Effect Of Different Cultivation Patterns On Grain Yield And Nutrient Use Efficiency Of Rice Cultivar Lianjing 7

This study investigated if improved crop management could increase both grain yield and nutrient use efficiency in rice. A super rice cultivar Lianjing 7(japonica inbred) was grown in the field with six cultivation patterns including no nitrogen application (ON), local farmer’s practice (LFP, control), improved crop management (ICM), high yielding and high efficiency (HYE) management, super high yielding and high efficiency (SHYE) management and deep-plowing high yielding and high efficiency (DHYE) management. In each high yielding and high efficiency management pattern, crop management practices were improved, such as increasing planting density, decreasing nitrogen (N) application rate, applying more N at late growth stages, precise irrigation, applying organic fertilizer and deep-plowing. The yield formation, population growth characteristics, root senescence, and nutrient absorption, allocation and utilization were studied. The main results were as follows:1. The grain yield was 8.62 t hm-2 under the LHY. The ICM, HYE, SHYE and DHYE increased the yield by 12.88%,18.21%,29.23% and 28.19%, respectively, over the LHY. Increase in grain yield was mainly attributed to the increase in number of spikelets per unit area (increased by 15.47% to 27.86%) under the high-yielding and high efficiency cultivation patterns. There was no significant difference in the seed-setting rate and 1000-grain-weight among the cultivation patterns.2. Compared with the LFP, the ICM, HYE, SHYE and DHYE increased the percentage of productive tillers, improved leaf composition significantly, enhanced photosynthetic potential, population growth rate and net assimilation rate, increased matter accumulation from heading to maturity and grain-leaf ratio, and improved the morphology and physiology of roots (root dry weight, ratio of root to shoot and root oxidation ability), slowed the senescence of a root system.3. The partial factor productivity, agronomic efficiency, recovery efficiency and the physiological efficiency of N fertilizer under the ICM and HYE were significantly higher than those under the LHY. Both SHYE and DHYE significantly increased the agronomic efficiency, recovery efficiency and the physiological efficiency, but showed no significant difference in the partial factor productivity when compared with LHY.4. The absorption peak of N, phosphorus (P) and potassium (K) occurred from the jointing stage to the heading stage, accounting for 36.30% to 41.42%,36.34% to 42.56% and 48.86% to 55.98%, respectively, of the total accumulation of the nutrients. The uptake amount of the N, P, and K under the HYE, SHYE and DHYE were significantly higher than those of the LFP from jointing to heading, heading to waxy ripe, and from waxy ripe to maturation, The total absorption of N, P, K under the ICM, HYE, SHYE and DHYE were increased by 14.25% to 40.94%,17.15%to 45.06%,16.86% to 38.34%, respectively, over those under the LHY. their nutrient transport capacity, translocation efficiency and harvest index were also significantly increased. Compared with those under the LHY, the absorption amount for grain production of N, P, K under SHYE were significantly increased, phosphorus absorption amount for grain production of DHYE was also increased.The results indicate that the high yield and high efficiency cultivation patterns could increase both the rice yield and the nutrient use efficiency, and improve the population quality of rice. Increasing planting density, decreasing N application rate, applying more N at late growth stages, precise irrigation, applying organic fertilizer and deep-plowing could be taken as key cultivation techniques for a high yield and high efficiency cultivation pattern.