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

Conservation tillage and manure effect on soil aggregation, yield and energy requirement for wheat (Triticum aestivum) in vertisols

Conservation tillage is gaining significant economic and environmental importance under changing climatic conditions. Hence this study was carried out to assess interactive effect of conservation tillage and manure treatments on soil aggregation, crop performance and energy requirement for wheat (Triticum aestivum L.) crop under vertisols of central India. The experiment was taken in a split plot design for four consecutive cropping seasons since 2008, with two tillage treatments, no tillage (NT) and reduced tillage (RT) in the main plot, and seven manure treatments in the sub plots. The effects were compared to farmer's practice, i.e. conventional tillage (CT). The seven manure treatments included application of FYM at the rate of 0, 0.5, 1.0 and 2.0 Mg C/ha, applied every year and 2.5, 5.0 and 10.0 Mg C/ha, applied at initiation of experiment. After four years of experiment, the mean weight diameter of soil aggregates was 1.4 and 1.2 times higher under NT and RT, respectively, as compared to CT. Averaged over manure treatments, the grain yield was higher by 1.17 and 0.59 Mg/ha in NT and RT, respectively, than the CT. The energy requirement was 4.68 and 2.32 times higher under CT, as compared to NT and RT systems. Also, the cost of production of wheat was 40.62% and 21.12% higher in CT as compared to NT and RT, respectively, resulting in saving of Rupees 7 800 and Rupees 4 725/ha/year in the two conservation tillage systems

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

Not Available

Not AvailableAgriculture sector is a potential contributor to the total green house gas (GHG) emission with a share of about 24 % (IPCC, AR5 to be released) of the total anthropogenic emission, and a growing global population means that agricultural production will remain high if food demands are to be met. At the same time, there is a huge carbon sink potential in this sector including land use, land-use change, and forestry sector. For over four decades, evidence has been growing that the accumulation of GHGs in the upper atmosphere is leading to changes in climate, particularly increases in temperature. Average global surface temperature increased by 0.6 ± 0.2 °C over the twentieth century and is projected to rise by 0.3–2.5 °C in the next 50 years and 1.4–5.8 °C in the next century (IPCC, Climate change: synthesis report; summary for policymakers. Available: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf, 2007). In the recent report of IPCC AR5 (yet to be released), it has been observed that warming will continue beyond 2100 under all representative concentration pathways (RCP) scenarios except RCP 2.6. Temperature increase is likely to exceed 1.5 °C relative to 1850–1900 for all RCP scenarios except RCP 2.6. It is likely to exceed 2 °C for RCP 6.0 and RCP 8.5 (Pachauri, Conclusions of the IPCC working group I fifth assessment report, AR4, SREX and SRREN, Warsaw, 11 November 2013). Agriculture is a potential source and sink to GHGs in the atmosphere. It is a source for three primary GHGs: CO2, N2O, and CH4 and sink for atmospheric CO2. The two broad anthropogenic sources of GHG emission from agriculture are the energy use in agriculture (manufacture and use of agricultural inputs and farm machinery) and the management of agricultural land. Mitigation methods to reduce emissions from this sector are thus required, along with identification and quantification of emission sources, so that the agricultural community can act and measure its progress. This chapter focuses on different sources of GHG emission from agriculture sector and their key mitigation strategiesNot Availabl

Not Available

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

Not Available

Not AvailableThis paper investigates the effects of selected conservation tillage systems compared with conventional tillage after six cropping seasons on soil aggregation, crack parameters and the net loss of water through bypass flow in the Vertisols of central India. The experiment on soybean-wheat cropping system was initiated with soybean crop during kharif 2008 with three tillage treatments namely, (1) no-tillage (NT), (2) reduced tillage (RT) and (3) conventional tillage (CT). After six cropping seasons, the effect of tillage treatments was significant on soil aggregation and crack parameters. The mean weight diameter (MWD) and water stable aggregates (WSA) were significantly higher under NT than CT in the 30 cm soil depth. In the 0–5 cm soil depth, the MWD under CT was 0.59 mm compared to 0.87 mm under NT. However, the conservation tillage practices showed a higher crack width and crack volume and thus caused greater loss of water through bypass flow compared with conventional tillage. The data showed that 43–68% of water applied was lost through bypass flow under NT compared to 26–43% under RT and the least, 20–23% under CT, when computed from below 60 cm soil depth. Thus, the trade-offs, between benefits of conservation tillage practices and the higher loss of water through bypass flow should be taken into account while promoting substitution for conventional tillage in Vertisols of central India.Not Availabl

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

Not Available

Not AvailableThe salt-affected soils cover vast area in more than 100 countries and increasingly decrease the arable land. It may lead to the global food insecurity that is needed to be solved urgently. Concurrently, these degraded areas are suitable for inland saline aquaculture on the conditions of improvement in sediment characteristics. In this connection, an experiment was conducted for 60 days to study changes in physicochemical properties of inland saline aquaculture pond sediments through biochar application. The biochar prepared from dried sugarcane bagasse at 500°C with 33% biomass recovery was characterized for its physicochemical properties and applied over surface and by mixing with the sediment. There was a significant (p < .05) increase in organic carbon (3.82%), available-P (2.13%), available-K (18%), Ca (5.62%), Mg (14%) and water-holding capacity (1.8 times), and decrease in pH (0.41 unit), EC (17%) and bulk density (7%) when biochar (18 t/ha) was mixed with sediment (T2 treatment), whereas increase and decrease in CEC (59%) and available-N (1.01 times), respectively, when biochar (18 t/ha) were applied over sediment surface (T4 treatment). Thus, mixing of sugarcane bagasse biochar with sediment at 18 t/ha is recommended for the improvement of soil characteristics in saline soils for aquaculture through this study. Furthermore, the SEM and FT-IR analysis of treatments showed that sediment aggregation and functional group characteristics improved over a short period of incubation along with microbial biomass.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