Laboratory Development of a Passive Proportional Sampler for Overland FlowStudies in Agricultural Fields

peer-reviewedWater-quality in many rivers remains poor and needs to be improved. Diffuse pollution continues to cause difficulties. Some instruments are available which can monitor pollution of rivers from land. They allow measurement and sampling of overland flow (OLF), but they do not offer the precision required (proportional sampling and samples 0.1% of OLF). A laboratory unit was constructed to mimic instrument performance in the field. This was used to test three sampler designs. A V-notch weir was used in the first sampler and a Sutro weir in the second and third as this unit possessed a proportional discharge to head ratio, which the Vnotch weir did not have. Other parameters investigated included ground slope, sampler slope, pipe size and port location. The remaining issues of nozzle size (0.7, 1.0 and 2.0 mm), the number of 1.0 mm nozzles and the effect of aspiration were investigated. The arrangement with the Sutro weir and three 1.0 mm nozzles in series gave proportional discharge and the target low sampling rate of 0.1%. This will allow the calculation of sediment and chemical losses for the monitored area and will put the loss in context with other losses in a catchment

A note on the conservation characteristics of baled grass silages ensiled with different additives.

peer-reviewedThe effects of contrasting conventional silage additives on chemical composition, aerobic stability and deterioration, and mould development in baled silage were investigated. Herbage from a grassland sward was wilted for 24 h and treated with acid (formic or sulphuric), sugar (molasses), bacterial (Lactobacillus plantarum, L. plantarum + Serratia rubidaea + Bacillus subtilis, or L. buchneri) or sugar + bacterial (molasses + L. plantarum) additives prior to baling and wrapping. Silage made without an additive preserved well and had a low incidence of mould growth, and the effects of additives were minor or absent. It is concluded that little practical benefit was realised when conventional additives were applied to wilted, leafy, easy-to-ensile grass prior to baling and ensilage

Conservation characteristics of baled grass silages differing in duration of wilting, bale density and number of layers of plastic stretch-film

peer-reviewedThe effects of duration of wilting, bale density and number of layers of plastic stretchfilm used to wrap bales on the conservation characteristics of baled grass silage was investigated. Grass from the primary growth of a Lolium perenne dominant sward was wilted for 24, 48 or 72 h. For each duration of wilting, 54 cylindrical bales (1.2 m nominal diameter) were made with the baler at a high or low density setting for alternate bales. Bales were wrapped with 2, 4 or 6 layers of plastic stretch-film and stored outdoors for 295 days. Two layers of plastic stretch-film resulted in inferior preservation, lower digestibility and extensive mould growth and deteriorated silage. Substantial improvement occurred to each of these characteristics from applying four layers of stretch-film (P<0.05), while six layers of stretch-film brought little further improvement. When four or six layers of stretch-film were used, extensive wilting restricted fermentation and improved the standard of preservation with the apparently difficult-to-preserve herbage used in this experiment. However, under the anaerobic conditions provided by four or six layers of stretch-film neither progressive wilting nor bale density had a major effect on digestibility, or the extent of surface mould growth or deteriorated silage. It can be concluded that a minimum of four layers of conventional black plastic stretch-film were required to achieve suitably anaerobic conditions, and that the additional benefits from six layers were small. Once anaerobic conditions were achieved, extensive wilting improved the conservation characteristics of baled grass silage made from a difficult-to-preserve crop, whereas bale density had little impact

The Application of Harvester -Mounted Forage Yield Sensing Devices.

End of Project ReportThe development and application of precision agriculture technology to forage crops offers scope for improved management practices and targeting of inputs. In particular, the ability to measure forage throughput on a harvester would form the basis for improved management decisions and the ability to exploit precision agriculture technology, including accurate application of forage additives. The aim of this project was to develop a forage throughput sensor and to use that sensor to record yield variability and to accurately control additive application. Following preliminary trials, a force sensing plate placed in a forage harvester chute was developed and assessed. A very good relationship between sensed throughput and measured throughput was achieved, with regression coefficients of between 0.88 and 0.96 recorded in a series of trials. The relationship was established on a fresh-weight basis. Calibration could present difficulties in practice. The forage throughput sensor was linked to a GPS positioning system and a modified yield monitor/recording system to facilitate the measurement of yield variability in the field. Considerable difficulties were encountered with compatibility of the various components, including the analysis software. While a forage yield map was created and illustrated the levels of yield variability within a field, the need for simultaneous on-harvester dry matter sensing was apparent. A throughput-based additive application control system was designed, developed and tested. The unit performed satisfactorily, resulting in less variation in the quantity of additive applied to harvested grass compared to conventional application systems. In conclusion, there is scope for the application of precision agriculture technology, based on forage yield sensing, on grassland farms. However, there are many differences between the adoption of this technology on grassland farms compared to arable farms. In particular, yield-sensing accuracy is unlikely to be as good, and the need for simultaneous DM sensing is critical. Forage yield sensors will be commercialised soon. There will then be a need to evaluate these systems and the application of precision agriculture technology to grassland systems

Manipulating the ensilage of wilted, unchopped grass through the use of additive treatments

peer-reviewedBaled silage composition frequently differs from that of comparable conventional precision-chop silage. The lower final concentration of fermentation products in baled silage makes it more conducive to the activities of undesirable microorganisms. Silage additives can be used to encourage beneficial microbial activity and/or inhibit detrimental microbial activity. The experiment was organised in a 2 (chop treatments) × 6 (additive treatments) × 2 (stages of ensilage) factorial arrangement of treatments (n = 3 silos/treatment) to suggest additive treatments for use in baled silage production that would help create conditions more inhibitory to the activities of undesirable microorganisms and realise an outcome comparable to precision-chop silage. Chopping the herbage prior to ensiling, in the absence of an additive treatment, improved the silage fermentation. In the unchopped herbage, where the fermentation was poorer, the lactic acid bacterial inoculant resulted in an immediate increase (P < 0.001) in lactic acid concentration and a faster decline (P < 0.001) in pH with a subsequent reduction in butyric acid (P < 0.001) and ammonia-N (P < 0.01) concentrations. When sucrose was added in addition to the lactic acid bacterial inoculant, the combined treatment had a more pronounced effect on pH, butyric acid and ammonia-N values at the end of ensilage. The formic acid based additive and the antimicrobial mixture restricted the activities of undesirable microorganisms resulting in reduced concentrations of butyric acid (P < 0.001) and ammonia-N (P < 0.01). These additives offer a potential to create conditions in baled silage more inhibitory to the activities of undesirable microorganisms.A Teagasc Walsh Fellowship Research Scholarship awarded to J. McEniry supported this study

Machinery costs on tillage farms and the development of decision support systems for machinery investments/use on farms.

End of Project ReportCosts and benefits associated with the use of farm machinery are difficult to calculate. A research programme was established to highlight the area of machinery costs and to provide information on which to base mechanisation decisions. A machinery cost survey was the central part of the programme which collected detailed machinery cost information from 40 arable farms over a period of three years. Costing methods were developed to provide an annual per-hectare cost for each machine over its ownership period. An average annual machinery cost figure of £194/ha, excluding labour, was recorded. Costs varied from £93/ha to £340/ha between farms. Depreciation and interest accounted for almost 60% of the total costs figure. Larger farms (>160 ha) had lower costs and less cost variation than smaller- and medium-sized farms. They were more machinery efficient, with lower levels of machinery investment per hectare. Smaller- and medium-sized farms had much greater cost variation with many farms being over-mechanised, resulting in excessive machinery costs. The importance of selecting an appropriate mechanisation policy for individual farm situations was evident. Using information from the survey to select appropriate costing methodology from other research, a simple cost-prediction computer program was developed. This allows costs for an individual machine at any use level to be estimated. This program was used to evaluate various mechanisation options on 40, 100 and 240 ha farms. The program was then redeveloped for use by the advisory service. It is a decisionsupport type program which requires input from a trained operator with experience of mechanisation. It should prove useful in determining farm mechanisation policies against a background of changing mechanisation technology, farm labour supply and potential price-support reductions.Cereals Levy Farmer Fund

Baled Silage - Development Of Reliable Baled Silage Systems

End of Project ReportBaled silage is now made on two-thirds of all farms in Ireland, and accounts for one third of all silage made. It is particularly prevalent as the primary silage-making system on both beef farms and smaller-sized farms. However, it is also widespread as a second silage-making system on many other farms. The series of experiments contained in this report were conducted as part of a collaborative EU Structural Funds supported research project jointly carried out between the Teagasc research centres at Grange and Oak Park. Some of the research was also conducted in collaboration with the Botany Dept. at University College Dublin.European Union Structural Funds (EAGGF

The microbiological and chemical composition of baled and precision-chop silages on a sample of farms in County Meath

peer-reviewedA Teagasc Walsh Fellowship awarded to J. McEniry supported this study.Baled and precision-chop silages were examined on a sample of farms in the Irish midlands to determine microbiological and chemical composition at feedout. Silage making practices and chemical composition were similar to those in national surveys. Wilting was an integral part of baled silage production and was reflected in a more restricted fermentation (higher pH and water-soluble carbohydrates, with lower fermentation acids and buffering capacity) compared to precision-chop silage. Yeast numbers were higher in baled silage, suggesting a more aerobic environment within the bale. Although the fermentation appeared similar in the outer and inner horizons of baled silage, yeast, lactic acid bacteria and Enterobacteria numbers were higher in the outer horizon suggesting less exacting anaerobiosis adjacent to the surface of the bale

Effect of soil aeration in minimising/alleviating soil compaction and sward damage in grassland.

End of Project ReportDue to increased farmer interest in mechanical spiking as a method for alleviating soil compaction in grassland, a series of experiments was conducted from 1995- 98. Experiments comparing single (one year only in spring and autumn) or annual spiking in spring and autumn were conducted at: Oak Park, Carlow; Knockbeg, Co. Laois; Kilmaley, Co. Clare; and Solohead, Co. Tipperary under grazing and silage management regimes. While there were differences between spiked and unspiked treatments, these were usually small and inconsistent. The results of these experiments show that routine spiking of grassland is unlikely to produce any yield benefits. Spiking may be beneficial where specific shallow compaction problems occur but is unlikely to alleviate the effects of wheel traffic.Dairy Levy Farmer Fund

A study of cultivation and sowing systems for cereals.

End of Project ReportDue to the pressure on cereal margins growers are seeking ways of reducing their costs of production. Reduced cultivation may provide cheaper and faster crop establishment, but in the past has been subject to problems with (poor crop establishment) weeds and soil compaction. With modern cultivation and sowing technology and methodology it may be possible to overcome these difficulties. In addition reduced cultivation is considered to be more environmentally friendly and sustainable than the conventional plough-based system. With these considerations in mind it was decided to start an experiment in autumn 2000 to compare the conventional system (PL) with reduced cultivation (RC) for crop establishment, and to examine the effect of incorporating the straw into then soil or baling and removing it. The treatments were assessed on winter wheat, and winter and spring barley. The parameters assessed included – crop establishment, yield and quality effects on disease levels, invertebrate pests and beneficials (aphids, slugs, earthworms, beetles), and soil conditions. The work reported here was conducted on four trial sites at Oak Park, Carlow and Knockbeg, Co. Laois from 2000 to 2003. the objectives were to establish the efficacy of RC compared with PL and to its effects on the parameters outlined above. Plant establishment was lower after RC in most of the experiments. Winter wheat yields were good irrespective of the number of plants established and there were no significant differences between cultivation or straw disposal method. The relative yields of the PL and RC treatments in winter barley varied over the three years; in 2001 there was no difference, in 2002 PL yielded 1 t/ha more than RC, while in 2003 the PL area produced 2 t/ha extra. Spring barley yields were similar on the PL and RC treatments. Broadleaved weeds were not a problem on the PL or RC treatments but there were more annual grass weeds on the RC plots. This was particularly serious in the winter barley experiments where sterile brome (Bromus sterilis) had a big effect on yield by 2003. annual meadow grass (Poa annua) was a problem in both PL and RC areas if not controlled by timely herbicide application; this was particularly so on the headland areas in the spring barley field. Disease assessment on the winter wheat trail showed no significant differences in Take-all or Eyespot levels between cultivation or straw disposal methods, although Take-all levels tended to be lower on the RC plots. Soil strength as measured by cone penetrometer and shear vane was higher on the RC treatments. In the winter wheat there was no difference in slug numbers between any of the treatments. Leaf damage by slugs increased in RC relative to PL but not significantly, in 2003. No below ground slug damage was found. Earthworm numbers in the winter barley increased significantly on the RC treatment relative to the PL as the study progressed. Straw incorporation increased earthworm numbers on both PL and RC treatments. Allolobophora chlorotia was the most common species in 2004. In the winter wheat the RC and straw incorporation increased earthworm numbers. Cultivation method had a greater effect on ground beetle numbers than method of straw disposal. Large species (e.g. Pterostichies malanarius) were favoured by RC while smaller species (e.g. Bembidon species) were more numerous in the PL plots. Molecular studies on virus diseases, vectors and vector-predators are underway in progress. In the invertebrate pests and beneficials investigations the RC winter barley had 11% fewer aphids and 27% less BYDV than the PL. Incorporating straw reduced aphid numbers and virus incidence by 36% and 32% respectively; the comparable values for the PL + straw treatment were 15% and 15%. In the winter wheat there was less BYDV in the RC plots than the PL + less were the straw was incorporated than where the straw was removed. Aphid infestation of wheat ears was low in the three years of the experiment. The insecticide seed treatment imidacloprid significantly reduced aphid numbers and virus incidence in winter barley but was less effective than a single insecticide spray in controlling the disease. The seed treatment was more effective in controlling BYDV in RC than in the PL plots. Estimations of slug numbers in the winter barley showed that the dominant species was the grey field slug (Deroceras reticulatum). Slug numbers increased significantly on all treatments between 2001 and 2004. In November 2004, slugs were significantly more numerous in the RC treatments than in the PL areas. Leaf damage was proportional to slug populations, but the slugs did not damage the barely seed or reduce plant populations in continuous winter barley under RC. Root and stem diseases (Take-all and Eyespot) were not nay worse under RC than after PL. In fact there was a tendency towards lower disease levels on the RC areas and there was significantly less sharp eyespot on the RC treatment