Soil organic matter in Northern Ethiopia,current level and predicted trend: a study case of two villages in Tigray     

G. Corral‐Nuñez  D. Opazo‐Salazar  G. GebreSamuel  P. Tittonell  A. Gebretsadik  Y. Gebremeskel  G. Tesfay  C. L. van Beek 《Soil Use and Management》2014,30(4):487-495

Soil degradation resulting from permanent and high pressure on natural resources is a threat for the present and future of agricultural production in Ethiopia. Mono‐cropping, cultivation on steep slopes, use of cattle manure and crop residues as an energy source for cooking are common practices that have led to declining soil organic matter (SOM) contents. The objective of this research was to evaluate the current status of SOM in farmlands and exclosures (areas protected from grazing to allow their natural restoration) in Northern Ethiopia and to explore the long‐term effects of current agricultural practices and an improved scenario on SOM. At present, the SOM content of farmland soils is small, ranging from 2.1% to 2.9%, while exclosures showed a significant recovery after 20 yr of protection, with SOM contents ranging from 2.6% to 5.6%. However, the level of SOM in farmland soils is envisaged to decline given current agricultural practices, that is removal of crop residues and use of manure as an energy source for cooking. We found that applying manure alone appeared to be insufficient to revert this trend, due to limited availability and its alternative uses. Therefore, a multidisciplinary approach including improved manure and compost management needs to be supplemented with energy saving techniques, as fuel use is currently the largest competing claim for organic matter in the area.  相似文献   

Replacing commercial concentrate by Ficus thonningii improved productivity of goats in Ethiopia     

Mulubrhan Balehegn  Lars Olav Eik  Yayneshet Tesfay 《Tropical animal health and production》2014,46(5):889-894

Ficus thonningii (FT) is an important multipurpose fodder tree providing economic and ecological benefits across arid and semi-arid areas in Africa. Despite its availability in many Sub-Saharan African countries, there is lack of information on its effect on animal productivity. Twenty-four male weaned highland goats of age 7?±?1.5 months were randomly assigned to four dietary treatments in a completely randomized block design. All animals were fed wheat straw, water, and salt licks ad libitum. The control group (T1) was fed concentrate mixture at 2 % of their body weight, while in T2, T3, and T4, 25, 50, and 75 % of the weight of concentrate (DM basis), respectively, was replaced by sun dried FT leaf meal. FT leaf meal had acceptable levels crude protein (CP), neutral detergent fiber (NDF), and tannins and has resulted in increased body weight in all treatments. Goats fed T3 diet showed significantly higher (P?<?0.05) values in terms of feed intake, body weight gain, some carcass attributes, and local meat quality indicators than the rest of the treatments. An increase in proportion of FT leaf meal beyond 50 %, however, resulted in decreased body weight gain, and other carcass parameters, despite increased feed intake. Therefore, F. thonningii can be used to replace commercial concentrate mixture up to 50 % to improve feed intake and productivity of Ethiopian highland goats.  相似文献   

Soil respiration characteristics of tropical soils from agricultural and forestry land-uses at Wondo Genet (Ethiopia) in response to C, N and P amendments     

Tesfay Teklay  Anders Nordgren 《Soil biology & biochemistry》2006,38(1):125-133

In most parts of tropical Africa, conversion of forests into agricultural lands is often accompanied by drastic changes in soil properties. However, little study has been done to examine changes in biological properties of soils from different land-uses in response to addition of C and nutrients. We conducted this study with the aim of investigating nutrient limitations for microbial activity in soils from agricultural (farm) and forest land-uses at Wondo Genet (Ethiopia) after amendment with C and limiting nutrients. We measured CO₂ respiration rates from the soils incubated in the laboratory before and after addition of glucose-C together with N and/or P in excess and/or limiting amounts. Based on the respiration kinetics, we determined the basal respiration (BR), substrate-induced respiration (SIR), specific-microbial growth rate (μ), respiration maxima (R_max), % of glucose-C respired, and microbially available N and P in the soils. We found that N was more limiting than P for the micro-biota in the soils considered, suggesting the presence of ample amounts of indigenous P that could be extracted by the micro-biota, if provided with C. Addition of P resulted in a respiration pattern with two peaks, presumably reflecting different N pools being available over time. The SIR, Respiration maxima, μ and microbially available P were higher in soils from the farm, while %C respired was higher in the forest, suggesting increased C costs for micro-biota to be able to utilize nutrients that are strongly bound to organic-matter or clay minerals. Depending on land-use, about 49-69% of added glucose-C was respired during two and a half weeks time, but differences between N or P additions were not significant. The correlation between soil physical and chemical properties and respiration parameters, however, depended on whether N or P was limiting. We concluded that examining the soil respiration kinetics could provide vital information on nutritional status of micro-organisms under different land-uses and on potential availability of nutrients to plants.  相似文献   

Crop coefficient, yield response to water stress and water productivity of teff (Eragrostis tef (Zucc.)     

A. Araya  Leo StroosnijderG. Girmay  S.D. Keesstra 《Agricultural Water Management》2011,98(5):775-783

In the semi-arid region of Tigray, Northen Ethiopia a two season experiment was conducted to measure evapotranspiration, estimate yield response to water stress and derive the crop coefficient of teff using the single crop coefficient approach with simple, locally made lysimeters and field plots. During the experiment we also estimated the water productivity of teff taking into account long-term rainfall probability scenarios and different levels of farmers’ skills. During the experimental seasons (2008 and 2009), the average potential evapotranspiration of teff ranged from 260 to 317 mm. The total seasonal water requirement of teff was found to lower in contrast to the assumptions of regional agronomists that teff water requirement is comparable to that of wheat and barley (375 mm). The average single crop coefficient values (k_c) for the initial, mid and late season stages of teff were 0.8-1, 0.95-1.1 and 0.4-0.5, respectively. The seasonal yield response to water stress was 1.04, which indicates that teff exhibits a moderately sensitive and linear response to water stress. The results suggest that teff is likely to give significantly higher grain yield when a nearly optimal water supply is provided. The study showed that, in locations where standard equipment is not affordably available, indicative (rough) crop evapotranspiration values can be obtained by using field plots and employing locally made lysimeters. The difference in economic water productivity (EWP) and the crop water productivity (CWP) for teff were assessed under very wet, wet, normal, dry and very dry scenarios. In addition two groups of farmers were evaluated, a moderately (I) and a highly skilled (II) group. The results showed that higher EWP and CWP were obtained under very wet scenario than very dry scenario. There was also a 22% increase in EWP and CWP under group II compared to group I farmers. The increase was due to a 22% reduction in unwanted water losses achieved through use of improved technology and better irrigation skills. Both EWP and CWP can be used to evaluate the pond irrigation water productivity (IWP) for a given climate, crop and soil type, and skill and technology level of the farmer. For special crops like teff extra criteria may be needed in order to properly evaluate the pond irrigation water productivity. During the experimental seasons, a high IWP for teff was attained when about 90% of the optimal water need of the crop was met. IWP can be used as an indicator as how much supplementary irrigation has to be applied in relation to the rainfall and other sources of water supply in order to assure greatest yield from a total area. However, the supplemental irrigation requirement of the crops may vary with season due to seasonal rainfall variability.  相似文献   

Assessing drought risk and irrigation need in northern Ethiopia     

A. Araya  Leo Stroosnijder 《Agricultural and Forest Meteorology》2011,151(4):425-436

Long-term climate data of four stations in the northern Ethiopia were analyzed in combination with information from local farmers and documented materials. From this analysis, a suitable drought-assessing technique was developed and site-specific needs for supplementary irrigation were explored. Results showed that our technique for assessing drought and crop failure corresponded well with farmer observations. The three major causes of crop failure (dry spells, short growing period and “total lack of rain”) which were explicitly listed and ranked by the local farmers were found to match the analyzed data well. The agro-meteorological variables with the most severe consequences were “short growing period” and “total lack of rain”. To prolong the growing period, supplementary irrigation is recommended in the month of September for three of the stations (Maychew, Mekelle and Adigudom) because: (1) rain frequently stops in early September or late August and crops have no other source of water for the rest of the growing period; (2) sufficient surface runoff can be harvested in July and August to be stored in farm ponds and used in September; (3) more cultivable land can be irrigated if supplementary irrigation is scheduled only for the month of September; and (4) giving supplementary irrigation in September can cut yield reduction by over 80% and crop failure by over 50%, except at Alamata. At Alamata, supplementary irrigation must be scheduled for July. The conditions experienced during the famine years of the early 1980s were primarily caused by the continued total rain failure over multiple years. Giving supplementary irrigation in July or September would probably not have mitigated the effects of these droughts, especially at Alamata and Maychew stations.  相似文献   

Partial replacement of dried Leucaena leucocephala (Lam.) de Wit leaves for noug (Guizotia abyssinica) (L.f.) Cass. seed cake in the diet of highland sheep fed on wheat straw     

Temesgen Tesfay  Yayneshet Tesfay 《Tropical animal health and production》2013,45(2):379-385

This study investigated the effect of replacing noug (Guizotia abyssinica) (L.f.) Cass. seed cake by dried Leucaena leucocephala (Lam.) de Wit leaves on feed intake, live weight gain, nutrient digestibility, and nitrogen balance of highland sheep in Tigray Region in northern Ethiopia. Twenty intact yearling male highland sheep weighing16.9?±?1.62 kg were used in a randomized complete block design and included the following four treatments: T1 (control, wheat straw ad libitum?+?200 g noug seed cake (NSC)?+?150 g wheat bran (WB)); T2 (wheat straw ad libitum?+?170 g NSC?+?44.3 g dried L. leucocephala (DLL)?+?150 g WB); T3 (wheat straw ad libitum?+?140 g NSC?+?87.3 g DLL?+?150 g WB); and T4 (wheat straw ad libitum?+?110 g NSC?+?130.2 g DLL?+?150 g WB). Sheep fed on T4 diet consumed higher total dry matter (658 g/head/day) and recorded the highest average daily weight gain (59 g/head/day). Sheep fed on T4 diet had higher dry matter (61 %), organic matter (63 %), and crude protein (75 %) digestibility values than the other treatments. Sheep fed on T3 diet demonstrated higher feed conversion ratio (11.93) than sheep kept on the other treatments. All sheep exhibited positive nitrogen balance, with the highest nitrogen retention being measured in T4 (12 g/head/day). It is concluded that partially replacing NSC by DLL can improve total dry matter intake, digestibility of nutrients, and body weight gain in highland sheep fed on wheat straw as the basal diet.  相似文献   

Effects of fixed time AI and AI at detected estrus on conception rate in smallholder zebu and crossbred heifers and cows subjected to double PGF2α administration     

Tadesse Gugssa  Gebregiorgis Ashebir  Tesfay Yayneshet 《Tropical animal health and production》2016,48(6):1209-1213

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Detection of reaginic antibodies against Faenia rectivirgula from the serum of horses affected with Recurrent Airway Obstruction by an in vitro bioassay     

Gabriel Morán  Hugo Folch  Oscar Araya  Rafael Burgos  Miguel Barria 《Veterinary research communications》2010,34(8):719-726

Reaginic antibodies, mainly of the IgE and some IgG subclasses, play an important role in the induction of type I immediate hypersensitivity reactions. These antibodies bind through their Fc fragment to high affinity receptors (FcεRI) present in the membrane of mast cells and basophils. Previously, several studies have investigated the role of reaginic antibodies in the pathogenesis of RAO. However, whereas immunological aspects of RAO have been extensively studied, the precise sequence of events is still not well understood and role of IgE in this disease still remains controversial. Therefore, in this study a bioassay was developed for reaginic antibody determination in serum from RAO-affected horses in order to determine the etiology of disease. The technique involves measuring in vitro calcium mobilization in RBL-2H3 cells following incubation with horse serum from RAO-affected or unaffected horses and one of the RAO antigens (Faenia rectivirgula). Results demonstrated that 15% of samples from the RAO-affected horses reacted positively in this in vitro bioassay, whereas the samples from unaffected horses did not. This bioassay indicates that reaginic antibodies could be involved in the immunological mechanism leading to RAO; and this technique may facilitate future research in other allergic diseases in horses.  相似文献   

Effects of Bicarbonate,Xanthan Gum,and Preparation Methods on Biochemical,Physicochemical, and Gel Properties of Nile Tilapia (Oreochomis niloticus Linn) Mince     

Geerada Kaewjumpol  Araya Ahromrit  Thanakorn Rojanakorn 《Journal Of Aquatic Food Product Technology》2013,22(3):241-257

This study was aimed to determine the effects of phosphate compound substitutions (sodium bicarbonate and xanthan gum) and preparation methods—headed, gutted whole fish, and mince; fresh and after frozen storage (?20°C for 3 months)—on Nile tilapia mince qualities. Results showed that bicarbonate (0.3% with 8% sucrose/sorbitol) is an efficient phosphate compound replacement as evidenced by the comparative values of salt extractable protein, Ca²⁺-ATPase activity, total sulfhydryl content, and textural properties to those of the phosphate-added—0.3% sodium tripolyphosphate (STPP) with 8% sucrose-sorbitol—sample after 3-month frozen storage (p > 0.05). Both cryoprotected samples containing STPP or bicarbonate exhibited higher denaturation temperatures of myosin than others. Xanthan gum (0.5%) could neither stabilize the biochemical and physicochemical properties of mince during 3-month frozen storage nor improve textural properties of gel from frozen whole fish.  相似文献   

Growth,survival and enzyme activity of lions‐paw scallop (Nodipecten subnodosus) spat treated with probiotics at the hatchery     

Andrs Granados‐Amores  ngel I Campa‐Crdova  Rubn Araya  Jos M Mazn‐Sustegui  Pedro E Saucedo 《Aquaculture Research》2012,43(9):1335-1343

Different types and concentrations of probiotics were evaluated for their effects on growth, survival and enzyme activity of hatchery‐reared Nodipecten subnodosus spat. The treatments included (1) a mix of the microalgae Isochrysis galbana and Pavlova salina as the control group; (2) Diet 1 + a mix of Burkholderia cepacia and Pseudomonas aeruginosa; (3) Diet 1 + the commercial probiotic Epicin; and (4) Diet 1 + the commercial probiotic Bactosafe. Both commercial probiotics were tested at 3, 6 and 10 mg L⁻¹. Scallops receiving Bactosafe and Epicin at 3 and 6 mg L⁻¹ grew ~30% faster and larger than in the control group. Regardless of the treatment, survival at the end was 98.7%. There was no relation between the activity of catalase and superoxide dismutase; however, significantly lower catalase levels occurred at increasing doses of Epicin; significant higher catalase levels occurred in the control group and mix of bacilli. Compared with the control group, lysozyme levels were significantly higher with the Epicin and Bactosafe treatments (3 and 6 mg L⁻¹). More research needs to be conducted with probiotics to determine their real effects on the activity of antioxidant enzymes. We expect that treated scallops will increase their performance at the field.  相似文献