This study analysed the variability of the agro-climatic parameters that impact maize production across different seasons in South Africa. To achieve this, four agro-climatic variables (precipitation, potential evapotranspiration, minimum and maximum temperatures) were considered for the period spanning 1986 -2015, covering the North West, Free State, Mpumalanga and KwaZulu-Natal (KZN) provinces. Results illustrate that there is a negative trend in precipitation for North West and Free State provinces and positive trend in maximum temperature for all the provinces over the study period. Further more, the result showed that among other agro-climatic parameters, minimum temperature had the most influence on maize production in North West, potential evapotranspiration (combination of the agro-climatic parameters), minimum and maximum temperature influenced maize production in KwaZulu-Natal while maximum temperature influenced maize production in Mpumalanga and Free State. In general, the agro-climatic parameters were found to contribute 7.79 %, 21.85 %, 32.52 % and 44.39 % to variation in maize production during the study period in North West, Free State, Mpumalanga and KwaZulu-Natal respectively. The variation in maize production amongst the provinces under investigation could most likely attributed to the variation in the size of the cultivated land among other factors including soil type and land tenure system. There were also difference in yield per hectare between the provinces; KwaZulu-Natal and Mpumalanga being located in the humid subtropical areas of South Africa had the highest yield per hectare 5.61 tons and 4.99 tons respectively while Free State and North West which are in the semi-arid region had the lowest yield per hectare 3.86 tons and 3.03 tons respectively.Understanding the nature and interaction of the dominant agro-climatic parameters discussed in the present study as well as their impact on maize production will help farmers and agricultural policy makers to understand how climate change exerts its influence on maize production within the study area so as to better adapt to the major climate element that either increases or decreases maize production in their respective provinces.

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In this study, two commonly used drought indices; the Standardized Precipitation Index SPI and Standardized Precipitation Evapotranspiration Index SPEI , were analyzed in order to understand the impacts of drought on maize yield over four main maize production provinces of South Africa. The drought was characterized using three Drought Monitoring Indicators DMI i.e., the Drought Duration DD , Drought Severity DS , and Consecutive Drought Months CDM . The results indicate that maize yield is significantly affected by drought across the entire study area, although the impacts are localized. A comparison between the SPI and SPEI with maize yield suggests that the SPEI is more correlated and sensitive to maize yield than the SPI. The maize yield is particularly most sensitive to the 3-month SPEI. The 3-month accumulation period coincides with maize growing season r = 0.59; p < 0.05 . The analyzed results illustrate that drought affects maize yield by up to 35 across the study area. Additionally, results depict inherent spatial patterns of DMIs demonstrating that there are differentiated drought impacts across the maize production areas. The results suggest that management strategies that allow for optimal water use within the first 1-and 3-month periods would be most effective for sustainable maize production within the study area. This research study contributes towards a deeper understanding of the characteristics of drought and their impacts on maize crop production. Such knowledge is important in e.g., the formulation of drought monitoring and prediction strategies including drought early warning systems.

Corrosion inhibition of water extract of Spondias mombin on low carbon steel in 0.5 M sulphuric acid was investigated in this paper. Fresh leaves, fruits and bark of this plant, washed properly, ground separately using small amount of distilled water to extract the juice at a ratio of 500 ml (distilled water) to 1 kilogram of plant were used for this experiment. Corrosion inhibitors of 0.4 g/ml, 1 g/ml and 2 g/ml were made from the filterate. Low carbon steel coupons suspended with twine inside 250 ml container of 0.5 M sulphuric acid in the presence of different concentrations of the extracts at room temperature for 35 days. The coupons were retrieved at 7 days interval, and the initial and final weights were recorded.  Inhibition efficiency for the leaves extract increased with concentration and got to its peak on the 7th day, that of the fruits extract initially increased with concentration until 1 g/ml after which there was a decline, its highest value was also recorded on the 7th day. The best inhibition efficiencies (in the range of 76.32% to 83.21%) for Spondias mombin water extract were observed in 0.4 g/ml bark extract throughout the days of the experiment, the highest being recorded on the14th day. It can be concluded that Spondias mombin water extract is a good corrosion inhibitor of low carbon steel in 0.5 M sulphuric acid at room temperature, with the best being the bark extract which inhibited for up to 35 days.

Palm kernel, which is one of the by- products of palm tree is of great importance to the human race and highly sought for, because it contains oil which could be consumed directly or used as raw materials for other products. The plant is mostly found in the rain forest of Nigeria where the production ofª¤? palm kernel is not the major challenge, but the production ofª¤? clean and unbrokenª¤? kernel (high grade) to be sold to the palm kernel merchants who buy and supply to companies. The development of mobile palm kernel nut cracking machine was made to reduce drudgery, to enhance processing capacity and to determine processing loss. Palm kernel nut cracking occurs when nuts are loaded to rupture without crushing the embedded kernel. The aim of this research work was to assess the performance of the developed mobile palm kernel nut cracking machine. Total sample of four thousand (4,000) palm kernel nuts were divided into five groups of eight hundred palm kernel nuts and each group was further divided into four sub-groups of two hundred (200) palm kernel nuts.ª¤? Each group of five was fed into the hopper and cracked at different shaft speeds in revolutions per minute (rpm). The shaft speeds were determined with a tachometer and it was varied on the engine by adjusting the throttle lever. In a group of five, it was replicated for four different times at the same speed. The cracking efficiency and throughput capacity were calculated. The research work showed that the cracking efficiencies at speeds of 1200, 1800, 2200 and 2400 rpm were 98ª¤¡Þ0.3, 98.5ª¤¡Þ0.08, 98.5ª¤¡Þ0.01 and 99ª¤¡Þ0.04% respectively. The throughput of the machine increased from 10.91 to 38.00 g/s as the speed of the machine increased from 800 to 2400 rpm. Also the performance efficiencies of the developed machine were 93, 94, 95, 94.5 and 94% while the overall efficiencies were 90.86, 92.12, 93.58, 93.08 and 93.06% for the set speeds. It was concluded that the overall performance of this developed palm nut kernel cracking machine were effective because it fell within the range of betweenª¤? 90 to 98% overall efficiency.ª¤?