沙土地夏玉米灌溉方式的试验研究

A Study on the Irrigation Way of Summer Corn i n Sandy Soil

在豫北耕作层保水能力较差的砂壤土地带，围绕节水和增收，开展了夏玉米沟灌、常规畦灌及减少生育期内灌水次数的试验研究，每次畦灌定额控制在６３０～６８２．５ｍ３·ｈｍ－２，而沟灌条件下平均灌水量仅为４４２．５ｍ３·ｈｍ－２。研究结果表明，反映夏玉米生长速率的株高、叶面积指数等性状均是以抽雄期为界，之前增长迅速；抽雄时植株高度达２．５０ｍ左右，之后增长速率明显减慢；而抽雄至灌浆初期，叶面积指数保持在５．４０～５．９２的最高值，往后急剧地下降。不同灌水处理下生长速率的变化则是随着供水总量的增加呈同步增长趋势。在干旱年份，畦灌夏玉米全生长期耗水４２７８ｍ３·ｈｍ－２，沟灌及减少灌水次数的处理，耗水量分别为３７６２ｍ３·ｈｍ－２和３３４８ｍ３·ｈｍ－２。按生长阶段比较，抽雄～开花期日耗水强度最大，为６６．７５～７６．５０ｍ３·ｈｍ－２；其次是拔节～抽雄期，平均为６５．５０ｍ３·ｈｍ－２；播种～出苗期间日耗水强度仅为１３．３５ｍ３·ｈｍ－２。不同的灌溉方式与灌水量对夏玉米的穗粒重、千粒重及粒占穗重的百分比都有影响。对于宽行稀植作物采用沟灌方式，灌溉用水量小（平均为４４２．５ｍ３·ｈｍ－２），所供的水能集中于植株的根际附近，?

For saving water and increasing yields an experimental study on furrow irrigatio n, border irrigation and reducing irrigation times during summer corn's growing period was conducted in the sandy loam region with poor preservation of soil moi sture in North Henan. Irrigation water quota under border irrigation was 630￣682 5 m 3\5hm -2 , while that under furrow irrigation only averaged 442 5 m 3\5hm -2 . The results show that the growing rate of plants height and l eaf area ind ex of summer corn increase rapidly before the tasselling stage, plant of height reaches about 2 5 m at tasselling time, then the growing rate slows down obviou sly. The leaf area index remains at the highest value of 5 40￣5 92 from the ta sselling stage to the initial stage of grain filling, then decreases sharply. Un der different irrigation treatments, the plants height and leaf area index inc rease with the total application of water. In dry years, water consumption of summer corn in whole growth period under bord er irrigation was 4 278 m 3\5hm -2 , that under furrow irrigation and i rrigation treatments with water amount reduced was 3 762 m 3\5hm -2 a nd 3 348 m 3\5hm -2 respectively. Daily water consumption from the tasselling stage to flowering stage was the biggest, it was 66 75￣76 50 m 3\5hm -2 ; from jointing stage to tasselling stage that was 65 50 m 3\5hm -2 and fr om sowing to seedling that was only 13 35 m 3\5hm -2 . Grain weight per e ar, 1 000 grain weight and the ratio of grain weight to ear weight were affected by various irrigation methods and water amount of irrigation. Compared with border irrigation, furrow irrigati on which was used for crops sparsely sown in wide rows, has more advantages stat ed as follows:① water use for irrigation being less (442 5 m 2\5hm -2 in average), ② irrigation water collecting around the root system of plants and i ntrarow evaporation being low, ③ grain weight per ear and 1 000 grain weight be ing high and yield reaching 9 616 5 kg\5hm -2 , and ④ it saving irrigation water by 22 8% and raising water productivity by 16 9%. During the growing pe riod of summer corn, a reduced number of irrigation times easily results in a gr eat loss of yield (13 7%). Therefore, precaution must be taken to prevent water stress caused by water shortage in dry years.