温州蜜柑叶片养分含量与产量关系的研究(初报)

本文阐述了温州蜜柑叶片中氮、磷、钾的周年规律性变化;认为花芽形态分化期(一月)叶片营养组分与产量有直接相关;提出了丰产温州蜜柑一月份叶片氮、磷、钾的含量指标。 1、温州蜜柑春梢叶片的营养元素含量,氮素以花芽生理分化期(九月)为最高,幼果期(五月)次之,花芽形态分化期(一月)最低。当年开花结果多时,也有出现九月叶片含氮量低于五月,或五月叶片含氮量低于一月的情况。春梢叶片中含磷、钾量均以四、五月为最高,随着叶今的增加而逐渐降低,至翌年一月～三月为最低,在结果多时,也有出现九月叶片含磷、钾量低于一月的情况。 2、我们认为,温州蜜柑叶片分析的采叶时期以花芽形态分化期(一月)摘取去年春梢营养枝叶片为宜。此时营养组分对当年的产量有明显的正相关。而五月、九月叶片营养含量常因开花结果量多少而波动。 3、温州蜜柑的丰产营养指标,据我们的研究结果,初步认为,花芽形态分化期(一月)叶片含氮量应为2.7％(占干物质重)以上,至少不低于2.5％水平;叶片含磷量应为0.16％以上;叶片含钾量应为1.0～1.5％。氮、钾比率以1.91—2.80为宜。花芽生理分化期(九月)叶片营养含量与翌年产量尚看不出其相关性,但叶片含磷量高有提高翌年座果率的趋势。

A PRELIMINARY REPORT ON THE RELATIONSHIP BETWEEN LEAF-ANALYSIS AND THE YIELDS OF SATSUMA MANDARIN

Investigations were made on the leaf N, P, K status in connection with the yields of Citrus unshiu Marc. in Sanming, Jian-ou and Liancheng districts, Fujian Province, from 1976 to 1977. Leaf-samples were collected from the 2nd-3rd nodes of the spring flush of the middle parts of the trees, growing in the red earth of hills, basins and mountains in January, May and September respectively. Preliminary analysis of the data gave the following remarks. 1. N-status of the leaves of satsuma mandarin showed the highest in September samples, the next in May (samples) and the least in January(samples). Leaves of the spring flush contained the highest P and K concentration in April-May sampling and the concentration decreased with the increase of leaf-age. 2. Therefore, January sampling from the vegetative terminals of the spring flush of the previous year should be recommended. The status of N, P and K correlated quite well with the yields, while samples of May and September varied with the quantity of flowering and fruiting. 3. The following leaf-analysis criteria for the maximum yields of satsuma mandarin are suggested: N—2.5—2.7%, P—0.16%, K—1.0-1.5%, N/K—1.91—2.80. No correlation was found between the leaf-status of N, P, K in September and the yield of the next year.