长期不同施肥方式对华北地区温室和农田土壤团聚体形成特征的影响

Effect of long-term fertilization on soil aggregate formation in greenhouse and farmland conditions in the North China Plain

  • 摘要: 土壤的团聚状况是土壤重要的物理性质之一,团聚体数量是衡量和评价土壤肥力的重要指标。施用有机肥是提高土壤有机碳(SOC)含量、促进土壤团聚体形成和改善土壤结构的重要措施。本文以华北地区曲周长期定位试验站的温室土壤和农田土壤为研究对象,运用湿筛法,对比研究施用化肥(NP)、有机肥加少量化肥(NPM)、单施有机肥(OM)3种施肥方式对温室和农田两种利用方式土壤水稳性团聚体含量、分布和稳定性的影响,以提示施肥措施对不同土地利用方式土壤水稳性团聚体特征的影响。结果表明:在温室土壤和农田土壤中,OM处理较NP和NPM处理显著降低了土壤容重,增加了土壤有机质含量(P < 0.05),且在0~10 cm土层中效果最为明显。其中在温室土壤0~10 cm土层,单施有机肥处理(OM1)的土壤容重为1.17 g·cm-3,分别较施用化肥(NP1)和有机肥加少量化肥(NPM1)处理降低12.0%和8.6%,OM1的土壤有机质含量为54.81 g·kg-1,较NP1和NPM1增加104.8%和35.7%;在农田土壤0~10 cm土层,单施有机肥处理(OM2)的土壤容重为1.19 g·cm-3,较施用化肥(NP2)、有机肥加少量化肥(NPM2)分别降低8.5%和7.0%,OM2的土壤有机质为22.67 g·kg-1,较NP2、NPM2分别增加23.1%和15.0%。温室土壤和农田土壤中,0~10 cm、10~20 cm和20~40 cm层土壤团聚体的平均重量直径(MWD)和几何平均直径(GMD)均为OM > NPM > NP;OM处理下水稳性团聚体的分形维数(D)值最低,NP处理下最大。OM处理显著降低0~20 cm土层内水稳性团聚体的D值,表层0~10 cm土层效果最为明显,土壤结构明显得到改善;相比农田土壤,温室土壤稳定性指标变化最为明显,团聚体结构改善效果最好。土壤有机质含量与 > 0.25 mm水稳性团聚体含量间呈极显著正相关关系(P < 0.001),说明土壤有机质含量越高, > 0.25 mm水稳性团聚体的含量就越高,土壤团聚体水稳性越强,土壤结构越稳定。因此有机施肥方式能在补充土壤有机碳库和有效养分含量的同时,显著增加土壤中大团聚体的含量及其水稳性,是提高华北平原农田土壤、尤其是温室土壤结构稳定性和实现土壤可持续发展的有效措施。

     

    Abstract: The status of soil aggregates is an important soil physical property and the amount of soil aggregates is a critical index for measuring and evaluating soil fertility. Organic fertilizer application is an essential measure for improving soil organic carbon (SOC) content, promoting soil aggregate formation and improving soil structure. A long-term experiment was conducted in greenhouse soil and in farmland soil under three fertilizer treatments in Quzhou County in the North China Plain in order to investigate the effects of different modes of fertilization on the content, distribution and stability of soil water-stable aggregates using the wet-sieving method under different land use types. Results indicated that continuous organic matter application (OM) significantly decreased soil bulk density and significantly increased soil organic matter content, compared with chemical fertilizer application (NP) and mixed organic manure with chemical fertilizer treatment (NPM) in both greenhouse and farmland soils (P < 0.05). This effect was obviously for the 0-10 cm soil layer. The bulk density of the 0-10 cm soil layer under greenhouse conditions with organic fertilize application treatment was 1.17 g·cm-3, which decreased respectively by 12.0% and 8.6% compared with those under chemical fertilizer and mixed organic manure with chemical fertilizer treatments. The content of organic matter in the 0-10 cm soil layer of greenhouse with organic fertilize application treatment was 54.81 g·kg-1, which increased respectively by 104.8% and 35.7% compared with those under chemical fertilizer and mixed organic manure with chemical fertilizer treatments. Also the bulk density of soil in the 0-10 cm layer of farmland with organic fertilize application was 1.19 g·cm-3, which decreased respectively by 8.5% and 7.0% compared with those under chemical fertilizer and mixed organic manure with chemical fertilizer treatments. The contents of farmland organic matter in the 0-10 cm soil layer with organic fertilize application was 22.67 g·kg-1, which increased respectively by 23.1% and 15.0% compared with those under chemical fertilizer and mixed organic manure with chemical fertilizer treatments. The mean weight diameter (MWD) and geometric mean diameter (GMD) of water-stable aggregates of both greenhouse and farmland soils changed in the following order: OM > NPM > NP. Fractal dimension (D) of water-stable aggregates under OM treatment was lowest while that under NP treatment was highest. Treatments with OM significantly decreased D value in the 0-20 cm soil layer, which effect was most obvious for the 0-10 cm soil layer where soil structure improvement was also very obvious. Compared with farmland soil, changes of soil stability indexes and the effects of aggregate structure were more obvious for greenhouse soil. The most significant correlation was between soil organic matter content and the content of > 0.25 mm soil aggregates, which indicated that the more soil organic matter, the greater stability the soil structure. In conclusion, the application of organic matter not only increased the content of soil organic matter and available nutrients, but also promoted the formation of macro-aggregates and improved aggregate stability. It was an effective measure to improve the stability of farmland soil, which also was good for sustaining soil development, especially for soils under greenhouse conditions in the North China Plain.

     

/

返回文章
返回