L’integrazione del sovescio di veccia vellutata con compost arricchiti in fosforo aumenta la sostenibilità di un sistema colturale biologico senza produzione animale? Effetti sul mais e sulla vegetazione infestante

In un sistema colturale biologico senza produzione animale non irriguo, per poter incrementare la fertilità chimica, fisica e biologica dei terreni è opportuno poter disporre di strategie agronomiche integrate di gestione del suolo. Nel sistema colturale biologico oggetto di una ricerca di lungo periodo di confronto biologico-convenzionale (MASCOT) è stata rilevato un bilancio negativo del fosforo. Pertanto, al fine di preservare la fertilità del suolo nel lungo periodo, sono state individuate delle soluzioni tecniche per reintegrare le quantità di fosforo asportate e contemporaneamente incrementare la dotazione di azoto disponibile e di sostanza organica nel suolo. Lo scopo del presente lavoro è quello di valutare le possibili interazioni tra le tecniche agronomiche usualmente impiegate per migliorare la fertilità chimica, fisica e biologica dei sistemi colturali biologici, come il sovescio di leguminose, e soluzioni innovative come l’uso di compost arricchiti in fosforo

Innovative crop and weed management strategies for organic spinach: crop yield and weed suppression.

In organic agriculture, it is important to tackle crop and weed management from a system perspective to make it effective, especially in poorly competitive crops such as vegetables. For that reason, we developed two innovative integrated crop and weed management systems for a field vegetable crop sequence in a commercial organic farm that we have been comparing to a standard farm system from 2006 to 2008. The three systems are applied to a spinach-potato-cabbage-tomato two-year crop sequence and include different levels of technical innovation: Standard Crop Management System (SCMS); Intermediate Crop Management System (ICMS); and Advanced Crop Management System (ACMS). ICMS is based on a sequence of physical weed management treatments, whereas ACMS also includes a subterranean clover (Trifolium subterraneum) living mulch. In this paper we analyse the results obtained on spinach (Spinacia oleracea) in terms of crop yield and weed suppression. Both innovative systems increased total spinach fresh weight yield compared to SCMS, despite higher weed biomass. In ACMS, total weed biomass decreased linearly with increasing biomass of the subterranean clover living mulch

Innovative crop and weed management strategies for organic spinach: crop yield and weed suppression

In organic agriculture, it is important to tackle crop and weed management from a system perspective to make it effective, especially in poorly competitive crops such as vegetables. For that reason, we developed two innovative integrated crop and weed management systems for a field vegetable crop sequence in a commercial organic farm that we have been comparing to a standard farm system from 2006 to 2008. The three systems are applied to a spinach-potato-cabbage-tomato two-year crop sequence and include different levels of technical innovation: Standard Crop Management System (SCMS); Intermediate Crop Management System (ICMS); and Advanced Crop Management System (ACMS). ICMS is based on a sequence of physical weed management treatments, whereas ACMS also includes a subterranean clover (Trifolium subterraneum) living mulch. In this paper we analyse the results obtained on spinach (Spinacia oleracea) in terms of crop yield and weed suppression. Both innovative systems increased total spinach fresh weight yield compared to SCMS, despite higher weed biomass. In ACMS, total weed biomass decreased linearly with increasing biomass of the subterranean clover living mulch

Combining a weed traits database with a population dynamics model predicts shifts in weed communities

A functional approach to predicting shifts in weed floras in response to management or environmental change requires the combination of data on weed traits with analytical frameworks that capture the filtering effect of selection pressures on traits. A weed traits database (WTDB) was designed, populated and analysed, initially using data for 19 common European weeds, to begin to consolidate trait data in a single repository. The initial choice of traits was driven by the requirements of empirical models of weed population dynamics to identify correlations between traits and model parameters. These relationships were used to build a generic model, operating at the level of functional traits, to simulate the impact of increasing herbicide and fertiliser use on virtual weeds along gradients of seed weight and maximum height. The model generated ‘fitness contours’ (defined as population growth rates) within this trait space in different scenarios, onto which two sets of weed species, defined as common or declining in the UK, were mapped. The effect of increasing inputs on the weed flora was successfully simulated; 77% of common species were predicted to have stable or increasing populations under high fertiliser and herbicide use, in contrast with only 29% of the species that have declined. Future development of the WTDB will aim to increase the number of species covered, incorporate a wider range of traits and analyse intraspecific variability under contrasting management and environments

Direct weed suppression by cover crops and residual effects on grain maize and sunflower

We investigated the weed suppression potential of different winter cover crops grown alone or in mixtures during the cover crop growing cycle and in subsequent grain maize and sunflower. A plot trial was conducted in 2005-06 and 2006-07 at CIRAA (University of Pisa, Italy). The experiment was laid out as an RCB design. Data were subjected to ANOVA and subsequent LSD test at P ≤ 0.05 for mean separation. In both years there were significant differences between treatments in terms of cover crop and weed biomass. Leguminous cover crops produced the highest biomass, especially Vicia villosa when grown alone (5.3 and 5.7 t ha-1 in 2006 and 2007 respectively). In 2007 also cover crop mixtures gave good results with a mean biomass of 6.9 t ha-1. Mixtures were the most weed suppressive cover crops in both years, yielding on average 0.3 and 0.2 t ha-1 total weed biomass compared to an overall mean of 0.9 and 1.1 t ha-1 in 2006 and 2007 respectively. In both years, we registered the highest cash crop grain yield when maize or sunflower followed V. villosa or the mixtures including a leguminous cover crop. There were significant differences among treatments in terms of total weed biomass in the subsequent cash crops in 2006 but not in 2007. In sunflower, the lowest total final weed biomass was observed after the Avena sativa cover crop (0.4 t ha-1) whereas in maize the lowest weed biomass was observed after V. villosa (0.3 t ha-1)