木霉制剂改良滨海盐渍土台田生态效应

生物改良滨海盐渍土是一种投资少、需时短、见效快、长期受益的环保生态型技术。通过田间试验将木霉制剂活性成分为木霉分生孢子,1×107(CFU)·g~(-1)]施用到滨海中度盐渍土台田(含盐量2.99 g·kg~(-1),砂壤土),对土壤改良台田试验区不同处理(施用木霉制剂和常规对照处理)及辅助试验区日光温室(含盐量0.98 g·kg~(-1),壤土)、滨海轻度盐渍土开垦田(含盐量1.75 g·kg-1,轻壤土)、滨海重度盐渍土河滩地(含盐量26.19 g·kg~(-1),砂壤土)的耕层土壤取样室内测定,探究木霉在滨海中度盐渍土台田施用的生态效应。滨海中度盐渍土台田木霉处理与对照处理相比,土壤紧实度提高177.04%,土壤水稳性团聚体数量(≥0.25 mm)提高265.78%,土壤含水率提高320.83%,土壤碱解氮、有效磷、速效钾和有机质含量分别提高96.14%、42.17%、105.65%和63.79%;土壤稀释法培养微生物,细菌、放线菌、真菌、固氮菌数量比对照分别提高170.95%、82.68%、152.17%和471.93%。滨海中度盐渍土台田木霉处理与滨海重度盐渍土河滩地比较,有利于植物生长的指标土壤紧实度、水稳性团聚体、有机质和微生物群落数量分别提高1.53倍、2.11倍、3.20倍和28.33倍,不利植物生长的水溶性盐下降96.60%;滨海中度盐渍土台田通过木霉制剂改良,土壤紧实度、总孔隙度、含水率、有效磷、有机质和微生物数量与滨海轻度盐渍土开垦田相比无显著差异;滨海中度盐渍土台田木霉处理后土壤容重降低、总孔隙度增加,与高产日光温室非盐渍化土壤相比接近。滨海重度盐渍土通过沙土抬高1.2 m筑田变为中度盐渍土,降盐效果较好,再通过加入生物改良措施提高土壤营养和有益微生物,优化土壤团粒结构,利于提高滨海中度盐渍土台田改良效率和质量,促进滨海中度盐渍土台田生态的改善。

Ecological effect of Trichoderma agent on platform field soil improvement in saline coastal area

Application of biological agents to improve saline soil is a relatively fast, economical, simple method with long-term effectiveness. Trichoderma spp. are free-living fungi that are highly active in interaction among root, soil and foliar environments. Biological agents application in agricultural systems is a potential method to ameliorate saline soil, eventually benefiting the environment or ecosystem by regulating soil physical and chemical properties and microbial population. In this study, broadcast granule preparation of Trichoderma agent (containing at least 1×107 colony-forming units of active ingredients for per gram dry weight) was applied to soil of moderately saline coastal platform fields to explore effect of Trichoderma agent on soil properties of moderately saline coastal platform field. Arable layers soils were sampled, which included moderately saline coastal platform field with (T1010) and without (CK) Trichoderma agent under peanut cropping (sandy loam soil with salt content of 2.99 g·kg-1), flood land in coastal saline area (sandy loam soil with salt content of 26.19 g·kg-1), reclaimed field in coastal slight saline area under continuous cotton cropping (light loam soil with salt content of 1.75 g·kg-1), non-saline solar-greenhouse soil under continuous tomato cropping (loam soil with salt content of 0.98 g·kg-1). All the plot samples were repeated four times, and the physical, chemical and biological properties tested in laboratory. The results showed that Trichoderma agent amended soil physical properties. Compared with CK, T1010 increased soil compaction by 177.04%, content of water stable aggregate of ≥0.25 mm by 265.78%, soil moisture content by 320.83%. In this study, soil chemical properties also changed. The contents of nitrogen, phosphorus, potassium and organic matter increased by 96.14%, 42.17%, 105.65% and 63.79%, respectively, under T1010 compared with those under CK. Under T1010, soil bacteria, actinomyce, fungi and azotobacters amounts increased by 170.95%, 82.68%, 152.17% and 471.93%, respectively, compared with those under CK. Beneficial properties to plants growth (e.g., soil compaction, ≥0.25 mm water stable aggregate, organic matter, microbial amount) of moderately saline coastal platform soils with Trichoderma agent (T1010) increased, respectively, by 1.53, 2.11, 3.20 and 28.33 times over that of flood land in coastal saline area. On the contrary, harmful property to plants growth, water soluble salts, reduced by 96.60%. Properties (such as soil compaction, porosity, moisture, contents of phosphorus and organic matter, and microbial amounts) of Trichoderma-amending moderately saline coastal soils were not significantly different from that of slightly saline coastal alkali soils. Reduced bulk density or increased porosity of moderately coastal saline platform fields with Trichoderma were close to that of the non-saline solar-greenhouse soils. Application of microbiological agents effectively improved soil properties of moderately saline coastal platform fields and ameliorated the ecological environment by enhancing soil aggregate structure, increasing soil nutrient and beneficial microorganisms amount.