Inter-tillage technique for semi-dry rice

Rice cultivation associated with rain fed and an irrigated environment is known as semi-dry rice cultivation.

It is being practised in areas where the water availability through rainfall or any irrigation source is not sufficient to raise a transplanted crop on time.

In Tamil Nadu it is widely adopted in tank fed areas of many coastal districts.

While comparing transplanted or directed seeded puddled rice, owing to lack of wet tillage such as puddling, the present semi dry rice system provides more leaching losses of applied nutrients along with percolation losses of irrigation water.

This results in poor nutrient uptake, that reflects on poor grain yield, even by advocating improved technologies

Semi dry rice is usually grown with initial dry tillage and seeds are drilled in lines with a seed drill.

The drilled crop provides sufficient row space that facilitates wet inter tillage with suitable implements especially at the time of conversion of dry to wet system, usually 6 to 7 weeks after dry sowing. The adoption of wet inter tillage is able to alter the soil physical environments and thereby minimize percolation losses of irrigation and leaching losses of applied nutrients during wet environment.

To find out the possibility of increasing the sustainable productivity of semi-dry rice, field experiments were conducted at the College of Agricultural Engineering, Kumalur.

The experiments indicated that inter puddling in row space once with bullock drawn inter tillage hoe followed by stirring the open and wet soil in rows twice at three days interval with rotary weeder, could considerably reduce the percolation losses of irrigation water by 26 per cent.

This in turn minimizes the leaching loss of applied nitrogen and potassium by 53 per cent and 26 per cent respectively recorded 32 per cent more grain yield .

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