In South Florida, approximately 11,000 ha of rice is grown every summer on highly organic histosols. With no added fertilizer inputs of phosphorus (P) or nitrogen (N) as part of the cultivation program, growing flooded rice has the potential to reduce nutrient fluxes from soils to surface water and limit its losses to the water column. Changes in soil redox potential (E_h) will play an important role in the availability of P and nitrate (NO₃⁻) concentration within the groundwater, which ultimately drives the direction of diffusive fluxes across the soil–water interface. The objective of this study was to measure vertical E_h and groundwater concentrations of P and NO₃⁻ from commercial flooded rice fields and estimate diffusive fluxes across the soil–water interface. Results indicate that E_h was depth dependent, where deeper soils (30 cm deep) were slightly more anaerobic (mean − 162 mV) than shallow soils (15 cm deep) (mean − 144 mV). Groundwater P concentrations ranged between 0.38 and 1.09 mg L⁻¹ in deep soils (up to 60 cm) and 0.018–0.608 mg L⁻¹ in shallow soils (up to 40 cm). Groundwater NO₃⁻ concentrations ranged between 0.065 and 0.64 mg L⁻¹ in deep soils (up to 60 cm) and 0.055–0.499 mg L⁻¹ in shallow soils (up to 40 cm). Diffusive fluxes were mostly positive, which meant they flowed from shallow groundwater to the water column. Phosphorus fluxes were as high as 0.134 mg m⁻² d⁻¹ observed in 60-cm deep soils, whereas NO₃⁻ fluxes were as high as 0.12 mg m⁻² d⁻¹ observed in 40-cm shallow soils. Diffusive fluxes of P and NO₃⁻ from flooded rice fields were relatively lower compared to other hydrologic systems.

中文翻译：

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解释在组织溶胶上生长的商品稻的氧化还原电势（E h）和磷（P）和硝酸盐（NO 3-）的扩散通量

在南佛罗里达州，每年夏天在高度有机的组织溶胶下种植大约11,000公顷的稻米。作为耕种计划的一部分，在不添加磷（P）或氮（N）的肥料输入的情况下，种植泛滥的水稻有可能减少从土壤到地表水的养分通量，并限制其流向水柱的损失。在土壤的氧化还原电位的变化（Ë _ħ）将在P的可用性和硝酸盐（NO重要作用₃ ^- ）地下水内浓度，这最终驱动穿过土壤-水界面扩散通量的方向。本研究的目的是测量垂直È _ħ P和NO的和地下水浓度₃ ^-从商业淹没的稻田中获得，并估算穿过土壤-水界面的扩散通量。结果表明，E _h与深度有关，较深的土壤（30 cm深）的厌氧性（平均-162 mV）比浅土壤（15 cm深）（平均-144 mV）的厌氧性略高。在深层土壤（长达60厘米）中，地下水P的浓度范围为0.38至1.09 mg L ^-1；在浅层土壤（高达40 cm）中，浓度为0.018–0.608 mg L ^-1。在深层土壤（长达60厘米）中，地下水NO ₃ ^−的浓度范围在0.065至0.64 mg L ^-1之间，在0.055–0.499 mg L ^-1之间在浅土中（最大40厘米）。扩散通量大部分为正，这意味着它们从浅层地下水流到水柱。磷通量分别高达0.134毫克米^-2  d ^-1在60厘米深的土壤观察到的，而NO ₃ ^-通量分别高达0.12毫克米^-2  d ^-1在40-cm的浅的土壤观察。P和NO的扩散通量₃ ^-从淹没稻田被相对较低的相对于其他水文系统。