Analysis of yield and economical performance in greenhouse tomato in Uruguay with a systemic approach

Doctoral thesis abstract

Abstract

Knowledge about contributing factors to yield loss is essential for sustainable intensification of agriculture. However, promising ideas from crop scale research are not always successfully adopted by farmers. Further analysis are needed to understand the interactions between decision making at crop and farm level and the consequences for the performance of the farm system as a whole. This study aimed to: (1) identify strategies to reduce yield gaps in greenhouse tomato in south Uruguay; (2) analyze main factors affecting economic efficiency of tomato crop and their relation with farms’ characteristics, and (3) explore improvement trajectories through re-design processes at both crop and farm level focusing in: synergies and trade-offs between crop yield maximization and farming system improvement. Yield gap was explored by combining regional agronomic diagnosis and yield gap analysis. 110 tomato greenhouses within 23 farms during 2014/15 and 2015/16 were assessed. Scaling up was explored in five farms through co-innovation under ecological intensification framework. Yields ranged from 0.9 to 24.3 kg m^-2 and yield gap was 10.7 kg m^-2 or 44% relative to potential. Cumulated photosynthetic active radiation intercepted (PARINT) was the most correlated with yield. We analyzed two complementary ways of increasing yield: (1) modifying growth-defining factors to increase PARINT and (2) modifying growth-limiting and reducing factors responsible for the gap to attainable yield at a given level of PARINT. Economic efficiency variability among tomato crops was explained mainly by yield and sales prices, while farm type according to resource endowment was not highlighted. Considering the farm as a whole when re-designing more sustainable systems had higher economic impact than focusing only on the main crop. However, yield gap analysis of main crop inside a farming system re-design process allowed to prioritize problems at crop level and be precise to suggest crop management plans to overall systems improvements.