Manejos de poda e desbaste de plantas para viabilização produtiva de pomar de nogueira-pecã em alta densidade comprometido pelo sombreamento

Abstract

High plant density has been used in several pecan orchards in southern Brazil. Due to lack of appropriate management of orchards and cultivars or dwarf rootstocks, shading has become a problem over the years. This study aimed at evaluating methods and periods of pruning and tree thinning as alternative management practices to improve fruit production and quality in high-density pecan orchards with shading problems. The study was carried out in a commercial pecan orchard in Santa Rosa, RS, Brazil. The study of periods was conducted in two production cycles – 2019/2020 and 2020/2021 – while the study of pruning methods was carried out throughout five cycles, from 2018/2019 to 2022/2023. The experiment had a randomized block design. Both hedge and central pruning methods were conducted by a motor pruner while tree thinning required a chainsaw. Vegetative, productive, qualitative and economic evaluations were carried out. Results showed decrease in shoot length after postharvest pruning and in the number of dry branches after central pruning and tree thinning. Besides, tree thinning increased vegetative growth, production, production efficiency and quality of pecans but it did not increase yield. However, hedge and central pruning resulted in increase in yield. Both pruning methods also increased fruit size and mass. Central pruning, followed by hedge pruning, was the treatment that gave the best economic response throughout the experiment. Hedge pruning also increases yield, but it is costly and does not decrease branch drying in trees. In general, tree thinning leads to high production and quality of fruit and decrease in branch drying; as a result, more branches are kept in the basal part of trees. Since central pruning increases yield, decreases the number of dry branches, improves fruit quality and, consequently, has the best benefit-cost ratio, it is the most interesting management practice in orchards with shading problems. The conclusion is that hedge and central pruning are the most interesting alternatives in the short term while tree thinning requires more time in terms of financial compensation.