Fertilisers and phosphorus loss from productive grazing systems

Soil Research ◽  
1999 ◽  
Vol 37 (3) ◽  
pp. 403 ◽  
Author(s):  
David M. Nash ◽  
David J. Halliwell
Keyword(s):  
Management Strategies ◽  
Phosphorus Uptake ◽  
Macropore Flow ◽  
Phosphorus Species ◽  
Phosphorus Loss ◽  
Nutrient Sources ◽  
Matrix Flow ◽  
Grazing Systems ◽  
Phosphorus Losses ◽  
Species Being

This paper reviews phosphorus loss from productive high rainfall grazing systems. In particular it describes the processes occurring when phosphatic fertilisers are added to soil, the different pathways through which fertiliser and other nutrient sources may contribute to phosphorus losses, and an evaluation of the management strategies aimed at minimising phosphorus loss. It is now generally accepted that soil is not an endless sink for phosphorus uptake and that at the landscape scale the highest concentrations of phosphorus loss occur in surface runoff, followed by macropore flow and vertical matrix flow. However, loads of phosphorus lost through these pathways are unknown. The development of an understanding of the transport mechanisms and phosphorus species being transported is fundamental to developing management strategies that are effective in decreasing phosphorus losses from grazing systems.

Periphytic microbial response to environmental phosphate bioavailability – relevance to P management in paddy fields

2021 ◽  
Author(s):  
Jianchao Zhang ◽  
Jing Su ◽  
Chao Ma ◽  
Xiangyu Hu ◽  
Henry H Teng
Keyword(s):  
Management Strategies ◽  
Phosphorus Uptake ◽  
Paddy Fields ◽  
P Availability ◽  
Biochemical Processes ◽  
Extracellular Metabolite ◽  
Microbial Response ◽  
P Utilization ◽  
Water Ecosystems ◽  
And Storage

Periphyton occurs widely in shallow-water ecosystems such as paddy fields and plays critical parts in regulating local phosphorus cycling. As such, understanding the mechanisms of the biofilm’s response to environmental P variability may lead to better perceptions of P utilization and retention in rice farms. Present study aims at exploring the biological and biochemical processes underlying periphyton’s P buffering capability through examining changes in community structure, phosphorus uptake and storage, and molecular makeup of exometabolome at different levels of P availability. Under stressed (both excessive and scarce) phosphorus conditions, we found increased populations of the bacterial genus capable of transforming orthophosphate to polyphosphate, as well as mixotrophic algae who can survive through phagotrophy. These results were corroborated by observed polyphosphate buildup under low and high P treatment. Exometabolomic analyses further revealed that periphytic organisms may substitute S-containing lipids for phospholipids, use siderophores to dissolve iron (hydr)oxides to scavenge adsorbed P, and synthesize auxins to resist phosphorus starvation. These findings not only shed light on the mechanistic insights responsible for driving the periphytic P buffer but attest to the ecological roles of periphyton in aiding plants such as rice to overcome P limitations in natural environment. Importance The ability of periphyton to buffer environmental P in shallow aquatic ecosystems may be a natural lesson on P utilization and retention in paddy fields. This work revealed the routes and tools through which periphytic organisms adapt to and regulate ambient P fluctuation. The mechanistic understanding further implicates that the biofilm may serve rice plants to alleviate P stress. Additional results from extracellular metabolite analyses suggest the dissolved periphytic exometabolome can be a valuable nutrient source for soil microbes and plants to reduce biosynthetic costs. These discoveries have the potential to improve our understanding of biogeochemical cycling of phosphorus in general and to refine P management strategies for rice farm in particular.

Spatial variability in pH and key soil nutrients: is this an opportunity to increase fertiliser and lime-use efficiency in grazing systems?

2014 ◽  
Vol 65 (8) ◽  
pp. 817 ◽  
Author(s):  
Mark Trotter ◽  
Chris Guppy ◽  
Rebecca Haling ◽  
Tieneke Trotter ◽  
Clare Edwards ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Nutrient Use Efficiency ◽  
Management Strategies ◽  
Critical Values ◽  
Limiting Factors ◽  
South Wales ◽  
Nutrient Use ◽  
Grazing Systems ◽  
Use Efficiency ◽  
Fertiliser Use

Nutrient-use efficiency is a key issue for grazing systems in Australia. Spatial variability in soil pH and nutrients at the sub-paddock scale may affect the efficiency of utilisation of, and provide an opportunity for, site-specific management (SSM) of fertiliser and soil ameliorants. However, there has been little research exploring the potential for SSM in grazing systems. This study examines the spatial variability of soil test pH, phosphorus (P), potassium (K) and sulfur (S) in two typical pasture fields (a native and an improved) on the Northern Tablelands of New South Wales and evaluates the potential for SSM based on a comparison with critical values. In both fields, the overall paddock mean from a grid survey containing >80 samples for pH, P, K and S (0–10 cm) exceeded the critical values, suggesting that the addition of fertiliser or lime was not required. However, considerable sub-paddock-scale variability was observed, with CV ranging from 35% to 66% for the key nutrients (P, K and S). The Sprengel–Liebig Law of the Minimum was applied to evaluate the proportion of each field constrained by one or more soil characteristics. Up to 55% of the improved paddock and 78% of the native pasture was potentially responsive to amendments. The results of this study suggest that SSM of fertilisers and ameliorants could provide substantial improvements in productivity and possibly reductions in fertiliser use. The development and application of appropriate systems and tools to effectively quantify this spatial variability remain a challenge, coupled with management strategies that optimise the placement of amendments and account for the variability in other production limiting factors.

scholarly journals Simulated effects of gypsum amendment on phosphorus losses from agricultural soils

2012 ◽  
Vol 21 (3) ◽  
pp. 292-306 ◽  
Author(s):  
Elina Jaakkola ◽  
Sirkka Tattari ◽  
Petri Ekholm ◽  
Liisa Pietola ◽  
Maximilian Posch ◽  
...  
Keyword(s):  
Field Experiments ◽  
Clayey Soil ◽  
Agricultural Soils ◽  
Macropore Flow ◽  
Modified Model ◽  
Four Seasons ◽  
Complex Process ◽  
Phosphorus Losses ◽  
The Impact ◽  
Total P

Our objective was to incorporate the effects of gypsum on phosphorus (P) losses into the field-scale ICECREAM model and to simulate the treatment of 93 ha of clayey soil with gypsum in a catchment located in southern Finland. In addition to the gypsum effects, a macropore flow description was added to ICECREAM. First, a sensitivity analysis was performed for the new macropore parameters, retrieved from a literature survey. After this, the model was calibrated for a reference period by setting of the macropore parameters to correspond to the P losses observed in the catchment experiment. Next, the effect of gypsum was added to the model in line with laboratory and field experiments that suggested decreased P losses and changed hydraulic properties of the soil. Finally, the modified model was verified for four seasons after the gypsum amendment in the catchment experiment. The model was able to simulate the P losses in three out of the four seasons. According to the simulations, gypsum reduced total P losses by 44%. Although the effect of gypsum on P and erosion is a complex process, our relatively simple modifications to the ICECREAM model described the impact with reasonable accuracy. However, to increase confidence in the performance of the model, it should be tested under other environmental conditions.

scholarly journals Citizen science reveals unexpected solute patterns in semiarid river networks

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255411
Author(s):  
Erin Fleming Jones ◽  
Rebecca J. Frei ◽  
Raymond M. Lee ◽  
Jordan D. Maxwell ◽  
Rhetta Shoemaker ◽  
...  
Keyword(s):  
Citizen Science ◽  
Major Ions ◽  
Management Strategies ◽  
Source Area ◽  
Nutrient Status ◽  
Freshwater Ecosystems ◽  
High Variability ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Species ◽  
Relative Water

Human modification of water and nutrient flows has resulted in widespread degradation of aquatic ecosystems. The resulting global water crisis causes millions of deaths and trillions of USD in economic damages annually. Semiarid regions have been disproportionately affected because of high relative water demand and pollution. Many proven water management strategies are not fully implemented, partially because of a lack of public engagement with freshwater ecosystems. In this context, we organized a large citizen science initiative to quantify nutrient status and cultivate connection in the semiarid watershed of Utah Lake (USA). Working with community members, we collected samples from ~200 locations throughout the 7,640 km2 watershed on a single day in the spring, summer, and fall of 2018. We calculated ecohydrological metrics for nutrients, major ions, and carbon. For most solutes, concentration and leverage (influence on flux) were highest in lowland reaches draining directly to the lake, coincident with urban and agricultural sources. Solute sources were relatively persistent through time for most parameters despite substantial hydrological variation. Carbon, nitrogen, and phosphorus species showed critical source area behavior, with 10–17% of the sites accounting for most of the flux. Unlike temperate watersheds, where spatial variability often decreases with watershed size, longitudinal variability showed an hourglass shape: high variability among headwaters, low variability in mid-order reaches, and high variability in tailwaters. This unexpected pattern was attributable to the distribution of human activity and hydrological complexity associated with return flows, losing river reaches, and diversions in the tailwaters. We conclude that participatory science has great potential to reveal ecohydrological patterns and rehabilitate individual and community relationships with local ecosystems. In this way, such projects represent an opportunity to both understand and improve water quality in diverse socioecological contexts.

Transport of pesticides via macropores (IUPAC Technical Report)

2008 ◽  
Vol 80 (1) ◽  
pp. 105-160 ◽  
Author(s):  
Werner Kördel ◽  
Hans Egli ◽  
Michael Klein
Keyword(s):  
Preferential Flow ◽  
Measurement Techniques ◽  
Quantitative Information ◽  
Macropore Flow ◽  
Experimental Conditions ◽  
Pesticide Transport ◽  
Technical Report ◽  
Matrix Flow ◽  
Specific Assessment ◽  
A Site

This report provides an overview of the transport of solutes via macropores focusing on the practical relevance of the phenomenon. After a description of matrix flow and preferential flow in soil, information related to macropores, including their formation and measurement techniques, is briefly presented. Then, the influence of experimental conditions and of environmental and agricultural factors and pesticide properties is discussed, based on a statistical evaluation of all published studies offering sufficient quantitative information. Most of the analyzed parameters do not significantly influence the experimental pesticide losses. The groundwater ubiquity score (GUS) index turned out to be the most important compound property to describe substance losses through macropore flow. In a third section, tools for modeling pesticide transport through macropores are presented and critically evaluated. Results of the computer model MACRO, which is also used in the EU pesticide registration process, are compared with experimental losses. For five out of seven investigated pesticides (A-D, F), the simulated losses are in agreement with the experimental data. However, for two compounds with very low KOC values, MACRO overestimated the losses. Finally, the significance of pesticide transport via macropores for contamination of ground and surface water is assessed. Losses caused by macropore transport may considerably exceed losses caused by matrix transport at a specific site. Therefore, a site-specific assessment of pesticide leaching is needed.

Phosphorus leaching from pastures can be an environmental risk and even a significant fertiliser expense

2006 ◽  
pp. 293-296
Author(s):  
Matt R. Redding ◽  
A. Ghani ◽  
M. Kear ◽  
M. O'Connor ◽  
W. Catto
Keyword(s):  
Production Systems ◽  
Management Strategies ◽  
Phosphorus Leaching ◽  
Silt Loam ◽  
Retention Capacity ◽  
P Loss ◽  
Reactive Phosphate Rock ◽  
Pastoral Production ◽  
Phosphorus Losses ◽  
Pastoral Production Systems

While it is true that leaching is usually not a strong pathway for phosphorus (P) loss under many systems, is it true for all? Two studies reported in this paper sought to establish if significant phosphorus leaching can occur under normal pastoral production systems. Undisturbed-core lysimeters collected from a Wharekohe silt loam from Northland were treated with fertiliser P (reactive phosphate rock and superphosphate) then leached from August to November, 2005. In a second study, soil profiles under pasture for sheep/beef and dairy production in the catchments of the Rotorua lakes were sampled to depths of 1.5 m (28 sites), and soil Olsen P and P retention capacity index were determined down these profiles. Phosphorus losses from the Wharekohe soil to 25 cm depth were up to 33% of the P applied (superphosphate applications of 50 and 100 kg P/ha). Some Rotorua soils displayed enriched P concentrations at depth (to 1.5 m), often coupled with moderate or low P sorption capacities. If connectivity exists between leaching pathways and surface water bodies these observations indicate that alternative management strategies need to be developed and adopted for soils that leach significant quantities of P. The Wharekohe silt loam is one such soil. Keywords: phosphorus, leaching

Sustainable grazing systems for the Central Tablelands, New South Wales

2003 ◽  
Vol 43 (8) ◽  
pp. 861 ◽  
Author(s):  
D. L. Michalk ◽  
P. M. Dowling ◽  
D. R. Kemp ◽  
W. McG. King ◽  
I. J. Packer ◽  
...  
Keyword(s):  
Water Use ◽  
New South ◽  
Perennial Grass ◽  
Management Strategies ◽  
Cash Flows ◽  
Use Patterns ◽  
South Wales ◽  
Grazing Systems ◽  
Sustainable Grazing ◽  
Water Use Patterns

Pasture degradation is a major issue in the high rainfall zone (>600 mm) of temperate Australia. Characterised by a decline in the perennial grass component, this degradation is responsible for reduced livestock production and implicated in environmental problems, such as dryland salinity, through changed water-use patterns. This paper reports on a multi-disciplinary research program conducted at Carcoar in central New South Wales, one of 6 sites that comprised the Sustainable Grazing Systems National Experiment. The aim of the experiment was to develop more profitable and sustainable pasture systems by evaluating the impact of changes in the perennial grass component on animal production and water-use patterns. Tactical management strategies were evaluated on naturalised and sown perennial grass pastures and on chicory (Cichorium intybus), using a Merino ewe-based first cross lamb enterprise. Data presented showed that grazing deferment over summer, combined with reduced stocking rate, increased perenniality and reduced annual grass weeds compared with continuous grazing. Livestock performance, however, did not always follow trends in available perennial herbage mass. Naturalised and sown pastures were suitable for raising prime lambs, but only chicory had the capacity to finish lambs to market specification without supplementation. With respect to water-use patterns, sown perennial pastures were more successful than naturalised pastures in reducing leakage of water from the root zone, although this seemed to be related mostly to the abundance of the perennial grass in the pasture. From a sustainability perspective, continuously grazed pastures generated higher net cash flows, but had negative environmental impacts, whereas tactically grazed pastures had positive on- and off-farm impacts but lower net cash flows. The implications of these findings for incorporation into future management strategies for sustainable production in high rainfall environments are discussed.

scholarly journals Effectiveness of Cover Crops for Water Pollutant Reduction from Agricultural Areas

2021 ◽  
Vol 64 (3) ◽  
pp. 1007-1017
Author(s):  
Reid Christianson ◽  
Jordan Fox ◽  
Neely Law ◽  
Carol Wong
Keyword(s):  
Water Quality ◽  
Cover Crops ◽  
Cover Crop ◽  
List Type ◽  
Loss Reduction ◽  
Nutrient Losses ◽  
Phosphorus Loss ◽  
Dissolved Phosphorus ◽  
Freeze Thaw ◽  
Phosphorus Losses

HighlightsNitrogen loss reduction due to a cover crop tends to improve with increased cover crop biomass production.Mixed phosphorus loss reduction results in cold climates where freeze-thaw cycles occur and can increase dissolved phosphorus losses.Cereal rye was the primary cover crop studied and tended to provide the most water quality benefits.Abstract. Mitigating nutrient losses from agricultural fields retains these nutrients for subsequent crop production and reduces the risk to downstream water quality. This study evaluated the impact of cover crops, as part of an annual cropping system, on reducing nutrient losses and enhancing water quality. Cover crop literature focusing on water quality was reviewed to determine important factors regarding cover crop performance and cost. Results show that a grass-based cover crop and mixes with grasses tend to increase nitrate loss reduction (40%) compared to legumes (negligible). Biomass growth was also important, with early seeding or growth of a cover crop in areas with increased growing degree days enhancing performance. For phosphorus loss, benefits did not necessarily increase with increasing biomass. Further, dissolved phosphorus concentrations may increase due to freeze-thaw cycles (23%), although overall dissolved phosphorus losses tend to decrease due to less runoff (34%). Cover crop implementation costs ranged from a savings of $25 to $44 ha-1 year-1 before soybeans and corn, respectively, when implementing a cover crop for five straight years to a cost of $193 ha-1 year-1. Including a cover crop in annual crop rotations with adequate time in the fall for germination and growth can reduce nitrogen and phosphorus losses from production agriculture to help meet water quality goals across the U.S. Keywords: Catch crop, Nitrogen, NRCS, Phosphorus, Practice Code 340, USDA, Water quality.

DRAINMOD-P: A Model for Simulating Phosphorus Dynamics and Transport in Drained Agricultural Lands: II. Model Testing

2021 ◽  
Vol 64 (6) ◽  
pp. 1849-1866
Author(s):  
Manal H. Askar ◽  
Mohamed A. Youssef ◽  
Dean L. Hesterberg ◽  
Kevin W. King ◽  
Aziz Amoozegar ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Preferential Flow ◽  
Model Performance ◽  
Water Quality Modeling ◽  
List Type ◽  
Macropore Flow ◽  
Major Pathway ◽  
Phosphorus Loss ◽  
Particulate Form ◽  
Subsurface Drains

HighlightsDRAINMOD-P was tested using a dataset from a drained field with desiccation cracks.Surface and subsurface phosphorus losses were mainly in the particulate form.Surface runoff was a major pathway for phosphorus loss in this field.The model performance in predicting edge-of-field phosphorus loss is promising.Abstract. The recently developed phosphorus (P) model DRAINMOD-P was tested using a four-year dataset from a subsurface-drained field in northwest Ohio with significant potential for desiccation cracking or preferential flow. The model satisfactorily predicted subsurface drainage discharge, with a monthly Nash-Sutcliffe efficiency (NSE) of 0.59 and index of agreement (IOA) of 0.89. Lack of annual water budget closure was reported and was likely caused by uncertainty in measured surface runoff and/or modeling approaches representing macropore flow. More than 80% of predicted surface and subsurface P losses were in the particulate form. Surface runoff was the major pathway for P loss, contributing 78% of predicted total P (TP) load. On average, predicted macropore flow represented about 15% of drainage discharge and contributed 21% of DRP loss via subsurface drains. The performance of DRAINMOD-P in predicting monthly dissolved reactive P and TP losses through subsurface drains can be rated as poor (NSE = 0.33 and IOA = 0.60) and very good (NSE = 0.81 and IOA = 0.95), respectively. DRAINMOD-P demonstrated potential for simulating P fate and transport in drained cropland. More testing is needed to further examine newly incorporated hydrological and biogeochemical components of the model. Keywords: Agricultural drainage, Edge-of-field phosphorus load, Macropore flow, Phosphorus model, Sediment yield, Water quality modeling.

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