Environmental degradation resulting from current climate changes, including prolonged drought, land degradation, desertification, and loss of biodiversity, is presenting enormous challenges to achieve food security an...Environmental degradation resulting from current climate changes, including prolonged drought, land degradation, desertification, and loss of biodiversity, is presenting enormous challenges to achieve food security and eradication of poverty in the marginal regions （about 90% of the total area） of Egypt. In addition to the natural constraints of high temperature, wind erosion, sand dune movement, and recurrent drought, such regions are subjected to improper land and water management. Moreover, there is a lack of knowledge, technologies, and experiences to match with the current severe climatic changes. There is a great need for establishing sustainable integrated ecosystem rehabilitation and management programs to overcome such problems in the marginal areas, particularly in the Sinai Peninsula due to its strategic and social importance. A series of research and development programs have been conducted in 2006 to im- prove the livelihoods of smallholders through enhancing the efficient management and utilization of local resources that can cope with the drastic changes of climate in the Sinai Peninsula. An integrated livestock/salt-tolerant fodder crop system was introduced, in 2010 by the project teamwork of Desert Research center, Egypt, to many smallholders in the South Sinai region, where studies were conducted at both the general research and individual farmer levels. The most important results were： （1） adoption of the most salt-tolerant genotypes of three forage crops： pearl millet （Pennisetum glaucum L.）, sorghum （Sorghum bicolor）, and Sudan grass （Sorghum sudanense （Piper） Stapf.）; two cereal crops （triticale and barley）; and two oil crops： safflower （Carthamus tinctorius） and Brassica （Mustard）. Alfalfa （Medicago sativa L. and Medicago arborium）, cowpeas （Vigna sinensis L.）, fodder beets （Beta vulgaris L.）, clumping desert bunchgrass （Panicum turgedum）, ryegrass （Lolium perenne） Ray grass, forage shrubs （Kochia indica, Atriplex num- mularia, Sesbania sesban L.）, and Acacia cyanophila, Leucaena leucocephala, Porsopis cheilanses, and Prosopis jioflora were also evaluated; （2） active participation of farmers in development of management strategies to improve ir- rigation water use efficiency, forage production, and livestock production; and （3） economic evaluation at the farmer level, which showed that feeding livestock salt-tolerant fodders produced an increase of about 60% in milk production and 80% in meat production, and reduced feed costs by about 40%. Accordingly, a 70% increase of family income was achieved. It is concluded that better utilization of fragile ecosystem resources and growing salt-tolerant fodder crops may contribute to the development of marginal areas and enhance the living standards of local people through providing high-quality livestock feed materials and producing economical animal products.展开更多
针对饲料油菜机械化收获中的切碎、抛送等关键环节离散元仿真缺乏准确模型的问题,以抽薹期饲料油菜茎秆为研究对象,利用EDEM仿真软件开展饲料油菜茎秆破碎离散元仿真模型参数标定研究。试验测定了饲料油菜本征参数,应用HertzMindlin基...针对饲料油菜机械化收获中的切碎、抛送等关键环节离散元仿真缺乏准确模型的问题,以抽薹期饲料油菜茎秆为研究对象,利用EDEM仿真软件开展饲料油菜茎秆破碎离散元仿真模型参数标定研究。试验测定了饲料油菜本征参数,应用HertzMindlin基本模型进行饲料油菜茎秆颗粒堆积仿真试验,通过二水平因子试验、最陡爬坡试验和响应曲面试验,确定了饲料油菜茎秆颗粒碰撞恢复系数、静摩擦因数和滚动摩擦因数等基本接触参数。在此基础上,应用HertzMindlin with bonding接触模型进行饲料油菜茎秆弯曲破坏仿真试验,通过响应面分析确定了饲料油菜茎秆颗粒法向接触刚度、切向接触刚度、临界法向应力与临界切向应力等饲料油菜茎秆破碎离散元仿真模型的主要参数。以确定的参数进行堆积角仿真试验,结果表明,仿真结果与实测值相对误差为2.27%;不同直径油菜茎秆破碎仿真试验表明,仿真结果与实测值相对误差不大于4.21%,说明标定方法正确可行,标定参数准确可靠。展开更多
基金the International Centre for Biosaline Agriculture (ICBA)the Islamic Development Bank (IDB)+1 种基金the OPEC Fund for International Development (OFID)the International Fund for Agricultural Development (IFAD) for their financial support to enable the project team work of the Desert Research Center (DRC) to conduct this project
文摘Environmental degradation resulting from current climate changes, including prolonged drought, land degradation, desertification, and loss of biodiversity, is presenting enormous challenges to achieve food security and eradication of poverty in the marginal regions （about 90% of the total area） of Egypt. In addition to the natural constraints of high temperature, wind erosion, sand dune movement, and recurrent drought, such regions are subjected to improper land and water management. Moreover, there is a lack of knowledge, technologies, and experiences to match with the current severe climatic changes. There is a great need for establishing sustainable integrated ecosystem rehabilitation and management programs to overcome such problems in the marginal areas, particularly in the Sinai Peninsula due to its strategic and social importance. A series of research and development programs have been conducted in 2006 to im- prove the livelihoods of smallholders through enhancing the efficient management and utilization of local resources that can cope with the drastic changes of climate in the Sinai Peninsula. An integrated livestock/salt-tolerant fodder crop system was introduced, in 2010 by the project teamwork of Desert Research center, Egypt, to many smallholders in the South Sinai region, where studies were conducted at both the general research and individual farmer levels. The most important results were： （1） adoption of the most salt-tolerant genotypes of three forage crops： pearl millet （Pennisetum glaucum L.）, sorghum （Sorghum bicolor）, and Sudan grass （Sorghum sudanense （Piper） Stapf.）; two cereal crops （triticale and barley）; and two oil crops： safflower （Carthamus tinctorius） and Brassica （Mustard）. Alfalfa （Medicago sativa L. and Medicago arborium）, cowpeas （Vigna sinensis L.）, fodder beets （Beta vulgaris L.）, clumping desert bunchgrass （Panicum turgedum）, ryegrass （Lolium perenne） Ray grass, forage shrubs （Kochia indica, Atriplex num- mularia, Sesbania sesban L.）, and Acacia cyanophila, Leucaena leucocephala, Porsopis cheilanses, and Prosopis jioflora were also evaluated; （2） active participation of farmers in development of management strategies to improve ir- rigation water use efficiency, forage production, and livestock production; and （3） economic evaluation at the farmer level, which showed that feeding livestock salt-tolerant fodders produced an increase of about 60% in milk production and 80% in meat production, and reduced feed costs by about 40%. Accordingly, a 70% increase of family income was achieved. It is concluded that better utilization of fragile ecosystem resources and growing salt-tolerant fodder crops may contribute to the development of marginal areas and enhance the living standards of local people through providing high-quality livestock feed materials and producing economical animal products.
文摘针对饲料油菜机械化收获中的切碎、抛送等关键环节离散元仿真缺乏准确模型的问题,以抽薹期饲料油菜茎秆为研究对象,利用EDEM仿真软件开展饲料油菜茎秆破碎离散元仿真模型参数标定研究。试验测定了饲料油菜本征参数,应用HertzMindlin基本模型进行饲料油菜茎秆颗粒堆积仿真试验,通过二水平因子试验、最陡爬坡试验和响应曲面试验,确定了饲料油菜茎秆颗粒碰撞恢复系数、静摩擦因数和滚动摩擦因数等基本接触参数。在此基础上,应用HertzMindlin with bonding接触模型进行饲料油菜茎秆弯曲破坏仿真试验,通过响应面分析确定了饲料油菜茎秆颗粒法向接触刚度、切向接触刚度、临界法向应力与临界切向应力等饲料油菜茎秆破碎离散元仿真模型的主要参数。以确定的参数进行堆积角仿真试验,结果表明,仿真结果与实测值相对误差为2.27%;不同直径油菜茎秆破碎仿真试验表明,仿真结果与实测值相对误差不大于4.21%,说明标定方法正确可行,标定参数准确可靠。
