温室表层土壤硝态氮运移的水、热耦合效应研究

为了探讨温室作物生产水肥管理和温度环境对土壤NO3--N向表层迁移的影响,选用5 a的温室土壤样品进行土柱蒸发模拟试验,研究蒸发温度、土壤初始含水量、初始NO3--N含量及其耦合效应对温室土壤迁移速率及其垂直剖面分布的影响。试验结果表明:蒸发温度和土壤初始含水量明显影响NO3--N向土壤表层的迁移,并随蒸发温度和土壤初始含水量的增加而加强;通过正交回归分析得出影响NO3--N迁移速率的因素依次为初始含水量、蒸发温度以及温度与含水量的交互作用;土壤初始NO3--N含量以及它与蒸发温度、土壤初始含水量的交互作用对NO3--N迁移速率的影响不显著,但它影响土壤中各层的NO3--N绝对含量;经过5 d蒸发后,NO3--N沿垂直剖面分布出现上高下低,并出现一小的回升后逐渐趋于稳定。本文建立了蒸发条件下NO3--N迁移速率的回归模型,利用该回归模型,可为温室土壤在不同环境及水肥条件下NO3--N向表层迁移速率的预测提供依据。

Effects of Moisture and Temperature on NO3- -N Transport in Greenhouse Soil under Steady Vaporization

In order to investigate the effect of soil water,fertilizer and temperature management on the NO-3-N transport of soil in greenhouse crop production,a simulation experiment using the soil columns was inducted to determined the changes of NO-3-N transport rate and its gradients in soil vertical profiles under various vaporization temperature,initial soil moisture and NO-3-N contents for a 5 year greenhouse soil sample.The results showed that vaporization temperature and initial soil moisture had an influence effected significantly NO-3-N transport to top soils,and the transport rate increased with the increase of vaporization temperature and initial soil moisture.The effects on NO-3-N transport rat were a descending order of initial soil moisture,vaporization temperature,and their interaction.The effects of initial NO-3-N contents in soil and its interactions with vaporization temperature and initial soil moisture on NO-3-N transport rate were not significant,but it effected the absolute NO-3-N contents of soils.After water was evaporated in soil for 5days,it showed that NO-3-N content was higher in top layer soil and decreased with increase of soil depth,rose a little again and tended to a approximate steady value.A model for NO-3-N transport rate was determined under steady vaporization.This model can be used to predict NO-3-N transport rate to top soil for greenhouse under the different fertilizer and soil environment.