水稻根长增长和养分吸收动态及其模拟模型

Dynamics of rice root length and nutrient uptake and their simulation models

采用溶液培养和田间试验,研究水稻根长增长和氮、磷、钾吸收动态。在改进蔬菜根长和养分吸收动态模型基础上,建立了适用于一个生长周期的水稻根长增长模型、单位根表面积氮、磷、钾吸收速率模型及其累积吸收动态模型。6个根长增长模型和18个根表氮、磷、钾吸收速率模型以及36个氮、磷、钾吸收动态模型的模拟效果达显著水平。结果表明,随着种植时间的推移,水稻根长增长和氮、磷、钾累积吸收量在整个生育期呈现"S"型特征;根表养分吸收速率在生长前期随种植时间迅速提高并达到最大值,过后则按指数规律下降。溶液培养试验看出,生育期120 d水稻最大根长增长速率和最大根长分别为播种后68.8±5.4 d和108.4±3.9 d,品种间差异很小;最大根长增长速率和根长则为4531.5±1529.4 cm/(pot.d)和(2.8931±0.6237)×105cm/pot,品种间差异较大。田间试验看出,不同施肥处理的氮、磷、钾吸收速率基本同步,早晚稻插秧后约50～60 d根系养分吸收能力达到峰值,临近成熟时养分吸收量达到高峰。研究结果为水稻中后期养分管理提供了科学依据。

Water culture and field experiments were conducted to study the dynamoics of rice root growth and nutrient uptake.Root growth model,NPK in unit root surface area uptake velocity model and NPK cumulative uptake model were set up for rice in fitting its one growth period based on the improved relative modes for vegetable.In general,six root length growth models and eighteen NPK uptake velocity models and thirty-six NPK uptake dynamic models are all at the statistic significance levels.The results show that the dynamic characteristics of rice root length and NPK uptake present ＂S＂ type in one growth period,while NPK uptakes velocity on root surface increase rapidly in growth prophase and reach thier maximum values,and then have exponential decreases afterwards.The results of the water culture erperiment show that the times of maximum root length increased velocity and maximum root length are 68.8±5.4 days and 108.4±3.9 days respectively in 120 days growth period,and their differences are little among rice cultivars.The maximum root length increased velocity and maximum root length are 4531.5±1529.4 cm/（pot·d） and（2.8931±0.6237）×105cm/pot respectively,and their differences are obvious among the cultivars.Field experiments show that NPK uptake velocities in rice almost are in a similar trend under different fertilization treatments.NPK uptake velocities in rice reach their marximum values at 50 th-60 th day after the transplanting.But the marximum uptake capacities for NPK present near maturity.These results provide a scientical base for nutrient management at the middle and late stages of rice growth.