Commencement Of Rains Research Articles

Effect of planting date on the growth, fibre and seed yield of Kenaf (<i>Hibiscus cannabinus</i> L) in Ibadan, South Western Nigeria

Planting of kenaf usually commences from March - April as these months mark the onset of the rainy season in Nigeria. On the contrary, it is now difficult for anyone to predict when rain start due to climatic variation. Hence, field experiments was conducted between 2015 and 2016 to determine the appropriate time of sowing kenaf that will optimize its yield potential in South Western Nigeria. As a result of delay in the commencement of rain, planting did not start until May. Hence, kenaf seeds were sown in May, June, July and August at 30 days interval in each year. The experiment was a 4 × 2 factorial laid out in a randomized complete block design and replicated three times. The result indicated that the highest fibre yield (1.00 t/ha) was from the kenaf sown in June irrespective of the year, but not significantly different from the one sown in July (0.98 t/ha). On the other hand, kenaf sown in July had the highest seed yield (2.28 t/ha) with the lowest seed yield (1.04 t/ha) obtained in May followed by August (1.19 t/ha). The experiment conclusively affirm June for sowing of kenaf for fibre cultivation and July for seed production.
 Keywords: Planting date, kenaf, fibre and seed yield

English

The present study was made to assess the water quality of Ulsoor Lake, Bangalore, India before and after the monsoon season. To carry out the study, samples were collected from the lake before and after the commencement of Rains. Various parameters such as pH, Temperature, Electrical Conductivity(EC), Total dissolved solids(TDS), Total hardness(TH), Total alkalinity(TA), concentration of Ca2+ and Mg2+ ions etc were determined. These parameters were then compared with the WHO and ISI standards to draw the final conclusion on the quality of the lake water before and after the rainy season.

Physico-chemical and bacteriological quality of rainwater in Egbema, Imo state, Nigeria

Egbema is one of the oil-producing communities in Nigeria and has no access to pipe-borne water, and thus resorts to rainwater as a source of water supply mainly during the rainy season. Physico-chemical and bacteriological quality of rainwater in Egbema was determined with samples harvested directly, from zinc roof, thatched roof and asbestos roof, at different periods of the rainy season namely, Early, peak and late rains. The values of the physico-chemical parameters were on the higher side at the early rains, but moderate (within acceptable range) at the peak and late rains. The values of copper, turbidity, total iron, total hardness and total solids were lowest in rain water harvested directly and highest in that harvested from asbestos roof throughout the rainy period. Generally, the values of the parameters measured in samples from different sources tended to increase in this order: asbestos > thatched roof > zinc roof > direct. The heterotrophic bacterial load was highest at the commencement of rains ranging from 0.45 x 103 cfu/ml to 7.40 x 103 cfu/ml. Also the total coliforms count and fecal coliforms (Escherichia coli) count ranged highest at the early rains between 10 – 22 cfu/100ml and 2 –4 cfu/100ml respectively. The values of heterotrophic bacterial load, total coliforms and fecal coliforms, were within the acceptable range in rainwater samples collected at the peak and late rains. However the bacterial count recorded highest in the samples harvested in the thatched roof and lowest in samples harvested directly direct at the early, peak and late rainy season. This study reveals that rainwater collected at the peak and end of rains from zinc roof and directly if well handled, can be used for drinking and any other domestic purposes. International Journal of Natural and Applied Sciences Vol. 2 (4) 2006: pp. 372-376

Variations in hydrochemistry, trace metal concentration and transport during a rain storm event in a small catchment

General hydrochemistry and trace metal concentrations were monitored during a runoff event in a small catchment (0.9 km 2) with an old abandoned copper mine and covered sulphidic waste. Five hours of rising hydrograph was sampled manually every 10 minutes while an automatic sampler was used during the recession phase. The hydrograph started to rise about two hours after the commencement of rain, but the hydrochemistry showed only small changes for yet another hour and a half. At this time the concentration of total organic C (TOC), Cu and Zn decreased rapidly, while most other elements exhibited a peak in concentration. Different origins and varying hydrological response could explain these observations. Chemical redistribution might, however, be important for some elements, notably Al and Fe. After this peak the concentrations of most elements decreased, probably because of dilution with precipitation water whereafter a secondary concentration maximum was observed. This behaviour was most evident for K but also for Na, Mg and Ca. A noteworthy exception is pH that increased during the event and remained at high levels, while concentrations of Mn and Cd were lowered possibly due to depletion of the mobile pool. Increased pH during the event is probably caused by liming of soils surrounding the creek, in combination with soil buffering processes. The increase of alkaline and alkaline earths (notably K) concentrations could be explained by transport of accumulated elements as the groundwater level rose.

Reliability of ferrocement slabs under cyclic thermal-shock loading

The reliability of ferrocement slabs subjected to cyclic thermal-shock loading induced by raindrops during service is investigated. The data are obtained experimentally by subjecting specimens to heating and wetting cycles and monitoring the residual first-crack strength at different periods. The imposed thermal-shock loads simulate actual service conditions and are estimated by monitoring the temperature of typical roofing slabs just before the commencement of rain over a period of time. The mean deterioration in strength obtained after correcting for curing effects due to ageing and temperature, as well as the uncertainty present, are used to assess the reliability of slabs having residual first-crack strengths above some prescribed values at different periods. The results indicate that ferrocement slabs posses good flexural resistance with respect to the cyclic loadings studied and are suitable for use as roofing elements.

Population dynamics of a tropical lepidopteranCatopsilia crocale (Pieridae)

Extensive field observations were undertaken to study the population dynamics of the larvae ofCatopsilia crocale in the Madurai Kamaraj University campus during the years 1980–81 and 1981–82. Though oligophagous,C. crocale adopted ‘monophagic strategy’ for oviposition and larval feeding. Seasonal changes in the nitrogen content of the foodCassia alata leaf influenced the pupal/adult weight and oviposition. Commencement of rain triggered the reproductive activity and continued precipitation facilitated maximum egg deposition. Of total egg production in a year, about 80% was oviposited during northeast monsoon (September–December) and the rest during the south-west monsoon (May–August). Egg, I instar, V instar and pupa suffered more mortality than the other life stages. Of the total number of eggs laid, about 1·01% emerged as adult and 98·99% died during the process of larval and pupal development.

Probability analysis of rainfall and evolving Cropping system for Coimbatore

The daily precipitation data of Coimbatore centre for a period of 70 years were computed for weekly totals by fitting incomplete gamma distribution. model in an IBM computer. The assured weekly rainfall amounts with different probability levels and the probability of receiving a given amount of rainfall were worked out and presented. The data indicate the likely commencement of rains, period of drought, length of growing season and end of growing season. Based on the assured rainfall at 50 percent probability level suitable cropping system was suggested for Coimbatore.