Local management and landscape drivers of pollination and biological control services in a Kenyan agro-ecosystem

Arthropods that have a direct impact on crop production (i.e. pests, natural enemies and pollinators) can be influenced by both local farm management and the context within which the fields occur in the wider landscape. However, the contributions and spatial scales at which these drivers operate and interact are not fully understood, particularly in the developing world. The impact of both local management and landscape context on insect pollinators and natural enemy communities and on their capacity to deliver related ecosystem services to an economically important tropical crop, pigeonpea was investigated. The study was conducted in nine paired farms across a gradient of increasing distance to semi-native vegetation in Kibwezi, Kenya. Results show that proximity of fields to semi-native habitats negatively affected pollinator and chewing insect abundance. Within fields, pesticide use was a key negative predictor of pollinator, pest and foliar active predator abundance. On the contrary, fertilizer application significantly enhanced pollinator and both chewing and sucking insect pest abundance. At a 1 km spatial scale of fields, there were significant negative effects of the number of semi-native habitat patches within fields dominated by mass flowering pigeonpea on pollinators abundance. For service provision, a significant decline in fruit set when insects were excluded from flowers was recorded. This study reveals the interconnections of pollinators, predators and pests with pigeonpea crop. For sustainable yields and to conserve high densities of both pollinators and predators of pests within pigeonpea landscapes, it is crucial to target the adoption of less disruptive farm management practices such as reducing pesticide and fertilizer inputs.

Plant and invertebrate resources for farmland birds in pastoral landscapes

On 16 UK livestock holdings within pastoral landscapes, we investigated the provision of plant and invertebrate resources for farmland birds in spring barley and winter wheat cereal-based whole crop silages as alternatives to maize and grass silages. The benefits of low input barley systems were also investigated; barley fields were subjected to two separate herbicide sub-treatments on a split-field design (high input broad-spectrum or low input narrow spectrum herbicides). The abundance of plant resources and invertebrates was assessed for three growing seasons during summer and winter for each crop type. The study clearly demonstrated the value of spring barley for the provision of plant resources when compared to the other silage cropping systems, whilst invertebrate responses were variable. No differences in plant and invertebrate resources were found between the barley treatments. Throughout the year, forage maize afforded the lowest provision of resources for farmland birds, and because it is likely that maize will continue to be grown in pastoral areas, the value of this habitat needs to be improved if farmland birds are to benefit. To provide plant and invertebrate resources for farmland birds in pastoral landscapes we strongly advocate the growing of spring sown barley whole-crop silage followed by over-wintering stubbles. © 2011 Elsevier B.V. All rights reserved.

Barbara Torelli Benedetti, Partenia, a pastoral play. A bilingual edition edited with notes and translation

This edition presents for the first time in print what is probably the earliest known secular, 'regular' play by a woman in Italy. As suggested in the introduction to the work, Torelli's play offers a fascinating example of female dramaturgy and creative adaptation of the pastoral genre in the context of late sixteenth-century Parma. Critical textual study is combined with new biographical material on the author and her literary milieu. The edition provides the first detailed palaeographical study of the complex Cremona manuscript of the play, which unusually includes emendations thought to be in the hand of the author herself (besides others). The transcription also describes for the first time in detail a newly discovered second manuscript of the play in Rome. The play-text is presented in the original Italian with a new facing English translation. Also included is the first transcription of the paratextual verse from the Cremona manuscript and the first transcribed collection of the author’s extant verse (both with translation).

Is a native rodent competitively dominant over an invasive rodent in lowland agro-forest habitat of the Philippines?

In the lowland agro-forest of the Sierra Madre Biodiversity Corridor (SMBC), it is considered that a native rodent species, Rattus everetti is competitively dominant over an invasive pest species, Rattus tanezumi. The main aim of this study was to assess the response of R. tanezumi following short term removal of R. everetti. We tested this experimentally by trapping and removing R. everetti from two treatment sites in agro-forest habitat on three occasions over three consecutive months. This was followed by three months of non-removal trapping. Two non-treatment sites were trapped for comparison. Following R. everetti removal, R. everetti individuals rapidly immigrated into the treatment sites and a significantly higher proportion of R. tanezumi females were in breeding condition in the treatment sites than in the non-treatment sites. The results from this study provide evidence of competition between native and invasive rodent species in complex agro-ecosystems. We were also able to demonstrate that R. everetti populations are able to recover rapidly from the non-target effects of short-term lethal control in and around agro-forest.

An easily implemented agro-hydrological procedure with dynamic root simulation for water transfer in the crop-soil system: validation and application

Models for water transfer in the crop-soil system are key components of agro-hydrological models for irrigation, fertilizer and pesticide practices. Many of the hydrological models for water transfer in the crop-soil system are either too approximate due to oversimplified algorithms or employ complex numerical schemes. In this paper we developed a simple and sufficiently accurate algorithm which can be easily adopted in agro-hydrological models for the simulation of water dynamics. We used a dual crop coefficient approach proposed by the FAO for estimating potential evaporation and transpiration, and a dynamic model for calculating relative root length distribution on a daily basis. In a small time step of 0.001 d, we implemented algorithms separately for actual evaporation, root water uptake and soil water content redistribution by decoupling these processes. The Richards equation describing soil water movement was solved using an integration strategy over the soil layers instead of complex numerical schemes. This drastically simplified the procedures of modeling soil water and led to much shorter computer codes. The validity of the proposed model was tested against data from field experiments on two contrasting soils cropped with wheat. Good agreement was achieved between measurement and simulation of soil water content in various depths collected at intervals during crop growth. This indicates that the model is satisfactory in simulating water transfer in the crop-soil system, and therefore can reliably be adopted in agro-hydrological models. Finally we demonstrated how the developed model could be used to study the effect of changes in the environment such as lowering the groundwater table caused by the construction of a motorway on crop transpiration. (c) 2009 Elsevier B.V. All rights reserved.

Developing a reliable strategy to infer the effective soil hydraulic properties from field evaporation experiments for agro-hydrological models

The Richards equation has been widely used for simulating soil water movement. However, the take-up of agro-hydrological models using the basic theory of soil water flow for optimizing irrigation, fertilizer and pesticide practices is still low. This is partly due to the difficulties in obtaining accurate values for soil hydraulic properties at a field scale. Here, we use an inverse technique to deduce the effective soil hydraulic properties, based on measuring the changes in the distribution of soil water with depth in a fallow field over a long period, subject to natural rainfall and evaporation using a robust micro Genetic Algorithm. A new optimized function was constructed from the soil water contents at different depths, and the soil water at field capacity. The deduced soil water retention curve was approximately parallel but higher than that derived from published pedo-tranfer functions for a given soil pressure head. The water contents calculated from the deduced soil hydraulic properties were in good agreement with the measured values. The reliability of the deduced soil hydraulic properties was tested in reproducing data measured from an independent experiment on the same soil cropped with leek. The calculation of root water uptake took account for both soil water potential and root density distribution. Results show that the predictions of soil water contents at various depths agree fairly well with the measurements, indicating that the inverse analysis is an effective and reliable approach to estimate soil hydraulic properties, and thus permits the simulation of soil water dynamics in both cropped and fallow soils in the field accurately. (C) 2009 Elsevier B.V. All rights reserved.

A universal agro-hydrological model for water and nitrogen cycles in the soil-crop system SMCR_N: critical update and further validation

Agro-hydrological models have widely been used for optimizing resources use and minimizing environmental consequences in agriculture. SMCRN is a recently developed sophisticated model which simulates crop response to nitrogen fertilizer for a wide range of crops, and the associated leaching of nitrate from arable soils. In this paper, we describe the improvements of this model by replacing the existing approximate hydrological cascade algorithm with a new simple and explicit algorithm for the basic soil water flow equation, which not only enhanced the model performance in hydrological simulation, but also was essential to extend the model application to the situations where the capillary flow is important. As a result, the updated SMCRN model could be used for more accurate study of water dynamics in the soil-crop system. The success of the model update was demonstrated by the simulated results that the updated model consistently out-performed the original model in drainage simulations and in predicting time course soil water content in different layers in the soil-wheat system. Tests of the updated SMCRN model against data from 4 field crop experiments showed that crop nitrogen offtakes and soil mineral nitrogen in the top 90 cm were in a good agreement with the measured values, indicating that the model could make more reliable predictions of nitrogen fate in the crop-soil system, and thus provides a useful platform to assess the impacts of nitrogen fertilizer on crop yield and nitrogen leaching from different production systems. (C) 2010 Elsevier B.V. All rights reserved.

Assessing and monitoring impacts of genetically modified plants on agro-ecosystems: the approach of AMIGA project

The environmental impacts of genetically modified crops is still a controversial issue in Europe. The overall risk assessment framework has recently been reinforced by the European Food Safety Authority(EFSA) and its implementation requires harmonized and efficient methodologies. The EU-funded research project AMIGA − Assessing and monitoring Impacts of Genetically modified plants on Agro-ecosystems − aims to address this issue, by providing a framework that establishes protection goals and baselines for European agro-ecosystems, improves knowledge on the potential long term environmental effects of genetically modified (GM) plants, tests the efficacy of the EFSA Guidance Document for the Environmental Risk Assessment, explores new strategies for post market monitoring, and provides a systematic analysis of economic aspects of Genetically Modified crops cultivation in the EU. Research focuses on ecological studies in different EU regions, the sustainability of GM crops is estimated by analysing the functional components of the agro-ecosystems and specific experimental protocols are being developed for this scope.