Low‑height castor bean row spacing and plant population for mechanical harvest

Abstract

The objective of this work was to evaluate the effect of row spacing and plant population on yield and others agronomic characteristics of low-height castor bean, for mechanical harvest, in the summer cropping season. The experiment was carried out during the 2007/2008 and 2008/2009 growing seasons, on a Haplorthox soil, in Botucatu, São Paulo State, Brazil, using the cultivar FCA‑PB. A randomized complete block design in a split-plot arrangement with four replicates was used. The plots consisted of four row spacings (0.45, 0.60, 0.75, and 0.90 m), and the subplots of four initial plant populations (25,000, 40,000, 55,000, and 70,000 plants per hectare). Increases in plant population, decreased plant survival, stem diameter, number of racemes per plant and number of fruits per raceme, regardless of row spacing. The highest grain and oil yields of castor bean FCA‑PB are obtained with initial plant populations between 55,000 and 70,000  plants per hectare, with the row spacing from 0.45 to 0.75 m.