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21.
The development and establishment of agroforestry systems is often suggested as a way to stabilize rural economies in developing countries [King, 1979]. At the same time, some traditional systems are being lost, due to an inability to protect the perennial or tree crop components of the system. These traditional systems and the forces that reinforce or destroy them should be carefully studied by those in the process of encouraging adoption of agroforestry systems in the developing world. The gum gardens of Western Sudan are a case in point.Acacia senegal (hashab) andAcacia seyal (talh) are the two major marketable gum-producing trees found in the western region of Sudan. TheAcacias are grown as part of an agro-silvo-pastoral system that has persisted for more than a hundred years in Kordofan Province, where 70% of Sudan's gum Arabic was once produced, as well as most of its grain and livestock products. After a lengthy drought lasting from 1979 to 1985 gum production in Sudan drastically decreased. It was reported that pest attacks and drought were major causal agents in the decline of gum production [Awouda, 1989; Sungar, 1986]. A survey executed in Northern Kordofan Province, starting in August of 1986, did uncover a great number of deadAcacias due to drought and pest attack, but from interviews with gum farmers we conclude that the decline in gum production is largely due to unfavorable socioeconomic relationships exacerbated by the drought, leading to the deterioration of the agroforestry system of production. An inability to get a fair price for gum at the local level and increasing emphasis on a cash economy led to the neglect of the tree components of the system. The gum gardens have long flourished with the intensive husbandry of small-scale farmers. Once these farmers were no longer able to care for them, the gum trees disappeared from the system, indicating that a lack of community stability can be fatal to even a well-developed agroforestry system.  相似文献   
22.
Rangelands cover about 82% of the arid area of Morocco. It is generally acknowledged that these areas are threatened by desertification. Monitoring desertification requires accurate knowledge about the current status of rangeland degradation. Remote sensing is widely used to assess changes in land cover, but its use in arid rangelands has limitations because of spectral confusion among various types of land cover. The objective of this study was to assess the severity and spatial extent of rangeland degradation in the high plateaus of eastern Morocco, using a knowledge‐based approach combining remote sensing and ancillary data. This approach relies on analyzing datasets derived from Landsat TM satellite imagery, lithology, bioclimatic data and field measurements. The level of rangeland degradation was assessed using indicators such as vegetation parameters, grazing levels and cultivation intensity, which provided a high level of accuracy for mapping and monitoring the degradation of the arid rangelands. The results showed that the total area of degraded rangeland in the high plateaus of eastern Morocco is about 17,417 km2, accounting for 48% in the studied area. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
23.
Tomato pomace, delignified by the edible oyster mushroom, Pleurotus ostreatus, could be used as a poultry feed ingredient to provide alpha-tocopherol for retardation of lipid oxidation in postmortem meat if the antioxidant were retained in pomace after fungal fermentation. Experiments were conducted to investigate changes in the content of alpha-tocopherol, lycopene, and beta-carotene in tomato pomace after sterilization and treatment with P. ostreatus from 0 to 104 days. alpha-Tocopherol (39.26 to 31.15 microg/g) and lycopene (17.42 to 11.19 microg/g) significantly decreased during sterilization while beta-carotene (42.56 to 35.44 microg/g) did not. The content of carotenoids decreased by day 26 as compared to 0 day for the control and for treated samples. alpha-Tocopherol decreased during fungal fermentation at day 26 as compared to 0 day for the control and increased during the same period for treated samples. By 104 days, only alpha-tocopherol in control pomace was present in a significant amount. The alpha-tocopherol content of mushroom fruit grown in pomace (74.10 microg/g) and in wheat straw (51.36 microg/g) was not significantly different. Tomato pomace could be used as a substrate to successfully grow edible mushrooms; however, the initial level of selected antioxidants and their reduction during fungal fermentation must be considered when delignified pomace is utilized for selected nutrient content in animal feed or products for human consumption.  相似文献   
24.
In order to study the effect of plant growth promoting rhizobacteria (PGPR), Azolla compost and Azolla biochar on some soil quality indicators and rosemary growth, a greenhouse experiment was conducted in a completely randomized design with six replications. Treatments consisted of T1 (control), T2 (1% Azolla compost), T3 (1% Azolla biochar), T4 (PGPR (P. fluorescens), T5 (1% compost + PGPR) and T6 (1% biochar + PGPR). Rosemary growth parameters and nutrients concentration increased in all treatments compared to control. Treatments increased soil nutrient concentrations, soil microbial respiration (SMR) and microbial biomass C (MBC) but decreased soil metabolic quotient (qCO2) compared to control treatment. A significant enhancement in rosemary growth occurred due to the improved soil quality as a result of organic fertilizers application, particularly by co-application of P. fluorescens and compost or biochar of Azolla.  相似文献   
25.
秸秆生物炭对潮土作物产量和土壤性状的影响   总被引:14,自引:0,他引:14  
将秸秆转化为高碳含量和稳定性的生物炭施入土壤无疑可提升碳库,但也会影响土壤性状和作物生长。为评估秸秆生物炭在北方潮土(p H 8.30)的应用潜力,设每季生物炭施用量为0(对照)、2.25(低量)、6.75(中量)和11.3 t hm-2(高量)(四季后总施炭量分别为0、9、27、45.2 t hm-2)4个处理,通过2年小麦-玉米轮作小区试验,观测了作物产量、籽粒品质、氮素吸收和土壤矿质氮、p H、容重、水分的变化。结果显示,中量生物炭处理下第四季玉米产量增加8.43%;中、高量生物炭处理下四季作物总产量提高4.54%~4.92%。生物炭对小麦和玉米籽粒蛋白质、小麦湿面筋含量及容重无负面影响。作物地上部分氮素吸收、土壤矿质氮含量和p H各处理间无明显变化。中、高量处理下四季作物后土壤容重降低2.99%~10.4%,含水量增加10.3%~20.2%,最大持水量提高14.5%~15.0%。表明中、高量秸秆生物炭每季还田对作物有小幅增产作用,且不影响籽粒品质。土壤容重、水分、持水量等物理性状的改善可能是作物增产的重要原因。  相似文献   
26.
A laboratory study was conducted in order to explain successive extractions of reserved potassium by using concentrated HCI under reflux for 13 surface and sub-surface soil samples representing three chosen pedons of soil series (472 ECC Bashika, 463 EKC Rabeaa and 461 ECC Talafar) locations of Nineveh Province in Northern of Iraq. The aim is to investigate role of clay minerals on release of reserved potassium from soils. Results showed that dominated clay minerals were (smectite 〉 illite 〉 kaolinite 〉 chlorite) for both 472 ECC and 461 ECC soil series and were (illite 〉 smectite 〉 kaolinite 〉 chlorite) for 463 EKC soil series. Also results appeared that exchangeable K+ released values were 2,483-4,575 mg/kg at 461 ECC and 463 EKC soil series, respectively; non-exchangeable phase ranged from 752-1,390 mg/kg at 461 ECC and 472 ECC soil series, respectively. Soil fertility was evaluated according to its K+ mica release referring for high K+ release content with range between 3,324-5,516 mg/kg at 461 ECC and 463 EKC soil series, but rate ofK~ released was very law according to parabolic diffusion me,del with range from 195-359 mg/kg at latter soil series respectively. Results reflect effect of clay minerals on potassium release as amount and rates in arid and semi-arid regions. It can be concluded the study soils have a high amount of potassium content with low rate release of it, in turn these soil need particular management.  相似文献   
27.
Companion animals closely share their domestic environment with people and have the potential to, act as sources of zoonotic diseases. They also have the potential to be sentinels of infectious and noninfectious, diseases. With the exception of rabies, there has been minimal ongoing surveillance of, companion animals in Canada. We developed customized data extraction software, the University of, Calgary Data Extraction Program (UCDEP), to automatically extract and warehouse the electronic, medical records (EMR) from participating private veterinary practices to make them available for, disease surveillance and knowledge creation for evidence-based practice. It was not possible to build, generic data extraction software; the UCDEP required customization to meet the specific software, capabilities of the veterinary practices. The UCDEP, tailored to the participating veterinary practices’, management software, was capable of extracting data from the EMR with greater than 99%, completeness and accuracy. The experiences of the people developing and using the UCDEP and the, quality of the extracted data were evaluated. The electronic medical record data stored in the data, warehouse may be a valuable resource for surveillance and evidence-based medical research.  相似文献   
28.
High prevalences of Cryptosporidium and Giardia were recently found in enteric illness patients in the Qikiqtaaluk region of Nunavut, Canada, with a foodborne, waterborne or animal source of parasites suspected. Clams (Mya truncata) are a commonly consumed, culturally important and nutritious country food in Iqaluit; however, shellfish may concentrate protozoan pathogens from contaminated waters. The goal of this work was to investigate clams as a potential source of Cryptosporidium and Giardia infections in residents in Iqaluit, Nunavut. The objectives were to estimate the prevalence and genetically characterize Cryptosporidium and Giardia in locally harvested clams. Clams (n = 404) were collected from Iqaluit harvesters in September 2016. Haemolymph (n = 328) and digestive gland (n = 390) samples were screened for Cryptosporidium and Giardia via PCR, and amplified products were further processed for sequence analyses for definitive confirmation. Giardia DNA was found in haemolymph from 2 clams, while Cryptosporidium was not detected. The two Giardia sequences were identified as zoonotic Giardia enterica assemblage B. The overall prevalence of Giardia in clams near Iqaluit was low (0.6%) compared with other studies in southern Canada and elsewhere. The presence of Giardia DNA in clams suggests human or animal faecal contamination of coastal habitat around Iqaluit in shellfish harvesting waters. Results from this study are intended to inform public health practice and planning in Inuit Nunangat.  相似文献   
29.
The ability of Fuller's earth to adsorb a basic dye (Astrazone Blue — Basic Blue 69) and an acidic dye (Telon Blue - Acid Blue 25) has been studied. The equilibrium saturation adsorption capacities were 1200 mg dye g?1 Fuller's earth and 220 mg dye g?1 Fuller's earth for Astrazone Blue and Telon Blue, respectively. The kinetics of the adsorption processes were studied in an agitated batch adsorber. The time to reach 90% equilibrium value was achieved in less than 1 h. The variables investigated were agitation, adsorbent mass, initial dye concentration and temperature. A limited number of studies were undertaken using a fired clay but significantly lower saturation capacities were obtained, namely, 7 mg dye g?1 fired clay and 40 mg dye g?1 fired clay for Telon Blue and Astrazone Blue, respectively.  相似文献   
30.
Veterinary Research Communications - Sub-acute ruminal acidosis is a type of metabolic disorder in which affected cattle show a considerable depression of rumen pH. This leads to a dramatic decline...  相似文献   
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