Resource use efficiencies as indicators of ecological sustainability in potato production: A South African case study

• Published in: Field crops research 2016-12, Vol.199, p.136-149
• Main Authors: Steyn, J.M., Franke, A.C., van der Waals, J.E., Haverkort, A.J.
• Format: Article
• Language: English
• Subjects: Agricultural input; Agro-ecological zones; Carbon footprint; Competitiveness; Crop model; Yield gap analysis; Yield potential
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2016.09.020

•Actual yields were on average 60% of potential yield, suggesting fairly efficient use of available resources.•Water, seed and nutrient use efficiencies differed widely between and within regions.•Fertilizers (34%) and irrigation (30%) contributed most to energy use.•Resource use efficiencies provided useful indicators of production sustainability in potato.•Use of decision support systems can help to improve efficiencies on individual farms. Potato, the most important vegetable crop in South Africa, is produced in many distinct geographical regions differing in climate, soils, production seasons and management practices and access to markets. These differences affect the amount of input resources required to produce potatoes as well as yields and crop value, and therefore the use efficiencies of land, water, nutrients, seed and energy. Resource use efficiencies affect the ecological and financial sustainability of potato production in this region, which has in general less favourable potato growing conditions than north-western Europe and the U.S.A., where high resource use efficiencies are usually recorded. This study aimed to assess and benchmark South African potato production regions, representing a wide range of growing conditions, regarding their use of input resources and to identify resource-intensive practices, which may suggest inefficient use of inputs. Surveys were conducted in 2013 and 2014 by interviewing growers in all production regions, to provide data on resource use efficiencies. Quantitative modelling approaches were applied to calculate carbon footprints as a proxy of energy use efficiency, potential crop yields and irrigation needs for each region. Variability in the gap between potential and actual yield was used to identify yield limiting factors. Actual yields achieved were on average 60% of the potential yield, suggesting fairly efficient use of available production factors. Water, seed and nutrient use efficiencies differed widely between and within regions and were not directly proportional to water requirements and yields achieved. Fertilizers (34%) and irrigation (30%) were the greatest contributors to energy use in potato crop production. Energy required to pump water was strongly related to the amount of irrigation applied, pumping depth and distance. Long distance travel of produce to retail points contributed substantially to energy use. Significant improvements in efficiencies are possible by improving management practic