Together with sugarcane, tensai - also known as sugar beets - are an important source of natural sweetener.

In contrast to sugarcane, however, which is a tropical crop, sugar beets can be grown even in cold climates and will accumulate sugar in high densities in their roots when the temperature drops.

In Japan, therefore, sugar beets can be grown only in Hokkaido, where they are supplied to sugar manufacturing plants as a raw material.

Because sugar beets can be raised in this manner even in a cold climate, in Hokkaido they are grown as a cold weather damage prevention crop to reduce damage from cold weather. Because sugar beets grow by putting out numerous leaves, however, they transpire large quantities of water and are extremely susceptible to drought damage.

In the Shari-Abashiri region in northeastern Hokkaido, the precipitation from April to September in an ordinary year is 351mm (66% of Sapporo), making it one district where drought can easily occur.

We therefore sought to understand actual drought conditions in this area and investigated the relationship between drought damage and soil conditions.

Using the LANDSAT/MSS observation on May 29, 1984 we sampled fields left in a fallow, unplanted state. We then classified the crops grown in the sampled fields and sampled the sugar beet fields by using the LANDSAT/MSS on August 1, 1984.

This approach enabled us to accurately select the fields used to grow sugar beets.

Next, we summed the sugar beet cultivation land area and harvest quantities for each individual farm household in the Shari-Abashiri region to use as the ground data, and calculated the unit land area yield volume for each producing estate.

We then created a multiple regression equation for these producing estate sugar beet field unit yield quantities and the DN for the August 1, 1984 LANDSAT/MSS, and used this multiple regression equation to create a map of the entire region.

In addition, we also examined the relationship between this 1984 drought sugar beet yield quantities map and the soil humus content calculated from the LANDSAT/TM data and an existing soil map.

The multiple regression formula coefficient for the August 1, 1984 LANDSAT/MSS DN and the yield per sugar beet unit land area in the field survey was 0.852.

From the regression formula obtained we were able to create a sugar beet damage distribution map, and we could understand the cultivation spatial distribution. In 1984, a drought year, we found that soil with a high humus content suffered from less drought damage.

By this research, an utility value to the agricultural disaster of the remote sensing data was recognized.

Ogawa S. and Miyama K.: An Examination of the Relationship Between Sugar Beet Yield and Soil types in the Shari-Abashiri District Using Satellite Data, Journal of the Japan Society of Photogrammetry and Remote Sensing, Vol. 34 No. 1, pp. 61-70, 1995

Ogawa S.: The Study of Regional Agricultural Information Using Remote Sensing, Research Bulletin of the Hokkaido National Agricultural Experiment Station, No. 167, pp. 1-68, 1998