Advances in Research

Aims: Suitability of land for growing crops, which considers the spatial distribution of soil characteristics, is an important factor to consider in order to maximize yields and ensure judicious land-use planning. This study was conducted to assess the suitability of Nzema series according to Land Suitability Classification for rainfed rice cultivation. The study was undertaken at Nkrankwanta lowland in the Dormaa West District, Ghana.

Methods: Two pedons were dug at a depth of 0-140 cm for both sampling locations. A total of 50 soil samples were collected at a depth of 0-20, 20-40, 40-60, 60-100, and 100-140 cm depth. Suitability assessment was done using the FAO Land Quality Index with input parameters including pH, texture, stoniness, nitrogen, depth, organic carbon, slope, and drainage.

Results: Chemical analysis revealed that nitrogen, phosphorus and organic matter were generally low. The results showed that pH for both pedons ranged from very strongly acidic to slightly alkaline (4–7.8) which could be as a result of leaching of basic cations due to the regular flooding of the lowland. The two pedons are deep >140 m and the drainage is imperfect to poorly drained. Soil Quality Index was 0.8 whilst Nutrient Availability Index was 0.05, indicating highly suitable and marginally suitable land for rice production respectively.

Conclusion: Based on this analysis, Nkrankwanta lowland is marginally suitable (0.04) for rice production. The soil is potentially highly suitable if continuous monitoring of the pH status is carried out. Nutrient management is recommended to improve the low fertility status of the soil.

Banana Bunchy Top Disease (BBTD) is one of the most severe viral diseases affecting major banana growing belts in India. Banana Bunchy Top Virus (BBTV) is transmitted by a black banana aphid (Pentalonia nigronervosa L Coquerel) in a persistent manner. BBTV virions are limited to the phloem tissue of banana resulting in low titre in banana. A reliable method to quantify the BBTV in the banana will be useful for monitoring the insect vector mediated BBTV transmission in banana, an essential requirement for characterizing the transgenic banana transformed for BBTV resistance. A protocol for real time PCR based absolute quantification of BBTV is reported in the present study. The partial BBTV coat protein gene (459 bp) was isolated, cloned into a plasmid vector and used to construct a standard curve using an SYBR green-based assay with known copies of BBTV coat protein gene. Using the standard curve, BBTV viral load was estimated in BBTV infected symptomatic and asymptomatic leaf samples of banana cultivar Grand Naine through SYBR green-based quantitative Polymerase Chain Reaction (qPCR). The study demonstrated that a higher viral tire was associated with BBTV disease symptoms appearance, whereas the low titre resulted in asymptomatic plants.

This paper presents the results of finite element (FE) analysis of axially loaded square hollow structural steel (HSS) columns, strengthened with polymer-mortar materials. Three-dimensional nonlinear FE model of HSS slender columns were developed using thin-shell element, considering geometric and material nonlinearity. The polymer-mortar strengthening layer was incorporated using additional layers of the shell element. The FE model has been performed and then verified against experimental results obtained by the authors [1]. Good agreement was observed between FE analysis and experimental results. The model was then used in an extended parametric study to examine selected AISC square HSS columns with different cross-sectional geometries, slenderness ratios, thicknesses of mortar strengthening layer, overall geometric imperfections, and level of residual stresses. The effectiveness of polymer-mortar in increasing the column’s axial strength is observed. The study also demonstrated that polymer-mortar strengthening materials is more effective for higher slenderness ratios. An equivalent steel thickness is also accounted for the mortar strengthened HSS columns to discuss the effectiveness of polymer-mortar strengthening system. The polymer-mortar strengthening system is more effective for HSS columns with higher levels of out-of-straightness. Level of residual stress has a slight effect on the gain in the column’s axial strength strengthened with polymer-mortar.

Threshing of sesame seeds from the harvested capsules is one of the important operations and it consumes more labor, time and cost. Hence the development of a power operated portable sesame thresher is timely essential for the small farmers. The physical properties of sesame seeds namely size of the seed, Number of seeds per capsule, 1000 grain weight and length and thickness of capsules were studied for developing a power operated portable sesame thresher. The most popular variety used in Tamil Nadu is TMV 7. The average length and thickness of capsules were measured as 35 and 12 mm respectively. The average number of seeds in single capsule was determined as 60. The average 1000 grain weight was determined as 3.1 g. and the average size of the seed is 3×1.8× 0.9 mm. Based on these results the portable sesame thresher was fabricated based on double roller (two rollers are rotating with opposite direction) mechanism with an overall size of 1392 ×700 ×1170 mm and its performance was assessed in terms of threshing efficiency, output capacity, saving in cost and time and compared with conventional methods of manual threshing. The developed portable power sesame thresher was field tested and its threshing efficiency and seed output capacity were 96.7% and 18.2 kg h^-1, respectively. The saving in cost and time were 92 and 72% respectively as compared to conventional method of manual threshing.

The study was conducted to evaluate the influence of different levels of crude oil pollution remediated with spent mushroom substrate (SMS) on the growth of maize after one month of pollution. Composite soil samples randomly collected were polluted with Bonny light crude oil (v/w) at a concentration of 0%, 2%, 4% and 6% in a perforated plastic pots with 6 kg of top soil (0-20) cm.  Ten percent of decomposed SMS was applied on each of the pots. A month after remediation, four seeds of Oba Super 11 maize variety were sown into each pot and later thinned to two after germination. The design was Complete Randomized Design consisting of six treatments and four replicates. After eight weeks of the study, results revealed a reduction in plant germination rate (60%) in polluted (SCM) against (87%) in non-polluted (SM) soil. Plant germination was highest (93.8%) on natural soil (SSM) amended with SMS. Amendment of the polluted soil with SMS improved the germination of the plant from 60% to 75%. There was a significant (P<0.01) decrease in plant height on polluted against natural soils. Amendment of the polluted soil with SMS slightly increased the height of the plant though not significant within the first six weeks of the study, however, a significant (P<0.01) increase was observed on the seventh and eighth weeks of the study. Pollution of the soil with crude oil revealed significant (P<0.01) reduction on some soil physico-chemical properties (available phosphorus, exchangeable cations (Ca, Mg and K), while a significant (P<0.01) increase was observed on total hydrocarbon content, total nitrogen, total organic carbon and total organic matter on the polluted over natural soil. Amendment of the polluted soil with SMS improved the nutrient status of the soil as there was significant (P<0.01) increase in the concentration of Ca, Mg, K, P and a reduction in the content of THC, TOC of the soil. Remediation of crude oil polluted soil, with spent mushroom substrate a month after pollution, improved soil fertility.