Yield gaps and ecological footprints of potato production systems in Chile

In Chile, potatoes are grown in a wide range of ecological zones and levels of technology resulting in wide ranges of crop management and yields. The aim of the present study was to assess yield gaps, resource use efficiencies and foot-printing in different potato cropping zones between 18 and 53° South considering early and late crops, small and large holdings (>10 ha/year) and ware and seed potato crops. Two mathematical tools were used to generate data for comparisons: the light interception and utilization simulator for potato crops (LINTUL-Potato) to calculate potential yields and water need of each system and the Cool Farm Tool – Potato (CFT) to calculate the amount of CO2 associated with the production of 1 ton of potato. Meteorological data for LINTUL-Potato came from official services, and data needed to complete the CFT came from a survey carried out for the 10 sites yielding amounts of inputs and number of operations, potato yields and planting and harvesting dates. The survey yielded 20 cropping systems with an average yield of 31 t ha-1. Yields were related to daily growth rate and not to the length of the growing season. Considerable variation was found in resource-use efficiency and CO2 emission. It was concluded that large farms show a lower land footprint than small farms due to a higher technological level, but while applying more water and fertilizer, they result in higher water and CO2 footprints. Late crops may fetch higher off-season prices but have higher land, water and CO2 footprints. The most suitable potato production systems are the rain-fed summer crops in the South with the lowest footprints. The highest footprints have the irrigated winter crops in the centre of Chile. The subsistence high altitude Andean crop in the utmost North has the highest land footprint but the lowest CO2 emission. The description, analysis and benchmarking of the potato production systems in Chile allow strategies for improving footprints and profitability and yields information about future investments in research, development and production of the crop