| Budget Amount *help |
¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 1988: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1987: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1986: ¥3,600,000 (Direct Cost: ¥3,600,000)
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| Research Abstract |
1.Measurement system to determine root characters (length, surface area, volume and mean diameter) was established through image processing; an error by the system is within 5%.
2. The root system of crops growing in the field was shallower in rice and potato, and was deeper in wheat and maize. The root density per unit soil volume as well as the distribution percentage in upper soil layers were larger in rice and wheat, and smaller in maize and potato.
3. The total length of roots per unit field area ranged 20-90 km/m^2, being longer in rice and wheat and shorter in potato. The total surface area was 80-110 m^2/m^2 in rice, wheat and maize, and only about 20 m^2/m^2 in potato. The total volume was in the range of 1.4-5 1/m^2, where it was larger in maize and smaller in potato. These values in rice, wheat and soybean decreased with nitrogen application, while those in potato increased.
4. The largest density of various root characters was larger in rice, while it was smaller in potato. Those values in rice decreased with nitrogen application, while that in sugarbeet increased.
5. Plants per se will require a limited size of rhizosphere, when an adequate supply of nutrients and water is available, such as in solution culture (e.g., 125 cm^3) as well as in soil culture (e.g., 400 cm^3) under favorable climatic condition. In the case of soil culture with limited rhizosphere size, however, fertilizer management was the greatest problem, once the climatic condition is unfavorable. Partition of fertilizer application will have an advantage to root development.
6. Plants grown in smaller beds made of rockwool and polyester was much smaller than those in larger beds; the range of bed size was 125-700 cm^3. It is suggested that there is a discrimination between nutrients and water in the flowing process in these materials.
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