Mapping of Drought Risk for Timothy Meadow in the Tempoku Region

Abstract

This study was conducted to estimate the risk of timothy damage by drought occurrence in the Tempoku region. Available water at the surface was calculated from 1 May to 20 August based on soil physical properties and precipitation. “Drought days,” the number of days for which the available water at the soil surface was zero, from June 21 (the day after first cutting) through August 20 (the day of the second cutting), were counted each year during 2000-2009. During those 61 days for each of 10 years, the “drought risk” was calculated: the probability of 20 or more drought days. The drought days and drought risks were mapped using GIS software. Results show that both drought days and drought risks were different among plots in the Tempoku region, and even between neighboring plots. Especially when the soils were quite mutually different, large differences were found for drought days and drought risks. The estimated drought days can predict the timothy yield of the second cut at the Tempoku sub-station. This risk map can be adapted to actual farmers’ fields in the Tempoku region.