不同氮素用量对甜荞麦干物质和养分积累及分配的影响

为了掌握甜荞麦适宜施氮量,研究不同供氮水平对甜荞麦干物质和养分积累及分配影响的规律。采用田间小区试验的方法,设置5个氮素水平N_0、N_1、N_2、N_3和N_4(0,30,60,90,120 kg/hm~2),研究了甜荞麦不同器官干物质和养分积累量及分配比例的变化。结果表明,甜荞麦干物质积累总量随着施氮量的增加呈先增后降的趋势,N_2处理干物质积累总量最大,但N_3处理籽粒中干物质积累量和分配比例最大。荞麦籽粒氮、磷和钾含量随着氮肥用量的增加先增后降,N_3处理籽粒中氮、磷、钾养分含量最大;增加施氮量可提高氮、磷和钾在籽粒中的分配比例,但会降低它们在茎和叶中的分配比例。甜荞麦生产100 kg籽粒平均需吸收N 7.09 kg、P_2O_5 4.15 kg、K_2O 8.74 kg,养分比例为1∶0.59∶1.24,养分生产效率随着氮肥用量的增加先增后降,N_3处理的氮磷钾养分生产效率均达最高。随着氮肥用量的增加,氮磷干物质生产效率先增后降而后又上升,钾的干物质生产效率逐渐上升,N_4处理的氮磷钾干物质生产效率均达最高。综合考虑干物质和养分积累及分配因素,施氮量90 kg/hm~2为甜荞麦适宜氮肥用量。

Effects of Nitrogen Fertilizer Rate on Dry Matter and Nutrient Accumulation and Distribution of Buckwheat

In order to explore the suitable nitrogen application,the influence of dry matter and nutrient element accumulation and distribution under different N application levels on buckwheat was studied.Field experiment was conducted under different N application rates N0,N1,N2,N3 and N4(0,30,60,90,120 kg/ha).The results showed that buckwheat dry matter first increased and then dropped with the increment of nitrogen application rate.When the nitrogen application rate was N2,the buckwheat dry matter reached the highest.But when the nitrogen application rate was N3 ,the seeds dry matter and distribution rate reached the highest.The results also showed that seeds nitrogen,phosphorus and potassium contents first increased and then dropped with the increment of nitrogen application rate.When the nitrogen application rate was N3 ,the seeds nitrogen,phosphorus and potassium contents reached the highest.The seeds nitrogen,phosphorus and potassium distribution rate increased with the increment of nitrogen application rate,but it decreased in stems and leaf.The amounts of nutrients which needed for the formation of 100 kg seeds of buckwheat were N 7.09 kg,P2O5 4.15 kg,K2O 8.74 kg and the rate was 1.00∶0.59∶1.24.The production efficiency of N,P2O5,K2O first increased and then dropped with the increment of nitrogen application rate.When the nitrogen application rate was N3 ,the production efficiency of N,P2O5,K2O reached the highest.With the increase of the amount of nitrogen fertilizer, the dry matter production efficiency of nitrogen and phosphorus first increased, then decreased, and then increased.The dry matter production efficiency of potassium gradually increased, and the production efficiency of N4, nitrogen, phosphorus and potassium dry matter reached the highest level.Considering the buckwheat dry matter and nutrient element under the experimental conditions,N application rate of 90 kg/ha identified to be the suitable amount.