Title : Tolerance of rice plants at variably reclaimed saline soils: Effectiveness of organic manure
Soil salinization is a major problem for growing population as it limits the productivity of land and thus affects the livelihood. Increasing salinization is the result of altered weather conditions due to global warming and various anthropogenic activities. To fulfil the demand of increasing population, reclamation of degraded land is practised by local farmers for agricultural purposes. The present study was conducted with rice (Oryza sativa L.) plants growing on reclaimed saline areas of Varanasi, Chandauli and Mirzapur districts in Uttar Pradesh, India, which were earlier highly saline to various extents. Six reclaimed sites were chosen on a salinity gradient and were categorized as least saline (Rajatalab (RJT) and Beerbhanpur (BBN)), moderate (Mirzamurad (MZM) and Baraipur (BRP)) and highly saline (Dharahara (DHR) and Salempur (SLM)) sites. In two of the sites of each categories, one was receiving organic fertilizer along with chemical fertilizers and the other one only received chemical fertilizers. Soil quality parameters such as total organic carbon, humic acid, total nitrogen and available phosphate were low at sites with high soil salinity. Soil salinity and organic manure amendment differentially affected rice test weight. Damage due to high salinity was highest at sites with maximum salinity (SLM), where the plant failed to reach reproductive maturity. However, the other high saline site DHR maintained its yield due to organic manure amendment. Similarly, at low saline site (BBN), the plants showed reduced productivity in absence of organic manure application. Productivity of rice crop depends on nutrient condition of soil which was directly affected by soil salinity and agronomic practices. Nutrient management practices attempted by the farmers were found responsible for productivity of rice and also in reclamation process. Organic manure amendment helped the soil to reclaim better than the sole use of chemical fertilizers.