The effect of reduced tillage agriculture on carbon dynamics in silt loam soils

Reduced tillage (RT) agriculture is an effective measure to reduce soil loss from soils susceptible to erosion in the short-term and is claimed to increase the soil organic carbon (SOC) stock. The change in distribution and total SOC stock in the 0–60 cm layer, the stratification of microbial biomass carbon (MB-C) content in the 0–40 cm layer and the carbon (C) mineralization in the upper 0–5 cm layer in silt loam soils in Western Europe with different periods of RT agriculture were evaluated. Ten fields at seven locations, representing the important RT types and maintained for a different number of years, and eight fields under conventional tillage (CT) agriculture with similar soil type and crop rotation were selected. RT agriculture resulted in a higher stratification of SOC in the soil profile than CT agriculture. However, the total SOC stock in the 0–60 cm layer was not changed, even after 20 of years RT agriculture. The MB-C was significantly higher in the 0–10 cm layer under RT agriculture, even after only 5 years, compared to CT agriculture. The higher SOC and MB-C content in the upper 0–5 cm layer of RT fields resulted in a higher C mineralization rate in undisturbed soil in the laboratory. Simulating ploughing by disturbing the soil resulted in inconsistent changes (both lower and higher) of C mineralization rates. A crop rotation with root crops, with heavy soil disturbance every 2 or 3 years at harvest, possibly limited the anticipated positive effect of RT agriculture in our research.     

Cultivating Smartcities

On 9 April 2009, Michelle Obama planted the first seedlings of onion, lettuce, peas and peppers in the 102-square-metre (1,100-square-foot) White House Kitchen Garden. She may have planted the green shoots for a smartcity. CJ Lim , author of Smartcities + Eco-warriors (Routledge, 2010), describes sustainable urban developments in the form of smartcities – a new urban exuberance reintegrating cultivated land within an urban economic and ecological context system. These verdant edible edifices of urban spatial theatre are aesthetically and culturally engaging. Soliciting an emotional as well as intellectual response they have the potential to connect with the public and involve them in the architectural possibilities of the city. Copyright © 2010 John Wiley & Sons, Ltd.     

农作物中抗生素检测技术的研究进展

随着养殖业的规模化和集约化发展,抗生素作为疾病预防与治疗药物、生长促进剂、饲料添加剂等被广泛用于畜禽养殖和水产养殖业中,进而进入水环境和土壤环境,被农作物根系吸收进入茎、叶中并在植物体内富集,从而通过食物链进入人体内。近年来研究者对农作物中抗生素的研究逐渐增多。目前对农作物中兽用抗生素残留的前处理技术主要包括Qu ECh ERs方法和固相萃取法,检测技术主要包括高效液相色谱法、高效液相色谱-串联质谱法和酶联免疫法。高效液相色谱-串联质谱法具有高灵敏度、高选择性和高准确度,可同时快速测定多个目标物,更适合农作物中兽用抗生素残留的检测。本文对环境中抗生素的来源、农作物中抗生素污染的现状、抗生素残留检测的提取、净化方法以及检测方法的研究进展进行了综述。     

Geospatial analysis for utilizing the marginal land in regional biofuel industry: A case study in Guangdong Province,China

Due to the intensive and exhaustive land use in China, the so-called marginal land is expected to play a major role in supporting the biofuel industry of the country. We developed a regional-level framework of using geospatial information technologies to achieve an optimal utilization of the marginal land for biofuel production. The framework includes identifying marginal lands, evaluating optimality of the land for growing certain bioenergy crops, estimating local potential feedstock production, and finally selecting optimal sites for biofuel factories. We present a case study of farming Jatropha (Jatropha curcas L.) and Cassava (Manihot esculenta Crantz) in Guangdong, China. The marginal land was identified from satellite imageries at a 30-m resolution. The optimality for growing the two species was evaluated using the Ecological Niche Models (ENMs), which incorporates local temperature, precipitation, soil, and terrain. The optimality value was then converted into potential feedstock production using a conversion model. The site selection for the factories incorporated the local potential feedstock production, the transportation cost measured by road distance, and the farming cost related to the land patch geometry. Each candidate site received an overall optimality score derived based on those factors. We identified five sites that have high scores and also minimal or none spatial overlaps of their supporting areas. Three of them (Zhanjiang, Yunfu, and Jieyang) are for Cassava, located on in southern Guangdong. Two (Qingyuan and Meizhou) are for Jatropha in northern Guangdong.     

国内外主要粟类作物的种植、研究及产业化概况（网络首发、推荐阅读）

粟类作物是一类籽粒小、抗旱、耐贫瘠的一年生作物的统称，多种植和消费在亚洲和非洲的发展中国家，我国栽培面积比较大的是谷子和糜子。与种植和消费情况不同，亚洲、欧洲和美洲相对发达国家的政府更重视粟类作物的科学研究及其科研投入。我国国家自然科学基金资助发表的粟类研究论文居世界之首，欧洲委员会、英国研究与创新署、美国国家科学基金会资助的粟类研究论文数量排名紧跟其后。梳理了近5年发表的粟类科研论文，印度最多，其次是我国和美国。基于粟类作物富含膳食纤维、蛋白质、矿物质、多酚等，其具有多方面的健康功效，因此粟类的食品科学技术和植物科学成为最热的研究领域。最后阐述了国内外传统的和工业化的粟类产品情况。     

Some physiological characteristics to estimate species potential as a mine reclamation ground cover

In finding what physiological characteristics can be used to predict ground cover success on mine reclamation sites, 14 herb and grass species were tested. Establishment and early growth was tested on three different soils, ie vermiculate and quartz sand mixture, quarry overburden and coal mine overburden in a greenhouse. The results indicate that plant height and cover, transpiration rate and foliar pigments may be used to select plant adaptability to mined soil. White clover (Trifolium repens L.) showed the greatest potential as ground cover for mined soils. Species most widely used in reclamation tended to be perennials of moderate rate.     

Biogas production from catch crops: Increased yield by combined harvest of catch crops and straw and preservation by ensiling

The combination of catch crop cultivation with its use for biogas production would increase renewable energy production in the form of methane, without interfering with the production of food and fodder crops. The low biomass yield of catch crops has been shown as the main limiting factor for using these crops as co-substrate in biogas plants, since the profit obtained from the sale of methane barely compensates the harvest costs. Therefore, a new agricultural strategy to harvest catch crops together with the residual straw of the main crop was investigated, in order to increase the biomass and the methane yield per hectare. Seven catch crops harvested together with stubble from the previous main crop were evaluated. The effects of stubble height, harvest time and ensiling as a storage method for the different catch crops/straw blends were studied. Biomass yields as TS ranged between 3.2 and 3.6 t ha⁻¹ y⁻¹of which the catch crop constituted around 10% of the total biomass yield. Leaving the straw on the field until harvest of the catch crop in the autumn could benefit methane production from the straw both due to increased biomass yield and an increased organic matter bioavailability of the straw taking place on the field during the autumn months. Ensiling as a storage method could be feasible in terms of energy storage and guaranteeing the feedstock availability for the whole year. This new agricultural strategy may be a good alternative for economically feasible supply of catch crops and straw for biogas production.     

The attitudes of French and Spanish winegrowers towards the use of cover crops in vineyards

Vineyards are an intensive cultivation system and expose the soil to long-lasting stress. Many vineyard areas already show high degrees of soil degradation. To prevent further soil erosion, cover crops, which have various positive effects on the environment, are highly recommended. But, depending on the climatic conditions, cover crops can reduce grape yields and are sometimes more work intensive than bare soil management. In some areas cover crops are already widespread while in others bare soil is dominant. In this qualitative study, we explore the attitudes of European winegrowers towards cover crops and determine the background for differences in the adoption of greened vineyards. Thus, we conducted focus groups with winegrowers in two different regions, namely Coteaux du Layon in France and Montilla-Moriles in Spain. In this setting, the transregional differences are mainly based on the climatic conditions but also on different business structures and knowledge levels. Direct sellers seem to be more attentive to the environment and use cover crops more often than farmers which sell their grapes to cooperatives.     

A review of varietal change in roots,tubers and bananas: consumer preferences and other drivers of adoption and implications for breeding

This review of the literature on varietal change in sub-Saharan Africa looks in detail at adoption of new varieties of bananas in Uganda, cassava in Nigeria, potato in Kenya, sweetpotato in Uganda and yams in Côte d’Ivoire. The review explored three hypotheses about drivers of varietal change. There was a strong confirmation for the hypothesis that insufficient priority given to consumer-preferred traits by breeding programmes contributes to the limited uptake of modern varieties (MVs) and low varietal turnover. Lack of evidence meant the second hypothesis of insufficient attention to understanding and responding to gender differences in consumer preferences for quality and post-harvest traits was unresolved. The evidence on the third hypothesis about the informal seed system contributing to slow uptake of MVs was mixed. In some cases, the informal system has contributed to rapid uptake of MVs, but often it appears to be a barrier with inconsistent varietal naming a major challenge.     

面向深度学习识别高空农作物的方法

为探讨深度学习技术运用于高空或卫星图像处理的问题,针对其高空层次特征丰富但细节信息不充分,以及背景多元化干扰等特点,研究一种有效的多分类方法。利用消费级无人机采集农作物高空图像,从图像数据规模有限,较难实现有效训练的问题出发,提出一种综合数据增强和迁移学习的方法克服数据集不足;结合高空图像的独特特征,改进高维空间的最优分类函数,对模型进行优化,使之更吻合高空拍摄农作物图像的识别与处理。通过构建多组数据、多种模型的对比实验,验证了该方法的有效性与性能,为农业智慧决策提供有益补充。