Biological, ecological and agronomic significance of plant phenolic compounds in rhizosphere of the symbiotic legumes

Phenolics are low molecular compounds ubiquitous in all tissues of higher plants with great significance in plant development. Our understanding of some phenolic compounds in the last few decades has greatly improved. However, their biological, ecological and agronomical significance in therhizosphere of most symbiotic legumes is much less clear. Further understanding of these biomolecules will increase our knowledge of their contribution in soil and water conservation, weed management,mineral element nutrition, their impact as signal molecule in certain symbiotic relationships, and their role as defence molecules against soil pests and pathogens. This article reviews the bioecological and agronomical significance of phenolic compounds in the rhizosphere of a few studied symbiotic legumes and other plants

Reclamation of sodic soils in northern Tanzania, using locally available organic and inorganic resources

Sodic soils could produce useful maize (Zea mays L.) crop yields if reclaimed by appropriate techniques. A field experiment was conducted on the selected lowlands of northern Tanzania using a randomised complete block design to study the effectiveness of supplying gypsum (CaSO4.2H2O) or farmyard manure (FMY) alone or both mixtures on the reclamation of a sodic soil. Sodic soil and FYM were characterised to establish their quality status before any intervention was introduced. The treatment used included: control, FYM alone (25 t ha-1), FYM (25 t ha-1) combined with gypsum (12.5 t ha-1) and gypsum alone (12.5 t ha-1). The treatments were replicated four times. Selected numbers of soil physical and chemical properties were then investigated. Results from our study revealed that regardless of the amendments used, maize yield and all soil physical and chemical properties tested were improved in Year 2 (Y2) relative to Year 1 (Y1). Our results also showed that combining FYM with gypsum significantly (p0.05) improved pH, electrical conductivity of the saturated paste (ECe), exchangeable sodium percentage (ESP), infiltration rate (IR), osmotic potential (OP) and available water capacity (AWC) of sodic soils. The FYM was the second-best treatment in the improvement of pH, ESP and EC whereas gypsum was second in the improvement of ESP, IR and maize yield

Soil Fertility Characterization in Mvumi and Mbogo - Komtonga Irrigation Schemes in Kilosa and Mvomero Districts, Morogoro Region, Tanzania.

Soil samples from three (3) mapping units in Mvumi and four (4) mapping units in Mbogo Komtonga representing two irrigation schemes in Kilosa and Mvomero Districts in eastern Tanzania were collected and analyzed for different mineral elements. Using zigzag sampling techniques, 9 composite samples with three replicates were collected at depth 0 – 30 cm from the delineated pedogeomorphic units at a radius of 20 m around the soil pits. Soil samples from each soil type were bulked, thoroughly mixed, sub sampled to obtain a representative composite sample, packed and sent to Mlingano National Soil Service laboratory (NSS), Tanga, Tanzania for the determination of physical chemical fertility indicators. The data showed overall significant (P ≤ 0.05) difference in fertility status in the selected irrigation schemes. The pH of top soils in Mvumi and Mbogo - Komtonga irrigation schemes ranged from 4.4 to 6.3. These were rated as extremely and/or strongly acid to slightly acid. Of the total area studied in Mvumi and Mbogo Komtonga irrigation schemes, 25.5 % is slightly acid, 40.2 % is medium acid, 31.0 % is extremely acid and 3.3 % extremely acid. Similarly, results of organic carbon (OC) determination from the top soil (0 - 30 cm) samples ranged from 26.6 g kg-1 to 51.8 g kg-1. This corresponds to 45.7 g kg-1 to 89.0 g kg-1 SOM in both irrigation schemes. The data showed that % OC in all irrigation schemes was very high in 92.2 % and high in 7.8 % of the surveyed areas. The results show that the top soils of all the surveyed areas in Mvumi and Mbogo - Komtonga irrigation schemes had N in the range of 1.2 to 3.8 mg kg-1, 48.7 % had N below the critical limits whereas 51.3 % were above the same. Available P in both schemes range from 0.68 – 6.53 mg kg-1. Based on the generally accepted threshold P level, all the observed P values in Mvumi and Mbogo - Komtonga respectively were considered to be below the critical range. Cation exchange capacity values in most topsoil in Mvumi and Mbogo - Komtonga irrigation schemes were rated as medium or high to very high. These values range between 27.0 – 54.6 cmol (+) kg-1 and were rated as medium in 25.5 %, high in 35.3 % and very high in 39.2 % of the total surveyed areas. Exchangeable Ca in the topsoil of Mvumi and Mbogo - Komtonga irrigation schemes ranged from 3.99 – 31.3 cmol (+) kg-1. These were rated as medium in 0.96 %, high in 34.3 % and very high in 70.2 %. Based on the critical limits, MV – Pa3 in Mvumi is likely to be deficient of Ca2+ for most crops as it lies below the proposed critical limits. Exchangeable Mg2+ in the irrigation schemes range from 0.28 – 5.07 cmol (+) kg-1, rated as high to very high. These data suggests that all the MUs except for MV – Pa3 in Mvumi and Mbogo - Komtonga have sufficient Mg2+ supplies for crop growth. Potassium in Mvumi and Mbogo – Komtonga irrigation schemes, range from 0.61 - 2.97 cmol (+) kg-1. These were rated as medium in 64.3 % to very high in 35.7 % of the total area. The data shows that in Mvumi K is unlikely to respond similar to Mbogo – Komtonga. The results of Naexch indicates that the levels of Na+ in the top soils corresponds to 0.15 – 0.47 cmol (+) kg-1 soil in both irrigation schemes. These values were rated as low in 16.4 % and medium in 83.6 % and the corresponding ESP range from 0.5 – 2.2 % in Mvumi considered non-sodic. These results suggest that the surveyed areas have no threat to sodicity problems and the major soil fertility constraints were soil reaction (pH), Nitrogen (N), Phosphorus (P) and poor Soil Organic Matter (SOM)

Low - Cost Irrigation Technology, in the Context of Sustainable Land Management and Adaptation to Climate Change in the Kilimanjaro Region

Unsustainable land management and poor adaptation to climate change limits agricultural production in different districts in Kilimanjaro Region. The aim of this study was to train farmers on different aspects of Sustainable Land Management (SLM), improve water use efficiency (WUE) through rehabilitation of traditionally managed irrigation schemes and installation of precision irrigation systems in order to compare their performance without such systems and to assess the impact of the interventions on crop yield and water use productivity. Data were collected during land survey and farmers training in selected areas in Kilimanjaro Region using land survey and farmers training techniques. The data showed increased area under irrigation, improved crop yield, farmer income, water use efficiency and production and productivity in drip irrigation system demonstrated plots compared with furrow or gravity irrigation methods. Improved intake and main canal in Ngalachu irrigation scheme had overall all measured parameters but less compared with drip irrigation. Water saved by drip irrigation was greater by between 33 % and 50 % compared with furrow irrigation methods. The data also showed that crop yields and total revenue in drip irrigation were greater by between 25 % and 60 % and 167 % and 400 % respectively compared with the furrow irrigation methods. These results suggest that farmers using drip irrigation systems were able to realize skills and knowledge, less water loss and greater WUE, higher crop yields, higher incomes compared with places without drip irrigation systems or furrow irrigation methods. However, more time is needed to test these technologies in the field so as to have more meaningful results. It is recommended that the technologies as well as rehabilitation of traditional irrigation schemes be up scaled to a larger area and assess their impact to farmers. Targeted agronomic practices such as the choice of appropriate crop/cultivar (i.e. high value crops) for a specific environment as well as planting and harvesting times, adequate plant nutrition, soil management, and weed control should be observed by both farmers and extension staff since such agricultural practices can significantly contribute to improve WUE and farmers income through increased gross margins. Keywords: Climate change, water use efficiency, canal, total revenue, water harvesting, land, managemen

Chromium Adsorptive Removal From Industrial Wastewater Using Various Reactive Media- A Mini Review

Effluents from industries frequently contain a variety of chromium ions such as hexavalent chromium and trivalent chromium which can adversely pose threats to terrestrial and aquatic life. Hexavalent chromium is more toxic than trivalent chromium thus needs to be removed from effluents.  Adsorption is a water and wastewater treatment technology which plays a significant role in the removal of heavy metals including chromium from effluents. In this review paper, the performance of distinct inexpensive reactive bio adsorbents and other adsorbents used by different researchers was reviewed. The findings from different studies indicated that most of the adsorbents for the removal of chromium are technically uncomplicated and mostly had outstanding performance. Factors frequently and seldom used for selection of best media for adsorption were also reviewed. Although many researchers have proven that most of the media have outstanding performance, there is still paucity of information on the effects of practical issues such as mechanical strength of media, its toxicity and leachability, abrasion on adsorption capacity. Findings also shown that sodium hydroxide is the best regeneration eluent. The findings of different studies in this review have demonstrated that different low-cost bio adsorbents can be employed in industrial wastewater treatment processes to remove chromium

Soil acid phosphomonoesterase activity and phosphorus forms in ancient and post-agricultural black alder [Alnus glutinosa (L.) Gaertn.] woodlands

Black alder, an N-fixing tree is considered to accelerate the availability of phosphorus in soils due to the increased production of phosphatase enzymes, which are responsible for the P release from the litter. Acid phosphatase activity plays a pivotal role in organic P mineralization in forest soils and in making P available to plants. In order to check whether Alnus glutinosa stimulates acid phosphomonoesterase (PHACID) activity, we compared enzyme activities, total P concentration (PTOT), plant-available P (PAVAIL), organic P (PORG) and inorganic P (PINORG), and organic matter content in 27 ancient and 27 post-agricultural alder woods (the latter ones representing different age classes: 11-20, 21-40 and 41-60 years) of soil samples taken from the litter and the mineral layers. Phosphomonoesterase activity, organic matter, PTOT, PINORG and PORG concentrations were significantly higher in ancient alder woods than in the soils of post-agricultural forests. Significant differences in the acid phosphatase activity, organic matter and PAVAIL concentration were noted between the litter and mineral layers within the same forest type. In recent stands the amount of organic matter and phosphatase activity increased significantly with the age of alder stands, although only in the mineral layer of their soils. Phosphomonoesterase activity, organic matter and PAVAIL content were higher in a litter layer and decreased significantly at a mineral depth of the soil. The acid phosphatase activity was significantly correlated with organic matter content in both ancient and recent stands. There was no significant relationship between PHACID activity and any P forms

Can sub-Saharan Africa feed itself?

Although global food demand is expected to increase 60% by 2050 compared with 2005/2007, the rise will be much greater in sub-Saharan Africa (SSA). Indeed, SSA is the region at greatest food security risk because by 2050 its population will increase 2.5-fold and demand for cereals approximately triple, whereas current levels of cereal consumption already depend on substantial imports. At issue is whether SSA can meet this vast increase in cereal demand without greater reliance on cereal imports or major expansion of agricultural area and associated biodiversity loss and greenhouse gas emissions. Recent studies indicate that the global increase in food demand by 2050 can be met through closing the gap between current farm yield and yield potential on existing cropland. Here, however, we estimate it will not be feasible to meet future SSA cereal demand on existing production area by yield gap closure alone. Our agronomically robust yield gap analysis for 10 countries in SSA using location-specific data and a spatial upscaling approach reveals that, in addition to yield gap closure, other more complex and uncertain components of intensification are also needed, i.e., increasing cropping intensity (the number of crops grown per 12 mo on the same field) and sustainable expansion of irrigated production area. If intensification is not successful and massive cropland land expansion is to be avoided, SSA will depend much more on imports of cereals than it does today

Perceived quality of maternal health care among pregnant women and mothers attending Morogoro rural district health facilities in Tanzania

Objectives: The major objective of the study was to determine the perceptions of pregnant women and mothers regarding quality of maternal health services including their level of satisfaction on health care services received.Methods: A cross-sectional descriptive study was conducted in Morogoro Rural District involving 283 pregnant women and mothers. We used interview schedules and exit interviews to collect data. In order to assess both the levels of satisfaction and perceived quality of care, we used Likert scale of 1-5 points. Analyses were based on proportions and a chi-square test was applied to assess the association between dependent and independent categorical variables.Results: The majority, 75%, of pregnant women and mothers reported the quality of maternal health care to be acceptable. Positive perception on behaviors of health care providers was rated high, ranging between 86% and 96% of all study participants. Despite affirmative perceptions, some participants reported negative behaviors of the health care providers to be disappointing.Conclusion: With the unsatisfactory current situation of health care services in Tanzania especially in rural health facilities, this study suggests that the quality of maternal healthcare perceived by pregnant women and mothers is acceptable. It is also important is to recognize perceptions of women regarding quality of maternal health care and their levels of satisfaction.Key Words: Maternal health, Perception, Rural, Satisfaction, Tanzani