Soil Moisture Probe Site Servicing

Soil Moisture Probe Site Service

 

Servicing your soil moisture probe sites gives your telemetry the best chance at performing well – and is a service we offer! As seen below, these are common problems our technicians come across in the field; pugging, chewed cables, and blocked rain gauges. Whether you use your data to guide your decisions on farm or you simply rely on your data for auditing and compliance purposes, these issues won’t be helping your case.

Our soil moisture site service includes a rain gauge calibration, because over time being exposed to the elements, things can change. If you feel that your rain gauge data is out of line, we are more than happy to calibrate it for you. We also check over the quality of data your probe is creating to ensure that it is settled and as accurate as possible. Whilst on site, an assessment of the surroundings is taken to see whether moving the probe would be beneficial, that solar panels are facing north, no pugging has occurred, and that rain gauges aren’t blocked. An annual soil moisture report is then crafted up by one of the technicians for you to keep and reflect over for the coming months. Any further advice required will be also given.

EM Surveying – Knowledge is Power

An Electro-magnetic (EM) Survey is one of the key layers required on the precision farming journey. Precise location and understanding of soil types is a key piece of information in driving decisions around water use and nutrient placement. Not only can an EM Survey be used to reduce water inputs it can form the basis of other decisions related to plant health, production and nutrient uptake. 

An EM Survey measures two soil profiles, one measuring the variability in the top 0-50 cm of soil and the other looking at variability in the top 0-125cm of your soil profile. Following a survey customers receive a comprehensive report outlining the findings in each survey depth. Depending on the variability arising from the survey, different management zones can be created to suit the final application. These zoned maps can then be used as the basis for variable rate irrigation (VRI) variable rate fertiliser, variable rate seeding and much more. 

Figure 1. Top left is a shallow EM map and to the right of it a zoned map of that layer. Below is the same but for the deeper EM (0-125cm).

As well as collecting detailed soil information, and EM Survey also collected detailed topographic information. This data set in its own right is very useful and builds a deeper understanding of the role surface topographic changes play in water movement across the area. Coupled with the soil variability data itself this data can identify key areas for management changes to make a large difference to paddock, pasture, crop and nutrient management. 

Figure 2. Specialist precision ag software generates water movement models based on the topography data.

Another simple but effective use for EM Survey data is to use it for placing soil moisture probes based on soil variability and slope to find your optimum site within each management zone. These sites can also be used as ground-truthing sites for water-holding capacity. From these your EM map can then be converted into a water-holding capacity map

EM Surveying information can be used for a myriad of uses, not all of which we’ve covered in this article. As soil is the basis for farming the land we work with, it makes sense to ‘dig a bit deeper’ and start our precision ag journey with a deeper understanding of our soils. 

New to the Vantage portfolio is water-holding capacity assessments. These work alongide our EM Survey to aid in making more informed decisions. You can find out more about water-holding capacity assessments and what they add here. 

To understand how EM Surveying can be used in your business, reach out to the Vantage NZ team to learn more. 

My soil moisture sensor hasn’t responded as I expected? Why?

From time to time we get the query: “my soil moisture sensor hasn’t responded to recent irrigation events, there must be something wrong with the sensor”.

While it is easy and natural to blame the sensor, the reason is often found in the field. There are physical reasons why a sensor may not register an event and the problem could be caused by a combination of these.

Figure 1. An irrigation event causing a neutral change in soil moisture content.

Canopy interception

The crop’s canopy will intercept some of the rainfall and/or irrigation water. Obviously, this will vary greatly from crop to crop and throughout the growth stages. It stands to reason that a mature crop of maize will intercept more water than freshly grazed pasture.

Much of the intercepted water will evaporate, but while it is sitting on the leaf it will cool the leaf and reduce the plant’s evapotranspiration rates.

Some of the intercepted water will trickle down the stem and enter the soil at the plant base, but not in sufficient quantities to register at the first sensor depth.

This scenario will look like a neutral response on the soil moisture graph (Figure 1). The irrigation event has not caused a soil moisture increase, but it did satisfy the plant’s evapotranspiration demand, so there is no water use for the day.

Application depth –less than daily water use and/or less than 0-100mm deficit

This tends to be a problem under pivots and fixed sprinklers. Daily irrigation of 4-5mm may not be enough to result in a significant change in soil moisture content at the first sensor depth (100mm). Firstly, some of the water will be intercepted. Secondly, the application may be less than the deficit present above the first sensor site, the water will infiltrate into the soil but may be absorbed in the top 50mm of soil.  In this case the response to the irrigation event at the first sensor (100mm) will, at best be a “flattening” of the trace; soil moisture will remain at its current level.

Bypass-flow -dry soils and soil type

Bypass-flow occurs when water passes through the macro pores (or gaps between soil particles) and is not absorbed by the soil particles. Bypass-flow and soil type are linked; coarse texture soils have more macro pores, increasing the potential for bypass-flow.

Bypass-flow and soil moisture content are also linked. As a soil dries it can undergo slight structural changes which may result in increased macro-porosity. The effect of drying varies with soil type. A fine textured soil with higher clay content will tend to shrink; typically, at the surface of the soil resulting in opening of cracks in the soil. In coarser textured soils cracks will not develop, but individual aggregates will contract, increasing the soil’s macro-porosity.

Water passing through the macro pores, or cracks, may not be registered by the soil moisture sensor; firstly, because the slurry used when the sensor is installed will have fewer macro pores than the rest of the field; and secondly, because the water fails to ‘linger’ long enough to infiltrate and re-wet the dry slurry the sensor is installed in.

Lack of sensor response due to a dry soil profile is most common in crops where the readily available water is greatest, e.g. wheat or carrot seed.

It is less common in frequently irrigated crops where the readily available water is small, e.g. ryegrass pasture, vegetable seeds and peas.

Key management strategies

It is useful to think of the soil moisture sensor as any other tool on the farm; it needs to be maintained to work properly. The sensor responses will be more reliable if slurry is not allowed to dry out. Soil moisture sensor management strategies include:

Adjust application depth to overcome crop interception.

Adjust application depth to be greater than daily water use.

Adjust application depth to ensure irrigation water will replace the target deficit.

If the slurry has dried and sensor response is lost, this is resolved through long duration rainfall, rather than re-installation of sensors. Usually all sensors regain perfect contact with the soil over the winter months.

At Vantage NZ we are proud to supply you with high quality AquaCheck soil moisture sensors and neutron services and to back it up with a high standard of service and expertise. Give us a call to discuss your soil moisture monitoring requirements and get set up in good time for the 2021-22 season. 

Article written by: Jane Robb, Customer Support Specialist

Variable-rate approach to fodder crops

During crop establishment and the growing season soil variability is a key driver to crop performance. This is true for both arable and fodder crops.

Lighter soils have lower water-holding capacities, and they warm up faster in the spring, which promotes earlier plant growth. Heavier soils with higher water-holding capacity take a bit longer to ‘get out of bed’ in the spring because of their lower soil temperatures.

If you can map soil variability, it gives the ability to do variable-rate seeding. On some soil types and with some crops, this can be a great way to set the crop up in a timely fashion to maximise performance throughout the season.

Typically, lower seeding rates are used in areas with lighter soils and higher rates in areas with heavier soils.

Sometimes the rates might only vary by +/- 10 percent of the originally intended seeding rate. However, it still gives the crop a greater ability to grow well with less competition for water and nutrients, particularly in lighter soil areas.

To achieve variable rate seedling and the variable rate application of subsequent inputs, you need a solid base of information in order to make the right decisions. And, of course, you need the right technology to achieve it.

Depending on the nature of the farm and the crops it supports, the information that underpins variable rate farming can range from electro-magnetic (EM) soil surveying, to grid or zonal soil sampling, to drone or satellite imagery.

EM surveying is used to map soil variability and thus, productivity potential. EM mapping has to be done when soils are at field capacity, so it is typically done over autumn, winter and spring.

The cost of EM surveying starts at $70/ha. While it is an expense, an EM survey provides information that you can use for many years. It underpins lots of future variable rate decisions, so it is a sound investment.

Soil sampling can provide another layer of information that can be used for precision nutrient management and other variable rate applications.

Precision nutrient management gives growers the ability to apply nutrients only where they are needed to optimise crop production, so it is a great way to save money and ensure that you are farming in an environmentally sustainable way. This nutrient information is used for variable rate base fertiliser and additional fertiliser applications during the growing season.

Depending on the soil sampling strategy (grid vs zonal sampling), costs can vary from $60/ha to just $200 for an entire paddock.

Drone or satellite imagery is best used for variable rate applications during the season. It allows you to vary applications depending on how the crop is performing in real-time so that you can deal with any issues before it is too late.

Satellite imagery is fairly cheap and is done without a field visit. This speeds up the turn-around time and reduces the cost for the grower.

Both options have their merits, and it depends on the issue you are addressing as to which will best give the desired outcome. Costs for drone imagery start from $4/ha and satellite from $400 per farm per year. GST exclusive.

At crop establishment, along with getting the right seeding rate for different areas, it is also important to consider the need for different nutrient levels across the paddock rather than take a blanket approach with a single rate.

Soil variability or crop history can mean that previous harvests have removed different amounts of nutrients from different areas of the paddock. This should be addressed to achieve maximise crop growth.

Variable-rate base fertiliser is a good way to start. This is linked to productivity potential, and once again, this can be determined by soil zones or grid soil sampling.

Once you have taken the initial steps needed to maximise the crop’s performance, the next step is to be proactive with crop management throughout the season. You can do this by using variable rate inputs of nitrogen, herbicides and insecticides.

Up-to-date crop imagery from a drone, satellite or crop sensors allows growers to make accurate management decisions, which could include variable rate applications to look after the crop.

We all know that seasonal weather changes can affect our crops during the season and to maximise the crop and minimise the cost of inputs we need to be able to apply only what is needed, where it is needed and when it is needed.

Variable-rate fungicide is great, particularly later in the growing season. Based on previous crop growth and weather events as well as weather forecasts fungicide can be applied at higher rates to areas with denser crop growth.

They are typically more at risk to disease pressure than areas of the crop that are less dense. Savings here can be quite considerable, based on the chemical being applied.

Critical to the success of using variable rate applications is the technology that can achieve it and technical support to pull it all together.

In addition to soil mapping and crop monitoring, this includes guidance and control systems that can recognise where different zones in a paddock are and seed drills, spreaders and sprayers that can work at variable rates.

Vantage NZ offers a robust range of Trimble guidance and control products that support variable-rate farming. They include the GFX-750 display system and Field-IQ crop input control system, and much more.

The Vantage NZ team also has the knowledge and experience to pull this technology together for you. They have a long history not only supplying and supporting these products in the New Zealand market but also using them on the farm.

For more information on variable rate crop management call Vantage NZ on 0800 482 682 or email info@vantage-nz.com.

Technology aids effluent management and reporting

Precision ag tools and technologies have long been used for a range of on-farm applications from variable rate nutrient management to machine guidance and control, and everywhere in between. The ‘right amount, in the right place’, saying applies to effluent management, equally as much as all other inputs on-farm. In 2020 we are blessed with a range of tried and tested tools and technologies to help ensure that effluent is managed as accurately and efficiently as possible.

To ensure that effluent is being applied ‘in the right amount, in the right place’ on-farm, soil moisture and environmental monitoring are key. Incorporating soil moisture monitoring into your effluent management ensures that you’re keeping an accurate record of how you’re affecting soil moisture levels with your effluent application, giving you the insight to adjust application rates based on soil moisture levels as required.

Another easy addition to an effluent-based soil moisture monitoring solution is a weather station, to record rainfall and help automate record-keeping of rainfalls compared to when effluent was being applied on-farm. Utilising an integrated solution through Vantage NZ, with the ability to also work off existing Halo Milk Vat Monitoring systems, ensures that you get the best value for money while ensuring that farm information is centrally stored for ease of reporting when it comes to compliance time.

While monitoring environmental factors to manage effluent is very important, likewise is proof-of-placement. Vantage NZ brings to the NZ market the industry-leading suite of Trimble Agriculture precision hardware. For farms that apply effluent through slurry spreaders, the Trimble GFX-350 with Precision IQ and Trimble Ag Software allows proof-of-placement maps to be easily captured, the slurry applicator controlled, and the map automatically sent through to the Trimble Ag Software for easy record-keeping once the job is completed.

To find out more about how Vantage NZ can help you with an integrated effluent management solution for your farm, call us today on 0800 482 682 or contact us info@vantage-nz.com.

 

Article published in: New Zealand Farming Life, October 2020

What is Precision Ag? Put simply it’s about using the right tools.

Precision agriculture can sound complicated and technical, but it is just an extension of everyday farming, says Jemma Mulvihill from Vantage New Zealand.

“Simply put, it’s about using the right tools and products for the right application to solve a problem. The results are better environmental management and farming efficiencies,” she says.

Since it started in 2010 Vantage New Zealand (formerly Agri Optics New Zealand Ltd) has grown to be New Zealand’s leading precision agriculture solutions provider. In February 2020 the company was re-branded and re-launched as Vantage NZ, combining the highly skilled and knowledgeable staff from both Agri Optics NZ and GPS Control Systems when the company purchased the Trimble dealership for New Zealand. Jemma says the result has been a more comprehensive suite of services, products and solutions covering the gamut of what farmers may require from one source.

“We are now New Zealand’s only full-time dedicated precision agriculture provider offering a full spectrum of products so we can assist farmers the whole way through the journey, making it more efficient and cost-effective for them to get the support they are after.”

With its head office in Methven and team based around the country Vantage NZ can provide precision agriculture service and support across New Zealand. Jemma says Vantage NZ has a great team offering many years experience, which is important to maximise the potential for clients and to support them all the way through.

She points to examples, such as electromagnetic soil surveying and soil moisture monitoring, as to how precision agriculture solutions can make a real difference to a farmer’s operation.

“By understanding the soil variability across a farm, this can inform irrigation and nutrient application decisions. For example, you might lower the amount of water placed on lighter soils or apply a little frequently, whereas, on heavier soils, you may be able to apply more. Savings in water usage and electricity can be a significant return on investment and also result in the farmer growing better crops. Similarly applying nutrients in the right amounts depending on the soil maximises potential without waste or negative environmental outcomes.”

Precision agriculture solutions can also help farmers to avoid some of the dreaded paperwork, she says. For example, the Trimble GFX-750 display can connect the entire operation with innovative, fully integrated software solutions that transform the way people farm by, for example, sending jobs to tractors from a cell phone or computer and generating farm proof of placement reports etc.

Jemma says because Vantage NZ was established off the back of on-farm use through its founders and directors, this gives a grassroots understanding of what farmers really need.  “Our key focus is on helping as many farmers as we can to implement precision agriculture in a sustainable and goal-driven way in their businesses. For us, that starts with understanding the customer’s issues and bringing solutions to the market that make a real difference.”

 

Article published in: Business Rural South, September 2020