乌兰布和沙区紫花苜蓿根系吸水模型

在实测获得根重密度和土壤含水量的基础上,运用土壤水分运动方程及Penman-Monteith公式,计算得到干旱沙区不同水分处理下紫花苜蓿(MedicagosativaL.)根系吸水速率和蒸腾强度.结果表明紫花苜蓿根系吸水速率与土壤剖面含水量和根重密度密切相关.苜蓿地水分消耗规律在分枝期以棵间蒸发为主,在开花期和结实期以植株蒸腾为主.建立了干旱沙区紫花苜蓿根系吸水模型,经回归分析得到模型中的各个参数,通过对回归结果的方差分析表明,模型的相关性较好(R2=0.890,p<0.05);另外从模型验证的结果看,土壤剖面含水量模拟值与实测值基本吻合,说明本文提出的根系吸水模型其可靠性较好.

A SIMULATION MODEL FOR WATER UPTAKE BY ALFALFA ROOTS IN THE WULANBUHE SANDY DESERT

Transpiration intensity and water uptake rate were studied in roots of alfalfa (Medicago sativa L.) grown under different water conditions in an arid sandy region.This was achieved using soil moisture content and root weight density data with water movement equations and the Penman Monteith formulation.The results of this analysis showed a significant correlation of water uptake rate with soil profile water content and root weight density.During the bifurcation stage evaporation accounted for the largest loss of water from the system, but this was replaced by transpiration in the flowering and productive phases. A model was developed to simulate water uptake by alfalfa roots, the parameters of which were obtained using regression analysis.Variance analysis showed that the model effectively simulated water uptake by roots( R 2 =0.890, p <0 05).