Raised bed sowing – A climate change adaptive maize cultivation practice for coastal saline region

Abstract

The coastal areas are mostly mono-cropped with poor/low yielding kharif rice. During rabi season salinity is the main problem restricting the choice of crops to be grown. The cropping intensity is low and most of the land remains fallow during the rabi season. The main obstacle to intensification of crop production in the coastal areas is seasonally high content of salts in the root zone of the soil. The salts enter inland through rivers and channels, especially during the latter part of the dry season, when the downstream flow of fresh water becomes very low. The salts enter the soil by flooding with saline river water or by seepage from the rivers, and the salts become concentrated in the surface layers through evaporation. This phenomenon has been increasing in recent year due to the effect of climate change. Therefore, for successful cultivation of rabi crops, salinity from the root zone should be reduced, soil moisture should be conserved and less water requiring crops and adaptation strategies are to be selected. To manage the issue of high root zone salinity, effective establishment methods are essential. In the present study, rabi crops like maize and rapeseed were sown under three tillage practices viz. direct/dibble sowing of seeds immediately after harvest of kharif rice by making a hole at the point of seeding and covering the seeds by dry farm yard manure (FYM); second tillage practice was conventional/ normal tillage after the drying of the residual soil moisture from the fields and then ploughing by a tractor followed by secondary tillage operations by power tiller and third tillage practice was making raised beds (RBS). Dibbling was done immediately after harvest of kharif rice to use the residual soil moisture, whereas normal sowing and RBS was done when soil moisture attained tillable condition. The direct sowing helped in the early establishment of rapeseed which resulted in its maturity under favorable temperature/winter conditions. With delay in its sowing the temperature increased and resulted in severe incidence of aphid attack and produced lowest yield. Maize crop however responded differentially to the establishment method and it produced highest yield and net return with raised bed sowing. This system reduced the irrigation water requirement by 10-18%, increased irrigation water productivity by 50-80% and the soil salinity in the month of April was reduced by 37% in comparison to other methods of establishments. RBS method helped maize crop to withstand the occasional waterlogging caused by torrential rain during dry season. This study revealed that cultivation of hybrid maize by RBS is highly profitable and climate resilient management practice for salt affected coastal region of India.