Effect of crop residue addition on soil organic carbon priming as influenced by temperature and soil properties

Priming of soil organic carbon (SOC) is a crucial factor in ecosystem carbon balance. Despite its increasing importance in the changing global climate, the extent of influence of temperature and soil properties on the priming effect remains unclear. Here, soil priming was investigated using 13C labeled wheat residues in two cultivated, subtropical (Vertisol) and semi-arid (Luvisol), soils of Australia at four incubation temperatures (13, 23, 33 and 43 °C). The priming effect was computed from respired CO2 and associated δ13C, which were measured periodically over the 52-day incubation period. Wheat residue addition resulted in greater priming effect in the Luvisol (1.17 to 2.37% of SOC) than the Vertisol (0.02 to 1.56% of SOC). The priming of SOC was the highest at 23 °C in the Luvisol, and at 43 °C in the Vertsiol, which indicates a variable positive priming effect of temperature in different soil types. Wheat residue addition significantly increased the temperature sensitivity (Q10) of SOC mineralization in the Vertisol at temperature ranges below 33 °C (i.e., 13–23 and 23–33 °C) and had no significant effect in the Luvisol. A negative correlation was observed between temperature and the Q10 values. Across soils, the Q10 of residue C was lower than SOC suggesting that soil C is more vulnerable to climatic warming. This work demonstrates that the magnitude of SOC priming by wheat residue and Q10 of SOC mineralization varied significantly with soil type (Luvsiol > Vertisol) and incubation conditions (temperature and time). Given the current trend towards increasing atmospheric temperatures, future studies should evaluate temperature effects on the priming of different pools of SOC induced by crop residue in different agro-ecosystems

Tillage and nutrient management influence net global warming potential and greenhouse gas intensity in soybean-wheat cropping system

207-214Conservation tillage has proven advantageous in improving soil health and productivity. However, the greenhouse gases (GHGs) emission and intensity from different conservation tillage and nutrient management systems under Indian conditions are less understood. Therefore, here, we compared the effect of tillage and nutrient management on GHGs emissions, net global warming potential (NGWP), and greenhouse gas intensity (GHGI) from a field experiment under five years in a soybean-wheat cropping system in the Vertisols. The tillage treatments comprised of reduced tillage (RT) and no tillage (NT). The three nutrient management treatments included application of 100% NPK (T1), 100% NPK + 1.0 Mg FYM-C ha-1 (T2), 100% NPK +2.0 Mg FYM-C ha-1 (T3). The results showed significantly higher SOC sequestration under NT (1388 kg ha-1 yr-1) followed byRT (1134 kg ha-1 yr-1) with application of FYM (2.0 Mg C ha-1) (T3) every year. Across tillage, integrated nutrient management(T2 and T3) lowered NGWP and GHGI compared to NPK (T1). The GHGI of NT system was less by 33% compared to RT. The results suggest that GHGs mitigation and sustained food production in the soybean-wheat system can be achieved in NT and RT with integrated use of organic and inorganic fertilizer as the major component of nutrient management

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Not AvailableThe state of Odisha is severely affected by water erosion induced land degradation due to its hilly and undulating terrain and unsustainable land management practices. Ensuring sustainable development of the state needs appropriate land use plan taking into account the heterogeneity in soil and land resources. In this study, the maximum permissible soil loss rates (‘T’ value) were computed for 159 mapping units of Odisha by integrating most sensitive soil indicators such as infiltration rate, bulk density, water stable aggregate, organic carbon and fertility status to assess soil quality governing soil resistibility to erosion. For each mapping unit, indicator soil attribute values were quantitatively expressed in 0 to 1 scale and an aggregate score was computed from the attribute scores and the corresponding weights. The results suggested a wide difference in the ‘T’ value among the regions and mapping units, with values varying from 2.5 to 12.5 Mg ha-1 yr-1. About 45% of total area of the state has a ‘T’ value of 10 Mg ha-1 yr-1 and 32% having ‘T’ value of 7.5 Mg ha-1 yr-1. In general, the southern, northern and western regions of the state have a lower ‘T’ values than the coastal plains and delta region. Major chunk of area under Eastern Ghats, Garhjat hills, Dandakaranya and Mahanadi basin has ‘T’ < 10.0 Mg ha-1 yr-1 and can’t afford to lose more than 7.5 Mg ha-1 yr-1 of soil. The information generated shall serve as a useful guide for devising differential conservation and resource use plans on the basis of soil resource potential.Not Availabl

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Not AvailableSoil is the largest reservoir of C in terrestrial ecosystem and any change in soil organic carbon (SOC) stocks is reflected in the soil–atmosphere CO2 exchange. Soil organic carbon is an integral component of soil organic matter (SOM) that plays an important role in maintaining and sustaining ecosystem functions and soil productivity. Understanding the dynamics of SOC is important to maintain SOC stocks in soil and to sustain crop yield. An accurate estimate of the change in SOC dynamics is also essential in the wake of fast-changing climate and global warming. The direct impact of climate change is on net primary productivity which is a key driver in SOC dynamics. This change in net primary productivity and soil management would alter SOC dynamics. Several researchers have attempted to simulate the SOC dynamics through building process-based SOC models at different scales like microsites, regional and global. Modelling the dynamics of SOC in the soil is complicated by the fact of numerous controls on SOC mineralization. The challenge lies in calibrating and validating these SOC models for Indian condition which has different soil types, vegetation, and climate. This chapter is aimed to discuss the potentials and limitations of using different SOC models in India with a brief on the importance of SOC and their controls.Not Availabl

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Not AvailableLand degradation due to water erosion is a major impediment for optimum land productivity in West Bengal (WB). Sustainable development of the state needs appropriate land-use planning taking into account the heterogeneity in soil and land resources. In this study, the maximum permissible soil loss rates (T values) were computed for 115 mapping units of WB by integrating the most sensitive soil indicators such as infiltration rate, bulk density, water stable aggregates, organic carbon and fertility status to assess soil quality governing soil resistibility to erosion. For each mapping unit, indicator soil attribute values were quantitatively expressed in the 0 to 1 scale and an aggregate score was computed from the attribute scores and the corresponding weights. The results suggested a wide difference in the T values among the regions and mapping units, with values ranging from 2.5 to 12.5 Mg ha–1 yr–1. In the state as a whole, about 88% of the area has ‘T’ value of 12.5 Mg ha–1 yr–1. The relatively plain lands in the Indo-Gangetic plain, coastal and delta plain and the Bengal basin have a higher soil loss tolerance of about 4.0 Mg ha–1 yr–1 than the hilly and undulating regions in the Eastern Himalaya and Eastern plateau regions. The information generated will serve as a useful guide for devising differential conservation and resource use plans on the basis of soil resource potential.Not Availabl

Effect of Reversal of Conservation Tillage on Soil Nutrient Availability and Crop Nutrient Uptake in Soybean in the Vertisols of Central India

Effect of conservation tillage on crop performance and soil properties has been studied extensively under different agro-climatic situations. However, the impact of reversal from conservation tillage to conventional tillage on crop growth and soil nutrient release is rarely addressed. Thus, this study was conducted by converting half of the eight years old conservation tillage experiment to the conventional one with a similar level of residue return to compare the effect on soil nutrient availability and nutrient uptake in soybean crops in the Vertisols of Central India. The conservation tillage treatments included no-tillage (NT) and reduced tillage (RT) with 100% NPK (T1), 100% NPK + farmyard manure (FYM) at 1.0 Mg-carbon (C)/ha (T2), and 100% NPK + FYM at 2.0 Mg-C/ha (T3). After eight years of the experiment, the RT and NT treatments were subjected to conventional tillage, and thus the tillage treatments were RT-CT, RT, NT, and NT-CT. After tillage reversal for three growing seasons, soybean yield and nutrient uptake (N, P, K) got significantly influenced by the tillage and nutrient management. Averaged across nutrient treatments, NT showed highest soil organic carbon (SOC) content (8.4 g/kg) in the surface 0&ndash;5 cm layer. However, at 5&ndash;15 cm depth, the SOC was greater in the RT-CT treatment by 14% over RT and by 5% in the NT-CT treatment over NT. The soil nutrient availability (N and P) was not significantly (p &gt; 0.05) affected by the interaction effect of tillage and nutrient on the surface soil layer (0&ndash;5 cm). Interaction effect of tillage and nutrient was significant on available P content at 5&ndash;15 cm soil depth. In contrast to N, soil available P relatively increased with reversal of tillage in both NT and RT. Tillage reversal (NT-CT, RT-CT) and RT had significantly higher available potassium than NT in 0&ndash;5 and 5&ndash;15 cm soil layers. Among the treatments, NT-CT-T3 showed significantly higher seed N (85.49 kg/ha), P (10.05 kg/ha), and K (24.51 kg/ha) uptake in soybean. The study indicates conventional tillage with residue returns and integrated nutrient management could be a feasible alternative to overcome the limitations of no-till farming in the deep black Vertisols of Central India

A 0.6 mW 1.6 dB Noise Figure Inductorless Shunt Feedback Wideband LNA With Gm Enhancement and Current Reuse in 65 nm CMOS

This paper presents the design of an inductorless low power differential Low Noise Amplier (LNA) for multi-standard radio applications between 0.2-3.2 GHz. Conventionally, the low power shunt-feedback based LNA noise performance suffers due to the low intrinsic gm of MOS transistors. A single stage differential shunt-feedback LNA which incorporates both, Gm boosting and current-reuse technique is proposed to overcome the noise performance degradation in low power designs. A detailed analysis of the conventional inductorless shunt-feedback based LNA along with the proposed technique is provided. It provides a good trade-off between different performance parameters after sizing and biasing optimization under ultra low power design constraint. The proposed technique is implemented in 65 nm CMOS technology and occupies an active area of 0.25 mm2. It exhibits a power gain of 13.5 dB with 1.6 dB NF while dissipating only 0.6 mW power

Tillage and nutrient management influence net global warming potential and greenhouse gas intensity in soybean-wheat cropping system

Conservation tillage has proven advantageous in improving soil health and productivity. However, the greenhouse gases (GHGs) emission and intensity from different conservation tillage and nutrient management systems under Indian conditions are less understood. Therefore, here, we compared the effect of tillage and nutrient management on GHGs emissions, net global warming potential (NGWP), and greenhouse gas intensity (GHGI) from a field experiment under five years in a soybean-wheat cropping system in the Vertisols. The tillage treatments comprised of reduced tillage (RT) and no tillage (NT). The three nutrient management treatments included application of 100% NPK (T1), 100% NPK + 1.0 Mg FYM-C ha-1 (T2), 100% NPK +2.0 Mg FYM-C ha-1 (T3). The results showed significantly higher SOC sequestration under NT (1388 kg ha-1 yr-1) followed byRT (1134 kg ha-1 yr-1) with application of FYM (2.0 Mg C ha-1) (T3) every year. Across tillage, integrated nutrient management(T2 and T3) lowered NGWP and GHGI compared to NPK (T1). The GHGI of NT system was less by 33% compared to RT. The results suggest that GHGs mitigation and sustained food production in the soybean-wheat system can be achieved in NT and RT with integrated use of organic and inorganic fertilizer as the major component of nutrient management