5,936 research outputs found

    Using longitudinal survival probabilities to test field vigour estimates in sugar maple (Acer saccharum Marsh.)

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    Tree mortality is a major force driving forest dynamics. To foresters, however, tree mortality is often considered a loss in productivity. To reduce tree mortality, silvicultural systems, such as selection cuts, aim at removing trees that are more likely to die. In order to identify trees with higher risks of mortality, field classifications are employed that assess vigour based on external characteristics of trees. We used a novel longitudinal approach for estimating survival probabilities based on ring-width measurements, initially developed by Bigler and Bugmann [Bigler, C., Bugmann, H., 2004. Predicting the time of tree death using dendrochronological data. Ecol. Appl. 14 (3), 902-914], to parameterize a survival probability model for sugar maple (Acer saccharum Marsh.) and to test whether field-assessed tree vigour classes are corroborated by survival probabilities determined from radial growth history. Data from 56 dead and 321 live sugar maples were collected in stands in western Quebec (Canada) that had undergone a selection cut ≈10 years prior to sampling. Our results showed that tree vigour established from external defects and pathological symptoms, using the classification of Boulet [Boulet, B., 2005. D

    Causes of household food insecurity in Koredegaga Peasant Association, Oromiya Zone, Ethiopia

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    The main objective of the study was to examine the determinants of households' food security using a logistic regression procedure. The model was initially fitted with eleven factors, of which six were found to be significant, and all exhibited the expected signs. These include farmland size, ox ownership, fertilizer application, education level of household heads, household size, and per capita production. The result was analyzed further to compute partial effects and to conduct simulation studies on significant determinant factors. Analysis of partial effects revealed that an introduction to fertilizer use and an improvement in the educational levels of household heads lead to relatively greater probability of food security. On the other hand, simulations were conducted on the basis of the base category of farmers, representing food secure households, revealed that both educational levels of household heads and fertilizer application by farmers have relatively high potential to more than double the number of food secure households in the study area following improvements in these factors.Food Security and Poverty,

    COOPERATIVE UPLAND WILDLIFE RESEARCH AND SURVEYS

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    Drivers of farmers’ adoption of hermetic storage bags in Ghana

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    Post-harvest loss is a global challenge due to its serious threat to food security. Hermetic storage bags offer one way to combat the loss of food after harvest. The rate at which farmers adopt hermetic bags largely depends upon their access to information and training about the technology. The adoption of hermetic storage bags in Dormaa, Ghana, was the focus of this quantitative cross-sectional research study. This study sought to describe maize farmers’ perceptions of the hermetic storage bags in Dormaa, Ghana, based on the perceived innovation attributes and to ascertain farmers’ stages of adoption of the hermetic storage bags using Rogers’s (2003) innovation-decision model. A multistage systematic sampling technique was used to survey 217 maize farmers in four communities where maize production was the main economic activity. Data indicated that the largest group of farmers were at the confirmation stage of Rogers’ model. The logistic regression model was used to ascertain the influence of the innovation attributes on adoption. The findings reveal that of the five innovation characteristics, relative advantage, compatibility, and complexity are the key and significant drivers of the adoption of hermetic storage bags, with relative advantage and compatibility increasing the adoption likelihood and complexity reducing it. The study, therefore, recommends that communities lagging behind others in adoption should be targeted for additional training

    Effects of Farmers’ Demographic Factors on the Adoption of Grain Storage Technologies Developed by Nigerian Stored Products Research Institute (NSPRI): A case study of selected villages in Ilorin West LGA of Kwara State.

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    This study was carried out to identify the factors that determine farmers’ adoption of NSPRI grain storage technologies in selected villages of Ilorin West Local Government Area of Kwara State. Data used were collected from a total of 120 respondents who were randomly selected from 6 villages of the Local Government Area. 10% of all the farmers in each of the villages were interviewed. The variables examined in the study are sex, age, marital status, primary occupation, secondary occupation, level of education, number of dependents, years of farming, farm size, years of grain production, means of farm land acquisition and types of grain produced. Descriptive statistics and logistic regression model were used to analyze data. The inferential statistical tool used indicated significant relationship between sex and NSPRI grain storage technologies’ adoption.  Level of education and occupation were also significantly related to adoption of NSPRI grains storage technologies. This study recommends a wholesome dissemination model that will benefit both educated and uneducated farmer and also the involvement of farmers’ group or representatives in participatory approach of technology development, introduction and use. Keywords: Education, farming, occupation, participatory development, logit regression model

    Mortality of Sitophilus granarius (L.) and Rhyzopertha dominica (F.) Adults Exposed to Different Concentrations of Filter Cake in Stored Wheat

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    አህፅሮትየሲልከን ውሁድ ያሊቸው ግዑዝ ብናኞች የተከዘነ እህልን ከጎተራ ነፍሳት ከመከሊከል አንጻር ከኬሚካሎች ይልቅ ሇአካባቢ ተስማሚ ሇጤናም ጉልህ ጉዳት የማያስከትለ አማራጮች እየሆኑ መጥተዋል፡፡ ከዚህ ጋር ተያይዞ አንድ የሲሉከን ውሁድ ያሇው የማጣሪያ ኬክ ብናኝ በጎተራ ነፍሳት ሊይ የሚኖረውን የመቆጣጠር አቅም ሇመፈተሽ በጎተራ ነቀዝ እና በትንሹ እህል ቦርቧሪ ጥንዚዛ ሊይ ጥናት ተደርጓል፡፡ ጥናቱ የተከናወነው 1ኪ.ግ.፣ 0.75ኪ.ግ.፣ 0.5ኪ.ግ.፣ እና 0.25ኪ.ግ. የማጣሪያ ኬክ ብናኝ በአንድ ኩንታል ስንዴ ሊይ በመጨመር ሲሆን የብናኙን ውጤታማነት ሇመቆጣጠር ምንም ብናኝ ያልተደረገበት ስንዴ ከጎን ተጠንቷል፡፡ ጥናቱ ባጠቃሊይ ሇ14ቀናት የተከናወነ ሲሆን ብናኝ ባሇው ስንዴ ውስጥ የገቡ ጉልምስ ነፍሳት የደረሰባቸው የሞት መጠን ተገምግሟል፡፡ በዚህም መሠረት በጎተራ ነቀዞች ሊይ በሶስት ቀናት ብቻ ከ41.3% እስከ 70.0% የጉልምሶች ሞት የተከሰተ ሲሆን ይህ በትንሹ እህል ቦርቧሪ ጥንዚዛ ጉልምሶች ሊይ ከ73.3% እስከ 93.3% ሞት አስከትሏል፡፡ ከ14 ቀናት በኋሊ ሲታይ በጎተራ ነቀዝ ጉልምሶች ሊይ እስከ 98.7% ሞት ያስከተሇ ሲሆን በትንሹ እህል ቦርቧሪ ጥንዚዛ ሊይ ግን እስከ 100% ሞትን አስከትሏል፡፡ ስሇዚህ በዚህ ጥናት ሊይ የተካተቱ የነፍሳት ዝሪያዎችን በማጣሪያ ኬክ ብናኝ ከሞሊጎደል መቆጣጠር እንደሚቻል መመልከት ይቻሊል፡፡AbstractSilica based inert dusts are eco-friendly alternatives to control stored grain insect pests due to environmental and health concerns associated with use of synthetic insecticides. A study was conducted to determine the efficacy of filter cake (a silica-based inert dust) on the granary weevil, Sitophilus granarius (L.) and lesser grain borer, Rhyzopertha dominica (F.) in stored wheat. Filter cake dust of ≤0.4 mm particle size was admixed with 500 g of wheat seed to provide nominal rates of 10000, 7500, 5000, and 2500 ppm (mg/kg), while the control treatment consisted of wheat seeds that were untreated. The bioassays were carried out using a liter-sized plastic jars in completely randomized design with three replications. Experiments were maintained at 23.1±1.7oC and 61.0±4.3% relative humidity. Mortality data were collected at 3, 7, and 14 d after treatment. Results indicated that mean mortality rate at 3 d after treatment ranged from 41.3 to 70.0% in S. granarius and 73.3 to 93.3% in R. dominica. Mean mortality of S. granarius adults at 14 d in filter cake treatments was 84.0 to 98.7%, whereas that of R. dominica was 98.3 to 100%. The present results show that filter cake dusts can be used to control these two species in stored wheat. Filter cake has potential in protection of wheat from S. granarius and R. dominica infestations in storage

    Arboreal forage lichen response to partial cutting of high elevation mountain caribou range in the Quesnel Higland of east-central British Columbia

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    Group selection silvicultural systems have been recommended for managing mountain caribou (Rangifer tarandus caribou) habitat in high elevation Engelmann spruce – subalpine fir forests in east-central British Columbia. We measured the response of arboreal lichen (a key winter forage) to harvesting of 30% of the forested area using three partial cutting treatments, which created small (0.03 ha), medium (0.13 ha), and large (1.0 ha) openings, and a no-harvest treatment. Treatments were replicated on four sites, and monitored over a ten year post-harvest period. The short-term loss of lichen associated with removal of approximately one third of the trees was partially offset by a significant (P=0.01) increase in lichen abundance on trees in the caribou feeding zone (up to 4.5 m) in the three partial cutting treatments relative to trees in the uncut forest. Differences among treatments in the change in lichen composition, as measured by the percentage of Alectoria sarmentosa and Bryoria spp., were marginally significant (P=0.10). The partial cutting treatments showing a greater likelihood of shifting towards more Bryoria spp. than no-harvest treatment (P=0.04). In the year of harvest (1993), larger trees were found to hold more lichen than smaller trees (P=0.04), and live trees supported more lichen than dead trees (P=0.01), but lichen loading was similar among tree species (P=0.51). Tree fall rates were similar among treatments, based on the ten year average (0.6–0.8% of sample trees per year). The results indicate that caribou foraging habitat is maintained in the residual forest when group selection systems that remove only 30% of the trees are applied. Information on the distribution of lichen is useful for developing stand level prescriptions. Providing lichen bearing habitat meets just one of the needs of caribou. A comprehensive approach that considers all factors and their interactions is essential to maintain and recover the threatened mountain caribou
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