Plant Population Density

In trials in the U.S., planting distances of between 30.5 cm (12 in.) and 91 cm (36 in.) were examined within rows that were 1.5 m (5 ft) apart. Closer plant spacing within rows increased yields per unit area, with 61 cm (2 ft) recommended as optimal. Increasing plant spacing from 30.5 to 61 cm increased mean tuber size, but spacings over 61 cm had no further effect on tuber size. Larger tops and increased number of tubers occurred at spacings of 61 cm and over (Boswell et al 1936). 

Researchers in Spain found that the optimum density for highest tuber yield was between 30,000 and 40,000 plants ha with rows separated by about 80 cm and a plant spacing of around 36 cm, when irrigation and fertilization were deployed. At higher plant densities (50,000 plants ha ), fertilization significantly increased yield, although at lower plant densities fertilization only had a marginal or no effect on yield (Fernandez et al., 1988). 

In experiments in Korea, using row widths from 30 to 90 cm and within-row planting distances from 5 to 75 cm, it was found that highest tuber yields were obtained with 50 to 70 cm between rows and 15 to 30 cm between individual plants in each row. It was concluded that the best spacing for Jerusalem artichoke was 70 by 30 cm—equivalent to 47,620 plants per hectare (Lee et al., 1985). 

Biology and Chemistry of Jerusalem Artichoke Helianthus tuberosus L. 

Intercropping rarely works with Jerusalem artichoke because of its vigorous and tall growth. The closed foliage canopy suppresses intercrops as effectively as competing weeds. The exception is maize (Zea mays L.), a tall crop that benefits from soil and climatic conditions similar to those of Jerusalem artichoke (Riotte, 1978). However, this intercrop combination is rarely utilized. 

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The quantity of tubers required to plant a hectare depends upon their size and the plant population density. Using 50 g of seed pieces, plant spacings of 30 x 100, 50 x 100, 50 x 70, and 100 X 100 cm require a minimum of 1,666, 1,428, 1,000, and 500 kg, respectfully. 

The presence and degree of branching vary with clone, plant population density, and photoperiod (Pas ko, 1982). Individual clones (160) differed in their branching habit (e.g., nonbranched, intermediate, extensive). The absence of branches on the main stem is relatively rare. In branched clones, lateral branches are formed, starting at the base of the plant, in the axils of the leaves, generally... 

Plant population density affected the amount of respiratory losses at the highest density (10 x 10 cm), the total respiratory losses increased markedly in June. At the lower densities (20 x 20... 

Neighboring communities and plants. Population density and proximity to the plant should be considered for the initial site and in anticipation of a possible future expansion. 

Schlotzhauer, W.S., E.B. Higman, and I. Schmeltz Products from pyrolysis of tobacco extracts in The chemistry of tobacco and tobacco smoke, edited by I. Schmeltz, Plenum Press, New York, NY (1972) 69. Schlotzhauer, W.S., M.J. Kasperbauer, and R.F. Severson Plant population density effects on the alkaloids, solanesol and chlorogenic acid content of burley tobacco Tob. Sci. 33 (1989) 47-51. 

Plant population density scales as the same as for animals (Enquist et al., 2000). Densities of both plants and animals are dictated by the rate of resource supply. When the plant density and... 

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