Study On Agrometeorological Service For Sunflower Production In Hetao Irrigation Area

In order to expand the weather service effectively, and resolve the problems concerning the agro-meteorology of the local sunflower production, based on statistic methods and geographic information systems, the suitable sowing date, the agricultural meteorology disaster and pest, the whole growth stage weather conditions and the suitable irrigation date were analyzed. The suitable planting regions for sunflower have been quantitatively plotted out, and the forecasting models were also established in this study.The optimal sowing dates and the index of meteorological conditions for edible and oilseed sunflower cultivars were identified. The optimal sowing dates for edible cultivar of sunflower is between April 6th and April 30th, and for oilseed cultivar of sunflower is between April 19th and May 16th. For the edible sunflower, the primary index of forecasting sowing date is the first day which the air temperature is steadily above 5℃; For oilseed sunflower planting, the primary index of forecasting sowing date is the first day which the air temperature is above 10℃in this areas steadily.The idiographic agrometeorology indexs were established by the meteorological factors which influence the sunflower growth in seven growing periods obviously, namely sowing, three leafs, alternate leaf, squaring, bloomflorescence, blossom end and maturity.Spring frost is the mainly agrometeorological disaster which influence the sunflower growth in this area. While it has no obvious influence on the sunflower grouth with high tempreture. The main index of the spring frost is the minimum temperature on the ground. The index of light frost is the minimum temperature≤1℃on the ground, and the index of heavy frost is the minimum temperature≤-1℃on the ground.The optimal irrigation time and period for sunflower were designed. The 4 suitable irrigation days for edible sunflower are 30 days after emergence, squaring, before blossoming out and grain-filling, and 3 suitable days for oilseed sunflower are 30 days after emergence, squaring and before blossoming out.The sunflower rust diseases in this area usually occur in following periods. First one is the next periods of ten days when precipitation exceed 10 mm in a period of ten days, or the rainy days of a period of ten days were more than 5 days. Second one is the next 2-3 days when precipitation exceed 10 mm or rainy days were more than 5 days during the ten days.The rust disease occurs early, and then, the prevalence of the disease is more possible. The loxoszege stictialis will develop when temperature is lower than 23℃, otherwise, it will be restained when the temperature is higher than 23℃.The Hetao irrigation area can be divided into 4 suitable districts for sunflower planting, they are the best suitable, more suitable, suitable and basic suitable districts.In this study, the outline of meteorology service was presented. This outline included forecast and analysis context as well as timetable of these services.