Supported by the National Natural Science Foundation of China(Nos.41271293, 41302222)
为探讨开垦对典型黑土表层土壤压缩与回弹行为的影响，以未经开垦天然次生林和开垦年限为17 a、30 a、40 a耕地的表层(0~10 cm)土壤为研究对象，采用快速固结试验方法，研究了土壤压缩与回弹过程中土壤孔隙比(e)、压缩指数(Cc)、压缩系数(a)和回弹指数(Cs)的变化。结果表明：土壤孔隙比(e)、压缩指数(Cc)、压缩系数(a)和回弹指数(Cs)随着开垦年限的增加而降低，Cc、a、Cs变化范围分别为0.252~0.426、0.002 04~0.003 70 kPa-1、0.041~0.070；未经开垦天然次生林地土壤Cc、Cs显著高于耕地土壤(p<0.05)；Cc、a、Cs与容重均呈极显著负相关(p<0.01)，与有机质含量呈极显著正相关(p<0.01)。土壤压缩性与回弹能力随着开垦年限的增加逐渐降低，容重、有机质含量对其影响最大。
In the black soil region of Northeast China, the issue of the soil getting more and more compact due to the extensive use of farming machines has been arousing more and more concerns among the people. Soil compaction has been considered one of the main causes of degradation of agricultural soils worldwide, because it reduces soil porosity and water infiltration, while enhancing soil intensity and soil consistence, which in turn impede root penetration into the soil and consequently reduce land productivity. Despite of this, little has been done on mechanical properties of compression and rebound of black soil typical of Northeast China. It is, therefore, essential to explore compression behavior of the soil for prediction of possible changes in soil structure under the pressure of farming machines. To explore effects of reclamation in mechanical properties of compression and rebound of the black soil, plots of black soil fields different in reclamation history, i.e. 17 (Plot 17), 30 (Plot 30) and 40 (Plot 40) years and un-reclaimed natural secondary forest land (Plot 0), were cited for soil sampling using a ring sampler, 2.00 cm high and 6.12 cm in diameter and the soil samples were analyzed for soil void ratio, compression index, compression coefficient, and rebound index with a fast oedometer. Results show that soil void ratio, compression index, compression coefficient and rebound index all went down with the cultivation going on. During the compression process, Plot 0 was obviously higher than Plots 17, 30 and 40 in soil void ratio (p<0.05); Plot 17 higher than Plots 30 and 40 (p<0.05); and Plot 30 did not differ much from Plot 40. And during the rebound and recompression phase, the four plots displayed a variation pattern similar to that during the compression process. Compression index, compression coefficient and rebound index of the soil varied from 0.252 to 0.426, 0.002 04 to 0.003 70 kPa-1, 0.041 to 0.070, respectively. Plot 0 was significantly higher than the other three plots (p<0.05), and Plot 17 higher than Plots 30 and 40 in compression index (p<0.05), while no significant difference was found between Plots 30 and 40. However, the plots showed a different trend in soil compression coefficient. Plot 0 and Plot 17 was significantly higher than Plots 30 and 40, but the former two did not differ much. Plot 0 was still significantly higher than all the other three in rebound index (p<0.05), but among the latter three, only Plot 17 was significantly higher than Plot 40 (p<0.05). Besides, it was also found that with farming cultivation going on, soil organic matter content decreased while soil bulk density increased, and both of the indices were found somewhat related to compression index, compression coefficient and rebound index of the soil. Organic matter content was positively related to compression index (r=0.893), compression coefficient (r =0.733) and rebound index (r=0.803), while bulk density was negatively related to compression index (r=-0.884), compression coefficient (r=-0.904) and rebound index (r=-0.840); However, soil clay content did not seem to be related to compression index, compression coefficient and rebound index of the soil. Moreover, both soil compression index and soil rebound index were in significant positive relationship with soil compression coefficient (p <0.05), and soil compression index was in extremely significant positive relationship with soil rebound index (p <0.01). In conclusion, reclamation affects soil compactness significantly, and with mechanical farming cultivation going on, soil compactness increases in degree, while compressibility and rebound capacity of the black soil decrease. Obviously, long-term mechanical farming cultivation decreases soil organic matter content and increases soil bulk density, which is believed to be the major cause leading to the decline of soil compressibility and rebound capacity.
韩少杰,王恩姮,陈祥伟,罗 松.开垦对黑土表层土壤压缩—回弹行为的影响[J].土壤学报,2016,53(3):646-653. DOI:10.11766/trxb201511160357 HAN Shaojie, WANG Enheng, CHEN Xiangwei, LUO Song. Effects of Tillage on Compression and Rebound Behavior of Topsoil in Black Soil Region[J]. Acta Pedologica Sinica,2016,53(3):646-653.复制