Nitrogen release from decomposed residues of herbaceous legumes and their effect on maize growth and yield in low nitrogen soil
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Date
2013
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Publisher
Sokoine University of Agriculture
Abstract
This study was conducted at Sokoine University of Agriculture (SUA) located at
6°51'5"S and 37°39'26"E at 525 masl at the site with sandy clay soil pH 5.16 with
the overall objective of improving maize productivity through the use of leguminous
residues as source of nitrogen (N). Specifically the study aimed at determining the
mineralization pattern and total amount of N released from decomposition of legume
residues; to assess the effects of legume residues on maize growth and yield and to
evaluate the effects of legumes biomass applied on maize yield. The treatments used
were control (no legume residue and fertilizer application); application of N (Urea);
residues in form of velvets bean {Mucuna pruriens L.), dolichos {Lablab purpureus
L.) and sunhemp {Crotolaria ochroleuca G.). Maize variety “Staha” was used as a
test crop. Experiments conducted were laboratory mineralization experiment, screen
house and field experiments. These experiments were conducted between November
2011 and June 2012. Results showed that sunhemp had the highest N content of
2.77% followed by velvet bean and dolichos with 2.49 and 2.42%, respectively.
Total amount of N released over 16 incubation weeks differed significantly (P <
0.05) with the range of 151.22 pg kg'1. Leguminous biomass production was 15.13,
12.67 and 11.75 t ha'1 for velvet bean, dolichos and sunhemp, respectively. Maize
grain yield ranged from 1.02 for control to 3.96 t ha'1 with Urea application.
Sunhemp, velvet bean, and dolichos resulted in 3.69, 3.6 and 3.49 t ha'1,
respectively. As the incorporation of leguminous residues resulted into improvement
of soil physical characteristics such as texture, bulk density and moisture content, it
is recommended for use in mineral low N soils. This application will enhance poor
resources farmers to improve maize productivity.
Description
Dissertation
Keywords
Soil nitrogen, Herbaceous legumes, Nitrogen mineralization, Crops