调控措施对滨海盐渍土磷素形态及作物磷素吸收的影响

滨海盐渍化土壤存在磷素有效性低的问题。本试验采用根袋法盆栽试验,共设不施磷肥、常规磷肥、磷肥+生物质炭、磷肥+腐殖酸、磷肥+商品有机肥5个处理,分析不同调控措施对非盐渍土、轻度盐渍土和中度盐渍土有效磷含量、磷素形态以及大麦磷素吸收利用的影响。结果表明:①盐碱障碍降低根区内外土壤有效磷含量,表现为非盐渍土>轻度盐渍土>中度盐渍土。添加生物质炭能显著提高轻度、中度盐渍土根区内外土壤有效磷含量,较常规磷肥对照处理分别提高40.72%、84.80%。②盐碱障碍降低大麦产量,抑制地上部对磷素的吸收,不同调控措施均能促进盐渍土上大麦对磷素的吸收,提高磷肥利用率。轻度盐渍土上不同调控措施的增产效果不显著,中度盐渍土上添加生物质炭处理显著提高大麦产量,较常规磷肥对照处理提高63.20%。③盐碱障碍降低土壤活性无机磷、NaOH-Pi、NaHCO₃-Po、NaOH-Po比例,增加HCl-Pi比例。添加生物质炭处理能显著提高盐渍土活性无机磷比例,提高土壤磷的有效性。添加生物质炭和商品有机肥处理对中度盐渍土上HCl-Pi比例的降低效果优于轻度盐渍土。

Effects of Different Management on Phosphorus Fractions in Coastal Saline Soil and Phosphorus Absorption and Utilization by Crops

Low availability of phosphorus (P) universally occurs in coastal saline soil. A root-bag pot experiment was conducted, 5 treatments were designed: 1) CK0, no application of P; 2) CK, conventional P fertilizer; 3) FC, application of biochar; 4) FH, application of humic acid; 5) FM, application of organic and inorganic P. The effects of different treatments on the content of available P, P fractions and P absorption were investigated for non, light and moderate saline soils, respectively. The results showed that:1) Available P contents in rhizosphere and non-rhizosphere soils decreased with the increase of soil salinity. The addition of biochar significantly increased available P in light and moderate saline soils, which were 40.72% and 84.80% higher than those of CK, respectively. 2) The salinization obstruction decreased barley yield and P absorption by barley aboveground. All treatments promoted P uptake by barley in saline soil and improved the utilization rate of P fertilizer. The yield-increasing effect was not significant in light saline soil for all treatments, while FC treatment significantly increased barley yield by 63.20% in moderate saline soil than CK. 3) Salinization obstruction reduced the proportion of soil active inorganic P, NaOH-Pi, NaHCO₃-Po and NaOH-Po, but increased the proportion of HCl-Pi. In conclusion, FC treatment significantly increased the proportion of active inorganic P in saline soil, which improved the availability of soil phosphorus, and FC and FM treatments reduced HCl-Pi ratio more in moderate saline soil than in light saline soil.