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Shekhar Shashank Mailapalli Damodhara Rao Raghuwanshi Narendra Singh Das Bhabani Sankar 《Paddy and Water Environment》2020,18(1):73-85
Paddy and Water Environment - Alternate wetting and drying (AWD) irrigation practice in paddy cultivation requires a safe soil moisture stress level in the root zone for which irrigation water... 相似文献
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Damodhara R. Mailapalli N. S. Raghuwanshi R. Singh G. H. Schmitz F. Lennartz 《Irrigation Science》2008,26(2):161-168
TDR was used to estimate furrow infiltration, which is a key component in furrow irrigation system design and management.
Furrow irrigation experiments were conducted on bare and cropped fields consisting of three 40 m long parabolic shaped furrows
spaced at 0.8 m on a slope of 0.5%. The centre furrow was taken as the study furrow and the other two provided a buffer to
the centre furrow. Altogether, 22 irrigations were conducted during 2004 and 2005 with inflow rates ranging from 0.1 to 0.7 l s−1. TDR probes were installed vertically around the centre furrow at four locations 0.5 (S1), 13 (S2), 26 (S3) and 39.5 m (S4) from the inlet end. The S1 and S3 locations had four TDR probes installed at 0.15, 0.30, 0.45 and 0.60 m depths whereas the S2 and S4 locations had two probes each at 0.15 and 0.30 m depths. Soil moisture data collected at 5-min intervals were used to determine
the average soil moisture content of the field. The change in moisture content was used to estimate the furrow infiltration
which was compared with that measured using an inflow–outflow (IO) method. The performance of the TDR method was studied by
calculating the absolute prediction error (APE), root mean square error (RMSE) and index of agreement (I
a). It was found that the TDR-method estimated furrow infiltration well for higher inflow rates and during the initial stages
of irrigation. APE decreased and I
a increased with increase in flow rate for both bare and cropped conditions. The APE and RMSE were found to be larger for a
cropped field than the bare field when irrigated at the same inflow rate. The accuracy of the TDR-method for estimating total
infiltration was improved by using the average field moisture content of 30 or 45 min after the recession phase ceased. These
results indicate that TDR can be used to estimate in situ infiltration under furrow irrigation. 相似文献
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Development of control release urea fertilizer model for water and nitrogen movement in flooded rice
Paddy and Water Environment - Application of control release fertilizer in rice cultivation is a smart way to reduce the environmental nitrogen contamination and enhance the nitrogen use... 相似文献
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Irrigation-induced erosion in furrow irrigation causes loss of fertile soil and water quality degradation. Hence, quantification
of irrigation-induced erosion is essential for efficient management of furrow irrigation. In this study, sediment transport
was studied under bare and cropped field conditions for a furrow plot consisting of three parabolic shaped furrows of 40 m
long and 0.5% slope. The inflow rates of 0.2, 0.3, 0.4 and 0.5 L s−1; and 0.3, 0.4, 0.5, 0.6 and 0.7 L s−1 were used for bare and cropped field conditions, respectively. The furrow cross section measured at every 5 m distance from
the head end (before and after the irrigation event) was used to study the erosion pattern (erosion/deposition) along the
furrow. The runoff collected at regular intervals of 10 min was used to study the sediment load. The total sediment export
for an irrigation event was estimated using furrow cross-section data (FCD) and the sediment rate data (SRD), and compared
with the total sediments collected at the tail end. For both bare and cropped conditions, soil erosion took place at the head
and tail ends (free drain system), while the deposition occurred at the middle. The sediment transport increased initially
and slightly decreased with time. A power relationship was obtained between the total sediment export and the inflow rate
for bare furrow condition, whereas a linear relationship between these parameters was obtained for cropped field condition.
The relative percentage errors suggested that both SRD and FCD methods can be used to estimate total sediment export from
the field. The analysis (PSD) of the total sediments revealed that the geometric mean diameter of the sediment particle was
0.18 and 0.20 mm for bare and cropped field conditions, respectively. 相似文献
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Farming practices, including tillage, cover cropping and residue management can have profound effects on the efficiency of irrigation practices. The effects of three field management practices (FMPs) standard tillage and winter-fallow (ST), standard tillage and winter-cover crop (STCC), and no-till and winter-fallow (NT) and two field lengths (122 and 366 m) on runoff and export of dissolved organic carbon (DOC) were investigated in a furrow-irrigated cropping system over two years. The residue cover was 40, 32 and 11% in 2007, and 58, 61 and 11% in 2008 for STCC, NT and ST, respectively. Furrow irrigation experiments were conducted prior to crop planting following the cover crop. The inflow was kept constant across all treatments, and infiltration and runoff were estimated using a volume balance model (VBM). The DOC concentration tended to increase with increasing field length, but did not differ among the FMPs. A threefold increase in field length increased infiltration by 40%, and decreased runoff by 60-90% and DOC export by 65-83%. In both years, infiltration was highest in STCC. In NT, infiltration was lowest in 2007, which was likely due to soil sealing, and intermediate among the three FMPs in 2008 perhaps due to the increase in residue cover in the second year. The DOC budget analysis showed that fields and FMPs acted as DOC sinks exporting less DOC than was applied in the irrigation water. The results suggest that longer furrows and STCC were greater DOC sinks compared to ST and shorter field practices. The VBM, as applied in this study to estimate infiltration and runoff, could be used to predict optimal field length to minimize runoff and promote DOC adsorption to soil within the constraints of water quality and availability and soil conditions. 相似文献
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