Influence of Tillage, Antecedent Moisture, and Rainfall Timing on Atrazine Transport

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Gilbert C. Sigua ◽  
Allan R. Isensee ◽  
Alim. Sadeghi
Keyword(s):  
Pore Volume ◽  
Soil Cores ◽  
Leaching Rate ◽  
Laboratory Studies ◽  
Antecedent Moisture ◽  
No Till ◽  
Time Period ◽  
Soil Dryness ◽  
Intact Soil Cores ◽  
Intact Soil

Laboratory studies were conducted to determine the effect of rainfall timing and antecedent moisture on atrazine leaching through intact soil cores taken from no-till and conventional-till corn fields. Simulated rainfall was applied to no-till and conventional-till cores 1 to 14 d after atrazine application and, in a second study, one d after atrazine was applied to no-till and conventional-till cores at 1 to 800 kPa soil moisture. Increasing the lag time between atrazine application and rainfall from one to 14 d reduced the amount of atrazine leached by about 50% for both no-till and conventional-till soil cores. During the same time period, the amount of atrazine adsorbed to soil increased by about 30% for both tillages. Soil dryness (antecedent moisture) at the time of atrazine application had no effect on the amount of atrazine leached through conventional-till cores. However, leaching decreased in no-till cores as antecedent moisture decreased from 1 to 33 kPa; drying to 800 kPa had no further effect. The leaching rate of atrazine was much higher for the initial 0.5 pore volume than for the next 1.5 pore volume at all rainfall timing and antecedent moisture levels. This behavior is indicative of preferential transport.

scholarly journals Leaching of Cryptosporidium parvum Oocysts, Escherichia coli, and a Salmonella enterica Serovar Typhimurium Bacteriophage through Intact Soil Cores following Surface Application and Injection of Slurry

2011 ◽  
Vol 77 (22) ◽  
pp. 8129-8138 ◽  
Author(s):  
Anita Forslund ◽  
Bo Markussen ◽  
Lise Toenner-Klank ◽  
Tina B. Bech ◽  
Ole Stig Jacobsen ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Pore Volume ◽  
Relative Concentration ◽  
Weather Conditions ◽  
Soil Cores ◽  
Content Type ◽  
E Coli ◽  
Serovar Typhimurium ◽  
Intact Soil Cores ◽  
Intact Soil

ABSTRACTIncreasing amounts of livestock manure are being applied to agricultural soil, but it is unknown to what extent this may be associated with contamination of aquatic recipients and groundwater if microorganisms are transported through the soil under natural weather conditions. The objective of this study was therefore to evaluate how injection and surface application of pig slurry on intact sandy clay loam soil cores influenced the leaching ofSalmonella entericaserovar Typhimurium bacteriophage 28B,Escherichia coli, andCryptosporidium parvumoocysts. All three microbial tracers were detected in the leachate on day 1, and the highest relative concentration was detected on the fourth day (0.1 pore volume). Although the concentration of the phage 28B declined over time, the phage was still found in leachate at day 148.C. parvumoocysts and chloride had an additional rise in the relative concentration at a 0.5 pore volume, corresponding to the exchange of the total pore volume. The leaching ofE. coliwas delayed compared with that of the added microbial tracers, indicating a stronger attachment to slurry particles, butE. colicould be detected up to 3 months. Significantly enhanced leaching of phage 28B and oocysts by the injection method was seen, whereas leaching of the indigenousE. coliwas not affected by the application method. Preferential flow was the primary transport vehicle, and the diameter of the fractures in the intact soil cores facilitated transport of all sizes of microbial tracers under natural weather conditions.

scholarly journals Denitrification Rate and Its Potential to Predict Biogenic N2O Field Emissions in a Mediterranean Maize-Cropped Soil in Southern Italy

Land ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 97 ◽  
Author(s):  
Annachiara Forte ◽  
Angelo Fierro
Keyword(s):  
Pore Space ◽  
Denitrification Rate ◽  
Linear Functions ◽  
N2o Emissions ◽  
Soil Cores ◽  
High Soil ◽  
N2o Fluxes ◽  
Intact Soil Cores ◽  
Intact Soil ◽  
Soil Nitrates

The denitrification rate in C2H2-amended intact soil cores and soil N2O fluxes in closed static chambers were monitored in a Mediterranean irrigated maize-cropped field. The measurements were carried out during: (i) a standard fertilization management (SFM) activity and (ii) a manipulation experimental (ME) test on the effects of increased and reduced application rates of urea at the late fertilization. In the course of the SFM, the irrigations following early and late nitrogen fertilization led to pulses of denitrification rates (up to 1300 μg N2O-N m−2 h−1) and N2O fluxes (up to 320 μg N2O-N m−2 h−1), thanks to the combined action of high soil temperatures and not limiting nitrates and water filled pore space (WFPS). During the ME, high soil nitrates were noted in all the treatments in the first one month after the late fertilization, which promoted marked N-losses by microbial denitrification (from 500 to 1800 μg N2O-N m−2 h−1) every time the soil WFPS was not limiting. At similar maize yield responses to fertilizer treatments, this result suggested no competition for N between plant roots and soil microbial community and indicated a probable surplus of nitrogen fertilizer input at the investigated farm. Correlation and regression analyses (CRA) on the whole set of data showed significant relations between both the denitrification rates and the N2O fluxes with three soil physical-chemical parameters: nitrate concentration, WFPS and temperature. Specifically, the response functions of denitrification rate to soil nitrates, WFPS and temperature could be satisfactorily modelled according to simple Michaelis-Menten kinetic, exponential and linear functions, respectively. Furthermore, the CRA demonstrated a significant exponential relationship between N2O fluxes and denitrification and simple empirical functions to predict N2O emissions from the denitrification rate appeared more fitting (higher concordance correlation coefficient) than the predictive empirical algorithm based on soil nitrates, WFPS and temperature. In this regard, the empirically established relationships between the denitrification rate on intact soil cores under field conditions and the soil variables provided local-specific threshold values and coefficients which may effectively work to calibrate and adapt existing N2O process-based simulation models to the local pedo-climatic conditions.

Effects of Starch Encapsulation on Clomazone and Atrazine Movement in Soil and Clomazone Volatilization

Weed Science ◽  
1995 ◽  
Vol 43 (3) ◽  
pp. 445-453 ◽  
Author(s):  
Todd L. Mervosh ◽  
Edward W. Stoller ◽  
F. William Simmons ◽  
Timothy R. Ellsworth ◽  
Gerald K. Sims
Keyword(s):  
Unsaturated Flow ◽  
Soil Surface ◽  
Silty Clay ◽  
Silt Loam ◽  
Starch Granules ◽  
Soil Cores ◽  
Silty Clay Loam ◽  
Intact Soil Cores ◽  
Water Tension ◽  
Intact Soil

The effects of formulation on clomazone volatilization and transport through soil were studied. After 22 days of leaching under unsaturated flow in 49-cm long intact soil cores, greater clomazone movement was observed in Plainfield sand than in Cisne silt loam or Drummer silty clay loam soils. Soil clomazone concentrations resulting in injury to oats occurred throughout Plainfield soil cores but were restricted to the upper 14 cm of Cisne and Drummer soils. In addition, clomazone was detected in the leachate from Plainfield soil only. In a similar study with Plainfield sand cores, clomazone was less mobile than atrazine; encapsulation of the herbicides in starch granules did not affect clomazone movement but greatly decreased atrazine movement from the soil surface. Similarly, starch encapsulation did not affect bioavailability of clomazone but did reduce bioavailability of atrazine. In a laboratory study with continual air flow, volatilization of clomazone applied to the soil surface was reduced by encapsulation in starch and starch/clay granules. Clomazone volatilization was not affected by soil water content within a range of 33 to 1500 kPa water tension. Following soil saturation with water, clomazone volatilization from both liquid and granular formulations increased. Granule size appeared to have a greater impact than granule composition on clomazone volatilization.

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