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Les binadores són les màquines de desherbatge mecànic que permeten obtenir les eficàcies més altes en el control de les herbes del blat de moro (en condicions favorables, superiors al 70%). Consten d’un bastidor al qual s’acoplen cossos amb relles per treballar el terreny situat entre les línies del cultiu. La seva principal limitació és el control de les herbes situades dins i a prop de la fila del cultiu i sobretot l’eliminació de les espècies perennes. És una eina adequada per incorporar en les estratègies de desherbatge combinat mecànic i químic que permet la reducció de l’ús d’herbicides. Se’n pot augmentar la precisió amb la incorporació de l’autoguiatge SSNG RTK i/o càmeres o visors. Les binadores de precisió permeten una major velocitat de treball i un millor control de les herbes properes al cultiu. info:eu-repo/semantics/publishedVersion

info:eu-repo/semantics/publishedVersion

The emissions of nitrous oxide (N2O) and leaching of nitrate (NO3) from agricultural cropping systems have considerable negative impacts on climate and the environment. Although these environmental burdens are less per unit area in organic than in non-organic production on average, they are roughly similar per unit of product. If organic farming is to maintain its goal of being environmentally friendly, these loadings must be addressed. We discuss the impact of possible drivers of N2O emissions and NO3 leaching within organic arable farming practice under European climatic conditions, and potential strategies to reduce these. Organic arable crop rotations are generally diverse with the frequent use of legumes, intercropping and organic fertilisers. The soil organic matter content and the share of active organic matter, soil structure, microbial and faunal activity are higher in such diverse rotations, and the yields are lower, than in non-organic arable cropping systems based on less diverse systems and inorganic fertilisers. Soil mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is the potential for SMN accumulation and losses after crop termination, harvest or senescence. The risk of high N2O fluxes increases when large amounts of herbage or organic fertilisers with readily available nitrogen (N) and degradable carbon are incorporated into the soil or left on the surface. Freezing/thawing, drying/rewetting, compacted and/or wet soil and mechanical mixing of crop residues into the soil further enhance the risk of high N2O fluxes. N derived from soil organic matter (background emissions) does, however, seem to be the most important driver for N2O emission from organic arable crop rotations, and the correlation between yearly total N-input and N2O emissions is weak. Incorporation of N-rich plant residues or mechanical weeding followed by bare fallow conditions increases the risk of NO3 leaching. In contrast, strategic use of deep-rooted crops with long growing seasons or effective cover crops in the rotation reduces NO3 leaching risk. Enhanced recycling of herbage from green manures, crop residues and cover crops through biogas or composting may increase N efficiency and reduce N2O emissions and NO3 leaching. Mixtures of legumes (e.g. clover or vetch) and non-legumes (e.g. grasses or Brassica species) are as efficient cover crops for reducing NO3 leaching as monocultures of non-legume species. Continued regular use of cover crops has the potential to reduce NO3 leaching and enhance soil organic matter but may enhance N2O emissions. There is a need to optimise the use of crops and cover crops to enhance the synchrony of mineralisation with crop N uptake to enhance crop productivity, and this will concurrently reduce the long-term risks of NO3 leaching and N2O emissions.

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The emissions of nitrous oxide (N2O) and leaching of nitrate (NO3) have considerable negative impacts on climate and the environment. Although these environmental burdens are on average less per unit area in organic than in non-organic production, they are not smaller per unit of product. If organic farming is to maintain its goal of being an environmentally friendly production system, these emissions should be mitigated. We discuss the impact of possible triggers within organic arable farming practice for the risk of N2O emissions and NO3 leaching under European climatic conditions, and possible strategies to reduce these. Organic arable crop rotations can be characterised as diverse with frequent use of legumes, intercropping and organic fertilizers. The soil organic matter content and share of active organic matter, microbial and faunal activity are higher, soil structure better and yields lower, than in non-organic, arable crop rotations. Soil mineral nitrogen (SMN), N2O emissions and NO3 leaching are low under growing crops, but there is high potential for SMN accumulation and losses after crop termination or crop harvest. The risk for high N2O fluxes is increased when large amounts of herbage or organic fertilizers with readily available nitrogen (N) and carbon are incorporated into the soil or left on the surface. Freezing/thawing, drying/rewetting, compacted and/or wet soil and mixing with rotary harrow further enhance the risk for high N2O fluxes. These complex soil N dynamics mask the correlation between total N-input and N2O emissions from organic arable crop rotations. Incorporation of N rich plant residues or mechanical weeding followed by bare fallow increases the risk of nitrate leaching. In contrast, strategic use of deep-rooted crops with long growing seasons in the rotation reduces nitrate leaching risk. Reduced tillage can reduce N leaching if yields are maintained. Targeted treatment and use of herbage from green manures, crop residues and catch crops will increase N efficiency and reduce N2O emissions and NO3 leaching. Continued regular use of catch crops has the potential to reduce NO3 leaching but may enhance N2O emissions. A mixture of legumes and non-legumes (for instance grasses or cereals) are as efficient a catch crop as monocultures of non-legume species.

The contribution of catch crops to the ecological intensification of organic arable systems was investigated using data of a 12-year field experiment carried out at three sites in Denmark. This study focused on the yields of spring oats and spring barley in systems with and without manure in two different cropping systems that differed in the proportion of legume-based catch crops (O2 lower and O4 higher) and in the rotation composition (grass-clover green manure in O2 and pulse crops in O4). Three consecutive four-year crop rotations were established at three locations representative of the different soil types (loamy sand, sandy loam and coarse sand) and climatic conditions. Crop management and soil operations were performed following common practices in organic farming. Measurements of dry matter (DM) and nitrogen (N) content of grain cereals at harvest, aboveground biomass in catch crops and green manure crops in autumn and of the green manure crop at the first cutting were performed. The effect of catch crops on grain yield varied with cereal and catch crop species, soil and rotation type, and the application of N in manure. Higher yield increases from previous catch crops were obtained for spring oat than for spring barley with mean estimates of the apparent N recovery efficiency of 69% and 46%, respectively. However, lower autumn N in undersown crops with higher cash crop yields was also observed. For spring oats mean grain yield benefits of including catch crops varied from 0.2 to 2.4 Mg DM ha-1 31 depending on location, manure use and course of the rotation. In spring barley mean grain yield benefits from catch crops varied from 0.1 an 1.5 Mg DM ha-132 . There was a tendency for the effect of catch crop on grain yield to increase over time. These results indicate that in Nordic climates catch crops can contribute to the ecological intensification of spring cereals, not only by reducing the nitrate leaching and increasing N retention, but also by improving yields. Management practices in relation to catch crops must be adapted to the specific soil and cropping systems.

The effects of nitrogen (N) availability related to fertilizer type, catch crop management, and rotation composition on cereal yield and grain N were investigated in four organic and one conventional cropping systems in Denmark using the FASSET model. The four-year rotation studied was: spring barley–(faba bean or grass-clover)– potato–winter wheat. Experiments were done at three locations representative of the different soil types and climatic conditions in Denmark. The three organic systems that included faba bean as the N fixing crop comprised a system with manure (stored pig slurry) and undersowing catch crops (OF+C+M), a system with manure but without undersowing catch crops (OF−C + M), and a system without manure and with catch crops (OF + C−M). A grass-clover green manure was used asNfixing crop in the other organic system with catch crops (OG+C+M). Cuttings of grass-clover were removed from the plots and an equivalent amount of total-N in pig slurry was applied to the cropping system. The conventional rotation included mineral fertilizer and catch crops (CF+C+F), although only non-legume catch crops were used. Measurements of cereal dry matter (DM) at harvest and of grain N contents were done in all plots. On average the FASSET model was able to predict the yield and grain N of cereals with a reasonable accuracy for the range of cropping systems and soil types studied, having a particularly good performance on winter wheat. Cereal yields were better on the more loamy soil. DM yield and grain N content were mainly influenced by the type and amount of fertilizer-N at all three locations. Although a catch crop benefit in terms of yield and grain N was observed in most of the cases, a limited N availability affected the cereal production in the four organic systems. Scenario analyses conducted with the FASSET model indicated the possibility of increasing N fertilization without significantly affecting N leaching if there is an adequate catch crop management. This would also improve yields of cereal production of organic farming in Denmark.

This work evaluates the effects of growing a green manure crop or a legume crop in winter wheat yield and on nitrate leaching, in an irrigated crop rotation. Results are also compared with a conventional cropping system. Simulations with the field version of the FASSET model (Berntsen et al., 2003) were done to evaluate the performance of the model to predict winter wheat dry matter yield. The simulated leaching from the different cropping systems was evaluated during the rotation period.