灌溉次数和施肥量对甘肃引黄灌区紫花苜蓿种子产量的影响

摘要

甘肃引黄灌区根据农作物对水分的需求，通常在每年固定时期给水灌溉。本试验研究了甘肃引黄灌区不同灌溉次数（2，3，4次）和磷酸二铵施用量（0，180，360，540 kg／hm2）对紫花苜蓿种子产量及产量构成因素的影响，旨在寻找该地区紫花苜蓿种子生产的合理灌溉次数和最佳施肥量。通过两年的研究发现，灌溉次数对紫花苜蓿种子产量具有极显著影响（P ＜0．01），灌溉次数增加反而降低种子产量，2次灌溉对紫花苜蓿种子生产较为适宜，两年的平均值分别为686和891 kg／hm2；种子产量随着施肥量的增加，呈现先升高后降低趋势，在施用360 kg／hm2肥量条件产量最高，两年的平均值分别为631和786 kg／hm2；灌溉次数和施肥量二者交互作用显著，在2次和3次灌溉条件下，施肥量增加显著提高种子产量；在4次灌溉条件下，随着施肥量增加呈现先上升后下降趋势；在2013年，2次灌溉、360 kg／hm2施肥量条件下的种子产量最高，为757 kg／hm2；在2014年，2次灌溉、540 kg／hm2施肥量条件下的种子产量最高，为1019 kg／hm2；苜蓿种子产量与单位面积生殖枝数、结荚花序数呈现显著正相关，相关系数分别为0．503和0．835；2次灌溉、360 kg／hm2磷酸二铵施肥条件为该地区较为经济、高效的灌溉和施肥条件。%Given crop demand for water in the Yellow River irrigation region of Gansu province,irrigation needs to be supplied for fixed periods.To explore optimum irrigation strategies and fertilizing methods,the effects of different irrigation frequencies (two,three and four times)and application rates of phosphate diamine (0,180, 360,540 kg/ha)on alfalfa seed yield and yield components were studied.The results showed significant differ-ences in seed yield for the different irrigation frequencies (P <0.01).Seed yield decreased with increased irriga-tion frequency.Irrigating two times was suitable for local alfalfa seed production,with the average yields in 2013 and 2014 being 686 and 891 kg/ha respectively.With increased fertilizer rates,actual seed yield first in-creased and then decreased,with the highest yields achieved under a fertilizer rate of 360 kg/ha (average yields in 2013 and 2014 were 631 and 786 kg/ha respectively).Irrigation frequency and fertilizer rate interacted in terms of alfalfa seed yield.Under two-times and three-times irrigation,increasing fertilizer rates could improve seed yield significantly.Under four-times irrigation,with increased fertilizer rates the seed yields first in-creased and then decreased.In 2013,the highest actual seed yields (757.28 kg/ha)were obtained with two-times irrigation and a fertilizer rate of 360 kg/ha.In 2014,the highest actual seed yields (1018.75 kg/ha)were obtained with two-times irrigation and a fertilizer rate of 540 kg/ha.Alfalfa seed yield had significant correla-tions with effective fertile tiller number (R 2 =0.503)and inflorescence number (R 2 =0.835 ).In summary, two-times irrigation and a fertilizer rate of 360 kg/ha are recommended for local alfalfa seed production.