Sunflower fields in Australia are predominantly cultivated in key locations such as Northern New South Wales, Southern Queensland, and Central Queensland.
This blog solely focuses on how to maximise yields in your sunflower field with conversion tillage. To make the most of this guide, be sure to read to the conclusion.
Sunflower is primarily cultivated for its oil. The oil comprises around 15% saturated fatty acids and 85% unsaturated fatty acids. Within its unsaturated fatty acid composition, it consists of approximately 14–43% oleic acid and 44–75% linoleic acid.
Conversation Tillage Practices: Perfect Fit for Sunflower Fields
It is essential for farmers to keep the seedbed uniform and the soil properties consistent, particularly in terms of having sufficient moisture. This is crucial if they want the fields to have consistent seed germination and plant growth.
The seeds require a soil temperature between 70°F and 75°F to successfully germinate. If germination and plant emergence are poor, it will impact the effectiveness of future farming practices.
Conservation tillage techniques offer effective means of maintaining moisture in sunflower fields. These methods help create a protective layer of crop residues on the soil surface by minimising soil disturbance. This layer acts as a natural barrier, reducing water evaporation from the soil and thus preserving soil moisture levels.
The 2006 Kelly Tillage System is responsible for handling sunflower residue. Equipped with sharp-edged K4 Discs at the machine’s front and blunt CL1 Discs at the rear, this model effectively transforms the residue into a mulch layer. This layer acts as insulation for the soil, guarding it against erosion.
Certainly, the soil insulation created by this disc harrow also contributes to retaining moisture. By converting crop residue into a mulch layer, the diamond harrow helps to form a protective barrier that reduces water evaporation from the soil. This retained moisture is crucial for nurturing sunflower growth.
Here are additional points that explain how practising conservation tillage can help you achieve maximum yields in your sunflower field:
Preserves Soil Structure
Shallow tillage involves working the soil at a relatively shallow depth, which helps to minimise disruption to the natural arrangement of soil particles. This is important because the way soil particles are organised, affects water infiltration, root penetration, and overall soil health. By not disturbing the soil structure too deeply, this tillage allows water movement, root growth, and nutrient availability.
Prevents Compaction and Crusting
Deep tillage can lead to soil compaction, where the soil particles are pressed closely together, reducing pore space and hindering water infiltration and root development.
Additionally, it can lead to soil crusting on the surface, which forms a hard layer that water struggles to penetrate and seedlings find difficult to emerge through.
Reduced tillage minimises the risk of these issues, as it disturbs the soil less and maintains better soil porosity, reducing the likelihood of compaction and crusting.
Improves Aeration
Shallow tillage can improve soil aeration, which is the presence of air in the soil. Sufficient soil aeration is crucial for the survival of beneficial soil microorganisms and root respiration. When soil is compacted or lacks sufficient pore spaces, air movement is restricted, leading to oxygen depletion in the root zone.
Shallow tillage helps to maintain these vital pore spaces, ensuring a healthier environment for roots and soil organisms.
Enhanced Water Movement
Soil needs to be able to efficiently absorb and transport water to plant roots. Deep tillage can disrupt soil structure and create pathways that encourage water movement away from the root zone, leading to waterlogging in lower areas.
Reduced tillage, on the other hand, maintains a more even distribution of soil particles and pores, allowing water to move more uniformly through the soil profile and reach plant roots where it’s needed.
Decreased Risk of Soil Borne Diseases
Some soil-borne diseases, like downy mildew, can thrive in environments where moisture is retained and air circulation is poor. Deep tillage can create conditions that encourage the growth and spread of such diseases by disrupting the balance of moisture and air in the soil.
Minimum tillage, by preserving soil structure and allowing better drainage and aeration, helps create an environment that is less conducive to the development of these diseases.
Promotes Nutrient Uptake
When soil structure is maintained and compaction is minimised, plant roots can grow more freely, accessing a larger volume of soil. This increased root exploration enables better uptake of nutrients and water, leading to healthier and more productive plants.
Additionally, the improved aeration and water movement resulting from minimum tillage support the efficient delivery of nutrients to roots, further contributing to increased crop yields.
Sunflower Production Field Selection
Field selection is crucial to get opimum sunflower yeild. Here’s how:
Avoid Herbicide Residues
Ensure that the chosen field has no lingering residues of herbicides, especially those that sunflowers are sensitive to, like sulfonylureas and picloram.
Crop Rotation
Select fields that have previously been sown with cereals or legume crops. This rotation helps manage disease and pest pressures.
Stubble Cover
Opt for fields with a sufficient amount of stubble cover. This helps prevent soil erosion, retains moisture, and provides support for sunflower growth.
Minimal BroadLeaf Weed
Prioritise fields with minimal presence of broadleaf weeds. Competing weeds can hinder sunflower growth and yield.
Consider Parthenium Weed
In Central Queensland, it’s advisable to select fields located away from areas heavily infested with parthenium weed. This precaution minimises the risk of encountering this problematic weed.
Crop Rotation Gap
Ensure that the chosen farm field hasn’t had another broadleaf crop sown in the last three years. This prevents the build-up of diseases and pests specific to broadleaf plants.
Sowing Time
Sunflowers indeed offer distinct advantages due to their ability to be sown in two different windows.
Early Spring Planting (Mid-August to End of October)
This early planting window allows for the sowing of a portion of the summer crop area before the main planting window for other crops like sorghum. This can be beneficial as it enables farmers to get a head start on the growing season and potentially maximise yields.
However, there are risks involved such as late frost and low soil temperatures during establishment, as well as the possibility of heat stress during flowering and seed fill. Additionally, crops sown in spring might require more water due to the hotter summer conditions and the extended growing season.
Late Summer Planting (November to End of January)
The late summer planting window offers the opportunity for double cropping after a winter cereal in favourable seasons. This means that after harvesting a winter cereal crop, sunflowers can be planted in the same field during this window.
This can be economically advantageous as it allows farmers to get two crops from the same field in a single year. However, there are risks associated with late planting, including exposure to extreme temperatures during establishment.
Planting after the end of January also increases the vulnerability to diseases like sclerotinia and powdery mildew. Additionally, late-planted crops may face the threat of frost damage and slower crop drying towards the end of the season.
Waterlogging
Below are the ways to prevent waterlogging in your sunflower fields:
Preventing WaterLogging during Sunflower Seed Germination and Early Growth
During the germination of sunflower seeds and the initial growth stages of the seedlings, it is crucial to avoid waterlogging. This is because young plants are particularly vulnerable to pathogens like Pythium and Rhizoctonia under conditions of excessive moisture and poor drainage.
This issue is especially common in heavy vertisols, particularly in low-lying or compacted areas within the field.
When seeds and seedlings are affected by waterlogging, they can decay and die, resulting in barren patches that provide an opportunity for weeds to flourish.
Meet The K4 The Future of Sustainable Weed Control
- Tough on Weeds
The sharp edge of the K4 disc uproots weeds from the ground, turning them over and exposing them on the surface to die.
- Soft on Soils
The K4 takes the weed-killing power of our CL2 Disc Chain and adapts it to a lighter, less aggressive unit.
Building Resilience
As sunflowers mature beyond their initial growth stages, they develop greater tolerance to short-term waterlogging. Temporary waterlogged conditions lasting up to 48 hours typically do not lead to plant death.
However, caution is needed during grain filling, as even temporary waterlogging can significantly impact yield.
Mitigation Strategies
- Implement effective drainage practices in water-prone areas.
- Monitor weather forecasts to anticipate and manage waterlogging risks.
- Provide well-draining soil or raised beds for vulnerable seedlings.
- Enhance soil aeration through appropriate tillage methods.
- Consider adjusting planting times based on weather patterns.
Nutrients for Crop
Following are the necessaey nutrients for your sunflower field:
Nitrogen
The correlation between initial soil nitrogen levels, soil moisture, and crop yields holds significant importance.
When developing a nitrogen fertilisation plan, it is crucial to aim for an achievable yield while taking into account factors such as soil analyses, the availability of water for plants at the time of sowing, the previous crop’s yield, and its protein content.
An optimal nitrogen fertilisation strategy seeks to strike a balance. Excessive nitrogen application can lead to an overgrowth of vegetation, potentially resulting in a decrease in oil content.
On the other hand, insufficient nitrogen supply can limit crop yields by adversely affecting the establishment of crops, causing uneven growth and maturation, and rendering the plants more susceptible to diseases and pests throughout the growing season.
Phosphorus
Phosphorus ranks as the second most common nutrient deficiency in sunflower cultivation, right after nitrogen. When levels of arbuscular mycorrhizal (AM) fungi are insufficient due to factors like extended fallow periods, and previous canola or rice crops, ensuring an adequate supply of phosphorus and zinc fertilisers becomes highly critical.
In cases of alkaline soils with restricted zinc availability, the application of foliar zinc can prove advantageous.
Potassium
In older soils, there might be a deficiency or excess of potassium in the topsoil. Potassium tends to stay relatively fixed in the soil, highlighting the significance of assessing potassium levels throughout the soil profile rather than focusing solely on the upper layer.
Sufficient potassium is crucial for sunflowers as it strengthens stem integrity and enhances the plant’s capacity to manage periods of drought.
Sulphur
Sufficient availability of sulphur is also necessary between the completion of floret formation and flowering. This is important to avoid the loss of florets and to support the growth of well-developed seeds.
When sunflowers experience a lack of sulphur during the seed-filling period, the outcome is kernels containing inadequate levels of crucial sulphur-containing amino acids.
Summing Up
In summary, implementing conservation tillage techniques in your sunflower field is a reliable strategy for boosting yields. This sustainable approach promotes soil health, moisture retention, and a thriving ecosystem, leading to enhanced sunflower growth and increased overall productivity.