不同氮肥配施生物炭对镉污染土壤青菜镉吸收的影响

氮是作物生长的必需营养元素，生物炭是一种良好的土壤修复材料.以镉(Cd)污染农田土壤为对象，采用青菜盆栽试验研究尿素、硫酸铵和硝酸钙这3种氮肥配施生物炭对青菜生长和Cd吸收的影响.结果表明，施用氮肥和生物炭促进了青菜生长，与不施氮肥的对照处理相比，单施尿素、硫酸铵、硝酸钙和生物炭处理青菜生物量显著增加了5.02%～32.9%,不同氮肥配施生物炭处理青菜生物量比单施氮肥处理显著增加了8.84%～50.8%.单施尿素后土壤pH值比对照处理显著降低了0.27个单位，土壤有效态Cd含量显著增加了30.0%.单施硫酸铵后土壤pH值比对照处理显著降低了0.33个单位，青菜Cd含量显著增加了29.2%.单施硝酸钙对土壤pH值和青菜Cd含量无显著影响，而单施生物炭后土壤pH值比对照处理显著提高了0.35个单位，土壤有效态Cd含量和青菜Cd含量分别显著降低了57.4%和53.7%.氮肥配施生物炭处理土壤pH值比单施氮肥处理显著提高了0.14～0.28个单位，土壤有效态Cd含量和青菜Cd含量分别显著降低了16.5%～30.1%和15.3%～28.6%.总体来看，配施生物炭能够调节不同氮肥对污染土壤中Cd有...

Effects of Combined Application of Different Nitrogen Fertilizers and Biochar on Cadmium Uptake by Pakchoi (Brassica chinensis L.) in Cadmium Contaminated Soil

Nitrogen is an essential nutrient element for crop growth, and biochar is a good material for soil remediation. In this study, a pakchoi (Brassica chinensis L.) pot experiment was conducted to investigate the effects of the combined application of three nitrogen fertilizers, including urea, ammonium sulfate, calcium nitrate, and biochar on pakchoi growth and cadmium (Cd) uptake from cropland soil contaminated by Cd. The results showed that the application of nitrogen fertilizers and biochar prompted pakchoi growth, and the biomass of pakchoi in the treatments of single applications of urea, ammonium sulfate, calcium nitrate, and biochar were significantly increased by 5.02%-32.9%, as compared with that in the control treatment without nitrogen fertilizer application. The biomass of pakchoi in the treatments of the combined application of nitrogen fertilizers and biochar were significantly increased by 8.84%-50.8%, as compared with that in the treatment of the single application of nitrogen fertilizer. Compared with that under the control treatment without nitrogen fertilizer application, the single application of urea significantly reduced soil pH by 0.27 and significantly increased the content of soil available Cd by 30.0%. The single application of ammonium sulfate significantly reduced soil pH by 0.33 and significantly increased Cd content in pakchoi by 29.2%, as compared with that in the control treatment. The single application of calcium nitrate had no significant effect on soil pH or Cd content in pakchoi, whereas the single application of biochar significantly increased soil pH by 0.35 and significantly decreased the content of soil available Cd and content of Cd in pakchoi by 57.4% and 53.7%, respectively, as compared with that in the control treatment. Soil pH in the treatments of the combined application of nitrogen fertilizers and biochar was significantly increased by 0.14-0.28, the contents of soil available Cd were decreased by 16.5%-30.1%, and the contents of Cd in pakchoi were reduced by 15.3%-28.6%, as compared with that in the treatment of single application of nitrogen fertilizers. In general, the application of biochar could adjust the effects of different nitrogen fertilizers on Cd availability in the contaminated soil. During the remediation process of heavy metal-contaminated cropland, nitrogen fertilizer should be selected and applied reasonably to obtain the maximum economic and environmental benefits.