Soil organic carbon and labile and recalcitrant carbon fractions attributed by contrasting tillage and cropping systems in old and recent alluvial soils of subtropical eastern India

Conservation agriculture-based sustainable intensification (CASI) technologies comprising zero-tillage with crop residue retention (>30%) on the soil surface, diversified cropping systems, and balanced nutrient management are recognized as operative and efficacious strategies to ensure food security in the parts of South Asia. The present investigation was a component of CASI technologies undertaken in the farmers’ field of Malda (old alluvial Inceptisol) Coochbehar (recent alluvial Entisol) district, West Bengal (subtropical eastern India). This study was conducted to evaluate the short-term impact of contrasting tillage (zero and conventional) and cropping systems (rice–wheat and rice–maize) on total organic carbon (TOC) and its fractions, viz., labile pool-1 (LP1), labile pool-2 (LP2) and recalcitrant carbon (RC) fractions after 4-year trial of conservation agriculture (CA) in the old and recent alluvial soils. Soil samples were collected from three depths (0–5, 5–10, and 10–20 cm), and thus, our study was focused on two factors, viz., cropping system and tillage. Results pointed that TOC along with LP1, LP2, and RC fractions under rice–maize (RM) cropping system were significantly (p<0.05) greater (15–35%) over rice–wheat (RW) system as a result of higher residue biomass addition. Zero-tillage (ZT) improved the C fractions by 10–20% over conventional tillage (CT) in all aspects. TOC and its fractions were observed to be greater under the ZT system in the topmost soil depths (0–5 and 5–10 cm), but the same system failed to improve these at 10–20 cm. Interestingly, the CT increased all the fractions at 10–20 cm depth due to the incorporation of crop residues. The concentration of TOC along with its fractions decreased with increasing soil depth was evident. Comparatively, all the C fractions, including TOC were maximum in soils from Malda sites as compared to Coochbehar sites because of a higher amount of residue biomass application, higher clay content, and greater background content of C in these soils. All the studied C fractions showed a significant correlation (r = >0.635; p<0.01) with TOC among all the soil depths in both the districts but the relationship with soil texture showed some interesting results. TOC fractions were significantly correlated (p<0.01) with clay particles indicating that its higher stabilization with clay in old alluvial Inceptisol (Malda); while in recent alluvial Entisol (Coochbehar), sand particle showed its strong relation with TOC fractions. Higher stratification ratio (SR) in the ZT system suggested that the concentration of TOC and its fractions are confined to the upper soil layers whereas in the case of CT, by and large, the distribution of these was comparatively high in subsequent soil depths due to residue incorporation effect. The concentration of C fractions in soils followed the order: TOC > RC > LP2 > LP1. The present investigation concluded that ZT under the RM system increases the turnover rates of C in both soil types but the amount of clay influences the stabilization/storage of C.

Modes of occurrence of tungsten in alluvial soils and river sediments in the area of the Grantcharitsa tungsten deposit, Western Rhodopes, Bulgaria

A distinct increase in the concentration of W in the topsoil (from 19–20 to 71 ppm) is found in the vertical profile of the alluvial soil at the Grantcharitsa deposit. The distribution of W, Fe, and C is well correlated, which indicates a significant role of organic material and iron oxides/hydroxides formed in the soil in the chemical behavior of W. The role in these processes of scheelite, W-containing goethite and rutile identified in the soil is insignificant.

Grain yield of repetitive mung bean variety Marjon, after autumn wheat

The article presents the dependence of mung beans yield on the number of pods and in the care of variety “Marjon” as a recurring crop in alluvial soils of meadows in Bukhara region, equalities are revealed, that is, the coefficient of determination r = 0.6108, the coefficient for determining the mass of beans r = 0.8183, the coefficient of determination of the grain mass r = 0.6431; The coefficient of determination of the number of beans in the Durdona variety r = 0.4415, the coefficient of determination of the weight of beans was r = 0.5954 and it is recommended to sow in the second half of June at the rate of 18 kg/hectare of seeds per hectare and water at the rate of N-60, P-80, K-60 kg/hectare and 70-70-65% of the maximum soil moisture before irrigation.

Influence of elements of irrigation technology of medium and late varieties of soybean on soybean yield

In this article, under the conditions of alluvial soils of the Bukhara region, the main yield in the care of mid-ripening varieties of soy “Nafis” and late-ripening varieties of “Uzbek-6” is 4 times., With 714 m3./ha once before flowering, 739-763 m3/ha 3 times from flowering to the end of the application period, 3016 m3/ha with seasonal irrigation, 35,1737.8 with black film irrigation on wheat c/ha of soybean crops, 6 116 000 soums - 7 million soums Net profit amounted to 196 thousand soums, profitability increased by 77.2-90.8%.

Impact of Conservation Agriculture and Cropping System On Soil Organic Carbon and Its Fractions in Alluvial Soils of Eastern Gangetic Plains

Purpose A conservation agriculture-based sustainable intensification (CASI) practices have been proposed as a potential alternative management strategy for achieving the food, water and energy security while sustaining the soil health and climate resilience. In this study, we evaluate the performance of CASI technologies under two cropping systems on carbon (C) dynamics in the soils of recent and old alluvial nature of West Bengal in Eastern Alluvial Ganga Plains. Methods The on-farm field study was undertaken for four years during 2014-15 to 2018-19 with an objective of long-term setup at Coochbehar and Malda districts, West Bengal (subtropical eastern India). The two cropping systems (rice-wheat, RW and rice-maize, RM) and two tillage options (zero tillage, ZT and conventional tillage, CT) were evaluated on multi-location at farmers’ field to see the impact on soil total organic carbon (TOC) and its fractions, stratification, and stocks. Results About 20% higher TOC concentration was observed in the old alluvial soils (Inceptisols of Malda district) as compared to recent alluvial soils (Entisols of Coochbehar district). TOC and its fractions significantly (p<0.05) improved under RM cropping system than that under RW. The ZT system enhanced the TOC and its fractions by 16.8 and 9.8 % over CT at 0–5 and 5–10 cm respectively. All the C fractions showed strong positive correlation (r= >0.85; p < 0.01) with TOC except POC. Conclusions Our research indicated that ZT system increased the C turnover rate in both soil types which was found more prominent in RM system.

Trace element content in alluvial soils landscape of the flood plains of the Iput river

The results of research on the content and distribution of trace elements in alluvial soils of various elements of the floodplain landscape, and their relationship with fertility indicators are presented. It has been found that the maximum concentrations of most trace elements (Ni, Zn, Mn, Cr, Co, Mo, As) are characteristic of the alluvial overhanging-marsh heavy-coal pristine subsystem of the floodplain landscape. In the riverine and perish subsystems of the floodplain landscape in individual layers of the corresponding soils, an excess of clark was found: in the alluvial sour acid layered primitive shortened sandy loam Cu by 1.5; Zn in 1.1; Cd 9.2 times, in alluvial chilli-marsh heavy-coal Cu 1.05; Zn in 1.4; Mn in 1.01; Cr in 1,2; Cd 3.2 times. For the riverine and perch subsystems, the excess of Cu, Mn and Cr was observed in the soil layer 0-5 cm, the remaining exceedances are characteristic of deeper layers. Decreasing rows of trace elements in alluvial soils have a similar structure. The microelements in question, in the soils of the floodplain landscape of the Iput River, in terms of clark concentration, belong to the group of dispersing. There is no significant correlation between micronutrient content and fertility of the alluvial soils under consideration.