Alfisols

Synthetic gypsum, a by-product of electricity generation, is used as a soil amendment to overcome water ponding, improve soil and water quality, improve field conditions to support farm equipment, and reduce the variability of crop yield in no-till fields by improving hydrology. Gypsum is a source of soluble calcium (Ca) that improves physical properties of the soil by promoting clay aggregation, thereby increasing water infiltration rates and movement through the soil profile. Undisturbed soil samples from Brookston and Celina soils in Ohio, USA were collected to a depth of 75 cm in agricultural fields treated with gypsum for 0, 4, and 12 years to determine changes in chemical and physical properties. Gypsum applications increased exchangeable Ca and Ca: Mg ratios, and promoted clay flocculation and improved soil structure. Mean weight diameter of aggregates increased with gypsum treatment at most depths in both soils. Micromorphological analysis showed variations in porosity (ɸ), pore size distribution, pore shape and aggregate size related to gypsum treatment, soil, and soil depth. There were no consistent responses to years of gypsum application. Gypsum treated soils had higher po-rosity than untreated soils in all depths b75 cm and a higher percentage of micropores and mesopores compared to the control. Also, gypsum treated soils had larger aggregates than the control for all soil depths examined. Aggregates b100 μm predominated in the Brookston control soils, and b 200 μm aggregates dominated the Celina control soils. However, there was no prevailing aggregate size for gypsum treated soils. In conclusion, our study found positive effects of gypsum on most properties measured; although, not consistently related to years of gypsum applications to both soils.

Conversion of forest area to agricultural land use led to an estimated loss of 36 Pg carbon (C) from soils between 1860 and 1960. Soil organic carbon (SOC) loss through cultivation can, however, be reduced and potentially fixed in soil through proper soil and land management. The objective of this study was, therefore, to determine the effect of crop cultivation vis-à-vis forest and plantation, on the SOC concentration, especially in the plough layer, in the SOC-poor soils of Irga watershed in the tropical sub-humid dry region of Jharkhand, India. Typic Haplustalfs and Typic Paleustalfs soils predominate in the two administrative blocks within the watershed – Dhanwar and Birni, respectively. Three plots were chosen for each soil subgroup to represent three predominant land cover conditions viz. forest, plantation and mono-cropped area in Dhanwar and Birni. SOC stock was high in the Mango orchard in Dhanwar (226 Mg C ha-1); higher in the cultivated land in Birni (242 Mg C ha-1); and least in the plot under Eucalyptus plantation in Birni. In the 0-20 cm depth, Mango orchard in Dhanwar and cultivated land in both the sites showed an increase in SOC pool in comparison to forests; Eucalyptus plantation, on the other hand, registered a low SOC pool at this depth. The practice of paddy-fallow rotation and the application of animal manure led to an increase in the SOC pool in the plough layer of agricultural soils in the SOC-poor area; and thus have the potential to sequester C in the Irga watershed.

Tillage in combination with crop residue incorporation and application of fertilizer N at
different rates are the main management options for the rice-wheat cropping system in Eastern
India. A field experiment was conducted at IIT, Kharagpur to find out the impact of tillage, crop
residue and rate of fertilizer N application on soil properties and yield of rice and wheat crops.
The results of the experiment revealed application puddling increased the bulk density of soil
measured after the harvest of rice or wheat crops. Puddling also decreased the saturated
hydraulic conductivity, which in turn increased water retention of the soil and increased the yield
of transplanted rainfed rice (TR). Yield of direct seeded rice (DR) grown in soil tilled with
cultivator followed by disc harrow, was comparatively lesser than the grain yields of TR. The
tillage treatment (cultivator followed by disc harrow) for wheat succeeding both TR and DR was
same but yield of wheat crop succeeding DR was more than wheat succeeding TR. This
phenomenon manifested that the practice of puddling though increased the yield of TR, the
compaction caused by it reduced the yield of wheat crop. Incorporation of rice and wheat crop
residues either singly or in combination increased the soil organic carbon content in both of the
tillage treatments but the increase was more with dryland tillage under direct seeded rice-wheatfallow
system. The return of carbon to soil and yield of crops was maximum when both rice and
wheat residues were added along with fertilizer N @ 120 kg N /ha.

Abstract Synthetic gypsum, a by-product of electricity generation, is used as a soil amendment to overcome water ponding, improve soil and water quality, improve field conditions to support farm equipment, and reduce the variability of crop yield in no-till fields by improving hydrology. Gypsum is a source of soluble calcium (Ca) that improves physical properties of the soil by promoting clay aggregation, thereby increasing water infiltration rates and movement through the soil profile. Undisturbed soil samples from Brookston and Celina soils in Ohio, USA were collected to a depth of 75 cm in agricultural fields treated with gypsum for 0, 4, and 12 years to determine changes in chemical and physical properties. Gypsum applications increased exchangeable Ca and Ca: Mg ratios, and promoted clay flocculation and improved soil structure. Mean weight diameter of aggregates increased with gypsum treatment at most depths in both soils. Micromorphological analysis showed variations in porosity (ɸ), pore size distribution, pore shape and aggregate size related to gypsum treatment, soil, and soil depth. There were no consistent responses to years of gypsum application. Gypsum treated soils had higher porosity than untreated soils in all depths

Tillage in combination with crop residue incorporation and application of fertilizer N at different rates are the main management options for the rice-wheat cropping system in Eastern India. A field experiment was conducted at IIT, Kharagpur to find out the impact of tillage, crop residue and rate of fertilizer N application on soil properties and yield of rice and wheat crops. The results of the experiment revealed application puddling increased the bulk density of soil measured after the harvest of rice or wheat crops. Puddling also decreased the saturated hydraulic conductivity, which in turn increased water retention of the soil and increased the yield of transplanted rainfed rice (TR). Yield of direct seeded rice (DR) grown in soil tilled with cultivator followed by disc harrow, was comparatively lesser than the grain yields of TR. The tillage treatment (cultivator followed by disc harrow) for wheat succeeding both TR and DR was same but yield of wheat crop succeeding DR was mo...