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This study was carried out to assess the influence of tillage systems on soil characteristics as well as barely yield. The two-year experiment with the tillage systems (NT, no-tillage; MT, minimum-tillage; and CT, conventional-tillage) and barley cultivars was done. Vetch was pre-planting in the rotation with barley. About 30% of vetch residue remained in the NT and MT systems, but in CT, these residues were buried by moldboard. Results showed that NT was superior to MT and CT in terms of the soil properties, earthworm number and earthworm body mass. Remains of vetch, as a pre-planted crop, were effective in increasing these indicators. Also, the improvement of these indicators made the no-tillage superior to the MT and CT in terms of geometric mean diameter, mean weight diameter and soil moisture content. In contrast, soil porosity was higher in CT system. In conclusion, soil structure improved during the two years of the experiment when MT or NT was used, while CT was not effective in improving the soil structure. Grain yield (5973 kg ha−1) and NFS (5163) were higher in NT than MT and CT, suggesting that the change in soil structure has provided a better environment for the yield. [ABSTRACT FROM AUTHOR]

Understanding the spatial patterns of soil microbial communities and influencing factors is a prerequisite for soil health assessments and site-specific management to improve crop production. However, soil microbial community structure at the field scale is complicated by the interactions among topography and soil properties. The objectives of this study were to (1) characterize the spatial variability patterns of soil microbial communities at the field scale; (2) assess the influence of soil physico-chemical properties, topography and management on soil microbial biomass spatial variability. This study was conducted in a 194-ha commercially-managed field in Hale County, Texas, in 2017. A total of 212 composite soil samples were collected at 0–0.15 m depth and analyzed via the ester-linked fatty acid methyl ester (EL-FAME) method to characterize the microbial community structure and biomass. Soil electrical conductivity (EC), pH, soil texture, soil water content (SWC), soil organic carbon (SOC) and total nitrogen (TN) were determined for each soil sample. Topographic attributes, including elevation and slope, were derived from real-time kinematic (RTK) point elevation data. Interpolated microbial community maps at this scale revealed a spatially structured distribution of microbial biomass and diversity with patches of several hundred meters in different directions corresponding to the distribution of soil types and topography. Most of the microbial communities were autocorrelated at greater ranges within the same soil types than across different soils. The distribution of total soil microbial biomass was mainly affected by SOC and SWC. Soil pH and C:N ratio had a negative impact on the biomass of bacterial communities. Biomass of fungal communities was negatively influenced by slope and elevation. The results of this study have the potential to provide a basis for designing soil sampling plans in characterizing microbial community distribution and site-specific soil health management. [ABSTRACT FROM AUTHOR]

Herbaceous vegetation is of great ecological importance and responds quickly to environmental changes. The present study was aimed to understand the variation in herbaceous species composition, biomass and soil physico-chemical properties in the naturally formed gap and the understory of semi-arid forests in the Aravalli hills. Four permanent plots consisting of the gap as well as the understory were established. To study herbs phytosociological attributes and biomass, 10 quadrats of 0.5 × 0.5 m size were laid in each plot. For soil physico-chemical properties, 5 soil samples were collected randomly at 0–10 cm depth from each plot. Relationships among biodiversity indices, herbaceous biomass and soil physico-chemical properties were determined using Redundancy Analysis (RDA) and correlation analysis. Across the sites, Poaceae was the dominant family. All species showed a contagious distribution pattern. In the understory, Importance Value Index (IVI) was the recorded highest for Oplismenus burmannii, ranging from 138 to 230.5 while in the gap, it was the highest for Achyranthes aspera (56.15) followed by Eragrostis ciliaris (53.1). Both sites included, herbaceous community biomass in the gap ranging from 700 to 900 g m−2 while in the understory it ranged from 30 to 70 g m−2. Cenchrus ciliaris (597.97 g m−2) and Chrysopogon sp. (391.2 g m−2) contributed a major proportion of herbaceous community biomass in the gap. Oplismenus burmannii (52.2 g m−2), Dipteracanthus prostratus (16.6 g m−2) and Cynodon dactylon (9.6 g m−2) contributed a major proportion of herbaceous community biomass in the understory. The understory soil had significantly (p < 0.05) higher soil moisture (%), electrical conductivity (EC), soil organic carbon (SOC) and soil total nitrogen (TN) compared to the gap. Even though canopy had positive effects on soil physico-chemical properties, it has negatively influenced herbaceous species composition, diversity and biomass, due to significant reduction in solar radiation reaching the ground. [ABSTRACT FROM AUTHOR]

Cultivation of legume plants is well known to improve soil N level and net primary productivity; besides, it may deliver other ecosystem benefits such as increasing soil carbon sequestration and soil food web complexity. However, little is known about whether legumes can improve the resistance of soils to ecosystem disturbances. In the present study, we compared the resistance of soils to an ecosystem disturbance (understory removal) in the presence or absence of a legume species (Cassia alata) in mixed tree species plantations in southern China. Soil physico-chemical and biotic properties were employed to quantify the resistance of soils to understory removal. Our results showed that the resistance indices of soil water content, omnivorous-predacious nematode abundance and nematode channel index to understory removal were greater in the presence of legumes than those without legumes in wet season. The resistance indices of fungal to bacterial ratio, fungivorous nematode abundance and total arthropod abundance were greater in the presence of legume than those without legume species in dry season. Our results indicate that legumes may enhance the resistances of soil physico-chemical and biological properties to the ecosystem disturbance. Our findings could provide a better understanding of the myriad ways in which legumes can positively affect ecosystem functioning. [ABSTRACT FROM AUTHOR]

Abstract: In order to determine the best combination of the most adaptable shrub, the irrigation frequency (IF) and irrigation amount (IA) in the Tarim Desert Highway Ecological Shelterbelt Project, we investigated the soil moisture (SM), soil electrical conductivity (EC) and shelterbelt shrubs height (SH) where the plants were irrigated with the saline groundwater (5gL−1) bumped from the local wells. And an orthogonal array experiment was set to test the effects of the species, IF and IA on the plants height. When the different irrigation ways were used to irrigate the shelterbelt plants, significant differences in plant species heights, soil moisture, and salt accumulation on the surface were found. All of these findings suggested that the IF 20-day with IA 30mm every time was the better choice in which the soil moisture was above 2%, little salt accumulated on the dune surface and the most plants’ height occurred. Our results indicated that species was the more important factor to concern than IF and IA when the IA was above 15mm with the IF less 30-day. The shrub traits determined greatly the growth status. And Haloxylon ammodendron was the best species selected among the three main shelterbelt shrubs, Tamarix taklamakanensis, H. ammodendron and Calligonum caput-medusae in the ecological shelterbelt project. Multivariate orthogonal array designs provided an effective strategy to determine the optimum irrigation management of individual additive components to the shelterbelt shrubs in the Tarim Desert Highway Ecological Shelterbelt Project. [Copyright &y& Elsevier]

In semi-arid environments like Zagros (western Iran), soil properties are influenced by vegetation cover particularly tree species. This research addressed the effect of three oak (Quercus brantii Lindl.) growth types (seed-origin trees, old and young coppice forms areas) on soil physio-chemical and biological properties along an elevation gradient. Soil sampling was carried out at two soil depths (0–5 and 5–25 cm) and three elevations (low, middle and high) in the three types of growth and in treeless area. We found lower values in soil nutrients, carbon sequestration, soil moisture and microbial activities in the open area than beneath the vegetation cover at all elevations. There was a significant influence of the type of growth: values of most of the biological and chemical properties were lower in the young coppice type than in the old coppice type and seed-origin trees. We also found negative correlations between carbon sequestration and microbial biomass nitrogen and basal respiration in all types of growth. These results thus emphasize the role of patches of woody vegetation in creating 'islands fertility'. The type of growth significantly influence soil properties through the whole elevation gradient and the old seed-origin type was the most favorable for soil fertility. • Soil properties improved with increasing canopy cover. • Soil fertility decreased with soil depth but did not vary significantly according to elevation. • Patches of woody vegetation create 'islands of fertility'. • Conservation of these patches is essential in semi-arid areas. [ABSTRACT FROM AUTHOR]

This study was undertaken to develop new pedotransfer functions (PTFs) for the estimation of soil moisture content at field capacity (FC, at −33 kPa) and permanent wilting point (PWP, at −1500 kPa) for South African soils based on easily measurable soil physico-chemical properties. The new PTFs were developed using stepwise multiple linear regressions with the dependent variable (either FC or PWP) against clay, silt, sand and soil organic carbon (SOC) content from a total of 3171 soil horizons as the explanatory variables. These new PTFs were evaluated and compared with five well-established PTFs using a total of 3136 soil horizons as an independent dataset. The coefficient of determination (r2) values for the existing PTFs ranged from 0.65–0.72 for FC and 0.72–0.81 for PWP, whilst those developed in this study were 0.77 and 0.82 for FC and PWP, respectively. The root mean square error (RMSE) values for the well-established PTFs ranged from 0.052–0.058 kg kg−1 for FC and 0.030–0.036 kg kg−1 for PWP, whilst those developed in this study were 0.047 and 0.029 kg kg−1 for FC and PWP, respectively. These findings suggest that PTFs derived locally using a large number of soil horizons acquired from different agro-climatic locations improved the estimation of soil moisture at FC and PWP. Due to the range of conditions and large soil datasets used in this study, it is concluded that these new PTFs can be applied with caution in other regions facing data scarcity but with similar soil types and climatic conditions. [ABSTRACT FROM AUTHOR]