Can adoption of climate resilient management practices achieve carbon neutrality in traditional green revolution states of Punjab and Haryana?

Decreasing greenhouse gas (GHG) emissions and enhancing soil carbon (C) sequestration in cropland are necessary to achieve carbon neutrality at national scale. The major objective of this study is to quantify the GHG mitigation potential of adopted climate resilient (CR) practices in CR villages using Ex-ACT tool developed by Food and Agriculture Organization (FAO). Intensively cultivated area of Punjab and Haryana was selected for carrying out this study. In both the states, villages were selected by considering the climate for past 30 years. In the selected villages, a set of CR practices were implemented in annuals, perennials, irrigated rice, fertilizer use, land use change and livestock and quantified the GHG mitigation potential in these villages for next twenty years. The tool predicted that the CR practices adopted were successful in enhancing the overall sink (carbon balance) in all the study villages. The villages of Punjab had recorded higher mitigation potential as compared to the villages of Haryana. The overall sink potential in these villages ranged from -354 to -38309 Mg CO₂-eq. The change in sink potential varied from 3.16 to 112% with lowest in Radauri and highest in Badhauchhi kalan village. The sink potential got doubled in Badhauchhi kalan village due to stopping rice straw burning and increase in area under perennials by 25%. The source potential varied from 6.33 to -7.44% across the study villages. Even with the implementation of NICRA, there was increase in source by 5.58 and 6.33% in Killi Nihal Singh Wala and Radauri due to irrigated rice, land use change and livestock. Majorly, rice straw burning was seen in most of the study villages, yet, with proper residue management and adoption of CR practices (mainly intermittent flooding) in rice cultivation resulted in emissions reduction up to 5-26% with enhanced productivity up to 15-18%, which can be considered for scaling up. Fertilizer management reduced the emissions by average of 13% across the study villages. Farm gate emission intensity per ton of milk and rice recorded highest emission intensity compared to annuals and perennials suggesting strict implementation of CR practices in rice cultivation and livestock sector. Implementation and scaling up of CR practices could potentially reduce the emissions and make the village C negative in intensive rice-wheat production system.

Chlorophyll fluorescence induction kinetics and yield responses in rainfed crops with variable potassium nutrition in K deficient semi-arid alfisols

Optimum potassium (K) nutrition in semi-arid regions may help crop plants to overcome constraints in their growth and development such as moisture stress, leading to higher productivity of rainfed crops, thus judicious K management is essential. A study was conducted to evaluate the importance of K nutrition on physiological processes like photosynthesis through chlorophyll a fluorescence and chlorophyll fluorescence induction kinetics (OJIP) of rainfed crops viz., maize (Zea mays L.), pearl millet (Pennisetum glaucum), groundnut (Arachis hypogaea), sunflower (Helianthus annuus), castor (Ricinus communis L.) and cotton (Gossypium hirsutum) under water stress conditions by studying their growth attributes, water relations, yield, K uptake and use efficiency under varied K levels. Highest chlorophyll content was observed under K60 in maize and pearl millet. Narrow and wide Chl a:b ratio was observed in castor and groundnut respectively. The fluorescence yield decreased in the crops as K dosage increased, evidenced by increasing of all points (O, J, I and P) of the OJIP curves. The fluorescence transient curve for K60 was lower than K0 and K40 for all the crops. Potassium levels altered the fluorescence induction and impaired photosynthetic systems in all the crops studied. There was no distinct trend observed in leaf water potential of crops under study. Uptake of K was high in sunflower with increased rate of K application. Quantitatively, K uptake by castor crop was lesser compared to all other crops. Our results indicate that the yield reduction under low K was due to the low capacity of the crops to translocate K from non-photosynthetic organs such as stems and petioles to upper leaves and harvested organs and this in turn influenced the capacity of the crops to produce a high economic yield per unit of K taken up thus reducing utilization efficiency of K.

Soil carbon sequestration in rainfed production systems in the semiarid tropics of India

Severe soil organic carbon (SOC) depletion is a major constraint in rainfed agroecosystems in India because it directly influences soil quality, crop productivity and sustainability. The magnitude of soil organic, inorganic and total carbon stocks in the semi-arid bioclimate is estimated at 2.9, 1.9 and 4.8 Pg respectively. Sorghum, finger millet, pearl millet, maize, rice, groundnut, soybean, cotton, food legumes etc. are predominant crop production systems with a little, if any, recycling of organic matter. Data from the long term experiments on major rainfed production systems in India show that higher amount of crop residue C input (Mg/ha/y) return back to soil in soybean-safflower (3.37) system practiced in Vertisol region of central India. Long term addition of chemical fertilizer and organic amendments improved the SOC stock. For every Mg/ha increase in SOC stock in the root zone, there occurs an increase in grain yield (kg/ha) of 13, 101, 90, 170, 145, 18 and 160 for groundnut, finger millet, sorghum, pearl millet, soybean and rice, respectively. Long-term cropping without using any organic amendment and/or mineral fertilizers can severely deplete the SOC stock which is the highest in groundnut-finger millet system (0.92 Mg C/ha/y) in Alfisols. Some agroforestry systems also have a huge potential of C sequestration to the extent of 10Mg/ha/y in short rotation eucalyptus and Leucaena plantations. The critical level of C input requirements for maintaining SOC at the antecedent level ranges from 1.1 to 3.5 Mg C/ha/y and differs among soil type and production systems. National level policy interventions needed to promote sustainable use of soil and water resources include prohibiting residue burning, reducing deforestation, promoting integrated farming systems and facilitating payments for ecosystem services. A wide spread adoption of these measures can improve soil quality through increase in SOC sequestration and improvement in agronomic productivity of rainfed agroecosystems.