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为了明确冻融作用是否有助于解决免耕或少耕带来的土壤容重增大等问题,我们在黑龙江省嫩江县鹤山农场进行不同含水量、不同容重的黑土冻融试验。结果表明:不同含水量的土壤(容重1.30gcm-3)在冻融作用后20cm内土壤容重基本减小,但减小幅度与含水量之间不是完全的正比关系。不同深度土壤容重的变化规律是:高含水量时,表层容重减小幅度较大,下层减幅相对较小;低含水量时,则相反。冻融作用对不同容重土壤(含水量30%)的表层容重影响较大,它使小容重土壤变得更加致密;使大容重土壤变得疏松。黑土区冻融作用对免耕带来的容重增大问题可以起到一定的减缓作用。
In order to clarify whether freezing and thawing can help solve the problem of increasing the bulk density of soil caused by no-tillage or tillage, we conducted freeze-thaw experiments of black soil with different water content and different bulk density at Heshan Farm, Nenjiang County, Heilongjiang Province. The results showed that the bulk density of soil with different water contents (bulk density 1.30gcm-3) basically decreased within 20cm after freezing and thawing, but the decrease range was not completely proportional to the water content. The variation of soil bulk density at different depths is: when the water content is high, the surface bulk density decreases a lot while the lower layer decreases a little, while the low water content, on the contrary. The freeze-thaw effect greatly affects the surface bulk density of soil with different contents of heavy water (30% water content), which makes the soil with smaller bulk density denser and loosens bulk soil. The freeze-thaw action in the black soil region can play a role in alleviating the problem of increasing bulk density caused by no-till.