Abstract
The comprehensive and reliable perception of moisture in a soil profile is essential to irrigation. To establish an efficient method for sensing soil moisture, field trials were conducted to analyze the spatial and temporal variations of moisture in a paddy soil profile by using coefficients of variation. The results showed that soil layers at shallow depths undergo more extensive changes in the coefficients of variation. Moisture perception is most sensitive within a depth range of 0-60 cm in the vertical soil profile of a paddy field. By using the clustering algorithm of Euclidean distance, the paddy soil profile was divided into three categories based on soil depth. The first category includes depths ranging from 10-20 cm, the second is from 30-40 cm, and the third is from 50-100 cm. Path analysis indicated that the most sensitive depths for moisture sensing in a paddy soil profile were 20 cm, 30 cm, and 50 cm, whereas the most sensitive depths for moisture sensing by time stability analysis were 20 cm, 40 cm, and 60 cm. Based on the multiple regression of sensitive depths, the results of quantitative inversion indicated that the time stability analysis results were 0.962 when the of path analysis was 0.980, and the time stability analysis was 0.61 when the root mean square error (RMSE) of path analysis was 0.40. The relative error range between the measured and predicted values of path analysis was less than that of time stability analysis. These findings suggest that it is feasible to effectively sense the moisture of the entire vertical soil profile based on the sensitive depth. The present study has also determined that path analysis is superior to time stability analysis. Keywords: paddy field, profile soil, moisture perception, clustering algorithm, path analysis DOI: 10.25165/j.ijabe.20181104.3593 Citation: Gao Z R, Ni J, Zhu Y, Jiang Q, Cao W X. Water-efficient sensing method for soil profiling in the paddy field. Int J Agric & Biol Eng, 2018; 11(4): 207-216.
Highlights
Soil moisture has obvious temporal and spatial variability and is one of the main factors affecting crop growth and yield
The investigation on the spatiotemporal variability in soil moisture in the paddy field showed that the key areas of soil moisture perception in a vertical profile in the paddy field are within the depth range of 0-60 cm
The moisture perception area of the paddy soil profile was determined to range from the 0-60 cm depth
Summary
Soil moisture has obvious temporal and spatial variability and is one of the main factors affecting crop growth and yield. Real-time and comprehensive soil moisture perception require a large number of soil moisture sensors in different soil layers, which results in tedious measurements, large signal interference, and high cost. The establishment of a novel, low-cost, high-performance moisture perception method for soil profiling to improve irrigation efficiency is a significant advancement in the agricultural industry. There is demand for a method for paddy fields that provides appropriate irrigation and water supply, these two factors affect the rate of water cycling and migration in paddy rice, and directly or indirectly affect its growth, physiology, and yield[3]. The persistence of water supply and the intermittence of irrigation or rainfall result in large variability of soil moisture in the paddy field. Methods for moisture perception of paddy soil profiles are limited, and the depth of the sensitive soil layer can only be determined by experience[8,9,10]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
