Quantification and accumulation of cold hours and degree days in the Valle alto of Cochabamba

Abstract

The best peach producing zone in the department of Cochabamba is the high valley zone, despite the productive potential there is a lack of adequate information on important climatic elements for deciduous fruit trees such as the accumulation of "cold hours" (HF) "degree days" (DG), which are necessary to evaluate behavior, adaptation and introduction of fruit species and/or varieties. It was carried out a study on quantification of these parameters through the evaluation of mathematical models with the aim of establishing the most appropriate model, also to determine the accumulation of HF and DG in the study region. During the years 2017 to 2019, with meteorological information required by each quantification model, data from 50 years were used, which were provided by SENAMHI. Fourteen mathematical models were evaluated. The results show us that: The model proposed by Da mota (1979), considering the months of June to August and Crossa Raynoud modified, quantify a cumulative average value of 350 to 445 HF for the Region of San Benito. The Residual and Monteith Method, quantifying a range between 1200 to 1400 DG. The behavior of the accumulation of HF for decades, determines a decrease of up to 25% in the last 50 years, possibly as a result of climate change. Results were compared with phenology works and cold hour treatments, showing similar results, accumulating 350 HF in peach trees variety Gumucio Reyes and apple tree variety Princesa. These mathematical models selected in the study, provide us with a data of HF and DG reference, so there are models of quantification appropriate to our climatic conditions, the models can be used in other regions to calculate these important variables in deciduous fruit culture.