黑龙港流域典型地区6-9月水热变化特征.

【Objective】The present paper aimed to explain the changes of hydrothermal resources in the growth period of foxtail millet and maize in Heilongjiang region, and to provide theoretical basis for crop safety production.【Method】Based on the daily weather data from 1957 to 2013 in Raoyang County and Penman-Monteith formula, precipitation anomaly percentage and growth length day（GDD）, this paper analyzed the changes of hydrothermal resources in Raoyang County from June to September.【Result】（i） The size of ET0 was June > July > August > September, and the climatic tendency rates were-5.85,-1.96,-2.59 and-1.46 mm 10 a-1, respectively. The decrease of ET0 in different months was affected by different ten days, June was mainly affected by mid-late days, July was affected by mid-late days, August and September were affected by early and mid-late days, respectively.（ii） The frequency of drought from June to September was 33.33 %, 19.30 %, 31.58 % and 38.6 % respectively. Light drought was dominant in June and July, light drought was dominant in August and moderate drought was dominant in September.（iii）From June to September, the growth degree days were 459.58, 516.49, 470.40 and 301.64 ℃·d, respectively. The climatic tendency rates were 1.19, 3.28, 0.46 and 3.10 ℃·10 a-1, respectively. The increase of growth duration in June and August was affected by the first and middle ten days, July by the first and second ten days, and September by all stages, with the greatest increase in the latter ten days. 【Conclusion】In the future interannual changes, for crops such as millet and maize growing in Heilonggang from June to September, the heat resources were abundant and increasing, but the drought risk will increase in July and August. Therefore, in agricultural production, we should improve the irrigation system in July and August, and strengthen the measures of water conservation and drought resistance in this stage. [ABSTRACT FROM AUTHOR]