三亚市崖州区双季稻需水量与需求指数变化分析

Analysis of water requirement and requirement index variation of double cropping rice in Yazhou district,Sanya city

为更精确地掌握海南省三亚市崖州区双季稻生育期内的灌溉需求,为双季稻种植的灌溉水量分配提供参考依据。本研究基于三亚市2002—2022年逐日气象资料和当地早、晚稻种植区作物生长的统计资料,分析了当地参考作物蒸散量(ET_(0))、双季稻生育期内的作物需水量(ET_(c))、有效降雨量(P_(e))、净灌溉需水量(IR)和灌溉需求指数(IRI)的变化,采用P_(e)nman-Monteith公式和单作物系数法,并结合年际变化倾向率以及Mann-Kendall趋势检验法,分析了2002—2022年三亚市ET_(0)、双季稻ET_(c)和IR的时间变化特征。结果表明:2002—2022年三亚市ET_(0)为1 115.8~1 213.5mm,呈不显著的增加趋势,变化率为0.72 mm/a,年均ET_(0)为1 152.9 mm;早稻全生育期ET_(c)、P_(e)、IR分别介于399.5~448.3 mm、94.4~200.9 mm、205.5~353.0 mm之间,ET_(c)呈不显著的增加趋势,变化率为0.28 mm/a,IR呈不显著的减少趋势,变化率为-0.18 mm/a;晚稻全生育期ET_(c)、P_(e)、IR分别介于357.1~402.9 mm、266.1~422.7 mm、-65.7~126.2 mm之间,ET_(c)呈显著的增加趋势,变化率为0.78 mm/a,IR呈不显著的增加趋势,变化率为2.04 mm/a。早稻各生育阶段作物需水量变化趋势为:拔节孕穗>分蘖后>分蘖期>乳熟期>抽穗开花>黄熟期>移植回青,晚稻各生育阶段作物需水量变化趋势为:拔节孕穗>分蘖期>乳熟期>分蘖后>抽穗开花>黄熟期>移植回青。三亚市崖州区早、晚稻灌溉需求指数分别介于0.51~0.79和-0.18~0.32之间,年均IRI分别为0.67和0.09。由此可知,三亚市崖州区早稻对灌溉的依赖程度远远高于晚稻,仅依靠有效降雨无法满足作物生长的需求,易发生干旱缺水现象,需在生育期进行补充灌溉。

To master the characteristics of irrigation requirement during the whole growth period of double cropping rice in Yazhou district,Sanya city,Hainan province and provide a reference basis for irrigation water allocation in planting area,this study analyzed the changes of local reference crop evapotranspiration(ET_(0)),crop water requirement(ET_(c)),effective precipitation(P_(e)),net irrigation water requirement(IR),irrigation requirement index(IRI)based on the daily meteorological data of Sanya city and the statistics of crop growth in local early and late rice planting areas for the period of 2002—2022 by using the P_(e)nman-Monteith formula and the single-crop coefficient method and combining with the trend rate as well as Mann-Kendall trend test.The results showed that:the ET_(0) in Sanya city ranged from 1115.8 to 1213.5 mm,and showed a not significant increasing trend with trend rate of 0.72 mm/a and the mean value of ET_(0)1152.9 mm from 2002 to 2022.The ET_(c),P_(e),and IR during the whole growth period of early rice ranged from 399.5 to 448.3 mm,from 94.4 to 200.9 mm,and from 205.5 to 353.0 mm respectively.ET_(c) showed a not significant increasing trend with trend rate of 0.28 mm/a,and IR showed a not significant decreasing trend with trend rate of-0.18 mm/a.The ET_(c),P_(e),and IR during the whole growth period of late rice ranged from 357.1 mm to 402.9 mm,from 266.1 to 422.7 mm,and from-65.7 mm to 126.2 mm respectively.ET_(c) showed a significant increasing trend with trend rate of 0.78 mm/a,and IR showed a not significant increasing trend with trend rate of 2.04 mm/a.The crop water requirement of early rice at each fertility stage showed a trend of“jointing-booting stage”>“late tillering stage”>“tillering stage”>“milky ripening stage”>“heading and flowering stage”>“yellow maturity stage”>“transplanting and returning green stage”.The crop water requirement of late rice at each fertility stage showed a trend of“jointing-booting stage”>“tillering stage”>“milky ripening stage”>“late tillering stage”>“heading and flowering stage”>“yellow maturity stage”>“transplanting and returning green stage”.The irrigation requirement index of early and late rice in Yazhou district ranged from 0.51 to 0.79 and from-0.18 to 0.32 respectively,and a mean value of IRI were 0.67 and 0.09 respectively.It showed that early rice in Yazhou district relied on irrigation to a much greater extent than late rice,and that relying only on effective rainfall could not meet the needs of crop growth,and was prone to drought and water shortages,which required supplemental irrigation during the growth period.