Pabitra Kumar Mani

Effect of organic amendments on rice yield trend, phosphorus use efficiency, uptake, and apparent balance in soil under long-term rice-wheat rotation

ABSTRACT The experiment was conducted in a 22nd cycle of rice-wheat rotation established in the eastern India with a randomized block designed with various combinations of inorganic and organic sources of nutrients like farm yard manure (FYM), paddy straw (PS), and green manure in rice crop only. Application of nitrogen, phosphorus, and potassium (NPK) and its combination with FYM, PS, and green manuring increased the grain yield of rice significantly. Rice yield declined only in control plots (−0.003 t ha−1 year−1), whereas positive yield trend was maintained in all the treatments. All organically amended plots showed a better uptake as well as use efficiencies of applied phosphorus (P) inputs over control. The apparent P balance showed positive value in control treatment over the years ranging from −4.8 to 24.8 kg ha−1 year−1. The positive yield trend of rice was maintained due to buildup of P from various organic inputs.

Organic Amendments Influence on Soil Biological Indices and Yield in Rice-Based Cropping System in Coastal Sundarbans of India

ABSTRACT The present investigation was carried out in coastal Sundarbans of India to study the effects of farm yard manure, green leaf manure, and vermicompost on biological attributes of soils and yield in rice–tomato, rice–sunflower, and rice–chili cropping system over conventional farmer’s practices (control) by a strip-plot technique for the two consecutive years. The partial substitution of inorganic fertilizers through organics significantly increased the yield of various cropping systems. The use of organic materials significantly improved microbial biomass carbon, fluorescein diacetate hydrolyzing activities, dehydrogenase, and β-glucosidase activity over control, which varied in the tune of 51.6%, 67.4%, 50%, and 62.7%, respectively, due to variation in electrical conductivity (EC) of these soils. The improved soil microbial biomass and enzyme activities act as key driving factor for organic matter decomposition and nutrient transformation in organically amended soils which lead to better yield under such cropping sequences.

Agri-nanotechniques for Plant Availability of Nutrients

Nanotechnology has opened up a number of scopes for novel applications in the field of agricultural industries, because of several unique physicochemical properties of nanoparticles (NPs), i.e., high surface area, high reactivity, tunable pore size, and particle morphology. Nanoparticles may be treated as “magic bullets,” containing nanopesticides, nanofertilizers, etc., which will trigger specific cellular organelles in the plant to release their contents. So far, little information is available on the behavior of nanofertilzers in soil system, as well as utilization of nanoparticles for smart delivery of fertilizers. Still NPs have already shown promise for their potential utility in crop production in the form of nanofertilizers, nanopesticide, nanoherbicides around the world. The present chapter highlights the key role of nanoparticles in soil systems, their characterization, behavior, mobility, and effective means for the smart delivery of fertilizers that has a strong bearing on the growth and yield of plants. Nano-based slow-release or controlled-release (CR) fertilizers have the potential to increase the efficiency of nutrient uptake. In this chapter, utilization of nanoparticles for delivery of fertilizers in an agricultural production system for the sustainable environment has been described.

Determining critical limit of boron in soil for wheat (Triticum aestivum L.)

Abstract Critical values of boron (B) for wheat nutrition in soil and plant were determined through a pot experiment with twenty-one surface soils of Alluvial flood plain and Red-latertic belt comprising three major soil orders (Entisols, Alfisols, Inceptisols) with four levels of boron. Application of boron significantly increased the dry matter yield as well as uptake of B by plants. Critical concentration of hot calcium chloride (CaCl2) extractable B in soil for wheat was found to be 0.53 mg kg−1. The critical plant B concentration varied with growth stages and values were 7.4 mg kg−1 at panicle initiation and 4.18 mg kg−1 at maturity, respectively. The findings of this investigation also recommend the application of 2 kg B−1 ha−1 for ensuring B sufficiency to wheat in Indo-gangetic alluvial and Red-Lateritic soils.

Influence of organic amendments on soil physical attributes and aggregate associated phosphorus under long-term rice-wheat cropping

Abstract The quantification of phosphorus (P) in bulk soil and P distribution in different size fractions of water-stable aggregates (WSAs) are important for assessing potential P loss through runoff. We evaluated available and total P distribution within WSAs of a sitty clay to clay soil in a long-term fertility experiment of a rice-wheat cropping system in India. Surface soil samples were collected from seven plots amended with NPK fertilizers in combination with or without organic amendments, farmyard manure (FYM), green manure (GM), and paddy straw (PS). The plot with no NPK fertilizers or organic amendments was set as a control. The soil samples were separated by wet sieving into four soil aggregate size fractions: large macroaggregates (> 2.0 mm), small macroaggregates (0.25–2.0 mm), fine microaggregates (0.05–0.25 mm), and a silt + clay-sized fraction ( small macroaggregates > fine microaggregates > large macroaggregates. Within a size class, aggregate-associated available and total P contents in the organically amended soil were in the following order: FYM > PS ≥ GM. The available P content of the microaggregates ( 0.25 mm), and the total P content of the microaggregates was 4- to 5-times higher than that of the macroaggregates. Cultivation without organic amendments resulted in more microaggregates that could be checked by the application of organic amendments such as FYM and GM, which increased the proportion of water-stable macroaggregates by consolidating microaggregates into macroaggregates.

Assessing suitability of different extractants for determining available boron in soil

ABSTRACT In the present study, the extractability of available Boron (B) by different extractants was tested in relation to soil properties. Soil samples from different parts of Indo-Gangetic flood plains of West Bengal were collected and available B extracted with various extractant viz. hot calcium chloride (CaCl2) (HCC), Potassium di-hydrogen phosphate (PDP), tartaric acid (TA) and MCC. Plant availability of B was assessed by growing wheat (Triticum aestivum L.cv.K-1006) in such soils through pot experiments. HCC showed the highest available B content as well as highest correlation coefficient value with all plant growth parameters and soil properties. The B extracting efficiency of the tested extractants was found in the order of HCC > PDP > TA > MCC. Results showed that dry matter yield, plant B concentration and uptake was increased significantly after application of Borax. Linear Correlations, Multiple regression analysis using Mallows Cp statistics proved HCC to be the best extractant for estimating available B in experimental soils.