1,721,071 research outputs found
Effects of four cultivation systems for maize on nitrogen leaching: II model simulations
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Soil pore system evaluated from gas measurements and CT images: A conceptual study using artificial, natural and 3D-printed soil cores
Full text linkCombining digital imaging, physical models and laboratory measurements is a step further towards a better understanding of the complex relationships between the soil pore system and soil functions. Eight natural 100-cm3 soil cores were sampled in a cultivated Stagnic Luvisol from the topsoil and subsoil, which we assumed had contrasting pore systems. Artificial 100-cm3 cores were produced from plastic or from autoclaved aerated concrete (AAC). Eight vertical holes of each diameter (1.5 and 3 mm) were drilled for the plastic cylinder and for one of the two AAC cylinders. All natural and artificial cores were scanned in an X-ray CT scanner and printed in 3D. Effective air-filled porosity, true Darcian air permeability, apparent air permeability at a pressure gradient of 5 hPa and oxygen diffusion were measured on all cores. The active pore system characteristics differed between topsoil (sponge-like, network of macropores of similar size) and subsoil (dominated by large vertical macropores). Active soil pore characteristics measured on a simplified pore network, that is, from artificial and printed soil cores, supported the fundamental differences in air transport by convection and diffusion observed between top- and subsoil. The results confirm the suitability of using the conceptual model that partitions the pore system into arterial, marginal and remote pores to describe effects of soil structure on gas transport. This study showed the high potential of using 3D-printed soil cores to reconstruct the soil macropore network for a better understanding of soil pore functions
Degradation of soil fertility can cancel pollination benefits in sunflower
No full textPollination and soil fertility are important ecosystem services to agriculture but their relative roles and potential interactions are poorly understood. We explored the combined effects of pollination and soil fertility in sunflower using soils from a trial characterized by different long-term input management in order to recreate plausible levels of soil fertility. Pollinator exclusion was used as a proxy for a highly eroded pollination service. Pollination benefits to yield depended on soil fertility, i.e., insect pollination enhanced seed set and yield only under higher soil fertility indicating that limited nutrient availability may constrain pollination benefits. Our study provides evidence for interactions between above- and belowground ecosystem services, highlighting the crucial role of soil fertility in supporting agricultural production not only directly, but also indirectly through pollination. Management strategies aimed at enhancing pollination services might fail in increasing yield in landscapes characterized by high soil service degradation. Comprehensive knowledge about service interactions is therefore essential for the correct management of ecosystem services in agricultural landscapes. © 2015, Springer-Verlag Berlin Heidelberg
Examining conservation agriculture soil profiles: Outcomes from northeastern Italian silty soils combining indirect geophysical and direct assessment methods
No full textConservation agriculture (CA) is an agronomic system, including no-tillage, cover crops and residue retention on the soil surface, which represents more sustainable management compared to conventional ploughing systems (CV). Conservation agriculture is widespread in some parts of the world (i.e. South America and the USA), whereas it is still developing in others (i.e. Europe). One of the main reasons for the slow European uptake of CA is low yield because of the worsening of soil physical quality, in particular increased compaction and reduced hydraulic permeability. The effects of CA on soil physical dynamics are poorly documented, particularly during the transition phase between CV and CA and for fine-textured soils. Therefore, in this study, the effects of CA on soil volumetric water content, bulk density, penetration resistance and electrical resistivity are presented over a 3-year monitoring period. The experiment was established in 2010 on four farms in the Veneto region (northeastern Italy) with silty soils, where CA practice was compared with CV. The dynamics of soil physical properties were monitored from 2014 to 2016 following a 3-year crop rotation cycle. Every year, bulk density analysis, a penetration resistance test and three-dimensional electrical resistivity tomography were performed. The results showed that soil physical properties clustered depending on soil texture: in silty loam soils any specific improvements were highlighted after 6 years of CA, whereas in loamy soils soil compaction was observed in both CA and CV. Indeed, CA resulted in soil compaction below a depth of 10 cm (+107% of degree of compaction), whereas CV resulted in the formation of a plough pan in the 35–55-cm layer (+111% of degree of compaction). The low soil organic carbon and low clay contents made loamy soil particularly prone to compaction, highlighting the influence of fine texture on soil structure evolution during the transition phase
Preferential solute transport under variably saturated conditions in a silty loam soil: Is the shallow water table a driving factor?
No full textA shallow water table might enhance preferential solute movement by modifying both the water flow and solute
dynamics. In this study, we estimated soil hydraulic and solute transport parameters through a tracer experiment
in lysimeters comparing different water table levels. In a set-up of 12 lysimeters, the bottom boundary condition
was set as a water table depth of 120 cm, or 60 cm, or as free drainage. A tracer solution of bromide (250 mg l 1,
40 mm) was added to each lysimeter and soil water was sampled with suction cups at different depths for the
following 174 days. Soil water content and matric potential were monitored using TDR probes and electronic
tensiometers at the same depths. Soil hydraulic and solute transport parameters in different soil layers were
estimated by inverse modeling using HYDRUS 1D. Soil hydraulic parameters were estimated from the Mualemvan
Genuchten equations, while both the advection–dispersion (ADE) and physical non-equilibrium mobileimmobile
water (MIM) models were used to describe the solute transport. Moreover, the soil pore network was
analyzed by means of 3D X-ray microtomography. Results showed different solute dynamics between contrasting
water table managements. With free drainage, solute in the immobile domain was negligible, and its transport
was fully associated with the mobile water flow. In contrast, a shallow water table affected the tracer transport,
by modifying a) the soil pore network, with an increase of the macropores and a reduction of the pore connectivity;
b) the flow field, with an increase of immobile water and a reduction of αMIM, indicating slow exchange
between mobile and immobile regions, in turn promoting preferential pathways. Hence, groundwater pollution
might be worsened by preferential solute transport of agrochemicals occurring with shallow water table
conditions
Integrated Pest Meadow-ploughing timing as an integrated pest management tactic to prevent soil-pest damage to maize
No full textThe management of soil-pests still largely relies on conventional chemical insecticides despite the provisions of Integrated Pest Management (IPM). Long-term research was carried out in north-eastern Italy to assess the potential of meadow ploughing just before maize sowing to prevent wireworm damage. The research was based on the observation that no serious wireworm damage occurred in 20 years when meadows were ploughed just before maize sowing. The research hypothesis was that soil-incorporated fresh meadow turf would be a more attractive wireworm food source than seeds, emerging seedlings and young plants. Meadow plots with a sufficiently homogeneous wireworm density were alternately ploughed the previous autumn and a few days before maize sowing. The same conditions were simulated in pots into which known numbers of cage-reared wireworms had been introduced. Results showed very consistently that plant damage in plots ploughed just before maize sowing was much lower than the damage in plots ploughed in autumn-winter, and always below the economic risk threshold (15% of damaged plants). In controlled conditions, plant damage in pots with soil-incorporated fresh meadow turf was significantly lower than that observed in pots without. In both field and controlled conditions, this major effect on plant protection is likely to be caused by the incorporation of meadow turf living plant parts into the soil. Therefore, the ploughing timing of meadows in rotation may be a viable alternative to chemical insecticides when rotation includes meadow
Trade-offs among ecosystem services advance the case for improved spatial targeting of agri-environmental measures
No full textAgri-environmental measures (AEMs) are meant to foster environmentally-friendly farming techniques. The use of AEMs to enhance agroecosystem quality is still under debate due to site-specific spatial mismatches that often occur between adopted AEMs and delivered ecosystem services. Here, a site-specific approach was employed to assess the advantages and disadvantages of AEMs adopted from the Rural Development Programme and applied in the Veneto Region (NE Italy) during 2014–2020. Specifically, a DayCent model-GIS platform compared business-as-usual (BAU) and AEM scenarios. The effect of AEMs on ecosystem services was assessed by integrating high-resolution spatial data from multiple pedo-climates and land managements and combined agronomic and environmental outcomes. Results showed that AEM adoption generally improved ecosystem service delivery, especially by reducing water pollution and increasing soil fertility. Among simulated practices, permanent soil cover and minimum soil disturbance (i.e., conservation agriculture, pasture and meadow maintenance) produced the best results across the Veneto Region, despite compromises in agronomic performance due to AEM-specific commitments (e.g., narrow crop rotation in conservation agriculture, fertilizer use restrictions in pastures and meadows). Other AEMs (e.g., organic farming) appeared highly dependent on their spatial distribution and were influenced by a strong interaction between pedo-climatic characteristics (e.g., soil properties) and management techniques (e.g., type and quantity of nutrients input). The spatial-target approach is highly recommended to identify AEMs that achieve environmental quality objectives and develop indications as to where they should be encouraged to maximize ecosystem services delivery
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