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Effects of plant density arrangement and nitrogen nutrition in navy beans

W. Thanomsub and N.J. Mendham

Department of Agricultural Science, University of Tasmania, Hobart TAS 7001

New early maturing Navy bean cultivars have shown high yield potential in Tasmania and are in demand for processing as ' baked beans' (3). The responses in seed yield and its components of two Navy bean cultivars to various plant densities, arrangements and nitrogen rates were investigated.


The experiments were conducted in 1989/90 and 1990/91 at the University Farm, 20 km from Hobart. The 1989/90 experiment comprised three densities by three rectangularities as main plots, with two cultivars as sub-plots, in two replicates. The 1990/91 experiment contained four supplement N levels as main plots, and three plant densities as sub-plots with three replications.

Results and discussion

The responses in seed yield and its components of the two Navy bean cultivars to various plant densities and arrangements were similar. Trends in seed yield favoured the highest density (up to 11%) and the square spacing (up to 17%) (Fig. la). At the lowest density (20 plants/m2) the effect of plant arrangement was marked, square spacing giving as high a yield as the highest density (60 plants/m2). Additional nitrogen prior to flowering increased seed yields signifi- cantly (Fig. lb) in each plant population by increasing the number of pods/plant. At low density 920 plants/m2), seed yield increased with increasing rates of N, but at plant densities of 40 and 60 plants/m2 there were no significant differences in seed yields with addition of 50, 100 and 150 kg N/ha. The overall results indicated that seed yield can be improved by use of higher densities, reduced rectangularities and higher nitrogen rates. These results are similar to the findings of (1), (2) and (4).

Figure 1. (a) Effect of plant density and arrangement on seed yield as mean of two cultivars; and (b) Effect of additional N and plant on seed yield as a mean of two cultivars density on seed yield. (1) and (2) indicate I.s.d. (0.05) for N rates at the same or different densities and densities at the same N rate, respectively.


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Thanomsub, W. and Mendham, N.J. 1989. Proc. 5th Agron. Conf, Perth, p. 654.

Wilkes, J.M. and Scarisbrick, D.H. 1974. J. Agric. Sci., Camb. 83, 175-176.

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