Abstract
We studied the water consumption of ‘Kyoho’ grape at each growing stage to develop a simple and practical irrigation program for the soil-mound rhizosphere restricted culture in a plastic house to reduce the load on the environment. It was considered that any management by tensionmeters would be difficult due to the uneven water content in the soil-mound and the large fluctuation in the water content depending on the location of the tensionmeters in the plastic house. A correlation of y = 0.250x was observed between the solar radiation intensity (x: MJ·m−2·day−1) and water consumption (y: L·day−1/tree). Average water uptake (AWU) per m2 leaf area on fine days was 1.3 L at flowering, 1.0 L as the berry enlarged, and 1.3 L at the ripening stage, respectively. AWU did not differ in relation to the growth stage on cloudy/rainy days. Suitable amounts of daily irrigation were investigated. By controlling the daily irrigation based on the water consumption of the grapes and the amount of solar radiation, annual irrigation could be reduced by 46 to 47% of the conventional irrigation method based on the tensionmeter, proving the efficiency in lowering the load on the environment while producing high quality grapes.
