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QUANTIFICATION AND PREDICTION OF WATER AND NITROGEN USE EFFICIENCIES UNDER LIMITED WATER AVAILABILITY

KrishiKosh

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Title QUANTIFICATION AND PREDICTION OF WATER AND NITROGEN USE EFFICIENCIES UNDER LIMITED WATER AVAILABILITY
M Sc
 
Creator SARATH CHANDRAN M. A.
 
Contributor Usha Kiran Chopra
 
Subject ---
 
Description t-8417
Quantification and prediction of the impacts of water and nitrogen (N) stresses
on water use efficiency (WUE) and nitrogen use efficiency (NUE) were carried out
based on two year field study with rabi wheat. Wheat (variety HD 2932) was grown on a
sandy loam soil of IARI, New Delhi research farm with four irrigations and four
nitrogen treatments to create differential water and nitrogen stresses in the field. The
irrigation treatments applied were zero (I0), 30% (I1), 60% (I2) and 100% (I3)
replenishment of profile moisture depletion to field capacity at each irrigation. The
nitrogen treatments were application of zero (N0), 30 (N1), 60 (N2) and 120 (N3) kgN
ha-1
. The water and nitrogen stresses developed in the field were quantified in terms of
stress factor for water (SFW) and stress factor for nitrogen (SFN). Based on the data
collected and analysis conducted on soil water content, plant biomass, percent N content,
N uptake and yield, WUE as the ratio of yield per actual evapotranspiration (kgha-1
mm
-1
) and nitrogen uptake use efficiency (NUE) were determined for each level of water
stress (SFW) and nitrogen stress (SFN). The influence of SFW and SFN on WUE, NUE
and yield were found to be significant at 1% level of significance. The interactive effects
of SFW and SFN on WUE, NUE and the associated percent change in yield show that
water stress of 0.18 SFW was beneficial for the improvement of WUE as well as of
NUE. The related yield decrease was about 3% which was non-significant at 1% level.
The results also indicated that under conditions of high water stress, decreased
application of N results in higher NUE. The reduction in yield linked with these stresses
was indeed much higher.
WUE was expressed as a function of SFW and SFN to predict the effects of
water and N stresses occurring simultaneously. Based on the first year data, linear
regression equations with WUE as dependent variable and SFW and SFN as
independent variables were developed. Similarly, predictive equations for NUE and
percent change in yield were also developed. All the three equations were validated with
the second year wheat data showed good accuracy of prediction for all the equations.
The impact of one stress factor at a given magnitude of second stress factor on WUE
57
was also predicted by developing linear regression equation at observed stress level of
the second factor. Similar equations predicting the effects of one stress at a fixed level of
second stress on NUE and percent change in yield were also developed. All these
relations showed very high values of coefficient of determination (R2
). An attempt was
made to develop a software program which predicted WUE by estimating crop yield
from HI and above ground biomass and AET from modified Penman-Monteith equation.
 
Date 2016-11-03T10:40:48Z
2016-11-03T10:40:48Z
2011
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/83594
 
Format application/pdf
 
Publisher IAri, AGRICULTURAL PHYSICS