薄壳山核桃‘马汉’叶片主要矿质营养元素生育期动态变化特征

Dynamic Changes of Leaves' Main Mineral Elements in Pecan 'Mahan's Growth Period

以12年生薄壳山核桃‘马汉’为试验材料,采用凯氏定氮法、钼锑抗比色法和AAS法,测定不同生育期的结果枝成熟叶片中N、P、K、Ca、Mg、Fe、Cu、Zn、Mn等元素含量,分析叶片主要营养元素周年动态变化规律,为树体的营养诊断和合理施肥提供科学依据.结果显示：（1）叶中大量元素含量高低表现为N＞K＞Ca＞Mg＞P,微量元素含量高低表现为Mn＞Zn＞Fe＞Cu.（2）叶片对矿质营养元素的吸收具有明显季节性,其中开花授粉期对N、P、K、Cu的需求量较大,坐果期和果实膨大期对N、P、K的需求量较大,果实发育期对K、Zn、Mn的吸收有持续增加的趋势.（3）随时间推移叶片中各营养元素周年动态变化出现规律性波动,且大量元素波动较小,微量元素波动较大.研究表明,薄壳山核桃叶营养元素相对稳定时期（7月27日～8月13日）拟应推荐作为薄壳山核桃叶营养诊断的适宜时期,同时应以施用N、P、K肥为主,Ca、Mg为辅助肥料,在开花授粉期和坐果期适量追肥,并在采收秋果前深施有机肥作基肥.

In order to elucidate the dynamic changes of the mineral elements in leaves of 12-＊year old mature pecan trees＇ bearing branches and provide a scientific basis for tree nutrition diagnosis and reasonable fertilization in future,we tested nine elements（N,P,K,Ca,Mg,Fe,Cu,Zn,Mn） by the Kjeldahl method,Mo-Sb colorimetry and atomic absorption.The results showed that：（1）The contents of different macro-element in mature leaves of pecan ‘Mahan’ were put in the following order：N＞K＞Ca＞Mg＞P,while the contents of different micro element were put in the following order：Mn＞Zn＞Fe＞Cu.（2）The mature leaves’ absorption of mineral elements had obvious seasonal features：N,P,K and Cu were needed greater during the pollination flowering period,as well as N,P,K were needed more during the flushing period and fruit expanding period;the absorption of K,Zn,Mn had a tendency to continue to increase during the fruit growth period.（3）The contents of mineral elements in leaves were fluctuated according to time lapse.For macro-element,the fluctuation was small,but for micro element,the fluctuation was noticeable large.The conclusion is that the appropriate period for analyzing the standards of nutrition diagnosis in pecan leaves is from July 27th to August 13th.It is recommended that N,P,K and Ca,Mg,respectively as primary and secondary base fertilizer should be added in the pollination flowering period and the flushing period,while organic fertilizer should be deep fertilized before the harvest of autumn fruit.