Articles
PREDICTING PURSLANE (PORTULACA OLERACEA L.) HARVEST IN A HYDROPONIC FLOATING SYSTEM
Article number
898_25
Pages
205 – 209
Language
English
Abstract
The floating system is an easy and profitable growing technique for the cultiva¬tion of small-sized and value added vegetable crops.
In this paper, five simple methods were used to predict the optimum harvest date of baby leaf purslane based on daily maximum and minimum air temperatures.
The methods were chosen based on their performance as described in the literature for several vegetable crops.
The most reliable method was defined as the one with the smallest coefficient of variation (CV). The CVs were calculated for each method over two seasons and two years.
All heat unit methods had smaller CV and improved harvest date prediction accuracy than the standard method of counting days from sowing to harvest.
Autumn cycles were the largest (approximately two months), while the summer cycles were the shortest, being the purslane harvested in just 13 days.
The base temperature varied among seasons, being higher (6°C) for summer cycles than for autumn cycles (0°C). The best fits were obtained with the combination of a Tb of 0°C with a Ceiling of 34°C for summer and 28°C for autumn.
Incorporating radiation improved the model prediction accuracy.
Based on these results, the heat unit summation method recommended for this region is the reduced ceiling method considering radiation.
In this paper, five simple methods were used to predict the optimum harvest date of baby leaf purslane based on daily maximum and minimum air temperatures.
The methods were chosen based on their performance as described in the literature for several vegetable crops.
The most reliable method was defined as the one with the smallest coefficient of variation (CV). The CVs were calculated for each method over two seasons and two years.
All heat unit methods had smaller CV and improved harvest date prediction accuracy than the standard method of counting days from sowing to harvest.
Autumn cycles were the largest (approximately two months), while the summer cycles were the shortest, being the purslane harvested in just 13 days.
The base temperature varied among seasons, being higher (6°C) for summer cycles than for autumn cycles (0°C). The best fits were obtained with the combination of a Tb of 0°C with a Ceiling of 34°C for summer and 28°C for autumn.
Incorporating radiation improved the model prediction accuracy.
Based on these results, the heat unit summation method recommended for this region is the reduced ceiling method considering radiation.
Publication
Authors
J. Ochoa, D. Niñirola, E. Conesa, L. Lara, J. López-Marín, J.A. Fernández
Keywords
heat units, degree days, styrofloat, leafy vegetables, timing
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