Biological pest management by predators and parasitoids in the greenhouse vegetables in China

China has the highest greenhouse-based production in the world. In 2010, the area of greenhouses devoted to vegetable production was estimated at 4.7 million ha. With the increasing costs of pest control, expanding pesticide resistance and the growing consumer concern regarding pesticide residues in fresh vegetables, a strong demand for applying non-chemical control methods is emerging in China. Biological control in the greenhouse environment is a viable alternative to pesticide use from both environmental and economic perspectives. Although we have only 17 cases of fully documented, successful biological control operations from China, involving 8 crops, 8 pest species and 14 species of natural enemies, the use of the biological control agents is much more widespread. There are 7 commercial companies and facilities producing 21 species of natural enemies, and most of them are available country-wide. Several of these employ a rearing system using artificial diets, and many now move to an integrated production system, including the mass production of the biocontrol agents, quality control, methods of long-distance transportation, release recommendations, and user feedback. While initially these systems relied on introduced natural enemies, they increasingly develop modified systems using native natural enemies. The increasing demand for pesticide-free, high quality vegetable produce year-round and the existing certification schemes make it very likely that the use of biocontrol agents will continue to increase in China.     

Carbon and Water Footprints and Energy Use of Greenhouse Tomato Production in Northern Italy

This study reports on the carbon, water, and energy footprints of tomatoes grown in a greenhouse in Northern Italy and two possible future variations of heating and carbon dioxide (CO₂) fertilization on the current setup. The heat supply in place, consisting of natural gas (NG) and canola oil combustion, is compared to cogeneration and incineration of municipal solid waste for heating and CO₂ from industrial exhaust for fertilization. As a benchmark, the current system is also compared to a conventional system, in which heat is delivered solely based on NG. Each kilogram (kg) of fresh tomatoes (“Cuore di Bue” variety) produced in the current greenhouse emits 2.28 kg CO₂ equivalents (eq) and uses 95.5 megajoules (MJ) eq energy and 122 liters (L) of water. Relative to the system in place, the carbon footprint (CF) is 57.5% and 18% higher with conventional NG heating and cogeneration and is 40% lower with waste valorization. Further, 33%, 55%, and 63% less energy and 9%, 96%, and 14% less water are used in the conventional, cogeneration, and waste valorization scenarios, respectively. This confirms that there are multiple strategies to reduce the impact of the tomato production under consideration.     

广西生态农业:历程、成效、问题及对策

生态农业已成为世界农业发展的重要模式和方向。广西生态农业的发展具有基础好、起步早、发展快、模式多、效益佳的特点。从新中国成立至今,广西生态农业经历了4个发展阶段:第一阶段(1949—1977年):群众自发,实践摸索;第二阶段(1978—1991年):模式创新,高产高效;第三阶段(1992—2002年):政府推动,全面推广;第四阶段(2003年至今):模式优化,提质增效。60多年来,广西生态农业发展取得了显著的经济效益、生态效益和社会效益,具体表现在:增加产量、提高效益、改善品质、节约资源、保护环境、提升人员素质、扩大国内外影响等7个方面。当前,广西生态农业存在着6个方面的突出问题:(1)科技薄弱,人才不足;(2)经济落后,资金缺乏;(3)生态脆弱,条件恶劣;(4)技术组装不配套,理论研究不深入;(5)意识不强,措施不力;(6)规模化不够,产业化不强。为使广西生态农业今后又好又快地发展,必须采取如下对策和措施:一是提高认识,转变观念;二是搞好规划,完善制度;三是增加投入,改善条件;四是重视科技,培养人才;五是调整结构,优化模式;六是因地制宜,发挥优势;七是加强交流,开展合作;八是综合配套,全面发展;九是"三效"(经济效益、生态效益和社会效益)并举,良性循环;十是"四化"(规模化、产业化、集约化、科技化)同步,持续发展。     

姜寨遗址先民食谱分析

尽管通过C、N稳定同位素分析已对陕西临潼姜寨遗址先民的食物结构和粟作农业进行了初步探索,但研究中的一些重要问题,如不同时期先民食物结构的演变,姜寨与半坡、史家先民食物结构间的差异等,依然未能深入讨论。为此,本文对姜寨遗址出土的不同时期(一期、二期)人骨进行了C、N稳定同位素分析,试图揭示先民食物结构的演变历程,探索姜寨与半坡、史家先民食物结构间的差异,并初步探讨产生这种差异的可能原因。人骨的δ13C平均值(-9.7±1.0‰)和δ15 N平均值(8.5±0.5‰),表明粟类食物(包括粟类作物以及依赖于粟类作物的动物等)在姜寨先民食谱中占据主要地位,且动物资源在食物中的比例相对较低。两期先民的δ13C和δ15N值,无显著性差异,表明先民一直从事粟作农业以及家畜的饲养活动。食谱分析并未发现第二期先民食用更多野生动物的证据,这可能与先民样品量相对偏少、二期先民食用的野生动物比例上升较小、动物类食物在先民食谱中所占比例较小等原因有关。对比地理位置毗邻、文化年代相近的姜寨、史家、半坡遗址先民δ13C值,姜寨(-9.7±1.0‰,N=19)与史家(-10.0±0.7‰,N=9)接近,而远高于半坡(-14.8±1.9‰,N=5),表明半坡遗址粟作农业的种植规模要逊于姜寨和史家遗址。我们认为,不同遗址间先民δ13C值的差异,可能受半坡样品量偏少、遗址间小生态环境不同等因素的影响。     

拜泉生态农业建设的生态资产响应

利用指标相对评价法,选择7个关键指标,对黑龙江省皋泉县生态农业建设情况的评价得出,该县生态资产从20世纪70年代末仅占系统自然生态资产总量的13.75%上升到目前的25.21%,说明生态农业建设对缓解生态资产的耗竭,提高其积累速度具有重要作用。     

Migration and Agricultural Change: The Case of Smallholder Agriculture in Highland Ecuador

A large and growing number of agricultural households in less developed countries are also engaged in international migration. Thousands of farmers from the highland provinces of Cañar and Azuay, Ecuador, have immigrated to metropolitan New York, where they work in menial jobs and remit, as a group, millions of dollars annually. This paper examines the effects of international migration on agricultural production and land-use in two regions of Cañar Province. An agricultural survey was administered in two communities to determine land-use and agricultural production of migrant and nonmigrant households. Contrary to most reports on the subject, migration has neither led to agricultural abandonment nor have remittances been dedicated to agricultural improvements. Semisubsistence agriculture remains an important riskaverse economic and cultural activity, but cultivation is a poor investment. A large investment in housing and land has converted much of the region into a peri-urban landscape of cultivated real estate.     

Carbon emission and sequestration by agricultural land use: a model study for Europe

A model was developed to calculate carbon fluxes from agricultural soils. The model includes the effects of crop (species, yield and rotation), climate (temperature, rainfall and evapotranspiration) and soil (carbon content and water retention capacity) on the carbon budget of agricultural land. The changes in quality of crop residues and organic material as a result of changes in CO₂ concentration and changed management were not considered in this model. The model was parameterized for several arable crops and grassland. Data from agricultural, meteorological, soil, and land use databases were input to the model, and the model was used to evaluate the effects of different carbon dioxide mitigation measures on soil organic carbon in agricultural areas in Europe. Average carbon fluxes under the business as usual scenario in the 2008–2012 commitment period were estimated at 0.52 tC ha^?1 y^?1 in grassland and ?0.84 tC ha^?1 y^?1 in arable land. Conversion of arable land to grassland yielded a flux of 1.44 tC ha^?1 y^?1. Farm management related activities aiming at carbon sequestration ranged from 0.15 tC ha^?1 y^?1 for the incorporating of straw to 1.50 tC ha^?1 y^?1 for the application of farmyard manure. Reduced tillage yields a positive flux of 0.25 tC ha^?1 y^?1. The indirect effect associated with climate was an order of magnitude lower. A temperature rise of 1 °C resulted in a ?0.05 tC ha^?1 y^?1 change whereas the rising CO₂ concentrations gave a 0.01 tC ha^?1 y^?1 change. Estimates are rendered on a 0.5 × 0.5° grid for the commitment period 2008–2012. The study reveals considerable regional differences in the effectiveness of carbon dioxide abatement measures, resulting from the interaction between crop, soil and climate. Besides, there are substantial differences between the spatial patterns of carbon fluxes that result from different measures.     

Lactic acid production from agriculture residues

Various agriculture feedstock residues were evaluated for lactic acid production by simultaneous saccharification and fermentation (SSF) using Lactobacillus delbrueckii and Lactobacillus plantarum, without any additional nutrients. Lactic acid production was higher in alfalfa fiber and soya fiber compared to corncob (soft) and wheat straw. In Lactobacillus plantarum, the amount of lactic acid obtained from alfalfa fiber and soya fiber was 46 and 44 g/100 g fiber, respectively. However, in Lactobacillus delbrueckii, the lactic acid production in soya fiber was 44 g/100 g fiber and that of alfalfa was 32 g/100 g fiber. Small amounts of acetic acid were also produced from SSF of agricultural feedstocks residues. During SSF of alfalfa fiber, lactic acid production in both L. delbrueckii and L. plantarum was enhanced by adding pectinases and cellulases. Lactic acid production from alfalfa fiber did not change with increasing O₂ transfer rates in the fermentation medium, whereas acetic acid production in both Lactobacillus cultures increased with increasing O₂ transfer rates.     

广东省生态农业建设及其发展对策

介绍了广东生态农业的产生和发展的背景及生态农业建设的基本情况,并着重对目前广东省生态农业建设的9种主要模式及其经济和生态效益以及存在的问题进行了较详细的分析,在此基础上提出了广东生态农业发展的主要对策。