Morphology, growth and yield of black oats cultivated in agroforestry systems in southern Brazil

Abstract

Agroforestry systems have emerged in agriculture as a more sustainable alternative to food and energy production and environment conservation, characterized by the coexistence of two or more species in the same cultivation area. Thus, this study aimed to assess the dynamics of solar radiation, radiation use efficiency, growth and productivity of black oats grown in agroforestry systems and in two crop years. For these ends, the study was conducted in the field in southern Brazil, in two growing seasons (2017 and 2018). The studied species were: Schizolobium parahybae, Peltophorum dubium, Parapiptadenia rigida, Eucalyptus urograndis. Samples were collected at different points in the understory and parameters evaluated were: absolute and relative growth rates, net assimilation rate, leaf weight ratio, leaf area ratio, specific leaf area, transmissivity of solar radiation, radiation use efficiency, crude protein content and the productive performance of black oats. The dynamics of solar radiation was modified by the canopy characteristics of the trees, with the highest transmissivity values obtained in the understory of Parapiptadenia rigida. Higher levels of shading reduced growth and yield, increased the radiation use efficiency, the number of stomata on the leaf surface and the crude protein content of black oats. The productive performance of black oats was significantly influenced by the forest species and crop years, with the highest productivity obtained in the P. rigida understory and in the crop year 2017. Based on the information generated in this study, the cultivation of black oats under P. rigida is highly recommended.