大田条件下山核桃林地土壤和叶片养分变化规律

Seasonal changes of soil and leaf nutrient levels in a Carya cathayensis orchard

对石灰岩母岩土壤山核桃Carya cathayensis林地开展定位研究。通过对土壤养分及山核桃叶片氮、磷、钾质量分数变化的动态分析测定,研究山核桃林地土壤养分水平现状及季节性变化,探讨山核桃叶片养分的变化规律及与土壤养分水平及施肥的关系。结果表明:与10a前相比较,山核桃林地土壤氮、磷、钾养分积累明显,但是土壤酸化严重,土壤pH4.5。对山核桃叶片养分动态分析显示,随着山核桃的生长、开花、结果和果实膨大直至成熟,山核桃叶片氮、磷、钾质量分数水平呈现下降的趋势,叶片氮、磷、钾质量分数分别变幅在10.6～15.4,0.9～2.2和5.2～11.8g·kg-1。叶片养分水平与果实之间养分供应源库关系明显。综合分析表明,目前山核桃林地氮、磷、钾肥料施用过多,应根据山核桃对养分的需求特点,控制大量元素肥料的施用量,加强微量元素肥料的施用,从而实现稳产高产并提高品质。

To understand current soil nutrient conditions for growth, nutrient status, and relationships between soil nutrients and growth of Carya cathayensis in limestone soils, soil samples and corresponding leaf and nut samples were collected from a C. ca^hayensis plantation in Daoshi Town of Zhejiang Province, Chi- na. Also, seasonal changes of soil and plant leaf nutrients were analyzed. Results showed that leaf N, P, and K decreased（P〈0.05） from flowering to nut maturity regardless of fertilizer topdressings. Thus, fruit is a strong sink for N, P and K nutrients. Soil organic matter and N, P, and K accumulated greatly compared to 10 years before （data from the reference）. Soil acidification was serious with soil pH decreasing to 4.5. Because of fertilization, soils generally maintained high levels of available N, P, and K, so responses of N, P, and K in tree leaves were not apparent. Also, even though fertilization provided sufficient nutrients, overdoses of NPK could cause detrimental increases in soil acidity and environmental pollution. Therefore leaf N, P and K recommendations for optimal growth and non-polluting, sustained production are necessary. [Ch, 3 tab. 18 ref. ]