Functional-structural modeling applied to Brazilian silvipastoral systems

Abstract

The growing population increase of the planet brings with it the challenge of raising productivity of the agricultural sector in the coming decades. Silvopastoral integration systems are an efficient alternative to reduce thermal discomfort, making it possible to increase animal production in a more sustainable way, without increasing the area. However, the insertion of the tree component in the system may be detrimental to the development of the forage, when poorly sized or managed, and the lack of information on the optimal spacing among the trees is one of the main difficulties in relation to the adoption of this management system. Thus, the objective of the present project is to develop a functional and structural model of plants capable of simulating the interactions that occur between the species inserted in the silvopastoral system, the productivity of the pasture and assist in the dimensioning of the spacing and direction of the tree roots. The model will be written in the rules-based XL (eXtensible Language) programming language in which routines will be implemented in GroIMP v 1.5 (Growth Grammar-related Interactive Modeling Platform) software, a three-dimensional modeling platform. It will simulate the development of pasture, using source-drain mechanisms, considering the effect of shading caused by the insertion of trees in the system. The model will be calibrated with data referring to the forage, arboreal component and photosynthetically active radiation readings previously collected in an experiment carried out in a silvipastoral area belonging to Embrapa Agrossilvipastoril. To evaluate the performance of the model and its possible limitations, it will be tested in three distinct edaphoclimatic conditions with different plant arrangements and silvopastoral system configurations. At the end of this project, it is expected to obtain a model able to simulate the competition for solar radiation that occurs in the system, the productivity of the pasture and that this tool can reduce uncertainties linked to this management system, helping in the dimensioning of the spacing and direction of the trees. (AU)