Summary: The average rice crop yields in this country are very variable owing to the particular demands and susceptibility to disease of rice. Crop failures due to different causes can be avoided by suitable. agrotechnical methods if we know the nature and extent of the relationship between the development of rice and the climatic conditions connected with the way of raising the crops.

The investigated area is an organic part of the natural landscape of the Southern Lowland. In a short analysis the pedological classification and the physical and chemical properties of the soil layers forming the surface in the region of Szarvas are described.

The development of the genetic soil types is described for smaller area units, because the connections between the parts can be demonstrated only within small units. In classifying the natural landscape of the Southern Lowland we are chiefly concerned, according to the purpose of our investigation, with analyzing the soil conditions of the Körös region and the loess table of the southern Trans–Tisza region.

For suitable growth of rice it is essential to ensure optimal or near-optimal soil temperatures. The soil temperature of the flooded rice field – owing to the good heat insulation and great heat capacity of the water mass – is about the optimum required for the development of the plant.

The diurnial fluctuation of the temperature of soil layers with different water covers and different depths decreases, in varying degrees, from June to September. This decrease is connected with the development and closing of the plant stand. With the formation of the panicle zone a large part of the light energy needed for the ripening of the grains is absorbed and utilized in the panicle zone, and thus less energy reaches the surface of the water or the soil. At the beginning of September, after the flooding water drained, the radiation penetrating through the panicle zone reaches the soil directly, and the surface of the soil is also in direct contact with the air. As a result of all this the amplitude of the diurnial variation of the temperature begins to grow again in the drying soil. After draining the flooding water, the effects of the changes in the moisture content and the temperature of the soil favour the full development of the plant and the ripening of the grains.

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