Nitrogen and Phosphorus Leaching from Growing Season versus Year-Round Application of Wastewater on Seasonally Frozen Lands

2006 ◽  
Vol 35 (1) ◽  
pp. 324-333 ◽  
Author(s):  
Francis Zvomuya ◽  
Carl J. Rosen ◽  
Satish C. Gupta
Keyword(s):  
Growing Season ◽  
Phosphorus Leaching ◽  
Nitrogen And Phosphorus

Bacterioplankton, Phytoplankton, and Zooplankton Communities in a British Columbia Coastal Lake Before and After Nutrient Reduction

1986 ◽  
Vol 43 (8) ◽  
pp. 1504-1514 ◽  
Author(s):  
F. Joan Hardy ◽  
Ken S. Shortreed ◽  
John G. Stockner
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Inorganic Nitrogen ◽  
Size Fraction ◽  
Growing Season ◽  
Nutrient Reduction ◽  
Nitrogen And Phosphorus ◽  
Coastal Lake ◽  
Before And After ◽  
High Concentrations

Inorganic nitrogen and phosphorus were applied weekly during the growing season from 1980 to 1982 and twice weekly in 1983 to Hobiton Lake, a warm monomictic coastal lake in British Columbia. The lake was not fertilized in 1984. Average numbers of bacteria during the growing season decreased from a high of 1.53 × 106∙mL−1 in the fertilized condition to 0.84 × 106∙mL−1 in the unfertilized condition. Chlorophyll a concentrations decreased from a maximum seasonal average of 2.69 μg∙L−1 (1981) to 1.30 μg∙L−1 (1984), and algal numbers decreased from 5.83 × 104∙mL−1 (1983) to 2.29 × 104∙mL−1 (1984). Although the numbers of phytoplankton in each size fraction (picoplankton, nanoplankton, or microplankton) decreased in the unfertilized condition, the greatest change was an almost fourfold decrease in picoplankton, which consisted of 90% cyanobacteria (primarily Synechococcus spp.). Abundance of the large diatoms Rhizosolenia spp. and Melosira spp. increased in 1984, resulting in an increase in average seasonal algal volume. Average densities of medium (0.15–0.84 mm) and large (0.85–1.5 mm) zooplankton were greatest in 1982, while rotifers and small zooplankton (0.10–0.14 mm) were most dense in 1984 following nutrient reduction. The lake had relatively high concentrations of planktivorous juvenile sockeye salmon (Oncorhynchus nerka) that appeared to minimize any direct effect of nutrient additions on zooplankton densities.

Nitrogen and phosphorus leaching losses from paddy fields with different water and nitrogen managements

2011 ◽  
Vol 9 (3) ◽  
pp. 333-342 ◽  
Author(s):  
Shi-Zhang Peng ◽  
Shi-Hong Yang ◽  
Jun-Zeng Xu ◽  
Yu-Feng Luo ◽  
Hui-Jing Hou
Keyword(s):  
Paddy Fields ◽  
Phosphorus Leaching ◽  
Nitrogen And Phosphorus ◽  
Leaching Losses

Nitrogen and phosphorus leaching losses from intensively managed paddy fields with straw retention

2014 ◽  
Vol 141 ◽  
pp. 66-73 ◽  
Author(s):  
Jun Wang ◽  
Dejian Wang ◽  
Gang Zhang ◽  
Yuan Wang ◽  
Can Wang ◽  
...  
Keyword(s):  
Paddy Fields ◽  
Phosphorus Leaching ◽  
Nitrogen And Phosphorus ◽  
Leaching Losses ◽  
Straw Retention ◽  
Intensively Managed

Effect of times, height and frequency of defoliation on growth and development of Townsville stylo in pure ungrazed swards at Katherine, N.T

1973 ◽  
Vol 13 (63) ◽  
pp. 389 ◽  
Author(s):  
MJ Fisher
Keyword(s):  
Growth And Development ◽  
Growing Season ◽  
Nitrogen And Phosphorus ◽  
Pod Yield ◽  
Matter Production ◽  
Stylosanthes Humilis ◽  
Townsville Stylo ◽  
One Year ◽  
Complete Fertilizer ◽  
Cutting Height

A one-year experiment was done in the field at Katherine, Northern Territory, to determine the influence of defoliation at different times (January, February, and March) and heights (5, 13 and 20 cm) on the growth and development of Townsville stylo (Stylosanthes humilis) in ungrazed swards grown with complete fertilizer and irrigation. Townsville stylo withstood repeated defoliation at 5 cm provided that cutting started in January, but, when the first defoliation was delayed, single cuts at 5 cm in either February or March killed 82 and 53 per cent of the swards. Defoliation to 5 cm early in the season reduced total cumulative yield by less than 450 kg ha-1, and did not affect pod yield or nitrogen and phosphorus concentrations at the end of the growing season. Immediately after defoliation nitrogen and phosphorus concentrations were reduced, but there was rapid recovery to higher levels with 5-cm and the same levels with 13-cm defoliation. Successive defoliation at 4 3 cm in February and March increased yield of pods. Defoliation at both 5 and 13 cm increased relative growth rate compared with the control and less frequently defoliated treatments. Defoliation to 5 cm each four weeks altered the stand morphology to a dense mat of foliage at cutting height. The ability of Townsville stylo to withstand continued defoliation suggests that sustained grazing during the growing season may be successful in controlling grass weeds vulnerable to grazing without greatly reducing pod yield or total dry matter production of Townsville stylo.

Carbon, nitrogen and phosphorus leaching after site preparation at a boreal forest clear-cut area

2007 ◽  
Vol 243 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Sirpa Piirainen ◽  
Leena Finér ◽  
Hannu Mannerkoski ◽  
Michael Starr
Keyword(s):  
Boreal Forest ◽  
Site Preparation ◽  
Phosphorus Leaching ◽  
Nitrogen And Phosphorus ◽  
Clear Cut

Contribution of overwintering leaves to the growth of three broad-leaved, evergreen shrubs belonging to the Ericaceae family

1978 ◽  
Vol 56 (10) ◽  
pp. 1248-1261 ◽  
Author(s):  
R. J. Reader
Keyword(s):  
Growing Season ◽  
Leaf Nitrogen ◽  
Leaf Nitrogen Content ◽  
Nitrogen And Phosphorus ◽  
Southern Ontario ◽  
Plant Parts ◽  
Mature Leaves ◽  
Growing Seasons ◽  
Labrador Tea ◽  
Ledum Groenlandicum

Individual leaves of three bog ericads, leatherleaf (Chamaedaphne calyculata), bog laurel (Kalmia polifolia), and Labrador tea (Ledum groenlandicum), were retained for a maximum of two growing seasons in a peat bog in southern Ontario. The premature loss of mature leaves, resulting from artificial defoliation, significantly reduced the growth of new shoots of L. groenlandicum and K. polifolia but not of C. calyculata. Defoliation effects were directly proportional to the normal retention time for overwintering leaves. Mature leaves probably translocate photosynthate, nitrogen, and phosphorus to other plant parts. This would explain why leaf dry weights were greatest at the start, rather than at the end, of the leaves' second growing season. Net photosynthetic rates decreased with leafage, but in terms of leaf nitrogen content, new and old leaves fixed equal amounts of carbon.

scholarly journals The effect of anaerobic baffled reactor effluent on nitrogen and phosphorus leaching from four soils in a laboratory column experiment

Water SA ◽  
2018 ◽  
Vol 44 (1 January) ◽  
Author(s):  
Goitom Adhanom ◽  
Jeffrey Hughes ◽  
Alfred Odindo
Keyword(s):  
Flow Rate ◽  
Flow Direction ◽  
Column Experiment ◽  
High Flow ◽  
Silica Sand ◽  
Low Flow ◽  
Phosphorus Leaching ◽  
Internal Diameter ◽  
Nitrogen And Phosphorus ◽  
Anaerobic Baffled Reactor

Leaching of nitrogen and phosphorus from soil columns during application of anaerobic baffled reactor effluent was evaluated. The soils used were from Inanda (Ia), Cartref (Cf), and Sepane (Se) forms, and a silica sand (SS). Each was packed into duplicate columns (103 mm internal diameter; 200 mm length), four each for up-flow and down-flow leaching. Effluent was delivered continuously for 6, 8 and 35 days at high (32 mm·h-1), medium (16 mm·h-1), and low (2 mm·h-1) rates, respectively. At each flow rate, 9 pore volumes were collected. Leachates were analysed for pH, electrical conductivity (EC), nitrate and phosphate. Leachate pH from all soils was lower than the original effluent (6.4). Leachate EC varied between 0.5 and 0.9 dS·m-1 compared to the effluent EC of 0.84 dS· m-1. At high flow rate, the amount of nitrogen leached was similar from all soils. At low and medium rates, more nitrogen was leached from the coarser-textured SS and Cf than the finer-textured Ia and Se, at both flow directions. Flow direction had a greater effect on nitrogen leaching from finer- than coarser-textured soils. Phosphorus concentrations were higher than the original effluent at medium and high flow rates indicating that the soils were a source of phosphorus. At low flow rate, phosphorus concentrations were much lower than the original effluent, indicating soil retention. Phosphorus leaching was greater from coarser- than finer-textured soils in the up-flow columns, but the opposite occurred in the down-flow columns. 

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