Mangrove ecosystem is unique in nature due to the combination of Halophytic plants, animals, birds and aquatic organisms. Such wetland ecosystems possess rich nutrition status that contributes rich bio resources to aquatic flora and fauna. Brackish water within the ambit of Pichavaram plays a pivotal role on growth and development of mangrove community. A study was undertaken to understand the surface water dynamics quality parameters in Pichavaram Estuary. Analysis of water quality parameters was assessed for the period of November 2012. Adequate care was taken to cover all tidal regimes (i.e.) (i) Inlet: the point where the principal feeder opens into the estuary; (ii) Center: the point that gives the general water quality of the estuary; (iii) Outlet: the place where the overflow occurs. Study sites from which samples were collected, were identified adjoining the region of Parangipettai Vellar Estuary and Pichavaram mangrove forest. Ten surface water samples were collected. These were analyzed for physico-chemical parameters such as temperature, pH, salinity, dissolved oxygen and total dissolved solids vary significantly among the three regions. All studied parameters were spatially interpolated in GIS environment to understand the distribution of individual nutrient in the ecosystem. The results of the statistical analysis were subjected to cluster analysis for grouping parameters based on similarity and dissimilarities. Individual parameter values were overlaid on the LANDSAT imagery to understand spatial representation of water quality with respect to bio-physical value of the mangrove ecosystem.
Agricultural soil quality is drastically affected by modern human activities. This study evaluates sole and combined effect of three agro-wastes namely: - rice husk Ash (RHA), rice husk dust (RHD) and poultry manure (PD) on soil fertility nutrient content and grain yield of maize on an Ultisol in Southeast Nigeria. Single and combined effects of the materials were investigated at application rates of 10t/ha for sole PD and RHD, 5 t/ha for sole RHA, 5 t/ha PD + 5 t/ha RHD, 5 t/ha PD + 2.5 t/ha RHA and 3.33 t/ha PD + 3.33 t/ha RHD + 1.67 t/ha RHA with 0 t/ha(control) giving seven treatments. The soil studied was low in pH, organic carbon (OC), total nitrogen, available phosphorous, exchangeable potassium and cation exchange capacity. The soil parameters studied include soil pH, OC, Total nitrogen, exchangeable bases, CEC, EA and available phosphorous while the grain yield of maize was also measured after harvest. Results showed that the amendments significantly improved the soil pH, organic carbon, exchangeable Na, K, Ca and Mg, while the total nitrogen was not affected significantly. Exchangeable acidity was drastically reduced by the amendments, while the available phosphorous was significantly increased by the application of treatments. Maize grain yield was also significantly increased by the treatments applications. The integrated application especially at 5 t ha-1 poultry manure and 5 t ha-1 rice husk dust increased maize yield and most soil nutrient elements higher than other combinations in the study.
Developing nitrogen use efficient (NUE) genotypes of wheat could reduce crop N fertilizer requirement. However, selection for NUE alone can be difficult and less efficient than associating it with one or more of selection criteria. The aim of this study was to determine selection criteria for improving NUE in wheat genotypes and their F1 and F2 progenies under contrasting N environments. The results of this study indicated that high nitrogen uptake efficiency (NUPE), grain yield/plant (GYPP), grains/spike (GPS), spikes/plant (SPP), and grain protein content (GPC) of parents, high NUPE, GYPP, biological yield/plant (BYPP), GPC and GPS of F1's and high NUPE, harvest index (HI), BYPP, SPP, GPC and GPS of F2's have significant and strong correlation coefficients with high nitrogen use efficiency (NUE). It is observed that NUPE is commonly correlated with NUE in all studied genotypes (parents, F1's and F2's). Similarly, GPS is also strongly correlated with NUE. Moreover, SPP is strongly correlated with NUE in parents and F2's. A negative and significant correlation existed between NUPE and NUTE for parents under high-N (-0.82), F1's under high-N (-0.73) and low-N (-0.36) and F2's under high-N (-0.91) and low-N (-0.81). The traits NUPE, GYPP, SPP and GPS showed high heritability in narrow sense and could therefore be offered to wheat breeders for use in breeding programs as selection criteria for improving nitrogen use efficiency.
Declining soil fertility attributed to soil acidity is a major soil productivity problem in sub-Saharan Africa. A study was carried out in nine counties across the Kenya highlands, namely Meru, Embu, Kerugoya, Nyeri, Kiambu, Kinangop, Siaya, Busia and Eldoret, where the problems associated with soil acidity are prominent. The study aimed at assessing farmers’ awareness of soil acidity, and establishment of common acidity management practices following administration of structured questionnaires. From the information gathered through personal interviews via questionnaires, <37% of the farmers were attached to a farmers training group in all study sites; among them, <4% were aware of soil acidity problems and <8% had carried out chemical analysis of their soils. The farmers who had applied lime at least once on their farms were <3% in all sites. Most farmers (>80%) used both inorganic fertilizers and manure on their farms, with the majority using DAP, CAN and farmyard manure. On cultural soil fertility management, choice of subsequent crop was dictated by sustainability rather than cropping system like rotation. There was a significant (P<0.05) negative relationship between livestock keeping and soil fertility management, with <30% of the farmers returning crop residues back to the farm. Most of them fed crop residues to their livestock. Only 8% of the farmers incorporated crop residues into the soil. There was a significant (P≤ 0.05) positive correlation between education level and inorganic fertilizer use in crop production. Farmer’s age and maize yields correlated negatively with each other. Additionally, farmers’ training programmes and frequencies positively influenced choice of inorganic fertilizers and levels of application. Training is therefore one of the most significant issues affecting soil fertility management in the Kenya highlands. To further enhance the understanding of soil acidity and fertility management in Kenya highlands, farmers training should be prioritized.
Aims: The aim of this study was to compare the leaf traits and branching patterns between Acacia tortilis, Balanites aegyptiaca and Ziziphus mauritiana seedlings, three species occurring in the same range in the Sahel, a semi‑arid tropical area of Africa.
Study Design: Seeds used in this experiment were collected from a semi‑arid area (16°20’N, 15°25’W), from species growing in their natural range in the Sahel. Seeds were after transferred at the experimental site where they were germinated and grown in a common garden experiment, on an area of 1300 m².
Place and Duration of Study: The experimental site was located at around 400 km south of the seed origin (17°33'N, 14°55'W). The experiments were carried out between October 2002 and October 2004.
Methodology: The seedlings were watered three days a week from the beginning of the experiment until July 2004. Thereafter, seedlings were assessed at 11 months, 16 months old, and at 24 months after the seed germination date. In the assessment, we measured the length (LGU) and the number (NGU) of growth units, the number of nodes (Nnode), and leaves (Nleaf), and the single (Aleaf) and total (Afoliage) leaf areas.
Results: Following the water stress, Nleaf and Aleaf only decreased in A. tortilis, to tightly control the transpiration. Aleaf increased in B. aegyptiaca and Z. mauritiana, due to persistent leaves flushed before the water stress. Afoliage, NGU and Nnode were generally consistent, while LGU decreased in B. aegyptiaca. The defoliation in dry season despite the watering suggested an endogen control, allowing the species to escape harsh conditions in their natural range.
Conclusion: The study do not support the hypothesis according to which species naturally coexisting are likely to display similar trend in leaf traits and branching patterns in response to drought. The study has been limited to three weeks of water stress and deserves to be extending to provide more insight into traits pattern for a longer period of water stress.