ABSTRACT The soils of the Everglades Agricultural Area (EAA) are mainly organic soils (Histosols), and their artificial drainage promoted aeration and resulted in soil subsidence. Sugarcane (Saccharum spp.) nitrogen (N) requirement has been fulfilled historically by organic matter mineralization, so very shallow soils could be limiting N availability for the crop. The objectives of this study were to measure sugarcane leaf N concentration and levels of available N across EAA organic soils with variable soil depth and then determine if there are relationships among soil depth, soil N concentration, and sugarcane leaf N concentration in Florida Histosols. A total of 60 plots were established in 30 commercial sugarcane fields in the EAA with soil depth varying from 15 to 145 cm over limestone bedrock. In each location, soil depth, soil, and leaf nutrient concentrations, and leaf chlorophyll measurements were determined during the grand growth period (June 1 – October 15) of the crop. There were no significant correlations between soil depth and either leaf N concentration or leaf chlorophyll measurements. There were positive correlations between soil water and soil NH4 +-N concentration and between soil NO3 –N concentration and leaf N concentration. Our results determined that mineralization is still providing adequate N supply for sugarcane.

中文翻译：

---

浅佛罗里达组织溶胶的氮评估

摘要 大沼泽地农业区（EAA）的土壤主要是有机土壤（Histosols），其人工排水促进通气并导致土壤沉降。甘蔗 (Saccharum spp.) 对氮 (N) 的需求历来是通过有机质矿化来满足的，因此非常浅的土壤可能会限制作物对氮的可用性。本研究的目的是测量不同土壤深度的 EAA 有机土壤中甘蔗叶 N 浓度和有效 N 水平，然后确定佛罗里达 Histosols 中土壤深度、土壤 N 浓度和甘蔗叶 N 浓度之间是否存在关系。在 EAA 的 30 个商业甘蔗田中建立了总共 60 个地块，石灰岩基岩上的土壤深度从 15 到 145 厘米不等。在每个位置，土壤深度、土壤、和叶片养分浓度以及叶片叶绿素测量值是在作物的大生长期（6 月 1 日至 10 月 15 日）确定的。土壤深度与叶片 N 浓度或叶片叶绿素测量值之间没有显着相关性。土壤水分与土壤NH4+-N浓度、土壤NO3-N浓度与叶片N浓度呈正相关。我们的结果确定矿化作用仍然为甘蔗提供充足的氮供应。土壤水分与土壤NH4+-N浓度、土壤NO3-N浓度与叶片N浓度呈正相关。我们的结果确定矿化作用仍然为甘蔗提供充足的氮供应。土壤水分与土壤NH4+-N浓度、土壤NO3-N浓度与叶片N浓度呈正相关。我们的结果确定矿化作用仍然为甘蔗提供充足的氮供应。