北疆地区棉花作物需水量时空演变及其气象影响因子

基于北疆25个气象站1961—2013年的气象资料和棉花生育期资料,利用 FAO 推荐的 Penman-Monteith 公式及作物系数法,对棉花各生育阶段的作物需水量和灌溉需水量进行估算.结果表明: 过去53年,北疆地区棉花需水量在各个生育期总体呈下降趋势,其中,花铃期作物需水量下降趋势最为显著,变化率为-0.15 mm·a^-1;各生育期内存在多尺度的周期变化,其中在30年左右的大周期尺度上,各生育期作物需水量大致呈现“偏高-偏低-偏高”的变化过程,在15～17年的中周期尺度上,经历了“偏低-偏高-偏低”的变化过程,而在较小年际尺度上,作物需水量无明显的周期特征;在空间分布上,作物需水量、灌溉需水量和水分盈亏指数多年均值总体上大致呈现自西向东递减的分布特征;突变结果显示作物需水量在各生育期均呈显著减少趋势,且在北疆西北和西南地区最为明显.各个生育期内,棉花需水量与平均风速、日照时数和平均气温都呈显著正相关,与相对湿度呈显著负相关.研究结果可为北疆棉花适时定量灌溉和提高水分利用效率提供基础数据支撑.

Spatio-temporal variation of water requirement and meteorological impact factors of cotton in North Xinjiang,China.

Based on daily data of 25 meteorological stations in North Xinjiang during 1961-2013, the FAO Penman-Monteith equation and crop coefficient method were used to estimate water requirements as well as irrigation water demands of cotton during all growth stages. The results suggested that cotton water requirement in each growth period had been decreasing in the past 53 years. Besides, crop water demand declined most significantly at the blossing and boll-forming stage, with change rate of -0.15 mm·a^-1. Furthermore, there were various multiscale cycle changes during the growth period. the water demand of crops in each growth period roughly changed as ‘high-low-high’ in the large periodic scale around 30 a and, as ‘low-high-low’ in the 15-17 a of the mesoscale cycle, but had no obvious cyclical characteristics on the interannual scale. Average crop water demands decreased roughly from west to east across North Xinjiang. The mutation results showed that the crop water demand decreased significantly in each growth period, especially in the northwest and southwest of North Xinjiang. In addition, cotton water demand was positively correlated with ave-rage wind speed, sunshine hours and average temperature during each growth period, and negatively correlated with relative humidity. The results would provide basic data for timely quantitative irrigation and improving water use efficiency of cotton in North Xinjiang.