Reduction Of Phosphorus Inputs Research Articles

The Potential of Microgranular Fertilizers to Reduce Nutrient Surpluses When Growing Maize (Zea mays) in Regions with High Livestock Farming Intensity.

This contribution provides the first agroeconomic account of the application of a mineral microgranular fertilizer and an organomineral microgranular fertilizer directly beneath the corn in comparison to a common mineral band fertilizer in temperate climate regions. The focus of the study is on the reduction in phosphorus inputs while maintaining the yield of maize plants (Zea mays). The study used a three-year field trial to tabulate dry matter yields using the two phosphorus-reduced microgranular fertilizers, as well as a standard diammonium phosphate (DAP) fertilization method. The application of the organomineral microgranular fertilizer resulted in dry matter yields that were 15% higher (2.8 Mg per hectare) than the DAP variant, while higher yields using the mineral microgranular fertilizer only occurred in a single year. The higher yield of the organomineral microgranular fertilizer and the lower phosphorus amounts as a result of using that product resulted in a moderate phosphorus excess of 2.7 kg P ha-1, while DAP fertilization resulted in a surplus of 25.5 kg per hectare. The phosphorus balance on the plots fertilized with the mineral microgranular fertilizer followed a pattern similar to that of the organomineral microgranular fertilizer. We conclude that both microgranular fertilizers, applied directly beneath the corn, provide an adequate alternative to widespread DAP fertilization as a fertilizer band in maize cultivation on fertile soils.

Two mathematical approaches to study the phosphorus eutrophication of a wetland in Puerto Rico

Introduction: Laguna Cartagena (LC), a wetland in Lajas, Puerto Rico, has been negatively impacted by nutrients, mainly phosphorus run-off from agricultural activities until the end of sugar cane cultivation in the late 1900s. This led to P concentration remain high at hypereutrophic state that was irremediable even after a 5-fold reduction in source water nutrient concentration.
 Objective: The main goal of this research paper is to apply two different mathematical approaches to assess the eutrophication level of a wetland in Puerto Rico.
 Method: Grey Cluster Method (GCM) was used to classify LC’s eutrophic state by applying the International and Chinese trophic standards and two parameters, total phosphorous (TP) and total nitrogen (TN). Mean TP and TN from LC consolidated bottom substrate and flocculence samples were used to classify LC. To address whether LC can recover, soluble reactive phosphorus (SRP) and TP from LC inlet, outlet and center water samples were used to model (differential equation) the input and loss of phosphorus in LC and determine whether an equilibrium point exists. GCM analysis classified LC as a eutrophic wetland using the International standard and hypereutrophic using the Chinese standard.
 Results: Trophic state classification did not vary with use of consolidated bottom substrate versus flocculence samples. The differential equation model showed that SRP and TP levels within LC were higher than levels of SRP and TP entering LC, which could be caused by a nutrient recycling process within LC that may predict failure of remediation efforts. An equilibrium point was found at the eutrophic level, which means that even if there is a reduction in phosphorus input, there will not be a change in LC’s eutrophic state.
 Conclusions: Chinese trophic standard indicated LC was in a hypertrophic state. Similar results were found using the international standard. The differential equation model showed that LC is irreversible.

Major agricultural changes required to mitigate phosphorus losses under climate change

Phosphorus losses from land to water will be impacted by climate change and land management for food production, with detrimental impacts on aquatic ecosystems. Here we use a unique combination of methods to evaluate the impact of projected climate change on future phosphorus transfers, and to assess what scale of agricultural change would be needed to mitigate these transfers. We combine novel high-frequency phosphorus flux data from three representative catchments across the UK, a new high-spatial resolution climate model, uncertainty estimates from an ensemble of future climate simulations, two phosphorus transfer models of contrasting complexity and a simplified representation of the potential intensification of agriculture based on expert elicitation from land managers. We show that the effect of climate change on average winter phosphorus loads (predicted increase up to 30% by 2050s) will be limited only by large-scale agricultural changes (e.g., 20–80% reduction in phosphorus inputs).

The Impact of Nitrogen and Phosphorus Dynamics on the Kinneret Phytoplankton: I: Cyanophytes-Peridinium Alternate

During 1970-2001, several ecological changes were documented in the Lake Kinneret Ecosystem: Decline of total Nitrogen (TN) and increase of total Phosphorus (TP) loads with a corresponding decline of TN/TP ratio. The phytoplankton assemblages indicated consequence Increase of Cyanobacteria accompanied by elevation of the biomass of Chlorophyta and Diatoms. The Kinneret ecosystem functioning represented two superimposed events: the decline of TN enhanced Cyanobacteria and elevation of TP that was reflected by an increase of Chloropytes and Diatoms. Removal of Nitrogen was achieved but P load remained high enough to enhance Chlorophyta and Diatoms. Consequently, a top priority of future management perspective should be reduction of Phosphorus inputs.

The response of the rotifer community in Loch Leven, UK, to changes associated with a 60% reduction in phosphorus inputs from the catchment

Lakes across the world are suffering from anthropogenically induced nutrient enrichment problems and many attempts are being made to improve their water quality and ecosystem function. Most metrics that are being used to monitor recovery are based on relationships that have been established across a range of lakes. These may not respond quickly to in‐lake changes in water quality when nutrient management strategies are put in place. This paper uses data routinely collected from Loch Leven, UK, to examine the immediate and longer‐term responses of the rotifer community to a 60% reduction in phosphorus input from the catchment in the early 1990s. We conclude that changes in rotifer abundance and relative species composition are sensitive indicators of lake‐specific changes in water quality, responding more quickly than more widely used metrics, such as total phosphorus and chlorophyll a concentrations. However, like all indicators of change, such indices must be used with care in situations where rotifer populations are subject to multiple stressors.

The restoration of Lake Apopka in relation to alternative stable states

Lake Apopka (Florida, USA) changed in 1947 from being a clear, macrophyte-dominated lake, used primarily for fishing, into a turbid algal lake with a poor fishery. The lake has resisted various efforts to reverse the change and restore the previous state. The restoration approach emphasizes the reduction in phosphorus inputs to reduce algal blooms and clear the water. We examined the question of whether a deep-lake approach with nutrient reductions is going to work on this large (area 124 km2) and shallow (mean depth 1.7 m) lake, or if techniques such as drawdowns or wind barriers developed for shallow lakes using the theory of alternative stable states are more applicable.

Lake restoration by biomanipulation—a personal view

Restoration of over-fertilized, algae-laden lakes and reservoirs has generally been based on removal or reduction of phosphorus inputs and concentrations. However, this approach frequently is not feasible. An alternative is biomanipulation, in which the biota of the water body, particularly the fish population, is manipulated so as to reduce predation on small herbivorous zooplankters. This results in increases in body size of the zooplankters with consequent great increases in grazing rates on the algae. The process, though controversial, has worked in many lakes and offers promise to many more.Key words: biomanipulation, trophic cascade, lake restoration.

Lake restoration by reducing external phosphorus loading: the influence of sediment phosphorus release

SUMMARY. 1. This review considers the factors which determine the recovery of eutrophic lakes following a reduction in the external phosphorus loading.2 The mean phosphorus content of a lake should decrease roughly in proportion to the reduction in phosphorus input. Where the lake phosphorus concentration does not decrease as predicted, then the release of phosphorus from the sediment is implicated.3. The current understanding of the processes by which sediment phosphorus is mobilized and transported into the photic zone is described. The extent to which phosphorus release can maintain lake phosphorus concentrations following the reduction in external loading is influenced by: lake morphometry, flushing rate, sediment type, trophic state and history of enrichment.4. A reduction in the phytoplankton biomass of a lake is dependent upon the size of the decrease in lake phosphorus concentration and the degree to which phosphorus limits primary production. The importance of phosphorus in limiting phytoplankton production tends to decrease with increasing lake trophic status.5. Improvements in the condition of highly eutrophic lakes require very large reductions in external phosphorus loading, whereas in mildly enriched lakes moderate changes in the supply of phosphorus have noticeable effects on phytoplankton biomass.

The Problem of Phosphorus in France – Its Presence in Natural Waters and Biological Phosphorus Removal

The problem of nutrient inputs to surface waters is reviewed. These inputs lead to eutrophication and an undesirable decrease in water quality. The origin and effects of eutrophication, and the principles of its control are described. The preferred method of control is through the reduction of phosphorus inputs. The origins of phosphorus inputs and methods of limiting these are considered, in particular through physico-chemical and biological treatment processes in sewage treatment plants. It is concluded that efficient control of eutrophication through reduction of phosphorus inputs is possible.