Norflurazon and Simazine Losses in Surface Runoff Water from Flatwoods Citrus Production Areas

2007 ◽  
Vol 78 (5) ◽  
pp. 341-344 ◽  
Author(s):  
P. Chris Wilson ◽  
Brian Boman ◽  
Jane Ferguson Foos
2019 ◽  
Vol 65 (No. 3) ◽  
pp. 118-124
Author(s):  
Daniel Vejchar ◽  
Josef Vacek ◽  
David Hájek ◽  
Jiří Bradna ◽  
Pavel Kasal ◽  
...  

Regarding the increased surface runoff from production areas, wide-row crops grown on slopes are considered risk crops. By reducing the surface runoff, it is possible to mitigate the negative effects on both the soil and the plants and positively influence the subsequent production, e.g., after application of de-stoning before planting. During this research, the tied ridging method was applied during planting by a two-row planter in both central and tractor trail furrows in potato rows and on the slope of 8.8% compared to a control plot without this treatment. Rainfall and surface water runoff were monitored, and the crop yields were compared. During three monitored years, up to 86% of the runoff water in the central furrows was saved compared to the control, whereas it was up to 72% in the wider furrows for tractor travel. The total yield was increased on the treated area, however, the increase could not be statistically proven.


2007 ◽  
Vol 26 (2) ◽  
pp. 201 ◽  
Author(s):  
Patrick Chris Wilson ◽  
Brian Boman ◽  
Jane Ferguson Foos

1987 ◽  
Vol 19 (8) ◽  
pp. 75-86 ◽  
Author(s):  
S. P. Amaral

The technology of treatment through landfarming for oily wastes has been more and more often utilized in Brazil, always successfully. The definition, the processes which occur, as well as the factors which affect its performance are herein presented. Design parameters, such as location, ground characterization, dimensioning of the area of application, groundwater protection, drainage, treatment of surface runoff water and percolated liquid, among others, are presented. Operational procedures and quality monitoring of effluents and environment are also described. PETROBRÁS is already operating two landfarming systems and has several others in the design stage. We present data from these projects and report that oily waste degradation has been achieved in around six months. Finally, we expect to be contributing to the affirmation and development of this technology in our Country.


1992 ◽  
Vol 26 (7-8) ◽  
pp. 1851-1856 ◽  
Author(s):  
J. L. Lai ◽  
K. S. L. Lo

A mixing-based model for describing solute transfer to overland flow was developed. This model included a time-dependent mixing depth of the top layer and a complete-mixed surface runoff zone. In a series of laboratory experiments, runoff was passed at various velocities and depths over a medium bed. The media were saturated with uniform concentration of potassium chloride solution. Runoff water was sampled at the beginning and end of the flume and the potassium chloride concentration analyzed. Using this model, dimensionless ultimate mixing depth and dimensionless change rate of mixing depth from experimental data were investigated and implemented. The results showed that the Reynolds number and relative roughness are two important factors.


1994 ◽  
Vol 74 (1) ◽  
pp. 59-66 ◽  
Author(s):  
B. T. Bowman ◽  
G. J. Wall ◽  
D. J. King

The risk of surface-water contamination by herbicides is greatest following application to cropland when the active ingredients are at the maximum concentration and the soil is the most vulnerable to erosion following cultivation. This study determined the magnitude of surface runoff losses of herbicide and nutrients at, and subsequent to, application. The first of three weekly 10-min, 2.6-cm rainfalls were simulated on triplicated 1-m plots (a set) on which corn had been planted and the herbicide (metolachlor/atrazine, 1.5:1.0) and fertilizer (28% N at 123 kg ha−1) had just been applied. Identical simulations were applied to two other adjacent plot sets (protected from rainfall) 1 and 2 wk following herbicide application. Runoff (natural, simulated) was monitored for soil, nutrient and herbicide losses. Concentrations of total phosphorus in surface runoff water and nitrate N in field-filtered samples were not significantly influenced by the time of the rainfall simulation but exceeded provincial water-quality objectives. Atrazine and metolachlor runoff losses were greatest from simulated rainfall (about 5% loss) immediately following application. Subsequent simulated rainfall usually resulted in < 1% herbicide runoff losses. Herbicide concentrations in all plot runoff samples exceeded provincial drinking-water quality objectives. Since herbicide surface transport is primarily in the solution phase (not via association with soil particles), water-management conservation technologies are the key to retaining these chemicals on cropland. Key words: Herbicide, runoff, rainfall simulation, partitioning, water quality


2012 ◽  
Vol 16 (12) ◽  
pp. 4725-4735 ◽  
Author(s):  
M. Temesgen ◽  
S. Uhlenbrook ◽  
B. Simane ◽  
P. van der Zaag ◽  
Y. Mohamed ◽  
...  

Abstract. Adoption of soil conservation structures (SCS) has been low in high rainfall areas of Ethiopia mainly due to crop yield reduction, increased soil erosion following breaching of SCS, incompatibility with the tradition of cross plowing and water-logging behind SCS. A new type of conservation tillage (CT) involving contour plowing and the construction of invisible subsoil barriers using a modified Maresha winged "subsoiler" is suggested as a means to tackle these problems as an integral part of the SCS. We investigated the effect of integrating the CT with SCS on the surface runoff, water-logging, soil loss, crop yield and plowing convenience. The new approach of conservation tillage has been compared with traditional tillage (TT) on 5 farmers' fields in a high rainfall area in the upper Blue Nile (Abbay) river basin. Test crops were wheat [triticum vulgare] and tef [eragrostis tef]. Farmers found CT convenient to apply between SCS. Surface runoff appeared to be reduced under CT by 48 and 15%, for wheat and tef, respectively. As a result, CT reduced sediment yield by 51 and 9.5%, for wheat and tef, respectively. Significantly reduced water-logging was observed behind SCS in CT compared to TT. Grain yields of wheat and tef increased by 35 and 10%, respectively, although the differences were not statistically significant apparently due to high fertility variations among fields of participating farmers. Farmers who tested CT indicated that they will continue this practice in the future.


Plant Disease ◽  
2010 ◽  
Vol 94 (2) ◽  
pp. 244-249 ◽  
Author(s):  
G. Pietersen ◽  
E. Arrebola ◽  
J. H. J. Breytenbach ◽  
L. Korsten ◽  
H. F. le Roux ◽  
...  

Greening disease of citrus is a serious disease known in South Africa since the late 1920s. In South Africa, it is associated with infection by ‘Candidatus Liberibacter africanus’, a heat sensitive, phloem-limited, noncultured alpha-proteobacterium. Huanglongbing (HLB), a similar, but more devastating disease that was described initially from China but which now occurs in several citrus producing countries, is associated with a different Liberibacter species, ‘Ca. L. asiaticus’. A ‘Ca. L. africanus’ subspecies, ‘Ca. L. africanus subsp. capensis’, has been found only in South Africa infecting an indigenous Rutaceous species, Calodendrum capense (Cape Chestnut), in the Western Cape in 1995. The discovery of a new Liberibacter species in Brazil, ‘Ca. L. americanus’, and the spread of ‘Ca. L. asiaticus’ to a number of additional countries over the last few years prompted us to assess whether only ‘Ca. L. africanus’ is present in commercial citrus orchards in South Africa. Samples displaying greening or similar symptoms were collected from 249 citrus trees from 57 orchards distributed throughout the greening affected citrus production areas of South Africa. Multiplex polymerase chain reaction (PCR) was performed on DNA extracts to detect the known citrus Liberibacters. Amplicons were obtained from 197 samples. None of the samples yielded a 1,027-bp amplicon indicative of ‘Ca. L. americanus’ infection. The amplicons of 84 samples were sequenced, and all were identical to the cognate ‘Ca. L. africanus’ Nelspruit sequence in GenBank. No instance of ‘Ca. L. asiaticus’ or ‘Ca. L. africanus subsp. capensis’ sequence was found. Geographically representative samples that tested negative for Liberibacter also tested negative for phytoplasmas based on real-time PCR results. Based on the results of this survey, it is concluded that to date only ‘Ca. L. africanus’ is associated with citrus greening in commercial citrus in South Africa.


Soil Research ◽  
2006 ◽  
Vol 44 (6) ◽  
pp. 561 ◽  
Author(s):  
Danielle P. Oliver ◽  
Rai S. Kookana

Off-site movement of nutrients and sediment from furrow-irrigated agriculture has been a concern in the Ord River Irrigation Area, Western Australia. After consultation with growers, a range of management strategies were tested to assess the effectiveness of various practices to minimise off-site movement of nutrients during irrigation. This paper reports on the effectiveness of the additions of high molecular weight, anionic, polyacrylamide (PAM) to irrigation water to minimise off-site movement of phosphorus, nitrogen, carbon, and sediment. Surface runoff water quantity and quality from 4 separate irrigation bays, which contained 25 furrows per irrigation bay, was monitored over time for a single irrigation 35 days after sowing. Addition of PAM as a puck (cylindrical disc 55 mm diameter by 23 mm height) to the head of each irrigation furrow significantly (P < 0.001) decreased the average volume of surface runoff water leaving the irrigation bays by 54%, from 599 kL for the control irrigation bays to 277 kL for the PAM-treated irrigation bays. The addition of PAM also significantly (P < 0.001) decreased the average total suspended sediment load for the duration of the irrigation from 94.9 kg/ha for the control bays to 13.4 kg/ha for the PAM-treated irrigation bays. The concentrations of the different forms of N, P, and C measured in the runoff water were not significantly different between the 2 treatments. The amounts (g) of particulate (>0.45 µm) P and dissolved organic C were significantly (P < 0.01) less from the PAM-treated bays than from the control bays. There was a consistent trend for the addition of PAM to decrease the cumulative mass loss of all nutrients (N, P, and C) measured. However, significant decreases were only seen for particulate (>0.45 µm) P (by 94%), unfiltered (or total) N (by 56%), and unfiltered (or total) C (by 60%). This experiment demonstrated that the addition of PAM to irrigation waters has the potential to decrease the off-site movement of nutrients bound to colloidal material. However, in this study off-site movement of contaminants present in the ‘soluble’ (<0.45 µm) fraction is unlikely to be mitigated by the addition of PAM to irrigation water. The mode of application of PAM, however, may affect water infiltration and hence vertical movement of ‘soluble’ contaminants and requires further investigation to ensure that while off-site surface transport is being minimised, contamination of groundwater is not being increased. Other strategies to minimise off-site movement for contaminants in the dissolved phase also need investigation.


Author(s):  
E. S. Mohamed ◽  
Abdel-Aziz Belal ◽  
Mohamed Abu-hashim

Abstract Background Evaluation of surface runoff is an essential factor in the precision water and soil conservation management through their main extreme impacts on soil properties. The natural resource conservation service curve number model (NRCS-CN) model is used to estimate the magnitude of runoff. Collected topographic data is used to explain the effects of slope variation on water retention and surface runoff. Twenty-eight soil profiles are prepared in Nile delta, Egypt to cover different geomorphic units and hydrological soil groups in the study area. Results The results revealed that the highest value of surface runoff was distinguished close to the urban area and ranges between 40 and 50 mm. In urban areas, the surfaces are paved and there are no infiltration of water. Consequently, the runoff water directly flows to the storm channels. Runoff values ranging between 30 and 40 mm occurred at the north of the study area. The sloping surface and the nature of the clay soil contributed to generate more runoff than do lowland areas. Conclusion The study presented and tested the hydric runoff estimation based-model on the integrating of hydric balance parameters. The GIS tools analyze and compose these parameters to perform an indirect method for the quantity of water that results in direct surface runoff flow. This method helps to gain clear imaging of the surface runoff risks in the study area.


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