Shikha

Front Line Demonstrations were conducted to evaluate the effect of zinc sulphate on the yield of rice varieties VL-85 and Pusa Basmati-1509 (PB-1509) under zinc-deficient areas of hills of Uttarakhand in around 1 hectare (ha) area at each village of Nala and Dadoor among 20 farmers by Krishi Vigyan Kendra (KVK), Tehri Garhwal during the year 2017–18. A total of 40 demonstrations were conducted in 2 ha. The results revealed that with the application of zinc sulphate @ 25 kg ha⁻¹ on VL-85, the grain yield obtained was 29.50 q ha⁻¹ while the grain yield under the traditional method (farmer's practice) was 22.00 q ha⁻¹ resulting in a 34.09% increase in yield. However, the yield of Pusa Basmati-1509 was considerably higher in the demonstrated practice (DP), i.e., 32.8 q ha⁻¹ than in the farmer's practice (FP), i.e., 23.5 q ha⁻¹ resulting in a 39.57% increment in yield. Hence, it was evident that the yield obtained was more with the use of zinc sulphate in highyielding varieties (HYVs) than with the farmer's practice. Similarly, the Benefit-Cost (B:C) ratio of VL-85 and PB1509 with the use of zinc sulphate in DP was 2.03 and 2.18, respectively whereas in FP, B:C ratio was 1.58 and 1.45, respectively. Hence, it was observed that the demonstration of zinc sulphate in local variety and HYVs of rice in zinc-deficient areas was found better in terms of increasing the production of rice crops under nutrientdeficient areas and the farmers of that region accepted the demonstrated technology. Hence, it can be concluded that the cultivation of Pusa Basmati-1509 with the application of zinc sulphate @ 25 kg ha⁻¹ can be recommended for zinc-deficient hilly areas of Uttarakhand.

Mineralization of carbon (C) is a burning issue that is regulated by soil attributes. It has direct impacts on crop productivity and quantification of organic residue addition in soil. For better understanding and achievement of potential tillage benefits, a comprehensive scientific understanding of C mineralization is very important. Therefore, a laboratory incubation experiment was conducted to investigate the C mineralization rates and kinetics of crop residues (rice and maize) when applied on the surface (as zero-tillage, ZT) and incorporation (as conventional tillage, CT) in four different soil types (S1 and S2 of Entisol; S3 and S4 of Inceptisols) of West Bengal state, India. Results showed that after 7 days of incubation, there was a rapid phase of decrease in CO₂-C fluxes. It continued up to day 14 followed by a sluggish nature of CO₂ emission up to day-42, and after that almost levelling off in all subsequent periods up to the end of 126 days of incubation. There was a progressive release of cumulative total C from the soils with an increase in time till the last day of incubation. For every 10% increase in C loss, there was about 0.376 mg/g C mineralization from the applied residue C. It was evident from the kinetic models that C mineralization from the residues followed the exponential model: C = Co(1 − e^−kt). Similar rate constant (k) values were recorded in both placement methods, but the rate of maximum potential mineralizable (C₀k) residue C was higher under residue incorporation treatments for both rice and maize residue. However, the rice and maize residues showed almost similar amounts of C mineralized over time when applied on the surface. The future prediction analysis using the equation C = Co(1 − e^−kt) suggested that the residues incorporated into the soil releases a maximum C irrespective of residue type. We conclude that the residues when incorporated into the soil significantly increases the C footprints through maximum C mineralization; leaving the crop residue on the soil surface reduces the C footprints which helps in achieving sustainability from an environmental perspective.