Evaluating patterns of soil health and soil-water dynamics in different land uses in a semiarid area of Texas High Plains

Date

2022-08

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Abstract

Sustainable land use is essential for maintaining soil capacity to meet current and future generations' food and fiber demands while preserving and improving the quality of soil, water, and air resources. However, unsustainable land-use practices can result in soil degradation, negatively affecting soil health, and the associated declines in soil health can adversely affect soil ecosystem functioning. Organic matter and microbial biomass in the soil, on the other hand, can promote soil health and potentially support the soil's continued ability to provide ecosystem services. The accelerated intensive land-use practices and challenges in sustainable land management, combined with deteriorating soil health and water scarcity, highlighted the need to build sustainable land-use systems in semiarid regions. The study was carried out with an objective to examine how different land uses have affected major soil health parameters, such as soil organic matter, microbial biomass, soil water depletion, and soil water content in the soil profile. Our first study analyzed the differences in two key soil health indicators, soil organic matter, and microbial biomass carbon, in response to land use and soil depth in the semi-arid area of Texas High Plains, during the growing season of 2021. We conclude that effective land-use adaptation could sequester more carbon in the soil across the entire depth profile, thereby improving soil health. Higher soil organic matter content and microbial biomass can positively impact soils, as they can provide better aggregate stability, increase in-filtration, and reduce compaction. Our study is only one of few that directly compares a disturbed to a more natural ecosystem to examine the potential for soils to store more carbon across the depth profile (within the 80 cm soil profile). We found that the topsoils under dryland and irrigated cotton cropland have a soil carbon storage potential (in soil organic matter) of 0.99% and 0.76%, respectively, which was 15.15% and 35.17% lower than the soil carbon storage potential (in soil organic matter) of a natural ecosystem (1.16%) in this region. Meanwhile, the soil carbon storage potential (in soil organic matter) of subsoils under dryland and irrigated cotton cropland was 0.74 % and 0.57 %, respectively, which was 16.69 % and 35.27 % less than the soil carbon storage potential (in soil organic matter) of a natural ecosystem (0.88 %) in this region. This information can quantify how much soils can mitigate climate change by trapping more carbon. Overall, our findings add empirical support to the need to consider subsoil as an important Carbon sink that could contribute significantly to global carbon sequestration and thus influence climate change. According to the findings of our second field study, soil water depletion was maximum in the topsoil and shallow soil depths in all three land uses, resulting in higher evapotranspiration loss in the top and shallow soil depths than in deeper soil. Topsoils and shallow soils showed very large moisture fluctuations, indicating that they get wet easily and dry quickly due to high evapotranspiration loss. However, the deeper you go into the soil profile, the less the moisture fluctuates, indicating that soil moisture is more dependable in the deeper soil. As a result, deep-rooted crops and plants may be advantageous to this region in order to access stable soil moisture of deep soil. Information on the rate of soil water depletion in the topsoil and shallow soil depth (up to 40 cm) in dryland cotton can assist growers in managing water toward maintaining higher moisture levels in this layer to meet crop water requirements in severe conditions. It can also help introduce water conservation strategies (such as mulching, residue, cover crop, etc.) to reduce evapotranspiration loss and sustain dryland agriculture in the region. The soil water content varied in the soil profile of all three land uses, implying a varied capability for infiltration in the Texas High Plains. The finding also indicates the necessity of conserving stable soil moisture and organic matter through natural land use, especially in semiarid areas with low annual rainfall and high evapotranspiration demand. It can promote stable soil water content, which has important implications for developing sustainable agriculture and grassland from the viewpoint of soil and water conservation in the semiarid area.


Embargo status: Restricted until 09/2027. To request the author grant access, click on the PDF link to the left.

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Keywords

Land-Use, Soil Depth, Organic Matter Content, Microbial Biomass Carbon, Soil Carbon, Soil Health, Soil Water Depletion, Water Content

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