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Response of fodder maize (Zea mays L.)
to levels of nitrogen, zinc and seed rate under
temperate conditions
Syed Sheraz Mahdi
Dr. Badrul Hasan
Ph.D
2011
Fodder maize, Nitrogen, Seed rate, Zinc
ABSTRACT
A field experiment was conducted at Research Farm, Division of Agronomy, Sher-eKashmir University of Agricultural Sciences and Technology of Kashmir during Kharif 2009
and 2010 on silty clay loam soil, low in available nitrogen and zinc, medium in available
phosphorus and potassium with neutral pH, to study the response of fodder maize to levels of
nitrogen, seed rate and zinc. The experiment was laid out in Randomized Block Design with
three nitrogen levels (N1-60 kg ha-1, N2-90 kg ha-1 and N3-120 kg ha-1), three seed rates (S1-40 kg
ha-1, S2-60 kg ha-1 and S3-80 kg ha-1) and two zinc levels (Z1-0 kg ha-1 and Z2-10 kg ha-1),
replicated thrice. The plots were given uniform recommended dose of phosphorus and potassium
@ of 60 and 30 kg P2O5 and K2O ha-1, respectively, during both seasons.
Application of 120 kg N ha-1 significantly increased the plant height, leaf area index,
dry matter production, chlorophyll content and number of functional leaves plant-1 at different
crop growth periods of fodder maize during both years of experimentation. Stem diameter
showed significant and consistent increase, whereas leaf stem ratio recorded consistent decrease
with increase in nitrogen application from 60 to 120 kg ha-1. Both green and dry fodder yield as
well as mean dry fodder yield over two years, nitrogen and zinc content and their uptake
recorded significant increase with increase in levels of nitrogen up to 120 kg ha-1. Crude protein
content showed significant increase, whereas, crude fiber content showed significant and
consistent decrease up to 120 kg N ha-1 and crude fiber recorded with 60 and 90 kg N ha-1, being
statistically at par, was significantly higher than 120 kg N ha-1 during both years. Calcium
content recorded with 90 and 120 kg N ha-1, being at par, was significantly higher than 60 kg N
ha-1, whereas, ash content increased significantly and consistently with increase in nitrogen from
60 to 120 kg N ha-1.
At different crop growth stages, seed rate 80 and 60 kg ha-1, at par with one another
significantly increased plant height and dry matter, whereas, Leaf area index increased
significantly and consistently up to 80 kg ha-1. Chlorophyll content and number of
functional leaves plant-1 remained unaffected by different seed rates during both years of
experimentation. Stem diameter recorded significant and consistent decrease with increase in
seed rate up to 80 kg ha-1, whereas leaf stem ratio decreased significantly with increase in seed
rate from 40 to 60 kg ha-1. Increased seed rate significantly increased green fodder yield,
whereas, dry fodder yield and its mean yield over two years recorded with 60 and 80 kg seed rate
ha-1 being at par, was significantly higher than 40 kg seed rate ha-1. Nitrogen and zinc content in
the plant remained unaffected by different seed rates, however, nitrogen and zinc uptake
recorded with 60 and 80 kg seed rate ha-1 were similar but statistically higher over 40 kg seed
rate ha-1. Crude protein content was unaffected by different seed rates, whereas its yield recorded
with 60 and 80 kg seed rate ha-1was statistically higher over 40 kg seed rate ha-1. Crude fiber
content decreased significantly and consistently with increase in seed rates from 40 to 60 kg ha-1,
whereas, its yield recorded with 40 and 60 kg seed rate ha -1 was statistically similar but
significantly lower over 80 kg seed rate ha-1. Calcium content remained unaffected with different
seed rates, whereas ash content of fodder decreased significantly with increase in seed rate from
40 to 80 kg ha-1.
Zinc application at 10 kg ha-1 significantly increased the plant height, leaf area index,
dry matter production, chlorophyll content and number of functional leaves plant-1 over no zinc
application at all crop growth stages. Stem diameter, leaf-stem ratio, green and dry fodder yield
also increased significantly with zinc application @ 10 kg ha-1, during both years of study.
Significantly higher nitrogen and zinc content; their uptake, crude protein content, its yield,
calcium and ash content was recorded with application of zinc than no zinc application, whereas
crude fiber content and yield was significantly lower at 10 kg Zn ha-1.
Available nitrogen in the soil after crop harvest during both years ranged from 261.6
to 262.6 and 261.3 to 262.1 kg ha-1, respectively, which was lower than initial nitrogen content
of 265.31 and 265.8 kg ha-1, thus available nitrogen balance in soil after crop harvests was
negative. Available zinc in the soil after crop harvest during 2009 and 2010 ranged from 0.53 to
0.58 and 0.53 to 0.59 ppm, respectively as against initial zinc balance of 0.51 ppm during 2009
and 0.54 ppm during 2010. As such there was a positive balance of zinc in the soil after crop
harvest in two years.
Highest gross and net returns were realized with treatment combination N120S80Z10,
whereas, benefit-cost ratio was highest with treatment combination N120S60Z10 and N120S80Z10
during both years.
Thus, the results of the study lead to conclusion that for realizing higher yield and
quality of fodder maize under temperate conditions, the nutrient management must centre around
120 kg N and 10 kg Zn ha-1 with a seed rate of 80 kg ha-1, along with recommended dose of
phosphorus (60 kg ha-1) and potassium (30 kg ha-1).