Several foreign methods of dry rice cultivation can be used for reference.
Hole planting method for dry rice cultivation. This new method was invented by the Tice Farm in New Orleans, USA. Specific operation: on moist no-till land, use a small hole-punching seeder (machine) to punch a hole about 3cm in diameter and 13-15cm deep in the soil. While punching the hole, immediately sow 1-2 rice seeds, then cover the hole with soil and fertilizer, and fill the hole with water while keeping the soil around the hole only moist. Under normal circumstances, no water needs to be given within 40 days after sowing, so that the rice roots grow deep and have a strong root system, which can effectively absorb underground water. While the rice seedlings are growing, weeds can be removed once between the rows (loosening the soil 2-3cm deep), which both removes weeds and serves as intertillage. After 40 days, if there is no rain, another soaking irrigation can be given until maturity and harvest. This method requires only 15%-20% of the water consumption of rice, is convenient for mechanized operation, and is a new method of dry rice cultivation. If a water-retaining agent is covered over the holes, the water consumption can be further reduced to 8%-10%.
Paper mulch dry rice cultivation method: This was first adopted by the Niigata Farm in Japan. This method mainly uses old newspapers, waste paper or recycled paper mulch (which lowers the cost) as covering mulch. For rice cultivation, only one soaking irrigation is needed. The paper mulch is laid on the soil surface (after soaking in water, the paper mulch clings to the surface layer), so it will not be blown away by the wind, can block direct sunlight, prevent water evaporation, conserve water and preserve soil moisture, and reduce weed growth. After 2-3 months, the paper mulch gradually decomposes and integrates into the soil, leaving no harm. This method can reduce water consumption by 55%-70%. This method can also be used for water conservation in other dry crops.
High-yield semi-dry rice cultivation technology: The Japan Hara Masashi Rice Technology Research Institute has developed a new technology for high-yield semi-dry rice cultivation. This technology is very different from traditional rice cultivation and water use. The general requirement is: in the early stage, mainly expose the mud, use soaking irrigation, and aerate to promote rooting. This requires only about 30% of the conventional water consumption, and can also suppress pests and diseases and reduce rice production costs. Its technical points are:
1. When transplanting rice seedlings, the field should preferably be "exposing the mud." If the weather is clear after transplanting, soaking irrigation can be used, but flooding irrigation or broad irrigation must not be used; the water should just cover the mud. Check the field 15 days after transplanting. Step with your feet. Wherever bubbles emerge around the footprints, water must not be applied. After soaking for three days, check again. If bubbles still emerge, continue exposing the field. Always use this alternating combination of "soaking water - exposing the field" to promote the growth of the rice root system.
2. After young panicle formation, generally use intermittent irrigation to coordinate the relationship between the nutrients needed for the growth of the underground part (roots) and the aboveground part (stems and leaves), and promote steady growth of rice in the middle stage. Before applying sugar fertilizer, first dry the field until the soil moisture reaches an unsaturated state. After fertilizing, apply thin water until the soil water content is saturated, using water to carry fertilizer into the soil. Do not use flooding irrigation. Improve fertilizer use efficiency.
3. At heading, keep the field soil moisture in a saturated state. If high-temperature and dry weather occurs, appropriately irrigate to maintain a water layer 6 2cm deep. After full heading, maintain soil moisture in the early stage, and adopt moist irrigation in the later stage, using air to nourish roots, roots to protect leaves, and leaves to increase weight. More than ten days before harvest, the soil gradually changes from moist to dry, to prevent sudden dehydration or premature dehydration from causing serious impact.