The impact of increasing farm size and mechanization on rural income and rice production in Zhejiang province,China   总被引：1，自引：0，他引：1  

M. Marrit Van den Berg  Huib Hengsdijk  Joost Wolf  Martin K. Van Ittersum  Wang Guanghuo  Reimund P. Roetter 《Agricultural Systems》2007

Economic growth in China’s agricultural sector lags behind growth in industry and services, creating an ever widening rural–urban income gap. Development of the non-agricultural sectors offers new opportunities for farmers in China’s more advanced provinces such as Zhejiang. Increased income in the urban sector creates markets for new products, and migrating farmers rent their land to those staying. Until now, the prevailing rice-based systems have been managed mainly using manual labour and animal traction, but the larger farms resulting from migration may facilitate, or even require mechanization. In this study, we use a simulation model of the farm household to analyse the effects of increasing farm size and the transition from rice to vegetable production, while also studying the effects of mechanization.  相似文献   

Using drainage systems for supplementary irrigation     

P. J. T. Van Bakel 《Irrigation and Drainage Systems》1988,2(2):125-137

The use of drainage systems for supplementary irrigation is widespread in The Netherlands. One of the operating policies is to raise the surface water level during the growing season in order to reduce drainage (water conservation) or to create subsurface irrigation. This type of operation is based on practical experience, which can be far from optimal.To obtain better founded operational water management rules a total soil water/surface water model was built. In a case study the effects of using the drainage system in a dual-purpose manner on the arable crop production were simulated with the model. Also, the operational rules for managing this type of dual-purpose drainage systems were derived.The average annual simulated increase in crop transpiration due to water conservation and water supply for subsurface irrigation are 6.0 and 5.4 mm.y^–1, respectively. This is equivalent with 520 × 10³ and 460 × 10³ Dfl.y^–1 for the pilot region (2 Dfl 1 US $). The corresponding investments and operational costs are 600 × 10³ Dfl and 9 × 10³ Dfl.y^–1 for water conservation and 3200 × 10³ Dfl and 128 × 10³ Dfl.y^–1 for subsurface irrigation. Hence, water conservation is economically very profitable, whereas subsurface irrigation is less attractive.Comparing the management according to the model with current practice in a water-board during 1983 and 1986 learned that benefits can increase with some 50 and 500 Dfl per ha per year, respectively.  相似文献   

Water balance estimates of evaporation from ponded rice fields in a semi-arid region   总被引：1，自引：0，他引：1  

T. Talsma  A. Van Der Lelij 《Agricultural Water Management》1976,1(1):89-97

Evaporation from ponded rice grown on fine-textured soils was calculated using a simple water balance equation, and compared with pan evaporation measured at a regional meteorological station. Crop/pan (E_r/E_p) evaporation ratios showed seasonal trends, with values generally exceeding unity during the mid- to late-season ponding period. Mid-summer ratios of E_r/E_p for two experimental fields were not significantly different from those reported in a previous study using a different experimental technique, but were higher on a third. On the average, evaporation over the whole ponding period equalled that from a Class A pan. The assumption that the infiltration or seepage term of the water balance may be neglected for fine-textured soils would seriously overestimate E_r on one of the three experimental sites.  相似文献   

接种沙门氏菌苗可使新生雏鸡和强制换羽母鸡得到免疫保护     

Paul Barrow  Peter Holt  Ulrich Methner  胡宇  丁博文 《国外畜牧学(猪与禽)》2007,27(2):46-48

过去人们常认为,由于刚出壳雏鸡的免疫系统尚未发育成熟,同时肠道内缺乏有益的微生物,因而处于高度的敏感期,此时接种沙门氏菌苗产生的保护作用很有限。然而,最新的研究表明,在这些敏感期接种疫苗,可诱发产生保护作用。  相似文献   

3D upscaling of transpiration from leaf to tree using ground-based LiDAR: Application on a Mediterranean Holm oak (Quercus ilex L.) tree     

Dimitry Van der Zande  Simone Mereu  Nadezhda Nadezhdina  Jan Cermak  Bart Muys  Pol Coppin  Fausto Manes 《Agricultural and Forest Meteorology》2009,149(10):1573-1583

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Nitrous Oxide and Carbon Dioxide Emissions from Vietnamese Soil Amended with Different Compost Types at High Temperature     

Van Ngoc Tuong Hoang 《Communications in Soil Science and Plant Analysis》2018,49(7):848-861

This study aims to determine the effects of compost additions and high temperature on N₂O and CO₂ emissions from a Vietnamese agricultural soil. Soil samples amended with two compost types (commercial compost, SH and chicken compost, CC) at three rates of 1%, 2% and 4% w/w were aerobically incubated at 25°C, 30°C and 35°C for 28 days in the laboratory. N₂O and CO₂ emissions were determined on days 1, 3, 5, 7, 14, 21 and 28. Our results showed that N₂O and CO₂ emissions were significantly affected by temperature, compost additions, and their interactions. Greater N₂O and CO₂ emissions were seen in CC treatments than SH treatments. Higher application rates of CC led to greater N₂O and CO₂ emissions. In SH treatments, higher temperature lowered N₂O emissions but did not affect CO₂ emissions. N₂O and CO₂ emissions were enhanced with CC addition while they showed different responses to increasing temperature.  相似文献   

Implementation of two high through-put techniques in a novel application: detecting point mutations in large EMS mutated plant populations     

Antoine LF Gady  Freddy WK Hermans  Marion HBJ Van de Wal  Eibertus N van Loo  Richard GF Visser  Christian WB Bachem 《Plant methods》2009,5(1):13-14

Background  

The establishment of mutant populations together with the strategies for targeted mutation detection has been applied successfully to a large number of organisms including many species in the plant kingdom. Considerable efforts have been invested into research on tomato as a model for berry-fruit plants. With the progress of the tomato sequencing project, reverse genetics becomes an obvious and achievable goal.  相似文献   

The Pelagos Sanctuary for Mediterranean marine mammals     

Giuseppe Notarbartolo‐di‐Sciara  Tundi Agardy  David Hyrenbach  Tullio Scovazzi  Patrick Van Klaveren 《水产资源保护:海洋与淡水生态系统》2008,18(4):367-391

• 1. In February 2002, France, Italy and Monaco agreed to establish an international sanctuary for Mediterranean marine mammals. The resulting Pelagos Sanctuary encompasses over 87500 km² of the north‐western Mediterranean Sea, extending between south‐eastern France, Monaco, north‐western Italy and northern Sardinia, and surrounding Corsica and the Tuscan Archipelago.
• 2. The Pelagos Sanctuary illustrates how the tenets of Marine Protected Area (MPA) design can be reconciled with the dynamic nature of oceanic systems, because its spatial scale was defined by oceanographic and ecological considerations, specifically the location of the Ligurian permanent frontal system.
• 3. By expanding protective measures beyond national waters, the Pelagos Sanctuary also sets a precedent for the implementation of pelagic protected areas in the high seas. The Pelagos Sanctuary will contribute to the conservation of the Mediterranean Sea at two scales: (i) locally, by protecting important cetacean foraging and breeding grounds in the Ligurian Sea, and by providing ‘umbrella’ protection to other marine predators in this area; and (ii) regionally, by empowering other conservation measures, such as the Specially Protected Areas Protocol of the Barcelona Convention and the wider goals of the Agreement on the Conservation of Cetaceans of the Black and Mediterranean Seas (ACCOBAMS).
• 4. However, because few cetacean species are resident within the Sanctuary, their effective long‐term conservation will require large‐scale management and coordinated monitoring throughout the Mediterranean basin.

Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Medicine management in 12 Norwegian fish farms     

Anne-Grethe T Berg  Kari Grave  & Tor E Horsberg 《Aquaculture Research》2008,39(8):861-868

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Comparative energy and economic analyses of conventional and System of Rice Intensification (SRI) methods of rice production in Thai Nguyen Province,Vietnam     

Tuyet Thi Anh Truong  John Fry  Phu Van Hoang  Hoang Huy Ha 《Paddy and Water Environment》2017,15(4):931-941

The consumption of energy inputs in agricultural production has been increasing rapidly during the past decades. However, given the limitations and costs of non-renewable energy, increasing production while using the least energy possible has become a major concern of most nations. Prompted by this concern, we conducted a face-to-face survey of 90 farming households in Thai Nguyen Province, Vietnam, to find out how energy is being used in agriculture and, specifically, in their rice production. Through analysis of energy input–output balances, combined with economic efficiency analysis, a comparison was made of conventional and SRI methods of rice production. The study found that applying the SRI method can save around 23% of energy inputs, while increasing energy outputs by 11%. Economic benefits per hectare also rise by more than 8 million dong (USD 364) compared to those under the conventional cultivation system. The study also showed conflicts between the energy and economic balances for manual compared with machine ploughing operations. This study contributes to providing an overview of energy consumption in rice cultivation at the household level. Its findings can help stakeholders to assess current policies and make better decisions on the uses of energy in agricultural production. In addition, the comprehensive approach taken here to analysing energy use and efficiency could expand the analysis and comparison of energy uses at sectoral or activity level—still a new field in Vietnam and many other countries.  相似文献