基于冠层叶-气温差的温室土壤水分诊断

根据对日光温室条件下番茄全生育期的冠层温度、气温、土壤水分以及一些相关气象因素测定,分析了冠层叶-气温差与土壤容积含水率、湿度之间的关系。结果表明:在日光温室条件下,番茄全生育期内冠层叶-气温差的日变化呈曲线分布,冠层叶-气温差的最高值出现在每天的13∶00～15∶00之间。通过对主要生育期13∶00～15∶00的数据分析发现,冠层叶-气温差(△T)与土壤容积含水率(SW)以及棚内湿度(RH)之间有较好的复相关关系,结合容积含水率与湿度对冠层叶-气温差的综合影响,可以得出△T与SW呈负相关关系,与RH呈正相关关系,相关系数R2为0.778。通过偏相关分析,冠层叶-气温差与容积含水率的相关性最大,呈负相关关系,相关系数R2为0.778,并通过数据验证,实测值(Y)与模拟值(X)相关性较好,相关系数R2为0.723。因此可通过监测13∶00～15∶00的冠层叶-气温差来了解作物的水分状况,为农田土壤水分诊断提供科学依据。

Diagnosis of soil moisture in greenhouse based on canopy leaf-air temperature difference

According to measured result of canopy temperature,air temperature,soil moisture and some relevant meteorological factors during tomato’s whole growth in sunlight greenhouse conditions,analysis was made respectively of the relationship between canopy leaf-air temperature difference and soil water content and relative humidity.The result showed that: In the sunlight greenhouse condition,there were some peaks in the diurnal curve of canopy leaf-air temperature difference from tomato’s seedling stage to fruiting period,and the maxmum of canopy leaf-air temperature difference’s value appeared during 13∶00~15∶00 each day.Accoding to the data at 13∶00~15∶00 in tomato’s main growth period,we found that there was a significantly good correlation among canopy leaf-air temperature difference(△T),water content(SW) and relative humidity(RH),combined with water content and relative humidity on the comprehensive influence of the △T.We can get a result which is the △T has a negative relationship with water content and has a positive with relative humidity,R2 is 0.778.By partial correlation analysis,we concluded that the SW was the most important factor which affected △T,which was a negative linear correlation equation,and the R2 is 0.778.After validated with the measured data,it was found that the measured SW(Y) was well correlated with the simulated one(X),and R2 is 0.723.Therefore,we could get scientific basis for diagnosis of farmland soil moisture from the water status data which was monitored from canopy leaf-air temperature difference at 13∶00~15∶00.