微生物改良基质对新围垦海涂盐土改良的初步研究

海涂围垦区是陆海过渡带,围垦区土壤的传统洗盐和培肥技术易威胁近海生态环境,因此,探索新型、生态的盐土改良技术十分重要。该研究初步研究了新型微生物改良基质的盐土改良功能,结果表明微生物改良基质效果显著。相较于对照处理,微生物改良基质处理水稻产量增加了83.2%(P<0.05);土壤饱和含水率、田间持水量、总孔隙度、有机质、全氮、速效钾分别增加了13.80%、20.00%、6.80%、2.30倍、53.00%、31.00%(P<0.05);土壤容重降低了6.90%;土壤细菌、真菌和放线菌数量分别增加了10.30、11.20和3.18倍;水稻生育期累积灌溉水量减少了35.20%;0~10和>10~20cm土层可溶性盐质量分数分别降低了61.10%和54.40%。微生物改良基质能够在短期内加速盐分洗脱,提升土壤质量,是海涂新围垦区盐土改良的生态高效措施。

Preliminary study on the effect of microbial amendment on saline soils in a coastal reclaimed area

In a land-sea transitional zone, various technologies are used to reduce the accumulation of water-soluble salts for the efficient utilization of saline soils in coastal reclaimed areas. In the conventional processes of salt-washing and fertilizing, the emission of the agricultural non-point pollutants has posed a threat to the offshore ecological environment. Therefore, it is necessary to explore new environmentally friendly methods for the improvement of soils quality. In microbial amendments, soils was fermented by adding Bacillus amyloliquefaciens IAE (7.2×1010 cfu/g) in the matrix at percentage of 1% (w:w), while the substrate was prepared in the combination of Flammulina velutipes residues, scoria of bentonite, vinegar production residues and humus acid, at the ratio of 6:2:1:1 (w:w). The matrix that fermented without the inoculation of B. amyloliquefaciens IAE, generally named as soil amendment. To investigate the effect of the soil amendment and microbial soil amendment on coastal reclaimed saline soils, three treatments were set in this study: 1) control, soil without any treatment; 2) soil amendment treatment (SAT), soil added with soil amendment at 30 t·ha-1; 3) microbial soil amendment treatment (MSAT), soil added with microbial soil amendment at 30 t·ha-1. The pilot field was located at Tiaozini coastal reclamation area in Dongtai, Jiangsu Province, China. The contents of soluble salt in soils were ranged from 3.57 to 10.66 g/kg. Water saving irrigation and traditional paddy planting methods were also selected in three treatments. The quantified data have been recorded including the irrigation quantity, biological characteristics of paddy, physical and chemical features and microbial properties of the soils. The results showed that both SAT and MSAT improved paddy soil properties, and MSAT did better than that. Compared to those in the control treatment, the accumulative irrigation quantity in MSAT decreased by 35.2% (P<0.05), while the plant height, number of grains per ear, thousand grains weight, effective ear yield, and rice yield in the MSAT treatment increased by 31.4%, 30.3%, 29.7%, 17.5%, and 83.2%, respectively. The contents of saturation moisture, water holding capacity, total porosity, capillary porosity, organic matter content, total nitrogen content, and content of available potassium in soils in MSAT increased by 13.8%, 20.0%, 6.80%, 9.79%, 2.30 times, 53.0%, 31.0%, respectively, compared to those in the control treatment. Populations of the soil microorganisms of bacteria, fungi and actinomyces in MSAT increased by 10.3, 11.2 and 3.18 times, respectively (P<0.05). Meanwhile, the bulk density of soils in MSAT decreased by 6.90% (P<0.05), compared to that in the control treatment. The contents of soluble salts in the soil depth of 0-60 cm in MSAT were significantly lower than those in control treatment, and those in tillage layer of 0-10cm and 10-20cm decreased by 61.1% and 54.4%, respectively. This finding demonstrates that microbial amendment can contribute to physical structure and microbial properties of soils, thereby to increase in the water conductivity while decrease in salt content in soils. This study can also provide a promising and feasible method to improve the quality of saline soils in coastal reclaimed zone.