田菁改良重度盐渍化土壤的效果分析

为评价田菁改良重度盐渍化土壤的效果，试验设置4个处理：（1）只种植田菁(T)；（2）种植田菁，施用二铵450 kg/hm²(TA)；（3）种植田菁，施用磷石膏2250 kg/hm²(TG)；（4）不种植田菁的空白处理作对照(CK)。结果表明：施用磷石膏能够显著促进田菁生长(P<0.05)，TG处理地上部、地下部生物量较T、TA处理分别增加了14.24%、24.77%和8.32%、12.39%，施用二铵对田菁生长的促进作用不显著。种植田菁能够显著降低重度盐渍化土壤含盐量、容重，提高土壤速效氮、速效钾、水溶性有机质(DOC)含量，及土壤大团聚体含量、平均重量直径(MWD)、总孔隙度(P<0.05)，TG处理改良效果最大。相关分析表明，盐渍化土壤含盐量、Na⁺含量、DOC、有机质是维系盐渍化土壤结构的关键性状，降低土壤含盐量、Na⁺含量，提高DOC、有机质含量是盐渍化土壤改良方向。种植田菁，同时施用磷石膏是一种快速提升重度盐渍化土壤肥力的有效方法。

Effect of Sesbania cannabina Cultivation on Severe Salinity Soil Fertility Improvement

In order to study the effect of Sesbania cannabina cultivation on severe salinity soil fertility improvement, four treatments were designed: (1) Sesbania cannabina cultivation (T); (2) Sesbania cannabina cultivation and diammonium phosphate applied at the rate of 450 kg/hm² (TA); (3) Sesbania cannabina cultivation and phosphogypsum applied at the rate of 2250 kg/hm² (TG); (4) without Sesbania cannabina cultivation (CK). The results showed that phosphogypsum application could significantly promote the growth of Sesbania cannabina (P<0.05). Compared with that of T and TA treatment, the biomass of the aboveground part and underground part of TG treatment increased 14.24%, 24.77% and 8.32%, 12.39%, respectively, and the improving effect of diammonium phosphate application on Sesbania cannabina cultivation was not significant. Sesbania cannabina cultivation could significantly decrease soil salt content, bulk density, and significantly increase available nitrogen, available potassium, dissolved organic C (DOC), macro-aggregate content, mean weight diameter (MWD) and total porosity (P<0.05), the improving effect of TG was the best. The correlation analysis showed that soil salinity, Na concentration, DOC and organic matter content played an important role in the regulation of salinity soil structure. The improving methods included decreasing soil salinity and Na concentration, and increasing DOC and organic matter content. Sesbania cannabina cultivation with phosphogypsum application was an efficient method to improve the fertility of severe salinity soil.