Conservation Agricultural Practices Impact on Soil Organic Carbon, Soil Aggregation and Greenhouse Gas Emission in a Vertisol

Conservation agriculture (CA), comprising of minimum soil disturbance and crop residue retention (>30%), with a diversified cropping system, has become increasingly popular around the world. It is recognized as a sustainable practice to improve soil health by augmenting key soil properties. However, scanty information exists about the effect of CA practices on soil organic carbon (SOC), aggregation and greenhouse gas emissions (GHG) in a vertisol. Thus, this study investigated the effect of CA practices on SOC, soil aggregation and GHG emission under soybean-wheat and maize-chickpea cropping systems in a vertisol in Central India. Treatment consisted of three different tillage practices, being conventional tillage (CT), reduced tillage (RT), and no tillage (NT) under four cropping systems viz., Soybean–Wheat, Soybean + Pigeon pea (2:1), Maize–Chickpea and Maize + Pigeon pea (1:1). Regardless of cropping system, the soil under NT and RT exhibited better aggregation (20.77 to 25.97% increase), and SOC (12.9 to 19.4% increase) compared to the CT practice in surface layers. The aggregate-associated C concentration increased with aggregate size, and it was highest with large macroaggregates and lowest with silt and clay fractions across different tillage and cropping systems. Higher SOC stock was recorded under NT (4.22 ± 0.133 Mg C/ha) compared to RT (3.84 ± 0.123 Mg C/ha) and CT (3.65 ± 0.04 Mg C/ha) practices at 0 to 5 cm depth. Thus, the adoption of CA practices reduced CO2 emissions, while also contributing to increases in SOC as well as improvement in soil structure

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Not AvailableIn recent years, conservation agriculture (CA) is increasingly being promoted among small-scale farmers in the tropics as well as subtropics. The myriad of research results generated from the adoption of CA ranges from significantly higher benefits than conventional farming to disappointing results. Although CA has been recommended by several researchers as a part of sustainable agriculture, there might be certain gaps and issues related to practicing CA in small-scale farms. Do the benefits from CA remain the same for small-scale farmers? How well does CA fit with agricultural, social, economic, and political contexts for small-scale farmers particularly in developing nations? One of the low adoption rates of CA in sub-Saharan Africa and South Asia is the lack of economic incentive and high machinery cost for small-scale farmers in which the process of conversion from conventional farming to CA is not profitable. There might be certain limitations in the potential for subsidizing farmers to adopt CA using payments for ecosystem services/carbon credit schemes. Therefore, the smallholding farmers with low risk-taking abilities are unsure of practicing CA in their farms despite proven economic benefits from CA in several parts of the world. In this regard, there is an urgent need to move ahead of the prescriptive approaches to provide sustainable soil and crop management options for small-scale farmers in the region. Therefore, this chapter will focus to answer the question: “Does CA work for small-scale farmers in developing countries?” or “Is it just the mindset of the people or the negative results of CA trials that led to low CA adoption in different parts of the world?”Not Availabl

Repression of a matrix metalloprotease gene by E1A correlates with its ability to bind to cell type-specific transcription factor AP-2.

Adenovirus E1A 243-amino acid protein can repress a variety of enhancer -linked viral and cellular promoters. This repression is presumed to be mediated by its interaction with and sequestration of p3OO, a transcriptional coactivator. Type IV 72-kDa collagenase is one of the matrix metalloproteases that has been implicated in differentiation, development, angiogenesis, and tumor metastasis. We show here that the cell type-specific transcription factor AP-2 is an important transcription factor for the activation of the type IV 72-kDa collagenase promoter and that adenovirus E1A 243-amino acid protein represses this promoter by targeting AP-2. Glutathione S-transferase-affinity chromatography studies show that the E1A protein interacts with the DNA binding/dimerization region of AP-2 and that the N-terminal amino acids of E1A protein are required for this interaction. Further, E1A deletion mutants which do not bind to p3OO can repress this collagenase promoter as efficiently as the wildtype E1A protein. Because the AP-2 element is present in a variety of viral and cellular enhancers which are repressed by E1A, these studies suggest that E1A protein can repress cellular and viral promoter/enhancers by forming a complex with cellular transcription factors and that this repression mechanism may be independent of its interaction with p3OO

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Not AvailableConservation agriculture (CA) is considered a sustainable practice with the potential to maintain or increase crop productivity and improve environmental quality and ecosystem services. It typically improves soil quality and water conservation; however, its effect on crop productivity is highly variable and dependent on local conditions/management. Crop residue retention plays a crucial role in CA and can help to improve overall soil health and ultimately crop productivity and sustainability. However, weed control, herbicide resistance, and weed shift under residue retained fields is a major challenge. Moreover, CA can increase water infiltration and reduce soil loss and runoff. This reduces the surface transport of nitrate and phosphorus from agricultural fields and the eutrophication of water bodies, although leaching of nitrate to groundwater can potentially increase. In addition, CA has been proposed as one of the components in climate-smart agriculture, owing to its reduced period to seed/plant next crop, reduced soil disturbance and low consumption of fossil fuels. Therefore, compared to the conventional intensive tillage, CA has a greater potential for soil C sequestration, favors higher soil biodiversity, lowers greenhouse gas emission, and can assist in mitigating climate change. However, not all experiments report a positive impact. The understanding and decoding the site-specific complexities of CA system is important and requires a multidisciplinary approachNot Availabl

Soil Inorganic Carbon as a Potential Sink in Carbon Storage in Dryland Soils—A Review

Soil organic carbon (SOC) pool has been extensively studied in the carbon (C) cycling of terrestrial ecosystems. In dryland regions, however, soil inorganic carbon (SIC) has received increasing attention due to the high accumulation of SIC in arid soils contributed by its high temperature, low soil moisture, less vegetation, high salinity, and poor microbial activities. SIC storage in dryland soils is a complex process comprising multiple interactions of several factors such as climate, land use types, farm management practices, irrigation, inherent soil properties, soil biotic factors, etc. In addition, soil C studies in deeper layers of drylands have opened-up several study aspects on SIC storage. This review explains the mechanisms of SIC formation in dryland soils and critically discusses the SIC content in arid and semi-arid soils as compared to SOC. It also addresses the complex relationship between SIC and SOC in dryland soils. This review gives an overview of how climate change and anthropogenic management of soil might affect the SIC storage in dryland soils. Dryland soils could be an efficient sink in C sequestration through the formation of secondary carbonates. The review highlights the importance of an in-depth understanding of the C cycle in arid soils and emphasizes that SIC dynamics must be looked into broader perspective vis-à-vis C sequestration and climate change mitigation

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Not AvailableEvaluation of 100 Indian Musa accessions (IMA) for nine elements in their fresh fruit pulp (FFP) revealed genetic variability of 4.7-fold for K & Mg to 111.1-fold for Ca but, only with either highly or moderately positively skewed distribution. The descending order of mineral concentrations (MC) was K > Ca > Na > Mg > Fe > Mn > B > P > Zn. 100 g FFP contributes fairly about 5 (Fe) to 10% (Mn, Ca & Mg) of daily mineral requirement of Indians. Calcium (97%) and Fe (96%) showed the highest heritability while Zn exhibited lowest (85%). Significantly positive correlation was observed for all minerals. Magnesium had maximum direct effect on Fe content followed by Mn, Zn and Na in path analysis. Both principal component analysis and cluster analysis failed to group the IMA according to their ploidy/genome/subgroups. Twenty commercial cultivars were placed in top 10 positions based on their MC. Besides Ca and Mg, IMA were richer for all micronutrients than the world’s Musa gene-pool.Not Availabl

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Not AvailableVertisols constitute one of the unique soil orders, with distinct characteristics including self-mulching, swelling and shrinking, cracking, and pothole formation; and excessive surface runoff and soil erosion during high rainfall. Cracks are among distinct features and are used as defining criteria of Vertisols in Soil Taxonomy. The process of cracking is a significant researchable issue in soil science with regards to the occurrence, formation, management, and modeling. Management of Vertisols is a challenging task because of specific physical constraints such as narrow workable range of soil moisture, peculiar consistency of sticky when wet and very hard when dry, and cracking. The cracking pattern is affected by a variety of factors including clay content, soil moisture, tillage practices, cropping system, and land use. In addition, cracking is also affected by type and amount of clay and the moisture regime. Cracks can have both positive and negative influence on the soil–plant system. Soil cracks provide a passage for quick water entry into the deeper layer of soil profile in the rainy season, in turn reducing risks of soil erosion and enhancing the soil moisture reserves. On the other hand, slumping surface soils through cracks results in formation of potholes which exacerbate risks of ground water pollution. Cracks can aggravate losses by evaporation of irrigation- or rain water from the greater evaporating surface area during the postirrigation/rainy season. Increase in evaporative loss has implications to scheduling of irrigation and the quantity of water application. Cracks are also important to the movement of water down the soil profile following the prolonged/extended dry season, but are also a cause of extrawater losses through evaporation from the cracks’ surfaces. Despite their significance, scientific and practical knowledge about crack management in Vertisols is scanty. Cracking patterns in soil can be modified by tillage practices, organic amendments, and crop residue management. Therefore, suitable land management practices include measures for conserving the ground water such as permanent broad bed and furrow, and ridge-furrow systems used in conjunction with the application of organic manures and amendments and conservation tillage system. Such measures can decrease the formation of wide cracks, reduce loss of water through evaporation in semiarid environment, and improve soil health. This chapter describes occurrence, formation, characterization, and management of cracks and potholes for sustaining soil health and enhancing crop productivity on Vertisols.Not Availabl