麦秸水热炭及其改良产物对水稻产量和稻田氨挥发排放的影响

水热炭的酸性特性及材料吸附性质为其稻田回用及氨挥发损失控制提供了可能.为实现农业废弃物的资源化利用和稻田环境损失控制，本研究以小麦秸秆为原材料，通过土柱模拟试验，考察了麦秸水热炭（WHC）及其水洗改良产物（W-WHC）对水稻产量和稻田氨挥发排放的影响.结果表明，麦秸水热炭及其改良产物稻田回用能够增加水稻产量，低量添加（0.5%）的增产效应高于高量添加（1.5%）处理.低量添加下，WHC和W-WHC处理的水稻产量分别较对照处理（CKU）增加17.16%和20.20%.结果同时表明，除W-WHC低量添加处理的氨挥发损失量与对照相当，水热炭及其改良产物添加均能够减少稻田氨挥发损失.其中，WHC低量添加和W-WHC高量添加处理的稻田氨挥发损失显著低于CKU处理，NH₃挥发累积排放量分别减少31.01%和17.40%.阶段氨挥发损失结果分析表明，水热炭添加对稻田氨挥发损失的控制效应主要集中在蘖肥期和穗肥期，水热炭添加后蘖肥期田面水氮素浓度的变化和穗肥期田面水pH的改变是秸秆水热炭添加后稻田氨挥发控制的主要驱动因素.结果说明，适宜用量下小麦秸秆碳化还田可以在提高作物产量的同时减少稻田氨挥发损失，是一种适于农业副产物资源化利用的良好方式.

Effects of Wheat Straw Hydrochar and Its Modified Product on Rice Yield and Ammonia Volatilization from Paddy Fields

Hydrochar can mitigate ammonia volatilization when applied in paddy fields due to its acidity and adsorption property. To realize the recycling of agricultural biowaste as well as the control of nutrient loss from paddy fields, a simulation soil-column experiment with wheat straw hydrochar (WHC) and water-washed hydrochar (W-WHC) was conducted to evaluate the performance of rice yield and ammonia volatilization from paddy fields. The results showed that WHC and W-WHC applied in paddy fields both increased the rice yield and the increased effect at low application rate (0.5%) was higher than that at high application rate (1.5%). In comparison with the control treatment (CKU), the rice yields achieved from low application rate treatments for WHC and W-WHC increased by 17.16% and 20.20% respectively. Except for the equal emission rate between W-WHC with low application rate and CKU treatments, hydrochar (WHC, W-WHC) addition reduced the ammonia volatilization from paddy fields when compared with the CKU. Among them, the ammonia volatilization levels from low-application WHC and high-application W-WHC treatments were significantly lower than that from the CKU treatment, reduced by 31.01% and 17.40%, respectively. Based on the analysis of ammonia volatilization during different fertilization stages, the control effect of hydrochar addition on ammonia volatilization was mainly benefited from tillering and panicle fertilizer stages. The change in the nitrogen concentration of surface water at the tillering fertilizer stage and in pH at the panicle fertilizer stage with the addition of hydrochar was the main driving factor for the reduction in ammonia volatilization. The results show that sufficient amounts of hydrochar derived from wheat straw application can increase crop yield while reducing ammonia volatilization from paddy fields. This method provides an effective route for recycling agricultural biowastes.