生物炭、河沙对盐碱土水盐、氮素及玉米产量 的 影响

Amending Saline-Alkali Soils with Biochar or Fluvial Sand to Improve Bioavailable Nitrogen and Yield of Summer Maize

【目的】探究连续施用生物炭与河沙1 a和3 a对黄河三角洲地区中度盐碱土的改良效果、氮素及夏玉米产量的影响。【方法】采用田间小区试验,共设置CK、C1[5 t/(hm^(2)·a)生物炭]、C2[10 t/(hm^(2)·a)生物炭]、C3[20 t/(hm^(2)·a)生物炭]、S1(5%沙)、S2(10%沙)、S3(15%沙)7个处理。【结果】①施加生物炭对掺炭层土壤含水率提升效果显著,施用1 a较CK增加2.20%~7.34%,第3年较CK增加5.08%~16.38%。其中,C3处理效果较优;随施沙量增加,掺沙层的土壤含水率呈降低趋势。②3 a累积效应下,掺沙处理土壤降盐效果要优于生物炭处理,掺沙10%~15%的脱盐效果较好,较CK脱盐率达15.52%,且3 a累积效果优于1 a。③施加生物炭能明显提高0~40 cm土层的硝态氮(第1年:10.34%~60.60%;第3年:14.24%~41.92%)、铵态氮量(第1年:0.96%~16.96%;第3年:-4.56%~7.37%),其中,C3处理增幅显著,掺沙处理则仅提升了20~40 cm土层氮素量。④生物炭处理对夏玉米产量的提升优于掺沙处理,第3年较第1年增幅为2.40%~19.86%,且随施炭量增加而增大。【结论】添加生物炭对盐碱地的改良效果、氮素量及作物产量的提升要优于掺沙,且3 a的累积效果较优,因此,建议对黄河三角洲地区的中度盐碱地长期掺加20 t/(hm^(2)·a)的生物炭。

【Objective】Soil salinity and alkalinity is a common abiotic stress affecting crop growth worldwide.The objective of this paper is to investigate the efficacy of amending the soil with biochar or fluvial sand to improve nitrogen bioavailability and yield of summer maize.【Method】A three-year plot experiment was conducted at a field in the Yellow River delta.There were three biochar treatments:5 t/(hm^(2)·a)(C1),10 t/(hm^(2)·a)(C2),20 t/(hm^(2)·a)(C3),and three sand amendment treatments(w/w):5%(S1),10%(S2)and 15%(S3);the control(CK)was no amendment.In each treatment,we measured the changes in soil water content,soil salinity,nitrate and ammonium,as well as the final maize yield.【Result】①Amending the soil with biochar,especially C3,was more effective than with sand to improve the 0~20 cm soil water content;compared with CK,it increased the soil content by 2.20%~7.34%in the first year and 5.08%~16.38%in the third year.②Amendment with sand,especially S2 and S3,was more effective than with biochar to desalinize the soils;compared with CK,it increased soil desalination by up to 15.52%three years after the amendment.③Compared with CK,amendment with biochar increased nitrate content in 0~40 cm soil by 10.34%~60.60%in the first year and 14.24%~41.92%in the third year,while in the meantime increased ammonium content by 0.96%~16.96%and-4.56%~7.37%in the first and third year respectively.Overall,C3 was most effective in improving mineral nitrogen content.In contrast,amendment with sand increased mineral nitrogen in 20~40 cm soil but at the expense of mineral nitrogen in the top 0~20 cm soil.④Amendment with biochar was more effective in improving maize yield,with the yield in the third year increasing by 2.40%~19.86%compared with that in the first year.It was found that the yield increase was proportional to the biochar application.【Conclusion】Amending the saline-alkali soil with biochar improved mineral nitrogen and its bioavailability to crop,and the improvement increased as time elapsed.For the experiments conducted at the field in the Yellow River delta,the most effective amendment was adding 20 t/(hm^(2)·a)of biochar to the soil.