杉木苗期氮磷钾营养及诊断的研究

采用最优化设计安排了氮磷钾三因素五水平(分别为氮:0.0,0.5,1.0,1.5,2.0;磷:0.0,0.3,0.6,0.9,1.2;钾:0.0,0.4,0.8,1.2,1.6g/桶)的肥料试验,供试土壤有效氮、磷缺乏。研究结果表明,氮、磷配合适宜的N_3P_3K_1,N_2P_4K_4及N_1P_3K_3氮磷钾肥利用率较高或最高,氮过多磷不足则氮肥利用率低,导致氮肥浪费并且抑制杉苗生长和生理活性;磷肥可明显促进杉苗对氮肥的吸收。多数生长、生理指标与杉苗针叶全氦、全磷、全钾之间存在显著的二次抛物线关系,据此进行营养诊断可得到较客观的结果。采用综合诊断施肥法(DRIS)可诊断杉木各苗期的营养平衡状况及定量地判断需肥程度和顺序,合理制订各苗期针叶养分的适宜比值。这两种方法相结合得到了一个较完整的杉苗营养诊断指标体系。

STUDY ON THE NITROGEN, PHOSPHORUS,POTASSIUM NUTRITION AND THEIR DIAGNOSIS IN CHINESE FIR SEEDLINGS

An optimized design was adopted to arrange the pot fertilizer experiment including three factors N.P.K with five levels i. e N:0.0, 0.5, 1.0, 1.5, 2.00; P:0.0, 0.3, 0.6, 0.9, 1.2; K:0.0, 0.4, 0.8, 1.2, 1.6(g/pot). The soil for the trial was lack of availadle N. P. The results of the research showed that the treatments N3P3K1, N2P4K4and N1P3K3With proper combination between N and P, had higher or highest availability of N. P. K. The availability of N under the condition of high N and low P was low, which resulted in the waste of N and in the depression of the growth and some physiological activities of Chinese fir seedlings. Ppro-moted the adsorption of N remarkably. There were significant correlations of one variable binomial equation between most of the items of growth and physiology and the total N, total p, total K in the leave of Chinese fir seedlings. The models were used for the nutritional diagnosis to obstain more pratical results. DRIS ( Diagnosis Recomme ndation and Integrated System ) was adopted to diagnose the status of the balance of the various elements and to determine the sequences of fertilizing and the proper ratios of the elements in various periods of growth precisely. Therefore, the more integrated diagnosis indices of Chinese fir seedlings were obtained by combining the two methods.