Short Description of the technology

Agricultural nitrous oxide (N₂O) emissions are a major environmental concern due to their high global warming potential, being 298 times more potent than CO₂ over a 100-year period. Vineyards, particularly those that rely on synthetic fertilizers and intensive tillage, contribute significantly to N₂O emissions. This experiment focuses on optimizing and quantifying the impact of three organic farming practices in two commercial vineyards, aiming for a 20-25% reduction in N₂O emissions. The selected practices include the cultivation of winter legumes as green manure, the implementation of non-cultivation with mowing, and the utilization of wooden residues and grape marcs. The James Hutton Institute (JHI) will conduct greenhouse gas (GHG) analyses to assess the effectiveness of these strategies.

Innovative Features

• Organic Farming Strategies for N₂O Reduction

One of the primary strategies for reducing N₂O emissions is the cultivation of winter legumes as green manure. Leguminous plants such as Vicia faba fix atmospheric nitrogen (N₂) into the soil, reducing the need for synthetic fertilizers, which are a significant source of N₂O emissions. These legumes sown in the winter and incorporated into the soil at the stage of flowering the plants, enhancing soil fertility while minimizing nitrogen losses. The anticipated outcome includes lower synthetic nitrogen input, improved soil organic matter, and enhanced microbial activity, all contributing to a reduction in N₂O emissions.

The second strategy focuses on non-cultivation and mowing, which aims to minimize soil disturbance and its associated N₂O emissions. Traditional tillage aerates the soil, creating conditions that promote microbial nitrification and denitrification, key processes in N₂O production. By maintaining permanent grass cover and using periodic mowing instead of plowing, soil structure is preserved, and microbial activity is stabilized. This approach is expected to result in lower N₂O emissions due to reduced microbial nitrogen turnover and increased carbon sequestration in the soil.

The third strategy involves the use of wooden residues and grape marcs, both by-products of vineyard operations management cultivation techniques. These materials serve as a high-carbon organic amendment, which influences soil nitrogen cycling by increasing the carbon-to-nitrogen (C:N) ratio. The slow decomposition of these residues promotes microbial immobilization of nitrogen, reducing its availability for nitrification and subsequent N₂O emissions. The application of composted wooden residues and grape marcs as mulch will not only enhance soil organic carbon levels but also improve soil water retention and microbial biodiversity.

Type of Contribution

• Vine Physiological Response Evaluation

Following the implementation of these organic farming practices, physiological measurements were conducted to assess their effects on vine performance. Photosynthesis, leaf respiration, and transpiration rates were measured to evaluate how the modified soil management strategies influenced plant metabolic activity. These results provided insights into how reduced soil disturbance, improved nitrogen cycling from legumes, and increased organic matter from residues contributed to vine health and metabolic efficiency.

• Analysis of Grape Quality Parameters

To further understand the impact of these practices, multiple grape quality parameters were analyzed. These included sugar content, acidity, phenolic composition, and berry antioxidant capacity. The assessment aimed to determine whether the reduction in N₂O emissions and the associated improvements in soil conditions influenced fruit development and overall grape quality.

• Implications for Sustainable Viticulture

The data collected can help establish whether these sustainable practices not only mitigate environmental impacts but also maintain or enhance grape quality and production. By improving soil health and optimizing vine physiological responses, these organic approaches reinforce the viability of sustainable viticulture, supporting both environmental and economic goals in commercial vineyards.

• GHG Analysis Methodology by JHI

The James Hutton Institute (JHI) conducted a comprehensive GHG analysis to quantify the impact of these organic farming practices on N₂O emissions. Static chamber measurements used to capture N₂O fluxes periodically throughout the growing season. Soil nitrogen dynamics, including nitrate and ammonium concentrations, monitored to assess changes in nitrogen availability. Additionally, carbon sequestration assessments will be carried out to evaluate soil organic matter accumulation. Comparative emissions modeling will be employed to analyze the difference between conventional vineyard management and the implemented organic practices, using IPCC emission factors and field-specific data.

Benefits for farmers, the industry, and the environment

• Reduction of N₂O Emissions and Soil Sustainability

By integrating these three organic farming practices, the study aims to achieve a 20-25% reduction in N₂O emissions across both vineyards. The reduction in synthetic nitrogen inputs and the enhancement of soil organic matter will contribute to a more sustainable nutrient cycle. Improved soil structure and carbon sequestration will further enhance vineyard resilience to climate variability.

• Influence on Vine Physiology and Productivity

Beyond the environmental benefits, these practices also impact vine physiology and grape quality. Measurements of photosynthesis, respiration, and transpiration indicate that the improved soil conditions support vine metabolic efficiency, potentially leading to more resilient plants with optimized water and nutrient use.

• Enhancement of Grape Quality

Furthermore, the analysis of grape quality parameters, including sugar content, acidity, and phenolic composition, suggests that these sustainable practices can maintain or even enhance grape quality.

• Economic and Environmental Viability

By simultaneously reducing emissions and preserving productivity, these approaches offer a practical pathway toward more sustainable viticulture, balancing environmental responsibility with economic viability. These practices ensure long-term sustainability for vineyard operations while minimizing negative environmental impacts.