Indicators for assessing water, energy and labor use performance in a low-tech greenhouse

One of the advantages of controlled agriculture is the notable increase in crop yields. However, at high-tech levels, water use productivity has increased, while energy use productivity has decreased. Therefore, the objective of this study was to estimate water, energy and labor use productivity in tomato cultivation, for a low-tech greenhouse. The inputs used in the production process were recorded from April 24 (date of transplant) to October 16, 2016 (date of last harvest). The yields obtained were 19.07 kg∙m-2. Water use productivity was 27.86 kg∙m-3 (35.89 L∙kg-1), which is within the range reported for unheated plastic greenhouses (30-40 L∙kg-1). Energy productivity was 0.331 kg∙MJ-1, and the energy consumed per unit area was 57.61 MJ∙m-2, with Calcium nitrate being the input with the highest energy demand (49.49 %). During the production cycle, 738 working hours were used, 78 % of which were dedicated to cleaning and maintenance, with labor productivity of 3.02 kg∙h-1.