CP(P0.05),越冬期P40处理显著高于CP;苗期和越冬期沟垄集雨种植提高了土壤温度,拔节期至成熟期CP土壤温度高于沟垄集雨处理;沟垄集雨种植能有效蓄水保墒,随着垄宽的增加集雨效果越好,苗期至拔节期降雨稀少,7.6 cm和12 cm土层土壤含水量均表现为P40P30P20CP.相关分析表明,土壤呼吸与温度的相关系数达极显著水平(P0.01),P40和P30的土壤呼吸与水分的相关系数小于P20和CP;水热双因子二次方程模型能解释呼吸变化的61.7%~74.1%,温度指数模型能解释50.3%~68.2%.本研究结果为沟垄集雨种植的生态效益评估提供理论依据.

Soil Respiration in Response to Different Ridge/Furrow Ratios and Its Relationship with Soil Moisture and Temperature Under Ridge-Furrow Planting Patterns

This study aimed to explore soil respiration in response to soil moisture and soil temperature subjected to different ridge/furrow ratios under various planting patterns. Traditional flat planting and three different ridge-furrow plantings with altering ridge/furrow ratios, i. e. 20:40 cm (P40); 30:30 cm (P30); 40:20 cm (P20), were performed in the present study. Soil respirations among different planting patterns were compared. Their relationships with soil moisture and soil temperature were also analyzed. The results showed that soil respiration flux of four planting patterns reached its minimum value during the wintering stage, started to rise during the returning green stage until it reached a peak value at the flowering stage, and decreased gradually when reaching the maturity stage. The magnitude of soil respiration flux in three ridge-furrow planting patterns followed this order: P40 > P30 > P20, which implied that increasing ridge width could improve soil respiration by 1.2%-18.4%. In addition, soil respiration fluxes of three ridge-furrow plantings patterns were significantly higher than those under conditional patterns during the seedling stage (P<0.05). The soil temperature of ridge-furrow planting patterns was higher than that of the conditional flat pattern from the seeding stage to the wintering stage, but was converse from the jointing stage to the maturity stage. Moreover, three ridge-furrow planting patterns have shown significant effect on preserving soil water storage in comparison with the conditional flat pattern. In general, increasing the width of the ridge increased soil water storage due to less rainfall from the seedling stage to the jointing stage. The correlation analysis indicated a positive and significant correlation coefficient between soil respiration and soil temperature (P<0.01). Correlation coefficients in case of P40 and P30 were higher than those in P20 and the conditional flat pattern. The quadratic model of two-factor soil moisture and soil temperature could explain 61.7%-74.1% of variations in soil respiration. The single factor of the soil temperature model could explain 50.3%-68.2% of variations in soil respiration. Those results could provide a theory basis for further evaluation of ecological effect on the ridge-furrow planting patterns.