Study on the Mechanisms of Yield-raising and Quality-improving for Paddy Rice Under Water-saving Irrigation

PENG Shi-zhang; HAO Shu-rong; LIU Qing; LIU Yong; XU Ning-hong

doi:10.3969/j.issn.1672-3317.2000.03.003

Abstract：Some ecological indexes, as roots, stems, leaves and tillers in different growing stages,some soil physical and chemical properties, as soil fertility and soil moisture, and yield formation fac-tors, grain quality, resistance to diseases and lodging in paddy rice were surveyed and analyzed sys-tematically in Yellow River Irrigation Area in Ninxia Autonomous region. Experiment data indicatethat benefits in water saving and yield raising in paddy rice are significant under control irrigation sys-tem. The yield on fields with control irrigation reaches 10398 kg/hm2, an increase of 5.3000, comparedto those with conventional irrigation system. 7057.5 m3/hm2 of irrigation water is saved at average forper hectare of land, a reduction of 38. 8%, compared with the conventional irrigation method. Also,the production quality is improved correspondingly under control irrigation, as content of coarse pro-tein increases by 0.21%, and percentage of integral fine rice rises by 1.59%. At the same time, thedisease and lodging resistance of plants under control irrigation are improved obviously. The percent-age of disease plants decreased by 19.8%, the percentage of infected leaves reduces by 15.4%, andthe lodging rate reduces by 18.300. The Experimental results reveal that through reasonable adjust-ment of water layer and soil moisture in paddy rice fields, the soil properties in crop root zone can beimproved significantly, and a good grow condition for roots, stems, tillers, leaves, ears and grainscan be established, and thus a relative reasonable canopy and forage structures can be formed. On theother hand, relative strong stalks is useful to prevent plants from lodging. Under control irrigation,tillers usually form relatively early and grow quickly, percentage of effective tillers and leaf area indexincrease rationally, ears are larger, number of stuffy grain per ear greater, weight per one thousand ofgrains higher and production quality better.