海侵地区不同降雨条件下海水灌溉‘油葵G101’的研究

EFFECTS OF IRRIGATION WITH DILUTED SEAWATER ON ‘OLEIC SUNFLOWER G101’ GROWN IN SALINIZED SOILS, LAIZHOU, CHINA

在对油葵(Helianthus annuus)室内海水砂培试验研究油葵耐海水生物学特征的基础上,为获取半干旱海侵区海水大田灌溉的技术参数,以指导当地大田海水灌溉的实际应用,2002(干旱年)、2003年(丰水年)在山东莱州受海水入侵最严重的半干旱地区进行了不同浓度海水补充灌溉油葵G101'的田问小区试验,着重研究了当地不同雨水条件下在油葵始蕾期、始花期海水灌溉两水的模式对夏播油葵产量结构及其主要形态指标、植株体内离子分布规律的影响.结果表明:1)在当地的土壤条件下,无论是干旱年份(2002年),还是丰水年份(2003年),在油葵生长期内(约100 d),补充灌溉两水,40%比例的海水灌溉是夏播油葵保证一定经济产量的安全指标,在干旱年份,海水比例超过40%时,油葵籽产量即显著下降,而在丰水年份,即使用60%比例的海水灌溉,油葵籽产量与40%处理也无显著差异.综合考虑油葵经济产量、节省淡水用量等因素,40%海水补充灌溉两水可视为该海侵地区灌溉油葵适宜的海水补充灌溉额度.2)干旱年份,20%海水灌溉处理下,初花期油葵除茎秆直径和葵盘鲜重外,其它各生理生态指标与淡水灌溉处理无显著性差异(p=0.05).而在丰水年份,即使用40%的海水灌溉,‘油葵G101’主要形态指标与淡水灌溉也无显著差异.3)0～40%比例海水灌溉处理,夏播油葵叶片能保持相对较高的Ca2+、Mg2+含量,而根系吸收的K+向葵盘的选择性运输能力很强.Na+主要积累在根部、茎部,而叶和葵盘中含量较低.Cl-在茎中含量最高.

Nearly half the irrigated fields in the world are becoming saline and alkaline. Soil salinization is becoming a serious problem in China, especially in the seashore plain of north China where there is a highly developed industrial and agricultural economy and a huge population. With the high speed of industrial development and rapidly increasing population, groundwater overuse is leading to an influx of seawater and further expediting salinization of freshwater resources and soil. Lack of freshwater is a main factor restricting social and economic development in the seashore plain of north China. Irrigation of crops with diluted seawater has been proposed as a way to conserve freshwater supplies. This experiment was conducted to studv the characteristics and effects of irrigation with diluted seawater on a salt tolerant economic plant and provide recommendations for saline water irrigation in these drought/semi-drought seashore areas.‘Oleic sunflower G101 ＇ （ Helianthus annuus ）, a sah-tolerant economic plant, was irrigated with different proportions of diluted seawater in the Laizhou, Shandong Province, where seawater intrusion is a very serious problem. The effects of irrigation with diluted seawater on various growth indices, the accumulation and distribution of ions in the plant, and total yields of ‘G101＇ planted under local rainfall conditions were investigated during two growing seasons, 2002 （drought year） and 2003 （wet year）. The sunflower was irrigated twice during the growing season, one at early bud and the other at early florescence. The results showed that 1） In both the drought year （2002） and the wet year （2003）, a 40% seawater irrigation solution was a safe dilution ensuring economic yields for the 100 day growth period of ‘G101 ＇ During the drought year, ‘G101＇ seed yields decreased significantly when irrigated with 40% seawater or greater, while there were no differences in seed yields in the wet year when irrigated with 40% or 60% seawater . Thus, irrigation with a 40% seawater solution was economically feasible. 2） During the drought year, most growth indices of oleic sunflowers when treated with 20% seawater were not significantly different with that irrigated with freshwater （p =0. 95）, except for stem thickness and disc fresh weight during early florescence. However, in the wet year, all measured growth indices were not significantly different from the freshwater treatment when treated with up to 40% seawater （p = 0.95）. 3） When irrigated with 0-40% seawater, Ca^2＋ and Mg^2＋ homeostasis was maintained in the leaves and root K^＋ selective ion transport to the disc was strong. Accumulation of Na^＋ was mainly in the root and stem, while Na^＋ concentrations in the leaves and disc were lower. Chloride content was the greatest in the stem as compared to other parts of the oleic sunflowers.