Current Science

S. K. Sanyal ¹, B. S. Dwivedi ², V. K. Singh ³, K. Majumdar ⁴, S. C. Datta ², S. K. Pattanayak ⁵, K. Annapurna ²

Affiliations
1 Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, Nadia 741 252, IN
2 Indian Agricultural Research Institute, New Delhi 110 012, IN
3 Farming Systems Research, Modipuram, Meerut 250 110, IN
4 International Plant Nutrition Institute, South Asia Programme, Gurgaon 122 016, IN
5 Orissa University of Agriculture and Technology, Bhubaneswar 751 003, IN

Abstract

Soils vary widely in their capacities to supply phosphorus (P) to crops because only a small fraction of the total P in soil is available to crops. Thus, the crop growth and yield are likely to suffer adversely unless soil is endowed with adequate native supply of plantavailable P, or else the soil receives readily available (inorganic) P fertilizers. In order to rationalize fertilizer P application to support sustained high productivity on one hand and address the environmental and economic concerns on the other, an in-depth understanding of native P supplies and P dynamics in soil is inevitable. In this context, the present article takes stock of the available information on the occurrence of P in soils, chemistry of P in soil, P quantity, intensity, and buffer capacity attributes of different soils vis-àvis the P uptake modelling, P dynamics in soil, P management in important cropping systems for enhancing its use efficiency, soil testing for plant-available P to prescribe fertilizer P application and losses of P through erosion and runoff to the water bodies leading to eutrophication.

Keywords

Cropping Sequences, Phosphorus Dynamics, Phosphorus in Soils.

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D. Adhikari ¹, Z. Reshi ², B. K. Datta ³, S. S. Samant ⁴, A. Chettri ⁵, K. Upadhaya ⁶, M. A. Shah ², P. P. Singh ¹, R. Tiwary ¹, K. Majumdar ³, A. Pradhan ⁵, M. L. Thakur ⁴, N. Salam ², Z. Zahoor ², S. H. Mir ², Z. A. Kaloo ², S. K. Barik ¹

Affiliations
1 Department of Botany, North-Eastern Hill University, Shillong 793 022, IN
2 Department of Botany, University of Kashmir, Srinagar 190 006, IN
3 Department of Botany, Tripura University, Suryamaninagar, Agartala 799 022, IN
4 G.B. Pant National Institute of Himalayan Environment and Sustainable Development, Himachal Unit, Mohal-Kullu 175 101, IN
5 Department of Botany, Sikkim University, Gangtok 737 102, IN
6 Department of Basic Science and Social Science, School of Technology, North-Eastern Hill University, Shillong 793 022, IN

Abstract

Categorization of species under different threat classes is a pre-requisite for planning, management and monitoring of any species conservation programme. However, data availability, particularly at the population level, has been a major bottleneck in the correct categorization of threatened species. Till date, threat assessments have been mostly based on expert opinion and/or herbarium records. The availability of primary data on distribution of species and their p opulation attributes is limited in India because of inadequate field survey, which has been ascribed to resource constraints and inaccessibility. In this study, we demonstrate that ecological niche modelling (ENM) can be an economical and effective tool to guide surveys overcoming the above two constraints leading to the discovery of new populations of threatened species. Such data lead to improved threat assessment and more accurate categorization. We selected 14 threatened plants comprising 5 trees (Acer hookeri Miq., Bhesa robusta (Roxb.) Ding Hou, Gynocardia odorata Roxb., Ilex venulosa Hook. f. and Lagerstroemia minuticarpa Debb. ex P.C. Kanjilal), 8 herbs (Angelica glauca Edgew., Aquilegia nivalis Falc. ex Jackson, Artemisia amygdalina DC., Begonia satrapis C.B. Clarke, Corydalis cashmeriana Royle, Dactylorhiza hatagirea (D. Don) Soo, Podophyllum hexandrum Royle, and Rheum australe D. Don), and 1 pteridophyte (Angiopteris evecta (Forst.) Hoffm.) having distribution range in North East India, Eastern and Western Himalaya, and Jammu and Kashmir. The study was carried out between 2012 and 2016. ENM-based survey led to the discovery and characterization of 348 new populations. The data so obtained helped in assigning conservation status to 10 species, which earlier were never classified due to data deficiency. Using the new population and distribution data of the remaining four species, only one was confirmed regarding its existing status and two species were classified as ‘Critically endangered’ instead of the present classification as ‘Endangered’. The fourth species was classified as ‘Critically endangered’ against the earlier category of ‘Least concerned’.

Keywords

Niche Modelling, Population Characterization, Threatened Plants, Threat Assessment.

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