摘要
摘要:为实现泥质滨海盐土低成本快速脱盐后种植经济作物，本研究以磷石膏、牛粪、腐殖酸和玉米秸秆为复合改良物料的原料，利用了"深翻耕、浅改良、高垄作、少滴灌"农艺措施和耐盐植物梯次种植的生物措施，采取L₁₆（4⁵）正交设计开展试验研究，系统分析了不同复合改良物料对泥质滨海重盐土的改土降盐和对经济作物黄蜀葵的增产效果；应用模糊数学评判原理与方法，综合评价了各复合改良物料的改土降盐与增产效应，确定出适合滨海泥质盐土应用的优选复合改良物料。结果表明：在"翻耕40 cm，改良30 cm，起垄15 cm，滴灌土壤基质势控制在-10 kPa，前茬种植田菁"的综合农艺措施条件下，本研究中物料成本在2.55~6.01元·m^-2的各复合改良物料对泥质滨海盐土均有显著的改土降盐效果，0~10 cm土层土壤盐分含量均由10.86 g·kg^-1下降到2.0 g·kg^-1以下，10~20 cm土层土壤盐分含量下降到2.5 g·kg^-1以下；0~10 cm土层土壤有机质增加到12 g·kg^-1以上，土壤碱解氮和有效磷含量提升明显，土壤大团聚体含量增加2.41~7.62倍。以土壤盐分含量、pH、有机质、碱解氮、有效磷、速效钾、微团聚体为评价指标，结合物料成本，筛选出适宜于滨海泥质重盐渍土的最优复合改良物料：22 500 kg·hm^-2磷石膏+105 m³·hm^-2有机肥+3 750 kg·hm^-2腐殖酸+45 m³·hm^-2玉米秸秆，该最优复合物料应用两年后，土壤有机质、碱解氮含量最高，与对照相比分别增加181.87%和130.52%，物料施用成本仅4.05元·m^-2。
关键词:滨海盐土/
复合改良物料/
农艺措施/
耐盐植物/
土壤含盐量/
土壤养分/
盐碱地改良
Abstract:The aim of this study was to develop a rapid, low-cost method to desalinate muddy coastal saline soil to facilitate its use for economic crops. We used composite improvers (phosphogypsum, dung, humic acid, and corn straw), comprehensive agronomic measures (deep tillage, shallow soil improvement, high ridge cultivation, and drip irrigation), biological measures (step planting of salt-tolerant plants), and adopted L₁₆(4⁵) orthogonal design, and fuzzy mathematic evaluation to systematically analyze the effects of composite improvers on soil amelioration, salt reduction, and Abelmoschus manihot (L.) Medic yield. The total effect of each composite improver was comprehensively evaluated, and the preferred improvers suitable for application on coastal muddy saline soil were determined. Results showed that composite improvers with a capital cost of 2.55-6.01 ￥·m^-2 significantly reduced soil salt content when used with comprehensive agronomic measures consisting of 40 cm of tillage, 30 cm of soil improvement, 15 cm of ridge, drip irrigation controlled to -10 kPa of soil potential, and Sesbania cannabina (Retz.) Poir used as the fore-rotating plant. Soil salt content decreased from 10.86 g·kg^-1 to < 2.0 g·kg^-1 in the 0-10 cm soil layer and to < 2.5 g·kg^-1 in 10-20 cm layer. Soil organic matter content increased to >12 g·kg^-1; there were significant increases in alkali-hydrolyzed nitrogen and available phosphorus, and the soil macroaggregate content was 2.41-7.62 times higher than that of the control. The proper combinations of composite improvers for heavy saline silt soil were screened based on the comprehensive evaluation of soil salt content, pH, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium, and micro-aggregates. A combination of 22 500 kg·hm^-2 phosphogypsum + 105 m³·hm^-2 organic fertilizer + 3 750 kg·hm^-2 humic acid + 45 m³·hm^-2 maize straw provided the optimum effect on the improvement of coastal saline soil. Soil organic matter and alkali-hydrolyzed nitrogen increased by 181.87% and 130.52%, respectively, whereas the capital cost was only 4.05 ￥·m^-2. Two other combinations provided suboptimal results:15 000 kg·hm^-2 phosphogypsum + 75 m³·hm^-2 organic fertilizer +3750 kg·hm^-2 humic acid +135 m³·hm^-2 maize straw (capital cost 4.48￥·m^-2); and 30000 kg·hm^-2 phosphogypsum +5 m³·hm^-2 organic fertilizer +2250 kg·hm^-2 humic acid +135 m³·hm^-2 maize straw (capital cost 5.02 ￥·m^-2).
Key words:Coastal saline soil/
Composite soil improvement agent/
Agronomic measure/
Salt tolerant plant/
Soil salinity/
Soil nutrient/
Saline land improvement



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