Ashim Datta

Assessing soil properties and nutrient availability under conservation agriculture practices in a reclaimed sodic soil in cereal-based systems of North-West India

ABSTRACT Soil quality degradation associated with resources scarcity is the major concern for the sustainability of conventional rice-wheat system in South Asia. Replacement of conventional management practices with conservation agriculture (CA) is required to improve soil quality. A field experiment was conducted to assess the effect of CA on soil physical (bulk density, penetration resistance, infiltration) and chemical (N, P, K, S, micronutrients) properties after 4 years in North-West India. There were four scenarios (Sc) namely conventional rice-wheat cropping system (Sc1); partial CA-based rice-wheat-mungbean system (RWMS) (Sc2); CA-based RWMS (Sc3); and CA-based maize-wheat-mungbean (Sc4) system. Sc2 (1.52 Mg m−3) showed significantly lower soil bulk density (BD). In Sc3 and Sc4, soil penetration resistance (SPR) was reduced and infiltration was improved compared to Sc1. Soil organic C was significantly higher in Sc4 than Sc1. Available N was 33% and 68% higher at 0–15 cm depth in Sc3 and Sc4, respectively, than Sc1. DTPA extractable Zn and Mn were significantly higher under Sc3 and Sc4 compared to Sc1. Omission study showed 30% saving in N and 50% in K in wheat after four years. Therefore, CA improved soil properties and nutrient availability and have potential to reduce external fertilizer inputs in long run.

Bioremediation of Heavy Metals by Microbes

Heavy metals are naturally present in the soil, but higher concentration of these elements is harmful to plants, animals, and humans. Prolonged exposure of such heavy metals can have deleterious health effects on human life. Bioremediation of these heavy metals like As, Cd, Cr, Hg, Ni, Hg, and Zn can be done by either plants or microorganisms or by the combination of two. In this chapter emphasis has been given to its microbial methods. There are certain disadvantages associated with physicochemical methods of remediation; thus bioremediation is arising as alternative to these methods. It is an environment friendly approach because it is achieved via natural processes. In this chapter efforts have been made to give brief introduction of available physicochemical and biological methods of heavy metal remediation. Bioremediation by bacteria and fungi is discussed in detail.

Chapter 11 – Dynamics of Carbon and Nitrogen in Agricultural Soils: Role of Organic and Inorganic Sources

Abstract Soil contains huge quantities of organic and inorganic carbon and nitrogen, thereby it acts as both a source and sink. In atmosphere, CO2 concentration has already crossed 400xa0ppm mark, and it is foreseen to increase in the future. This necessitates the identification of strategies that not only improve soil quality, but also serve many ecosystem functions through sequestering C in soil. Organic and inorganic substances, such as farmyard manure, composts, fertilizers, are normally applied to soil as carbon and nitrogen sources. These materials undergo many complex transformation processes in soil, after which the nitrogen and other nutrients become available to plants. The dynamics of C and N in soil upon the application of organic/inorganic sources are very important to management practices. Therefore in this chapter, an attempt has been made to summarize the dynamics of C and N in soil upon application of organic and inorganic sources.

Effect of Crop Management Practices on Crop Growth, Productivity and Profitability of Rice–Wheat System in Western Indo-Gangetic Plains

An experiment was conducted with three managements varied in tillage, crop establishments, residue, fertilizer, water to evaluate crop behaviour, irrigation water use, crop productivity and profitability of crops in an individual and in system mode. Three management systems were conventional system [TPR (transplanted rice)–CTW (conventional-till wheat)], partial CA [TPR–ZTW (zero–till wheat)] and full CA [ZTDSR (ZT direct seeded rice)–ZTW]. Rice plant growth (shoot and root) behaves similarly in CT and ZT based systems up to 40xa0days after sowing and after that TPR–ZTW recorded higher growth followed by TPR–CTW and lowest with ZTDSR. However, reverse trend in growth was observed with wheat in order of ZTDSR–ZTWu2009>u2009TPR–ZTWu2009>u2009TPR–CTW. Lower NDVI values were observed with ZTDSR and higher values with TPR throughout the crop season. Full CA based wheat recorded higher NDVI values than other management systems during the crop growth period. Higher wheat yield attributing character was recorded with ZTDSR–ZTW and lowest with farmer’s practices (TPR–CTW). On 2-years mean basis, ZTDSR–ZTW system produced similar crop yields to TPR–ZTW and TPR–CTW with 28% less irrigation water and 29% higher returns compared to TPR–CTW. However, TPR–ZTW improved system productivity and net returns by 8 and 37% respectively, compared to TPR–CTW while saving of 14% irrigation water. ZTDSR recorded a yield loss of 10%; while wheat registered a yield gain of 21% with ZTDSR–ZTW. CA based management practices slowed down the DSR crop growth and yield but increased same for wheat crop which is ultimately helpful in sustaining productivity and profitability of rice–wheat system (RWS) in North West India.

Production (via N-fertilization) and correction (by liming) of acidity in soils contribute a huge efflux of CO2 to atmosphere: Real or arbitrary?

In a recent article, Zamanian etxa0al. (2018) made an interesting assessment for CO2 efflux to atmosphere from inorganic carbon in soils on N-fertilization induced acidity (7.48 × 1012 g CO2 C/year) and also from liming of acid soils (273 × 1012 g CO2 C/year) using global database of soil CaCO3 stock, acid soil coverage, N-fertilizer use and associated quantity of protons produced etc. We have the following few non-convergent points of views on the issues.Firstly, stoichiometry of protonation (H+ ) in soils out of N-fertilization through urea, and other sources is known and the resultant annual changes in soil pH are also reported by many, including those who used long-term experiments (Stewart etxa0al., 2015; Ghimire etxa0al., 2017). This article is protected by copyright. All rights reserved.

Diversity of Wild Edible Mushrooms in Indian Subcontinent and Its Neighboring Countries

Mushrooms are cosmopolitan heterotrophic organisms that are quite specific in their nutritional and ecological requirements. They are among the most relished food commodities among a number of nonconventional foodstuffs primarily because of their unique flavor and texture. Wild edible mushrooms have been collected and consumed by people since thousands of years. Mushrooms have been exploited commercially the world over. In India due to its diverse climatic conditions, many types of mushrooms are found in the wild. The knowledge of their historical uses as food, medicine, a source of income, and for small-scale businesses and the sociological impacts (myth, culture, and spirituality) are apparently threatened due to slow ethnomycology-research drive.