Coconut-growing soils of Kerala: 2. Assessment of fertility and soil related constraints to coconut production

Growth, productivity and health of coconut plantations in humid tropics are influenced by soil qualities. Fertility of coconut-growing soils of Kerala was assessed by analysing samples drawn from the distinct agro-ecological regions of the state: Central and Eastern Palakkad, Northern Kerala, Central Kerala and Southern Kerala, Onattukara sandy plain and coastal sandy plain. The strongly acid soils of Northern and Central Kerala and Onattukara sandy plain are unfavorable for plant nutrient availability and microbial processes. Surface and sub-soils of Central Kerala and sandy plains have low levels of organic carbon. Available phosphorus was high in soils of Southern Kerala and Onattukara sandy plain. Plant available potassium was not adequate in these coconut-growing soils. The nutrient levels in soils of Central Kerala and sandy plain were extremely low. The same pattern was true for secondary nutrients calcium and magnesium. Soils of all regions have adequate levels of available sulphur, iron and manganese. Copper and zinc deficiency was recorded for laterite soils of central region and sandy soils of Onattukara and coastal plain. Plant available boron was deficient in all regions except for the soils of Southern Kerala. Molybdenum levels were marginal in coconut growing soils, except for the soils of Palakkad. Overhead climate and soil moisture availability does not constrain the palm in the state except for Eastern Palakkad where irrigation during dry period is an absolute necessity. The extensive areas of midland laterites and Onattukara sandy plain with strong acid reaction and aluminium in soil solution severely constrain coconut. The acid soils also suffer from deficiencies of potassium, calcium, magnesium, copper, zinc and boron. These soil related constraints affect coconut production significantly and alleviation of the same through liming and adequate application of deficient nutrients can ensure satisfactory yields from the palm

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Not AvailableThe sustenance of food and nutritional security are the major challenges of the 21st century. The domestic food production needs to increase per annum at the rate of 2% for cereals and 0.6% for oilseeds and pulses to meet the demand by 2030. The Indo-Gangetic Plains (IGP) and the black soil regions (BSR) are the two major food production zones of the country. Since irrigation potential is limited and expansion of irrigated area is tardy, rainfed agriculture holds promise to satisfy future food needs. Frontline demonstrations of these two regions have shown that there is a large gap at the farmers’ and achievable levels of yields. This gap can be filled by adopting scientific approach of managing the natural resources. There is tremendous pressure of biotic and abiotic stresses hindering the crop production and that warrants for a systematic appraisal of natural resources. The National Bureau of Soil Survey and Land Use Planning (NBSS&LUP) under the Indian Council of Agricultural Research (ICAR) divided the country into 60 agro-ecological sub-regions (AESRs) in 1994 by superimposing maps on natural resources like soils, climate and length of growing period (LGP) for crops and other associated parameters. With the passage of nearly two decades and the advent of modern facilities of database management and improved knowledge base on natural resources, a need was felt to revise the existing AESR map to reach near the ground reality of crop performance. The new database stored in soil and terrain digital database (SOTER) has helped in modifying the AESR delineations of the BSR (76.4 m ha) and the IGP (52.01 m ha). The estimated available water content, saturated hydraulic conductivity and use of pedo-transfer functions in assessing the drainage conditions and soil quality have helped in computing with improved precision the LGP, and revise the earlier AESRs in BSR and IGP areas. This innovative exercise will be useful for the future AESR-based agricultural land use planning.Not Availabl

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Not AvailableLand evaluation is carried out to assess the suitability of land for a specific use. Land evaluation procedures focus increasingly on the use of quantitative procedures to enhance the qualitative interpretation of land resource surveys. Conventional Boolean retrieval of soil survey data and logical models for assessing land suitability, treat both spatial units and attribute value ranges as exactly specifiable quantities. They ignore the continuous nature of soil and landscape variation and uncertainties in measurement, which may result in the failure to correctly classify sites that just fail to match strictly defined requirements. The objective of this article is to apply fuzzy model to land suitability evaluation for major crops in the 15 benchmark sites of the Indo- Gangetic Plains (IGP) and 17 benchmark sites of the black soil regions (BSR). Minimum datasets of land characteristics considered relevant to rice and wheat in the IGP and cotton and soybean in the BSR were identified to enhance pragmatic value of land evaluation. The use of fuzzy model is intuitive, robust and helpful for land suitability evaluation and classification, especially in applications in which subtle differences in land characteristics are of a major interest, such as development of threshold values of land characteristics.Not Availabl

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Not AvailableCurrent status of land/soil resources of the Indo- Gangetic Plains (IGP) is analysed to highlight the issues that need to be tackled in near future for sustained agricultural productivity. There are intraregional variations in soil properties, cropping systems; status of land usage, groundwater utilization and irrigation development which vary across the subregions besides demographies. Framework for land use policy is suggested that includes acquisition of farm-level data, detailing capability of each unit to support a chosen land use, assess infrastructural support required to meet the projected challenges and finally develop skilled manpower to effectively monitor the dynamics of land use changes.Not Availabl

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Not AvailableUnderstanding the physical quality of soil that influences its hydraulic behaviour helps in formulating appropriate water management strategies for sustainable crop production. Saturated hydraulic conductivity (Ks) is a key factor governing the hydraulic properties of soils. Ks can be estimated through various techniques. In the present article we have developed and validated the regression models to predict Ks of the soils of the Indo- Gangetic Plains (IGP) and the black soil regions (BSR) under different bioclimatic systems. While particle size distribution was found to be a key factor to predict Ks of the BSR soils, organic carbon was found useful for the IGP soils. Moreover, the models for Ks of both soils were strengthened by putting in CaCO3 and exchangeable sodium percentage content. It seems there is ample scope to study the interaction process for revising Ks to desired levels through management practices in these two important food-growing zones. An index of soil physical quality, derived from the inflection points of the soil moisture characteristic curves could well explain the impact of management practices on soil physical quality.Not Availabl