氮磷钾肥料施用对核桃蛋白质和粗脂肪含量的影响

Effects of nitrogen,phosphorus and potassium fertilizer application on protein and crude fat content of walnut

核桃生产中盲目施肥和品质低劣的问题普遍存在。为了明确不同肥料施用对核桃品质的影响,确定实现优质核桃生产的适宜肥料用量,以6年生‘香玲’为供试植物,在氮(N 0、0.25、0.50、0.75、1.25 kg·株^(-1))、磷(P2O50、0.10、0.20、0.40、0.80 kg·株^(-1))、钾(K_(2)O 0、0.15、0.30、0.60、1.20 kg·株^(-1))各设置5个施肥水平的情况下,研究了氮肥、磷肥、钾肥不同用量对核桃果仁蛋白质和粗脂肪含量2个主要品质指标的影响。结果表明:氮肥、磷肥施用对果仁蛋白质含量影响不显著;钾肥施用显著影响果仁蛋白质含量,随钾肥用量的增加,果仁蛋白质含量呈先升后降的变化趋势,其数学关系符合一元二次函数方程y=-5.2872x2+4.2009x+19.27(0.001<P<0.01)。由此函数方程计算可知,果仁蛋白质含量最大值为20.1%,获得最大蛋白质含量的钾肥用量为K_(2)O 0.40 kg·株^(-1)。氮肥、钾肥施用对果仁粗脂肪含量影响显著,氮肥用量和钾肥用量与果仁粗脂肪含量的数学关系均符合直线加平台数学模型(P<0.001;0.001<P<0.01),根据直线加平台模型的模拟结果,氮肥、钾肥用量为N 0.68 kg·株^(-1)和K_(2)O 1.24 kg·株^(-1)时,核桃果仁的粗脂肪含量达到最高,分别为61.1%和65.1%;磷肥施用对果仁粗脂肪含量的影响未达显著水平。根据不同施肥处理的果仁蛋白质和粗脂肪含量,采用隶属函数法对核桃品质进行综合评价,氮肥、磷肥和钾肥用量分别为N 1.25 kg·株^(-1)、P2O50.20 kg·株^(-1)和K_(2)O 0.60 kg·株^(-1)时,平均隶属函数值最大,核桃果仁的综合品质最好。综上,不同肥料施用对核桃各单一品质指标和综合品质的影响不同,生产中应根据生产目标进行合理施肥量的推荐。

Blind fertilization and poor quality are common problems in walnut production.In order to clarify the effects of different fertilizer application on the quality of walnut and determine the appropriate amount of fertilizer to achieve high-quality walnut production,6-year-old‘Xiangling’was used as the test plant,the effects of nitrogen(N 0,0.25,0.50,0.75,1.25 kg·plant^(-1)),phosphorus(P2O50,0.10,0.20,0.40,0.80 kg·plant^(-1))and potassium(K_(2)O 0,0.15,0.30,0.60,1.20 kg·plant^(-1))on two main quality indexes of walnut kernel,the protein and crude fat content,were studied under five fertilization levels.The results showed that nitrogen fertilizer and phosphorus fertilizer had no significant effects on the protein content of walnut kernel.The application of potassium fertilizer significantly affected the protein content of walnut kernel.With the increase of potassium fertilizer application rate,the protein content of walnut kernel increased first and then decreased,and the mathematical relationship conformed to the quadratic function equation y=-5.2872x2+4.2009x+19.27(0.001<P<0.01).The function equation calculation showed that the maximum protein content of walnut kernel was 20.1%,and the corresponding potassium application was K_(2)O 0.40 kg·plant^(-1).The application of nitrogen fertilizer and potassium fertilizer had a significant effect on the crude fat content of walnut kernel.The mathematical relationship between the amount of nitrogen fertilizer,potassium fertilizer and the crude fat content of walnut kernel conformed to the linear plus platform mathematical model(P<0.001;0.001<P<0.01).According to the simulation results,when the amount of nitrogen fertilizer and potassium fertilizer were N 0.68 kg·plant^(-1)and K_(2)O 1.24 kg·plant^(-1),the crude fat content of the walnut kernel reached the highest value,which was 61.1%and 65.1%respectively.The effect of phosphate fertilizer application on crude fat content in walnut kernels was not significant.According to the protein and crude fat content of walnut kernel under different fertilization treatments,the membership function method was used to comprehensively evaluate walnut quality in this study.When nitrogen fertilizer,phosphate fertilizer and potassium fertilizer application rate were at N 1.25 kg·plant^(-1),P_(2)O_(5) 0.20 kg·plant^(-1)and K_(2)O 0.60 kg·plant^(-1)respectively,the average membership function values were the largest,and the comprehensive quality of walnut kernels were the best.In summary,nitrogen,phosphate and potassium fertilizer applications had different effects on single quality index and the comprehensive quality of walnut kernels,so a reasonable amount of fertilizer should be recommended according to the production target.