DSpace Collection: Journal Articles

Introduction and Participatoryevaluation of Exotic Cultivars of Pepper (Capsicum Spp.) among Small Holder Farmers in South- Western Nigeria

2015-09-22T14:07:20Z

Title: Introduction and Participatoryevaluation of Exotic Cultivars of Pepper (Capsicum Spp.) among Small Holder Farmers in South- Western Nigeria Authors: kin Omotayo 1  , Claudia Ribeiro 2 , Anthony K. Oluleye 3 and Ayodele Fajin mi 4 Abstract: Pepper (Capsicum spp.) production by farmers in southwestern Nigeria is limited by low yield due to poor genetic potentials of most cultivars available, use of poor quality seeds, disease infestation, and poor managment practices among others. To overcome the constraints, some varieties of pepper developed at Embrapa Brazil and NIHORT Nigeria, were introducedfollowed bytraining of 1 00 small scale farmers . Participatory field demonstrations of the improved varieties of pepper were carried out to determine acceptability some of these pepp er varieties among f armers . T he two Brazilian sweet bell peppers (Z105 , Z103 ) singificantly outyielded the local variety (F102). Two of the Rhombus shaped vaireties introduced (Z106 and Z107) also recorded sifgnificantly h igher yield than t he local varieties. Famers‟ ranking of the varietiesindicates preference for all the exotic lines on all paramters . Based on the results , four Brazillian vareit ies, Z103, Z105, Z106 and Z107 we re selected for widespread promotion . Description: 3.3. Farmers ’ Ranking of Pepper Varieties Following the approach by Russell [7] famers were requested to rank all the pepper varieties introduced on three paramters which are yield, disease resistance and adoption potential (Table 3) after training the faemrs on idenrtiifcation of all these parameters . On all parameters, famers who were trained show preference for all the exotic varie ties for disease resitiance of Z108 var i ety. The ranking of all the varieties appear consistent among famrers based on percieved yield except for that same variety Z108 which was ranked low and this appears to affect farmers ranking of its adoption potentia l. Farmers who were trained differed singinicantly from those who were not trained in their ranking of some of the paprameters particularly on determin ation of disease severity (DS)

Effects of Subsetting by Carbon Content, Soil Order, and Spectral Classification on Prediction of Soil Total Carbon with Diffuse Reflectance Spectroscopy

2016-01-15T13:18:57Z

Title: Effects of Subsetting by Carbon Content, Soil Order, and Spectral Classification on Prediction of Soil Total Carbon with Diffuse Reflectance Spectroscopy Authors: Meryl L. McDowell, Gregory L. Bruland; Jonathan L. Deenik, Sabine Grunwald Abstract: Subsetting of samples is a promising avenue of research for the continued improvement of prediction models for soil properties with diffuse reflectance spectroscopy. This study examined the effects of subsetting by soil total carbon (Ct ) content, soil order, and spectral classification with k-means cluster analysis on visible/near-infrared and mid-infrared partial least squares models for Ct prediction. Our sample set was composed of various Hawaiian soils from primarily agricultural lands with Ct contents from <1% to 56%. Slight improvements in the coefficient of determination (R2 ) and other standard model quality parameters were observed in the models for the subset of the high activity clay soil orders compared to the models of the full sample set. The other subset models explored did not exhibit improvement across all parameters. Models created from subsets consisting of only low Ct samples (e.g., Ct < 10%) showed improvement in the root mean squared error (RMSE) and percent error of prediction for low Ct soil samples. These results provide a basis for future study of practical subsetting strategies for soil Ct prediction.

Spatial Distribution of PCB Dechlorinating Bacteria and Activities in Contaminated Soil

2016-01-15T13:19:29Z

Title: Spatial Distribution of PCB Dechlorinating Bacteria and Activities in Contaminated Soil Authors: Birthe V. Kjellerup, Piuly Paul; Upal Ghosh, Harold D. May; Kevin R. Sowers Abstract: Soil samples contaminated with Aroclor 1260 were analyzed for microbial PCB dechlorination potential, which is the rate-limitingstep for complete PCB degradation. The average chlorines per biphenyl varied throughout the site suggesting that different rates of in situ dechlorination had occurred over time. Analysis of PCB transforming (aerobic and anaerobic) microbial communities and dechlorinating potential revealed spatial heterogeneity of both putative PCB transforming phylotypes and dechlorination activity.Some soil samples inhibited PCB dechlorination in active sediment from Baltimore Harbor indicating that metal or organic contaminants might cause the observed heterogeneity of in situ dechlorination. Bioaugmentation of soil samples contaminated with PCBs ranging from 4.6 to 265 ppm with a pure culture of the PCB dechlorinating bacterium Dehalobium chlorocoercia DF- 1 also yielded heterologous results with significant dechlorination of weathered PCBs observed in one location. The detection of indigenous PCB dehalorespiring activity combined with the detection of putative dechlorinating bacteria and biphenyl dioxygenase genes in the soil aggregates suggests that the potential exists for complete mineralization of PCBs in soils. However, in contrast to sediments, the heterologous distribution of microorganisms, PCBs, and inhibitory contaminants is a significant challenge for the development of in situ microbial treatment of PCB impacted soils.

Land Application of Biosolids in the USA: A Review

2016-01-15T13:19:58Z

Title: Land Application of Biosolids in the USA: A Review Authors: Qin Lu, Zhenli L He; Peter J. Stoffella Abstract: Land application of biosolids has proven a cost-effective method of waste disposal by beneficially recycling organic matter and nutrients and improving soil quality; however, it may also pose potential threat to the environment and human health. The purpose of this paper is to provide information on recent research progresses and regulation efforts regarding land application of biosolids, including forms and types and nutrient values of biosolids, environmental and health concerns, and related best management practices (BMPs) of biosolids application, with emphasis on its land application in agriculture. More research and regulations are expected to minimize potential risks of biosolids land application, especially its long-term impacts.

Effects of Monoculture, Crop Rotation, and Soil Moisture Content on Selected Soil Physicochemical and Microbial Parameters in Wheat Fields

2016-03-21T12:06:55Z

Title: Effects of Monoculture, Crop Rotation, and Soil Moisture Content on Selected Soil Physicochemical and Microbial Parameters in Wheat Fields Authors: A. Marais, M. Hardy; M. Booyse, A. Botha Abstract: Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.