氮肥对红三叶和鸭茅草地生产性能影响的研究

本文对红三叶和鸭茅单、混播草地对施氮肥的反应情况进行了研究，发现氮肥对鸭茅的株高、分蘖及产草量具明显的促进作用，而红三叶对氮肥的反应则不十分明显。同时施肥后，单播处理牧草的产量增幅比混播处理大。试验结果还表明，鸭茅和红三叶产量与施氮肥量均呈指数关系。通过对单播鸭茅和混播草地总产对氮肥的反应规律进行分析，可以把混播草地对氮肥的利用情况及氮肥对该草地中红三叶固氮作用影响的变化规律分为３类：第１类为混播草地投入最低氮肥量，草地生产力较低，此时红三叶能提供较高氮素价值量；第２类，混播草地投入中等氮肥量，草地生产力中等，但红三叶提供氮素的价值量减小；第３类，投入较高氮肥量，但红三叶失去提供氮素价值。本试验显示，从经济效益角度考虑，对混播草地以少施氮肥为好，特别是在０～０．３ｔ／ｈａ范围内较为适宜。

The Influence of Nitrogenous Fertilizers Applied on Productive Performance of Red Clover and Orchardgrass grassland

After our study on the application of nitrogenous fertilizers & their reaction condition in the planting trial of Red Clover and Orchardgrass on mixture grassland,the author discovered that prominent and promotive reaction was appeared to the tillering status and grass yield,while the reaction of nitrogenous fertillizer to Red Clover was not very prominent. And at the same time, after fertillizer application,the range of variation in the single sowing treatment in forage plant was higher than that in mixture planting treatment. The trial result also indicated that the relationship between yields of orchardgrass and red clover mixture planting and N-fertilizer applying amount showed to us an exponential function. Through the analysis of total yields of single-seeded orchardgrass and red clover plus the general reaction of N-fertilizer application,we might suggest that they should be divided into three categeries in regard to the utilized condition of N-fertilizer applied on the mixture planting grassland as well as on the changing rhythms of N-fixation influence to the red clover sown on the grasslands:(1)After the lowest amount of N-fertilizer invested on the mixture-planting grassland,the land productivity only showed much lower,and meantimely,the red clover,quite the reverse,would provide much higher amount of N-fertilizer applied in variation;(2) whenever we invested the medium amount of N-fertizer on the mixture land, the land productivity would appear in medium phase,but the red clover supplied in its N-value which would seem to increase in a little amount;(3) while putting on N-fertilizer in higher amount,the red clover,on the contrary,would appear to lose some certain N value applied. Hence our trial would show that in consideration of the economical profit angle in this way so that we should suggest that so much the better to apply N-fertilizer in less amount,of course,that is to say,it is more suitable to apply N-fertilizer within the limits of 0 to 0.3 ton/ha,i.e., the amount applied is the best route for us to follow,anyway.