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1
Jacobs, J. L., F. R. McKenzie, and G. A. Kearney. "Nitrogen fertiliser effects on nutritive characteristics of perennial ryegrass during late autumn, and mid- and late winter in western Victoria." Australian Journal of Experimental Agriculture 42, no. 5 (2002): 541. http://dx.doi.org/10.1071/ea01144.
Full textAbstract:
A study determined the effects of differing rates of nitrogen fertiliser [0 (N0), 25 (N1), 50 (N2) and 75�kg N/ha (N3)] during late autumn (T1) and mid- (T2) and late (T3) winter on the nutritive characteristics of perennial ryegrass over a 28-day period after each application. All nitrogen applications were made to pastures with a post-grazed residual mass (dry matter) of 1400 kg/ha. Changes in metabolisable energy followed similar patterns for all treatments within a given period. Metabolisable energy was highest in T1, ranging from 11.8 to 13.1 MJ/kg dry matter, followed by T2 (11.5-12.3 MJ/kg dry matter) and T3 (10.6-11.5 MJ/kg dry matter). Changes in crude protein for all treatments at each application time were similar, irrespective of rate of nitrogen application. At the commencement of treatment application times, the existing crude protein content (%DM) was highest in N3 (T1�19, T2 23, T3 22), followed by N2 (T1 18, T2 21, T3 21), N1 (T1 17, T2 20, T3 20) and N0 (T1 16, T2 17, T3 18). During both T1 and T2, neutral detergent fibre content decreased by 4 percentage units and increased by a similar amount during T3. Generally, neutral detergent fibre content (%DM) was highest during T3 (53-58%), followed by T2 (45-54%) and T1 (43-49%). Water-soluble carbohydrate content (%DM) increased during all treatment periods with the highest level observed during T1 (18-31%) followed by T2 (3-14%) and T3 (1-6%). Nitrate content (measured as nitrate-nitrogen) decreased throughout T1, primarily due to dry conditions, while during T2, levels for N3 and N2 were significantly (P<0.05) higher than for N1 and N0 following nitrogen fertiliser application. During T3, nitrate content increased for all treatments throughout the 28-day period, with highest nitrate levels being observed during T3. The effect of applied nitrogen on mineral content was variable within and across treatment periods. The study indicates that nitrogen fertiliser did not affect metabolisable (apart from N3 elevating metabolisable energy during T3), neutral detergent fibre or water-soluble carbohydrate contents of perennial ryegrass during the 28 days after nitrogen application, but increased crude protein content. Also, nitrogen fertiliser elevated nitrate content in perennial ryegrass. While the elevated nitrate content observed may result in subclinical effects, these levels are not considered fatal for dairy cows. Crude protein content was generally above 20% of dry matter throughout the study and close to 30% of dry matter for short periods during T2. Minimising the effect of excess nitrogen ingested by the grazing animal may require appropriate supplementation of low crude protein containing feeds such as cereal grains. It is argued that the effects of rain and temperature, which impact on soil nitrogen mineralisation, may have a greater influence on perennial ryegrass nitrate content than nitrogen fertiliser.
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Jacobs, J. L., F. R. McKenzie, S. E. Rigby, and G. Kearney. "Effect of nitrogen fertiliser application and length of lock up on dairy pasture dry matter yield and quality for silage in south-western Victoria." Australian Journal of Experimental Agriculture 38, no. 3 (1998): 219. http://dx.doi.org/10.1071/ea97151.
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Summary. This study aimed to define the effect of differing rates of nitrogen application and lock up length on harvested material for silage in south-western Victoria. At 2 sites in south-western Victoria, 140, 3 by 2 m plots of predominantly perennial ryegrass pasture were randomly allocated, within 4 replicate blocks. Five nitrogen fertiliser rates (0, 25, 50, 75, 100 kg N/ha) in combination with 7 lock up lengths were randomly allocated to the 35 plots within each replicate. Nitrogen was applied 1 week after initial lock up (September 10, site 1; September 12, site 2) and harvesting commenced 3 weeks after initial lock up. For each treatment and harvest date, dry matter yield and botanical composition were determined and samples of total pasture and the ryegrass fraction were collected and chemically analysed for dry matter digestibility, crude protein, neutral detergent fibre, water-soluble carbohydrates and mineral content. Metabolisable energy was derived from dry matter digestibility. Increasing rates of nitrogen increased herbage dry matter yield regardless of length of lock up. The yield response was greatest 8 weeks after initial lock up at both sites (site 1, 26 kg DM/kg N; site 2, 14.9 kg DM/kg N). Subsequent regrowth of pasture was increased by nitrogen application over shorter lock up lengths (weeks 3 and 4). Botanical composition was unaffected by treatment during the harvesting period or in the subsequent autumn. Application of nitrogen gave rise to a linear increase in pasture metabolisable energy and crude protein content at both sites until week 5. Thereafter, this response diminished and by week 8 there was a decrease in metabolisable energy and crude protein content. Neutral detergent fibre content was relatively unaffected by nitrogen application until week 8 of the study, at which point there was a linear increase. Application of nitrogen reduced the water-soluble carbohydrate content of pastures throughout the sampling period. It is concluded that application of nitrogen to a mixed sward locked up for silage can increase dry matter yield and, provided pasture is harvested before ryegrass ear emergence, can also have a positive effect on metabolisable energy and crude protein. Given that the decision for removing paddocks from the grazing rotation is based upon pasture growth and stocking rates, the use of nitrogen fertilisers on higher stocked farms could lead to increased dry matter yield over shorter lock up periods. On farms with lower stocking rates shorter lock up periods may allow for pastures to be returned to the grazing rotation earlier, or provide the opportunity for a second harvest of pasture for silage.
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Incerti, M., and GJ O'Leary. "Rooting depth of wheat in the Victorian Mallee." Australian Journal of Experimental Agriculture 30, no. 6 (1990): 817. http://dx.doi.org/10.1071/ea9900817.
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In 1986 and 1987 wheat was sown in an experiment at the Mallee Research Station, Walpeup, at 2 times of sowing and with 3 rates of applied nitrogen. Soil cores were taken and trenches excavated to 1.5 m to measure wheat root growth and depth of rooting. Wheat roots penetrated to a maximum depth of 104 cm in crops sown in May, the optimum time of sowing for maximum yield, while delayed sowing reduced total root biomass and limited rooting depth to 73-83 cm. The application of nitrogen fertiliser did not affect either the rooting depth or growth and yield. Significant changes in total soil water content between sowing and harvest only occurred in 1987 with the early and late sown crops reducing the total soil water content by 47 and 99 mm respectively. In 1986, above average rainfall during the growing season caused the early sown crop to accumulate more water below 50 cm than the late sown crop. While total water use was increased only in 1986 with early sowing, crop water use efficiency and yield was greater in both years. The addition of nitrogen had no effect on crop water use or water use efficiency. A survey of wheat crops carried out in 1988 on 10 Mallee farms also found that shallow rooting is widespead. The field experiment and survey data show that, irrespective of sowing time, roots did not penetrate as far down the profile as might be expected, given reported rooting depths commonly in excess of 200 cm on similarly textured soils. This was shown to be associated with high soil pH and salt content. Poor rooting depth of wheat in this environment will restrict the use of stored water and accordingly, calls the practice of fallowing into question.
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Jacobs, J. L., G. N. Ward, and G. Kearney. "Effects of irrigation strategies and nitrogen fertiliser on turnip dry matter yield, water use efficiency, nutritive characteristics and mineral content in western Victoria." Australian Journal of Experimental Agriculture 44, no. 1 (2004): 13. http://dx.doi.org/10.1071/ea03054.
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The effect of different irrigation strategies on turnip forage crop growth rates, dry matter (DM) yield, water use efficiency (WUE), changes in soil volumetric water content, nutritive characteristics and mineral content was determined on different soil types at different sites (site 1 and 2) over 2 years. Treatments were: (A) a dryland control; (B) fully watered to soil field capacity each week; (C) 75% of full watering; (D) 50% of full watering; (E) 25% of full watering; (F) a single watering to soil field capacity or to a maximum of 50 mm between weeks 0–6; (G) a single watering between weeks 6–8; (H) a single watering between weeks 8–10; and (I) a single watering between weeks 10–12 after sowing. In addition, each irrigation treatment received either 0 or 50 kg N/ha applied 5 weeks after sowing. Responses to applied irrigation water were different at each site and also within one year. At site 1, responses to irrigation were adversely affected by insect damage and delayed sowing, particularly in year 1. However, there were significant increases in DM yield to weekly irrigation regimes in both years, with responses greater in year 2, and responses in both years were greater where nitrogen was applied. At site 2, there were significant responses to weekly irrigation regimes in year 1 with DM yields from fully irrigated plots almost double that of the dryland treatment. In year 2, DM yields from all treatments were similar and it is proposed that lower summer temperatures may have contributed to the improved DM yield observed with the dryland treatment. In both years, at site 2, there were generally higher DM yields with nitrogen application irrespective of irrigation regime. Turnip metabolisable energy values were consistently above 11.5 and 13 MJ/kg DM for leaves and roots respectively, with crude protein contents for leaves ranging from 11 to 20% and 13 to 24% and roots from 6 to 14% and 9 to 17% at sites 1 and 2, respectively. Water use efficiencies varied according to irrigation treatment with higher efficiencies observed at site 2 in both years. In year 1 and 2, total WUE at site 1 varied from 5 to 11 kg DM/ha.mm while at site 2 the range was 20–48�kg�DM/ha.mm with higher values being observed in year 2. As with DM yields it is likely that the observed higher WUE in year 2 was due to lower summer temperatures. At site 2, the dryland treatments produced the highest efficiencies in both years. In contrast, WUE from applied irrigation water ranged from 0 to 35 kg DM/ha.mm at site�1 and from 0 to 23 kg DM/ha.mm at site 2. This study suggests that there is potential to economically irrigate turnips to provide additional DM of high nutritional value for lactating dairy cows, however, issues such as sowing dates, soil type, and insect damage will also influence final yields. In particular, summer temperatures influence both dryland growth potential and growth responses to irrigation. Also single irrigations during the growing period will not significantly increase DM yields over a crop grown under dryland conditions.
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Jacobs, J. L., G. N. Ward, A. M. McDowell, and G. A. Kearney. "A survey on the effect of establishment techniques, crop management, moisture availability and soil type on turnip dry matter yields and nutritive characteristics in western Victoria." Australian Journal of Experimental Agriculture 41, no. 6 (2001): 743. http://dx.doi.org/10.1071/ea01009.
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Factors associated with turnip dry matter yield, metabolisable energy and crude protein were investigated in 266 turnip forage crops on 142 dairy farms in south-western Victoria during spring 1999 and summer 2000. Factors measured were primary cultivation method, secondary cultivation method, soil texture, soil temperature and moisture at sowing, seedbed preparation, turnip variety, sowing method, sowing rate, rolling post-sowing, harrowing post-sowing, seedling establishment, insect damage, water received, phosphorus and nitrogen application. The average date for the commencement of seedbed preparation was early October, although the range was from mid-March until mid-December. Sowing dates ranged from mid-September to mid-December, with an average of mid-October. The most common turnip variety sown was Barkant, followed by Mammoth Purple Top, Vollenda and Rondo. Growing periods ranged from 8 to 23 weeks, with the majority of crops grazed from 8 to 15 weeks. The average dry matter yield was about 5 t DM/ha, with values ranging from 0.4 to 19.2 t DM/ha. The average metabolisable energy content of turnips was 13.7 MJ/kg DM with values ranging from 11.3 to 14.6 MJ/kg DM. The metabolisable energy of roots was on average higher than the leaf component of the plants (14 v. 13.5 MJ/kg DM). Conversely, crude protein content of leaves (15.4%) was higher than in the root fraction (13.9%). The average neutral detergent fibre content of turnips was 22.5% with values ranging from 16.9 to 30.5%. The water-soluble carbohydrate content of the leaf component ranged from 1.1 to 26.8% with an average of 14.7%, while starch content of the root component ranged from 0.3 to 38.8% with an average content of 16.9%. The average cost of growing a turnip crop was $485/ha or $133 t DM. Total, leaf and root dry matter yield as well as metabolisable energy and crude protein were analysed by a mixed effects model (with factors fixed and farms and paddocks random). Factors that were associated with total dry matter yield were total water received, soil temperature and moisture at sowing, seedling density, method of secondary cultivation, soil type and insect damage. The application of nitrogen fertiliser had the greatest association with turnip crude protein content. In conclusion the findings of this study indicate potential ways to increase the dry matter yield of turnips grown in south-western Victoria. Given the current average dry matter yields and cost of growing turnips, purchasing cereal grain may be a viable alternative. An increase in average dry matter yield would make the choice of growing turnips as a feed for lactating dairy cows a more profitable option.
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Jacobs, J. L., G. N. Ward, F. R. McKenzie, and G. Kearney. "Irrigation and nitrogen fertiliser effects on dry matter yield, water use efficiency and nutritive characteristics of summer forage crops in south-west Victoria." Australian Journal of Experimental Agriculture 46, no. 9 (2006): 1139. http://dx.doi.org/10.1071/ea05122.
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Summer forage crops form an integral component of feed rations to meet the dietary requirements of dairy cows in south-west Victoria. Irrigation of such crops has the potential to increase the availability of feed of high nutritive value. The effect of irrigation strategies and nitrogen (N) fertiliser on forage crop accumulation rates, dry matter yield, water use efficiency and nutritive characteristics was determined at each harvest over 2 summers. The crops used were Hunter (Brassica campestris L. × Brassica napus L.), Graza (a complex hybrid of Raphanus sativus L. with introgression from Raphanus maritimus L. and Brassica oleracea L.) and Shirohie millet (Echinochloa utilis Ohwi & Yabuno). Irrigation treatments were dryland control, weekly irrigation to 100% of estimated requirements, weekly irrigation to 50% of estimated requirements and 25% of estimated requirements every second week. Following sowing and after each harvest, N was applied at either 50 or 100 kg N/ha (brassica crops, 3 applications; millet, 2 applications). In both years, fully irrigated crops produced higher dry matter yields than the dryland crops for all species. For Hunter and Graza, full irrigation also resulted in higher dry matter yields than irrigating every second week. Nitrogen at the higher application rate led to higher dry matter yields for Graza in both years and for millet in year 1. Irrigation had inconsistent effects on the nutritive characteristics of all species. Metabolisable energy content ranged from 10.1 to 13.6, 9.8 to 13.3 and 8.2 to 11.3 MJ/kg dry matter for Hunter, Graza and millet, respectively. Nitrogen application at 100 kg N/ha resulted in higher crude protein content for Hunter and Graza at the second and third harvests and for millet at the second harvest at 50 kg N/ha in both years. Water use efficiencies (irrigation plus effective rainfall) varied according to species with all dryland crops having higher water use efficiencies than the irrigated crops. Total water use efficiencies ranged from 21 to 55, 17 to 39 and 28 to 86 kg dry matter/ha.mm for Hunter, Graza and millet, respectively. In contrast, water use efficiencies from applied irrigation water ranged from 0 to 18 kg dry matter/ha.mm for Hunter, 5 to 18 kg dry matter/ha.mm for Graza and 3 to 33 kg dry matter/ha.mm for millet. Economic assessments indicated average costs for dryland Hunter, Graza and millet to be AU$94, $124 and $76/t dry matter and average costs for fully irrigated crops to be $57, $67 and $51/t dry matter, respectively. This study indicates there is potential to economically irrigate these species to provide additional dry matter of medium to high nutritional value to feed lactating dairy cows through late spring and summer. The data also indicate that for the irrigation of summer forage crops in this environment, the most efficient use of limited water supplies is likely to be a weekly application of water at 50% of the estimated perennial pasture requirements.
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Cain, S., and PI Boon. "Cellular osmotica of plants in relation to sediment nitrogen and salt content in mangroves and saltmarshes at Western Port, Victoria." Marine and Freshwater Research 38, no. 6 (1987): 783. http://dx.doi.org/10.1071/mf9870783.
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Sediments from mangrove and saltmarsh areas at Yaringa, Western Port contained high concentrations of chloride (c. 330-2100 mmol per litre of interstitial water) and sodium (c. 320-1900 mmol 1-1). The concentrations recorded during the study were highest in March and lowest in July-August; salinity in the marsh during summer was considerably higher than that commonly reported for saltmarshes in other parts of the world. Sediment ammonium contents (c. 180-580 nmol per cm3 of fresh sediment) were variable across the marsh and throughout the sampling period, with there being little overall pattern to these changes. In contrast, concentrations of nitrate plus nitrite were low (< 100 nmol cm3) for most of the year except for a period in March when they were extremely high (c. 1100-1800 nmol cm-3). The leaf-cell sap of all saltmarsh and mangrove plants contained high concentrations of chloride (c. 300-1200 mmol per litre of cell sap), sodium (c. 280-900 mmol l-1) and potassium (c. 40-200 mmol l-1). Glycinebetaine was accumulated in the leaf-cell sap to concentrations of up to about 90 mmol l-1 by Atriplex paludosa, Avicennia marina, Sarcocornia quinqueflora, Sclerostegia arbuscula and Suaeda australis. Proline and glycinebetaine were accumulated by Limonium australe, Samolus repens, Selliera radicans and Triglochin striata, but no species accumulated proline alone. Concentrations of inorganic osmotica in the foliage were generally highest in March, whereas glycinebetaine and proline were at their most concentrated in April. No significant relationship was detected between concentrations of organic osmotica in the plants and that of salt or inorganic nitrogen in the sediments.
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McKenzie, F. R., J. L. Jacobs, and G. Kearney. "Long-term effects of multiple applications of nitrogen fertiliser on grazed dryland perennial ryegrass/white clover dairy pastures in south-west Victoria. 3. Botanical composition, nutritive characteristics, mineral content, and nutrient selection." Australian Journal of Agricultural Research 54, no. 5 (2003): 477. http://dx.doi.org/10.1071/ar02189.
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A grazing experiment was undertaken on a commercial dairy farm in south-west Victoria over a 3-year period to study the effects of multiple applications of different rates of nitrogen (N) fertiliser over autumn and winter on dairy pasture species composition, nutrient characteristics, mineral content, and nutrient selection. Four treatments, replicated 3 times in a randomised block design, comprised: zero N (A); 3 applications of 25 kg N/ha (B); 3 applications of 50 kg N/ha (C); and 3 applications of 75 kg N/ha (D).Increasing rates of N fertiliser generally elevated whole sward metabolisable energy (ME) content. The effect of N fertiliser on whole sward ME content was evident through to the end of sampling each year (2–3 months after the last N application). Increasing rates of N fertiliser consistently elevated whole sward crude protein (CP) content. The effect of N fertiliser on whole sward CP content was evident through to the end of sampling each year (2–3 months after the last N application). For each year there was a slight decrease in CP, with Treatments C and D decreasing at a greater rate than treatments A and B. Increasing rates of N fertiliser generally depressed whole sward neutral detergent fibre (NDF) content. The effect of N fertiliser on whole sward NDF content was evident through to the end of sampling each year (2–3 months after the last N application). For each year there was a slight increase in NDF, with Treatments C and D having a lower increase in NDF over time than Treatment A. Nitrogen fertiliser had no effect on whole sward water soluble carbohydrate content.There was no consistent effect of N fertiliser on whole sward pasture mineral content during the growth season (June–December), with mean annual levels of P, K, S, Na, Ca, and Mg satisfying the nutritional requirements of high producing dairy cows and the growth requirements of both perennial ryegrass and white clover.Although N fertiliser had no influence on the concentration of nutrients consumed by grazing dairy cows, the mean annual range in selection differentials for the 3 years for ME (1.06–1.11) and CP (1.18–1.32) concentrations consumed was higher and the NDF (0.85–0.91) lower than those of the pasture.Each year there was an increase in perennial ryegrass, with Treatments B and C having a higher overall ryegrass presence compared with Treatment A. Nitrogen fertiliser had no effect on white clover, other grasses, weeds, or dead fractions.
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Sadras, Víctor, David Roget, and Garry O'Leary. "On-farm assessment of environmental and management constraints to wheat yield and efficiency in the use of rainfall in the Mallee." Australian Journal of Agricultural Research 53, no. 5 (2002): 587. http://dx.doi.org/10.1071/ar01150.
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The responses of wheat grain yield to soil properties, weather, root diseases, and management practices were investigated in 75 grower-managed crops in the Mallee region of South Australia, Victoria, and New South Wales during 3 growing seasons. Fourteen cultivars were represented in the sampled crops, with Frame being the most common (56%). The most widespread crop sequence was wheat after pasture (43% of wheat crops), followed by wheat after fallow or cereal (both about 20%); 12% of the wheat was sown after legumes. Wheat after cereal was more common in drier sites, and wheat after fallow in wetter sites. Wheat yield was proportional to Fischer’s photothermal coefficient around flowering, and ranged from nil to 4.7 t/ha. On average, wheat crops sown after cereals yielded 0.4 t/ha less than their counterparts sown after fallow, and 0.7 t/ha less than those after legumes. Sowing date ranged from 24 April to 21 July; yield declined with delayed sowing at an average rate of 17 kg/ha.day. Growing season rainfall (April–October) ranged from 111 to 266 mm, and accounted for 27% of the variation in grain yield. Soil water content at sowing (0–1 m) ranged from 32 to 330 mm; yield increased with initial soil water at an average rate of 6 kg/ha.mm. Grain yield per unit growing season rainfall was generally low, with 75% of crops producing <12 kg grain/ha.mm; the maximum ratio was 21 kg/ha.mm. Soil constraints, including sodicity, alkalinity, salinity, and boron toxicity, reduced yield in part by reducing availability of stored soil water. Owing to severity of chemical constraints increasing with soil depth, grain yield and yield per unit growing season rainfall were both inversely related to the proportion of water stored deeper in the soil (0.5–1 m). Yield was unrelated to nitrogen, both initial and applied. Larger amounts of nitrogen accumulated in soils with more severe constraints partially accounted for the lack of association between yield and nitrogen.
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Jacobs, J. L., F. R. McKenzie, M. J. Ryan, and G. Kearney. "Effect of rate and time of nitrogen application from autumn to midwinter on perennial ryegrass - white clover dairy pastures in western Victoria. 2. Pasture nutritive value." Australian Journal of Agricultural Research 50, no. 6 (1999): 1067. http://dx.doi.org/10.1071/ar98197.
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Field experiments were carried out at 2 sites to study the effects of time and rate of nitrogen (N) application from autumn to midwinter on the nutritive value of perennial ryegrass–white clover dairy pastures in western Victoria. Nitrogen (0, 15, 25, 30, 45, and 60 kg/ha) was applied in mid-April, early May, mid-May, early June, and mid-June during 1996 onto a pasture which had been grazed and topped to a uniform height of 5 cm prior to imposition of treatments. Pasture samples to a height of 5 cm were collected when perennial ryegrass in the 45 kg N/ha treatment reached the 3-leaf stage of development. Samples were analysed for metabolisable energy (ME), crude protein (CP), neutral detergent fibre (NDF), and water-soluble carbohydrates (WSC). Increasing rates of N gave rise to a curvilinear (Site 1) and linear (Site 2) increase in pasture ME and CP content. The actual response of 0.007 MJ/kg DM. kg N at 45 kg N/ha was the same at both sites, regardless of N application time, and corresponded to an increase of 0.32 MJ/kg DM. At Site 1 the actual increase in CP content at 45 kg N/ha (0.067% per kg N applied) was the same for all application times and corresponded to an increase in CP content of 3%. For Site 2, the increase ranged from 0.040% (mid-April) to 0.098% (mid-May) per kg N, corresponding to a pasture CP content increase of 1.8 to 4.4% at 45 kg N/ha, respectively. The application of N gave rise to a curvilinear (Site 1) and linear (Site 2) decrease in pasture NDF. For Site 1 at 45 kg N/ha, the actual decrease ranged from –0.04% (early May) to –0.10% (mid-May) per kg N, corresponding to a pasture NDF content decrease of 1.69 to 4.61%, respectively. At Site 2, the actual decrease in NDF content (–0.04% per kg N applied) was the same for all application times and corresponded to a decrease of 1.58% at 45 kg N/ha. Apart from some exceptions, increasing rates of applied N gave rise to a linear (Sites 1 and 2) decrease in pasture WSC content. For Site 1, the change in pasture WSC content ranged from 0.007% (early May) to –0.032% (mid-June application) per kg N, corresponding to a change in pasture WSC content of 0.32 to –1.44% at 45 kg N/ha, respectively. At Site 2, the change in WSC content ranged from 0.0004% (mid-April) to –0.076% (mid-May) per kg N, corresponding to a change in pasture WSC content of 0.02 to –3.42% at 45 kg N/ha, respectively. In this study, N application had a positive effect on the nutritive value of dairy pastures in the autumn to midwinter, in western Victoria. This is particularly important for the provision of quality feed during this period as the majority of dairy herds in the region are calving at this time. Thus, the provision of an increased quantity of higher quality feed may lead to a reduction in the requirement for purchased feeds.
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McCaskill, M. R., and J. W. D. Cayley. "Soil audit of a long-term phosphate experiment in south-western Victoria: total phosphorus, sulfur, nitrogen, and major cations." Australian Journal of Agricultural Research 51, no. 6 (2000): 737. http://dx.doi.org/10.1071/ar99091.
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A nutrient audit was conducted on a long-term grazed fertiliser experiment at Hamilton in south-western Victoria to determine the fate of applied phosphorus (P) and sulfur (S). Single superphosphate had been applied at rates averaging between 1 and 33 kg P/ha.year since the start of the experiment in 1977. Soil samples were taken in 1994 by coring to a depth of 80 cm, and analysed for total soil nutrient concentration. Most (80%) applied P was in the top 43 cm of the soil profile. A further 6.5% had been transferred to sheep camp areas and 6.5% had been exported as product. It was estimated that <0.4% of applied P left the site in surface water movement. Unaccounted P (6.6%) was probably in the soil, but could not be detected because of the relatively wide confidence margin for total soil P. Only 31% of applied S was detected in the top 43 cm, 3.6% had been transferred to sheep camps, and 4.9% exported in product. Unaccounted S (60%) had probably moved deeper into the soil where it could not be detected from background levels of total soil S. Bulk density in the 0–5-cm layer increased by 1% for each additional ewe per ha, but decreased by up to 0.4% for each kg/ha.year of P fertiliser. Soil nitrogen (N) accumulated at 46 kg N/ha.year at the highest P application rate.Differences in total potassium (K) between low and high fertility treatments indicated that 20 kg K/ha.year had moved out of the 5–19-cm soil layer of the high fertility treatment. This was attributed to competition for exchange sites from calcium (Ca) in the superphosphate. It was concluded that fertilisers with a higher P : S ratio and a lower Ca content than superphosphate are more appropriate for the basalt-derived duplex soils because they would reduce problems associated with displacement of K in the soil profile.
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Cooke, JW, GW Ford, RG Dumsday, and ST Willatt. "Effect of fallowing practices on the growth and yield of wheat in south-eastern Australia." Australian Journal of Experimental Agriculture 25, no. 3 (1985): 614. http://dx.doi.org/10.1071/ea9850614.
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The effects on crop establishment, crop development and the yield of wheat of two methods of fallow preparation, at each of three lengths of fallow were investigated over 5 years on red duplex and associated soils in north-central Victoria. The two methods of preparation were: scarifying, which involved the repeated use of a tined tillage implement; and herbicide application, which involved the repeated use of non-residual herbicides to control weeds during the fallow phase. The three lengths of fallow were winter, spring and autumn, which were approximately 10, 8 and 2 months respectively. Grain yield on the scarifier treatments was 0.26 t/ha greater (P<0.10) than on the herbicide treatments. Grain yield on winter fallow was 0.46 and 0.56 t/ha greater (Pt0.01) than on spring and autumn fallows, respectively. Crop yield was positively correlated (R2= 0.49) with soil nitrate determined at the time the crop was sown, but was independent of available soil water content determined at that time. Winter fallowing conserved 15 and 29 mm more water than did spring and autumn fallowing respectively, and mineralized 26 and 28 kg/ha more nitrogen than did spring and autumn fallows respectively. Crop establishment (No. of plants/m of row) on the herbicide treatment was 89% (P< 0.05) of that on the scarifier treatment, but this was not the reason for the reduced grain yield on the herbicide treatment. The lower yields were caused by depressed crop vigour (number of spikes/m of row) which in turn was largely a consequence of the inefficient uptake of nitrogen. The yield benefits of scarifying appear to reflect the importance of the initial two or three cultivations.
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Incerti, M., PWG Sale, and GJ O'Leary. "Cropping practices in the Victorian Mallee. 2. Effect of long fallows on the water economy and the yield of wheat." Australian Journal of Experimental Agriculture 33, no. 7 (1993): 885. http://dx.doi.org/10.1071/ea9930885.
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Two experiments were conducted at the Mallee Research Station, Walpeup, between 1985 and 1989 to determine whether increases in wheat yield that occur after long fallows result from improvements in the supply and use of additional soil water conserved during the fallow. Although long fallows increased the amount of water stored in the soil at sowing (average 22 mm) and the yield of wheat (0.26 to 1.37 t/ha) in the first experiment, the results suggest no causal relationship between these increases. Improvements in wheat yield were attributed to increases in soil nitrogen availability and to control of cereal root diseases rather than to any increase in soil water conservation. This was confirmed in the second experiment, which was managed to ensure that nitrogen supply and cereal root diseases were not limiting crop production. Increases in soil water content at sowing resulting from long fallows did not result in higher wheat yields. This study suggests that long fallows cannot be justified on the basis of this increased soil water storage, as much of the additional soil water accumulated during the fallow period is stored in the lower part of the rootzone. Movement of this water below the rootzone during the growing season appears to be the main reason for the additional water stored at sowing, with long fallows failing to increase wheat growth and yield.
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Harris, R. H., M. C. Crawford, W. D. Bellotti, M. B. Peoples, and S. Norng. "Companion crop performance in relation to annual biomass production, resource supply, and subsoil drying." Australian Journal of Agricultural Research 59, no. 1 (2008): 1. http://dx.doi.org/10.1071/ar07135.
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A field experiment located in NE Victoria compared the productivity of cereals sown into mature lucerne (companion crop) with cereals and lucerne grown as monocultures. Additional nitrogen (N) and water was applied to investigate if increased resource supply could alleviate competition and improve cereal performance in the presence of lucerne. Cereal plant populations, lucerne and cereal biomass, and cereal grain yields and protein were measured throughout the experiment. Soil water content was also monitored over time to determine whether companion cropping compromised the ability of lucerne to extract deep soil water. While companion cropping depressed both lucerne and cereal production, the combined annual biomass production was greater than cereal and lucerne when grown alone. Averaged over the three seasons, companion cropping resulted in a 31% increase (P < 0.05) in total annual biomass compared with the lucerne monoculture, and an 18% increase compared with the cereal monoculture in the 2004–05 and 2005–06 seasons. Cereals growing with lucerne produced fewer tillers, spikes and consequently cereal biomass compared with cereals growing as a monoculture. Therefore, companion crops yielded 25% less (P < 0.05) grain compared with the cereal monoculture over the 3-year study. Competition for N and light in the pre-cereal stem elongation period, were likely causes. Increasing the supply of N and water did not result in a main treatment (monoculture v. companion crop) by additional resource interaction, indicating that cereal responses were the same irrespective of lucerne’s presence. The application of N, water and these combined inputs, resulted in a 13–40%, 35% and 49% increase (P < 0.05) in cereal grain yields, respectively. While companion cropping compromised lucerne’s capacity to extract water from deep soil layers to a degree, this practice was still able to maintain drier subsoil in comparison to the cereal monoculture.
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Colesie, Claudia, Maxime Gommeaux, T. G. Allan Green, and Burkhard Büdel. "Biological soil crusts in continental Antarctica: Garwood Valley, southern Victoria Land, and Diamond Hill, Darwin Mountains region." Antarctic Science 26, no. 2 (May 23, 2013): 115–23. http://dx.doi.org/10.1017/s0954102013000291.
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AbstractBiological soil crusts are associations of lichens, mosses, algae, cyanobacteria, microfungi and bacteria in different proportions forming a thin veneer within the top centimetres of soil surfaces. They occur in all biomes, but particularly in arid and semi-arid regions, even in the most extreme climates. They carry out crucial ecosystem functions, such as soil stabilization, influencing water and nutrient cycles, and contribute to the formation of microniches for heterotrophic life. In continental Antarctica especially, these roles are essential because no higher plants provide such ecosystem services. We provide a detailed description of biological soil crusts from Garwood Valley, McMurdo Dry Valleys region (78°S) and Diamond Hill (80°S) in the Darwin Mountains region. The coverage was low at 3.3% and 0.8% of the soil surface. At Garwood Valley the crusts were composed of green algal lichens, cyanobacteria, several species of green algae and the mossHennediella heimii(Hedw.) R.H. Zander. Diamond Hill crusts appear to be unique in not having any species of cyanobacteria. Major parts are embedded in the soil, and their thickness correlates with higher chlorophyll contents, higher soil organic carbon and nitrogen, which are fundamental components of this species poor cold desert zone.
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Kurmus, Halenur, Abbas Mohajerani, and Stephen Grist. "Polycyclic Aromatic Hydrocarbons (PAHs) in Fired Clay Bricks Incorporating Cigarette Butts." Materials 14, no. 8 (April 18, 2021): 2032. http://dx.doi.org/10.3390/ma14082032.
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Cigarette butts (CBs) are the most common littered waste in the world and may contain polycyclic aromatic hydrocarbons (PAHs) from the incomplete combustion of tobacco during burning. Therefore, to investigate the potential PAH residual remaining in fired clay bricks (FCBs) incorporating CBs and examine the environmental impact of utilizing toxic waste in the production of FCBs, a comprehensive PAH extraction analysis was conducted. The Soxhlet extraction method was utilized to conduct a qualitative and quantitative analysis of sixteen toxic Environmental Protection Authority (EPA) Polycyclic Aromatic Hydrocarbons (PAHs) in FCB samples incorporating CBs using gas chromatography–mass spectrometry (GC–MS). The concentrations of the mean total (Σ)PAHs for FCBs incorporating 0%, 0.5%, 1%, 1.5%, and 2% CBs by weight (wt) were found to be 0.183, 0.180, 0.242, 0.234, and 0.463 µg/mL. As expected, PAHs with higher water solubility and volatility, naphthalene, fluorene, anthracene, pyrene, fluoranthene, and chrysene were found at higher concentrations compared to lipophilic PAHs. The ΣPAH concentrations for all five FCB–CB mixes were well below the EPA Victoria solid waste hazard categorization threshold for industrial waste. Moreover, the samples were studied for their carbon content using the carbon, hydrogen, nitrogen, and sulfur (CHNS) analyzer and thermogravimetric analysis (TGA). The results confirm an almost 100% combustion process of CBs during the firing process. A content less than 0.3% suggests that all carbon within the FCB–CB mixture relatively disappeared during the firing process up to 1050 °C. However, further research regarding the emission of volatile organic compounds (VOCs) during the production of FCBs incorporating CBs should be conducted.
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Schefe, Cassandra R., Kirsten M. Barlow, Nathan J. Robinson, Douglas M. Crawford, Timothy I. McLaren, Ronald J. Smernik, George Croatto, Ronald D. Walsh, and Matt Kitching. "100 Years of superphosphate addition to pasture in an acid soil—current nutrient status and future management." Soil Research 53, no. 6 (2015): 662. http://dx.doi.org/10.1071/sr14241.
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Pasture-based animal production systems, which occupy a significant proportion of the landscape in Victoria, Australia, have historically been nutrient-limited, with phosphorus (P) often the most limiting nutrient. The Permanent Top-Dressed (PTD) pasture experiment was established in 1914 at the Rutherglen Research Station, Victoria, to investigate the management of this deficiency. The main objective of the PTD experiment was to demonstrate the value of adding P fertiliser at two rates to increase pasture productivity for lamb and wool production. We report on the status of the PTD soils after 100 years, investigating the long-term implications of continuous grazing and fertiliser management (0, 125 and 250 kg/ha of superphosphate every second year) of non-disturbed pasture. We investigated the long-term effects of P fertiliser on the forms and distribution of P and other relevant soil parameters. In the fertilised treatments, P has accumulated in the surface soils (0–10 cm) as both orthophosphate and organic P, with an Olsen P of 16–21 mg P/kg, which is non-limiting for pasture production. In the treatment with 250 kg superphosphate, there has also been movement of P down through the soil profile, probably due to the high sand content of the surface soil and the transfer through the profile of small quantities of water-soluble P and P bound to organic ligands. Over time, the site has continued to acidify (surface 0–10 cm); the soil acidity combined with aluminium (Al) concentrations in the fertilised treatments approach a level that should impact on production and where broadcast lime would be recommended. After 100 years of non-disturbed pasture, the surface soils of these systems would be in a state of quasi-equilibrium, in which the fertilised systems have high levels of carbon (C), nitrogen, P and exchangeable Al. The continued stability of this system is likely dependent upon maintaining the high C status, which is important to nutrient cycling and the prevention of Al phytotoxicity. There are two risks to this system: (i) the declining pH; and (ii) soil disturbance, which may disrupt the equilibrium of these soils and the bio-chemical processes that maintain it.
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Blaikie, SJ, FM Martin, WK Mason, and DJ Connor. "Effects of soil water supply and temperature on the photosynthesis of white clover and paspalum in irrigated pastures." Australian Journal of Experimental Agriculture 28, no. 3 (1988): 321. http://dx.doi.org/10.1071/ea9880321.
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Field canopy chambers were used to measure the effect of a range of soil water contents from surface ponding to very dry soil and the effect of high summer temperatures on the photosynthesis of irrigated white clover and paspalum pastures. Water was ponded for 5-12 days on swards of white clover and paspalum at full cover and on others that had been defoliated to a height of 50 mm. Photosynthetic rate was monitored each day and compared with a non-ponded control. In all cases there was little response in photosynthetic rate to ponding either with or without supplemental nitrogen fertiliser. Photosynthesis of full swards of white clover and paspalum was monitored during a drying cycle following irrigation and compared with the photosynthesis of a well-watered control. Soil water deficit was expressed in terms of cumulative evaporation minus rainfall (mm E - R) after irrigation. Water deficit stress reduced the maximum photosynthetic rate of white clover by 50% (from 0.8 mg CO2/m2.s at 25 mm E - R to 0.4 mg CO2/m2.s at 75 mm E - R), but the photosynthetic rate of paspalum did not decline until 70 mm E - R. At high irradiance, temperatures between 24 and 33�C had little effect on the photosynthetic rate of well-watered white clover, whereas the rate in paspalum was higher at temperatures between 29 and 38�C than at temperatures of 24-29�C. The slow surface drainage and subsequent rapid drying of the root-zone of flood irrigated soils, combined with the high temperatures experienced in northern Victoria during summer, favour paspalum and severely limit the productivity of white clover.
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Hirth, J. R., P. J. Haines, A. M. Ridley, and K. F. Wilson. "Lucerne in crop rotations on the Riverine Plains. 2. Biomass and grain yields, water use efficiency, soil nitrogen, and profitability." Australian Journal of Agricultural Research 52, no. 2 (2001): 279. http://dx.doi.org/10.1071/ar00006.
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In a field experiment in north-eastern Victoria (average annual rainfall 598 mm), the impact of 2–4 years of lucerne growth on the following 3–4 crops was assessed. Controls of continuous lucerne, annual pasture, and continuous crop were compared with 5 lucerne–crop rotations. Above-ground biomass and water use efficiency of lucerne, annual pasture, and crops were assessed, as were the soil N status, grain yields, and profitability of crops after lucerne. Lucerne grew more slowly over the autumn–spring growing season (20 kg DM/ha.day) than did annual pastures and crops (41 and 58 kg DM/ha.day, respectively), while over the spring–autumn period, it grew at a mean 26 kg DM/ha.day. The summer growth rates of lucerne were, however, highly variable (1–52 kg DM/ha.day). Despite large changes in temperature and water availability over the year, the biomass water use efficiency (WUEB) of lucerne was similar over the winter and summer growth seasons (16 and 10 kg DM/ha.mm, respectively) and averaged 13 kg DM/ha.mm for the whole year. In contrast, the WUEB of wheat, canola, and annual pasture over their respective growth seasons averaged 36, 38, and 26 kg DM/ha.mm. When calculated over a whole year, however, they were much closer to lucerne at 23, 14, and 17 kg DM/ha.mm, respectively. Autumn removal of lucerne left soils initially low in mineral N (mean 82 kg N/ha.m depth in April) for the establishment of the first crop, but this was not reflected in the subsequent N contents of crop biomass and grain. Autumn mineral N concentrations peaked 1–2 years after lucerne removal (mean 141 kg N/ha.m depth). Yields of first crops after lucerne were strongly dependent on growing season rainfall. When sowing commenced in a wet year, they were similar to, or greater than, the control, but when sown in a dry year, were substantially lower. When sowing commenced in a wet year, lucerne supplied additional N for a minimum of 2 crops. At least 3 crops were supplied with lucerne N when cropping commenced in a dry year. The inclusion of 2–3 years of lucerne into a continuous cropping sequence only decreased annual profitability by $AU40/ha. This work shows that short phases of lucerne (minimum of 3 years) followed by 3–4 crops can provide economically viable options for farmers and produce better hydrological outcomes than current annual-plant based cropping systems.
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Mohammadi, Amir H., Antonin Chapoy, Bahman Tohidi, and Dominique Richon. "Water Content Measurement and Modeling in the Nitrogen + Water System." Journal of Chemical & Engineering Data 50, no. 2 (March 2005): 541–45. http://dx.doi.org/10.1021/je049676q.
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Boon, PI, and S. Cain. "Nitrogen cycling in salt-marsh and mangrove sediments at Western Port, Victoria." Marine and Freshwater Research 39, no. 5 (1988): 607. http://dx.doi.org/10.1071/mf9880607.
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The metabolism of organic nitrogen compounds in sediments from salt-marsh (Sarcocornia quinqueflora) and mangrove (Avicennia marina) areas at Western Port, Victoria, was investigated. Organic nitrogen compounds were metabolized at potential rates of up to 3.9 �mol cmF3 day-1 for amino acids, 23 �mol cm-3 day-( for dipeptides, and 5 �mol cm-1 day-1 for an amide. These were higher than the rate of ammonium regeneration in the absence of added substrate (<0.08 �mol cm-3 day-1); this indicates that organic nitrogenous compounds play a major role in nutrient cycling in coastal sediments. Rates of some transformations were highly correlated with sediment organic-matter content, total nitrogen content or concentration of soluble reactive phosphorus in the sediments, but overall there were few significant correlations between metabolic rates and edaphic conditions. Degradation of organic nitrogenous compounds in these sediments is likely to be influenced strongly by the availability of phosphorus, the quantity and quality of detrital inputs, and the size and activity of microbial populations.
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Riffkin, Penny A., Paul E. Quigley, Fiona J. Cameron, Mark B. Peoples, and Janice E. Thies. "Annual nitrogen fixation in grazed dairy pastures in south-western Victoria." Australian Journal of Agricultural Research 50, no. 2 (1999): 273. http://dx.doi.org/10.1071/a98034.
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Amounts of biologically fixed nitrogen (kg N/ha) were determined in grazed dairy pastures in 3 different areas of south-western Victoria over 12 months between October 1995 and 1996 using measurements of pasture growth, botanical composition, and the 15N natural abundance of white clover (Trifolium repens) and non-legume components. Estimates of the amounts of N fixed, based on N in clover shoots, were similar in each pasture (11, 16, and 18 kg N/ha.year), despite different environmental and management conditions. These on-farm determinations were low compared with experimental studies on N fixation by white clover undertaken in New Zealand (224–291 kg N/ha.year) and elsewhere in Australia (44–135 kg N/ha). Low fixation levels were attributed to low pasture yields (average 8.2 t dry matter (DM)/ha.year) and poor legume content in the swards (average 8%). Despite this, most of the white clover N was derived from atmospheric N2 (65%), and therefore, N fixation could potentially be playing an important role in the N economy of milk production on these farms.
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Shesterkin, V. Р., and N. M. Shesterkina. "NUTRIENTS CONTENT IN WATER OF THE BUREYSKY RESERVOIR IN THE HIGH-WATER YEAR OF 2021." Regional problems 25, no. 3 (2022): 63–65. http://dx.doi.org/10.31433/2618-9593-2022-25-3-63-65.
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The paper presents the research results on the content of nitrogen mineral forms and phosphorus in water of the Bureysky reservoir in the high-water year of 2021. The highest content of ammonium nitrogen was determined at the Tuyun site bottom water layer, and of nitrate nitrogen – at the Priplotinny site. The average concentration of ammonium nitrogen was found to be 0.026 mg N/l, of nitrate nitrogen – 0.077 mg N/l, and of mineral phosphorus – 0.0013 mg R/l.
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Gwaiseuk, WR, Rees H. van, and JHG Holmes. "Digestibility of Alpine Pasture on the Bogong High Plains of Victoria." Rangeland Journal 8, no. 1 (1986): 67. http://dx.doi.org/10.1071/rj9860067.
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The digestibility of the diet of cattle on the Bogong High Plains, in Victoria, was above 70% from the beginning of the grazing season in December 1982 until mid-March 1983, then fell to 63.5% at the end of the season in late March. Nitrogen content declined steadily from 1.60% to 0.99% in shrubland, 1.40% to 0.93% in grassland, 1.28% to 0.85% in mossbeds. The management implications are discussed.
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., L. Kota Prasad, Biplab Saha ., Abdul Haris ., K. Rajan ., and Sita Ram Singh . "Critical Grain Nitrogen Content for Optimizing Nitrogen and Water in Rice (Oryza sativa)." Journal of Biological Sciences 2, no. 11 (October 15, 2002): 746–47. http://dx.doi.org/10.3923/jbs.2002.746.747.
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Arora, A., V. P. Singh, and J. Mohan. "Effect of Nitrogen and Water Stress on Photosynthesis and Nitrogen Content in Wheat." Biologia plantarum 44, no. 1 (March 1, 2001): 153–55. http://dx.doi.org/10.1023/a:1017911513854.
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Archer, MJ, and L. O'Brien. "A comparative study of the quality status of Condor Wheat grown in Northern Victoria and Southern New South Wales." Australian Journal of Agricultural Research 38, no. 3 (1987): 465. http://dx.doi.org/10.1071/ar9870465.
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Australian Wheat Board quality advisers had formed the opinion that Condor wheat (Trificum aestivum L.) grown in north-west Victoria possessed weaker dough properties than that grown in southern New South Wales, even at similar grain protein contents. Samples of commercially grown Condor wheat from north-west Victoria and southern New South Wales were collected by Australian Wheat Board field officers to objectively investigate this observation. Testing of these samples indicated Condor grown in north-west Victoria to have significantly weaker dough properties than that grown in southern New South Wales. Doughs were less tolerant to mixing in the farinograph and had reduced extensograph maximum resistance, even when there was no difference in protein content between the samples from the two regions. The reduced dough strength in the Victorian samples was associated with lower nitrogen: sulfur ratios and residue protein content and fewer rheologically important disuifide groups per 50 g of flour. These differences were presumed to have resulted from some aspect of the environment during plant growth and development.
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Flood, R. G., and P. J. Martin. "Nitrogen accumulation and distribution at anthesis and maturity in ten wheats grown at three sites in north-western Victoria." Australian Journal of Experimental Agriculture 41, no. 4 (2001): 533. http://dx.doi.org/10.1071/ea98025.
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Plant nitrogen relationships were studied in 10 wheat cultivars sown at 3 sites (Horsham, Boort and Walpeup) in north-western Victoria by determining the nitrogen concentration and nitrogen content of plant components at anthesis and maturity. While the concentration of nitrogen varied in different plant components, whole plants at anthesis had a nitrogen concentration below the value required for maximum growth. The time to anthesis had an influence only on grain yield and grain nitrogen percentage at Horsham. Total assimilation of nitrogen at both anthesis and maturity was more strongly correlated to plant dry matter than plant nitrogen concentration. There was a significant negative correlation between grain nitrogen percentage and both nitrogen harvest index and harvest index. Grain yield was strongly correlated with total nitrogen accumulated at anthesis and more strongly correlated with total nitrogen accumulated at maturity. Grain yield was significantly correlated with nitrogen harvest index and more strongly correlated with harvest index. Grain yield was negatively correlated with grain nitrogen percentage. The negative association between grain nitrogen percentage and harvest index has important implications for the breeding of wheat with higher grain nitrogen percentage while maintaining or increasing grain yield. The results indicated that none of the measured parameters could be used for indirect selection aimed at improving grain nitrogen percentage.
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Corti, Martina, Pietro Marino Gallina, Daniele Cavalli, and Giovanni Cabassi. "Hyperspectral imaging of spinach canopy under combined water and nitrogen stress to estimate biomass, water, and nitrogen content." Biosystems Engineering 158 (June 2017): 38–50. http://dx.doi.org/10.1016/j.biosystemseng.2017.03.006.
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Smykla, Jerzy, Nataliia Iakovenko, Miloslav Devetter, and Łukasz Kaczmarek. "Diversity and distribution of tardigrades in soils of Edmonson Point (Northern Victoria Land, continental Antarctica)." Czech Polar Reports 2, no. 2 (June 1, 2012): 61–70. http://dx.doi.org/10.5817/cpr2012-2-6.
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This work contributes to the knowledge on distribution, diversity and ecology of the Antarctic soil biota. Different soil habitats from several ice-free coastal sites were sampled along the Victoria Land across 7° of latitude from 71° to 78°S during five austral summer seasons between 2003/04 and 2011/12. In this paper we report preliminary data on soil tardigrades (water bears) from Edmondson Point, Northern Victoria Land. Tardigrades were found to be present in 23 of the 41 examined soil samples (56%). Their presence was associated exclusively with soil samples collected from bryophytes communities and under cyanobacterial mats, whereas they were completely absent in fellfield and ornithogenic soils. Tardigrades were least numerous among all soil micrometazoans, their abundance in the positive samples was very variable and ranged from 3 to 1824 individuals per 100 g of soil DW. High water content seemed to be the major factor determining occurrence of tardigrades in the soils investigated. On the other hand low water content and toxic compounds from penguin guano seemed to act as a strong constraint on their existence in the Antarctic soils. Taxonomic evaluation of the extracted tardigrades revealed presence of only two species belonging to class Eutardigrada: Acutuncus antarcticus (Richters, 1904) and Milnesium antarcticum Tumanov, 2006. While A. antarcticus has already been reported previously as the most widespread and abundant tardigrade across the Victoria Land, the information on M. antarcticum is novel, both for Victoria Land and the continental Antarctica.
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SEGINER, I. "Modelling Ontogenetic Changes of Nitrogen and Water Content in Lettuce." Annals of Botany 94, no. 3 (August 3, 2004): 393–404. http://dx.doi.org/10.1093/aob/mch155.
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Paul, K. I., P. J. Polglase, A. M. O'Connell, J. C. Carlyle, P. J. Smethurst, and P. K. Khanna. "Soil nitrogen availability predictor (SNAP): a simple model for predicting mineralisation of nitrogen in forest soils." Soil Research 40, no. 6 (2002): 1011. http://dx.doi.org/10.1071/sr01114.
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A new empirical model (SNAP) combines a simple laboratory measurement of the basal rate of N mineralisation with the modifying effects of daily temperature and water content to predict seasonal and annual rates of mineralisation of forest soils. Short-term (20-60-day) aerobic incubations of either undisturbed or bulked and mixed soil were found suitable for prediction of the basal rate of N mineralisation. Data from laboratory incubations of a range of soils were used to calibrate empirical relationships describing the effects of temperature (Tm) and water (Wm) on rates of N mineralisation. Submodels for predicting daily average temperature (STUF) and water content (SWUF) for up to 3 surface soil layers were developed and used to provide inputs to the Tm and Wm functions, respectively. Inputs required for SNAP are restricted to variables whose values are easily obtained. In addition to the amount of N mineralised during a short aerobic laboratory incubation, other soil properties required are bulk density, gravel and clay content, and upper and lower limits of soil water content. Climatic data required included daily air temperature, rainfall, and solar radiation. Other inputs are slope, leaf area index of the stand, and approximate mass and height of litter. Predicted rates of N mineralisation have been verified using data from 9 native forests, 12 radiata pine plantations, and 12 eucalypt plantations from across southern Australia. Despite the wide range of forest types, soil types, climatic regions, and management systems, predicted annual rates of N mineralisation were in close agreement with those observed in the field, regardless of whether daily soil temperature and water content were predicted (R2 = 0.76, P < 0.001, n�=�127) or observed (R2 = 0.78, P < 0.001, n = 68). Sensitivity analysis showed that it was most important to minimise analytical error in inputs used to calculate the basal rate of N mineralisation (i.e. soil temperature, water content, and N mineralised during laboratory incubation). The model was more sensitive to daily soil temperature than to daily soil water content.
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Greenwood, K. L., G. N. Mundy, and K. B. Kelly. "On-farm measurement of the water use and productivity of maize." Australian Journal of Experimental Agriculture 48, no. 3 (2008): 274. http://dx.doi.org/10.1071/ea06094.
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Maize, as a C4 species, is likely to use water more productively than the perennial ryegrass and white clover pastures typically grown for dairy cows in northern Victoria. However, only estimates of water use by irrigated maize crops are available for this region. We measured the growth and water use of three commercial maize crops used for silage in northern Victoria. Crops under centre pivot irrigation were monitored in 2003–04 (Spray 1) and 2004–05 (Spray 2). A border-check irrigated crop (Border-check) was monitored in 2004–05. The Spray 1 crop was irrigated 30 times and received 782 mm of rainfall and irrigation. The crop yielded 22 t DM/ha, giving a water productivity of 28 kg DM/ha.mm (including irrigation, rainfall and change in soil water content). In the cooler, wetter summer of 2004–05, the water productivity was 34 kg DM/ha.mm for the Spray 2 crop and 30 kg DM/ha.mm for the Border-check crop. Crop evapotranspiration was estimated from weather data and a daily soil water balance was computed according to FAO 56. The estimated and measured changes in soil water content were in good agreement and indicated that the basal crop coefficients in the model (Kcb = 1.15 during the mid-season, before correction for non-standard humidity and wind speed) were appropriate to local conditions. Maize grown for silage in northern Victoria has higher water productivity than pastures. However, high yields are required to make it economically viable compared with alternative forages for dairy cows. These data will assist dairy farmers to select the optimum forage mix for their enterprises.
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Stockdale, CR. "The nutritive value of subterranean clover herbage grown under irrigation in northern Victoria." Australian Journal of Agricultural Research 43, no. 6 (1992): 1265. http://dx.doi.org/10.1071/ar9921265.
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A series of experiments is described which considered the nutritive value of subterranean clover (Trifolium subterraneum) herbage grown under irrigation in northern Victoria. Digestion studies were undertaken with sheep and dairy cows and the degradation of herbage samples in nylon bags was evaluated. Digestion coefficients were estimated, 1eaf:stem ratios were measured, mineral and amino acid profiles were obtained, and protein degradabilities were assessed. The digestibility and chemical composition of freshly cut subterranean clover herbage was relatively constant until wilting of the herbage in mid spring. With few exceptions, in vivo DM digestibility and nitrogen content were greater than 75% and 3.2%, respectively, and neutral detergent fibre, acid detergent fibre and lignin were less than 40%, 30% and 6%, respectively. The chemical composition of leaves and petioles/stems were very different. The digestibility of the leaf fraction was often much lower than that of petiole/stem, but its nitrogen content was higher. Reasons for this, and their implications, are discussed. Discussed also are the adequacy of herbage minerals and their solubilities. Rumen protein degradability for vegetative herbage ranged from 0.51 to 0.64. Of the plant components, the protein in stems was more degradable than the protein in leaves. The effects of incubation of herbage in nylon bags in the rumen for 24 h on amino acid composition are also discussed.
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Murakami, Keiichi, Masayuki Hara, Takuya Kondo, and Yohey Hashimoto. "Increased total nitrogen content of poultry manure by decreasing water content through composting processes." Soil Science and Plant Nutrition 57, no. 5 (October 2011): 705–9. http://dx.doi.org/10.1080/00380768.2011.616856.
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Norton, R. M., and N. G. Wachsmann. "Nitrogen use and crop type affect the water use of annual crops in south-eastern Australia." Australian Journal of Agricultural Research 57, no. 3 (2006): 257. http://dx.doi.org/10.1071/ar05056.
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The effect of management and crop selection on water use and profile drying was investigated using 2 series of experiments conducted in the Victorian Wimmera. The effect of applied nitrogen on growth and water use of canola was assessed from 3 field experiments on a Vertosol soil. Across these sites, 140 kg N/ha increased crop water use by a mean of 30 mm, and the biological response averaged 3.68 t/ha of shoot dry matter and seed yield increased by 73% from 1.46 to 2.52 t/ha. The additional nitrogen enabled roots to go deeper into the soil and also to extract water to higher tensions, but the increases in water use were far less than the growth and yield responses. Estimated average soil evaporation was 120 mm across these experiments, but ranged from 26 to 57% of total water use. It was concluded that increased crop vigour in response to applied nitrogen does increase total water use, but the main way that water-use efficiency increases is through reduced soil evaporation. In a second series of experiments, the growth, yield, and water use of wheat, canola, linseed, mustard, and safflower were compared across 4 sites with differing soil moisture contents. Wheat was the highest yielding crop at all sites. Mustard and canola produced similar amounts of biomass and seed yields, whereas linseed produced seed yields that were generally less than the brassica oilseeds. Safflower grew well and produced large amounts of biomass at all sites, but this increased growth did not necessarily translate into increased seed yields. Safflower yielded less seed than all other crops at the 2 dry sites, but yields were similar to canola at the wetter sites. On 2 drier sites, soil water extraction occurred to approximately 1 m for all crops, and all available water was used within that zone by all crops. Where the soil was wet beyond 1 m, safflower was able to extract water from deeper in the profile than the other crops and generated a soil water deficit of about 100 mm more than the other crops at maturity. This deficit persisted into the subsequent autumn–winter period. The potential of using safflower as a management option to extract water from deep in the profile, and so create a soil buffer, is discussed.
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Liu, Shenghua, Yongyi Zhang, Yuan Lin, Zhigang Zhao, and Qingwen Li. "Tailoring the structure and nitrogen content of nitrogen-doped carbon nanotubes by water-assisted growth." Carbon 69 (April 2014): 247–54. http://dx.doi.org/10.1016/j.carbon.2013.12.023.
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Xie, S. X., X. Y. Xiong, Q. M. Zheng, and Y. C. Wu. "WATER STRESS AFFECTS GROWTH, RELATIVE WATER CONTENT, GAS EXCHANGE AND NITROGEN POOLS OF LOQUAT." Acta Horticulturae, no. 750 (August 2007): 261–68. http://dx.doi.org/10.17660/actahortic.2007.750.41.
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Marsh, NR, and MA Adams. "Decline of Eucalyptus tereticornis Near Bairnsdale, Victoria: Insect Herbivory and Nitrogen Fractions in Sap and Foliage." Australian Journal of Botany 43, no. 1 (1995): 39. http://dx.doi.org/10.1071/bt9950039.
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Eucalyptus tereticornis growing along roadsides and in pastures in eastern Victoria were often in poor health and were repeatedly defoliated by herbivorous insects. Epicormic buds sprouted following bouts of defoliation and the first epicormic leaves produced from such buds were rich in nitrogen and particularly in nitrogenous solutes such as proline compared with adult leaves. Xylem sap collected from declining trees was richer in nitrogenous solutes than that from healthy trees. Concentrations of total nitrogen and specific solutes in foliage were not closely related to pressure potential in shoots or to nitrogen availability in soil. In glasshouse-grown seedlings, foliar concentrations of total nitrogen and of a number of nitrogenous solutes were increased by reduced water availability. Chronic insect infestations and periodic insect outbreaks may be supported by high concentrations of nitrogenous solutes in sap and foliage, especially epicormic foliage, which in turn may be a response to drought or increasing salinity ('physiological drought').
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J. Mwita, C. "Determination of Heavy Metal Content in Water, Sediment and Microalgae from Lake Victoria, East Africa." Open Environmental Engineering Journal 4, no. 1 (September 23, 2011): 156–61. http://dx.doi.org/10.2174/1874829501104010156.
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O'Leary, G. J., and D. J. Connor. "A simulation study of wheat crop response to water supply, nitrogen nutrition, stubble retention, and tillage." Australian Journal of Agricultural Research 49, no. 1 (1998): 11. http://dx.doi.org/10.1071/a97020.
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A series of simulations was made with a fallow{wheat crop simulation model to examine the effects of stubble retention and tillage on yield for 2 semi-arid environments in north-western Victoria over a 100-200-year period. The fallow treatments comprised 4 combinations of stubble management and tillage in 18-month-long fallows of a fallow{wheat rotation. The 2 sites are representative of the major soil types of the region: a chromic vertisol at Dooen and a calcic xerosol at Walpeup. Stubble retention had the greatest effect on yield, providing a median increase of 0·8 and 0·6 t/ha at Dooen and Walpeup, respectively. Zero tillage had an importantbut small advantage in the presence of stubble at Dooen (0·2 t/ha) and no significant advantage under any system at Walpeup. Yield response was primarily caused through increased fallow-stored water of approximately 89 and 25 mm at Dooen and Walpeup, respectively. The accumulation of soil mineral nitrogen (SMN) at sowing in fallows did not show the same treatment differences as with water or yield. There was a significant interaction between soil type and fallow method. At Dooen, stubble depressed SMN by about 24 kg N/ha (163{185 kg N/ha) below those without stubble (188-207 kg N/ha). Tillage reduced SMN with or without stubble by about 20 kg N/ha. At Walpeup, on the other hand, the highest SMN was associated with tillage and was enhanced by stubble, but the differences were small (<10 kg N/ha). Nitrogen fertiliser produced a small increase in yield (median 0·2 t/ha) at Dooen, increasing to about 0·4 t/ha in wetter years when stubble was retained and fallows were maintained with zero tillage. Over a 100-year period, nitrogen fertiliser reduced the rate of yield decline. The use of nitrogen fertiliser with stubble retention and zero tillage offers an opportunity for arresting declining yield and quality in intensive cropping systems in the Wimmera region of Victoria.
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Wu, Hai Xia, Dong Juan Cheng, Li Jia Wang, and Liu Liang. "Influence of Film Hole Diameter on Soil Water and Nitrogen Transport and Distribution Characteristic under Facilities Conditions." Advanced Materials Research 538-541 (June 2012): 141–45. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.141.
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Through the facilities imitating experiment of film hole irrigation with nitric acid potassium solution under different film hole diameter, the content of soil water and nitric nitrogen was determined and analyzed in the different time after irrigation. The result shows: the content of soil water and nitric nitrogen under different film hole diameter reduced with time and achieved the maximum at the center while it is reverse away from film hole; soil water content decreased with the increase of film hole diameter at the same position while the nitric nitrogen content was opposite. The influence of the increase of film hole diameter on soil water and nitric nitrogen distribution is harm for plant to absorb water and nitric nitrogen, so it will be better to reduce the film hole diameter in the agriculture production. The result provided the proof for the sustainable development of facilities agriculture and evaluating the effect of nitrogen on environment.
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Jakubaszek, Anita. "Nitrogen and Phosphorus Content in Constructed Wetlands." Civil and Environmental Engineering Reports 30, no. 2 (June 1, 2020): 247–57. http://dx.doi.org/10.2478/ceer-2020-0030.
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AbstractHigh effectiveness of organic pollutants and nutrients removal is achieved in biological wastewater treatments plants – in case of proper exploitation of these objects. Nitrogen and phosphorus transformation or removal depends on many physic – chemical and biochemical conditions, deposit and environmental factors. A rule for treating wastewater consists in decomposition of organic compounds included in wastewater in water-soil environment. Removing contaminations is performed as a result of sorption of contaminations, bio-chemical oxidation-reduction reactions and biological activity of soil microorganisms and hydrophyte flora. The research has been carried out in the constructed wetland in Małyszyn (1300 EP). The treatment plant operates in horizontal system, with under-surface flow of wastewater.
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Holland, J. E., T. H. Johnston, R. E. White, and B. A. Orchard. "An investigation of runoff from raised beds and other tillage methods in the high rainfall zone of south-western Victoria, Australia." Soil Research 50, no. 5 (2012): 371. http://dx.doi.org/10.1071/sr11200.
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For many years, the poor physical and hydraulic properties of the soils in south-western Victoria have restricted crop production due to waterlogging. In this region of predominantly winter rainfall, raised beds have become popular with farmers to overcome these difficulties; however, little has been reported on the hydrology of raised beds compared with other tillage systems for cropping in the rain-fed environment of south-western Victoria. This study measured rainfall characteristics, runoff volumes, and soil properties such as the soil water content, bulk density, and hydraulic conductivity for three tillage treatments (raised beds, conventional cultivation, and deep cultivation) over 6 years on a Sodosol at a field site near Geelong, Victoria. Runoff was regressed against rainfall variables such as the amount per event, hours of rainfall, rainfall intensity, and maximum rainfall intensity to determine the significance of any differences between the treatments. The relationship between runoff and rainfall amount was best described with an exponential model. Raised beds significantly increased the amount of runoff relative to the other treatments when above-average rainfall was received, but there was little difference in runoff in years of below-average rainfall. No consistent effect of runoff on crop biomass was detected nor could any differences in runoff be attributed to differences in soil water content, hydraulic conductivity, and bulk density between treatments. The most important factor appeared to be the furrows between the raised beds, which acted as conduits for the flow of surface water during the larger storm events. During such events, runoff is an important hydrological process in cropping land in south-western Victoria.
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Wolska, Małgorzata. "Changes in water biostability levels in water treatment trials." Water Science and Technology 71, no. 4 (June 24, 2014): 538–44. http://dx.doi.org/10.2166/wst.2014.288.
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This article presents the results of studies of changes in water biostability levels in water treatment systems. In order to evaluate the potential of microorganism regrowth, both the organic and non-organic nutrient substrate content was taken into account. Pre-treatment in the analyzed water treatment plants ensured high phosphate ion removal effectiveness but a significantly worse effectiveness in removing biodegradable dissolved organic carbon (BDOC). Lowering nutrient substrate content during the main treatment stage was only possible in water treatment systems that incorporated biological processes. Conversely, final water treatment processes only influenced BDOC content in the treated water. Irrespective of the water type and unit treatment process, the limiting factors for microorganism regrowth in the distribution system were the phosphate ion content and BDOC content. However, none of the analyzed treatment systems ensured a reduction in non-organic nitrogen content that would ensure biological stability of the water.
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Olalde G., Víctor M., J. Alberto Escalante E., and Angel A. Mastache L. "PHENOLOGY, YIELD AND WATER USE EFFICIENCY OF SUNFLOWER IN FUNCTION OF ENVIRONMENT AND NITROGEN / FENOLOGIA, RENDIMIENTO Y EFICIENCIA EN EL USO DEL AGUA EN FUNCION DEL AMBIENTE Y NITRÓGENO / PHÉNOLOGIE, RENDEMENT ET EFFICACITÉ DE L’UTILISATION DE L’EAU EN FONCTION DES ENVIRONS ET DE L’AZOTE CHEZ LE TOURNESOL." HELIA 24, no. 35 (December 2001): 111–28. http://dx.doi.org/10.1515/helia.2001.24.35.111.
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SUMMARYDuring the rainy season of 1998, a field experiment was established in Cocula, Guerrero (hot subhumid climate, Awo) and in Montecillo, México (semiarid climate, BS1), to evaluate the effect of nitrogen (0, 10 and 20 g m-2) and environment on phenology, yield and its components, water use efficiency (WUE), and crop evapotranspiration (ETc) and heat units (HU) accumulated during the growth cycle of sunflower (Helianthus annuus L.) cv. Victoria. The crop was planted on June 1 at a density of 7.5 pl m-2 in both climates. In Cocula, maximum and minimum temperatures were more extreme and rainfall was more intense, while soil was poor in total nitrogen, compared with Montecillo. Crop growth, yield and its components, and water use efficiency were affected significantly by the environment, nitrogen and the interaction environment * nitrogen. The crop cycle in the hot environment was 36 days shorter, with a greater accumulation of HU and ETc. Yield and its components and water use efficiency were significantly higher in Cocula. Nitrogen positively affected the evaluated variables. The interactive effect of environment * nitrogen was observed clearly, since in Cocula there was response to the application of nitrogen in most of the variables evaluated, while in Montecillo there was not.
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Zhu, Juanjuan, Nicolas Tremblay, and Yinli Liang. "A Corn Nitrogen Status Indicator Less Affected by Soil Water Content." Agronomy Journal 103, no. 3 (May 2011): 890–98. http://dx.doi.org/10.2134/agronj2010.0351.
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Wilson, E., and N. Serpokrylov. "Ammonium nitrogen content regulation in sewage water at the transportation stage." IOP Conference Series: Materials Science and Engineering 698 (December 18, 2019): 055044. http://dx.doi.org/10.1088/1757-899x/698/5/055044.
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Paul, K. I., P. J. Polglase, A. M. O'Connell, J. C. Carlyle, P. J. Smethurst, and P. K. Khanna. "Defining the relation between soil water content and net nitrogen mineralization." European Journal of Soil Science 54, no. 1 (February 21, 2003): 39–48. http://dx.doi.org/10.1046/j.1365-2389.2003.00502.x.
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Belov, Aleksandr, Aleksey Vasil'ev, Yuriy Stepanychev, and Anton Sharko. "EFFECT OF ELECTROHYDRAULIC TREATMENT ON NITRATE NITROGEN CONTENT IN IRRIGATION WATER." Vestnik of Kazan State Agrarian University 15, no. 3 (November 30, 2020): 54–57. http://dx.doi.org/10.12737/2073-0462-2020-54-57.
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The introduction of mineral fertilizers has a negative impact on the agrobiocenosis. An increase the concentration of nitrate nitrogen in irrigation water in order to use it as a nitrogen fertilizer that does not have a negative impact on the environment seems relevant. The change in the content of nitrate nitrogen was determined in irrigation water, which was used as the flowing water of the city water supply (Moscow); pond water (Moscow region); potassium nitrate solution with a concentration of 50.9 mg/l. Three types of irrigation water were processed using a high-voltage installation. The experimental electrohydraulic installation consisted of a TVI-50/70 transformer with a rectifier unit; DC electric energy storage systems (high-voltage pulse capacitors); arresters designed to generate pulsed spark discharges with a short rise time; controls that allow changing technological modes during experiments; working units. During the research, an ITAN pH meter/ionometer was used according to the RD 52.24.367-2010 method. The technological mode of operation of the electro-hydraulic unit provides for the following characteristics: operating voltage 42 kV; capacitance of capacitors 0.05 μF; number of spark discharges n = 1 ... 5 thousand pieces; forming the gap between the ball arresters FP = 14 mm; working gap between working high-voltage electrodes 10 mm. Electrohydraulic treatment of water increases the concentration of nitrate nitrogen compounds in the running water of city water supply by 3.7 times (from 2.9 to 10.9 mg/l), in pond water - by 7 times (from 1.2 to 8.4 mg/l), in a solution of potassium nitrate - 1.3 times (from 50.9 to 68.4 mg/l). In water treated electrohydraulically, the content of nitrate nitrogen increases, which expands the possibilities for its use when watering plants.