Ambitious environmental and economic goals for the future of agriculture are unequally achieved by innovative cropping systems

International audienceAgriculture has to face huge challenges in the decades ahead. Four innovative cropping systems were assessed ina “cropping system experiment” in the Ile-de-France region (France) from 2009 to 2014. Three were designed tomeet ambitious goals: the total elimination of pesticides (No-Pest), reducing fossil energy consumption by 50%(L-EN), or decreasing greenhouse gas (GHG) emissions by 50% (L-GHG). They were also required to satisfy awide range of environmental criteria and to maximize yields whilst respecting the major constraint on the systemand the environmental targets set. A fourth system (PHEP), in which the environmental and yield targets wereachieved with no major constraint, was also assessed. After completion of the first full crop sequence for theseinnovative systems, the results obtained indicated that it was possible to design and implement innovativesystems achieving multiple goals. In our field trial conditions, the pesticide and energy constraints were almostsatisfied, whereas the GHG target was missed by a considerable margin. All four innovative systems satisfiedenvironmental criteria in terms of N management, pesticide use, energy consumption and crop diversity.However, herbicide treatment frequency index (TFIH) was higher than expected in the two systems with no-plowpractices, L-EN and L-GHG. In the pesticide-free system, soil organic matter content was lower than expected,due to frequent plowing (every 2 years) and low residue levels as a result of the lower yields obtained. Yieldswere lower for the L-EN system than for the reference system, and yield was variable in the L-GHG system. Theseinnovative systems had better environmental performances than the systems currently used in the Ile-de-Franceregion, with no decrease in gross margins

Temporal dynamics of earthworm-related macroporosity in tilled and non-tilled cropping systems

Tillage influences first soil structure and then soil organisms such as earthworms, which are highly involved in the creation of soil macroporosity. This study assessed the temporal dynamics of earthworm-related macroporosity in two ploughed and one unploughed cropping systems. Three sampling dates were chosen: one month before ploughing, and one and five months after the event. Earthworm communities, able to rebuild the macroporosity, were sampled one and five months after ploughing. Before ploughing, the burrow continuity, i.e., the number of burrows with a vertical length greater than 5 cm, was not significantly different in the three systems. It was stable between the three sampling dates in the unploughed system but it decreased by 65% and 46% after ploughing (i.e., in two months) in the organic and the conventional systems, respectively. Five months after ploughing, the burrow continuity remained between two and four times lower than in the unploughed living mulch cropping system. Earthworm biomass was higher and burrow system characteristics (i.e. burrow volume and continuity) were more stable over time in the non-tilled with a living mulch cropping system than in the tilled systems. Earthworm-produced macroporosity was thus substantially decreased after ploughing in conventional and organic systems and had still not totally recovered 5 months later. This can lead to large functional consequences on soil structure and thus on air and water fluxes in the soil

Can alternative cropping systems mitigate nitrogen losses? Results from a 17-yr experiment in Northern France

CT3 ; EnjS4 ; Département EACan alternative cropping systems mitigate nitrogen losses? Results from a 17-yr experiment in Northern France. European Society of Agronomy 14 congres

Contamination of rapeseed harvest by volunteers of other varieties : a study of intergenotypic competition

International audienc

Право и демократия, № 17

Alternative cropping systems such as conservation agriculture and organic farming are expected to decrease negative impacts of conventional systems through sequestration of organic carbon in soil and mitigation of greenhouse gas emissions. We studied soil organic carbon (SOC) dynamics in the long-term (16 years) field experiment “La Cage” (France) which compares four arable cropping systems, free from manure application, under conventional (CON), low input (LI), conservation agriculture (CA) and organic (ORG) management. Bulk densities and SOC concentrations were measured at different dates between 1998 and 2014. SOC stocks were calculated at equivalent soil mass taking into account bulk density variations and SOC redistribution across the different soil layers. We analyzed the evolution of SOC stocks and compared it with outputs of the simulation model AMG. The rate of change in SOC stocks in the old ploughed layer (ca. 0–30 cm) during the 16 years was 0.08, 0.02, 0.63 and 0.28 t ha−1 yr−1 in the CON, LI, CA and ORG systems respectively and significantly differed from 0 in the CA and ORG treatments. The AMG model satisfactorily reproduced the observed evolution of SOC stocks in the old ploughed layer in all treatments. A Bayesian optimization procedure was used to assess the mean and the distribution of the most uncertain parameters: the SOC mineralization rate and the C inputs derived from belowground biomass of cover crops which were fescue (Festuca rubra) and alfalfa (Medicago sativa). The model thus parameterized was able to predict SOC evolution in each block and soil layer (0–10, 10–20 and 20–30 cm). There was no significant difference in SOC mineralization rates between all cropping systems including CA under no-till. In particular, the increased SOC storage in CA was explained by higher carbon inputs compared to the other cropping systems (+1.72 t C ha−1 yr−1 on average). The CA and ORG systems were less productive than the CON and LI systems but the smaller C inputs derived from cash crop residues were compensated by the extra inputs from additional crops (fescue and alfalfa) specifically grown in CA and ORG, resulting in a positive carbon storage in soil. We conclude that alternative arable systems have potential to sequester organic carbon in temperate climate conditions, through higher carbon input rather than by the effect of reduced soil tillage

Can alternative cropping systems mitigate nitrogen losses and improve ghg balance? Results from a 19-yr experiment in northern France

International audienceAlternative cropping systems are promoted to reduce nitrogen (N) losses in the environment and mitigate greenhouse gas (GHG) emissions. However, these supposed benefits are not fully known, rarely studied together and on the long-term. Here, we studied the N inputs, N exports, soil organic N (SON) storage, N leaching, gaseous N emissions and GHG balance in a 19-yr field experiment comparing four arable cropping systems without manure fertilization, under conventional (CON), low-input (LI), conservation agriculture (CA) and organic (ORG) managements. The N surplus, i.e. the difference between total N inputs and exports, was lowest in LI (43 kg ha(-1) yr(-1)), intermediary for CON and ORG with 63 kg ha(-1) yr(-1) and highest in CA (163 kg ha(-1) yr(-1)). CA and ORG received high amounts of N derived from biological fixation from alfalfa. The annual SON storage rates markedly differed between CA (55 kg ha(-1) yr(-1)) and both CON and LI (13 and 6 kg ha(-1) yr(-1)), with intermediary value in ORG (30 kg ha(-1) yr(-1)). N leaching, calculated using soil mineral N measurements, reached an average of 21 kg ha(-1) yr(-1) and did not significantly differ between treatments, The gaseous N emissions (volatilization + denitrification), calculated as the difference between N surplus, SON storage and N leaching, ranged from 12 kg ha(-1) yr(-1) in ORG to 83 kg ha(-1) yr(-1) in CA. N2O emissions were continuously monitored with automatic chambers during 40 months. They varied from 1.20 kg ha(-1) yr(-1) in LI to 4.09 kg ha(-1) yr(-1) in CA system and were highly correlated with calculated gaseous N emissions. The GHG balance, calculated using SOC and N2O measurements, varied widely between systems: it was highest in CON and LI, with 2198 and 1763 kg CO2eq ha(-1) yr(-1) respectively. In CA, the GHG balance was much more favourable (306 kg CO2eq ha(-1) yr(-1)), despite important N2O losses which partly offset the benefit of SOC storage. ORG was the system with the smallest GHG balance (-65 kg CO2eq ha(-1) yr(-1)), acting as a CO2 sink in the long-term. Similar trends were observed when GHG was expressed per unit of N input or N exported. The N surplus alone was not a good indicator of the N fate in the four agricultural systems. Complementary predictors of N losses and GHG balance are required to obtain a true overview of the C and N environmental impacts of cropping systems. On an operational point of view, these results should lead to investigate the variability of the GHG emissions within each cropping system

Effect of weather conditions on N2O emission patterns during winter cereal cultivation in two different climatic regions

International audienc

Field testing of IPM-based cropping systems: a diversity of experimental approaches in Europe

International audienceIntegrated Pest Management (IPM) emphasizes physical and biological regulation strategies to control pests while reducing the reliance on pesticides. It is often based on combinations of control measures, because each available alternative measure might have a moderate efficiency. Field experiments are required to analyse the interactions between control measures, and to evaluate the sustainability of IPM-based cropping systems (CS). A network of European agronomists managing field experiments at the CS level was set recently, aiming at sharing data and expertise to enhance our knowledge on IPM. Comparing methodologies highlighted a diversity of approaches in CS design and experimental layouts. This diversity is partly related with the research context and objectives. Some experiments intend to explore really innovative strategies and gain scientific knowledge about how such innovative CS behave, while others aim at providing quickly adoptable solutions for local farmers. In some research programs, the experiment is part of the CS design process, and tested CS are regularly revised, while in other cases CS are kept stable across years so as to be able to evaluate cumulative long term effects. The concept of CS itself is viewed differently across scientists, and this affects protocols: some consider each CS as a sequence of techniques, which has to be similar across repetitions, others define a CS as a set of decision-making rules that allows a flexibility in the actual sequences of techniques. The main difference among experiments differentiates factorial layouts from systemic approaches: factorial experiments make it possible to quantify the effects of each IPM factor, and to analyse the interactions, without particular attention for the consistency among components constituting each CS. On the contrary, system approach focuses on the overall evaluation of CS designed with a great attention paid to their consistency, hence maximizing the chance to meet the system objectives (in the case of IPM, to use little amount of pesticide while maintaining the CS sustainability). Such field experiments are costly, so preliminary reflections defining the experimental strategy have a critical importance. Networking at the European level may constitute a useful exchange platform with potential scientific added value

Diversity of methodologies to experiment Integrated Pest Management in arable cropping systems: Analysis and reflections based on a European network

Diversity of methodologies to experiment Integrated PestManagement in arable cropping systems: Analysis and reflectionsbased on a European network

ECoPESt - Evaluation et comparaison des performances environnementales de systèmes de culture innovants conçus pour réduire l’usage des pesticides : lien entre pratiques, pressions et impacts. Rapport final, 130 pp.

Rapport final, 130 p