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Livestock, soil compaction and water infiltration rate: Evaluating a potential desertification recovery mechanism

In recent years, minimum tillage practices have been applied to sugarbeet (Beta vulgaris L.) production in northeastern Colorado to reduce soil erosion and fuel demands. The objective of this study was to compare the effectiveness of rotary‐strip, no‐plow minimum tillage to conventional plow‐based tillage on commercial sugarbeet fields under center‐pivot sprinkler irrigation relative to soil nitrate movement, weed control, stand establishment, soil compaction, field operations, yield and quality. Minimum tillage was compared to conventional plow‐based tillage in 16 center‐plot‐irrigated fields in eastern Colorado. A 0.10‐ha study site was located in a representative portion of each field. Soils were aridic Argiustoll members of the fine montmorillinitic mesic family. In the spring and midsummer, stand counts and weed counts were conducted to determine stand establishment and the effects of tillage systems on weed populations. Five‐foot deep soil cores were collected in June, July, and November to monitor nitrate movement in each field. After all field operations were completed prior to harvest, water infiltration, soil compaction, soil aggregate distribution, and aggregate stability studies were conducted to determine any differences due to tillage system. Minimum‐tilled sites had significantly lower proportions of furrow soil aggregates 6.4 mm and less in diam but had a higher percentage of aggregates 12.7 to 38.0 mm in diam. Minimum tillage significantly reduced the percentage and stability of row soil aggregates 0.84 to 6.4 mm in diameter. The stability of row and furrow aggregates decreased with increasing size. Nitrate movement was greater and larger concentrations of nitrate were moved to a depth of 75 cm under minimum tillage. The method of tillage had no effect on row and furrow bulk density, water infiltration rate, weed populations, emergence percentage, final stand, yield, quality, or recoverable sucrose. The results demonstrate that minimum tillage produced a sugarbeet crop of comparable tonnage and quality to that of conventional tillage while significantly reducing the number of field operations by 40%.

Research that connects the effects of urbanization on biodiversity and ecosystem services is lacking. Ants perform multifarious ecological functions that stabilize ecosystems and contribute to a number of ecosystem services. We studied responses of ant communities to urbanization in the Lake Tahoe basin by sampling sites along a gradient of urban land development. We sampled ant communities, measured vegetation characteristics, quantified human activities, and evaluated ant-community responses by grouping ants into service-providing units (SPUs), defined as a group of organisms and their populations that perform specific ecosystem services, to provide an understanding of urbanization impacts on biodiversity and their delivery of ecosystem services. Species richness and abundance peaked at intermediate levels of urban development, as did the richness of 3 types of ant SPUs (aerators, decomposers, and compilers). With increasing land development aerator and decomposer ants significantly declined in abundance, whereas compiler ants significantly increased in abundance. Competing models demonstrated that precipitation was frequently among the strongest influences on ant community structure; however, urban development and human activities also had a strong, negative influence on ants, appearing in most models with DeltaAIC(c) < 2 for species richness and abundance patterns of SPUs and generalists. Response diversity was observed within SPUs, which suggests that the corresponding ecosystem services were maintained until development reached 30-40%. Our data provide evidence that ecosystem functions, such as water infiltration and soil productivity, may be diminished at sites subject to greater levels of urbanization and that conserving ant communities and the ecosystem services they provide could be an important target in land-use planning and conservation efforts.

The infiltration of water into the soil decreases due to the transfer of soill function or the lack of soil biopores. This study aims to determine the effectiveness of the use of fruits waste toward the water infiltration rate. Observation of the water level decrease is done every 5 minutes interval. Observation of biopore water infiltration rate was done after fruits waste decomposed for 15 and 30 days. Result of standard water infiltration rate at the first of 5 minutes is 2.18 mm/min, then decreases at interval of 5 minutes on next time as the soil begins to saturate the water. Baraya campus soil observed in soil depths of 100cm has a dusty texture character, grayish brown color and clumping structure. Soil character indicates low porosity. While biopore water infiltration rate at the first of 5 minute interval is 6.61and 6.95 mm/min on banana waste; 5.55 and 6.61mm/min on papaya waste and 4.26 and 5.39 mm/min on mango waste. The effectiveness of water infiltration rate is 44.45% and 41.93% on banana; 44.61% and 30.09% on papaya and 15.79% and 28.36% on mango. Study concluded that banana waste causes the water infiltration rate most effective in biopore infiltration hole.

Functional stability: From soil aggregates to landscape scale in a region severely affected by gully erosion in semi-arid central Mexico

Soil physical quality response to sugarcane expansion in Brazil

Mechanical and biological chiseling impacts on soil organic C stocks, root growth, and crop yield in a long-term no-till system

Microplastics (5mm) enter the soil in several ways, including directly through the purposeful use of plastic (e.g., in plastic mulch, greenhouses, or coated items) or inadvertently through the addition of sewage sludge, compost, or irrigation water that has been polluted with plastic. The effect of microplastic on plant growth, soil biota, and soil physicochemical properties has been reviewed (Shafea et al., 2022), while soil physical properties have yet to be synthesized. Soil structure is an important soil feature affecting key variables in earth system models like, e.g., soil aggregation and soil hydraulic properties (Fatichi et al., 2020). These soil physical properties are influenced by widespread microplastic dispersion and pervasiveness, which might affect the soil's capacity to provide different ecosystem services and is a potential obstacle to sustainable agriculture (Rillig &amp; Lehmann, 2020). Thereby, we present the preliminary results of a review on the plastic and microplastic impact on soil physical properties, including soil compaction, soil aggregation, water retention and transmission, and porosity, from peer-reviewed publications. Our review indicates that increasing plastic and microplastic concentration reduces soil compaction due to changes in bulk density. Soil structure and aggregate stability are also subject to alteration due to plastic contamination. Microplastic in the soil might affect water repellency, mainly measured by water drop penetration time. However, data on hydraulic properties, thermal properties, and pore-size distribution are scant. Moreover, potential factors, i.e., plastic-type, size, concentration, and soil type, by which microplastic can influence soil physical properties, are also discussed. This communication tries to identify trends in the influence of plastic and microplastic among different treatments using different indexes. From this analysis, we identify knowledge gaps for future studies.Keywords: agroecosystem, microplastic, soil aggregates, infiltration.References Fatichi, S., Or, D., Walko, R., Vereecken, H., Young, M. H., Ghezzehei, T. A., Hengl, T., Kollet, S., Agam, N., &amp; Avissar, R. (2020). Soil structure&amp;#160;is an important omission in Earth System Models. Nature Communications, 11(1), 522. https://doi.org/10.1038/s41467-020-14411-zRillig, M. C., &amp; Lehmann, A. (2020). Microplastic in terrestrial ecosystems. Science, 368(6498), 1430&amp;#8211;1431. https://doi.org/10.1126/science.abb5979Shafea, L., Yap, J., Beriot, N., Felde, V. J. M. N. L., Okoffo, E. D., Enyoh, C. E., &amp; Peth, S. (2022). Microplastics in agroecosystems: A review of effects on soil biota and key soil functions. Journal of Plant Nutrition and Soil Science. https://doi.org/10.1002/jpln.20220013

Structure and functioning of earthworm communities in woodland flooding systems used for drinking water production

The term soil quality refers to capacity of the soil to render ecosystem services of interest to humans, and relevant to other ecological functions. Soil quality in the West Asia North Africa Region (WANA) depends on a range of properties and processes. Principal soil properties include physical (i.e., texture, structure, available water holding capacity or AWC, water infiltration rate, bulk density, soil strength, effective rooting depth), chemical (i.e., pH, cation exchange capacity or CEC, nature of exchangeable cations, intensity and capacity of plant available nutrients, electrical conductance and the concentration of soluble salts), and biological (i.e., soil organic carbon concentration and stock, microbial biomass carbon, activity and species diversity of micro and macro flora and fauna). Among these, principal determinants of soil quality for agronomic land use are bulk density, aggregation, AWC, water infiltration rate, pH, CEC, electrical conductance, nutrient reserves, soil organic carbon, and microbial biomass C. Important processes affecting soil quality are: soil erosion, decomposition of soil organic matter, soil compaction, salinization and acidification, etc. These properties and processes can be strongly affected by climate change. The latter may include increase in temperature and decrease in the effective precipitation. These climatic changes can exacerbate risks of decline in aggregation and soil structure, increase in accelerated soil erosion by water and wind, and increase in the rate of mineralization of soil organic matter content, and secondary salinization. With increase in evaporation, the frequency and intensity of droughts may increase which may reduce the use efficiencies of water and nutrients, and also adversely affect agronomic yield and net primary production. With increase in population, and the demands for food and other basic necessities, adaptation to climate change is an important strategy. The goal of sustainable soil management is to alter cropping/farming systems, crops and varieties, and timings of farming operations (i.e., planting, harvesting). Adaptations may also involve adoption of new and innovative irrigation methods such as micro-irrigation (drip sub-irrigation), shift to integrated nutrient management involving use of organic fertilizers (i.e., compost, manure, biological N fixation), and conversion to conservation tillage based on mulch farming and complex rotations. Improved grazing and low stocking rate, and integration of pastures with forage trees (agroforestry) is another useful option. While some scientific information on the recommended management practices is available for the WANA region, appropriate policies must be implemented to promote the adoption of new and innovative technologies to enhance and sustain soil quality in a harsh and changing climate.

Superabsorbent polymer (SAP) is a kind of polymer with advantages like high water absorption and conservation. We studied the effect of various concentrations of SAPs on the infiltration of soil water with sand mulching. Five soil columns with surface sand mulch and evenly distributed SAPs at concentrations of 0, 0.1, 0.2, 0.5 and 1.0% were tested. The SAPs slowed the migration of the wetting front and thus the rate of infiltration of water, and the higher the SAP concentration, the slower the migration. The relationship between the wetting front displacement and time could be described by a logarithmic function, [Formula: see text]. The amount of cumulative infiltration was inversely proportional to the amount of SAPs. The final cumulative infiltration was proportional to the amount of SAPs, within a limited range. The relationship between cumulative infiltration and time was described by a power function, [Formula: see text]. The relationship between wetting front displacement and cumulative infiltration could be characterized by a linear equation, [Formula: see text], indicating that the rate of cumulative infiltration increased with the amount of SAPs for the same infiltration depth, which satisfied the Kostiakov model ([Formula: see text]). High concentrations of SAPs strongly inhibited the infiltration of water. The infiltration rate of soil water was optimal at a SAP concentration of 0.2%, which effectively increased the amount of water in the soil.

The composition and stability of soil aggregates are important indicators for measuring soil quality, which would be affected by land use changes. Taking wetlands with different returning years (2 and 15 years) in the Yellow River Delta as the research object, paddy fields and natural wetlands as control, we analyzed the changes in soil physicochemical properties and soil aggregate composition. The results showed that soil water content, total organic carbon, dissolved organic carbon and total phosphorus of the returning soil (0-40 cm) showed an overall increasing trend with returning period, while soil pH and bulk density was in adverse. There was no significant change in clay content, electrical conductivity, and total nitrogen content. The contents of macro-aggregates and micro-aggregates showed overall increasing and decreasing trend with returning period, respectively. The stability of aggregates in the topsoil (0-10 cm) increased with returning years. Geometric mean diameter and mean weight diameter increased by 8.9% and 40.4% in the 15th year of returning, respectively, while the mass proportion of >2.5 mm fraction decreased by 10.5%. There was no effect of returning on aggregates in subsoil (10-40 cm). Our results indicated that returning paddy field to wetland in the Yellow River Delta would play a positive role in improving soil structure and aggregate stability.

Soil macroaggregate stability under different fallow management systems and cropping intensities in southwestern Nigeria

This study aims to investigate the impact of vegetation restoration on soil humus and aggregate stability within the karst region of Southwest China. This study focused on soils at five vegetation succession stages (abandoned land, grassland, shrub rangeland, shrubland, and secondary forest) in the typical karst region, and the aggregate stability was determined using wet sieving and the Le Bissonnais method. Simultaneously, the Pallo method and separation extraction were used to determine the humus composition, aiming to analyze the distribution of humus content in the soil aggregates and its effect on aggregate stability. The results revealed the following: (1) The mean weight diameter of soil aggregates significantly increased with vegetation restoration stages. Soil water-stable aggregates at each vegetation stage mainly included particles over 2 mm in size. (2) The humic acid and fulvic acid contents consistently increased with vegetation restoration, and the precipitation quotient value of the humification degree showed an increasing trend. At each vegetation restoration stage, the percentage of each humus component was, from highest to lowest, as follows: insoluble HM, fulvic acid, humic acid, clay-bound HM, and iron-bound HM. (3) Through stepwise regression analysis, humic acid content in &gt;2 mm aggregates, fulvic acid and clay-bound HM contents in 1–2 mm aggregates, and insoluble HM content in &lt;0.25 mm aggregates were the dominant factors affecting soil aggregate stability in the karst region. These results aim to provide novel insights for a more in-depth comprehension of the restoration and rehabilitation of vegetation within the karst region of Southwest China, thereby laying a robust foundation for scientific theories and further investigations.

A novel proximal sensing approach to determine soil aggregate stability is demonstrated. Change in pre‐ vs. post‐wetted aggregate reflectance yields aggregate stability (AS) from surface structure alteration. Results were well‐correlated with those of the high energy moisture characteristic (HEMC) method, which involves rapid and slow wetting of aggregates. The new method only employs rapid wetting of aggregates, saving time for sample processing and evaluation. Soil structure and aggregate stability (AS) are critical soil properties affecting water infiltration, root growth, and resistance to soil and wind erosion. Changes in AS may be early indicators of soil degradation, pointing to low organic matter (OM) content, reduced biological activity, or poor nutrient cycling. Hence, efficient and reliable AS measurement techniques are essential for detection, management, and remediation of degraded soil resources. Here we quantify soil AS by developing a novel proximal sensing technique based on shortwave infrared (SWIR) reflectance measurements. The novel approach is similar to the well‐documented high energy moisture characteristic (HEMC) method, which yields a stability ratio (SR) derived from comparison of hydraulic and structural characteristics of slowly‐ and rapidly‐wetted soil samples near‐saturation. We rapidly wetted aggregated soil samples (i.e., high energy input) and hypothesized that an AS index can be derived from SWIR surface reflectance spectra due to differences in post‐wetting surface roughness that is intimately linked to AS. To test this hypothesis, surface reflectance spectra from a wide range of structured soil textures under both slowly‐ and rapidly‐wetted samples, were measured with a SWIR spectroradiometer (350–2500 nm). The ratio between pre‐ and post‐wetting spectra was determined and compared with the HEMC method's volume of drainable pore ratio (VDPR). We found a strong correlation ( R 2 = 0.87) between the VDPR and the SWIR‐derived reflectance index (RI) and also between the SR ( R 2 = 0.90) and the RI for all soils. These results point to the feasibility and appeal of quantifying AS using the newly proposed and more time‐efficient proximal sensing method.