Abstract:
Crop production is a complex system that integrates physical, chemical and biological
processes and is managed under increasing economic and ecological constraints. Maize is
one of a high valued crop in Ethiopia, especially in western regions of the country where it
is the dominant crop and is produced in a number of agro-ecologies in the region. Despite
tremendous yield potential, its productivity is constrained by blanket application of
inorganic nitrogen (N) fertilizers. This experiment was conducted during 2016 cropping
season at Bako, western Ethiopia with the objectives of validating and determine the
optimum nitrogen fertilizer rate for side dressing supported by normalized difference
vegetative index (NDVI) sensor for quality protein maize for efficient management of N to
optimize grain productivity of quality protein maize. The trials were laid out in a factorial
randomized complete block design with three rates of nitrogen fertilizer (0, 25 and 50 kg
N ha-1
) applied at planting and four rates of estimated N (19, 38, 56 and 75 kg N ha-1
)
applied as side dressing. The mean yield components of quality protein maize variety were
significantly affected by application of nitrogen rates. Significantly higher mean grain
yield of quality protein maize was obtained between 63 kg ha-1 N (25 kg ha-1
at planting
with 38 kg ha-1
side dressing) up to 100 kg ha-1 N. Significant differences were also
observed on measured NDVI and In-season estimation of yield (INSEY) at node initiation
(V4) growth stage of maize. Grain yield shows a higher correlation coefficients (0.78**)
with NDIV and INSEY at V4 growth stage of maize. The NDVI reading and calculated
INSEY at node elongation growth stage have strong correlation with grain yield (0.79**
and 0.75**). Overall, application of 25 kg N ha-1
fertilizer rates at planting with 38 kg N
ha-1 side dressing had better net benefit of ETB 53590 ha-1
. Therefore, application of 25 kg
N ha-1 at planting with 38 kg N ha-1
for side dressing is recommended for quality protein
maize variety in Bako area and similar agro-ecologies.
