The National Key Research and Development Program of China(2017YFD0200106)
日光温室氮素投入量高，氨挥发损失是值得关注的问题之一。但目前对温室系统氨挥发排放测定多以土面氨挥发为主，而日光温室是一种半封闭式种植系统，由土面挥发出的部分NH3会被植物冠层吸收或溶解于棚膜水中回流于土壤，因此土面氨挥发难以准确反映日光温室排放到大气中氨的量，从而难以准确估计日光温室栽培系统NH3的实际排放量。为此，采用间歇式密闭室通气法连续测定了三季作物（番茄、西瓜、番茄）生长期间不同施肥处理（包括：不施氮+常规灌溉（N0+FI）、常规施氮+常规灌溉（FT+FI）、优化施氮+常规灌溉（OPT+OI）及优化施氮+优化灌溉（OPT+OI）4个处理）土面氨挥发损失量；同时连续两季采用风量罩测定通风口处气体流量，采用抽气法对通风口处氨浓度进行连续监测，以估算监测整棚（通风口处）氨挥发损失速率及损失量。结果表明，温室施肥后当天土面氨挥发速率出现峰值，7 d后施肥与未施肥对照无显著差异，三季种植期间各施氮处理其氨挥发排放量分别为N 2.82～4.97、6.59～9.97和15.77～21.83 kg·hm–2，相应的氨挥发系数分别为0.64%～1.50%、3.11%～4.21%和2.59%～3.90%；整棚氨挥发速率趋势与土面氨挥发基本一致，整棚氨挥发量第二季及第三季分别为N 2.22、2.92 kg·hm–2，仅占土面表氨挥发的13.38%～33.69%，氨挥发系数仅为0.46%～1.48%，显著低于土面氨挥发量。可见若以土面氨挥发来估算日光温室氨挥发会显著高估了我国日光温室系统氨挥发损失量，建议采用整棚观测的方法估算日光温室体系氨排放损失。
[Objective] Ammonia volatilization from solar greenhouses driven by excessive nitrogen input has received widespread attention in recent years. However, the ammonia volatilization emission of greenhouse system is mainly determined by soil surface ammonia volatilization. Greenhouses are semi-closed structures, as a result, a part of NH3 emitted from soil can be absorbed again by the plant canopy or dissolved in the greenhouse membrane water and returned to the soil. The volatilization of ammonia from soil surface can not accurately reflect the amount of ammonia discharged into the atmosphere by solar greenhouse. Therefore, ammonia volatilization from soil surface is difficult to accurately reflect the amount of ammonia emitted into the atmosphere by solar greenhouse.[Method] Experiment comprised four treatments:(i) no nitrogen input with conventional irrigation (N0+FI), (ii) conventional nitrogen input with conventional irrigation (FT+FI), (iii) optimum nitrogen input with conventional irrigation (OPT+FI), and (iv) optimum nitrogen input with optimum irrigation (OPT+OI). Ammonia volatilization losses were measured in three vegetables seasons (tomato-watermelon-tomato) using intermittent closed chamber ventilation method. The air volume mask (Kanomax 6570) was used to measure the gas flow at the vent, and the ammonia concentration at the vent was continuously monitored by pumping method. In this way, the loss rate and amount of ammonia volatilization were measured from the whole greenhouse, and losses were compared with the soil surface.[Result] The results showed that the ammonia volatilization rate peaked on the same day after greenhouse fertilization, and there was no significant difference between fertilized and unfertilized (control) after 7 days. During the three planting seasons, the ammonia volatilization under different nitrogen treatments were:2.82-4.97 kg·hm–2, 6.59-9.97 kg·hm–2and 15.77-21.83·kg hm–2, respectively, and the corresponding ammonia volatilization emission factors were 0.64%-1.50%, 3.11%-4.21% and 2.59%-3.90%, respectively. The trend of ammonia volatilization rate of the whole shed was basically consistent with that of the soil surface. The ammonia volatilization rate of the whole shed was N 2.22 kg·hm–2 in the second quarter and N 2.92 kg·hm–2 in the third quarter, which accounted for 13.38%-33.69% of the ammonia volatilization from the soil surface, and the ammonia volatilization coefficient was only 0.46%-1.48%, which was much lower than the ammonia volatilization from the soil surface.[Conclusion] Thus, it is concluded that the ammonia volatilization from solar greenhouse will be overestimated when only taking the soil surface ammonia volatilization into consideration. Measuring ammonia volatilization based on the whole solar greenhouse system is thus recommended in future studies.
张兆北,罗伟,白新禄,程于真,陈竹君,周建斌.日光温室栽培下土面及整棚氨挥发比较[J].土壤学报,2022,59(4):1068-1077. DOI:10.11766/trxb202101280056 ZHANG Zhaobei, LUO Wei, BAI Xinlu, CHENG Yuzhen, CHEN Zhujun, ZHOU Jianbin. Comparative Study on Ammonia Volatilization from Soil Surface and Whole Shed in Solar Greenhouse[J]. Acta Pedologica Sinica,2022,59(4):1068-1077.复制