施用氮磷钾对密植梨枣生长与叶片养分季节动态的影响

Effects of fertilization on growth and seasonal dynamic of leaf nutrients of close planting pear-jujube trees

以山地梨枣(Zizyphus jujuba Mill.cv.Lizao)为试验材料,采用野外试验与室内分析,研究了黄土丘陵区山地滴灌下施用氮磷钾对矮化密植梨枣生长,产量及品质的影响以及施肥对梨枣叶片8种营养元素(N、P、K、Ca、Mg、Fe、Mn、Zn)季节动态变化规律。结果表明:施氮肥可促进前期枣树新枝生长和枣果膨大;施磷肥可提高产量,达到33210 kg/hm2;施钾肥可明显提高枣果品质。不同生育期梨枣叶片养分含量变化也具有一定的规律性。开花坐果期(5月上旬至7月上旬),叶片N、P、K含量处较高水平,Mg、Fe、Mn、Zn含量处于较低水平。果实膨大期(7月中下旬到8月下旬),叶片N、P有一个相对稳定的含量,K快速下降,而Fe、Mn、Zn含量上升。果实成熟期(9月初到10月初),叶片N、P、K含量下降,Mg、Fe、Mn、Zn则是缓慢上升并趋于稳定。叶片N、P、K、Mn含量之间呈正相关,Ca、Mg、Fe、Zn含量之间也呈正相关关系,叶片N、P、K之间达极显著正相关关系,而N、P、K与Ca、Mg、Fe、Zn含量之间呈负相关关系。

To investigate the influence of different fertilization on jujube nutrients, field experiments were conducted in loess hilly-gully mountains, and pear-jujube （Zizyphus jujuba Mill. cv. Lizao） was used as experimental materi- als. The plant development, productivity and fruit quality of pear-jujube in different fertilizer application conditions were studied, and the seasonal dynamic changes of eight kinds of nutrition elements （ N, P, K, Ca, Mn, Zn and Fe） of pear-jujube leaves were also examined. The results show that N fertilizer can increase the growth of the new bran- ches and the jujube enlargement. P fertilizer can improve fruit yield to 33210 kg/ha; K fertilizer can improve fruit quality. Therefore, P and K fertilizer cooperating application can increase both yield and quality of the pear-jujube. The results show that the contents of N, P and K of the pear-jujube at the blossom and fruit-set period （from early May to early July） are in higher levels, compared with Mg, Fe, Mn and Zn. Besides, the contents of N and P in leaves are relatively stable at the fruit enlargement period （from middle July to late August） ; at the same time, K is declined drastically, while trace elements （Fe, Mn and Zn） llave rising trends. At the fruit maturation stage （from early September to early October）, the contents of N, P and K in leaves are decreased, whereas Fe, Mn and Zn are increased slowly or remained basically unchanged. So we conclude that there are positive correlations between N, P, K and Mn and between Ca, Mg, Fe and Zn in leaves of jujube in the growth period. Furthermore the contents of N,P and K have significantly positive correlations, however, the content of N, P and K correlate negatively to Ca, Mg, Fe and Zn in jujube leaves.