东北主要类型旱田土壤持水特性研究

土壤持水特性是对土壤水分有效性的一种反映,不同土壤持水特性存在差异。为了解东北地区主要旱田耕地土壤的持水特性,本研究通过定点采样方法,在不同地区选择了典型的黑土、草甸土、白浆土、碱土、褐土5类旱田耕地土壤,通过压力膜法得出不同水柱压力下土壤水分实测值,并通过Van Genuchten和Garden模型进行模型拟合,相关性极显著,通过Van Genuchten绘制土壤水分特征曲线,从曲线看出,不同类型土壤持水特性存在差异,0～10 cm土层各土壤水分特征曲线差异大、曲线分散,草甸土、白浆土、碱土含水量在各压力下均处于较高水平,褐土最低,黑土居中; 10～20 cm土层土壤水分特征曲线在低吸力阶段差异仍较大,高吸力阶段差异小,褐土含水量最低,草甸土、白浆土、碱土趋于一致,黑土居中; 20～30 cm土层差异减小,褐土、碱土、黑土趋于一致;通过Garden模型计算土壤比水容量,不同水吸力下,褐土比水容量最高,其次是黑土,草甸土、白浆土和碱土比水容量较低,说明褐土和黑土释水能力强;土壤饱和含水量与土壤容重显著负相关,土壤有效持水库容与土壤大颗粒、土壤0. 02 mm的颗粒呈极显著负相关,与0. 02～2 mm的颗粒含量呈显著正相关;草甸土、碱土、白浆土饱和持水库容高,但有效库容低,与褐土、黑土相反。因此,提高土壤持水能力要根据土壤的物质特性提出对应措施。

Study on the water retention characteristics of the main types of soil in Northeast China

Soil water retention characteristics is a reflection of soil water availability.Water retention characteristics of different soils are different.In order to understand water retention characteristics of main upland cultivated soil in Northeast China,fixed point sampling method was used and 5 kinds of dry farmland soil types including black soil,meadow soil,albic soil,alkali soil,cinnamon soil were selected as the research object,the measured values of soil moisture under different water column pressure were obtained by pressure membrane method.The model was fitted by Van Genuchten and Garden model,and the correlation was very significant.The soil water characteristic curve drawn by Van Genuchten showed that the water retention characteristics of different types of soil were different.The soil moisture characteristic curve of 0~10 cm soil layer was different and the curve was dispersed.The water content of meadow soil,albic soil and alkaline soil was at a high level under all pressures,the cinnamon soil was the lowest,and the black soil was in the middle.The soil moisture characteristic curre in the soil layer of 10~20 cm soil was still very different in the low suction stage,and the difference in the high suction stage was small.The water content of cinnamon soil was the lowest,and meadow soil,albic soil and alkaline soil tended to be the same,and the black soil was in the middle.The differences of soil moisture characteristic curre in the 20~30 cm soil layer decreased and cinnamon soil,the alkaline soil and the black soil tended to be the same.Under different water suction,the specific water capacity of cinnamon soil,which was calculated by the Garden model,was the highest,followed by black soil,meadow soil,albic soil and alkaline soil.It showed that the water releasing ability of cinnamon soil and black soil was strong.There was a significant negative correlation between soil saturated water content and soil bulk density.The effective water retention capacity of soil was significantly negatively correlated with the large soil particles and the particles less than 0.02 mm in the soil.But it had a significant positive correlation with the particle content of 0.02~2 mm.The saturated water retention capacity of meadow soil,alkaline soil,albic soil were high,but the effective storage capacity was low.This was contrary to the cinnamon soil and the black soil.Improving soil water retention capacity requires corresponding measures based on the characteristics of the soil.