Plant Sciences Commons^™

Soil Aggregate Dynamics, Particulate Organic Matter And Phosphate Under Dryland And Irrigated Pasture, J. T. Scott, L. M. Condron, R. W. Mcdowell

IGC Proceedings (1997-2023)

Soil aggregate formation and turnover affects the rate of occlusion or release of soil organic matter and therefore the availability for mineralisation or stabilisation of soil carbon (C) and phosphorus (P). Furthermore, differences in soil type, management and the quantity and quality of organic inputs can affect aggregate turnover rates (Six et al., 2000). Under pastoral farming the ratio of coarse particulate organic matter (inter-POM) inside macroaggregates but outside microaggregates to fine POM (intra-POM) within microaggregates may provide an indication of physical processes influencing mineralisation and stabilisation of soil C and organic P (Po). Our aim was to determine …

Fire And Nutrient Cycling In Shortgrass Steppe Of The Southern Great Plains, Usa, P. L. Ford, C. S. White

IGC Proceedings (1997-2023)

Fire in semi-arid grasslands releases nutrients bound up in organic matter and accelerates the rate of decomposition in the soil. This research experimentally tested effects of season and frequency of fire on nutrient cycling dynamics in shortgrass steppe. The objective was to identify if fire treatments have the ability to increase potential grassland productivity relative to untreated ‘reference condition’ grassland. Many such studies focus on short-term, direct effects of fire. However, this study is part of a long-term, 18-year study examining both direct, and indirect effects of fire in the growing vs. dormant season at return intervals of 3, 6 …

Maximising Slurry Crop Available Nitrogen Utilisation In Grassland Systems, J. R. Williams, E. Sagoo, B. J. Chambers, J. Laws, D. R. Chadwick

IGC Proceedings (1997-2023)

In the UK, approximately 90 million tonnes of animal manure containing ca 450,000 tonnes of nitrogen (N) are recycled to agricultural land each year. The efficient utilisation of manure N can save farmers money and reduce diffuse air (ammonia) and water (nitrate) pollution. For slurries, bandspreading techniques (e.g. trailing shoe and trailing hose) can improve N utilisation by reducing ammonia volatilisation losses compared with conventional broadcast applications. They also provide increased spreading opportunities in spring/summer as slurry is placed in a band on the soil surface limiting herbage contamination, which can reduce the need to apply slurry in the autumn/early …

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 …

Denitrification Under Pastures On Permeable Soils Helps Protect Ground Water Quality, M. P. Russelle, B. A. Browne, N. B. Turyk, B. Pearson

IGC Proceedings (1997-2023)

Pastures have been implicated in ground water contamination by nitrate, especially in humid regions with thin or sandy soils (Stout et al., 2000). Significant losses can occur even under low N input, because available N from excreta patches often exceeds plant uptake capacity. Lack of evidence that appreciable nitrate leaching was occurring in established Midwestern USA pastures led us to test the hypothesis that denitrification was preventing or remediating nitrate loading. Higher denitrification rates have been found in the relatively limited number of trials since Ball & Ryden (1984) first reported the significance of this process in pastures.

Assessment Of Nitrogen Nutrition Status Of Grasses Under Water Deficit And Recovery, V. G. Dugo, Jean-Louis Durand, F. Gastal

IGC Proceedings (1997-2023)

Grasslands are rarely irrigated. They are therefore systematically submitted to more or less severe water deficits: as well as mineral deficiencies, water scarcity often also results in a reduction of nitrogen (N) status. Although identified some time ago, qualitatively, the interaction with N still remains difficult to take into account in quantitative analyses of crop physiology under water deficits. This paper illustrates how the nitrogen (N) status of the crop changes under water deficits. A N nutrition index (INN) was defined as the ratio of the actual N concentration of forage with the theoretical N concentration under optimal conditions, the …

Improving Nutrient Supply Of Grassland Soil, G. Füleky, M. Orbán

IGC Proceedings (1997-2023)

In the Southern corner of the Eastern Carpathian Mountains is located the hilly region of Barcaság. The total agricultural area is 180 thousand ha of which 90 thousand ha is grassland. The maximum yield of natural grassland does not exceed 1.2 t ha^-1 hay. The aim of this work is to find appropriate fertiliser and liming rates to increase the hay yield and improve the soil nutrient supply.

Safe - A Tool For Assessing The Sustainability Of Agricultural Systems: An Illustration, X. Sauvenier, C. Bielders, M. Hermy, E. Mathijs, B. Muys, J. Valckx, N. Van Cauwenbergh, M. Vanclooster, E. Wauters, A. Peeters

IGC Proceedings (1997-2023)

SAFE (Framework for Assessing Sustainability levels) is a tool for evaluating the sustainability of agricultural systems and uses a hierarchical framework populated with indicators objectively selected by multicriteria evaluation. Indicators are measured at field, farm and landscape scales and progressively integrated into a global sustainability index (SI). SAFE is illustrated below with results on a field scale from a farm site.

Foliar Application Of Acetic Acid And Effectiveness Against Drought At Different Time Points In Soybean Development, Miranda Rudolph

Scholars Week

Abstract

Drought is arguably the most serious environmental factor affecting crop production today. A plants response to drought stress is extremely complex, affecting numerous metabolic pathways that are all interconnected in their responses. Due to this complex nature, scientists do not fully understand the implications of different treatments and how they affect these processes. Acetic acid has been shown to improve plant growth and resistance to drought stress, but exactly how it accomplishes this is also unknown. Soybeans (Glycine max) are one of the most important crops worldwide and can suffer significant yield loss due to drought stress. As climate …

Genome‑Wide Association Analyses Of Leaf Rust Resistance In Cultivated Emmer Wheat, Dhondup Lhamo, Qun Sun, Qijun Zhang, Xuehui Li, Jason D. Fiedler, Guangmin Xia, Justin D. Faris, Yong‑Qiang Gu, Upinder Gill, Xiwen Cai, Maricelis Acevedo, Steven S. Xu

Department of Agronomy and Horticulture: Faculty Publications

Leaf rust, caused by Puccinia triticina (Pt), constantly threatens durum (Triticum turgidum ssp. durum) and bread wheat (Triticum aestivum) production worldwide. A Pt race BBBQD detected in California in 2009 poses a potential threat to durum production in North America because resistance source to this race is rare in durum germplasm. To find new resistance sources, we assessed a panel of 180 cultivated emmer wheat (Triticum turgidum ssp. dicoccum) accessions for seedling resistance to BBBQD and for adult resistance to a mixture of durum-specific races BBBQJ, CCMSS, and MCDSS in the field, and genotyped …

Nitrogen Response Of Spring And Winter Wheat To Biosolids Compared To Chemical Fertiliser, W. Kato, O. T. Carton, D. Mcgrath, H. Tunney, W. E. Murphy, P. O'Toole

IGC Proceedings (1997-2023)

Irish sewage sludge production was over 30,000 t/year in the 1990s (EPA, Ireland, 2003). Application to agricultural land is a management option for this organic material as it results in the recycling of the nutrients they contain for crop production. The EU Directive (91/271/EEC) encourages the recycling of sewage sludge as biosolids to agriculture. However, up to 1999, only about 5 % of biosolids produced was applied to agricultural land. In this study, several biosolids and a chemical fertiliser were used to assess N availability for spring and winter wheat (Triticum aestivum,) production in a pot experiment.

Supplementation Of Cattle With Rock Phosphate And Urea Treated Straw To Improve Manure Quality And Crop Yields In The Sahel Zone Of Senegal, Maimouna Cissé, M. N’Diaye, C. M. N’Dione

IGC Proceedings (1997-2023)

Mineral deficiencies are a major constraint in improving animal production and crop yield in the Sahel zone (Cissé et al., 1996). Millet (Pennisetum glaucum) and groundnut (Arachis hypogaea,) are two major food and cash crops in this zone. The purpose of this study was to assess effects of supplementing grazing cattle with rock phosphate and nitrogen enriched diets on animal performances, and the effects of the application of their manure on crop yield in a pearl millet-groundnut rotational system located in N Senegal.

Total Sulphur Content And N:S Ratio As Indicators For S Deficiency In Grasses, M. Mathot, R. Lambert, B. Toussaint, A. Peeters

IGC Proceedings (1997-2023)

Recently, sulphur (S) deficiencies have been observed throughout Europe (Zaoh et al., 2002). Grassland covers about 50 % of the agricultural area in the European Union. In cutting regimes exports are ca 30 kg S/ha per year. Atmospheric depositions provide, at the present, ca15 kg S/ha per year and S is not considered in fertiliser programmes. Without fertilisation, the S balance at the field scale is negative and therefore some cut swards could be S deficient. Tools for determining whether the grassland is deficient are required. The utilisation of indicators based on S content and N:S ratio was …

Study Of Soil Characteristics To Estimate Sulphur Supply For Plant Growth, M. Mathot, R. Lambert, B. Toussaint, A. Peeters

IGC Proceedings (1997-2023)

During the last decades, sulphur (S) deficiencies have been observed throughout Europe (Zaoh et al., 2002). Accurate estimation of S supply by the soil-atmosphere system is required to give advice for S fertilisers. Soil is an important S source for plants and it is therefore important to evaluate supply by the soil to avoid deficiencies or excessive S fertilisation. The purpose of this preliminary study was to estimate which soil characteristics could be useful for predicting S supply by soil. Lolium multiflorum was grown on different soils in a growth chamber and S supply was correlated with soil characteristics.

Organic Matter Transformation Processes Of Soils In Native Steppe Grass Communities, E. Forró

IGC Proceedings (1997-2023)

It has been well known that higher plant density provides more effective protection for soils. However, the influence of different vegetation on the soil properties has been less well recognised. The high density of grass communities, a high number of plant species and density of roots have advantageous effects on soil properties and conditions, particularly on the organic matter cycling and structure of soils.

Characterisation Of Soil Organic Matter From Pensacola Bahiagrass Pastures Grazed For Four Years At Different Management Intensities, J. C. B. Dubeux Jr., Lynn E. Sollenberger, N. B. Comerford, Ana C. Ruggieri, K. M. Portier

IGC Proceedings (1997-2023)

Soil fertility and agricultural system sustainability depend upon soil organic matter (SOM), particularly in the tropics, because of highly weathered soils and low fertiliser inputs. Because of the beneficial effects of SOM on chemical, physical, and biological soil properties, Greenland (1994) suggested that SOM is an indicator of agro-ecosystem sustainability. Pasture management may affect SOM by altering the production/decomposition ratio of residues (Johnson, 1995). The objective of this study was to characterise the SOM of Pensacola bahiagrass pastures grazed for four years at a range of management intensities.

Implications For N Transformations In Acidic Soils Of Replacing Annual-Based Legume Pastures With Lucerne-Based Pasture In Dryland Farming Systems Of Southern Australia, I. R. P. Fillery

IGC Proceedings (1997-2023)

The supply and demand for nitrogen (N) in annual-based pasture-crop rotations in southern Australia is often poorly synchronised, leading to large losses of inorganic N (Fillery, 2001). Perennial pasture species, particularly lucerne, are being recommended to minimise dryland salinity. The implications for N cycling of using lucerne in place of annual legumes on acidic sandy soils that are widespread have not been widely studied. Lucerne is less tolerant of acidity and could fix less N than annual legumes. Lucerne root residues mineralise at slower rates than annual pasture residues with lower N release to subsequent wheat crops (Bolger et al …

N-Mineralisation And Phosphorous: Important Elements In Decision Support For Grassland Systems, A. L. Nielsen, C. C. Hoffmann

IGC Proceedings (1997-2023)

Leaching of N and P from extensively managed grasslands on organic soils varies considerably. In environmentally sensitive areas it is important to diminish leaching by appropriate agricultural management. In Denmark low grazing intensity and management without fertilisation have been given a high priority. The type of soil has not been equally in focus, and it seems that the effect of cutting, compared with grazing, results in a higher removal of nutrients (e.g. Benke et al., 1992) can be used more strategically. The objective of this case study was to combine data from management strategies with data from leaching studies …

Nitrogen Mineralisation In Situ And In Controlled Environment, F. Pálmason

IGC Proceedings (1997-2023)

Net mineralisation may be underestimated by in situ soil core methods for at least two reasons: (1) absence of plant N uptake in the soil cores, causing higher immobilisation than in intact soil. Schimel & Bennet (2004) thus concluded that plants compete effectively with microbes, as strongly indicated by cases, where net mineralisation was lower than plant uptake. (2) Gaseous losses of N₂O in closed cylinders can lead to underestimation especially during long incubation periods, Abril et al. (2001) and Vor & Brumme (2002).

Seasonal Changes In The Ratio Of Microbial Biomass P To Total P In Soils Of Grazed Pastures, M. Kaneko, Y. Kurokawa, H. Tanaka, S. Suzuki

IGC Proceedings (1997-2023)

Phosphorus (P) utilisation efficiency in pasture soils is higher than in arable soils. Because there is a considerable amount of microbial biomass in the root mat layer, which is peculiar to permanent pasture, the microbial biomass P (MBP) contribution may be important in supplying soil P to pasture plants (Chen et al., 2000; He et al., 1997). In the present study, we investigated seasonal changes in MBP and other forms of P relative to total soil P in two pastures in which P uptake was estimated to be different.