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دانلود رایگان مقاله انگلیسی + خرید ترجمه فارسی
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| عنوان فارسی مقاله: | آگروفارستری و بهبود حاصلخیزی خاک: ایده ای از آمازون |
| عنوان انگلیسی مقاله: | Agroforestry and the Improvement of Soil Fertility: A View from Amazonia |
| مشخصات مقاله انگلیسی (PDF) | |
| سال انتشار مقاله | 2012 |
| تعداد صفحات مقاله انگلیسی | 12 صفحه با فرمت pdf |
| رشته های مرتبط | مهندسی کشاورزی، علوم خاک، مدیریت حاصلخیزی و زیست فناوری خاک، حاصلخیزی خاک و تغذیه گیاه |
| مجله مربوطه | علوم خاک شناسی محیطی و عملی (Applied and Environmental Soil Science) |
| دانشگاه تهیه کننده | موسسه ملی تحقیقات درباره آمازون، مرکز تحقیقات علوم کشاورزی، مانائوس، برزیل |
| نشریه | Hindawi |
| مشخصات و وضعیت ترجمه مقاله (Word) | |
| تعداد صفحات ترجمه مقاله | 17 صفحه با فرمت ورد، به صورت تایپ شده و با فونت 14 – B Nazanin |
| ترجمه اشکال | ترجمه توضیحات زیر اشکال انجام شده و اشکال و نمودارها به صورت عکس در فایل ترجمه درج شده است. |
| فرمول ها و محاسبات | تمامی فرمول ها و محاسبات به صورت عکس در فایل ترجمه درج شده است. |
فهرست مطالب:
چکیده
۱ مقدمه
۲ ایده عمومی در خصوص تاثیر درختان روی حاصلخیزی خاک
۳ درختان و کربن خاک
۴ درختان و تنوع زیستی خاک
۵ درختان در خاک های حاره ای
۶ درختان در کشاورزی امازون
۷ نتیجه گیری
بخشی از ترجمه:
مقاله حاضر به بحث در خصوص اثرات درختان روی حاصلخیزی خاک با تاکید بر سیستم های کشاورزی در آمازون می پردازد. بررسی منابعی خصوص اثرات درختان روی خواص فیزیکی و شیمیایی خاک در مناطق حاره ای،نیمه حاره ای و معتدله انجام شده که شامل اکوسیستم های طبیعی و اکوسیستم های زراعی می شود. کربن خاک در شکل ماده آلی به عنوان شاخص فعالیت بیولوژیک و نیز مشکلات سیاسی نظیر ترسیب کربن و تغییر اقلیم مطرح است. در رابطه با خاک های حاره ای و آمازون، اطلاعات در خصوص اثرات درختان روی خاک در سیستم های زراعی سنتی علاوه بر توسعه راه کارهای جایگزین کشاورزی پایدار تر برای منطقه مورد بحث قرار می گیرد . در نهایت مطالعه موردی در منطقه ساوانا رورامیا شمال برزیل معرفی می شود که توالی زمانی سیستم های آگروفارستری بومی اثرات مبرهن عملیات مدیریتی از جمله اثر درختان روی حاصلخیزی خاک را نشان می دهند. استفاده از گونه های مختلف درختی و دیگر عملیات به کار گرفته شده در سیستم های آگروفارستری می تواند یک راهکار جایگزین برای افزایش باروری خاک و حفظ تولیدات کشاوری با اهمیت کاربردی برای پایداری کشاورزی حاره ای تلقی شود.
۱ مقدمه
بر اساس مطالعه انجام شده توسط مرکز آگروفارستری جهانی ICRAF، ۴۳ درصد اراضی زراعی زمین(بیش از ۱ میلیارد هکتار) دارای پوشش درختی بیش از ۱۰ درصد می باشد. سطح وسیعی از اراضی زراعی یعنی ۱۶۰ ملیون هکتار دارای پوشش درختی بیش از ۵۰ درصد هستند. پتانسیل درختان برای بهبود تغذیه، درامد، مسکن، سلامتی و بهداشت، رفع نیاز های انرژی و پایداری زیست محیطی در چشم انداز های کشاورزی موجب شد تاICRAF حضور درختان را به عنوان ممولفه اصلی کشاورزی همیشه سبز معرفی کنند. در میان طیف وسیعی از مزایای ناشی از درختان، یک عنصر مهم اثر مثبت درختان روی خواص خاک و در نتیجه مزایای آن برای گونه های زراعی می باشد. این مقاله به بررسی دانش فعلی در خصوص رابطه بین درخت و خاک بر اساس تحقیقات سیستم های اگروفارستری علاوه بر مطالعات در محیط های طبیعی و غیر زراعی که اثرات درخت را روی خاک اثبات کرده اند می پردازد.
بخشی از مقاله انگلیسی:
This paper discusses the effects of trees on soil fertility, with a focus on agricultural systems in Amazonia. Relevant literature concerning the effects of trees on soil physical and chemical properties in tropical, subtropical, and temperate regions is reviewed, covering both natural ecosystems and agroecosystems. Soil carbon, in the form of organic matter, is considered as an indicator of biological activity as well as in relation to policy issues such as carbon sequestration and climate change. In the case of tropical soils and Amazonia, information on the effects of trees on soils is discussed in the context of traditional agriculture systems, as well as in regard to the development of more sustainable agricultural alternatives for the region. Lastly, attention is given to a case study in the savanna region of Roraima, northern Brazil, where a chronosequence of indigenous homegarden agroforestry systems showed clear effects of management practices involving trees on soil fertility. The use of diverse tree species and other practices employed in agroforestry systems can represent alternative forms of increasing soil fertility and maintaining agricultural production, with important practical applications for the sustainability of tropical agriculture. 1. Introduction According to a study by the World Agroforestry Centre, ICRAF, 43% of the planet’s agricultural lands (more than a billion hectares) has more than 10% tree cover [1]. A lesser but still significant area of agricultural land, 160 million hectares, has more than 50% tree cover. The potential of trees to bring improvements in nutrition, income, housing, health, energy needs, and environmental sustainability in the agricultural landscape has guided ICRAF’s mission, with the presence of trees being the principal component of an “evergreen agriculture” [2]. Within the array of benefits brought by trees, an important element is the positive effect of trees on soil properties and consequently benefits for crops. This paper explores current knowledge as to this relation between trees and soil, based on agroforestry systems research, as well as studies innon-agricultural or natural environments that demonstrate effects of trees on soil. Although we consider information from various ecosystems and biomes, the focus will be on Amazonia, where the authors have most of their experience. This focus on Amazonia is also due to the strong policy demands for the development of more sustainable agricultural systems in the region, as alternatives to forms of land use that have shown significant and negative impacts on natural resources and ecosystem services, such as deforestation for extensive cattle ranching. In this scenario, agroforestry systems have been indicated as one of the more promising alternatives to achieve a more sustainable agriculture, in greater equilibrium with the environment [3]. The presence of trees in farming systems, although an ancient practice, began to gain institutional attention during the 1970s and 1980s, with the beginning of studies on “agroforestry systems”. One of the principal definitions employed in this context was that proposed by Lundgren and Raintree in 1982: “Agroforestry is a collective name for landuse systems and technologies where woody perennials (trees, shrubs, palms, bamboos, etc.) are deliberately used on the same land-management units as agricultural crops and/or animals, 2 Applied and Environmental Soil Science Figure 1: Agroforestry system with rubber (Hevea brasiliensis), cacao (Theobroma cacao), and ac¸a´ı (Euterpe oleracea) in Tome-ac ´ ¸u, Para, showing the litter layer that is typically found in such ´ multistrata systems. Figure 2: Agroforestry system in initial phase, with black pepper (Piper nigrum) as principal cash crop, interplanted with cupuac¸u (Theobroma grandiflorum) and ac¸a´ı (Euterpe oleracea) for future fruit production, as well as timber trees (mahogany—Swietenia macrophylla and ipe—ˆ Tabebuia sp.) and Brazil nut (Bertholletia excelsa) as long-term products. in some form of spatial arrangement or temporal sequence. In agroforestry systems there are both ecological and economical interactions between the different components” [4] (Figures 1, 2, and 3). While trees in general can provide a number of environmental benefits in both rural and urban landscapes, and play key roles in ecosystem services provided by natural areas, in this paper we will restrict our focus to the effects of trees on soil fertility, in the specific context of agricultural systems. Although the benefits that trees can provide on rural properties such as food security, household income, economic stability, and thermal comfort (shade) are most often associated with their products, such as fruit, timber, or other items, the inclusion of trees in agricultural systems can also optimize nutrient cycling and have positive effects on soil chemical and physical properties. This process is especially important in tropical soils, where a high degree of weathering has created deep, leached soils that are poor in Figure 3: Multistrata agroforestry system in Tome-ac ´ ¸u, Para, with ´ harvest of hogplum (Spondias mombin) grown as the upper canopy over cacao and ac¸a´ı. plant nutrients [5, 6]. Although poor in nutrients, tropical soils are very rich in biodiversity, with higher diversity and biomass of microorganisms than temperate soils, with these being the principal agents mediating the supply of nutrients to the soil by means of the decomposition of organic matter, derived from the vegetation [7–9]. In the humid tropics, the removal of surface litter or organic matter generally results in the depletion of soil fertility in a few years [10, 11]. In agricultural systems practiced by traditional peoples, this limitation is circumvented by using the land for a short period (generally 2- 3 years), after which the cultivated areas are left to fallow with natural regeneration of secondary vegetation. The associated ecological interactions reestablish nutrient cycling and recuperate soil qualities, after which the area can once again be used for agriculture [12, 13]. This is the basis for shifting cultivation in Amazonia, a system that has permitted native populations to manage their natural resources over centuries, with small-scale environmental impacts that do not exceed the support capacity and resilience of ecosystems. However, the present-day situation of population growth and increasing pressure on agricultural lands lead to situations where there is demand for more intensive land use. This most often implies in repeated burning, the cheapest way to prepare land for planting, which can interrupt processes of nutrient cycling and accumulation, leading to loss of soil fertility and consequently slowing the recuperation of natural vegetation during fallow cycles [14]. In light of the present-day situation of Amazonia, where there are now good reasons and policy demands to balance conservation with development, it is necessary to think in terms of agricultural systems that optimize nutrient cycling and permit permanent or semipermanent production, as well as minimize dependence on external inputs and have low environmental impact. The inclusion of diverse tree species is a key element in maintaining the production of organic matter and generating other positive benefits, as well as allowing the diversification of products. However, before we discuss topics specific to tropical soils and Amazonia, Applied and Environmental Soil Science 3 the following sections will review general information about the influence of trees on soil and their role in accumulation of soil carbon stocks. 2. A General View of the Influence of Trees on Soil Fertility One of the pioneer studies to measure the effects of individual trees on soils was that by Zinke [15], who looked at pines growing on dunes in northern California, USA. His study found that under trees, certain soil properties exhibited a pattern of radial symmetry, with changes in pH, nitrogen, cations, and cation exchange capacity varying according to distance from the tree trunk, with a peak in these characteristics at a certain distance. Subsequent studies also demonstrated patterns in the variation of soil characteristics as influenced by trees, such as in tropical savannas [16, 17], deserts [18], and areas of temperate forests [19–23]. In analyzing soil characteristics under individual tree crowns in Kenyan savannas, Belsky et al. [16] found greater levels of mineralizable N, microbial biomass, P, K, and Ca underneath the crowns when compared to open savanna. Burke et al. [17] explain that in dry savannas the strong limitation on water availability permits only punctuated establishment of trees and shrubs but that under crowns cycling occurs in a different form than in open grasslands, with the possibility of soil enrichment in a scale of decades. However, such soil changes can be reverted with the death of the tree or by fires. Belsky et al. [16] also point out the effect of nutrients deposited in dung by birds and large mammals that utilize trees as resting places or roosts. Such patterns form what have been called “islands of fertility” or “resource islands” created by trees or bushes, generally in savannas or desert areas. The microenvironment of these “islands” can also influence the composition of the herb stratum [16, 19], soil density [19, 20], and earthworm activity [20, 23] among other factors, allowing the creation of positive feedbacks that favor plant establishment and productivity [23, 24]. At the same time, these patterns can be important indicators of stability or risk of desertification in such areas [17, 18]. Studies of forests in temperate climates indicate variations in soil that can be related to individual tree species. Besides the expected correlations, such as greater levels of N under legumes [20] or lower pH under species that produce acidifying litter, such as Pinus spp. [20, 23], other interesting interactions show that different species can alter soil in distinct ways, with variations in the increment of soil carbon [20], exchangeable Ca and Mg and per cent base saturation [21, 23]. In a study of 14 tree species in Poland, Reich et al. [23] found varied effects on soil characteristics; however, these effects were significantly related to the level of Ca in litter, independent of the species. Trees producing litter rich in Ca were associated with soils with greater pH, exchangeable Ca, and per cent base saturation, as well as greater rates of forest floor turnover and greater diversity and abundance of earthworms. Dijkstra [22] emphasizes that the rate of mineralization of organic Ca is a fundamental factor in this process, since it determines the immediate availability of this nutrient in the soil and can vary between species. The study of vertical patterns of the distribution of nutrients in soil can indicate other phenomena that are not detected when only the horizontal distribution of nutrients is examined. In an evaluation of more than 20,000 globally distributed soil profiles, the greater part in temperate climates, Jobbagy and Jackson [ ´ 25] found that cycling mediated by plants exerts a marked influence on the vertical distribution of nutrients in the soil, especially in the case of more limiting nutrients such as P and K. Patterns of greater concentration of these nutrients in surface layers (0– 20 cm) were attributed to the fact that since these are more important to plants, they are subject to greater uptake and cycling, being absorbed from deeper layers and returned to the soil surface through litterfall and rain water throughfall. This process of uptake functions in opposition to leaching, which moves nutrients downward and acts more strongly on those nutrients that are in lessdemand by plants. If a nutrient is not limiting, its movement in the soil profile will be more influenced by leaching than by cycling and it will present higher concentrations at greater depth, as occurs with Na, Cl, and Mg [25].
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دانلود رایگان مقاله انگلیسی + خرید ترجمه فارسی
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| عنوان فارسی مقاله: | آگروفارستری و بهبود حاصلخیزی خاک: ایده ای از آمازون |
| عنوان انگلیسی مقاله: | Agroforestry and the Improvement of Soil Fertility: A View from Amazonia |
| برای دانلود رایگان مقاله انگلیسی روی عنوان انگلیسی مقاله کلیک نمایید.برای خرید ترجمه آماده ورد، روی عنوان فارسی مقاله کلیک کنید. | |
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