Last Updated:23rd June,2022  

Natural Resource Management

Significant Achievements
Site specific farming systems
Integrated Farming Systems is a sound strategy for harmonizing judicious use of land, water, vegetation, livestock and human resources to meet multiple demands and increase farm income under island conditions. Two site specific climate smart farming system models were evaluated for increasing farm production and doubling the farm income. Crop + dairy mixed farming system recorded significant increase in farm production from 2.8 t ha-1 to 36.9 t ha-1 REY with net income of Rs. 2,14,000/- and employment generation of 365 man days year-1 . Coconut + piggery based system with coconut multi-tier cropping, fish cum poultry and livestock recorded net income of Rs. 223000/- with production of 36 t ha-1 and employment generation of 198 man days year-1 under integrated farming system (IFS).
Land degradation management
In the coastal and humid tropical island regions waterlogging and soil salinity are serious threat to the sustainability of rainfed agriculture due to sea water inundation and intensive monsoonal rainfall. Under such situation the raised bed system reduced the overall salinity by 85%, improved the drainage of the raised beds, harvested rain water, and prevented entry of tidal and runoff water into the furrow. Based on the rate of reduction in salinity lag phase, leaching phase and equilibrium phase were recognised during the leaching of salts from the raised beds. Waterlogging and salinity peaks at different seasons requiring different management strategies but, raised bed and furrow system are effective in addressing this challenge together.
The changes in land degradation and the effect of conservation measures for pre- (2000) and post-2004 tsunami periods (2006, 2019) were recorded using temporal remote sensing data, field observations and a GIS-based revised universal soil loss equation. The results showed that erosion, leaching, acidification, salinization, and drainage congestion were the major land degradation processes that could be traced to post-tsunami human activities (R2 = 0.634). The annual crop area exhibited a 0.42% loss, whereas the plantation crop area increased by 0.46%, indicating the abandonment of annual crops that resulted in an increased fallow area (21 km2) during the post-tsunami period. As a consequence, degraded land increased by 2.5% of the total geographical area which was affected by water erosion (2.3%) and chemical degradation (0.25%).
Water management
Harvesting of water through dug out or plastic lined ponds could be a boon for not only increasing cropping intensity but also for alleviating moisture stress to crops by supplemental irrigation. Therefore, pond lining with different materials was developed / refined and popularised for effective control of seepage losses. The shelf life of lining material can be increased by lining the tank with plastic film and reinforced plaster (1:6) on sides and 15 cm thick soil layer at bottom for higher life period.
• Study of water stress management showed that plastic mulching recorded maximum plant height and attained early flowering with maximum fruit length (15 cm), no. of fruits (15.5), fruit weight (20 g) which resulted in higher yield (311 g/plant equivalent of 9.95 t/ha) in okra. Similarly application of hydrogel + K & Ca foliar spray recorded maximum fruit length (15.7 cm), no. of fruits (14.8), fruit weight (20.1 g), which resulted in higher fruit yield (298 g/plant equivalent of 9.56 t/ha).
Production Technology
Seaweeds contain comparable quantity of macro nutrients especially N and K, higher amounts of Ca, Mg and trace elements like Fe than common green manure crops. Application of 25% aqueous extract of seaweed (Sargassum wightii) recorded significant increase in grain yield (21.3 g plant-1) when compared to control (15.4 g plant-1) in cowpea.
Application of Nano Urea (Liquid) as foliar spray to rice recorded 14.4- 16.7 % increase in rice grain yield and saving of 34-49% fertilizer nitrogen over 100% RDF application.
Promotion of organic farming in high value crops was carried out; preparation and application of organic inputs such as panchagavya, enriched compost, pest repellent, bioconsortia for growth promotion and P and Zn solubilizers were standardized and demonstrated at 10 farmers' fields.
Standardized soilless growing media (cocopeat + saw dust (1:1 v/v) and cocopeat + vermiculite + saw dust (1:1:2)) and fertigation requirements for high value vegetables for island ecosystem. Vertical farming system in terms of light, growing media, fertigation and plant protection was evaluated for growing round the year high value leafy vegetables were tried.
The soils under plantation areas are predominantly acidic to varying degree due to leaching of soluble salts. Application of lime is a costly proposition hence locally available organics like coconut husk, vermicompost, poultry manure, and glyricidia alone or in combinations as amendment was evaluated. Application of different organic amendments @20 t ha-1 increased the soil pH relative to control. The relative liming efficiency was highest for poultry manure and least for coconut husk compost used alone. Organic amendments also found to significantly increase the yield of maize as compared to control and lime.
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