蛋白多肽对强酸化土壤的改良效应

以强酸化土壤(pH为4.30)为研究对象,以蛋白多肽为新型土壤改良剂,将传统施加生石灰的酸化土壤治理技术和施加复混肥的常规种植技术为对照,研究蛋白多肽对强酸化土壤的改良效应。结果表明:土培实验中的蛋白多肽与生石灰对强酸化土壤均有碱化效应,将土壤pH分别提高了0.23和0.30 (120 d稳定值),而复混肥碱化程度较低(提高0.02);同时,蛋白多肽组与生石灰组土壤交换性酸含量比复混肥组(35.93 mmol·kg-1)分别降低了12.56 mmol·kg-1和18.68 mmol·kg-1,盐基饱和度分别比复混肥组(67.30%)高7.01%和9.85%;蛋白多肽组土壤有机质含量(19.96 g·kg-1)变化尤为明显,并且,显著高于复混肥组(8.58 g·kg-1)和生石灰组(12.23 g·kg-1)。蛋白多肽与生石灰均能提高强酸化土壤pH,但未能一次性达到6.5以上的中性程度。基于此,以结球甘蓝为供试植物,研究此背景下的种植情况。结果显示,蛋白多肽可在偏低pH条件下种植出高产的结球甘蓝,比其他组合效果明显,其平均生物量(371.78 g)比复混肥组和生石灰组分别高9.54倍和1.90倍。蛋白多肽具有改良强酸化土壤的潜力,并能达到改良与种植同步化(蛋白多肽施加后直接种植作物幼苗)。研究结果可为强酸化土壤的改良与种植提供参考。

Decreased Soil Nitrification Rate with Addition of Biochar to Acid Soils

This study was conducted to investigate the effects of mixed biochar on the nitrification rate in acidic soils. A15 N tracer experiment with(15 NH4)2 SO4 was conducted to determine the nitrification rates of 4 acidic agricultural soils with p H 4.03-6.02 in Yunnan Province, Southern China. The accumulation of15 N-NO3-and nitrification rates decreased with the addition of biochar at the end of incubation, suggesting that biochar could be a nitrification inhibitor in acidic fertilized soil. Nitrification rates in soil with p H 4.03 were evidently lower than those in soil with p H 4.81-6.02 with or without biochar. Decreased nitrification rates were detected in the acidic soils with biochar. Soil p H controlled nitrification more than biochar in certain strongly acidic soils.