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Agricultural management practices alter soil characteristics and influence soil biological properties. Hence, a field trial was carried out to assess the 14-year long-term impact of tillage and residue management practices on soil biological activities and microbial population in a rice-wheat cropping system in two depths viz., 0-15 and 15-30 cm. Soil organic carbon levels differed significantly (p > 0.05) across various treatments. Microbial biomass carbon, microbial quotient, and soil enzymatic activities were significantly greater (10-82%) in crop residue incorporation/retention treatments. Zero tillage with residue retention (ZT+R) had the greatest bacterial, actinomycetes, and fungi population, followed by reduced tillage with residue incorporation (RT+R). The ZT+R treatment had the greatest value of K-strategist and r-strategist, and was equivalent to RT+R across both soil depths. When compared to conventional tillage (CT), zero tillage (ZT) increased wheat yield by 9%. However, compared to CT, rice and rice-wheat systems had lower grain yields, whereas crop residue increased wheat and rice-wheat system yields by 10% and 6%, respectively. The findings of this long-term study show that residue management and tillage practices can enhance soil biological attributes while also supporting microbial diversity. [ABSTRACT FROM AUTHOR]

Fluvial landscapes in the dry land parts of the world include soils with large quantities of soluble sodium carbonates and bicarbonates and abundant exchangeable sodium. The Indo-Gangetic alluvial plain (IGP) includes a large proportion of salt-affected soils in India of these 3.78 million hectares are sodic soils. Considering the problem of soil sub-surface sodicity the ICAR-Central Soil Salinity Research Institute (CSSRI), Karnal, and the Japan International Research Centre for Agricultural Sciences (JIRCAS) have con- ducted a farmers' field trial from 2019 to examine the effects of gypsum and rice residue placement by Cut-soiler machine at various lateral spacing on soil sub-surface sodicity and crop yield. The treatments include Cut-soiler assisted sub-surface application of gypsum, rice residue and gypsum + rice residue at 2.5, 5.0 and 10.0 m of lateral spacing. The result shows appreciable temporal and spatial re- duction in sub-surface sodicity and consequently increases in wheat yield during study period (2019-2021). The reduction in soil pH at 0.1 m, 0.4 m, 0.8 m and 1.2 m from Cut-soiler drain was recorded and it was observed that the reduction in soil pH was continuous and consistent from year 2019 to 2021. There was higher reduction in soil pH near to the Cut-soiler drain and this reduction was decreased with increase in distance from Cut-soiler drain. The soil pH reduced by 0.8 units (8.9 to 8.17) at 0.1 m distance in 2021. The soil pH at 0.4 m, 0.8 m and 1.2 m were 8.27, 8.46 and 8.67, respectively in same year. The wheat yield in 2.5 m lateral Cut-soiler drain was 18.3% higher than without Cut-soiler. Sub-surface sodicity management by placement of amendments along with filling material in Cut-soiler drains in turn further helped to increase grain yield of wheat and thus the amelioration effect was continuous and consistent. [ABSTRACT FROM AUTHOR]

Arid and semi-arid regions experience less rainfall and high evaporation rates and are very sensitive to land use transitions. Salt-induced soil degradation is one of the major constraints in arid and semi-arid regions of India. In India about 6.73 Mha land is salt affected out of which around 3.78 M ha is under sodic soils. Around 2.5 M ha area is covered under salt affected soils in Indo Gangetic Plains (IGP), the most fertile landmass. Besides infelicitous crop management practices, injudicious use of sodic water possess grave risks to soil health. High Residual Sodium Carbonate (RSC) restricts the natural drainage, a rationale to surface and subsurface sodicity development. On farm residue burning is also a burgeoning problem in the semi-arid region of IGP where rice-wheat cropping system is predominantly followed. Fathoming the twin problem of sub-surface sodicity and residue burning the column study in semi-controlled condition is being conducted under ICAR-Central Soil Salinity Research Institute (Karnal) and the Japan International Research Center for Agricultural Sciences (JIRCAS) collaborative project. The treatments consisted surface application of gypsum (SA), surface and sub-surface placement (50 cm below the surface) of rice straw residue and gypsum that is an imitation of sub-surface Cut-soiler assisted drains in field condition. The columns were irrigated with water having RSC <2 meql-1 and ~5 meql-1. The results showed that comparatively the higher reduction in soil pH was recorded in the columns irrigated with RSC <2 meql water as compared to ~5 meql under surface application of gypsum along with sub-surface application of gypsum and residue both. Consequently, the rice yield increase about 31% and 23% in the foresaid treatment as compared to control. Therefore, surface application of gypsum along with cut-soiler assisted sub-surface placement of amendments found promising in reclamation of sub-surface sodicity and increase rice yields under sodic soils. [ABSTRACT FROM AUTHOR]

In India, about 6.74 M ha area is salt-affected, out of which saline and sodic soils account for approximately 2.95 and 3.79 M ha, respectively. About 5.5 M ha area also suffers from problem of waterlogging in the country. The management of saline soils often requires higher drainage intensity for quick leaching of salts from the soil profile; however, the existing drainage techniques involve heavy machinery and higher cost. Cut-soiler is a tractor-mounted, easy to use farm implement that constructs residue filled sub-surface drains. It uses surface scattered crop residue as filling material for preferential water flow to drain out excess water and salts from the operated area. This semi-controlled lysimeter study was conducted at ICAR-Central Soil Salinity Research Institute (CSSRI) in collaboration with 3) Japan International Research Center for Agricultural Sciences (JIRCAS) during 2019-2021. The simulated Cut-soiler drains were constructed in 12 lysimeters along with 12 control (without Cut-soiler) as main plots. The two soil types i.e. saline (light textured sandy loam) and non-saline (heavy textured silty clay loam) were laid as sub plot treatments and three irrigation water salinity (4, 8, 12 dS m-1) were applied in sub-sub plots in two replications. The Cut-soiler resulted in higher outflow of free water and salts with drainage during events of irrigation and rainfall. Hence, Cut-soiler reduced ~60% soil salinity after two years and improved mustard yield of successive crops. The Cut-soiler treatment significantly increased mustard seed yield by 31.5% over control. The Cut-soiler could be an effective technique for salinity, it can even be applied at individual farm level in a single operation. [ABSTRACT FROM AUTHOR]

Salinization is a long-standing problem that has threatened crop production and food security in arid and semi-arid regions. Salt accumulation in the root zone results in loss of soil fertility and alters the soil properties and therefore harmfully impacts soil's environmental functions. To alleviate the impact of soil salinity, various technical measures and strategies have been developed over time. Cut-soiler constructs residue filled Preferential Shallow Sub-surface Drains (Cut-soiler PSSD) to enhance outflow of salts and manage the root zone salinity even with the simultaneous irrigation of saline groundwater for sustainable production. This field study was conducted (2018-2021) to standardize the optimum lateral spacing of Cut-soiler PSSD in saline field. Cut-soiler PSSD was con- structed at 2.5-, 5.0-, 7.5- and 10.0-meter lateral interval at a depth of 60 cm using rice residue as a filling material @ 6 Mg ha-1 and control (without Cut-soiler). The Cut-soiler PSSD reduced soil salinity from its construction in May 2018 to April 2021. After three years of Cut-soiler PSSD operation, the highest reduction in Electrical Conductivity of extract of saturated soil (EC) i.e., up to 52.4% was recorded in closest lateral spacing of Cut-soiler PSSD drains i.e 2.5 m as compared to initial EC, values. The lateral spacing of 5.0, 7.5 and 10.0 m reduced 38.7, 35.9 and 31.4% salinity (EC), respectively over their corresponding initial EC, values. The narrowest lateral spacing of Cut-soiler PSSD was found to reduce soil salinity up to 52.4% over no Cut-soiler plots. Therefore, closer spacing (2.5 m or less) found promising for salinity management in highly salt-affected fields for sustainable agricultural production. [ABSTRACT FROM AUTHOR]