July 2010 issue

Mass modeling of two apple varieties by geometrical attributes

Sat, 15 May 2010 10:06:14 GMT

A. Gorji Chakespari, A. Rajabipour and H. Mobli

Abstract

In this study mass of two Iranian apple varieties (Golab Kohanz and Shafi Abadi) were predicted using different physical
characteristics in linear models as three different classifications: (1) single or multiple variable regressions of apple dimensional
characteristics. (2), single or multiple variable regressions of apple projected areas and (3), estimating apple mass based on its
volume. All properties considered in the current study were found to be statistically significant at the 1% probability level. The
performance of the models was evaluated by a set of test data using three different measures including the root mean square error
(RMSE), the coefficient of determination (R2) and the mean error (ME) between predicted and measured values. In the first
classification among single variable models the model based on width (M= 3.29W-116.25) had maximum coefficient of determination,
R2=0.91 for Golab Kohanz variety and the model based on thickness (M=3.29T-118.06) had maximum coefficient of determination,
R2=0.91 for Shafi Abadi variety, respectively. Among all of single variable models, the mass model based on actual volume was the
best model for both varieties. For multiple variable regression models the best models were based on three dimension and three
projected areas for all observation.

Growth and yield in maize/cassava intercrop as affected by interactions of weed control methods

Sat, 15 May 2010 10:05:14 GMT

Olorunmaiye, P. M.

Abstract

The response of food crops to integrated weed management involving the used of pre-emergence herbicides, hoe-weeding and live
mulch of herbaceous cover plants in a maize/cassava intercrop was investigated at the Teaching and Research Farm of the University
of Ilorin between 2002 and 2004. The experiment consisted of eight main treatments and six sub treatments. The main treatments
were made of the application of two of pre-emergence herbicides (Primextra and Galex each at 2.5kg a.i./ha alone, or with one or
two supplementary hoe-weeding at 6 weeks after planting (WAP) or 6 and 12WAP), a hoe-weeded check (hoeing at 3, 6 and 12WAP)
and a weedy control. The sub treatments consisted of five legume cover crops (Pueraria phaseoloides, Stylosanthes guianeesis,
Mucuna pruriens var. utilis, Mucuna preta and Mucuna jaspeada) and a legume cover plot as control. Data were collected for the
vegetative and reproductive parameters for both crops. Results showed that the various treatment combinations supported good
vegetative growth in maize except at 9WAP where plots treated with Galex alone under the mucuna species produced significantly
shorter plants as in weedy plots. However, cassava plant height was significantly higher in plots with 3 hoe-weeding under S.
guianensis cover and Galex + 2HW without legume (NL) cover at 12 and 16WAP respectively, compared to other treatment
combimnations. Maize grain yield was significantly higher in the treatment combination involving Primextra with two hoe-weeding
under M. pruriens var. utilis cover for both years while average cassava fresh tuber yield was significantly higher in the combination
involving Primextra with two hoe-weeding under Pueraria Phaseoloides. Maize grain yield and cassava fresh tuber yield in treatment
combinations of the two pre-emergence herbicides alone under the various cover crops produced yields that were not significantly
different from what was obtained in weedy plots.

Reproductive performance of two Cowpea (Vigna unguiculata (L)Walp) varieties Ife brown and TVX3236 as influenced by

Sat, 15 May 2010 10:04:37 GMT

Olorunmaiye KS.

Abstract

Weed control management was carried out in plots of two cowpea (Vigna unguiculata (L) Walp) varieties Ife brown and TVX3236 at
the University of Ilorin main Campus during 2004 and 2005 cropping seasons. Imidazolinone (Imazaquin, and Imazethapyr) and
Dinitroaniline (pendimethalin) herbicides were used as weed control agents. Results of this study revealed that these herbicides
were adequate both as pre and early post emergence applications for weed control in cowpea without serious set back on the
reproductive parameters such as number of pods per plant, pod weight per plant, seed number per plant, pod length, seed number
per pod and pod filling potential. Seed number per pod was higher in herbicide treatments than the weedy control in both cowpea
varieties. However, reduction in seed number per pod was noticed in higher concentration of 0.375 kg a.i./ha in the pre-emergence
application of pendimethalin, pursuit plus and the early post emergence application of pursuit plus. There was no reduction in the pod
length of both varieties by any of the herbicide treatments.

Impact of spatially variable soil salinity on crop physiological properties, soil water content and yield of wheat in a semi arid

Sat, 15 May 2010 10:04:02 GMT

Prakash N. Dixit, Deli Chen

Abstract

In the Birchip region of the Victorian southern Mallee, Australia, subsoil salinity is an important factor determining crop growth and
yield. Crop simulation models have performed poorly in this region, presumably due to their inability to account for subsoil
constraints, mainly salinity. The objective of this work was to study the impact of subsoil salinity on crop physiological properties,
growth, water use and yield of a wheat crop. From a calibrated electromagnetic survey (EM 38) over an area 7 m wide by 100 m
long, three sites of low, medium and high salinity levels were identified. For each site, soil electrical conductivity was measured and
the values averaged for the depth 0-70 cm were 0.25, 1.14 and 1.63 dS/m at the sites with low, medium and high salinity,
respectively. Further, at different stages of crop growth, radiation interception by the canopy as well as soil water content were
measured while plant samples were collected to estimate crop physiological properties. Grain yield at each salinity site was also
measured. All the physiological properties and yield were negatively affected by increasing salinity levels due to less water use and
radiation interception. Compared to the low salinity level, medium and high salinity levels reduced the above-ground dry weight of the
crop at harvest by 40% and 41%, accumulated intercepted radiation by 23% and 37%, radiation use efficiency by 25% and 52%,
water use by 18% and 35% and grain yield by 41% and 48%, respectively.

Compressive strength of fibre reinforced earth plasters for straw bale buildings

Sat, 15 May 2010 10:03:17 GMT

Taha Ashour, Adel Bahnasawey, Wei Wu

Abstract

An experimental study into the compressive strength of fibre reinforced earth plasters is presented. The plaster material is composed
of cohesive soil and sand. Three types of natural fibers are used as reinforcement, namely, wheat straw, barley straw and wood
shavings. Ten different types of plasters with different compositions of earth materials and reinforcement are investigated. The fiber
has positive effect on both the strength and ductility of plasters. While the fibre has remarkable effect on the strength and ductility of
plasters, its effect on the elastic modulus of plasters is relatively small.

The effect of diesel fuel-Jatropha curcas oil methyl ester blend on the performance of a variable speed compression ignition engine

Sat, 15 May 2010 09:59:31 GMT

Ejilah I.R., Asere A.A., Adisa, A. B. and Ejila, A.

Abstract

The increase in crude oil prices, the problems associated with long term availability of conventional hydrocarbon fuels for automotive
engines, and the continuous emission of combustion pollutants into the environment are cause for concern. These challenges have
necessitated the need to investigate the performance of Jatropha curcas oil methyl ester as diesel fuel extender in compression
ignition engines. A test rig of 2.43 kW, 165 F single cylinder -four stroke variable speed direct injection engine, and incorporated with
a 1.25kVA Honda E 1500 A.C dynamometer manufactured by Ningbo Tri-circle Power Machinery Company, China and Honda
Company, Japan, was used to conduct the engine performance tests on samples of fossil diesel fuel (DF), and diesel fuel containing
5%, 10%, 15%, and 20% by volume of Jatropha curcas oil methyl ester (i.e. B5, B10, B15, and B20 DF-JME blends) respectively. At
maximum engine speed of 2600rpm, the brake power and brake mean effective pressure generated by DF-JME blends are somewhat
comparable to fossil DF, with B10 and B20 samples exhibiting least engine power by the order of 1.80% and 2.72%. In terms of fuel
consumption, B5, B10, B15 and B20 DF-JME blends are 1.63%, 3.06%, 0.030% and 0.514% higher than fossil DF. However, the lower
break thermal efficiency could be attributed to the slow progress of combustion, lower heating value and combustion temperature of
the DF-JME fuel mixture. Hence, it could be concluded from this study that transesterified Jatropha curcas oil is suitable for use as
diesel fuel extender in compression ignition engines. To this effect, a deliberate investment in biodiesel production from Jatropha
curcas oil will conserve crude oil reserve and improve Nigeria’s energy security.

The Effectives of Indigenous Soil Conservation Techniques on Sustainable Crop Production

Sat, 15 May 2010 09:58:30 GMT

Tekwa I J, Belel M D and Alhassan AB

Abstract

Soil and water conservation techniques remain an indispensable tool in sustaining crop production especially on farm lands under
severe soil degradation. Six (6) village farm locations (Humbutode, Gella, Digil, Yewa, Hurida and Duda) within Mubi area that apply
indigenous soil and water conservation techniques (Hillside-terraces, stone-bunds, stone-lines, sand-bag lines, trash-lines,
vegetative-barriers, earth-contour bunds, rice-bran mulch and organic-manuring) were surveyed and assessed for effectiveness
between April and November, 2006. Parameters related to soil degradation such as vegetation, topography, land slope, soil textural
class and erosion types were equally noted and/or measured. Data collected were statistically analysed and compared using Likert
scaling test. The result indicated that Hillside-Terraces (Gella and Duda), earth-contour bunds (Humbutode), vegetative-barriers
(Digil, Yewa and Hurida), rice-bran mulch (Digil and Yewa) and organic-manuring (Digil) effectively conserved soils against erosion
losses that characterize the Mubi undulating topography. The challenge to optimally sustain a timeless food crop returns through
locally effective soil and water conservation methods feasible in Mubi area were equally addressed.