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Applying biochar to saline soil is a novel strategy for improving soil quality. However, how biochar addition amount affects soil nutrients, bacterial communities, and cotton growth at different stages remains unclear. Three biochar treatments, no biochar (BC0), 1% biochar (BC1, w/w), 3% biochar (BC3), and two cotton varieties, salt‐sensitive (SS) and salt‐tolerant (ST), were used in pot experiments, analyzing biochar effects on saline soil nutrients, bacterial communities, and cotton growth. The study found that biochar increased only organic carbon (SOC), total nitrogen (TN), and available potassium (AK) at the seedling stage. However, at the flowering‐boll stage, biochar also increased nitrate (NO3−–N) and available phosphorus (AP) and reduced soil salt content. Biochar did not affect α‐diversity at the seedling stage, but BC3 reduced α‐diversity at the flowering‐boll stage. The principal coordinate analysis revealed changes in the soil bacterial community composition that were closely associated with biochar added. From the redundancy analyses, SOC and AK were the leading environmental factors for soil bacterial community composition changes. SOC, TN, and AK correlated positively with Proteobacteria, which increased their relative abundance through biochar addition and correlated negatively with Bacteroidetes, Chloroflexi, and Acidobacteria, which decreased their relative abundance due to biochar. Furthermore, the random forests analysis showed that SOC, Shannon index, and β‐diversity were significant predictors of cotton biomass. In summary, biochar drives changes in bacterial communities in saline soils by increasing nutrients such as SOC and AK, which affect cotton growth. This study provides data to support the application of biochar on saline soils. [ABSTRACT FROM AUTHOR]

Waterlogging and salinization are considered to be the main threats to agricultural productivity and land resources in coastal areas of China. Thus far, drainage and field soil improvement programs have been ineffective. In this article, we investigated the effect of subsurface drainage combined with biochar (B–S) on soil physicochemical properties and soil bacterial community structure in coastal saline soil. In this study, B–S significantly reduced soil electrical conductivity (EC) and soil water content (W) by 35% and 10.65% compared to no drainage (CK). Compared to CK and drainage alone (S), B–S significantly increased soil total nitrogen (TN) by 24.78% and 39.62%, soil available phosphorus (AP) by 28.29% and 69.82%, soil nitrate (NO3−-N) by 64.65% and 35.45%, and significantly increased soil organic matter (SOM) by 74.69% and 66.10%, respectively. It also significantly increased alkaline phosphatase (ALP) and urease activities. The results of redundancy analysis (RDA) showed that CAT and urease made the greatest response to changes in environmental factors, indicating that CAT is more sensitive to changes in environmental alterations than ALP. AP was the dominant factor in the change in enzyme activity (R2 = 53.0%, p < 0.05), followed by NO3−-N (R2 = 14.8%). SOM was the dominant factor in the variation in microbial abundance content (R2 = 38.5%, p < 0.05), followed by ALP (R2 = 20.0%, p < 0.05). The results of the study can provide guidance for effective land use and sustainable development of agricultural soil ecology in coastal areas. [ABSTRACT FROM AUTHOR]

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As one global issue, soil salinization has caused soil degradation, thus affecting the sustainable development of irrigated agriculture. A two-year study was conducted in 2018 and 2019 to identify the effects of subsurface drainage spacing on soil salinity and groundwater level, the latter of which is in a high-water table in drip irrigation cotton fields in the Tarim Basin oasis in southern Xinjiang, China. Three subsurface drainage treatments, with a drain spacing of 10 m (W10), 20 m (W20), and 30 m (W30), respectively, and a drainage-absent treatment (CK), are tested. With CK, soil salinity in the 0–60 cm layer was accumulated within a year. In contrast, the subsurface drainage reduced the soil salinity at a leaching rate of 10–25%. When decreasing the drain spacing, it was found that the soil desalination rate increased significantly (p < 0.05) with good repeatability. Experimental results showed that the fitting equation of the soil salinity leaching curve could accurately describe the soil salinity leaching pattern of drip irrigation, and thus could be further used to inversely determine the theoretical drip irrigation leaching quota for those soils with different salinity degrees. As such, subsurface drainage could effectively control the groundwater table. Compared with CK, subsurface drainage deepened the groundwater table and mitigated the fluctuation of the groundwater level. These effects were strengthened by reducing the drain spacing. Correspondingly, the influence of the fluctuation of the groundwater table was reduced. [ABSTRACT FROM AUTHOR]

Soil salinization is a global issue that results in soil degradation and affects the sustainable development of irrigated agriculture. A 2-year study was conducted in 2018 and 2019 to identify the effect of subsurface drainage spacing on soil moisture, salt, cotton growth, and yield under the Tarim Basin oasis in China. The tests involved three subsurface drainage treatments, with a pipe spacing of 10 m (W10), 20 m (W20), and 30 m (W30), respectively, and a drainage-absent treatment (CK). Compared with CK, subsurface drainage reduced soil salinity, resulted in better uniform water distribution and reduced inorganic salt concentration in shallow soil solution. In addition to improving soil moisture and salinity conditions, subsurface drainage increased seedling emergence rate (28%), root vigor (23%), and chlorophyll content (44%) of cotton, which in turn led to increases in cotton plant height (18%), leaf area (33%), dry matter weight (32%), and reproductive organ weight (39%), thereby resulting in high cotton yield (45%). A path analysis revealed that under subsurface drainage, the seedling emergence rate of cotton had the greatest impact on cotton yield, and subsurface drainage contributed the most to the increase in cotton yield. It increased the seedling emergence rate by reducing soil salinity. Moreover, cotton yield and next-year soil arability increased with decreasing drainage pipe spacing, suggesting that it is advantageous to adopt a drainage pipe layout with small pipe spacing when economic costs are not a concern. [ABSTRACT FROM AUTHOR]

The global demand for cotton makes sustainable cotton production an important issue that can be improved by a better understanding of the influence of soil microbes on cotton growth. We collected cotton field soils at the seedling and flowering/boll-setting (FBS) stages in order to obtain soil properties and cotton growth indices. Bacterial and fungal community compositions were assessed by high-throughput sequencing of 16S rRNA and internal transcribed spacer genes, respectively, after which the differences in microbial functions and their influencing factors at different growth stages were analyzed. Both the diversity and composition of soil bacterial and fungal communities were found to be significantly different between the seedling and FBS stages. Microbes in the seedling stage had significantly higher richness and biomass than those in the FBS stage. Compared with the seedling stage, the stability of the soil bacterial communities was decreased. The cotton growth indices at both the seedling and FBS stages were associated with compositional shifts in the bacterial community and but not the fungal community. The abundance of specific soil microbial taxa (e.g., Pseudarthrobacter, Thiobacillus, Cephalotrichum, Chaetomium, and Fusarium) were correlated with cotton growth indices at the seedling stage, being mainly regulated by soil salinity and nitrate content. Our results highlight the importance of soil microbial communities in mediating cotton growth and will be useful in providing better strategies for the improvement of cotton agriculture. [ABSTRACT FROM AUTHOR]

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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The contradiction between land improvement in saline-alkali areas and water-saving irrigation in the arid regions is becoming increasingly prominent, affecting the movement of soil water and salt as well as cotton growth. To effectively improve soil quality and alleviate soil salinization issues under the premise of water conservation to increase cotton yields, a method involves conducting brackish water leaching during the non-growing season and utilizing freshwater drip irrigation during the growing season for cotton under subsurface drainage. A 2-year field experiment using six subsurface drainage systems at different depths of 0.8 and 1.1 m and different spacings of 10, 20, and 30 m respectively, alongside a non-drainage treatment as control (CK) was conducted in Aral, Xinjiang, China. Furthermore, efficient simulations of soil water and salt dynamics as well as cotton growth in arid regions under subsurface drainage conditions could be achieved using AquaCrop and DRAINMOD-S models. The results showed that soil salinity leaching could be achieved effectively with the use of appropriate brackish water and subsurface drainage pipes with the proper technical parameters during the non-growing season. Compared with the non-drainage treatment, the subsurface drainage and drip irrigation with freshwater reduced soil salinity effectively and improved growth indices and cotton yield considerably during the growing season. The rate of soil desalination exhibited an upward trend as the distance of subsurface pipes decreased, and the growth indices of cotton increased with the decrease in distance and depth of t subsurface pipes. This study concluded that using brackish water in the non-growing season, appropriate selection of irrigation water volume, spacing, and depth of subsurface pipes can simultaneously improve soil salinity drainage and cotton yield. This research suggests new irrigation and management recommendations for agricultural production and achieves more efficient water use and crop cultivation under arid conditions, providing a new insight into the efficient use of saline soil resources in the arid regions in Xinjiang. • Leaching with brackish water and drip irrigation with freshwater reduced salinity. • Subsurface drainage is beneficial to soil salt leaching and cotton growth. • Drainmod-S and AquaCrop models can simulate soil salt transport and cotton growth. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)