scholarly journals The flows and balances of P, K, Ca and Mg on intensively managed Boreal high input grass and low input grass-clover pastures

2014 ◽  
Vol 23 (2) ◽  
pp. 106-117 ◽  
Author(s):  
Kirsi Järvenranta ◽  
Perttu Virkajärvi ◽  
Helvi Heinonen-Tanski
Keyword(s):  
Surface Runoff ◽  
Nutrient Balances ◽  
High Input ◽  
Low Input ◽  
P Loss ◽  
Ley Farming ◽  
P Balance ◽  
Intensively Managed ◽  
Total P ◽  
Better Than

The main objective of the study was to compare nutrient balances of phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca) on fertilized grass pasture (high input) and unfertilized grass-clover pasture (low input) both grazed by dairy cattle. The second aim was to quantify P loss in surface runoff from the fertilized grass pasture. The study was conducted on a lysimeter field that included two surface runoff collector ditches. The whole area was rotationally stocked five times per year and the amount of milk was recorded. Nutrient balances were negative on both grass and grass-clover pastures except the P balance for grass pasture, which was 18 kg ha-1 positive. The amount of total P in the surface runoff from fertilized grass pasture was 1.2–0.9 kg ha-1 y-1. It seems that in short-term ley farming, grass-clover swards can retain nutrients in the soil better than pure grass swards.

Bioavailability of phosphorus as a tool for efficient P reduction schemes

1998 ◽  
Vol 37 (3) ◽  
pp. 241-247 ◽  
Author(s):  
Peter Gerdes ◽  
Sabine Kunst
Keyword(s):  
Sewage Treatment ◽  
Cost Effective ◽  
Effective Management ◽  
Lower Saxony ◽  
Effective Strategies ◽  
P Balance ◽  
Different Sources ◽  
Total P ◽  
P Sources ◽  
P Bioavailability

The bioavailability of phosphorus from different sources has been evaluated in the catchment area of the River Ilmenau (Lower-Saxony, Germany) by using algal assays. The P bioavailability describes the different potential of P from various sources of supporting eutrophication. Effluents from sewage treatment plants were highly bioavailable (72% of TP) whereas rainwater (26%) and erosion effluents (30%) showed a low bioavailability. In order to develop effective strategies to minimize P inputs into the river, source specific P bioavailability indices were determined and combined with a P balance to calculate inputs of vioavailable P (BAP) instead of total P (TP). It could be shown that the relative importance of the different P sources changes when applying BAP. Measures to reduce P inputs into the River Ilmenau will take P bioavailability into consideration and therefore lead to a more cost-effective management.

The impact of biomass harvesting on phosphorus uptake by wetland plants

2001 ◽  
Vol 44 (11-12) ◽  
pp. 61-67 ◽  
Author(s):  
S-Y. Kim ◽  
P.M. Geary
Keyword(s):  
Plant Biomass ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Plant Parts ◽  
Biomass Harvesting ◽  
Below Ground ◽  
The Impact ◽  
Total P ◽  
Better Than ◽  
P Removal

Two species of macrophytes, Baumea articulata and Schoenoplectus mucronatus, were examined for their capacity to remove phosphorus under nutrient-rich conditions. Forty large bucket systems with the two different species growing in two types of substrate received artificial wastewaters for nine months, simulating a constructed wetland (CW) under high loading conditions. Half of the plants growing in the topsoil and gravel substrates were periodically harvested whereas the other half remained intact. Plant tissue and substrate samples were regularly analysed to determine their phosphorus concentrations. With respect to phosphorus uptake and removal, the Schoenoplectus in the topsoil medium performed better than the Baumea. Biomass harvesting enhanced P uptake in the Schoenoplectus, however the effect was not significant enough to make an improvement on the overall P removal, due to the slow recovery of plants and regrowth of biomass after harvesting. From P partitioning, it was found that the topsoil medium was the major P pool, storing most of total P present in the system. Plant parts contributed only minor storage with approximately half of that P stored below ground in the plant roots. The overall net effect of harvesting plant biomass was to only remove less than 5% of total phosphorus present in the system.

scholarly journals Efficiency Enhancement of Flexible Mode Bridgeless Boost Rectifier

2019 ◽  
Vol 9 (2) ◽  
pp. 1503-1508
Keyword(s):  
Power System ◽  
Input Voltage ◽  
Efficiency Enhancement ◽  
Fast Recovery ◽  
High Input ◽  
Voltage Range ◽  
Low Input ◽  
Flexible Mode ◽  
Simulation Results ◽  
Boost Rectifier

Most of the devices in power system become faulty due to the large content of harmonics present in voltage and current. It is mainly caused by the conduction losses in the system. At first, it is necessary to determine the extent of harmonic present by calculating the total harmonic distortions i.e., root over sum of the integral harmonics divide by fundamental harmonic. Later, identification of type of method for reducing harmonics is essential. In this project we are mainly focusing on two types of PFC bridge boost rectifier to improve the efficiency for low and high input voltage range. It using back to back bridgeless PFC boost rectifier for high input voltage and for low input voltage range, three level bridgeless boost rectifiers respectively. Fast recovery diode instead of normal diodes for better reliability and efficiency is utilized. The end model is obtained by combining two circuits BTBBL (Back to back bridgeless boost PFC) and TLBL (Three level bridgeless boost PFC) to get the FMBL (Flexible mode bridgeless boost PFC). Due to presence of less no of components, conduction losses are less hence less distortion is observed with improved efficiency. A simulation is carried out for all three models using MATLAB Simulink platform. In hardware, TLP250 driver for MOSFET is used and which is interfaced with PIC microcontroller. The hardware results are obtained that validates the simulation results.

scholarly journals Runoff Characteristics of Total-N and Total-P in Upland Surface Runoff Treated with Livestock Manure Compost

2012 ◽  
Vol 54 (6) ◽  
pp. 29-37 ◽  
Author(s):  
Jin Kyu Choi ◽  
Jae Gwon Son ◽  
Hyun Jeong Lee ◽  
Young Joo Kim
Keyword(s):  
Surface Runoff ◽  
Livestock Manure ◽  
Total N ◽  
Manure Compost ◽  
Livestock Manure Compost ◽  
Total P

scholarly journals Land Use Scenarios and Their Effect on Potential Crop Production: The Case of Gambella Region, Ethiopia

Agriculture ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 105 ◽  
Author(s):  
Azeb W. Degife ◽  
Florian Zabel ◽  
Wolfram Mauser
Keyword(s):  
Land Use ◽  
Crop Production ◽  
Agricultural Intensification ◽  
Irrigated Agriculture ◽  
High Input ◽  
Low Input ◽  
Land Use Scenarios ◽  
Food Shortages ◽  
Increase Food Production ◽  
Caloric Requirements

Agricultural intensification and cropland expansion are the key policies to increase food production in Ethiopia. Gambella is one of the regions in Ethiopia which is highly suitable for agriculture; however, the local people still face food shortages. We therefore investigated the potential for intensification and cropland expansion. In this study, we developed land use scenarios of agricultural intensification and expansion and analysed their effect on potential crop production in the region and estimated the population that could be nourished as a result. We distinguished between different degrees of intensification, ranging from low input rainfed to high input irrigated agriculture and different degrees of expansion, considering the best 30% or 50% of land to be utilized for expansion. While the results reveal that irrigation had almost no effect on potential yields, they also show that the potential calorie production in all scenarios far exceeds the current and possible future caloric requirements of Gambella’s population. For example, for the top 50% expansion scenario, calorie production increased by +428% for the low input and by +1092% for the high input scenarios. Thus, Gambella could nourish up to 21 million people and serve as a bread basket for the entire country, which could improve national food security.

scholarly journals Phosphorus loss potential and phosphatase activities in paddy soils

2013 ◽  
Vol 59 (No. 11) ◽  
pp. 530-536 ◽  
Author(s):  
S. Wang ◽  
X. Liang ◽  
G. Liu ◽  
H. Li ◽  
X. Liu ◽  
...  
Keyword(s):  
Shallow Groundwater ◽  
Paddy Soils ◽  
Pig Manure ◽  
Lake Basin ◽  
Phosphatase Activities ◽  
Olsen P ◽  
P Loss ◽  
Free Treatment ◽  
P Fertilizer ◽  
Total P

The effects of phosphorus (P) fertilizer on P loss potential, soil Olsen-P and neutral phosphatase activities in paddy soils fertilized with superphosphate or pig manure (PM) were evaluated in this paper. Data were collected from a field experiment in the Tai Lake Basin, China. Superphosphate rates were 0, 17.5, 26.7, and 35.0 kg P/ha, and PM rates were 0, 1.4, 2.1, and 2.8 t/ha for each crop, respectively. Soil Olsen-P in the plow layer increased to a greater extent with PM than with superphosphate. Pig manure increased neutral phosphatase activities in the plow layer compared with PM-free treatment. In contrast, superphosphate inhibited neutral phosphatase activities compared with superphosphate-free treatment. Spring application of P fertilizer markedly increased the total P of surface water in November (< 0.01 vs. 0.10 mg/L) compared with P-free treatment. The total P of shallow groundwater at a 75 cm depth was ~0.01 mg/L. Phosphorus fertilizer did not influence Olsen-P or neutral phosphatase activities under the plow layer. Downward movement of P did not occur. Appropriate rate of P application of 26.2 kg P/ha for each crop in this soil reduced the risk of P loss in the paddy wetland ecosystem.

A comparison of some surface soil phosphorus tests that could be used to assess P export potential

Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  
Keyword(s):  
Organic P ◽  
Soil Tests ◽  
Soil P ◽  
Olsen P ◽  
P Sorption ◽  
P Loss ◽  
Extractable P ◽  
Soil P Tests ◽  
Total P ◽  
Water Extractable

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.

Study on Four Different Vegetation Types Treating the Sanitary Sewage

2011 ◽  
Vol 105-107 ◽  
pp. 1985-1990
Author(s):  
Ming Tao Zhou ◽  
Ping Yang
Keyword(s):  
Water Quality ◽  
Surface Runoff ◽  
Festuca Arundinacea ◽  
Cynodon Dactylon ◽  
Vegetation Type ◽  
Vegetation Types ◽  
Total Removal ◽  
Artificial Surface ◽  
Quality Indexes ◽  
Better Than

The sanitary sewage is treated with four different vegetation types by means of artificial surface runoff. Results show soil+ Cynodon dactylon L. + Festuca arundinacea Schreb is the best vegetation type in treating the sanitary sewage, and the total removal of it is 80.24% TN, 62.99% TP, 74.85% BOD5, 39.73% COD and 58.64% TOC respectively in the course of trial, which indicates that the mixed vegetation type made up of plants and soil is better than the pure soil vegetation type, and the complementary collocation of complex plants is better than the single plant.Five water-quality indexes of the sanitary sewage removed by the single vegetation type are also studied, and it shows that there are some differences among them from high to low as follows: TN>BOD5>TP>TOC>COD.

Creeping Bentgrass (Agrostis Stolonifera) Tolerance to Sulfosulfuron

2008 ◽  
Vol 22 (3) ◽  
pp. 481-485 ◽  
Author(s):  
Patrick E. McCullough ◽  
Stephen E. Hart
Keyword(s):  
Weed Control ◽  
Creeping Bentgrass ◽  
Agrostis Stolonifera ◽  
Early Summer ◽  
Growth Chamber ◽  
Root Weight ◽  
Golf Courses ◽  
Growth Responses ◽  
Intensively Managed ◽  
Better Than

Sulfosulfuron was recently registered for grassy weed control in creeping bentgrass, but turf sensitivity is a concern for intensively managed golf courses. Field and growth chamber experiments in New Jersey investigated creeping bentgrass growth responses and tolerance to sulfosulfuron. Creeping bentgrass chlorosis increased with sulfosulfuron rate but turf had less chlorosis from sequential sulfosulfuron applications compared to bispyribac–sodium. Herbicide-treated turf had similar root weight compared to untreated turf on six sampling dates. In growth-chamber experiments, creeping bentgrass treated with sulfosulfuron had chlorosis and clipping weight reductions exacerbated by reductions in temperature from 25 to 15 C. Overall, creeping bentgrass appears to tolerate sequential sulfosulfuron applications better than or comparable to bispyribac-sodium in early summer, whereas creeping bentgrass sensitivity to sulfosulfuron increases at cooler temperatures.

scholarly journals Identification of soil P fractions that are associated with P loss from surface runoff under various cropping systems and fertilizer rates on sloped farmland

PLoS ONE ◽  
2017 ◽  
Vol 12 (6) ◽  
pp. e0179275 ◽  
Author(s):  
Xinghua Li ◽  
Baona Wang ◽  
Tewu Yang ◽  
Duanwei Zhu ◽  
Zhongnan Nie ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Cropping Systems ◽  
P Fractions ◽  
Soil P ◽  
Soil P Fractions ◽  
P Loss ◽  
Fertilizer Rates
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