Molybdenum Status in Selected Benchmark Soils of India and Its Relationship with Soil Properties

摘要

Molybdenum (Mo) is a metallic transition element in the earth’s crust, usually in low concentrations (<3 mg kg '). However, the concentration and form of Mo in rocks and soils vary according to particular origins and conditions of formations. Molybdenum having released from crystal lattices by weathering, is found in well aerated agricultural soils (pH in water > 5.0) mainly as molybdate ions, Mo04^' (Lindsay 1972). This predominance of the anionic form makes Mo unique among metallic plant nutrients. Molybdenum exists in soil solution as oxidizing (Mo'’^ predominant) or reducing (Mo'*^) conditions (Manheim and Landergren 1978). Molybdenum is required for growth of most biological organisms including plants. Some soil types are more vulnerable to Mo deficiency than others. A deficiency is much more likely in soils with a pH of less than 5.8 (Yoshitaka 2013). Information regarding the availability of Mo in Indian soils is quite meager, very sporadic and non-systematic due to cumbersome time-consuming method of its analysis in soils and plants. Systematic delineation of sufficiency and deficiency areas for Mo is not adequately dealt with. Very few research workers reported on Mo status in soils. However, in the present era of sophisticated agriculture, in view of sustainable crop production, it is being strongly felt that deficiency and sufficiency of Mo must be assessed for different crops under different locations. This valuable knowledge on status on Mo for different soil types, regions as wellas for country as a whole is essential to formulate the strategies for amelioration of such deficiency timely and more precisely. Moreover, the vital roles Mo plays in plant nutrition are of such fundamental importance that it has become imperative to assess the status of the element in soils. In this investigation, soil samples have been collected from different established benchmark sites, so that the data can be used as a reference by different users and farmers. Generally, Mo is present in deficient or in marginal level in acid to nearly alkaline soils. Those soil types cover a wide area of the country. So, from this investigation, a systematic and informative database of Mo sufficiency or deficiency has been generated which is essential to formulate the strategies for amelioration of such deficiency timely and more precisely. The specific purpose of this study was to delineate the available Mo status in different benchmark soils of India and to find out the relationship between available Mo anddifferent soil properties.