TUGAS PUPUK dan PEMUPUKAN
“Potential use of green manure legume cover crops in smallholder
maize production systems in Limpopo province, South Africa “
Disusun oleh:
PIPIT WAHYUNI
115040213113005
PROGRAM
STUDI AGROEKOTEKNOLOGI
FAKULTAS
PERTANIAN
UNIVERSITAS
BRAWIJAYA
KEDIRI
2012
I.INTRODUCTION
Much of the smallholder farming sector
in Limpopo province of South Africa is located on infertile degraded soils,
with nitrogen being one of the predominantly deficient nutrient. The use of
green manure legume cover crops in combination with Nitrogen (N) fertilizers is
one option for improving N inputs into such farming systems.
A). Problems to be solved :(1) screen a number of green
manure legume cover crop species, mucuna (Mucuna pruriens); sunhemp (Crotalaria
juncea), lab-lab (Lablab purpureus); cowpea (Vigna unguiculata)
and butterfly pea (Clitoria ternatea) in order to determine their
suitability for the region and (2) to determine the effect of the green manure
and nitrogen fertilizer on maize yield.
B). Reason Writers journal chose Green manure :
Green manuring may also help maintain or build organic matter which
will in turn help improve the soil’s structure, pore size, water holding
capacity and inorganic fertilizer use efficiency (through increased cation
exchange capacity).
II.MATERIALS AND METHODS
This study was conducted in Thohoyandou, Limpopo province of South
Africa located approximately 22°35’14.0”S and 30°15’50.3”E.
Methods :
1) Green manure legume screening experiment 2) and Maize, N
fertilizer and green manure experiment.
C).The dose given in research :
Two control plots [(control (+N) and control (-N)].The treatments
imposed were mucuna, sunhemp, lablab,and a control with (75 kg N ha-1) or
without (0 kg N ha) N fertilizer. The N source used in the fertilizer treated
plots was Lime Ammonium Nitrate (LAN) (28% N). The 75 kg N ha was split applied
with 50 kg N ha-1 applied at planting and 25 kg N ha applied as top-dress.
Phosphorus was applied uniformly to all the plots at a rate of 50 kg ha -1 as super
grow (20.3%P). Maize (hybrid SNK 2147) was then planted at a spacing of 90 cm ×
25 cm (44444 plants per ha-1) approximately 2 weeks after incorporation of GML residues.
D). Measured variables and
measurement time
Variables : Green manure
above-ground and root biomass and N uptake.
Time : Winter
screening (2005-2006),Summer Screening(2006-2007),and 2006/2007 and 2007/2008
seasons.
III.RESULTS
E). Results obtained
Results obtained from the screening trials indicate that best GML
growth, biomass production and N accumulation are attained when the legumes are
planted during the summer season. The low temperatures during winter severely
limit the growth, biomass production and N accumulation of the legumes. Results
obtained by Odhiambo et al. (2009) from a two year study on green manure-maize rotation
system in Limpopo province showed that cowpea, mucuna, lablab, butterfly pea
and sunhemp treatments gave yield increases of 77, 85, 134, 125 and 103%,
respectively, above the control (-N) treatment.A combination of GML (mucuna,
sunhemp, lablab and cowpea) and 60 kg N ha-1 gave yield increment of between 23
to 118%. In terms of maize grain yield following green manure incorporation,
overall, legume treatments, with or without N fertilizers produced between 19
to 58% more grain yield than control
(-N).
IV.CONCLUTION
Use of green manure legumes in combination with N fertilizers has
the potential to increase maize yield in smallholder farms in Limpopo
province.
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