Plant Population and Irrigation Effects on Spanish Peanuts (Arachis hypogaea L.)1

Both irrigated and nonirrigated conditions were imposed on various populations for three years using the peanut (Arachis hypogaea L.) cultivar Argentine. Row spacings were 0.25, 0.5, 0.75 and 1 m. Within-row plant spacings ranged between 2 and 27 plants/m. The dependent variables of yield (kg/ha and g/plant), other kernels (%) and net return ($/ha) were fitted with a surface response equation Y = β1 + β2X1 + β3X12+ β4X2 + β5X22+ β6X1X2, with X1 spacing between rows and X2 spacing between plants within the row. This model fitted all dependent variables very well for both irrigated and nonirrigated conditions. Resulting interpolation of the data using the above equation indicated that the 0.25 m row spacing gave the highest yield of unshelled peanuts for both irrigated and nonirrigated conditions. Approximately 15 plants/m was the optimal plant spacing (in all row spacings) for maximum yield and quality. Integrating yield and quality in terms of net returns, the 0.25 m row spacing was optimal for production of Argentine peanuts. Computations based on the above equation and evaluated at constant population density (plants/ha) showed yield was still increased to the narrowest row spacing in the study. Subsequently, row spacing vs. yield studies with Starr and Comet cultivars were conducted over seven growing seasons at a spacing in the row of about 10 plants/m. Row spacing varied from 0.15 to 1 m. In every year, the narrow spacings outyielded the wider spacings.