A1-512 Efecto del laboreo mínimo sobre el rendimiento, la abundancia de la flora arvense y el balance energético y económico en una rotación de espelta, garbanzos y trigo en la Región Mediterránea

El laboreo mínimo en sistemas herbáceos extensivos ecológicos en Europa, se ha llevado a cabo sobre todo en climas templados. El equipo de investigación Ecología de los Sistemas Agrícolas de la Universidad de Barcelona estableció un experimento a largo plazo en 2011 que tiene el objetivo de evaluar la viabilidad del laboreo mínimo en cultivos herbáceos extensivos ecológicos en clima mediterráneo. Este trabajo analiza el efecto del tipo de laboreo y la fertilización con estiércol compostado sobre el rendimiento de los cultivos de cereales y leguminosas, la abundancia de la flora arvense y el balance económico y energético. El laboreo mínimo no afectó los rendimientos de los cultivos y la fertilización favoreció a los cultivos de cereales. Los balances económico y energético no mostraron diferencias significativas con el tipo de laboreo ni con la fertilización, con la excepción de una mayor cantidad de salida de energía en las parcelas fertilizadas en el cultivo de trigo

Efecto del laboreo mínimo (chisel), la fertilización y los abonos verdes sobre la flora arvense y los rendimientos en una rotación de cultivos de cereales y leguminosas ecológicos

Effects of reduced tillage, fertilization and green manures on the weeds and crop yields in a cereal-legume crop rotation under organic farming. On 2011, we established a long-term experiment to evaluate the effects of reduced tillage (chisel vs mouldboard plough), fertilization with semicomposted manure and sowing of green manures before spring crops, on the crop yields and weed abundance in a 5-year rotation (spelt, chickpea, wheat, lentil and spelt). After five years, there was not noticeable increment in weed abundance or richness. Reduced tillage caused a significant increase of weeds compared with mouldboard plough, but it this increase did not cause significant yield loss in cereal crops compared with mouldboard plough. Green manures exerted a strong weed suppression, although this effect did not persist on the subsequent (legume) crop. Entre 2011 y 2016 se realizó un experimento para evaluar el efecto del laboreo mínimo (chisel) respecto a arado de vertedera, de la fertilización con estiércol y de la siembra de abonos verdes antes de los cultivos de primavera, sobre los rendimientos del cultivo y la abundancia de las malas hierbas, en una rotación de 5 años (espelta, garbanzo, trigo, lenteja y espelta). El laboreo mínimo provocó un aumento significativo de las arvenses pero sin conllevar pérdidas significativas en los rendimientos de los cereales respecto a los rendimientos con el arado de vertedera. El abono verde ejerció un fuerte control sobre las malas hierbas, aunque este efecto no persistió durante el cultivo de la leguminosa inmediatamente posterior

Crop yield, weed infestation and soil fertility responses to contrasted ploughing intensity and manure additions in a Mediterranean organic crop rotation

Conservation agriculture and organic farming are two alternative strategies that aim to improve soil quality and fertility in arable cropping systems through the deployment of different practices, that are rarely combined. While conservation agriculture practices include reducing tillage intensity and maintaining soil cover all year round to prevent soil erosion, organic farming focuses on nutrient recycling, using farmyard manure and green manure to enhance soil quality. However, these practices are not free from side-effects, such as increasing weed infestation or limited nutrient availability. Therefore it is necessary to explore the sustainability of their combination under local environmental constraints. The objectives of this study were to evaluate the effects of tillage type (mouldboard vs. chisel ploughing), fertilization and green manure on soil parameters (SOC, N, bulk density, carbon stocks, and soil microbial biomass Cmic and Nmic), weed abundance and crop yields in a four-year rotation of spelt, chickpea, winter wheat and lentil in the Mediterranean region (Catalonia, Spain). Tillage and green manure did not affect crop yields or weed biomass, although during the last year of the experiment, plots with mouldboard ploughing had less weed biomass and higher lentil biomass. Fertilization was the most important factor, increasing the cereal yields, SOC, N and soil microbial biomass (Cmic and Nmic) content of the soil. However, fertilization did not favour chickpea and lentil crops because weed competition limited legume crop growth. Overall, there was a loss of SOC and a reduction of carbon stocks over the four years of the trial in the soil because of the deep soil tillage (25 cm) and low crop productivity irrespective of tillage type. In contrast, N content increased in all of the plots and was enhanced by fertilization. The use of chisel plough stratified the distribution of SOC and N in the surface layers (0-10 cm). Both Cmic and Cmic/SOC ratio increased in fertilized treatments, suggesting an increased lability of SOC. The application of more stabilized organic matter may be a better practice to build up soil organic matter and to maintain crop yields in organic farming systems

The Gallecs trial, a mid-term experiment on reduced tillage, fertilisation and green manure in Mediterranean dryland arable cropping systems

Conservation agriculture and organic farming are two alternative strategies aimed at improving soil fertility in arable cropping systems through reducing tillage intensity, maintaining year-round soil cover and increasing nutrient recycling, using farmyard and green manures. However, the reduction of tillage intensity can increase weed infestation and decrease nutrient availability. The mid-term "Gallecs" trial (Catalonia) was established in autumn 2011 at Gallecs, a periurban agricultural area near Barcelona. The effects of tillage (mouldboard versus chisel ploughing), fertilisation by farmyard manure (without versus with) and green manure (without versus with) on soil fertility indicators, weed abundance and grain crop yields were studied in a 4-years cereal-legume rotation for human consumption under organic farming conditions in the Mediterranean region (Catalonia, Spain)