Dynamic Simulation Of Maize Biomass Based On Photosynthate Allocation

Maize is an important food and economic crops that plays a decisive role in the aspect ofensuring food security and meeting the market demand. This study constructed a phase-basedmaize photosynthate allocation model in terms of the characteristics of maize photosynthateallocation during its growing period, together with the Friendlingsten model based onfunctional equilibrium hypothesis, the priority allocation principle of the metabolic pool aswell as the predator form of the Lotka-Volterra model，with which dynamic simulation ofmaize organs’ biomass was realized. The model is validated in terms of the field experimentdata of spring maize from Jinzhou Agricultural Ecosystem Research Station during2005-2011.The main results are listed as follows:（1） The maximum leaf area index (LAI_max) could be taken as an indicator of maizeentering the reproductive stage.≥10℃effective accumulated temperature of maize fromseeding and emergence to the maximum leaf area index is approximately invariable around1085.3℃d and1010.4℃d, respectively. Thus, it could be an indicator determining themaximum leaf area index of the spring maize in Jinzhou.（2） A universal dynamic model of maize relative leaf area index was developed on thebasis of the modified Logistic equation and the≥10℃effective accumulated temperatureindicator of LAI_max. In order to obtain the accurate simulation of maize relative leaf area index,the field observation data should be no less than3years with at least4times observationduring the growing period each year. The proper four observation times during maize growingperiod were suggested as about20d after seeding emergence for the first observation, andmonthly thereafter for every observation. This model could give better simulations for the LAIdynamic of different seeding periods, varieties, and planting densities, and it provided areference for accurate simulation of leaf growth and the photosynthate allocation.（3）The maize growing period could be divided into3phases by the jointing stage andLAI_max: vegetative growth phase, vegetative and reproductive growth concurrency phase, andreproductive growth phase, and phase-based maize photosynthate models were established. The simulation of photosynthate allocation of the vegetative growth phase was based on theFriendlingsten model in terms of the functional balance hypothesis, which could illustrate theeffect of the variation of light, temperature, water and nutritious conditions on thephotosynthate allocation to the root and the stem, and consequently on the allocation to theleave. At the vegetative and reproductive growth concurrency phase, as few photosynthatewas allocated to the spike, so the photosynthate allocation model of the vegetative growthphase was exploited at this phase. At the reproductive growth phase, the allocation to thevegetative organs was not considered. Except for the consumption of respiration, the rest ofthe photosynthate was all distributed to the spike. This model took the re-allocation from thevegetative organs to the spike into consideration. The simulation of the re-allocation wasrealized by modifying the predator form of the Lotka-Volterra model. The re-allocation modelconsidered the requirement of the spike as well as the discrepancies in the re-allocationabilities of root, stem and leaf.（4） The established phase-based maize photosynthate models were validated based on thefield experiment data of spring maize from Jinzhou Agricultural Ecosystem Research Stationduring2005-2011. The results indicated that the models had quite good performance. Theexplanation rate （R2） was0.950for the simulated total dry weight and0.828for the simulatedvegetative organs. Among the various organs of spring maize, the explanation rate reached0.836for the simulated leaf and0.723for the simulated spike. The explanation rate for thesimulated root and stem were0.668and0.601, respectively. The relative error （RE） forsimulated leaf, stem and root were0.11,0.09and-0.06, respectively, and it was0.07for thevegetative organ. The simulation value was lower for the spike （RE=-0.17） and the total dryweight （RE=-0.01）.