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to 48 days after sowing “DAS”). The applied irrigation water (m3 ha-1) in each irrigation
treatment every season was quantified by using water counter apparatus that attached with
the irrigation machine. The management of each irrigation treatment at each development
stage of maize plants over both seasons (2015 and 2016) is shown in Table3. Nitrogen and
phosphorus fertilizers were applied to maize as recommended by the Egyptian Ministry of
Agriculture (285 kg N ha-1; urea 46.5% N and 357 kg superphosphate ha-1 (15.5% P2O5).
Foliar spray treatments comprising SA at 0.5 mmol, MLE at 1:30 (w/v) ratio and their
combinations, as well as tap water as a control were applied twice, at 30 and 45 DAS, (at
2.5-3.0 L plot-1; i.e. 25 and 30 ml, respectively for each plant) in both seasons. The
experiment was laid out in a randomized complete block design (RCBD) using split-plot
arrangements. Two furrow irrigation treatments (full and deficit irrigation) and four spray
treatments (tap water, MLE, SA, and MLE+SA) were assigned as main plots and sub-plots,
respectively.
Determination of growth attributes
Five plant samples were randomly collected from each plot at 30 and 48 DAS (before and
after spray treatments, respectively), then divided into roots, leaf blades and aerial non-leaf
blades to estimate growth parameters including root, shoot and plant biomass (determined at
70 °C for 72 h), total leaf area (determined by leaf discs), as well as relative growth rate
(RGR) and net assimilation rate (NAR) that were calculated according to Salisbury (1996)
as follows:
RGR (mg g-1 day-1) = (In m2 – In m1) / (t2-t1)
NAR (mg cm-2 day-1) = (m2 – m1)/ (t2-t1) x (In LA2 – In LA1)/ (LA2 – LA1)
Where m1 and LA1 refer to total plant biomass and leaf area at 30 DAS (t1), respectively;
and m2 and LA2 refer to total plant biomass and leaf area at 48 DAS (t2), respectively. Other
growth parameters including plant height and number of leaves were estimated at 48 DAS.
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