Crop-Livestock Farming Systems Assessment in Europe

In average, farm gate balance nitrogen excess is reduced (-14%), while farm gate efficiency is increased (+22%). This is mainly due to a higher reduction of N inputs (-36 Kg N/Ha) than outputs (-21 Kg N/Ha).

The decrease in inputs concerned all types of inputs: decrease of nitrogen fertilizer inputs (-28%), concentrate feed (-11%), plants inputs (-8%), nitrogen fixation. Organic load in farms has slightly decreased (-6%), mainly due to less livestock reduction (-9% LSU cattle), whereas manure is more often kept on farm (52% reduction of exported organic fertilizer).

The decrease in farm outputs concern mainly plants outputs (-32%) whereas animal's outputs only decline of -6%. In 8 farms over 9, cattle efficiency shows a slight improvement as animals' outputs are increasing with a stable level of N intake per LSU.

On average, this illustrate the fact that farm strategy changed. Livestock feed autonomy is improved in innovative systems with a stable primary production (-2% yield as t DM/ha) for a small decline of stocking rate (1.48 LSU/ha AA in baseline, 1.33 in innovative farms). This generates a more important reduction in concentrate feed and plant product inputs (-15 Kg N/Ha) than the reduction in plant and animals outputs (-10 Kg N/Ha).

Those changes in N fluxes at farm gate improve the environmental impact of innovative farms. N leaching risk decreases of 17% per hectare of agricultural area (AA). The reduction of leaching is still of -8% per unit of N produced by the farm in product (N in milk, meat, plants outputs, taking into account stock variation and animals bought).

This estimation of leaching risk is based on fertilizer, crops residues and organic fertilizer inputs on AA. But in the baseline situation, there is also more animal feed imported on farm. Those inputs generate nitrate leaching in the cropping farm where they are produced, which are not taken into account here. So we can conclude that the gain of nitrate leaching risks per unit of product estimated here is under the real gain.

Damaging N air fluxes (NH3, N20, and NO) aggregated in terms of Kg N lost per year/ ha AA. The innovative situations improve air losses of -16% compared with initial baseline. The reduction of N air losses per unit of N in product is smaller (only -2%). But here again, additional losses should be included by considering NH3 and N20 losses due to crop residues and mineral fertilizer use in cropping area producing feed imported on the farm. So the total gain by unit of product is higher if considering the losses at the territory scale.

P fluxes on farms are moderate on average and phosphorus farm gate balance excess is low in both situations (around 5 kg P/HA AA) with high efficiency.

Carbon captured by crops on farm by photosynthesis is the main carbon flux in mass and is slightly increased (+5%) in innovative situations, whereas physical exchanges of C in goods entering or living the farm is rather stable (-1% farm gate C).

The part of this carbon flow that is lost as methane per hectare of AA is decreased by 17% in innovative situation while livestock stocking only decreases of 9%. There is less methane emitted per unit of animal production, which shows an improvement in innovative situations.

Direct and indirect energy use are decreasing and production of renewable energy (biomass, photovoltaic, and biogas) is introduced in farm. These aspects show that the average energetic situation is improved in innovative farms.

This results in a diminution of farm global warming potential of 17% per hectare (direct farm emissions only). Nevertheless, as permanent grassland is also decreasing in farms AA, the ability for farming system to store carbon in soil is also decreased: 30% less.

The following table sums up the main results of the analysis of CNP fluxes. In green are the cases where the implemented option has led to an improvement of the environmental performance and in yellow the cases where there is a degradation (in grey, no significative effect). We can see that it is not possible to guarantee an improvement, but the general trend is towards improvement, "green cells" being more numerous. This conclusion is confirmed by the second table where are shown the numbers of farms where the innovation leads to an improvement, a degradation or is neutral. So, we can say that implemented innovations are generally positive for the water quality and the global warming potential but are not efficient for air quality.