文献类型： 外文期刊

作者： Zhao, Zhigan ¹ ; Wang, Enli ² ; Xue, Lihua ¹ ; Wu, Yongcheng ¹ ; Zhang, Jingting ¹ ; Wang, Zhimin ¹ ;

作者机构： 1.China Agr Univ, Beijing 100193, Peoples R China

2.CSIRO Land & Water, Canberra, ACT 2601, Australia

3.Xinjiang Acad Agr Sci, Grain Crops Res Inst, Urumqi 830091, Peoples R China

4.Hebei Acad Agr & Forestry Sci, Shijiazhuang 050031, Peoples R China

关键词： root biomass;rooting depth;winter wheat;North China Plain;APSIM

期刊名称：20TH INTERNATIONAL CONGRESS ON MODELLING AND SIMULATION (MODSIM2013)

ISSN：

年卷期： 2013 年

页码：

收录情况： SCI

摘要： Accurate modeling of root biomass and root distribution of crop plants has become increasingly important to address issues related to carbon sequestration in soil and resource use efficiency of crops under different environmental and management conditions. However, the performance of crop models for simulating crop root system has been rarely tested in many environments due to lack of detailed data caused by the difficulty to measure roots. In this paper, we present detailed measurement data on root biomass and distribution in 0-200cm deep soil profile at key developmental stages of wheat crop at Wuqiao in the North China Plain, and compare them with the root dynamics simulated by the agricultural systems model APSIM. The objectives are to test the model performance for modeling root biomass and distribution, and to investigate the potential impact of errors in root modeling on simulated yield responses under different levels of water and nitrogen supplies through changes in irrigation and nitrogen applications. The data were collected in two field experiments carried out in the 2003-04 (Exp 1) and 2008-09 (Exp 2) winter wheat growing seasons, each with three irrigation treatments and one fertilizer-N application rate of 158 kg/ha (urea N). Irrigation scheduling included: no irrigation (W0), one time of irrigation (750m(3)ha(-1) = 75 mm each time) at jointing stage (W1), two times of irrigation at jointing and flowering stages (W2), three times of irrigation at upstanding (double ridges), booting and start of grain filling stages (W3) and four times of irrigation at upstanding (double ridges), jointing, flowering and start of grain filling stages (W4), all as flood irrigation. Irrigation treatments for Exp 1 were W0, W2 and W4, and for Exp 2 were W0, W1 and W3. All the experiments received 75 mm irrigation applied 5 days before sowing to ensure good emergence. In Exp 1 (2003-04), wheat root samples were collected using a drill (8cm in diameter) down to 200cm depth with a 20 cm interval before winter and at flowering and maturity time. In Exp 2 (2008-09), soil monoliths from a 20 cm (length) x 15 cm (width) area down to 200 cm were extracted, with 20 cm interval for the top two samples, and 40 cm interval for the samples at deeper depth. This was done five times: before winter, and at stages of upstanding, jointing, flowering and maturity. Roots were separated using double-layered sieves (1mm diameter) by washing out the soil with water. In addition, shoot biomass was also measured in each experiment. All plant samples were oven dried at 70 degrees C to constant weight to measure biomass. APSIM version 7.5 was used to simulate the root and shoot growth of the winter wheat crop against the experimental data. Compared to the measurements from field experiments, APSIM version 7.5 underestimated the rooting front advance and final rooting depth of winter wheat, but overestimated the root biomass and root shoot ratio at maturity by 100-200%. The model also simulated simultaneous increase in both shoot and root biomass with increased irrigation supply, but measurements showed increase only in shoot biomass, not in root biomass. Correction to the simulations of rooting depth and root biomass based on the data led to little impact on simulated shoot biomass and grain yield under conditions of sufficient nitrogen supply, but higher simulated grain yield when nitrogen was deficient. Studies are needed to further investigate APSIM's ability to simulate root growth and its impact on biomass growth and carbon cycling in farming systems across different environments.