Response of maize to phosphorus in sole maize and maize-pigeonpea cropping system in semi-arid areas of Tanzania

Estimating crop response to fertilizer application and identification of effective fertilizer materials is important for plant nutrient management and in sustaining soil fertility. Unlike other agro-ecological zones, no fertilizer recommendations have been established for the semi-arid zones in Tanzania. This could be due to the fact that semi-arid areas are regarded as marginal land for agricultural production. To address this gap, field experiments were carried out to establish phosphorus (P) fertilizer rates and identify the effective P source for semi-arid areas of Kongwa and Kiteto districts in a sole maize and maize-pigeonpea cropping system. Assessment of soil fertility status on experimental sites was carried out. Triple Super Phosphate (TSP) fertilizer was used to test various application rates: 0, 7.5, 15, 30, 45 and 60 kg P ha-1. For P-source triall, Minjingu Mazao, Minjingu hyper phosphate and TSP were tested at 0 and 30 kg P ha-1 for each fertilizer material. Sole maize or intercropped with pigeonpea was used as the test crop in two fertilizer trials. The treatments were arranged in a Randomized Complete Block Design (RCBD) with three replications. Soils in the study sites were deficient of P, N and Ca; and had very low organic matter contents. Compared to the control, the fertilizer treatments had higher yield across sites and cropping system. The 15 kg P ha−1 fertilizer rate increased the grain yield by 38 to 49% in sole maize and 55 to 60% in maize-pigeonpea intercropping system at Njoro and 51 to 54% in sole maize and 44 to 46% in maize pigeonpea intercropping system in Moleti. Maize yield obtained with 15 kg P ha−1 was equivalent to the maximum yield obtained under 30 kg P ha−1 fertilizer rate. Maize yield obtained after 30 kg P ha-1 fertilizer rate declined slightly possibly reflecting sufficiency level of P. These results suggest that 15 kg P ha-1 P is the agronomic P fertilizer rate for maize production under sole maize and maize-pigeon pea intercropping system in semi-arid areas of Kongwa and Kiteto districts, Therefore, application of this particular rate in maize and maize-pigeon pea cropping system may be an option for the marginal farmers in the region as farmers may reduce the application rate by 50% without losing yield significantly. Maize grain yield obtained with Minjingu Mazao fertilizer treatment was similar to the yield obtained with TSP fertilizer in Moleti site (3.6 vs. 3.7 t ha-1) and Njoro site (3.9 vs. 4.2 t ha-1). High response of maize to Minjingu mazao is attributed to slightly acidic soil condition, starter N, calcium and fortified micronutrients in this fertilizer material. Thus farmer may use Minjingu mazao or TSP as they are equally suitable P sources in maize production in semi-arid areas of Kongwa and Kiteto districts

Estimation of local and external contributions of biomass burning to PM2.5 in an industrial zone included in a large urban settlement

A total of 85 PM2.5 samples were collected at a site located in a large industrial zone (Porto Marghera, Venice, Italy) during a 1-year-long sampling campaign. Samples were analyzed to determine water-soluble inorganic ions, elemental and organic carbon, and levoglucosan, and results were processed to investigate the seasonal patterns, the relationship between the analyzed species, and the most probable sources by using a set of tools, including (i) conditional probability function (CPF), (ii) conditional bivariate probability function (CBPF), (iii) concentration weighted trajectory (CWT), and (iv) potential source contribution function (PSCF) analyses. Furthermore, the importance of biomass combustions to PM2.5 was also estimated. Average PM2.5 concentrations ranged between 54 and 16 μg m−3 in the cold and warm period, respectively. The mean value of total ions was 11 μg m−3 (range 1–46 μg m−3): The most abundant ion was nitrate with a share of 44 % followed by sulfate (29 %), ammonium (14 %), potassium (4 %), and chloride (4 %). Levoglucosan accounted for 1.2 % of the PM2.5 mass, and its concentration ranged from few ng m−3 in warm periods to 2.66 μg m−3 during winter. Average concentrations of levoglucosan during the cold period were higher than those found in other European urban sites. This result may indicate a great influence of biomass combustions on particulate matter pollution. Elemental and organic carbon (EC, OC) showed similar behavior, with the highest contributions during cold periods and lower during summer. The ratios between biomass burning indicators (K+, Cl−, NO3−, SO42−, levoglucosan, EC, and OC) were used as proxy for the biomass burning estimation, and the contribution to the OC and PM2.5 was also calculated by using the levoglucosan (LG)/OC and LG/PM2.5 ratios and was estimated to be 29 and 18 %, respectively

Cooking fuels and respiratory symptoms in kitchen workers in Morogoro Municipality, Tanzania

Few studies on a possible association between cooking fumes from different fuels and respiratory diseases other than cancer have been reported earlier. In the present study, an attempt was made to find out various respiratory symptoms in 360 kitchen workers using different cooking fuels. The study was conducted between October 2009 and March 2010 and consisted of 234 females and 126 males. The kitchen workers from 104 selected kitchens in hotels, fast food restaurants, institution, food vendors and in households of the general population were interviewed using a questionnaire. Information on the presence of dry cough, productive cough, running nose, irritation of nose or eyes, and chest pain in connection with work were asked. The overall respiratory symptoms were observed in 68.9% of the surveyed kitchen workers. With the exception of dry cough, females encountered 61.54% of productive cough, 57.69% running nose, and 71.28% irritation of nose or eyes. Chest pain and irritation of nose and eyes were more common in kitchen workers that use biomass fuel, charcoal and/or kerosene than other cooking fuels. The results of the study indicate a significant relationship (p < 0.05) between use of different cooking fuels and respiratory symptoms. However, further studies are needed to support the present results.© 2010 International Formulae Group. All rights reserved.Keywords: Kitchen work; cooking fuels; Respiratory infection; Cook

Land-Use–Land Cover Changes in the Urban River’s Buffer Zone and Variability of Discharge, Water, and Sediment Quality—A Case of Urban Catchment of the Ngerengere River in Tanzania

The physical integrity of the Ngerengere River and its three tributaries drains within Morogoro Municipality were evaluated by assessing the variations in land-use–land cover (LULC) in the river’s buffer zone, the discharge, and the contamination of river water and sediment from nutrients and heavy metals. Integrated geospatial techniques were used to classify the LULC in the river’s buffer zone. In contrast, the velocity area method and monitoring data from the Wami-Ruvu Basin were used for the discharge measurements. Furthermore, atomic absorption spectrophotometry was used during the laboratory analysis to determine the level of nutrients and heavy metals in the water and river sediment across the 13 sampling locations. The LULC assessment in the river’s buffer during the sampling year of 2023 showed that bare land and built-up areas dominate the river’s buffer, with a coverage of 28% and 38% of the area distribution. The higher discharge across the sampling stations was in the upstream reaches at 3.73 m3/s and 2.36 m3/s at the confluences. The highest concentrations of heavy metals in the water for the dry and wet seasons were 0.09 ± 0.01, 0.25 ± 0.01, 0.03 ± 0.02, 0.73 ± 0.04, 4.07 ± 0.08, and 3.07 ± 0.04 mg/L, respectively, for Pb, Cr, Cd, Cu, Zn, and Ni. The order of magnitude of the heavy metal concentration in the sediments was Zn > Ni > Cr > Cu > Cd > Pb, while the highest NO2−, NO3−, NH3, and PO43− in the water and sediment were 2.05 ± 0.01, 0.394 ± 0.527, 0.66 ± 0.05, and 0.63 ± 0.01 mg/L, and 2.64 ± 0.03, 0.63 ± 0.01, 2.36 ± 0.01, and 48.16 ± 0.01 mg/kg, respectively, across all sampling seasons. This study highlights the significant impact of urbanization on river integrity, revealing elevated levels of heavy metal contamination in both water and sediment, the variability of discharge, and alterations in the LULC in the rivers’ buffer. This study recommends the continuous monitoring of the river water quality and quantity of the urban rivers, and the overall land-use plans for conserving river ecosystems