To clarify the ability of dry matter production for field-grown mulberry pruned at various heights, the relationship between dry matter production and amount of intercepted radiation was investigated in a mulberry field. Two cultivars, ‘Senshin’ and ‘Shin-ichinose’, were planted in 2000. The experiment was conducted from 2001 to 2003. All experimental plots were pruned at the base in late May. ‘Senshin’ plots 50, 80, and 110 and ‘Shin-ichinose’ plots 50 and 110 were cut in early October at 50, 80, 110, 50 and 110cm height from the stumps, respectively. ‘Senshin’ plot 40/80 was cut in late July to 40cm in height and in early October to 80cm in height. The higher the cutting height became, the higher intercepted radiation became. After cutting in October, the amount of intercepted radiation was the most in the 40/80 plot of ‘Senshin’. The higher the cutting height became, the more the shoot yield during the experimental period became. The sum of three years' yield of young shoots of plot 40/80 in May and of leaves in July and October were as much as those of the 50 and 80 ‘Senshin’ plots. The higher the cutting height became, the more all dry matter production during the experimental period became, and a significant difference at the 5% level was detected in the ‘Senshin’ cultivar. Dry matter of the stump and root was also the highest in 110 plots. Dry matter of the stump and root of the 40/80 plot was more than those of the 50 and 80 plots. The relationship between the amount of intercepted solar radiation and dry matter increment in the experimental period was linear.

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Mulberry dry matter production and dry matter division in shoots and storage organs were simulated by numerical models with cultivar ‘Senshin’ grown in a field for three years. All experimental plots were pruned at the base in late May. Plots 50, 80, and 110 were cut in early October at 50, 80, 110cm height from the stumps, respectively. Plot 40/80 was cut in late July at 40cm height and in early October at 80cm height. Daily intercepted radiation and average temperature were variables in the dry matter production model. Differences between measured and estimated dry matter production by the model were less than 3% for all experimental plots. In the dry matter division model, dry matter division to newly developed shoots was represented as a function of the longest shoot elongation rate. Except for the 50 plot, the estimated values of the dry matter division were similar to the measured values. The dry matter division in storage organs in the 50 plot was underestimated remarkably due to overestimation of the dry matter division in shoots during the third year. Estimated dry matter weight of the storage organs by the model decreased slightly after spring sprouting in all plots and, before cutting in June, exceeded the weight at spring sprouting. The model estimated the weight of the storage organ decreasing steeply after the cutting in June. After the cutting in October, the model estimated rapid dry matter accumulation in the storage organs in 110 and 40/80 plots and slow accumulation in the 50 plot.

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