TITLE:
Nitrogen movement in coarse-textured soils and its availability to maize (Zea mays L.) plant
AUTHORS:
John Mthandi, Fredrick C. Kahimba, Andrew Tarimo, Baanda A. Salim, Maxon Lowole
KEYWORDS:
N Concentration; Water Flux; Absorption Rate; Diffusion
JOURNAL NAME:
Agricultural Sciences,
Vol.4 No.8A,
August
19,
2013
ABSTRACT: Nitrogen (N) is the most important determinant nutrient for plant growth
and crop yield. Plants lacking N show stunted growth and yellowish leaves.
Plant growth and crop yield usually increase when N is added. However, too
much N leads to weak stems in grain crops (lodging) which result into low
yield. The aim of the study was to delineate changes of N concentration, its
direction of movement and its pattern of disposition in the soil as
influenced by amount of applied water and nitrogen so as to reduce N losses
and maximise its absorption by maize roots.The study was conducted during irrigation seasons of 2011
and 2012 at Nkango Irrigation Scheme, Malawi. The trials consisted of factorial
arrangement in a Randomised Complete Block Design (RCBD). The factors were
water and N and both were at four levels. The Triscan Sensor was used to
measure total N concentration at different vertical and lateral points. The study inferred
that changes of N concentration, its direction of movement and its pattern of
disposition in the soil are influenced by water flux and absorption rate of
plants roots due to gradient created by absorption. The study noted that when N
is in low supply, its movement towards maize roots is greatly influenced by diffusion.
The study concluded that to maximise N absorption by maize roots, the point
of N application should be at5 cmaway from the planting station to minimise N losses through drifting away from
the maize rooting zone.