鼠李糖脂改性生物炭对盐渍土小白菜抗性及氮素吸收的影响

为探究鼠李糖脂改性生物炭对盐渍土的改良效果，通过小白菜盆栽试验，以盐渍土壤为材料，按照占土壤质量1%和2%比例各添加4种浓度的鼠李糖脂改性生物炭（浓度为250 mg·L^-1的鼠李糖脂体积(V)占生物炭质量(m)比分别为15%、10%、5%、0%），研究了鼠李糖脂改性生物炭对盐渍土性质、氮素养分吸收以及小白菜生长和酶活性的影响。结果表明，与对照相比，鼠李糖脂改性生物炭提高了土壤有机碳含量和土壤铵态氮、硝态氮含量，但对土壤pH值无显著影响，其中，施加鼠李糖脂改性生物炭的处理与对照相比有机碳含量显著增加了55.05%~142.67%，施加鼠李糖脂改性生物炭比例为10%的处理平均与对照相比铵态氮含量显著提高了156.69%，施加鼠李糖脂改性生物炭比例为15%、10%的处理与对照相比硝态氮含量平均分别显著增加了37.94%、41.46%。施用鼠李糖脂改性生物炭显著增加了小白菜生物量和吸氮量，其中，改性比例为10%的处理平均分别比单施生物炭的处理增加了47.13%和43.64%。施用鼠李糖脂改性生物炭提高了叶片谷氨酰胺合成酶和过氧化物酶的活性，提高了可溶性蛋白含量，降低了丙二醛含量，其中，施加鼠李糖脂改性生物炭比例为10%的处理平均与对照相比叶片谷氨酰胺酶活性显著提高了113.64%、过氧化物酶活性显著提高了30.87%，施加鼠李糖脂改性生物炭比例为10%和5%的处理平均分别与对照相比可溶性蛋白含量提高了7.59%和37.60%，施加鼠李糖脂改性生物炭比例为10%的处理平均与对照相比丙二醛含量显著降低了80.60%。总体看来，采用鼠李糖脂改性的生物炭可以提高盐渍土小白菜的抗性，促进其对氮素的吸收，且以改性比例为10%效果最佳。

Effects of rhamnolipid modified biochar on resistance and nitrogen absorption of Chinese cabbage in saline soil

To explore the effects of rhamnolipid modified biochar on saline soil, a pot experiment of Chinese cabbage was set up. Four different treatments of rhamnolipid modified biochar (rhamnolipid volume (V) with concentration of 250 mg·L^-1 accounts for 15%, 10%, 5% and 0%) were added to saline soil according to the proportion of 1% and 2% to soil mass. The effects of rhamnolipid modified biochar on the properties of saline soil, nitrogen nutrient absorption, growth and enzyme activity of Chinese cabbage were studied. The results showed that compared with the control, rhamnolipid modified biochar increased the content of soil organic carbon, ammonium nitrogen and nitrate nitrogen, but had no significant effect on soil pH. Among them, the content of organic carbon in the treatment with rhamnolipid modified biochar was significantly increased by 55.05%~142.67% compared with the control, and the content of ammonium nitrogen in the treatment with rhamnolipid modified biochar of 10% was significantly increased by 156.69% compared with the control. Compared with the control, the content of nitrate nitrogen increased significantly by 37.94% and 41.46% in the treatment with 15% and 10% of rhamnolipid modified biochar. The biomass and nitrogen uptake of Chinese cabbage were significantly increased. The treatment with 10% modified ratio increased by 47.13% and 43.64% respectively compared with the treatment with biochar alone. The activity of glutamine synthetase and peroxidase in leaves were increased, the content of soluble protein was increased, and the content of malondialdehyde was reduced. The best effect was from the 10% modification ratio since the treatment significantly increased the activities of glutamine synthetase and peroxidase by 113.64% and 30.87% respectively compared with the control, and the soluble protein content of 10% and 5% treatment was increased by 7.59% and 37.60% respectively. The malondialdehyde content for the 10% treatment with rhamnolipid modified biochar was significantly reduced by 80.60% compared with the control. In general, the biochar modified by rhamnolipid improved the resistance of Chinese cabbage in saline soil and promoted its absorption of nitrogen, and the modified ratio of 10% was the best.