Mycorrhiza induced resistance in potato plantlets challenged by Phytophthora infestans

Biological control of soil-borne pathogens by arbuscular mycorrhizal (AM) fungi has been repeatedly demonstrated. However, their role in the control of above-ground hemibiotrophic pathogens is less conclusive. Here, we investigated in vitro the impact of an AM fungus on Phytophthora infestans in potato plants. The leaf infection index was decreased in mycorrhizal potato plants. Real-Time Quantitative PCR revealed the induction of two pathogenesis related genes (PR1 and PR2) in the leaves of mycorrhizal plants shortly after infection with P. infestans. These results suggested a systemic resistance in mycorrhizal plants, related to the priming of the two PR genes in potato.     

Breeding Differently: Participatory Selection and Scaling Up Innovations in Colombia

Global challenges like sustainable development, climate change, malnutrition and gender inequality can be tackled from an agricultural perspective. Micronutrient deficiency is a major problem for the health and food security of the population. In Colombia, iron deficiencies affect 32% of the children under the age of five; and 43% of the Colombian population have zinc and vitamin A deficiencies. We designed and implemented a research-for-development programme that links agriculture and nutrition through a two-stage project. In the first stage, we selected three new yellow potato cultivars with better nutritional contents, higher yield and better resistance to late blight than the traditional yellow cultivars. We characterized the Colombian germplasm, Solanum tuberosum Group Phureja, for its nutritional attributes. During this stage, studies of the social and nutritional status of the communities were also conducted. In the second stage, we focused on scaling up new potato cultivars to reach potato producers and consumers by promoting the production and marketing of good quality seed potatoes, by establishing four Rural Entrepreneurs Nuclei. The programme promotes gender equity, good dietary habits, the consumption of more nutritious potatoes and empowers local leadership to strengthen governance. Field work was conducted in southern and central regions of Colombia by employing social strategies such as the Family Farming Community Schools. In 50% of the cultivated area, we are replacing the originally used traditional yellow potatoes by the new, more nutritious, potatoes to reach 6 million consumers. A good quality seed system for small-scale potato growers has been implemented. These achievements have been reached through a comprehensive approach in a period of two years.     

Afforestation of agricultural land with Pinus radiata D. don and Betula alba L. in NW Spain: Effects on soil PH,understorey production and floristic diversity eleven years after establishment

Afforestation of abandoned agricultural lands has been the main change in land use over the past decade in Europe. However, the impact of tree species and understorey management on production and plant diversity over the medium‐ and long‐term has not been thoroughly studied. This paper aims to evaluate the effects of an afforestation of Pinus radiata D. Don and Betula alba L. on soil pH, understorey production and plant diversity and life cycle type (annuals vs. perennials) managed with different soil fertilisation treatments over a period of 11 years. The results show an acidification of the soil 11 years after establishment, better vertical growth and diameter of pine compared with birch as usually happens in the region and important variation in the biomass production and composition of the understorey below both tree species. Understorey species remained similar during the first 5 years below both canopies. However, species richness (S) was drastically reduced under Pinus radiata D. Don plantation compared to Betula alba L. (S_pine = 2 vs. S_birch = 17) after 11 years of tree establishment at a very high density (2500 trees ha⁻¹). Inorganic and organic fertilisation also caused a reduction in floristic diversity. Soil pH, pasture production and floristic understorey plant diversity are better preserved under autochthonous broadleaves, which increased the multiple uses of recently afforested lands in the short‐ and medium‐term. In the European context of high need for sawn wood, the use of autochthonous broadleaved tree species like Betula should be promoted due to their better sustainability. Copyright © 2011 John Wiley & Sons, Ltd.     

Identification of New Betalains in Separated Betacyanin and Betaxanthin Fractions from Ulluco (Ullucus tuberosus Caldas) by HPLC-DAD-ESI-MS

Plant Foods for Human Nutrition - An improved methodology of achieving an accurate separation of pure fractions of betacyanins and betaxanthins from Ullucus tuberosus Caldas has been carried out....     

First report of Bursaphelenchus mucronatus kolymensis (Nematoda: Aphelenchoididae) on Monochamus sutor (Coleoptera: Cerambycidae) in Spain

This is the first report of Monochamus sutor as vector of B. mucronatus kolymensis, the European type of B. mucronatus (synonymous with B. kolymensis) in Spain. In 2013, a female of Monochamus sutor was caught in a Pinus sylvestris forest. Nematode species identification was based on morphological characteristics and on molecular and phylogenetic analysis of dauer juveniles and adults.     

Soil,crop and emission responses to seasonal-controlled traffic in organic vegetable farming on loam soil

Some organic arable and vegetable farms in the Netherlands use cm-precise guidance of machinery to restrict wheel traffic to fixed traffic lanes and to achieve non-trafficked cropping zones with optimized soil structure in between the lanes. Contrary to controlled traffic farming (CTF) the traffic lanes are not yet used for harvesting and primary tillage. Therefore, the system is called a seasonal-controlled traffic farming (SCTF) system. A field experiment was conducted on an organic vegetable farm to reveal soil, crop and emission responses of SCTF with traffic lanes at 3.15-m centres compared with conventional random traffic farming (RTF) using low ground pressures in spring from 2002 till 2005. The traffic systems were investigated in the crops green pea (Pisum sativum L.), spinach (Spinacea oleracea L.), onions (Allium cepa L.) and carrots (Daucus carota L.). Compared with RTF, the topsoil structure in the SCTF system improved for the crops sown on the flat but not for carrot grown on ridges. Crop yields increased significantly in green pea, spinach and planted onion sets but not in carrot and direct-sown onion. The available N-min at the end of the cropping period was not different between systems and, therefore, leaching losses in winter are expected to be the same. SCTF resulted in a significant reduction of N₂O emissions (by 20–50% compared to RTF). For CH₄, application of the SCTF system resulted in increased CH₄ uptake (by a factor 5–20) compared to the RTF system in three of the four measured fields. At the fourth field, lower (but not significant) CH₄ emissions (by a factor 4) were measured in the SCTF system compared to RTF. Effects of SCTF on timeliness and on the economic feasibility are discussed.     

Estimating ammonia emission after field application of manure by the integrated horizontal flux method: a comparison of concentration and wind speed profiles

The integrated horizontal flux method is commonly used to estimate ammonia emission from field-applied manure. The method involves measuring the wind speed and ammonia concentration at various heights on a post in the middle of a manured plot. Wind speed and concentration profiles are subsequently fitted to these measurements. The product of the profiles represents the amount of ammonia displaced by the wind, and the calculated ammonia emission is based on integrating the product of the profiles along the height. A crucial step is the functional form of the profiles, and linear relationships employing the logarithm of the height are generally used. In this study, 160 Dutch emission experiments on grassland were re-analysed to evaluate alternative profiles for the concentration and wind speed. It is shown that an exponential concentration model usually provides a better fit than the commonly used profile and that the measurement error for the concentration should be modelled by means of a gamma distribution. Based on the re-analysis, this new model reduces the calculated ammonia emission by around 10%. It is further shown that adding a displacement parameter to the wind speed model only has a minor effect on the calculated emission. Finally, a simulation study reveals that misspecification of the concentration profile may lead to a relative bias of up to 27%, that the precision of the estimated emission can be improved by increasing the number of concentration measurements near the ground and that wind speed measurements at three heights could suffice.     

Carbon replacement and stability changes in short-term silvo-pastoral experiments in Colombian Amazonia

There is little information on the effects of land use change on soil Carbon stocks in Colombian Amazonia. Such information would be needed to assess the impact of this area on the global C cycle and the sustainability of agricultural systems that are replacing native forest. The aim of this study was to evaluate soil carbon stocks and changes after the clearing of the native forest, the establishment of pastures and the reclamation of the degraded pasture, in Caquetá, Colombia.We compared the contents of Total C, Oxidizable C and Non-Oxidizable (stable) C in four different land use systems, namely Monoculture (Brachiaria grassland), Association (Brachiaria + Arachis pintoi), Forage Bank (a mixture of forage tree species), and Natural Regeneration of the pasture in both a flat area and a sloping one. The Degraded Pasture was the reference.Results showed that in the sloping area all treatments have higher Total Carbon stocks than the Degraded Pasture, while three of the treatments significantly increased the stocks of Non-Oxidizable C.In the flat landscape, only the Association significantly increased Total C stocks. Plowing and fertilization cause significant increases in Oxidizable carbon and decreases in Non-Oxidizable carbon. This effect needs further research, as C stability will influence equilibrium stocks.In the sloping area, improved pastures and fodder bank rapidly increased Total Carbon contents and stocks, with increases as large as10 ton.ha^?1 yr^?1. In the Traditional Fodder Bank, which showed the largest increase, this is partially due to the application of organic manure. Surprisingly, also C stocks under Natural Regeneration were significantly higher than under the original Degraded Grassland. This increase was fully due to Non-Oxidizable Carbon, which is difficult to explain.Stable isotope analysis indicated that under improved grassland, especially Brachiaria monoculture, up to 40% of the original C in the upper 10 cm was replaced in 3.3 years.     

Effects of lime and sewage sludge on soil,pasture production,and tree growth in a six‐year‐old Populus canadensis Moench silvopastoral system

In many regions worldwide, silvopastoral systems are implemented to enable sustainable land use allowing short, medium, and long‐term economic returns. However, the short‐term production in silvopastoral systems is often limited due to nonappropriate soil‐fertility management. This study evaluated the effects of two doses of lime (0 and 2.5 t CaCO₃ ha^–1) and three sewage‐sludge treatments (0, 200, and 400 kg total N ha^–1 y^–1 applied in 2 consecutive years) on soil characteristics (soil pH, soil organic matter [SOM], soil nitrogen, cation‐exchange capacity [CEC]), pasture production, and tree growth in a silvopastoral system of Populus × canadensis Moench in Galicia, northern Spain during 6 years after establishment. Soil pH increased during the experimental period for all treatments, although this effect was more pronounced after lime application. Changes in SOM and soil nitrogen content were not consistent over time, but sewage‐sludge application seemed to result in higher values. Higher CEC was found for treatments with lime and sewage‐sludge application. Following incorporation of lime and sewage sludge, pasture production was significantly enhanced (cumulative pasture production 51.9 t DM ha^–1 for Lime/N400 compared to 39.0 t DM ha^–1 for No lime/N0). This higher pasture production also affected tree growth due to more severe competition between pasture and tree resulting in slower tree growth. Liming and application of sewage sludge are relevant measures to improve soil fertility and thereby optimizing the overall production of silvopastoral systems. However, it is important not to overintensify pasture production to ensure adequate tree growth.