柑橘落花落果的营养元素含量及其脱落损耗

 以成年纽荷尔脐橙、兴津温州蜜柑和沙田柚为材料，研究落蕾、落花和脱落幼果中的养分含量及其脱落造成的损耗。结果表明，3 个品种的蕾和花营养元素含量为N 3.34% ~ 3.66%，P 0.26% ~0.31%，K 1.67% ~ 2.30%，Ca、Mg 和S 含量0.17% ~ 0.48%，Fe、Mn、Zn、Cu 和B 含量8.1 ~ 87.5 mg · kg^-1。除花的B 含量显著高于蕾外，花和蕾的多数营养元素含量相近，且品种间差异小。与蕾和花相比，幼果的N 和P 含量较少，N 和P 含量分别少21.8%和19.5%，但Fe 含量较多，其它营养元素含量变化不明显。纽荷尔脐橙、兴津温州蜜柑和沙田柚单株脱落的蕾、花和幼果干物质量合计分别为3 016.3 g、3 533.6 g和1 486.7 g，由此所造成的单株主要养分损耗为N 49.2 ~ 119.4 g、P 4.3 ~ 10.1 g、K 30.1 ~ 76.2 g、Mg 2.5 ~7.1 g、Zn 24.0 ~ 81.5 mg 和B 65.5 ~ 170.2 mg。兴津温州蜜柑和沙田柚均以落花的养分损耗最大，落蕾其次，落果最小；纽荷尔脐橙则是落花和落蕾的养分损耗相近且远高于落果。品种间以兴津温州蜜柑脱落的养分损耗最大，纽荷尔脐橙其次，沙田柚最小。因此，柑橘应控制过量开花，并在萌芽开花期及时补充养分。

Nutrient Element Content in Dropped Flowers and Young Fruits and Nutrient Losses Caused by Their Drops in Citrus

Nutrient element content in dropped flower buds，flowers and young fruits as well as thenutrient losses caused by their drops were studied in Newhall navel orange（Citrus sinensis L. Osb.‘Newhall’），Okitsu Wase satsuma（Citrus unshiu Marc.‘Okitsu Wase’）and Shatian pomelo（Citrusgrandis Osb.‘Shatian’）adult trees. Results showed that the nutrient element content in flower buds andflowers of the 3 varieties were N 3.34%–3.66%；P 0.26%–0.31%；K 1.67%–2.30%；Ca，Mg and Scontent were 0.17%–0.48%；Fe，Mn，Zn，Cu and B content were 8.1–87.5 mg · kg-1. B content wassignificantly higher in flowers than in flower buds，but other nutrient element content in flowers were closeto in flower buds. For the same organs，the content of each nutrient element was slightly different among the 3 varieties. Compared with flower buds and flowers，N and P content in young fruits greatlydecreased and Fe content increased obviously，while the average decreases by 21.8% N and 19.5% P weremeasured for the 3 varieties，but the changes of other nutrient element content were not remarkable. Thetotal dry weight of dropped flower buds，flowers and young fruits was 3 016.3 g per tree for Newhall navelorange，3 533.6 g per tree for Okitsu Wase satsuma，and 1 486.7 g per tree for Shatian pomelo，whichresulted in serious nutrient element losses of N 49.2–119.4 g，P 4.3–10.1 g，K 30.1–76.2 g，Mg 2.5–7.1g，Zn 24.0–81.5 mg and B 65.5–170.2 mg for per tree. The losses of nutrient element caused by flowerdrops > by flower bud drops > by young fruit drops for Okitsu Wase satsuma and Shatian pomelo，whilecaused by flower bud drops were close to by flower drops > by young fruit drops for Newhall navel orange.Okitsu Wase satsuma had the biggest losses of nutrient element caused by those drops，followed byNewhall navel orange and Shatian pomelo. Therefore，for citrus management practices，it’s important tocontrol excessive flowering，and to apply enough fertilizers during spring sprout and blossoms.