Late Wet Season Research Articles

SEAS5 skilfully predicts late wet‐season precipitation in Central American Dry Corridor excelling in Costa Rica and Nicaragua

AbstractBetter drought preparedness is critically needed in the Central American Dry Corridor (CADC). Seasonal forecasts can be used to build this preparedness but need localized evaluations to ensure they are relevant and useful. This study provides a CADC‐focused assessment of the SEAS5 seasonal forecasting system produced by the European Centre for Medium‐Range Weather Forecasts (ECMWF). We evaluate SEAS5 predictions of the mean, variability, and extremes of precipitation across the CADC at 1–7‐month lead times. We assess differences in regional forecast quality across seasons and lead times by evaluating spatial and temporal associations with El Niño–Southern Oscillation (ENSO) phase, topography, and continentality. Results show that SEAS5 precipitation forecasts often have better skill primarily during the mid to late wet season (July–October). In these months, low/normal precipitation forecasts outperform the climatological mean (1982–2016) up to 5‐ or 6‐month lead times in some subregions. Forecast skill is often worse, however, for predicting precipitation during the early wet season, primarily in June. Forecast skill varies spatially across the region, with higher skill concentrated in the southeast (Costa Rica and Nicaragua). Forecast skill is significantly related to continentality and topography, and together these factors account for at least a quarter of the spatial variance in annual skill at all lead times. Forecast accuracy varies depending on ENSO phase: predictions are often worse in El Niño (warm ENSO) periods during the early wet season when ENSO also has a weaker association with cumulative precipitation relative to the later wet season. SEAS5 could be a particularly useful tool during the second half of the wet season in the southeast CADC, skilfully alerting of upcoming precipitation variability with over 3‐month lead times.

The other side of tropical forest drought: do shallow water table regions of Amazonia act as large-scale hydrological refugia from drought?

Tropical forest function is of global significance to climate change responses, and critically determined by water availability patterns. Groundwater is tightly related to soil water through the water table depth (WT), but historically neglected in ecological studies. Shallow WT forests (WT < 5 m) are underrepresented in forest research networks and absent in eddy flux measurements, although they represent c. 50% of the Amazon and are expected to respond differently to global-change-related droughts. We review WT patterns and consequences for plants, emerging results, and advance a conceptual model integrating environment and trait distributions to predict climate change effects. Shallow WT forests have a distinct species composition, with more resource-acquisitive and hydrologically vulnerable trees, shorter canopies and lower biomass than deep WT forests. During 'normal' climatic years, shallow WT forests have higher mortality and lower productivity than deep WT forests, but during moderate droughts mortality is buffered and productivity increases. However, during severe drought, shallow WT forests may be more sensitive due to shallow roots and drought-intolerant traits. Our evidence supports the hypothesis of neglected shallow WT forests being resilient to moderate drought, challenging the prevailing view of widespread negative effects of climate change on Amazonian forests that ignores WT gradients, but predicts they could collapse under very strong droughts.

High-fidelity representation of climate variations by Amburana cearensis tree-ring chronologies across a tropical forest transition in South America

Numerous ring-width chronologies from different species have recently been developed in diverse tropical forests across South America. However, the temporal and spatial climate signals in these tropical chronologies is less well known. In this work, annual growth rings of Amburana cearensis, a widely distributed tropical tree species, were employed to estimate temporal and spatial patterns of climate variability in the transition from the dry Chiquitano (16–17°S) to the humid Guarayos-southern Amazon (14–15°S) forests. Four well-replicated chronologies (16–21 trees, 22–28 radii) of A. cearensis were compared with temperature and precipitation records available in the region. The interannual variations in all four A. cearensis tree-ring chronologies are positively correlated with precipitation and negatively with temperature during the late dry-early wet season, the classic moisture response seen widely in trees from dry tropical and temperate forests worldwide. However, the chronologies from the dry Chiquitano forests of southern Bolivia reflect the regional reduction in precipitation during recent decades, while the chronologies from the tropical lowland moist forests in the north capture the recent increase in precipitation in the southern Amazon basin. These results indicate that A. cearensis tree growth is not only sensitive to the moisture balance of the growing season, it can also record subtle differences in regional precipitation trends across the dry to humid forest transition. Comparisons with previously developed Centrolobium microchaete chronologies in the region reveal a substantial common signal between chronologies in similar environments, suggesting that regional differences in climate are a major drivers of tree growth along the precipitation gradient. The difficulty of finding A. cearensis trees over 150-years old is the main limitation involved in the paleoclimate application of this species. The expansion of monocultures and intensive cattle ranching in the South American tropics are contributing to the loss of these old growth A. cearensis trees and the valuable records of climate variability and climate change that they contain.

Reproductive cycle in the male African fruit bat (Epomops franqueti)

Epomops franqueti is common in Sub-Saharan Africa. Unlike micro chiropteran, information on the reproductive activity of this bat is scanty. The morpho-physiology of the testis and epididymis of E. franqueti was investigated to determine the seasonal reproductive activity. Sixty adult male E. franqueti were captured at the University of Ibadan, Nigeria. Histomorphometry of the testis and epididymis was investigated. Serum hormonal assays were carried out using ELISA. Concentrations of testosterone, FSH, and LH were least (0.25, 5.80, and 7.01 IU/L, respectively) and highest (3.80, 12.03 and 14.04 IU/L, respectively) during late dry and late wet seasons, respectively, being significantly different. The early and late wet seasons had the highest gonadosomatic (0.20%) and epididymal mass (0.08%) indices, respectively. The least values were recorded during the early dry season for both gonadosomatic (0.15%) and epididymal mass (0.06%) indices. Epomops franqueti may be a seasonal breeder.

Steady agronomic and genetic interventions are essential for sustaining productivity in intensive rice cropping.

Intensive systems with two or three rice (Oryza sativa L.) crops per year account for about 50% of the harvested area for irrigated rice in Asia. Any reduction in productivity or sustainability of these systems has serious implications for global food security. Rice yield trends in the world's longest-running long-term continuous cropping experiment (LTCCE) were evaluated to investigate consequences of intensive cropping and to draw lessons for sustaining production in Asia. Annual production was sustained at a steady level over the 50-y period in the LTCCE through continuous adjustment of management practices and regular cultivar replacement. Within each of the three annual cropping seasons (dry, early wet, and late wet), yield decline was observed during the first phase, from 1968 to 1990. Agronomic improvements in 1991 to 1995 helped to reverse this yield decline, but yield increases did not continue thereafter from 1996 to 2017. Regular genetic and agronomic improvements were sufficient to maintain yields at steady levels in dry and early wet seasons despite a reduction in the yield potential due to changing climate. Yield declines resumed in the late wet season. Slower growth in genetic gain after the first 20 y was associated with slower breeding cycle advancement as indicated by pedigree depth. Our findings demonstrate that through adjustment of management practices and regular cultivar replacement, it is possible to sustain a high level of annual production in irrigated systems under a changing climate. However, the system was unable to achieve further increases in yield required to keep pace with the growing global rice demand.

Environmental Implication of Thermal Radiation on the Physiochemical Properties of Soil around Gas Flare Sites in the Niger Delta Region of Nigeria

The effect of thermal radiation on the Physiochemical properties of soil around gas flare site in the Niger Delta region was assessed in Emuoha Local Government Area of River State, Nigeria, for a period of twelve months. Radiation profile was determined at different times (hours) – 6, 10, 14, 18 and 22, in the four seasons (early dry, early wet, late dry and late wet) of the year. Soil samples were taken at different depths (cm) (0-15 and 15-30) for physicochemical attributes at different distances (m) (0-150, 150-300, 300-450, 450-600 and 1000 -2000) from the flare site and thermal radiation was also determined at the respective distances. Results of effect of time and seasonal variations on radiation profile showed that environmental temperature (oC) ranged from 29.2 ± 0.3 at 22 hours of early wet season to 33.0 ± 0.4 at 14 hours of late dry season; radiation temperature ranged from 35.4 ± 1.2 at 22 hours of late wet season to 42.0 ± 1.4 at 14 hours of late dry season, while thermal radiation (w/m2) ranged from 490.83 ± 7.7 at 22 hours of late wet season to 535.69 ± 9.69 at 14 hours of late dry season. Results of effect of flare distance on physicochemical properties of soil showed that as the distance (m) from flare site increases from 0 – 150 to 1000 – 2000, the radiation intensity (w/m2) decreases from 603.84 ± 5.7 – 428.83 ± 0.75, and values of pH, OC, N, P, and exchangeable cations - K+, Na+, Ca2+, Mg2+ increases in the range {pH (4.94 ± 0.02 – 5.50 ± 0.00), OC (1.09 ± 0.01 – 2.05 ± 0.00), N (0.07 ±0.01 – 0.09 ± 0.00), P (10.90 ± 0.03 – 12.10 ± 5.19), K+ (0.28 ± 0.01 – 1.86 ± 0.01), Na+ (0.48 ± 0.00 – 1.04 ± 0.00), Ca2+ (1.65 ± 0.01 – 2.85 ± 0.00), Mg2+ (0.73 ± 0.01 – 1.24 ± 0.01)}, These values seemed not to be affected by the thermal radiation and flare distance , oil and grease and THC decreases in the range 203.30 ± 0.88 – 61.33 ± 0.33 and 352.90 ± 2.08 – 10.04 ± 0.04 respectively. Similar trend was observed with soil samples taken at 15-30cm depth. Statistical analysis showed there is significant difference (p&lt;0.001) in soil attributes as distance from flare distance increases. Further studies should be carried out to investigate the relationship between soil around flare site and crop performance on different agro-ecological zone of Rivers State.

Influence of period of weed interference and age of pepper (Capsicum annuum L. cv. Cayenne pepper) seedlings on pepper fruit quality and marketability

The field trials were conducted in the early and late wet seasons of 2012 at the Federal University of Agriculture, Abeokuta, Ogun State, Nigeria. The objective of the study was to evaluate influence of period of weed interference on fruit quality and marketability of pepper fruit under different seedling ages. Split-plot arrangement in a randomized complete block design with three replicates was adopted in the trials. The main plot treatments were ages of pepper seedlings at transplant, four and six weeks after sowing (WAS). Sub-plot treatments consisted of 10 periods of weed interference. Data collected on weed cover score, cumulative dry weed weight, dry plant biomass, number of leaves, fruit girth, fruit length, marketable fruit count and yield as well as non-marketable fruit count and yield were subjected to analysis of variance and treatment means were separated using least significant difference at p ≤ 0.05. The results showed that six week old pepper seedling had higher plant biomass, number of leaves and marketable fruit yield than the four week old. Also, pepper growth parameters, pepper fruit quality and marketability increased with weed free period and decreased with weed infestation period. Uncontrolled weed infestation for whole season caused 98.4% and 91.8% reduction in pepper marketability in the early wet and late wet season, respectively.

Seasonality of adverse birth outcomes in women with and without HIV in a representative birth outcomes surveillance study in Botswana

IntroductionSub-Saharan Africa has the largest number of people with HIV, one of the most severe burdens of adverse birth outcomes globally and particular vulnerability to climate change. We examined associations...

Assessing the effect of improved feed trough on feed utilization by small ruminants in Northern Ghana

The feeding systems of small ruminants in Northern Ghana are characterized by waste which necessitates efficient use of the available feed resources, particularly in the dry season. To this end, the use of improved feed trough was demonstrated in three communities in Northern Ghana, namely Duko and Tibali in Northern region; Gia in Upper East region in the late dry, wet, and early dry seasons between March 2019 and February 2020. This study involved 10 farmers randomly selected in each community. The participating farmers were provided with one improved feed trough each which was then compared to the traditional feed trough. Data were collected on the quantity of feed offered, amount wasted, and time spent feeding the animals for six consecutive days in the three study sites across seasons. To document the perception of the farmers on the improved feed trough, a semi-structured questionnaire was administered. Results showed that improved feed trough reduced feed waste significantly in the study sites across seasons. For example, the percentages of waste in feeding the animals using the traditional feed trough were 35%, 22%, and 27% in Duko, Gia, and Tibali, respectively, in the late dry season compared to less than 1% with the improved feed trough during the same season. The farmers' perceptions were similar to the findings of this study which suggest that efficient feed utilization by small ruminants can be enhanced with the use of improved feed trough.

Transmission of 'Candidatus Anaplasma camelii' to mice and rabbits by camel-specific keds, Hippobosca camelina.

Anaplasmosis, caused by infection with bacteria of the genus Anaplasma, is an important veterinary and zoonotic disease. Transmission by ticks has been characterized but little is known about non-tick vectors of livestock anaplasmosis. This study investigated the presence of Anaplasma spp. in camels in northern Kenya and whether the hematophagous camel ked, Hippobosca camelina, acts as a vector. Camels (n = 976) and > 10,000 keds were sampled over a three-year study period and the presence of Anaplasma species was determined by PCR-based assays targeting the Anaplasmataceae 16S rRNA gene. Camels were infected by a single species of Anaplasma, 'Candidatus Anaplasma camelii', with infection rates ranging from 63-78% during the dry (September 2017), wet (June-July 2018), and late wet seasons (July-August 2019). 10-29% of camel keds harbored 'Ca. Anaplasma camelii' acquired from infected camels during blood feeding. We determined that Anaplasma-positive camel keds could transmit 'Ca. Anaplasma camelii' to mice and rabbits via blood-feeding. We show competence in pathogen transmission and subsequent infection in mice and rabbits by microscopic observation in blood smears and by PCR. Transmission of 'Ca. Anaplasma camelii' to mice (8-47%) and rabbits (25%) occurred readily after ked bites. Hence, we demonstrate, for the first time, the potential of H. camelina as a vector of anaplasmosis. This key finding provides the rationale for establishing ked control programmes for improvement of livestock and human health.

Species-specific biomass and carbon flux in Sundarbans mangrove forest, Bangladesh: Response to stand and weather variables

The species-specific potentiality of mangroves in terms of ecosystem services is not well understood. Therefore, this study addressed the carbon sequestration and litterfall production potentiality of six major species in Sundarbans, Bangladesh, by evaluating three consecutive years of inventory data, including the stand variables and weather events impacts on them. The total mean aboveground, belowground biomass, biomass accumulation, and carbon accumulation rate were 243.4 Mg ha−1, 132.2 Mg ha−1, and 14.3 Mg ha−1 yr−1, 7.2 Mg ha−1 yr−1, respectively. Carbon stocks and sequestration rates are significantly influenced by stand variables such as diameter, density, and species composition. Large-sized trees and stands with lower density sequester more carbon than small-sized trees, and higher density stands. Among species, Avicennia officinalis contributed higher carbon to carbon stocks and also significantly different from other species for sequestering carbon, whereas Aglaia cucullata was the lowest. Mean annual litterfall was 10.01 Mg ha−1 yr−1, with the maximum litterfall for Hereteira fomes (19.2 Mg ha−1 yr−1) during the late summer or wet season (e.g., April to August). Litterfall showed a significant positive (p < 0.001) relation to weather variables such as rainfall, temperature, wind, etc. This study reports that the rate of carbon sequestration in Sundarbans was 17.21 Mg C ha−1 yr−1, which corresponds to 62.6 Mg ha−1 yr−1 CO2. High carbon stocks, carbon sequestration, and litterfall production rate in Sundarbans demonstrate the significance of mangrove species and Sundarbans in the global carbon budget. This information can be used in species selection for plantation, species conservation, and ecosystem management purposes at the regional and global levels.

Adjusting xylem anatomy and growth to inter-annual climate variability in two Fabaceae species (Centrolobium microchaete, Cenostigma pluviosum) from Bolivian dry tropical forests

Climate-growth relationships are strong in seasonally dry tropical forests (SDTFs). To better understand the ecological processes controlling these relationships we need to assess the long-term responses of wood anatomy and radial growth to year-to-year climate variability. We assessed how wood-anatomical traits (mean vessel area –MVA– and vessel density –VD–, percentage of conductive area –CA–, xylem-specific estimated hydraulic conductivity –Ks–) and growth responded to local climate (mean temperature, total precipitation, estimated moisture) variability and teleconnections (Pacific Decadal Oscillation) between 1970 and 2011 in two Fabaceae tree species (Centrolobium microchaete and Cenostigma pluviosum) coexisting in a Bolivian SDTF. We found that C. microchaete produced wider vessels and was more responsive to both local climate conditions and teleconnections than C. pluviosum. In C. microchaete VD positively responded to average temperature in the late-wet season and in the previous dry season, and CA and Ks were higher in years with warmer wet and previous early-dry seasons, as well as in years with higher PDO values. These responses were independent from ring-width variability only for C. microchaete. For C. pluviosum, vessel chronologies were more responsive to local temperature variability, and only MVA and CA positively and negatively responded to moisture in the early-dry and the previous dry seasons, respectively. Our results show that wood hydraulic structure in SDTFs is responsive to climate fluctuations. The combined study of ring width and wood anatomy allows having a more complete picture of the influence of climate on growth, particularly in species as C. microchaete which show low collinearity of tree-ring width and wood plasticity in response to climate variability.

Yield of irrigated rice affected by asymptomatic disease in a long-term intensive monocropping experiment

Sustained high yields of rice (Oryza sativa L.) are required in intensively cropped, irrigated systems to ensure food security and avoid expansion of cultivation into natural ecosystems. We examined whether good management practices and adapted cultivars could maintain high yields during 15 years (2001–2015) of continuous rice cultivation with three crops per year in the dry season (DS), early wet season (EWS), and late wet season (LWS). Results are for the highest-yielding fertilizer N rate of 195 kg N ha–1 in DS and 90 kg N ha–1 in EWS and LWS at the long-term continuous cropping experiment (LTCCE) in the Philippines. Our study addressed two critical questions remaining after previously reported research in the LTCCE: Can DS yield be sustained at >80 % of the climate- and genotype-specific yield potential, and can yield be increased in wet seasons? Management in DS, when cropping was synchronized with surrounding fields, controlled diseases and maintained yield at >80 % of simulated yield potential during 15 years. In EWS and LWS, when cropping was not synchronized with surrounding fields, tungro viruses were transmitted by insects from surrounding fields into the experiment. Management and adapted cultivars within the experiment did not prevent yield loss associated with reduced spikelet filling, which was attributed largely to tungro disease. In EWS, when planting was earlier than surrounding fields, yields were about 60–80 % of yield potential. In LWS, when planting was later than surrounding fields, yields declined to <65 % of yield potential. Enzyme-linked immunosorbent assay confirmed high infection in EWS and LWS with rice tungro spherical virus, which was not accompanied by symptoms of plant yellowing and stunted growth. In DS, when tungro was negligible, good management with adapted cultivars consistently minimized yield loss from nutrient deficiencies, soil problems, pathogens, and pests. However, good management with adapted cultivars could not maintain a small yield gap when tungro viruses were transmitted from infected surrounding fields into the experiment. In such case, closing the yield gap requires management interventions to reduce the pathogen and vector in surrounding fields. Negligible visible symptoms on most tungro-infected plants highlight the ease with which a biotic stress can be overlooked in experiments and growers’ fields.

A progressively wetter early through middle Holocene climate in the eastern lowlands of Guatemala

Climate records from Central America and the Caribbean region reveal considerable spatiotemporal complexity in precipitation variability, with multiple hypotheses explaining the likely ocean-atmosphere processes influencing precipitation in the region. Here we report on findings from a 760-cm long sediment core from Lake Izabal, eastern Guatemala that affords insight on regional hydroclimate change over the last ∼9,500 years. We utilized a radiocarbon-based age-depth model integrated with lithological, XRF elemental abundances, and principal component analyses to infer changes in erosion/precipitation, lake productivity, and lake water chemistry. Abundance of elements commonly associated with terrigenous sources increase from the early to the latest mid-Holocene, from ca. 9,500 to ca. 4,800 calibrated years before present (cal yr BP), suggesting a progressive increase in erosion/precipitation. This is followed by relatively stable and high erosion/precipitation conditions until ca. 1,200 cal yr BP, with an abrupt decrease in erosion/precipitation ∼1,200 years ago. Comparison of the Izabal record with other paleoclimate records from Central America and the Caribbean region indicates substantial heterogeneity in hydroclimate, even across relatively short distances, likely due to a combination of topographic complexity and the combined influences of Atlantic and Pacific basin ocean-atmosphere dynamics. Our results suggest that the progressive increase in boreal autumn insolation throughout the middle and late Holocene may have driven an increase in Caribbean sea-surface temperatures (SST) during the late wet season, leading to increased moisture availability through enhanced evaporation and greater precipitation amounts associated with zonal convergence and orographic uplift along the eastern coast of Central America. However, other nearby records demonstrate hydroclimate changes that are at least partially at odds with the Izabal record, indicating that the modern SST relationships with atmospheric circulation, including Intertropical Convergence Zone dynamics, and precipitation alone cannot be used as a framework for explaining hydroclimate variability across Central America during the Holocene.

Effects of land use change, wetland fragmentation, and best management practices on total suspended solids concentrations in an urbanizing Oregon watershed, USA

While many different watershed management strategies have been implemented to improve water quality, relatively few studies empirically tested the combined effects of different strategies on water quality in relation to land cover changes using long-term empirical data at the sub-basin scale. Using 10 years of total suspended solids (TSS) data, we examined how the conversion of wetland, wetland fragmentation, beaver dams, and Best Management Practices (BMPs) affect wet season TSS concentrations for the 25 monitoring stations in the Tualatin River basin, USA. Geographic information systems, FRAGSTATS, and correlation analysis were used to identify the direction of land cover change, degree of wetland fragmentation, and the strength of the relationship between TSS change and explanatory variables. Improvement in TSS concentrations was tightly coupled with the aggregation of wetlands, presence of beaver dams, particularly during the mid-wet season when flows were highest. Other BMPs effectively reduced TSS concentrations for the early and late-wet seasons when flows were not as high as in the middle wet-season. Aggregated wetlands were more effective for improving water quality than smaller disaggregated wetlands of similar total area when combined with the presence of beaver dams and BMPs. These findings offer important scientific and practical implications for management of urbanizing watersheds that seek to achieve the dual goals of improving environmental quality and land development.

Environmental Factors Affecting Birth Weight And Litter Size In Yankasa Sheep

Records on 1634 lambings of a Yankasa sheep flock collected from 1983 to 1990 were used to determine the effects of parity, litter size, sex, season and year of birth on birth weight, and that of parity, season and year of birth on litter size respectively. Least squares means (± s.e.) for birth weight and litter size were 2.49±0.013kg and 1.22±0.010 respectively. Birth weight was significantly (P&lt;0.01) affected by parity, sex, litter size and season of birth. Lambs born in the late wet season had higher birth weights than those born in other seasons. Also, male and single lambs were heavier at birth than female and twin lambs. Litter size was significantly (P&lt;0.01) affected by parity, season and year of birth. Late wet season lambing had lower litter size than other seasons. The repeatability estimates for birth weight and litter size were 0.19±0.028 and 0.01±0.032 respectively while phenotypic correlation between the two traits was -0.249.

SEASONAL EFFECTS ON OESTRUS PATTERNS AND PROGESTERONE PROFILES OF YANKASA EWES OF DIFFERENT AGE-GROUPS IN THE SUB-HUMID TROPICS

Oestrus patterns and serum progesterone profiles of 10 adult and 10 yearling Yankasa ewes were investigated in the late hot-dry and late-wet seasons in the subhumid tropical climate of Zaria, Nigeria. The proportions of ewes which came on heat once, twice or thrice within the experimental periods in the late hot-dry and late-wet seasons were 25, 15 and 0%, and 5, 10 and 85% respectively, while mean oestrous cycle length was significantly longer (P&lt;0.001) in the hot-dry season than in the late-wet season (30.9 vs 18.4 days) due to the higher incidence of anoestrus in the former. However, the mean duration of oestrus was not affected by season. Mean serum progesterone levels were significantly (P&lt;0.05) higher in the late-wet season than in the late hot-dry season (1.57 vs 0.52 ng/ml). However, there was a highly significant (P&lt;0.001) interaction between season and age group in mean serum progesterone levels due to a relatively greater depression in progesterone levels in yearling ewes during the hot-dry season compared with adult ewes. The observed disruptions in the oestrus cycle and serum progesterone levels of the ewes in the hot-dry season confirm the adverse effect of heat stress on the reproductive behaviour of ewes.

Milk yield, composition and their correlated relationships in some selected indigenous breeds of cattle in late wet season of Adamawa state, Nigeria

There is need for characterization of performances of cattle breeds in relation to milk yield and composition particularly in Adamawa State where seasonal fluctuations in climatic elements can affect livestock resilience. This study was carried out to evaluate the breed variation in milk yield and composition of some selected breeds of Nigerian indigenous cattle in Adamawa State in the late wet season (August-October). The milk of 20 cows each from four breeds (Bunaji, Rahaji, Adamawa Gudali and Bokoloji) was sampled for milk yield and composition analysis three times within the season. Milk was analysed for its composition. Breed significantly (p&lt;0.05) influenced the milk component evaluated. Bunaji was superior in milk yield (1.92), fat yield (5.73) and total solid non-fat (4.59). Rahaji was superior in phosphorus (410), sodium (61.01) and iron (3.16) while Bokoloji was superior in protein (4.98) and calcium (721). For the correlated relationships between the milk components evaluated in different breeds, there was a significant (p&lt;0.05-0.01; r = -0.89 to 1.00) correlation between milk components except (p&gt;0.05; r = -0.21 to 0.24) within various breeds. Zero relationship existed between milk yield and Fe in Adamawa Gudali (p&gt;0.05; r =0.00) while a perfect relation exists between milk yield and protein yield (p&gt;0.01; r = 1.00) in Rahaji, Adamawa Gudali and Bokoloji and between protein yield and fat yield (p&gt;0.01; r = 1.00) in Bunaji and Bokoloji.For the pooled correlated responses, there was significant (p&lt;0.05-0.01; r = -0.95 to 0.99) relationships between most milk components. It was therefore concluded that Bunaji had the highest milk yield, Bokoloji was best in milk protein and fat contents while Rahaji was best in mineral contents. Also, correlated relationship between milk components should be maximized in formulating a selection programme for improvement of milk in Nigerian indigenous cattle.

Efficacy and economics of integrated weed management in okra (Abelmoschus esculentus (L.) Moench)

Abstract Weed management is one of the most important and expensive steps in okra production. Field experiments were therefore conducted in the early and late wet seasons of 2015 to evaluate the effectiveness and profitability of weed management using hoe weeding, herbicides or their combination in okra production. Propaben or butachlor at 2.0 kg a.i. (active ingredient) ha–1 followed by (fb) supplementary hoe weeding (shw) at 6 weeks after sowing (WAS) significantly (P &lt; 0.05) reduced weed density and biomass with subsequent increase in okra fruit yield similar to three hoe weedings and better than two hoe weedings or either herbicide applied alone in both early and late wet seasons. Although three hoe weedings provided the highest okra fruit yield (3590 and 4102 kg ha–1) and total revenue ($991.7 and $1699.7 ha–1), the gross margin ($186.4 and $931.6 ha–1) and cost-benefit ratio (0.2 and 1.2) obtained were lower than those obtained with herbicide treatments. Highest gross margin ($470.8 and $1224.9 ha–1) and cost-benefit ratio (1.2 and 3.0) in the early and late wet seasons, respectively, were achieved with propaben at 2.0 kg a.i ha–1 fb shw at 6 WAS. The results of this study suggest that integrated weed management with propaben followed by supplementary hoe weeding will improve weed control, productivity and profitability of okra. Multiple hoe weeding, however, did not guarantee highest profit but rather increased the cost of production.

Climatic Records to Aid Urban Planning and Improvement of Thermal Comfort in Buildings: A Case Study on Agege-Lagos, Nigeria

The thermal comfort in a building enables the spread of communicable diseases or initiate skin irritations amongst others. Most models on thermal comfort have proven to be localized in the application, as thermal comfort depends on the climatic condition over a geographical area. Based on the above, there is the need to adopt the local method to understand the thermal comfort indexes in Agege. Thirty-nine years dataset (1980-2018) of temperature, relative humidity, wind speed, and wind direction was obtained from MERRA-NASA database for Agege, Lagos Nigeria. The dataset was divided into early dry season (i.e. September, October, November- SON), late dry season (i.e. December, January February-DJF), early wet season (i.e. March, April, May – MAM) and late wet season (i.e. June, July, August-JJA). It was observed that the effect of climate change was significant. Hence, it is recommended that the inhabitants of the area should go green by planting trees and shrubs. Also, there is a need to modify the urban plan to decongest the area.