Ary Apparecido Salibe

Relações entre a produção de laranjeira 'Westin' e as precipitações em Botucatu, SP

4 RESUMO - O trabalho estuda a correlaAao entre a produAao de um pomar de laranja, plantado no altiplano de Botucatu, SP, com as precipitaAies que ocorrem dezesseis meses antes da colheita e a idade do pomar. As plantas eram de laranjeira doce (Citrus sinensis (L.) Osbeck), variedade Westin, de clone nucelar, enxertadas em porta-enxerto de limoeiro eCravoi (Citrus limonia Osbeck), plantadas em solo Terra Roxa Estruturada, a 810 m de altitude e em regiao de clima do tipo Cwb. A cultura foi conduzida de modo convencional e sem irrigaAao. Coletaram-se dados de produAao, nos perIodos entre o 3o e o 17o e entre o 21o e o 27o ano de idade do pomar, para anAElise do comportamento da produAao e o efeito da idade e das precipitaAies na produAao. Calcularam-se equaAies lineares mœlti- plas de regressao, entre a produAao, idade do pomar e as precipitaAies mensais, nos perIodos de pomar juvenil, adulto, senescente e adulto-senescente. A produAao correlacionou-se com a idade e com valo- res mensais de precipitaAao. Os pequenos desvios observados entre os valores medidos e estimados de produAao revelaram que as equaAies de regressao poderiam ser usadas na previsao de safra ou no controle de irrigaAao suplementar do pomar. ABSTRACT - This paper deals with the existence of correlation between the production of a sweet orange orchard, planted at the plateau of Botucatu, Sao Paulo State, Brazil, with the orchard age and the rainfall that occurred in the sixteen months before the picking season. The plants were of sweet orange trees (Citrus sinensis (L.) Osbeck), variety Westin, budded on eRangpuri lime (Citrus limonia Osbeck) rootstock, grown on iTerra Roxa Estruturadai soil, at an altitude of 810 m above sea level and in a region with Cwb climatic type. The orchard was conducted by conventional ways and no irrigation was applied. The production of the orchard was recorded, during the period from the 3 rd until the 17 th and from the 21 st until the 27 th year old, to analyse the behaviour of the production and the effect of the orchard age and of the rainfalls on the production of the plants. Multi linear regression equations among the production, age of the orchard and monthly rainfalls were calculated for the juvenile, adult, senescent and adult-senescent phases of the period of orchard production. The produc- tion was found to be correlated with the orchard age and with the monthly rainfalls. The small devia- tions between the measured and calculated values of production showed that the regression equations could be used to crop forecast or to suplemental irrigation control of the orchard.