Effect of Prescribed Burning of Forest Litter on Total Soil Nitrogen

1962 ◽  
Vol 26 (2) ◽  
pp. 200-202 ◽  
Author(s):  
J. O. Klemmedson ◽  
A. M. Schultz ◽  
H. Jenny ◽  
H. H. Biswell
1967 ◽  
Vol 7 (24) ◽  
pp. 66 ◽  
Author(s):  
RJ Jones

Mixtures of some tropical legumes and Paspalum plicatulum (Michx) cv. Hartley, and stands of P. plicatulum were fertilized with urea at 100 and 200 lb nitrogen an acre a year, and were intermittently grazed by cattle over a period of four years. Soil analyses for organic carbon and for total soil nitrogen in the fourth year of the pasture phase revealed large treatment effects in three of the five replicates. These three replicates which were on a podsolic soil were lower in fertility than the remaining two on a latosolic soil. Soil nitrogen at the 0-3 inch depth in the high nitrogen treatment, and in two Phaseolus atropurpureus D.C. treatments was significantly higher than the control (P<0.05). Organic carbon at the 0-3 inch depth was significantly higher than the control (P<0.05) in the nitrogen treatments and in one of the P. atropurpureus treatments. For both soil nitrogen and organic carbon the Lotononis bainesii Bak. treatment did not differ from the control. There was no significant difference between treatments for soil nitrogen or organic carbon at the 3-6 inch depth though trends were similar to those at 0-3 inches. Organic carbon and nitrogen were closely correlated for all treatments at both depths, and there were no significant differences in the C : N ratio in any treatment. Yields of sorghum grown as a test crop after the pastures were significantly correlated with soil nitrogen values in the three low fertility replicates. A high correlation (r = +0.976) also existed between yields of nitrogen obtained in the pasture phase and test crop yields of nitrogen for all treatments except L. bainesii. Reasons for the apparent lack of improvement in soil nitrogen and carbon on the higher fertility replicates and for the poor test crop yields following L. bainesii are discussed.


2008 ◽  
Vol 54 (No. 10) ◽  
pp. 413-419 ◽  
Author(s):  
V. Vaněk ◽  
J. Balík ◽  
J. Šilha ◽  
J. Černý

Spatial variability of total soil nitrogen and sulphur content has been observed in two plots (I – 54 ha and II – 32 ha). Soil samples were taken from the topsoil in a regular grid, which was localised by GPS (individual sampling points were 80 m apart); subsequently total soil N and S contents were analysed. The average N content in plot I was 0.16%; in plot II it was 0.12%. The content of S in plots I and II was 0.09% and 0.08%, respectively. Spatial variability of total N differed in separate parts of the plots. A higher variability was recorded in plot I, where the coefficient of variation (<I>CV</I>) was 15.7%, whereas in plot II it was only 11.1%. However, sulphur showed only little variability, and thus its coefficient of variation was low (2.5 a 2.3% in plots I and II, respectively). A positive and mostly conclusive relationship has been observed between the N content of soil and the crop yield. This effect was more significant in plot II. The S content in soil showed no correlation with yield. Furthermore, positive correlations were observed between field altitude, soil moisture and crop yield in both plots.


1974 ◽  
Vol 14 (66) ◽  
pp. 49 ◽  
Author(s):  
CR Kleinig ◽  
JC Noble ◽  
AJ Rixon

Herbage yield, herbage nitrogen, and soil nitrogen accumulation were followed over a five-year period (1958-63) under irrigated annual and perennial pastures established initially with different clovergrass proportions. Species sown in the annual pasture treatments were subterranean clover (Trifolium subterraneum cv. Tallarook) and annual ryegrass (Lolium rigidum cv. Wimmera). Those used in the perennial mixtures were white clover (T. repens cv. Irrigation) and perennial ryegrass (L. perenne cv. Victorian). In the treatments sown to annual or perennial ryegrass only, nitrogenous fertilizer as urea was applied annually at four rates. Total soil nitrogen (mat + 0-91 cm of soil) after five years did not differ significantly for annual pasture and bare ground. In contrast, total soil nitrogen under all perennial pasture treatments, particularly those with a white clover component, was significantly greater than for bare soil (5365 cf. 4181 kg ha-1). Where white clover was sown, nitrogen accumulated at the rate of 258 kg ha-1 per annum compared with 101 kg ha-1 per annum under subterranean clover, the latter barely matching the accumulation rate under perennial ryegrass sown alone without applied nitrogen (105 kg N ha-1 p.a.). Nitrogen accumulation (soil plus mat) was related to both legume and non-legume nitrogen. Perennial pasture, particularly if white clover was present, generally outyielded annual pasture. The total yield of white clover over five years was 29,970 kg ha-1 compared with 11,614 kg ha-1 for subterranean clover. Annual and perennial ryegrasses showed similar yield responses to applied nitrogen. Irrespective of the rate of urea application, nitrogen recovery was low (21-23 per cent).


1980 ◽  
Vol 20 (103) ◽  
pp. 220 ◽  
Author(s):  
CL Tuohey ◽  
AD Robson

The effect of medic and non-medic pastures on grain yield and nitrogen content of wheat was studied over 15 seasons on a friable grey clay in the Wimmera. The effects of length and type of pasture ley on grain yield and nitrogen content were closely related to the effects of these treatments on total soil nitrogen. Grain yield was not increased in any season by increasing total soil nitrogen beyond 0.1 10%. The grain yield response to increased total soil nitrogen varied markedly with seasons and most of the variation could be accounted for by variation in November rainfall; grain yield response was greater in years of higher November rainfall. Grain nitrogen content increased with increasing total soil nitrogen over the range studied (0.078% to 0.1 28%). Seasonal variation in grain nitrogen response to total soil nitrogen was mainly associated with variation in September and November rainfall. Higher September rainfall increased the response and higher November rainfall decreased it. The decline in total soil nitrogen that occurred with cropping was strongly correlated with the level of total soil nitrogen before cropping.


Soil Research ◽  
1981 ◽  
Vol 19 (3) ◽  
pp. 239 ◽  
Author(s):  
ICR Holford

Changes in total and mineral nitrogen and organic carbon were measured over a nine year period in two contrasting soils of northern New South Wales after various durations of grazed lucerne, extended fallowing and continuous wheat growing. At least 2 1/2 years of lucerne ley were required to raise the total soil nitrogen above the original level on both soil types. For each year of lucerne growth the average increase (above the control treatments) in total soil nitrogen (0-15 cm) was equivalent to about 140 kg nitrogen ha-1 in the black earth and about 110 kg nitrogen ha-1 in the red-brown earth. Significantly higher levels of soil nitrogen were maintained after the lucerne treatments throughout the 9 years of measurement on the black earth and for 5 years on the red-brown earth. Lucerne had a much larger effect on nitrogen than on organic carbon, which was significantly increased only in the black earth. There were very large increases in mineral nitrogen (0-15 cm) in the first year of measurement after lucerne. Levels remained greater than they were originally for the first 4 years, and they were greater for 7 years in the black earth and 4 years in the red-brown earth following lucerne than following continuous wheat or extended fallow. The decline in mineral nitrogen during wheat cropping after lucerne was greatly increased by excessive rainfall (574 mm or more) during the fallow. Leaching was greater in the red-brown earth than in the black earth, and this explained occasional differences in nitrogen uptake by wheat between the two soil types. Some evidence suggested that under moderately moist conditions nitrogen mineralization from lucerne-fixed nitrogen was greater in the red-brown earth than in the black earth but under drier conditions it was less.


1967 ◽  
Vol 7 (29) ◽  
pp. 568 ◽  
Author(s):  
JV Mullaly ◽  
JB McPherson ◽  
AP Mann ◽  
DR Rooney

Total soil nitrogen increase in the surface six inches under sown pasture legume leys of up to ten years' duration at Dookie, Longerenong, Rutherglen, and Walpeup in the wheatgrowing areas of Victoria was linearly related to the length of pasture period. Annual increases in soil nitrogen were 0.00467, 0.00474, 0.00400, and 0.00142 per cent, respectively. Under non-legume pastures at Longerenong and Walpeup, annual increases in the surface six inches of 0.00292 and 0.00094 per cent nitrogen were obtained. The source of this nitrogen is not known.


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