Comparative Study On The Field Capacity Based On Different Test Methods

Soil field capacity is an important index of soil holding water capacity,and it is the important index of analysing and evaluating soil moisture and drought evaluation.The methods of testing the field capacity are generally divided into field measurement and indoor test.The field measurement method includes natural precipitation method,coaming flood irrigation method,etc.The indoor experimental measurement includes sandbox method,ring cutting method(agriculture),etc.Due to the uniqueness of soil samples(the soil texture may be different although they are from the same sample),so the field capacity is not constant,and the measured results vary because of the different test conditions and drainage time.The results may be different when adopting different methods of testing the field capacity and the results will be influenced by some factors,such as experimental methods,seasons,drainage time,testing conditions.This time we choose three kinds of typical areas in the central and western regions of Jilin province as the research area in order to carry out the comparative study on the field capacity.We use coaming flood irrigation,sand box and ring cutting method(agricultural)to measure the field capacity.After analyzing the data,we put forward different capacity testing methods which are suitable to different fields,different methods to test the field capacity,and also study the changes of the field capacity in different seasons.By simplifying steps as much as possible,confirming the testing time and frequency to improve the efficiency and the precision of field capacity measurement,thus provide technical support for soil moisture and drought evaluation analysis,and provide important research on the rules of different soil texture.The main results are as follows:1.The coaming flood irrigation method is suitable for different soil texture field capacity measurement,and testing environment is consistent with the field fact,the results are reasonable.2.The data are higher on the whole when using sand box method,the sampling time of loam and clay station can be extended appropriately according to the actual situation of the experimental sites,the results should be combined with local actual moisture evaluation application reference.3.Ring cutting method(agricultural)determination of sand station are comparatively consistent with the round box flood irrigation method,which can be used to test the field capacity.4.The results of the field capacity are similar in the same testing area in different seasons,so the field capacity is not affected by season.5.The time node of different soil texture field capacity is different.