RICE IN SRI LANKA-Water Management
- Reduction of time taken for land preparation using total killing herbicides (e.g. Paraquat). This also reduces one tillage operation and conserve irrigation water.
- Dry sowing in well drain or sandy soils where water use is very high.
- Mulching straw after seeding to conserve moisture which also facilitates early and uniform seed germination and weed suppression.
- Careful plastering of bunds and “puddling” the field well to avoid rapid percolation and lateral seepage. This will also assure maintaining of standing water, without a requirement of frequent flooding.
- Utilizing the potential of existing rainfall for growing rice through timely cultivation It will also maximize irrigation water use efficiency.
- Initial land preparation with the onset of rains will conserve irrigation water and assist ploughing deep which facilitate escaping terminal drought in longer duration varieties.
- Selection of a crop age class to suit the available water
- Short aged varieties need low water requirement but at the expense of yield
- The cost of land preparation and other agronomic practices would be the same or higher for short age varieties except a small decrease in use of fertilizers and pesticides
- Short growing seasons demand better weed control and optimum timing which could increase cost of production
- Very short duration (75 days) varieties (Bg 750) could be used in drought prone areas to avoid terminal drought but potential yield is rather low (70 bu/ac)
- Kakulan type varieties with good weed competitive ability (e.g. 62-355) could be used in areas with short growing seasons.
- Rice does not require standing water to maximize yields. Maintaining saturated condition could save up to 40% of water in clay loam soils (IRRI, 1995) without yield reduction (weed control should be done separately)