Physical Sciences and Mathematics Commons^™

Phosphorus Transfer To River Water From Grassland Catchments In Ireland, H. Tunney, P. Jordan, G. Kiely, R. Moles, G. Morgan, P. Byrne, W. Menary, K. Daly

IGC Proceedings (1997-2023)

In Ireland it is estimated that at least half of phosphorus (P) loss to water is from agricultural sources and National and European Union policy and legislation aim at reducing phosphorus (P) loss to water in order to reduce eutrophication. In Ireland, the average soil test P (STP) levels increased ten-fold, from less than 1 to over 8 mg Morgan P per l soil over the past 50 years, reflecting increased P inputs in fertiliser and animal feed. One of the main objectives of this three-year research programme, started in 2001, was to investigate P loss to water in grassland …

Grazing Management Impacts On The Riparian Zone And Water Quality, S. R. Aarons, A. Melland, C. J. P. Gourley

IGC Proceedings (1997-2023)

Inappropriate farm management activities such as stock access to creeks, and poor fertiliser and effluent management can negatively impact riparian zones and waterways, contributing to increased in-stream nutrient, sediment and microbiological loads and loss of riparian biodiversity, amongst other impacts. Nutrient budgets for dairy systems indicate that on-farm nutrient accumulation and redistribution is common (Gourley 2004), which in large part is due to the uneven distribution of dairy cow dung and the nutrients they contain (Aarons et al., 2004). The 'Gippsland Dairy Riparian Project Environmental Monitoring module' was established in Jan. 2003 to monitor the impact of …

Influence Of P Fertility And Grazing On Plant Species In A Temperate Australian Pasture, Jacqueline O. Hill, R. J. Simpson, A. D. Moore, J. T. Wood, D. F. Chapman

IGC Proceedings (1997-2023)

Graziers in temperate Australia are increasing their use of P fertiliser so they can run more stock and maintain profitability. However, intensification changes grassland botanical composition and perennial grass cover can be reduced. Perennial grasses are important because they improve production stability, reduce deep drainage and slow the rate of soil acidification. This study examined how P fertility and grazing affected the botanical composition of pasture based on Phalaris aquatica, a key perennial grass in south-eastern Australia.

Mechanical Aeration And Liquid Dairy Manure: Application Impacts On Grassland Runoff Water Quality And Yield, T. J. Basden, S. B. Shah, J. L. Miller

IGC Proceedings (1997-2023)

Wet weather on heavy soils reduces oxygen availability in the root zone and reduces forage yields. Mechanical aeration can improve forage yield in these soil conditions. Research has shown that under certain conditions, mechanical aeration can increase yield by improving drainage and aeration (Davies et al., 1989); aeration can also increase depression, storage and infiltration thus reducing surface runoff and improving nutrient distribution in the root zone. Aeration on sloping, fertilised grassland can provide environmental (Douglas et al., 1995) and agronomic benefits. The objectives of this study were to evaluate the runoff water quality and agronomic impacts of …

Grazing Effects On Some Soil Characteristics In Lar Rangelands, S. A. Javadi, M. Jafari, Gh. Zahedi

IGC Proceedings (1997-2023)

Heavy grazing pressures jeopardise the sustainability of the ecosystem by reducing soil fertility (Dormaar et al., 1998). Different results have been reported of grazing intensities on soil chemical properties, which stem from climate, soil, vegetation, management and kind of animal (Dormaar et al., 1998; Javadi, 2003; Sanadgool, 2002).

Investigating The Role Of Plant Traits And Interactions In Emergent Wetland Nutrient Removal, Andrew Ryan Sample

Theses and Dissertations

Increasing wetland restoration in the Lower Mississippi Alluvial Valley has been identified as a method to reduce nutrient loading in the Gulf of Mexico. Wetlands have historically been used to treat water through processes facilitated by wetland plants, and relatively few species and plant traits have been identified as important in carrying out these processes. This study focuses on some of those species and traits and aims to identify species differences and plant traits that may be important for wetland nutrient mitigation. Chapter I provides background information on nutrient pollution, wetland biogeochemical mechanisms for nutrient sequestration, and the focal species …

Leaf Dry Matter Content Of Native Grassland Species Under Contrasting N And P Supply, P. Cruz, C. Jouany, Jérome M. Enjalbert, Michael Duru

IGC Proceedings (1997-2023)

The management of native grasslands - herbaceous vegetation with a broad diversity of flora and a large range of uses - must meet the requirements of environmental conservation and improvement of the quality of agricultural production. For this purpose we need tools for diagnosing the state of the vegetation in order to design, evaluate, and apply management practices to attain these objectives. These tools must be simple and quick to use and should not require botanical skills. Leaf dry matter content (LDMC) has been proposed as a good indicator of both fertility gradients and species preference for habitats (Cruz et …

Potentialities Of Near Infrared Spectroscopy To Assess Nitrogen, Phosphorus And Potassium Nutrient Status Of Grasslands In The Reunion Island, Philippe Lecomte, Vincent Blanfort, Michael Duru, P. Thomas, P. Grimaud

IGC Proceedings (1997-2023)

Controlled mineral fertilisation practices are an important component for sustainable management of grasslands. The assessment of available nutrients for plants and the general recommendations on the level of phosphorus and potassium to apply to grasslands are classically based on classical soil analysis and average regional levels. For nitrogen, mid or long term recommendations cannot easily be derived solely from soil composition, because it may be rapidly leached from the soil. Recent approaches tended to show that herbage plant N (Lemaire & Gastal, 1997), P, K (Duru & Huché, 1997) mineral analyses associated with actual biomass measurement could be useful for …

Heterogeneous Nutrient Distribution Across Dairy Grazing Systems In Southeastern Australia, C. J. P. Gourley, I. Awty, P. A. Durling, J. Collins, A. Melland, S. R. Aarons

IGC Proceedings (1997-2023)

The Australian dairy industry is largely based on a grazed pasture system, although most cows also consume substantial amounts of imported feed (Fulkerson & Doyle 2001). This trend is expected to increase as the Australian dairy industry continues to intensify. Fertiliser inputs of nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) are still viewed as necessary to maintain adequate pasture and milk production despite the fact that most dairy farms are in net positive balance for all of these nutrients (Reuter 2001). Nutrient losses from dairy farming regions and eutrophication of waterways has gained strong public and political attention …

Reasons For The Premature Decline In Astragalus Adsurgens Stands In Kerqin Sandy Land, Qizhong Sun, Z. L. Wang, J. G. Han, Y. W. Wang, G. R. Liu

IGC Proceedings (1997-2023)

Diseases partly account for reductions in Astragalus adsurgens stand longevity. The effect of some cultural practices on the control of pests and diseases have been reported (Hou, 1986; Nan, 1996), but few reports have detailed the relationship among soil fertiliser status, diseases and premature stand decline. This study was conducted to investigate these relationships in order to extend the longevity of Astragalus adsurgens stands.

Heterogeneous Nutrient Distribution Across Dairy Grazing Systems In Southeastern Australia, C. J. P. Gourley, I. Awty, P. A. Durling, J. Collins, A. Melland, S. R. Aarons

IGC Proceedings (1997-2023)

The Australian dairy industry is largely based on a grazed pasture system, although most cows also consume substantial amounts of imported feed (Fulkerson & Doyle 2001). This trend is expected to increase as the Australian dairy industry continues to intensify. Fertiliser inputs of nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) are still viewed as necessary to maintain adequate pasture and milk production despite the fact that most dairy farms are in net positive balance for all of these nutrients (Reuter 2001). Nutrient losses from dairy farming regions and eutrophication of waterways has gained strong public and political attention …

Reasons For The Premature Decline In Astragalus Adsurgens Stands In Kerqin Sandy Land, Qizhong Sun, Z. L. Wang, J. G. Han, Y. W. Wang, G. R. Liu

IGC Proceedings (1997-2023)

Diseases partly account for reductions in Astragalus adsurgens stand longevity. The effect of some cultural practices on the control of pests and diseases have been reported (Hou, 1986; Nan, 1996), but few reports have detailed the relationship among soil fertiliser status, diseases and premature stand decline. This study was conducted to investigate these relationships in order to extend the longevity of Astragalus adsurgens stands.

Breeding Milestones Correspond With Changes To Wheat Rhizosphere Biogeochemistry That Affect P Acquisition, Rebecca Kay Mcgrail, David A. Van Sanford, David H. Mcnear Jr.

Plant and Soil Sciences Faculty Publications

Breeding wheat (Triticum aestivum L.) has resulted in small gains in improved nutrient acquisition and use as numerous traits are involved. In this study, we evaluated the impact of breeding on P-acquisition and identified both plant and soil variables that could be used to inform the selection of germplasm with increased P acquisition efficiency. We previously screened a historic panel of winter wheat cultivars for root system architecture and root tip organic acid content when grown in P-deficient solution/agar and used these characteristics together with breeding history to develop a predicted P extraction potential (PEP). We tested the validity …

Better Dairy Farm Management Increases The Economic Return From Phosphorus, J. D. Morton

IGC Proceedings (1997-2023)

Some 60% of New Zealand dairy farms on allophanic and sedimentary soils have soil Olsen phosphorus (P) levels to 75 mm depth above the target range for near-maximum pasture production of 20-30 µg/ml (Roberts & Morton 1999). For an economic response in milksolids (MS) production from high Olsen P, the pasture needs to be capable of high production, and the extra pasture grown be converted to milk. This paper seeks to justify this contention and outline some of the farm management practices required to achieve it.

Grassland Productivity And Water Quality: A 21st Century Issue, David M. Nash, P. M. Haygarth

IGC Proceedings (1997-2023)

1. Irrigation and other changes to the hydrological cycle can increase soil and water salinity.
2. Primary salinisation is a natural process that affects much of Europe, Asia, Africa, the Americas and Australia. Secondary salinisation is caused by human activities such as irrigation and land clearing that mobilise salt stored in the soil.
3. The critical water contaminants exported from grasslands are nitrogen, phosphorus, potential pathogens and sediment.
4. The mechanisms responsible for diffuse pollution from grasslands and mitigation strategies are most effectively investigated using a ‘source-mobilisation-transport’ framework.
5. There is a lack of coherent interaction across discipline boundaries that links pollutant sources to impact. …