Dhaneshwar Padhan

Liming Influences Forms of Acidity in Soils Belonging to Different Orders under Subtropical India

A pot experiment was conducted to study the influence of liming on changes in different forms of acidity in relation to soil properties. Thirty-six surface (0–15 cm deep) soil samples were collected from different soil orders, namely Entisols, Inceptisols, Alfisols, and Entisols of coastal saline zone of West Bengal, India, and incubated for 21 days with three doses of lime [i.e., no lime (L0), half lime (L1/2), and full lime (L1)]. Results of analysis of soil showed that there were significant increases in pH in water (pHw) and pH in 0.02 M calcium chloride (CaCl2) (pHCa) (1.3 and 1.5 units) and decrease in total acidity, hydrolytic acidity, exchange acidity, electrostatically bound aluminium (EBAl3+), and electrostatically bound hydrogen (EBH+) upon liming being from 1.53 to 0.57, 1.40 to 0.54, 0.13 to 0.03, 0.08 to 0.01, and 0.06 to 0.02 cmol (p+) kg−1, respectively. The decrease in values of all the forms of acidity was greater in L1 than in L1/2 treatment under Entisols of the terai zone, followed by Entisols of coastal saline zone, Inceptisols, and Alfisols. The forms of acidity showed significant positive correlation with each other but negative correlation with pHw and pHCa, except for EBH+.

Microbial Transformation of Sulphur: An Approach to Combat the Sulphur Deficiencies in Agricultural Soils

Sulphur, an essential component for plant as well as animals, is present in soils in both organic and inorganic forms, with organic form particularly sulphate esters and carbon-bonded sulphur contributing ~75–90% of the total. The major sources of sulphur in soils are sulphur-containing minerals, plant and elemental residue and external addition including atmospheric deposition. Sulphur deficiency in plants results in poor nitrogen metabolism thus protein biosynthesis, chlorosis, low oil percentage and ultimately low yield. The conversion of organic sulphur in organic matter to inorganic form and vice versa is dominantly a microbiological process. In well-aerated soil, organic sulphur is mineralized to sulphate and taken up by plants. Concurrently inorganic sulphur is immobilized to organic form and incorporated in microbial tissue. The rate of these processes obviously depends on soil reaction, temperature, moisture and addition of crop residue and many other factors that ultimately affect the activity of microorganism. Several enzymes in soil, viz. arylsulphatase, play a major role in sulphur mineralization process though very little information is available till now towards the pathway of decomposition. In addition to this process, inorganic sulphur in soil undergoes various oxidation and reduction process, modulated by microorganisms. Various reduced inorganic sulphur compounds are oxidized by a group of bacteria in suitable condition and utilize the energy. The wide range of stable redox states and their interconversion affect sulphur cycle, fate of applied fertilizer and ultimately its availability to plants and microbes. In this chapter we reviewed the sulphur cycle and its transformation by various microbial processes.

Effect of Long Term Fertilization on Soil K Dynamics and Uptake by Hybrid Maize in an Irrigated Inceptisol under Intensive Cropping

Potassium (K) is the third most important essential major plant nutrient with numerous functions. It plays a vital role in enzyme activation, osmotic regulation, energy relations, translocation of photosynthates, protein and starch synthesis there by underpinning agronomic productivity and sustainability (Mengel, 1985). Soil K exists in four different forms viz., water soluble-K, most frequently available form to plants; exchangeable-K, held by negative charges on soil colloids and is readily available to plants; non-exchangeable or fixed-K, which is trapped between layers of expanding lattice International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 6 Number 10 (2017) pp. 1049-1061 Journal homepage: http://www.ijcmas.com

DTPA-Extractable Zinc in Rice Soils and Its Availability to Rice

Zinc (Zn) deficiency is a fairly wide spread agronomic constraint in many of the world rice production regions. Information on soil Zn distribution is essential for understanding its chemical reactions and bioavailability. In this backdrop, we tried to find out the relationship between physicchemical properties and DTPA-extractable Zn (available Zn) content of rice soils. For this eighty four (84) surface soil samples (0-20cm) were collected from three villages (viz. Saharapali, Nuagarh and Adgaon) of Bargarh district under the Hirakud Command Area of Odisha. Analytical observations revealed that the soils were slightly acidic in reaction with moderately high content of soil organic carbon. Considering the critical limit of available Zn in soils to be 0.6 mg kg-1, all soils of the study area were found to be well supplied with DTPA-extractable Zn. Soil organic carbon (SOC) content maintained positive and significant correlation with available zinc content in soils. However, soil pH showed significant but negative correlation with available zinc content of soils.