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when we lose nitrous oxides to the atmosphere okay it has that effect on the climate whether it's margin or not it's not the argument but the argument is really we have lost money.

💨 tl;dr

This webinar dives into nitrogen use efficiency in vineyards, led by Dr. Michael Treeby. It covers soil fertility, nitrogen sources, and practical strategies to enhance efficiency, emphasizing the importance of timing, cover crops, and understanding nitrogen dynamics for better grape production.

💡 Key Ideas

• The webinar addresses nitrogen use efficiency in vineyards, emphasizing its importance for grape production.
• Dr. Michael Treeby, an agricultural scientist, leads the discussion on soil fertility, nitrogen sources, and practical solutions for improving efficiency.
• Nitrogen availability in soil varies and is influenced by factors like cover cropping, organic matter, and nitrogen management practices.
• Vine roots primarily uptake nitrogen in nitrate form, but effective management is crucial during key growth stages, especially in Spring.
• Nitrogen drawdown and the breakdown rates of cover crops significantly affect nitrogen availability for vines.
• Nitrous oxides and ammonia losses represent pollution and economic concerns, highlighting the need for better nitrogen management.
• Fertilizer placement and timing should align with vine phenology to optimize nutrient uptake and minimize waste.
• Soil management techniques like composted chicken manure and straw mulch can improve nitrogen delivery and soil health.
• There's a growing interest in using nitrification inhibitors and exploring organic versus synthetic fertilizers for better efficiency.
• Overall, understanding and managing nitrogen dynamics is essential for sustainable vineyard practices and grape quality.

🎓 Lessons Learnt

• Improve Nitrogen Use Efficiency: Implement practical solutions to manage nitrogen effectively in vineyards, recognizing that it’s not an exact science.

• Understand Fertilizer Types: Knowing the differences between synthetic and organic fertilizers is crucial for effective nitrogen management.

• Timing is Key: Proper timing of nitrogen application aligns with the vine's growth stages, especially critical periods for nitrogen uptake.

• Manage Soil Nitrogen: Be aware of soil nitrogen variability, leaching, and the long-term effects of past practices on future vine growth.

• Utilize Cover Crops Wisely: Cover crops can provide organic nitrogen but may not sync with vine needs; their breakdown rates vary significantly.

• Monitor Nitrate Levels: Nitrate levels can indicate fertilization effectiveness, but total nitrogen content is also essential for vine health.

• Balance Fertilization: Aim for balanced nutrient inputs to avoid over-fertilization, which can lead to wasted resources and poor crop yield.

• Incorporate Organic Matter: Large amounts of organic materials can positively impact soil health, but their application must be well-planned.

• Be Cautious with Irrigation and Nitrogen: Avoid nitrogen applications during waterlogged conditions to prevent losses and consider quick-growing cover crops to improve soil conditions.

• Engage in Continuous Learning: Stay informed by engaging with experts and participating in educational webinars to enhance nitrogen management practices.

🌚 Conclusion

To boost vineyard sustainability and grape quality, it's crucial to manage nitrogen effectively. This involves knowing your fertilizers, timing applications with vine growth, and continuously learning about best practices in nitrogen management.

In-Depth

All Key Ideas

Webinar on Nitrogen Use Efficiency in Vineyards

• The webinar focuses on nitrogen use efficiency in vineyards.
• Acknowledgment of traditional custodians of the land and their connections to the community.
• Dr. Michael Treeby, an agricultural scientist with extensive research experience, will present on this topic.
• Discussion will include the needs versus fertility in soil, synthetic versus organic fertilizers, and the fate of nitrogen in soils.
• The presentation aims to suggest practical solutions for improving nitrogen use efficiency in vineyards.
• The importance of understanding the nitrogen uptake by grapevines and its implications on grape production.
• Noting that out of every ton of grapes, a significant amount of carbon and nitrogen is removed.

Nitrogen and Soil Nutrients

• The mining of minerals in northwest Victoria and southwest New South Wales led to quick yield declines due to the depletion of soil nutrients like NPK and calcium.
• Unlike other nutrients, nitrogen is more abundant in the environment, which is why its situation isn't as dire.
• Dinitrogen gas from the atmosphere can be fixed into organic nitrogen through processes like leguminous cover crops and free-living nitrogen bacteria.
• The Haber-Bosch process fixes nitrogen gas into urea and ammonium fertilizers, but it requires significant energy and is contentious due to fossil fuel consumption.
• There are various nitrogen-containing fertilizers, including those derived from natural sources and those produced artificially.
• Nitrate in the soil can be lost through leaching and denitrification, contributing to greenhouse gas emissions.
• Ammonium can be lost as gas through volatilization, which is avoidable but can occur.
• Organic nitrogen is supplemented via fixation and organic amendments like plant residues and animal waste.
• Foliar sprays are another method of nitrogen supplementation, though evidence of their effectiveness is not solid.

Nitrogen Management in Vineyards

• Nitrous oxides (Nox) are powerful greenhouse gases contributing to climate change, though viticulture's overall contribution in Australia is relatively small.
• Loss of nitrous oxides and ammonia represents economic loss and pollution issues, including groundwater contamination.
• Vine roots primarily take up nitrate as the main form of nitrogen, with variability in soil organic matter and nitrogen levels.
• Coefficient of variation in soil nitrogen levels is high, indicating significant variability in nitrogen content across small distances.
• Rough estimates suggest that around 6.5 tons of nitrogen per hectare down to a meter depth exists in the soil, raising concerns about nitrogen management in vineyards.

Nitrogen Management in Vineyards

• The soil is organic and contains nitrogen, with local estimates suggesting it produces 0.4 to 0.9% of total nitrogen per year, varying between 26 and 60 kg per hectare.
• The nitrogen availability from the soil may not coincide with the needs of the vines.
• Cover cropping has been practiced since the mid-20s to produce organic nitrogen for vines, but the effectiveness can vary.
• Different cover crop types have varying carbon-to-nitrogen (C:N) ratios, affecting their breakdown speed; higher ratios mean slower breakdown.
• Organic matter decomposition rates are influenced by factors like wetting and drying events, cultivation, and cover crop type.
• The breakdown of cover crop materials is crucial for supplying nitrogen to vines when they need it, but coordinating this timing is challenging.

Nitrogen Management in Vineyards

• There are different types of cover crops that break down at varying speeds, impacting nitrogen availability.
• Nitrogen drawdown occurs when certain plants, like oats, extract nitrogen from the soil, affecting vine growth.
• Manipulating nitrogen supply is crucial for key vine development stages, such as inflorescence initiation, shoot growth, and dormancy.
• The processes in vineyards are multi-seasonal; actions from previous seasons influence current and future growth.
• Major nitrogen uptake and mobilization occur in specific periods, notably in Spring and early Autumn.

Nitrogen Management in Vineyards

• Uptake of nitrogen in vineyards kicks off in late spring, coinciding with bud initiation, which affects bud fertility.
• Low bud fertility due to nitrogen limitation cannot be remedied once the season progresses.
• Nitrogen storage occurs in the vine's permanent parts (trunk, cordons, canes, roots) after crop harvest, to be mobilized in the following spring.
• About half of the nitrogen taken up during summer ends up in the grapes, while the rest is in shoots and wood.
• Previous seasons' nitrogen management impacts subsequent growth and nitrogen availability in vines.
• A study showed that vines supplied with 100 kg of nitrogen had better growth and nitrogen content in fruit compared to those with zero nitrogen.
• Vines that received no nitrogen still retained about 100 units in their perennial parts, but had lower crop yields.

Nitrogen and Vine Growth

• Very small amounts of nitrogen in the outer third of the trunk are significant for vine growth and mobilization.
• The relationship between nitrogen application and vine nutrient status follows a response curve, where minor deficiencies lead to major effects, but excess does not improve growth.
• Adequate nitrogen levels are crucial, with specific ranges (0.8-1.1) identified for optimal vine health.
• Nitrate levels in vines and petioles are a small percentage of total nitrogen, with total organic nitrogen being essential for metabolism and growth.
• Nitrate is essentially useless unless converted to ammonium form, indicating effective fertilization systems are needed before flowering.

Nitrogen Management Insights

• Percent N is a good measure for assessing nitrogen efficiency in fertigation programs.
• High nitrate levels (around 2500) indicate potential issues with nitrogen conversion due to missing co-factors like molybdenum.
• Nitrate is an indicator of fertigation efficiency and internal physiological problems in vines.
• Internode length can be used to assess nitrogen management and vine vigor; shorter internodes may indicate nitrogen deficiency.
• Excessive watering can lead to a feedback loop where more nitrogen is applied, impacting vine growth negatively.
• Proper nitrogen fertilizer placement is crucial for assessing vine nutrition.

Nitrogen Management Practices

• Placing suitable amounts of fertilizer in the root zone is crucial for effective nitrogen use.
• Avoiding over-supplying water beyond the readily available water level is essential to prevent nutrient loss.
• Nitrogen application should align with vine phenology, specifically when roots are actively seeking nutrients.
• Water logging conditions increase the production of nitrous oxides, which represent economic loss.
• The composition of cover crop residues affects nitrogen availability based on the C:N ratio.
• Incorporating organic nitrogen reduces volatile compound loss and associated odors.
• Nitrification inhibitors are becoming more common in viticulture, though their use is less experienced compared to other production systems.

Fertilizer and Vineyard Management Insights

• Philosophical hurdle with using urea or ammonium fertilizers may decrease as renewable energy becomes more available and affordable.
• Matching supply with demand is key in vineyard management, particularly concerning vine phenology, vigor, and nutrient status.
• There’s a distinction between organic and synthetic fertilizers, with some organic producers favoring organic methods.
• Micro dosing fertigation and intra root zone placement are important for effective nutrient delivery, focusing on where roots extract most moisture.
• Weather predictions are becoming more reliable, which can aid in management decisions for avoiding leaching and water logging.
• The amount of carbon in soils may be overstated; actual levels of organic matter are quite low, which complicates discussions on carbon farming.

Soil and Vine Carbon Management

• Our soils have lower organic matter compared to other regions, with only 66 tons of CO2 equivalence in organic carbon, which is minimal.
• The amount of carbon in a vine is significantly less, with about 24 tons of CO2 equivalents per hectare in established vineyards.
• Using straw mulch under vines can suppress evaporation and summer weeds but involves a nitrogen drawdown.
• The benefits of nitrogen from straw mulch or between rows depend on specific goals, and the quantity of material needed for impact is substantial.
• Nitrate uptake in vines is converted into amino n, which is a major component of total nitrogen, but does not remain in the roots from the previous season.

Nitrogen Management in Vineyards

• If nitrate levels are low, it doesn't necessarily mean the vines are nitrogen deficient; it could indicate that the fertilizer program hasn't started or is inadequate.
• Assessing the vine's nitrogen needs should combine vigor with nitrogen analysis results.
• In waterlogged conditions, it's advised to hold off on nitrogen applications as it may be lost quickly.
• Sowing quick-growing cover crops, like oats, can help manage water levels before applying nitrogen fertilizers.
• Leaf greenness can indicate the effectiveness of foliar fertilizer applications in vineyards.
• During heat events, ensuring vines are healthy is crucial, as they experience oxidative stress rather than evaporative demand.

Agricultural Practices and Soil Management

• There is a certain amount of cooling achieved by evaporating water through plant stomata, and maintaining soil at field capacity aids this process.
• Microclimate manipulation, such as using overhead irrigation to cool vineyards, has been effective in grape production.
• Composted chicken manure has slow nitrogen movement to the root zone and is more effective when incorporated into the soil.
• Calcium nitrate is comparable to urea in efficiency, but it helps mitigate long-term soil acidification compared to other nitrogen sources.
• There is uncertainty about the benefits of foliar applications of nitrogen with fulvic acid, lacking concrete data to support claims.

Vineyard Event Highlights

• Many vineyards are visited in McLaren Vale, Barossa, Riverland, and Adelaide Hills.
• Experts in the field share practices, techniques, and tools in action in the vineyard.
• Registration for the event is limited, with a QR code provided for quick sign-up.
• Interaction with the audience is encouraged and appreciated.

All Lessons Learnt

Nitrogen Management in Vineyards

• Nitrogen use efficiency can be improved through practical solutions.
• Fertilizer management is not an exact science.
• Understanding the differences between synthetic and organic fertilizers is crucial.
• Recognize the fate of nitrogen in soils.
• Awareness of nutrient removal is key.

Lessons on Nitrogen Management

• Replace depleted nutrients in soil.
• Be aware of nitrogen sources and their processes.
• Avoid unnecessary nitrogen loss.
• Consider organic amendments for nitrogen.
• Evaluate the effectiveness of foliar sprays.

Nitrogen Management Strategies

• Minimize Nitrous Oxide Loss
• Manage Nitrogen Leaching
• Understand Soil Nitrogen Variability
• Consider Nitrogen Budgeting

Cover Cropping and Vine Needs

• Cover cropping doesn’t always sync with vine needs. While cover crops are used to provide organic nitrogen for vines, their breakdown may not coincide with the timing of vine nitrogen requirements.
• Different cover crops break down at varying rates. The C:N ratio indicates that materials with higher ratios take longer to decompose, affecting how quickly they can supply nutrients to vines; for example, grapevine material breaks down very slowly compared to fiber beans, which break down quickly.
• Organic matter depletion is influenced by environmental factors. Hot summers and wetting/drying cycles can significantly impact the organic matter levels in the soil, suggesting that management practices need to account for these conditions.

Nitrogen Management in Vine Growth

• Manipulate nitrogen supply to coincide with growth stages
• Long-term impact of past practices
• Critical periods for nitrogen uptake

Nitrogen Management in Vines

• Timing of Nitrogen Uptake: Nitrogen uptake in vines kicks off in late spring, around mid-November to October, which is critical for bud fertility. Proper timing is essential to ensure healthy fruit development.
• Impact of Nutrition on Bud Fertility: Low nitrogen levels can limit bud fertility, and once the season progresses, it's too late to correct this. Ensuring adequate nutrition early is key to producing a good crop.
• Storage of Nitrogen: After harvest, leaves export nitrogen into the permanent parts of the vine, which gets mobilized in the following spring. This highlights the importance of managing nitrogen throughout the season for future growth.
• Seasonal Effects on Growth: Actions taken in one season can significantly affect the following season's growth and nitrogen levels in the fruit. Consistency in nitrogen application helps maintain vine health across years.
• Nutrient Application Strategy: A nitrogen application of around 100 kg/ha can have a substantial impact, but over-fertilization should be avoided in wine grape production. Aim for balanced inputs to keep the cycle healthy.
• Long-term Nitrogen Retention: Vines that receive no nitrogen still retain a significant amount (around 100 units) in their perennial parts, but this leads to poor crop yield. Regular fertilization is necessary for optimal performance.

Fertilization Guidelines

• Fertilization Timing Matters: What you did last season affects the current season's vine performance, so proper timing in fertilization is crucial for optimal vine growth.
• Focus on Outer Trunk Nitrogen: Only the outer third of the trunk mobilizes nitrogen effectively, indicating that even small amounts can be significant for vine health.
• Target Marginal Nutrient Levels: Aim to maintain nutrient levels at marginal or early adequate ranges to avoid wasting resources on excess fertilization that yields no benefit.
• Nitrate Levels Are Not Everything: Having adequate total nitrogen doesn't always correlate with high nitrate levels; low nitrate can still indicate sufficient nutrition if total nitrogen is adequate.
• Use Nitrate as an Indicator: Nitrate levels can be a useful indicator to confirm that your fertilization is working, but it shouldn't be the sole focus.

Fertigation and Vine Management Tips

• Monitor nitrate levels for fertigation efficiency
• Watch for molybdenum deficiency
• Assess vine vigor using internode length
• Balance water and nitrogen supply
• Simplify assessments with interpretive tables

Fertilization Best Practices

• Placing suitable amounts of fertilizer in the root zone
• Avoiding over-supplying water
• Timing fertilizer application
• Incorporating organic materials
• Using nitrification inhibitors

Fertilizer Application Strategies

• Matching Supply with Demand: It's crucial to align fertilizer application with the vine's phenology, vigor, and nutrient status to optimize efficiency.
• Micro Dosing Fertigation: Applying fertilizers in smaller, more targeted doses can improve nutrient uptake by placing it in the root zone where roots are most active.
• Soil Moisture Monitoring: Utilize soil moisture monitoring systems to determine the best spots for fertilizer application, as this increases the likelihood of nutrient absorption.
• Weather Predictions for Management: Incorporate reliable weather predictions into vineyard management decisions to avoid issues like leaching and waterlogging.
• Consider Carbon Levels in Soil: Be cautious about assumptions regarding soil carbon content; there’s generally less organic matter in soils than expected, which impacts carbon farming discussions.

Vine Management Considerations

• Use of straw mulch under vines vs. in rows: It's important to consider the goals when deciding where to apply straw mulch. Under the vines can suppress evaporation and summer weeds, while between rows keeps the soil cooler for root exploration.
• Impact of organic material: To make a significant impact with organic material, a large amount is often needed. Its availability and the method of application (like using a side throwing slasher) can affect effectiveness.
• Understanding nitrogen uptake: When vines take up nitrate, it’s crucial to know that it doesn’t just sit; it gets converted in the roots or leaves to amino nitrogen, which is essential for growth.

Nitrogen Management Practices

• Start fertilization program early: If nitrate levels are low, it could mean the fertilizer program hasn't started or is inadequate, but it doesn't necessarily indicate nitrogen deficiency in the vines.
• Use nitrogen assessment tools: Assess the nitrogen needs of the vine based on vigor and nitrogen analysis results, as it’s a practical and easy tool to use.
• Be cautious with nitrogen applications in waterlogged conditions: In waterlogged conditions, it’s better to hold off on nitrogen applications, as they are likely to be lost quickly.
• Consider quick-growing cover crops: Planting quick germinating crops like oats can help reduce waterlogged conditions before applying nitrogen.
• Avoid unnecessary nitrogen fertilization for cover crops: Don't apply nitrogen fertilizer to waterlogged cover crops, as it may lead to wasted resources.
• Evaluate foliar fertilizer application: Investigate the use of foliar fertilizer for cover crops, but monitor leaf greenness to assess effectiveness.
• Be cautious with fertilization rates: Just because a little nitrogen is beneficial doesn’t mean a lot will be better; stick to recommended rates for optimal production.

Irrigation and Soil Management Techniques

• Ensure soil is at field capacity: Before cooling techniques are applied, maintaining the soil at field capacity is crucial for effective irrigation and cooling.
• Utilize evaporation for cooling: Keeping the vineyard floor wet can cause evaporation, which helps cool the vineyard, especially during heat events.
• Incorporate chicken manure locally: To enhance nitrogen uptake, it's more efficient to incorporate composted chicken manure directly into the soil rather than applying it on the surface.
• Monitor long-term soil acidification: Using calcium nitrate can mitigate soil acidification compared to urea, but it's important to be aware that soil acidification is a long-term issue that future generations will need to manage.
• Seek data on fulvic acid with foliar nitrogen: While there are claims about the benefits of fulvic acid in foliar applications of nitrogen, it's essential to look for scientific data to support these claims before applying.

Lessons for Learning

• Engage with experts in the field.
• Participate in webinars for continued learning.