Modelling soil water dynamics and root water uptake for apple trees under water storage pit irrigation

Xianghong Guo,Xihuan Sun,Tao Lei,Qiqi He,Shaowen Zhang,Juanjuan Ma,Lijian Zheng

doi:10.25165/j.ijabe.20191205.4005

Abstract

Water storage pit irrigation is a new method suitable for apple trees. It comes with advantages such as water saving, water retention and drought resistance. A precise study of soil water movement and root water uptake is essential to analyse and show the advantages of the method. In this study, a mathematical model (WSPI-WR model) for 3D soil water movement and root water uptake under water storage pit irrigation was established based on soil water dynamics and soil moisture and root distributions. Moreover, this model also considers the soil evaporation, pit wall evaporation and water level variation in the pit. The finite element method was used to solve the model, and the law of mass conservation was used to analyse the water level variation. The model was validated by experimental data of the sap flow of apple trees and soil moisture in the orchard. Results showed that the WSPI-WR model is highly accurate in simulating the root water uptake and soil water distributions. The WSPI-WR model can be used to simulate root water uptake and soil water movement under water storage pit irrigation. The simulation showed that orchard soil water content and root water uptake rate centers on the storage pit with an ellipsoid distribution. The maximum distribution region of soil water and root water uptake rate was near the bottom of the pit. Distribution can reduce soil evaporation in the orchard and improve the soil water use efficiency in the middle-deep soil. Keywords: root water uptake, soil water dynamics, numerical simulation, water storage pit irrigation, apple tree DOI: 10.25165/j.ijabe.20191205.4005 Citation: Guo X H, Lei T, Sun X H, Ma J J, Zheng L J, Zhang S W, et al. Modelling soil water dynamics and root water uptake for apple trees under water storage pit irrigation. Int J Agric & Biol Eng, 2019; 12(5): 126–134.

Highlights

Soil water movement and root water uptake are the key processes of the substance transport and energy transfer in farmland[1,2,3]
The results showed that the water movement model built in this study performed well in simulating the soil water dynamics under water storage pit irrigation. 3.4 Root water uptake distribution simulated by the WSPI-WR model under different pit depths
A mathematical model (WSPI-WR model) for a 3D soil water movement and root water uptake under water storage pit irrigation was established based on soil water dynamics, and soil evaporation, pit wall evaporation and water level variation in the pit had been considered

Summary

Introduction

Soil water movement and root water uptake are the key processes of the substance transport and energy transfer in farmland[1,2,3]. A quantitative study of soil water and root is the basis of formulating irrigation system and improving water use efficiency. Soil moisture is the main factor that restricts root water uptake[4,5,6]. A reasonable distribution of soil moisture in the root zone can promote root water uptake and improve water use efficiency. Water storage pit irrigation is a new method for simultaneously solving the problems of drought and soil erosion. During water storage pit irrigation, the soil infiltration interface changes. The distribution of soil moisture under water storage pit irrigation can reduce ground evaporation between plants, boost the growth of roots in middle-deep soil, change the distribution of root system and promote the root water uptake[11,12,13,14]

Objectives

Methods

Results

Conclusion