施氮水平和方式对王草生产特性和品质的影响

Effects of different N feritilization modes and rates on the production and quality of king grass

盆栽的试验条件下,研究不同施氮量和施氮方式对王草(Pennisetum purpureum×P.typhoideum)产量和品质的影响。结果表明,氮肥对王草的生产和品质有显著的促进作用,王草的干质量、株高、叶绿素SPAD值、含氮量和粗蛋白含量都与施氮量呈正相关,全磷、全钾、粗纤维含量与施氮量呈负相关。氮肥施用时期对产量和蛋白质含量的效应并不同步,同一刈割期内,同一施氮水平,在生长初期、分蘖期、拔节期分3次施入优于生长初期一次性施入,利于王草粗蛋白含量的提高,且只有分3次平均施入对干草产量影响显著(P<0.05)。王草生长的最佳盆栽施氮量为3.48g.盆-1(纯氮180kg.hm-2),施氮量为1.74～6.95g.盆-1(纯氮90～360kg.hm-2)时王草能正常生长,小于0.87g.盆-1(纯氮45kg.hm-2)或大于13.91g.盆-1(纯氮720kg.hm-2)对王草生长有限制,不施肥显著限制生产。在本试验条件下,最好的王草施肥方式是在生长初期、分蘖期和拔节期分3次平均施用。

In order to provide the reference about nitrogen rational use in king grass （Pennisetum purpureum × P. typhoideum）production, effects of different nitrogen levels and application methods on king grass growth and quality were studied by using pot culture experiment. The results indicated that N could im- prove yield and quality of king grass remarkably. The dry weight, plant height, the chlorophyll SPAD val- ue, nitrogen （~） and crude protein contents （~） of the king grass had positive correlation with N applica- tion. The contents of phosphorus （%）, potassium （%） and coarse fibre （%） had negative correlation with N application. The effect of N application at different periods on yield and crude protein content was not synchronization. Application N three times at different growth periods instead of one time at the beginning of growth period could remarkably increase the crude protein content. Further more, only application N three times with equal amount at different growth periods could conspicuously improved the dry weight of king grass. The most suitable N amount for king grass in our experiment was 3.48 g · pot-1 （about 180 kg. ha-1 nitrogen）. However, between 1.74-6.95 g · pot-1（90-360 kg·ha-1）the king grass could grow normally, less than 0.87 g·pot-1 （45 kg·ha-1 ）or more than 13.91 g·pot-1 （720 kg. ha 1）the growth was restricted; and no fertilization the growth was seriously retarded. Thus, the best fertilization way of king grass is to fertilize N with equal amount at stages of initial growth, tillering and jointing.