Design of Demonstration Plots and Their Equipment
for Measurement of Runoff and Sediment
Quantification
WAN ABDULLAH, W.Y., S. ABDUL KAHAR & A. AINI
HAYATI
(Ful Text-pdf-3.28MB)
Six runoff plots are constructed at MARDI
Agrotechnology Park, Cameron Highlands measuring 2.5 by 10.0 m
to measure runoff and sediment from a 5% slope. To each plot
was fixed a small 3-l tipping bucket, constructed using an
acrylic sheet inserted into an acrylic box. The bucket was
connected to a plastic stilling basin before attaching it to
the runoff plot. The size of the tipping bucket was determined
based on the desired area of the plot, maximum rainfall
intensity and expected runoff and also the diameter of the
runoff water conveyor pipe which in turn will depend on the
head of water. The bucket constructed could accommodate a
maximum flow of 19.5-l/min in the area with a tipping interval
of 9.2 sec per cycle.
Effect of Some Organic Carboxylic Acids on
Nitrification of Urea in a Subtropical Soil
RAJESH KUMAR, ANUPAMA & BALRAJ S.
PARMAR
(Full Text-pdf-4.45MB)
Nitrification inhibition of soil-N and applied
fertilizer N is desirable as the accumulation of nitrates in
soils in excess of plant needs, leads to enhanced N losses and
reduced fertilizer N-use efficiency. The effect of twenty-two
different organic carboxylic acids, representing aliphatic (C1
to C18), di-, chloroacetic, hippuric, benzoic and heterocyclic
(furoic, nicotinic and isonicotinic), on nitrification in a
semi-arid subtropical sandy loam (Typic Ustrochrepts) soil in
a laboratory incubation experiment is reported. The compounds
were screened at 10% of applied-N dose and incubated for a
period of 21 days at 300C, maintaining 50% of the water
holding capacity of the soil. Most of the test acids were
found to be mild inhibitors of nitrification. Nitrification
inhibition was the maximum (31.4%) in nicotinic acid treated
soil followed by isonicotinic, furoic, palmitic, and stearic
acid treated soils (26.6-27.8%). Based on four indicators of
inhibitor effectiveness, namely, concentration of ammonium-N
and nitrate-N, and total mineral N, nicotinic acid showed the
highest relative efficiency among all the test acids. A
quantitative structure activity relationship (QSAR) model
based on nitrification inhibitory activity [Arc sine (% NI)]
and various physico-chemical substituent parameters for
hydrophobic and steric properties has been developed using
multiple linear regression (MLR) analysis technique.
3-D Direct Solar Radiation Regime of Maize (Zea
mays L.)
C. B. S. TEH
(Full Text-pdf-4.36MB)
The main objective of this study was to develop
and test a 3-D solar radiation model for maize (Zea mays L.).
the model was developed by dividing the canopy space of maize
into a network of 3-D cuboids, and for each cuboid, three
properties were determined : 1) leaf area, 2) leaf
orientation, and 3) mean traveling distance of a solar beam.
These three properties were determined using the polygon
clipping and ray-tracing algorithm. Then Beer’s law was used
to determine the solar irradiance for the given cuboid. A
maize field experiment (18 x 18 m, planting density of 6
plants m-2) was also conducted to test the model’s accuracy.
The canopy architecture of 3-6 maize plants was measured
weekly starting 27 days from sowing. Solar irradiance was also
measured diurnally. The model was shown to be accurate (mean
error of 6%) when applied to all growing stages of maize, with
no overall tendency to either over or underestimate the
fraction of captured solar radiation. The simulated 3-D plant
radiation regime showed that the diurnal changes in the
spatial plant-radiation profile for sparse canopies (leaf area
index of 0.9) was more varied than that for almost closed
canopies ( leaf area index of 2) which was more uniform and
less diverse.
Mapping the Production and Retention of Cotton
Fruit as Influenced by Potassium Nutrition on Field Grown
Cotton
PERVEZ, H., M ASHRAF & M. I. MAKHDUM
(Full Text-pdf-8.26MB)
A field experiment was conducted to assess the
effectiveness of fruiting positions along sympodia under
varying levels and sources of potassium fertilizer on field
grown cotton under an arid environment. Treatments consisted
of four rates of potassium (0, 62.5, 125.0, 250.0 kg K ha-1)
and two sources of potassium (K2SO4 and KCL). Cotton cultivar
NIAB-Karishma (Gossypium hirsutum L.) was used as test crop.
Plant mapping data showed that total nmber of fruiting
positions, number of intact fruit on sympodia / monopodial and
percent of bolls per position on sympodia differed greatly due
to different doses of potassium fertilizer. The percentage of
fruit retention was markedly improved due to increasing doses
of K-fertilizer compared to K-unfertilized treatment. The
percentage survival of harvestable bolls for the five first
positions along sympodia at the end of season was 29, 26, 18,
13 and 8, respectively. Potassium fertilization stimulated
cotton crop in lengthening sympodial branches and retaining
more fruit on the three first positions and also at the bottom
of the plant during the early reproductive phase. The fruiting
pattern was 2 to 3 and 6 to 7 days vertical and horizontal
fruiting intervals, respectively.
An Assessment of Paddy Soil Degradation and Its
Impact on Sustainable Rice Production
AMINUDDIN, B. Y., ABD. RAZAK, C. H. MOHAMMUD, M. MOHD.
ZAIN & M. NORMAH
(Full Text-pdf-5.33MB)
The degradation of paddy soils due to both
physical and chemical processes. A study was conducted in
Kelantan, Malaysia where the top and subsoils of two soil
series (Tok Yong and Kg. Cempaka) planted with paddy and fruit
trees were statistically compared. In this study, a field
experiment was established to measure nutrient and sediment
inputs/outputs in the paddy plots. The Tok Yong series under
paddy and orchards differs significantly in its clay, pH and P
values. In both the soil series, paddy cultivation has
resulted in the depletion of clay and lowering of pH in the
topsoils. The net sediment loss under paddy was about 3 to 4
t/ha/season. Sediment removal by surface water was the highest
during the second rotovation and lowering markedly 90 minutes
thereafter. There was an increase of K and Cu, but N and Zn
decreased. Soil degradation was not easily visible in this
study as its effects were compounded by the various yield
improvement measures undertaken. Using farmer’s practices and
subsidized fertilizer, the rice yield was about 3.5 t/ha, and
this was increased to 6.5 t/ha when MARDI’s technology was
applied. Using FERTO technology, which incorporates organic
manure, the yield was further increased to 8.1 t/ha.
Adsorption of Fecal Coliforms,
Escherichia coli, in Soils of Sarawak
LING, T. Y.,
S. H. GOH & K.APUN
(Full Text-pdf-2.95MB)
In this study, fecal bacterial adsorption in
three different soils (clay loam, silt loam, sandy loam) was
investigated. A wild strain of Escherichia coli (E. coli)
isolated from animal wastewater was used in the study. For
adsorption kinetics study, adhesion of bacterial cells to soil
particles was found to be immediate. Percent adsorption was
found to be dependent on the initial concentration of E. coli.
Results indicate that at low E. coli concentrations (below 103
cfu/ml), the percent adsorption was very much less in sandy
loam than in silt loam and clay loam. However, as the
bacterial concentration increased, all the soils tested
displayed higher bacteria adsorption with maximum values of
99.9% for clay loam, 99.9% for silt loam and 99.7% for sandy
loam. Soil with higher clay content (35.2% and lower pH (pH
4.5)) had significantly higher capacity for adsorbing E. coli.
Furthermore, E. coli concentration of 106 cfu/ml in suspension
was found to decrease by 2 orders of magnitude in all the
three soils. Therefore, land treatment of wastewater from
animal farm lagoons should be considered to reduce microbial
contamination of
rivers.
