荔枝年生长周期内N、P、K营养动态规律与施肥管理体系

通过3年大田试验探索荔枝年生长周期内N、P、K营养规律,验证由高氮、高磷钾、高钾复合肥组成的荔枝平衡施肥管理措施的适用性。结果表明,荔枝年生长周期内,收获期N、P、K营养水平降至最低,随后因施肥而迅速恢复,在秋梢老熟到花芽分化期达年周期内最大值,此后随着开花结果N、P、K营养水平逐渐下降,至新的收获期又降至最低水平。秋梢和果枝的N、P、K水平因生长期的不同而明显变化,然而肥料用量(3～5kg/树)和N∶P∶K比例对树体N、P、K水平的影响较小。每个生育期结果母枝的N、P、K含量依次为N>K>P。收获期到开花前是树体营养恢复阶段,开花到果实生长发育期是消耗体内贮藏态N、P、K的过程。在荔枝年生长周期内,分别在收获期、秋梢老熟期和坐果期施用高氮复合肥、高磷钾复合肥和高钾复合肥能保障年周期内荔枝树体N、P、K营养水平处于最佳状态。

N,P,K Nutrition Dynamics of Litchi During the Annual Growth Cycle

Three-year field trials were carried out for studying the N, P and K nutrition state of Heiye litchi cultivar and their dynamic changes in annual growth cycle in order to design a balanced fertilization stratagem. Results showed that N,P,K level reached minimum at harvest in annual cycle. The nutrition level recovered to the maximum at autumn shoot maturation stage (ASMS), then the N,P,K level dropped to the lowest once again from blossom to new harvest stage. The N,P,K nutrition level in autumn and fruiting shoots fluctuated with growth season and not affected by dosage within 3 to 5 kg per tree and N,P,K ratio of compounds. N,P,K in leaves was in order of N > K > P for each growth stage. The time from harvest to ASMS was duration of N,P,K recovery. However, the period from flowering to new harvest was the period to consume N,P,K stored in leaves. Therefore, fertilizing litchi with high N, high P and K and high K compounds at harvest, autumn shoots maturation and fruit setting stage respectively were capable to keep N,P,K nutrition at optimum in leaves of fruiting shoots within annual growth cycle.