Abstract:

【Objective】 The aims of this study were to build the biomass-based main geometric parameter dynamic models of rice root system according to the relationships between the total root length, the total root volume, the total root surface area per plant and the dry weight per plant of different rice cultivars under different fertilizer levels. 【Method】 Three rice cultivars, ‘Liangyou108’ (Hybrid long-shaped rice, V1), ‘86you8’ (Hybrid round-shaped rice, V2), and ‘Nanjing43’ (Round-shaped rice,V3), were planted in pots with two fertilizer levels: fertilizer (N:3.6 g/pot, P2O5:0.8 g/pot, K2O:3.6 g/pot) , and no fertilizer (with loamy soil) to obtain the root system morphological characteristics, the dry weight, etc., which were processed by SPSS v13.0 and Excel 2007. The models developed in this paper were verified using RMSE.【Result】The biomass-based dynamic models of the total root length were set up through analyzing relationships between the total root length and the biomass per plant from the experimental data in 2008, and then, the biomass-based dynamic models of the total root volume and the total root surface area per plant also were developed according to the principles of solid geometry, which were tested by using the experiment data in 2009. The results showed that the RMSE between the simulated values and the observed values of the total root length, the total root volume, and the total root surface area per plant were 490.660 cm/plant, 131.859 cm2/plant, and 2. 532 cm3/plant, respectively. 【Conclusion】 The models developed in this paper were reliable with mechanics, general adaptability, and interpretative characteristics in a certain extent, which would lay a basis for developing Functional-Structure Rice Models.

Key words: rice root system, biomass, geometric parameter model