Injecting Bio Solids into Grass and Arable Crops, Part II: Development of a Shallow Application Technique     

D. W. M. Pullen  R. J. Godwin  P. Grundon  M. J. Hann 《Biosystems Engineering》2004,87(4):393-406

Digested sludge contains valuable crop nutrients but these are largely lost because current application techniques limit where and when it can be applied. Soil injection to depths in excess of 150 mm to reduce odour problems can only be used on fallow land or grass because of the damage it can cause. This leads to applications at high rates being applied with increased environmental risk. The aim of this study was to determine the benefits and limitations of injecting digested sewage sludge into land growing arable crops using shallow, less than 100 mm deep, injection techniques. Agronomic trials conducted over 2 years with winter wheat and rape showed that the crops were surprisingly resistant to mechanical damage during the growing season. Crop yields were not effected by injecting sludge into the crop up to March, equivalent to growth stage 30 in winter wheat, using a conventional tractor-based system working. Injection is possible later in the growing season based on systems with the tractor operating along “tramlines” for field traffic control.  相似文献   

An Economic Analysis of the Potential for Precision Farming in UK Cereal Production   总被引：1，自引：0，他引：1  

R. J. Godwin  T. E. Richards  G. A. Wood  J. P. Welsh  S. M. Knight 《Biosystems Engineering》2003,84(4):533-545

The results from alternative spatial nitrogen application studies are analysed in economic terms and compared to the costs of precision farming hardware, software and other services for cereal crops in the UK. At current prices, the benefits of variable rate application of nitrogen exceed the returns from a uniform application by an average of £22 ha⁻¹ The cost of the precision farming systems range from £5 to £18 ha⁻¹ depending upon the system chosen for an area of 250 ha. The benefits outweigh the associated costs for cereal farms in excess of 80 ha for the lowest price system to 200–300 ha for the more sophisticated systems. The scale of benefits obtained depends upon the magnitude of the response to the treatment and the proportion of the field that will respond. To be cost effective, a farmed area of 250 ha of cereals, where 30% of the area will respond to variable treatment, requires an increase in crop yield in the responsive areas of between 0·25 and 1.00 t ha⁻¹ (at £65 t⁻¹) for the basic and most expensive precision farming systems, respectively.  相似文献   

Developing Strategies for Spatially Variable Nitrogen Application in Cereals, Part II: Wheat     

J. P. Welsh  G. A. Wood  R. J. Godwin  J. C. Taylor  R. Earl  S. Blackmore  S. M. Knight 《Biosystems Engineering》2003,84(4):495-511

For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of wheat (Triticum aestivum) over three seasons in two fields. The aim was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate in the field with three different soil series (predominantly calcareous silty clay loam over oolitic limestone) was uniform across the field. In contrast the other field with uniform soil type (slightly calcareous brown clay loam), provided a more variable response. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, which is currently the most practical commercial system, based on 3 yr of yield data, were variable with no overall yield or economic advantages. It was concluded that that this approach may not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that there was insufficient variation in the shoot density in the field with diverse soil types. However, in the field with the uniform soil type, applying additional N to areas with a low shoot population and maintaining the standard N rate to areas with an average shoot population resulted in an average strategy benefit of up to 0·46 t ha⁻¹ compared with standard farm practice. It is necessary to combine the ‘real-time’ data on relative crop structure, obtained by remote sensing with ground truth assessments and absolute benchmark values to successfully adjust N input levels to maximise yield.  相似文献   

Soil Factors and their Influence on Within-field Crop Variability, Part II: Spatial Analysis and Determination of Management Zones     

J. C. Taylor  G. A. Wood  R. Earl  R. J. Godwin 《Biosystems Engineering》2003,84(4):441-453

Spatial variation of crop yields was examined in three trial cereal fields in England from 1994 through 1997. The fields were managed with uniform inputs but there were considerable differences in the spatial patterns and magnitudes of variation between fields and seasons. Up to 50% of the yield variation was within the tramline spacing distance (20–24 m) and this appeared to relate to crop management practices rather than underlying soil factors. Longer-range variation generally increased up to field scale but was not constant between seasons. Longer-range variation was more apparent in dry years and was attributable to soil variation. Soil series differences coincided with yield differences in dry years when the soil series differences could be expected to create large differences in soil–water relationships. Soil electrical conductivity, measured by electromagnetic induction (EMI), was investigated as a surrogate for detailed soil coring. Field zones created by EMI also coincided with yield differences and zones were similar to those delineated by soil series with expected differences in soil–water relationships. The EMI observations were found to be a useful and cost-effective surrogate for representing soil variability in fields likely to create yield variations. Subdivision of fields into management zones using multi-variate K-means cluster analysis of historical yield and EMI observations formed an objective basis for targeting soil samples for nutrient analysis and development of site-specific application strategies. The appropriateness of site-specific management has to be assessed annually because magnitude and pattern of variation changes from season to season.  相似文献   

The Analysis of Spatial and Temporal Trends in Yield Map Data over Six Years   总被引：1，自引：0，他引：1  

Simon Blackmore  Richard J. Godwin  Spyros Fountas 《Biosystems Engineering》2003,84(4):455

A quantitative analysis of yield data from four fields over 6 years was carried out to identify the spatial and temporal trends. The methodology was modified from previous work to separate the temporal effects into two parts; the inter-year offset and the temporal variance. The inter-year offset quantifies the overall differences in yield between 1 year and the next, whereas the temporal variance indicates the amount of change at a particular point over time. Results from these fields show that the significant spatial variability found within each individual yield map cancelled out over time, leaving a relatively homogenous spatial trend map. The implications of these findings are that each field should be managed according to the current years’ conditions.  相似文献   

Influence of dietary arginine and glycine content on thyroid function and growth of juvenile rainbow trout, Oncorhynchus mykiss (Walbaum)     

W. W. RILEY  JR  D.A. HIGGS  B.S. DOSANJH  J.G. EALES 《Aquaculture Nutrition》1996,2(4):235-242

Juvenile rainbow trout, held at 12°C on a 12 h light :12 h dark photocycle, were fed a constant ration (1 % of body wt day ^?1) of isonitrogenous and isoenergetic diets that varied in either arginine content (3.6-56.1 g kg^?1 dry matter; experiment 1), or glycine (3.3–118 g kg^?1 dry matter) and alanine (5.0-42.3 g kg^?1 dry matter) content (experiment 2). In experiment 1, the lowest dietary level of arginine depressed growth, feed efficiency, plasma l -thyroxine (T₄) and 3,5,3′-triiodo-l -thyronine (T₃) levels and hepatic T₄ 5’monodeiodinase (5'D) activity responsible for T₄-to-T₃ conversion. Over the dietary range of 7.1–56.1 g arginine kg^?1, there was no change in 5'D activity, despite an arginine stimulation of growth. The optimum level of arginine for growth was within the range of 14.1–28.1 g kg^?1 of the diet or 32–63 g kg^?1 of dietary protein. In experiment 2, an increase in dietary glycine level, at the expense of glutamic acid, increased 5'D activity without attendant elevation of the plasma T₃ level. The latter finding suggests that glycine also induced a compensatory increase in T₃ degradation rate. This may explain why the glycine-induced increase in 5'D activity was unaccompanied by any changes in growth indices. Alteration of dietary alanine content did not affect growth or thyroid function. We conclude that of the various dietary amino acids tested, only glycine led to a progressive stimulation of hepatic T₄ 5'D activity. However, because glycine likely enhanced T₃ degradation, no increases in plasma T₃ or growth indices were found. Glycine may serve as an advance signal that activates thyroid function immediately preceding or coincident with energy and nutrient (especially protein) intake. This, in turn, may improve the efficiency of nutrient absorption and/or post-absorptive anabolic events.  相似文献   

Action of selected antibiotics on four common bacteria associated with diseases of fish     

K. E. NUSBAUM  E. B. SHOTTS  JR 《Journal of fish diseases》1981,4(5):397-404

Abstract. Four bacteria commonly associated with diseases of fish ( Aeromonas hydrophila complex, Aeromonas salmonicida, Flexibacter columnaris -like organisms and Pseudomonas fluorescens ) were evaluated in a serial dilution system for susceptibility to four antibiotics commonly used in the treatment of bacterial fish diseases (chloramphenicol, erythromycin, furpyrinol and oxytetracycline). Findings were expressed as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Furpyrinol was found to have the lowest MIC and MBC against A. hydrophila complex, A. salmonicida and F. columnaris-like organisms. MIC and MBC's for oxytetracycline were complicated by the presenceof R-plasmids, but were less than 4.0 mcg/ml for those without plasmids. Pseudomonas fluorescens was susceptible only to oxytetracycline. MIC for all groups of organisms using chloramphenicol was generally less than 16.0 mcg/ml. Susceptibility to erythromycin by these groups of organisms was greater than 16 mcg/ml.  相似文献   

Comparative sensitivity of five fish cell lines to wild type infectious haematopoietic necrosis virus from two Oregon sources     

J. L. FENDRICK  W. J. GROBERG  JR  J. C. LEONG 《Journal of fish diseases》1982,5(2):87-95

Abstract. Five fish cell lines (CHSE-214, STE-137, RTG-2, EPC and FHM) were compared for sensitivity to infectious haematopoietic necrosis virus (IHNV) from samples obtained from naturally-infected fish. Infectious ovarian fluids were obtained from steelhead trout, Salmo gairdneri Richardson, at the Round Butte Hatchery in central Oregon and tissue homogenates were prepared from chinook salmon, Oncorhynchus tshawytscha (Walbaum), alevins during an IHN virus epizootic at the Elk River Hatchery in coastal Oregon. The only lines to show characteristic viral cytopathology by plaque or end-point dilution assay for the steelhead trout virus isolate were the EPC and FHM cell lines. The chinook salmon isolates produced CPE in CHSE-214, STE-137, FHM and EPC cells. The titre of the salmon virus isolate was 10-50-fold higher on FHM and EPC cells by both assay methods. Neither by end-point nor plaque assay did the Round Butte or Elk River isolates produce CPE on RTG-2 cells. With both virus isolants both cell lines showed that greater sensitivity was obtained with plaque assay than with end-point titration. Pre-treatment of the cells with the polycation, polybrene, did not increase the virus titre in either assay. However, a transient enhancement in virus titre was observed in polybrene-treated STE-137 and CHSE-214 cells.  相似文献   

Haematological studies on frizzled and naked neck genotypes of Nigerian native chickens     

Peters SO  Gunn HH  Imumorin IG  Agaviezor BO  Ikeobi CO 《Tropical animal health and production》2011,43(3):631-638

Variation in haematological parameters of Nigerian native chickens was studied using 60 clinically normal frizzle-feathered, naked-neck, and normal-feathered native chickens. These included red blood cell count, haemoglobin, packed cell volume, white blood cell count, mean corpuscular volume, mean corpuscular haemoglobin concentration, serum glucose, urea, cholesterol, albumin, globulin and creatinine. Normal-feathered birds had higher (p < 0.05) mean values compared to frizzled and native neck genotypes except for albumin, red blood and white blood cells, and mean cell haemoglobin concentration. Males generally had higher mean values than their female counterparts across all genotypes. Correlation coefficients among the parameters were significant (p < 0.001) with r values ranging from 0.26 between red blood cell and mean corpuscular haemoglobin to 0.92 between red blood cell and cholesterol. Sufficient genetic variation therefore exists for haematological parameters among Nigerian native chickens that may represent indicator traits for further study. However, the application of molecular tools will provide better understanding and application of these differences.  相似文献   

Resection and anastomosis of the small colon in four horses     

AJ DART  JR SNYDER  JR PASCOE 《Australian veterinary journal》1992,69(1):5-7

Resection and anastomosis of the small colon was performed on 4 horses with vascular lesions (strangulating lipoma, mesenteric tear, dissecting haematoma) or functional obstruction (stricture) of this area of the bowel. The anastomoses were performed using a variety of suture materials in 2 layers. An appositional, full-thickness, simple, interrupted pattern was used in the first layer in all cases and oversewn with either a Cushing pattern (3 cases) or a Utrecht pattern (1 case). Post-operative complications associated with suture material and surgical technique were not seen. All horses were discharged from the hospital and all were alive more than one year after discharge.  相似文献