Study On Water And Fertilizer Utilization Of Upland Rice Under Water Saving Irrigation And Application Of ORYZA2000 Model

The subject is based on the water-saving irrigation for rice and had made a study on the effect of density and N-fertilizer and different water-saving methods on upland rice with a split-plot experiments. The experiments were performed in Huibei water resources science experimental station in Kaifeng, Henan province in 2004. The main treatment was irrigation regimes (W1: water-saving irrigation (Flushing irrigation at -30 kPa), W2: Rainfed with survival irrigation). The sub-treatment is N-fertilizer application rate (N1: 225 kgN/hm2; N2: 300 kgN/hm2). The sub-subtreatment was density (D1: spacing between rows was 30 cm; D2: spacing between rows was 24 cm). The varieties of fertilizers are N-urea, P-Ca (H2PO4)2, K-KC1, Zn-ZnSO4, Fe-FeSO4. The main results were below:1. In this study, leaf area index, panicles/m2, biomass of leaves and stems were higer in high density than in low density. However, the root length, biomass of root and ratio of root to shoot were higher under the W2 treatment with relative less water than those under the Wl treatment with relative more water. There are no differences for plant height among the all treatments.2. There was a trend that nitrogen content of root, stem and leaf in the W2 treatment with relative less water were higher than those in the Wl treatment with relative more water respectly, especially in the vegetative growth stage. However, the respective N-cumulant in root, stem and leaf were higer in the high density than in the low density treatment. Among the N-fertilizer treatments, nitrogen content and N-cumulant were higher in high N-fertilizer treatment than in low N-fertilizer treatment, during the early growth seasons but no differences during the late growth seasons. The percentage of N in grain was higer in low N-fertilizer treatment than in high N-fertilizer treatment.3. Comparing the yield components, the panicles No./m2 was higher in high density treatments than in low density treatments; and higher in low N-fertilizer treatment than in high N-fertilizer treatment. However the filled grains numbers per panicle was just contrary. The grain yield had a similar regulation to that of panicle numbers/m2, but the thousand grain weight and the filled grain rate had no differences between different treatments. In this study, the optimum N-application rate was 225 kgN/hm2 and direct-seeding density was 24 cm between the rows with seed rate 187.5 kg/hm2.4. Water productivitywas higher in low N-fertilizer than in high N-fertilizer. While in two water treatments, water productivity of W1 treatment with relative more water was lower than that of W2 treatment with relative less water.5. ORYZA2000 plant growth model could be used for simulating the biomass, grain yield, LAI and other items of upland rice. The results predicted by ORYZA2000 indicated that yields have no significant differences between the different water-saving irrigation methods, but water productivity of F10 (irrigation when the ground water less than -10 KPa) and F15 (irrigation when the ground water less than -15 kPa) were lower than that of the other treatments; among the different groundwater depth treatments, yields and water productivity of the other groundwater depth treatments have no differences except that yields and water productivity of 1000 cm depth treatment was obviously low.