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MODELLING OF NITROGEN DYNAMICS UNDER SURFACE FERTIGATION

KrishiKosh

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Title MODELLING OF NITROGEN DYNAMICS UNDER SURFACE FERTIGATION
 
Creator SHIRSATH PARESH BHASKAR
 
Contributor A. K. Singh
 
Subject animal developmental stages, planting, soybeans, chillies, diseases, plant extracts, insecticides, oils, crops, productivity
 
Description T-8586
The present investigation was carried out to evaluate nitrogen fertilizer
application strategy, model the nitrogen dynamics under surface fertigation and
suggest appropriate design and management guidelines for nitrogen application in
surface fertigation. For this study, four field experiments were conducted during
2008 to 2010 on the research farm of Water Technology Centre, IARI, New Delhi.
Two of four experiments were carried out under basin irrigation system with and
without crop and the other two on non-cropped fields with furrow irrigation as well
as raised bed irrigation systems. Three surface fertigation strategies were considered
in the investigation, viz., fertigation during entire irrigation duration (EI), fertigation
during first half of irrigation duration (FH) and fertigation during second half of
irrigation duration (SH). The broadcasting method of fertilizer application was also
considered in the study. Surface irrigation systems were simulated using WinSRFR
model and Abbasi et al. (2003) model was used to quantify nitrogen movement as
influenced by different fertigation strategies and irrigation methods.
The results obtained indicated that the observed application efficiency in all
the four experiments was above 70%. The highest application efficiency of 89% was
obtained in furrow irrigation system. The highest low quarter Distribution
Uniformity (DUlq) was also obtained in the irrigation system. WinSRFR model over
predicted the values of irrigation performance indices. Nitrogen distribution patterns
after the fertigation event showed better distribution of nitrogen for fertilizer
application during entire irrigation followed by fertigation in first half and second
half. However, at the tail ends of basin irrigation slightly higher concentrations of
applied nitrogen was observed due to over irrigation. The best fertigation strategy in
terms of yield of the crop was “fertigation during the second half of irrigation
duration”. The highest DUlh (0.98) was obtained for fertigation during entire
irrigation duration under raised bed method while the lowest (0.77) was observed
under broadcasting with the third fertigation event of basin experiment with wheat
crop. The highest DUlq and CU were also obtained under fertigation during entire
irrigation duration. The study revealed that furrow irrigation system can be a
ii
promising method of surface irrigation with fertigation during entire irrigation
duration.
The combined model of Abbasi et al. (2003) under predicted the Fertilizer
Christiansen’s Distribution Uniformity (FCDU) for basin irrigation system whereas it
was over predicted for furrow as well as raised bed irrigation system. The model is
very well suited for simulating fertigation process especially for fertigation during
second half of irrigation (RMSE= 5.65 per cent), followed by fertigation during
entire irrigation duration (RMSE= 5.81 per cent), in furrow irrigation system. Results
indicated that combined model performed reasonably well with an average RMSE of
14.18 per cent.
Several “what-if” scenarios were generated using a combined model of
Abbasi et al. (2003a, b). Fertilizer Christensen’s Distribution Uniformity was used as
a criterion for arriving at the best option with non-erosive stream velocity as the
upper limiting value. The discharge rates of 1.5 lps/m and 2 lps/m were appropriate
with 0.01% field slope for surface fertigation.
 
Date 2016-12-15T11:17:45Z
2016-12-15T11:17:45Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/90271
 
Format application/pdf
 
Publisher IARI, WATER TECHNOLOGY CENTRE