Soil Water Content and Temperature Dynamics under Grassland Degradation: A Multi-Depth Continuous Measurement from the Agricultural Pastoral Ecotone in Northwest China

Abstract

The agricultural pastoral ecotone (APE) in Northwest China is an ecological transition zone in the arid area with a very fragile ecosystem. In recent years, the ecosystem has deteriorated sharply, and increasing desertification has made the regional ecosystem more vulnerable and sensitive. In this study, we analyzed (using classical statistical methods) spatial and temporal variations in soil water content (SWC) from 14 September 2016 to 22 April 2019 for high and low vegetation in two grassland sites in Yanchi County, Ningxia. The results showed that the largest average seasonal SWC occurred in autumn. The SWC of the first three layers (0 ÷ 15 cm) of the soil profile responded strongly to precipitation, whereas the SWC in deeper soil (30 ÷ 50 cm) could only be recharged markedly after continuous precipitation. Additionally, the growing process of plants proved to be a cause of variability in soil moisture profiles. Vegetation degradation sped up the course of desertification and decreased soil organic carbon content. These changes left the soil increasingly desiccated and enhanced soil variability. Meanwhile, vegetation degradation also prompted changes in soil temperature and shortened the soil’s frozen time in winter. With the acceleration of global warming, if the process of vegetation degeneration continues and soil temperatures keep rising, the ecosystem is likely to undergo irreversible degradation.

Tsallis q-Stat and the Evidence of Long-Range Interactions in Soil Temperature Dynamics

“…The raining season in Nigeria varies for different locations with longer rainy seasons in the south and shorter rainy seasons in the northern part of Nigeria. A good number of investigations have established that the soil water content is a strong determinant factor in soil temperature regulation [ 1 , 10 ].…”

“…However, the underlining dynamics of both systems are different and as such, the intrinsic complex dynamics of the soil temperature propagation and the various factors affecting the thermal diffusivity of the soil are the major determinants of its internal temperature dynamics. The complexities in soil dynamical processes in aspects such as the soil hydrology have been evaluated using the entropic approach and it has been able to reveal the variations of soil dynamics resulting from varying hydrological processes [ 10 , 11 ], which usually affects the temperature variation [ 1 ]. The other intrinsic factors affecting the soil thermal diffusivity include soil vegetation cover [ 1 , 3 , 8 , 12 ], soil colour, soil texture and soil organic carbon [ 1 , 3 , 7 , 8 , 12 ].…”

Influence of Coal Gangue Mulching With Various Thicknesses and Particle Sizes on Soil Water Characteristics

“…Before the soil columns were lled, petroleum jelly was smeared evenly on the inner walls of the PVC pipes to eliminate the in uence of water-dominant ow along the walls. When the soil columns were lled, the layers of raw soil were roughened individually to connect the soil pores, and bulk density was limited to 1.4 g/cm 3 . Six small holes with diameters of 1 cm were evenly drilled at the bottom of the PVC pipe for soil water drainage and ventilation.…”

“…However, natural rainfall is scarce in semi-arid and arid regions and rainwater evaporation occurs more intensely, which are problems that require a prompt solution to ensure maintenance of agricultural productivity [1][2]. Suppressing evaporation and increasing water availability is critical for natural vegetation restoration [3]. In this regard, mulching can prohibit the loss of soil water by wind, decrease soil evaporation, and improve the soil hydrothermal status and ecological activity; moreover, it is an important technique for sustaining soil water storage [4][5].…”

Soil respiration and its temperature sensitivity to different ecosystems in Annapurna Conservation Area, Nepal

“…The source of water in the soil of the study area is rain or morning dew, snowmelt (NGWA, 2018) or nearby water canals causing groundwater flow and activity of capillary action (Saberian & Jahandari, 2017). Supporting the processes to maintain water balance in soil keeps fluctuating due to soil temperature variation at a different time (Yang, 2019).…”