利用葉分析診斷柑桔營養狀態之研究

Abstract

1.使用柑桔園施肥試驗地之柑桔樹為材料進行葉分析做為柑桔營養診斷之基礎研究。施肥試驗於1958年1月在臺灣主要椪柑產地，員林一地點，新埔二地點開始進行，肥料處理分為無氮區，無磷區，無鉀區，三要素（對照）區，微量元素區等五處理。 2.於1959年3月，5月，7月，9月，11月分別採取各試驗地處理區之柑葉，分析其氮、磷、鉀含量探究施肥與時期對柑葉成分之影響。 3.柑葉 N. P. K含量隨季節之不同其變化甚大。五月各養分之濃度為最高，此為春天展開之新葉，以後各養分漸漸減低至翌年三月為最低，蓋三月所採者均為前年留下之老葉。 4.各試驗地柑葉之N含量，在無氮區平均為2.76%～3.03%而對照區為3.02%～3.21%。柑葉氮之臨界濃度推測為 3.0%附近。 5. P 含量在無磷區為0.131%～0.140%而對照區為0.138%～0.142%，其差異不大，但無氮區之P含量比對照區者顯著的增高，其差異達到統計的顯著標準。 6. K含量在無鉀區為0.86%～1.19%而對照區為0.98%～1.31%，類似P含量情形，無氮區之K含量亦有顯著的增高，所以柑桔樹在缺氮情形下似有增加吸收磷、鉀之傾向。NP含量在各柑桔園間之差異較少，但K含量其差異甚大，則平均K含量在照門為1.118%，大坪0.964%，員林1.272%。 7.檢討採葉位置即由枝頂第1,2,3,4葉及樣本採葉數20葉，40葉，80葉與葉成分之關係，其結果表示採葉位置及葉數對葉成分不大有影響。 1. Leaf analysis was conducted as a means of diagnosing nutritional status using Citrus Ponkan trees on the fertilizer experiment orchards as materials. The fertilizer experiments have been started since January, 1958 at one lacality in Yuanlin and two localities in Hsinpu, with five treatments layout, i. e. a) No N plot (PK), b) No P plot (NK), c) No K plot (NP), d) NPK plot (Check), e) Trace Elements plot (NPK+Mg, Mn, Zn). 2. Leaf samples were collected at each experimental plot in March, May, July, September and November 1959 respectively, then N, P, and K were analyzed in order to investigate the effect of fertilization and time of sampling on leaf compositions. 3. All these citrus trees had generally the highest leaf contonts of N, P and K in May which is at the early stage of foliation and these contents decreased gradually thereafter. In March next year, it became the lowest contents which is attributed to old age of leaves. 4. N contents in citrus leaves at each locality were 2.76%-3.03% on average in the no N plot, while there were 3.02%-3.21% in the check plot. The critical percent-tage of nitrogen in Citrus Ponkan leaves was considered at about 3.0%. 5. P contents in the no P plot were 0.131%-0.140% and there were 0.138%-0.142% in the check Plot. The differerence of P contents between these two plots was so small but it increased greatly at the no N plot. P contents in the no N plot was significantly higher than that in the check plot. 6. K contents in the no K plot were 0.86%-1.19% and there were 0.98%-1.31% in the check plot. K contents in the no N plot also showed apparently higher, so that nitrogen deficiency would be considered to promote the accumulation of P and K in citrus leaves. It was also found that the difference of K contents in leaves among those three orchards was quite large, but it was small in the case of N and P. 7. The position of leaves at citrus twigs and number of leaves sampled in this experiment was seemed to be little influennce on leaf compositions.