CHANGES IN NATURAL 15N ABUNDANCE OF SOILS ASSOCIATED WITH TILLAGE PRACTICES

1984 ◽  
Vol 64 (3) ◽  
pp. 345-354 ◽  
Author(s):  
F. SELLES ◽  
R. E. KARAMANOS ◽  
K. E. BOWREN
Keyword(s):  
Particle Size ◽  
Conventional Tillage ◽  
Soil N ◽  
Zero Tillage ◽  
Total N ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Tillage Practices ◽  
Total Soil ◽  
Total Soil N

The objective of this study was to determine changes in N dynamics in an Orthic Black Chernozem as a result of two tillage practices (conventional and zero tillage) using the variations in the natural 15N abundance of different soil-N fractions. After 14 yr, no significant differences in isotope composition of total soil-N between the two tillage practices could be found. However, changes were detected in the natural 15N abundance of the acid-hydrolyzable N and various organo-mineral size fractions which led to useful comparisons of the nature of N under the two systems. The N-content of the hydrolyzable-N fraction was similar at the 0- to 4- and 8- to 16-cm depth under both tillage practices, while it was significantly different at the 4- to 8-cm depth. The δa15N of this fraction was consistently higher than that of total soil N at all depths only under zero tillage. This was associated with the presence of more labile N compounds under zero tillage. No differences in the isotopic composition of the organomineral size fractions were found at the 0- to 4-cm depth. At the 4- to 8- and 8- to 16-cm depths, the δa15N values of the finer particle size fractions were higher under zero tillage than under conventional tillage. This indicates a more labile nature of the N associated with these size fractions under zero tillage. Key words: δa15N, conventional tillage, zero tillage, total N, acid-hydrolyzable fraction, particle size fractions

DISTRIBUTION OF CARBON, NITROGEN, SULPHUR AND PHOSPHORUS IN PARTICLE-SIZE SEPARATES FROM GLEYSOLIC SOILS

1980 ◽  
Vol 60 (4) ◽  
pp. 783-786 ◽  
Author(s):  
A. A. HINDS ◽  
L. E. LOWE
Keyword(s):  
Particle Size ◽  
Soil Carbon ◽  
Organic P ◽  
Soil N ◽  
Dispersion Method ◽  
Ultrasonic Dispersion ◽  
Soil Material ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Fine Clay

Levels of C, N, S and organic P (Po) were determined in fine, medium and coarse clay- and silt-size separates obtained from five Gleysolic soils by an ultrasonic dispersion method. Contents of C, N, S and Po increased with decreasing particle size, with average C values increasing from 3.7% in the silt to 10.1% in fine clay fractions. The corresponding increases for N, S and Po were 0.26–1.17%, 0.037–0.178% and 0.043–0.172%, respectively. C/N and C/S ratios decreased with decreasing particle size, indicating a relative enrichment of N and S in the finer particle-size fractions. N/S showed little variation with particle size, while C/Po ratios were erratic. The three clay fractions accounted on average for 31.3% of the soil material, and for 39.1% of soil carbon. In contrast, the clay fractions together accounted on average for 52–59% of soil N, S and Po.

scholarly journals Nitrification potential, dehydrogenase activity and microbial biomass in an argiudol soil cultivated with wheat under two tillering methods

2003 ◽  
Vol 1 (1) ◽  
pp. 111 ◽  
Author(s):  
G. Diosma ◽  
S.I. Golik ◽  
H.O. Chidichimo ◽  
P.A. Balatti
Keyword(s):  
Dehydrogenase Activity ◽  
Conventional Tillage ◽  
N Fertilization ◽  
Management Systems ◽  
Soil N ◽  
Zero Tillage ◽  
Tillage Systems ◽  
Total N ◽  
Soil N Mineralization ◽  
Conventional Management

The purpose of this work was to analyze the dynamics of soil biomass and its activity in a soil fertilized with N andcultivated under conventional or zero tillage systems. The soil under conventional tillage had larger biomass than underzero tillage but, in this latter condition, it was further increased by the N-fertilization. Dehydrogenase activity inthe soil was identical under both management systems suggesting similar levels of activity. In addition, fertilizationdid not modify the nitrogen mineralization capacity of the soil. Only the addition of calcareous NH4NO3, a fertilizerthat releases nitrogen much faster than urea, resulted in the immobilization of nitrogen during wheat tillering, whereasurea did not alter soil N mineralization. The lack of a significant biomass response to tilling practices was reflectedby the wheat biomass and grain yield, that was the same under both tilling systems. Only the total N content of wheatwas higher under zero tillage than under conventional management, although this did not result in an increment ingrain yield.

Variations in natural enrichment of 15N in the profiles of some Australian pasture soils

Soil Research ◽  
1984 ◽  
Vol 22 (2) ◽  
pp. 155 ◽  
Author(s):  
SF Ledgard ◽  
JR Freney ◽  
JR Simpson
Keyword(s):  
Soil Depth ◽  
Trifolium Subterraneum ◽  
Parent Material ◽  
Organic N ◽  
Soil N ◽  
Total N ◽  
Total Soil ◽  
Lateral Variations ◽  
Total Soil N ◽  
Natural Enrichment

Variability in the natural enrichment of 15N in total nitrogen (N) and several N fractions was examined for profiles of pasture soils differing in parent material and period under Trifolium subterraneum. The natural enrichment of 15N in the total N of surface soils (0-5 cm) within a 400 km2 catchment ranged from 2.55 to 6.79�(expressed as �15N with respect to atmospheric N2). There was no relationship with parent material, period under T. subterraneum or concentration of total N in the soil. In one soil, lateral variations in �15N over a 12 m2 grid were within the range of 5.01 to 7.95�. The �15N of total soil N always increased with depth in the soil profiles. This was associated with an increase in the stable clay-sized humus fraction, which had a higher �15N than the less humified organic N in sand and silt-sized fractions. One soil was separated into four depth layers in which �15N in the inorganic N, mineralizable N, plant-extractable N and total soil N were determined. The first three parameters all had lower �15N values than the total soil N. The �15N of total N increased with soil depth, whereas there was no change with depth in the other three parameters.

THE MINERALIZATION OF NITROGEN AND SULPHUR FROM PARTICLE-SIZE SEPARATES OF GLEYSOLIC SOILS

1983 ◽  
Vol 63 (4) ◽  
pp. 761-765 ◽  
Author(s):  
L. E. LOWE ◽  
A. A. HINDS
Keyword(s):  
Particle Size ◽  
Nitrogen Mineralization ◽  
Aerobic Incubation ◽  
Mineral N ◽  
Total N ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Sulphur Mineralization ◽  
Organic Fractions ◽  
Key Words Nitrogen

An aerobic incubation procedure was used to evaluate the susceptibility to mineralization of N and S in five Gleysolic soils and their particle-size fractions (2–50 μm, 1–2 μm, 0.2–1 μm and < 0.2μm). During an 8-wk incubation, the release of mineral N and S increased with decreasing particle size. The N:S ratio of the mineralization products was generally narrower than that of the starting materials. Total N mineralized from size fractions after 8 wk accounted for 4.5–25.4% of fraction N. For S the corresponding range was 2.7–43.3% of fraction S. The proportions of N and S released after 8 weeks showed no consistent relationship to particle size, although, in a number of cases, the proportions of N and S released were greater for the finer size fractions. It was concluded that complexing of organic fractions with clays did not, in itself, confer increased resistence to mineralization of N and S. Key words: Nitrogen mineralization, sulphur mineralization, particle-size separates, Gleysolic soils

Effect of tillage and crop establishment methods on yield and economics of cotton

2018 ◽  
Vol 5 (01) ◽  
Author(s):  
ANIL KHIPPAL ◽  
KAMINI KUMARI S. Bhadauria ◽  
JASBIR SINGH
Keyword(s):  
Conventional Tillage ◽  
Variable Cost ◽  
Cost Ratio ◽  
Zero Tillage ◽  
Benefit Cost Ratio ◽  
Tillage Practices ◽  
Plant Stand ◽  
Method Of Planting ◽  
Benefit Cost ◽  
Very High

In Haryana (India) cotton is generally sown with conventional tillage practices witnesses poor germination and plant establishment. Poor plant stand is attributed by burning of emerging plants due to very high temperature at the time of planting, which is further worsen by crust formation due to pre-monsoon showers. Keeping these points in view, an experiment was conducted with farmers' participatory research mode in village Hajwana of Kaithal district. Cotton sown with zero tillage technique resulted in approximately five percent higher yield i.e. 136.3 kg ha-1 over conventional tillage. Mean returns over variable cost of all the three years were 10.8 percent i.e. Rs. 11794 ha-1 more in zero tillage over conventional tillage. Benefit: cost ratio were 3.86, 3.86 and 4.61 in conventional method of planting, bed planting and zero tillage technique, respectively. Zero tillage planting of cotton reduced fuel consumption by 93.4 % and 91.7 % compared to bed planting and conventional planting respectively.

Digital soil mapping of compositional particle-size fractions using proximal and remotely sensed ancillary data

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. WB201-WB211 ◽  
Author(s):  
S. Buchanan ◽  
J. Triantafilis ◽  
I. O. A. Odeh ◽  
R. Subansinghe
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Soil Mapping ◽  
Additive Models ◽  
Digital Soil Mapping ◽  
Unbiased Estimation ◽  
Ancillary Data ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Log Ratio

The soil particle-size fractions (PSFs) are one of the most important attributes to influence soil physical (e.g., soil hydraulic properties) and chemical (e.g., cation exchange) processes. There is an increasing need, therefore, for high-resolution digital prediction of PSFs to improve our ability to manage agricultural land. Consequently, use of ancillary data to make cheaper high-resolution predictions of soil properties is becoming popular. This approach is known as “digital soil mapping.” However, most commonly employed techniques (e.g., multiple linear regression or MLR) do not consider the special requirements of a regionalized composition, namely PSF; (1) should be nonnegative (2) should sum to a constant at each location, and (3) estimation should be constrained to produce an unbiased estimation, to avoid false interpretation. Previous studies have shown that the use of the additive log-ratio transformation (ALR) is an appropriate technique to meet the requirements of a composition. In this study, we investigated the use of ancillary data (i.e., electromagnetic (EM), gamma-ray spectrometry, Landsat TM, and a digital elevation model to predict soil PSF using MLR and generalized additive models (GAM) in a standard form and with an ALR transformation applied to the optimal method (GAM-ALR). The results show that the use of ancillary data improved prediction precision by around 30% for clay, 30% for sand, and 7% for silt for all techniques (MLR, GAM, and GAM-ALR) when compared to ordinary kriging. However, the ALR technique had the advantage of adhering to the special requirements of a composition, with all predicted values nonnegative and PSFs summing to unity at each prediction point and giving more accurate textural prediction.

CHARACTERIZATION OF PARTICLE SIZE FRACTIONS OF PEAT. AN INTEGRATED BIOLOGICAL, CHEMICAL, AND SPECTROSCOPIC APPROACH

Soil Science ◽  
1992 ◽  
Vol 153 (5) ◽  
pp. 382-396 ◽  
Author(s):  
B O NORDEN ◽  
ELISABET BOHLIN ◽  
MATS NILSSON ◽  
ÅSA ALBANO ◽  
CHRISTINA RÖCKNER
Keyword(s):  
Particle Size ◽  
Size Fractions ◽  
Particle Size Fractions
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