“玉米田养鹅”农田生态系统下的土壤温度影响机制

Influence mechanism of the farmland ecosystem of“Raising geese in corn field”on soil temperature

为了解农牧一体化下"玉米田养鹅"生产模式的土壤温度影响机制,通过对比试验方法进行田间试验,结果表明:玉米田养鹅处理杂草群落平均密度为171.33株/m^2,是对照密度(11.11株/m^2)的15.42倍,处理间差异极显著(P<0.01;n=9),该处理下杂草Shannon-Wiener多样性指数为1.76,Simpson多样性指数为0.77,均高于对照;玉米田养鹅处理的地上生物量为386.30g/m^2,是对照(5.67g/m^2)的68.13倍,处理间差异极显著(P<0.01;n=9),同时玉米田养鹅处理的盖度为90.56%,是对照(7.22%)的12.54倍,处理间差异极显著(P<0.01;n=9)。在白天土壤温度的变化过程中,玉米田养鹅处理较高的地上生物量和丰富的地表植被使得田间地下生物生理代谢活动旺盛,土壤呼吸作用增强,土壤CO2呼吸通量增加,高达308.64 mg/(m^2·h),显著高于对照的234.90mg/(m^2·h)(P<0.05;n=9)。因此,在试验期间白天光照不足,地表接受光照辐射有限的情况下,生物代谢活动产生的热量是影响土壤温度的主导因素,白天的土壤温度高于对照。在夜间土壤温度的变化中,玉米田养鹅处理5~15cm的土壤含水量为16.14%,显著高于对照1.27%(P<0.05;n=9),水的良好导热能力促进了土壤的散热,使得玉米田养鹅处理表层土壤夜间散热较快,以致夜间该处理下的土壤温度低于对照。因此,在"玉米田养鹅"模式生产过程的前期,生物代谢活动和土壤含水量是影响土壤温度变化的主要因素。

The principle of soil temperature change of agro-pastoral integration was studied in order to clarify factors and mechanism of soil temperature under ＂Raising geese in corn field＂ mode.Field experiments were conducted by using comparative method.The results showed that the mean density of weed communities in maize field was 171.33 plants/m^2,which was 15.42 times of the control density （11.11 plants/m^2）,and the difference between treatments was extremely significant （P〈0.01;n=9）.Shannon-Wiener diversity index was 1.76 and Simpson diversity index was 0.77,which were all higher than those in the control.The above ground biomass of maize field was 386.30 g/m^2,which was 68.13 times of control （5.67 g/m^2）,and the difference between treatments was extremely significant （P〈0.01;n=9）.The coverage of maize field geese was 90.56%,which was 12.54 times of that of control treatment （7.22%）,and the difference between treatments was extremely significant （P〈0.01;n=9）.The physiologic metabolic activities of underground biota and soil respiration were also enhanced during the daytime soil temperature change due to high above ground biomass and abundant surface vegetation.In addition,soil CO2 flux increased to 308.64 mg/（m^2·h）,which was 1.31 times higher than that in control （234.90 mg/（m^2·h））,and the difference was significant （P〈0.05;n=9）.During the test period,illumination was poor and surface radiation exposure was limited in the daytime.The light intensity of maize field goose was 5 488.89 Lx,the control treatment was 8 666.67 Lx.Soil temperature was mainly due to the heat generated by bio-metabolic activities,so the soil temperature during the day was higher than that in the control treatment;During night time,the soil water content in the 5-15 cm soil layer was 16.14%,which was significantly higher than that in control 1.27% （P〈0.05;n=9）.Good thermal conductivity of water promoted the heat of the soil and corn geese responded to surface soil heat faster at night.Eventually,the soil temperature at night was lower.In conclusion,biological metabolic activity and soil moisture content were the main factors affecting the soil temperature changes at preproduction stage of ＂Raising geese in corn field＂.