生物炭、有机肥连续施用对盐碱土壤改良效果研究

Effect of continuous application of biochar and organic fertilizers on saline-alkali soil improvement

为探究生物炭和有机肥连续施用3 a对黄河三角洲地区中度盐碱土改良效果及对水溶性盐基离子时空变化规律的影响,采取田间小区试验,共设置CK(仅施N 550 kg·hm^(-2)·a^(-1),P_(2)O_(5)120 kg·hm^(-2)·a^(-1))、C1(5 t·hm^(-2)·a^(-1)生物炭)、C2(10 t·hm^(-2)·a^(-1)生物炭)、C3(20 t·hm^(-2)·a^(-1)生物炭)、N1(7.5 t·hm^(-2)·a^(-1)有机肥)、N2(10 t·hm^(-2)·a^(-1)有机肥)6个处理。结果表明:(1)生物炭对0~20 cm土层土壤含水率提升效果优于有机肥,C3处理增幅最大,C2处理略小于C3,较CK增幅达17.98%;20~40 cm土层,各处理土壤含水率呈下降趋势(降幅4.39%~9.23%);土壤含水率变异程度表征C2处理具有更稳定的保水性能。(2)生物炭处理明显降低了各层土壤含盐量(降幅3.56%~9.80%),C2处理较CK降幅达9.80%,有机肥处理降盐效果欠佳。(3)在0~40 cm土层中,各处理表现出降低Na+含量(降幅4.59%~12.51%)、钠吸附比(SAR降幅12.67%~23.61%)及碱化度(ESP,降幅16.05%~30.06%)的效果,其中生物炭处理对Na^(+)的降低效果优于有机肥,C2处理较优,有效地抑制了Na+的毒害,但对Ca^(2+)、Mg^(2+)含量提升及SAR、ESP值降低的效果略差于有机肥。(4)生物炭对小麦增产效果优于有机肥,且C2处理效果最优,增产率达20.97%。综上所述,生物炭在提高土壤持水能力、作物产量和盐碱地综合改良方面优于有机肥,且C2处理较优。因此,黄河三角洲地区的中度盐碱土采用10 t·hm^(-2)·a^(-1)的生物炭施用量进行改良较为适宜。

A contrast analysis of biochar and organic fertilizer on the improvement of saline-alkali soil and the spatial-temporal variation of basic ions in the Yellow River Delta was conducted under a field plot experiment with six treatments including CK(only fertilize with N 550 kg·hm^(^(-2))·a^(-1),P2O5120 kg·hm^(^(-2))·a^(-1)),C1(5 t·hm^(^(-2))·a^(-1) biochar),C2(10 t·hm^(^(-2))·a^(-1) biochar),C3(20 t·hm^(^(-2))·a^(-1) biochar),N1(7.5 t·hm^(^(-2))·a^(-1)organic fertilizer),and N2(10 t·hm^(^(-2))·a^(-1) organic fertilizer).The result showed:(1)The effect of biochar on soil moisture content improvement in 0~20 cm soil layer was better than the organic fertilizer,among them C3 increased the most while C2 was slightly less than C3,up to 17.98%.The soil moisture content of each treatment showed a decreasing trend in 20~40 cm soil layer,but the difference was not significant.The C2 treatment had the smallest variation range of soil moisture content and stable water held capacity.(2)Biochar was better than organic fertilizer in reducing soil salinity,reduced the soil salinity by 3.56%to 9.80%.The C2 treatment showed a significant decrease,up to 9.80%lower than CK did.(3)In the 0~40 cm soil layer,all treatments reduced Na+content by 4.59%to 12.51%and sodium adsorption ratio(SAR)by 12.67%to 23.61%,exchangeable sodium percentage(ESP)by 16.05%~30.06%.(4)Biochar was better than organic fertilizer in inhibiting the toxicity of Na^(+).The C2 treatment was better,but it was less effective than organic fertilizer in increasing Ca^(2+) and Mg^(2+) contents,reducing SAR and ESP.(4)Biochar had better effect on the yield growth than organic fertilizer did.The yield increase rate of C2 was 20.97%.Biochar was superior to organic fertilizer in improving soil water holding capacity,increased crop yield and comprehensive improvement of saline alkali land,and C2 treatment had a best effect.So,it is recommended to add 10 t·hm^(^(-2))·a^(-1) biochar to the saline-alkali soil in the Yellow River Delta for improvement.