Manaaki Whenua – Landcare Research is leading a new research proposal called Regenerative Agriculture, and is looking for a variety of growers and farmers to participate.
The research proposal is seeking government funding to bring together cutting edge science and innovative farming practices that will deliver:
This research project will measure a large host of on-farm indicators of environmental, economic, and social sustainability. For the full list see: https://www.facebook.com/WhereToForNZagriculture
Environmental sustainability measurements will comprise soil and biodiversity values. Soils will be assessed by measures of: soil structural qualities, soil function, and soil toxicity. Biodiversity will be assessed by: earthworm counts, bird, insect, and aboveground plant species richness, abundance of root symbiotic fungi and much more…
Economic sustainability will be assessed through the farm profit metrics of plant DM per ha, and $ revenue/DM less input cost.
Production quality will be monitored in forages and crops through dry matter, total fat and protein content, vitamin C and E concentration, available carbohydrates, as well as heavy metal content. Aspects of food safety will also be included such as pesticide and herbicide residuals in forages and crops. Animal welfare measurements will be included in pastoral systems, via physiological oxidative stress of grazing animals.
These measurements will be free, and available to the farmer or grower as they are collected.
For organisations, businesses, scientists, or other non-farming individuals wanting to participate in the Regenerative Agriculture project, register your interest here: https://goo.gl/forms/2leCr8nbrrDbTESl2
One of the four key areas within the Future Proofing Vegetable Production project aims to improve the accuracy of fertiliser applied. This work is part of the MPI Sustainable Farming Fund “Future Proofing Vegetable Production” project, co-funded by Horizons Regional Council, Potatoes NZ, Gisborne District Council, Ballance AgriNutrients and LandWISE.
Growers were invited to participate in having their equipment assessed. Equipment was tested with growers in both Horowhenua and Gisborne. Ten fertiliser applicators have been assessed through working with eight growers. Multiple settings or products were tested for some equipment.
In-Field Fertiliser Applicator Calibration Test
Performance
assessment of fertiliser application equipment provides information on actual
rates applied and the evenness of application. Ensuring that fertiliser is
applied evenly minimises the risk of leaching if over application occurs, or
the risk of yield penalties if under application occurs where nutrient
availability is limiting plant growth. Growers were confident their equipment
was spreading evenly, however the assessment results show there is room for
improvement.
Fertiliser
application equipment measured can be split into two main categories:
Direct placement machines (banders, side dressers and planters)
Figure 1: Examples of fertiliser application methods commonly used in vegetable growing systems: broadcast (left), potato planter (centre), and modified into 2 row bander (right)
Different methodologies are appropriate for broadcast versus direct placement equipment.
Broadcast fertiliser spreaders
were tested according to the FertSpread Protocol: see www.fertspread.nz
Power take off driven placement
equipment (banders or adapted oscillating spouts) were assessed by placing
buckets under the outlets and collecting fertiliser for a measured time (~30 –
60 Seconds). By determining travel speed the application rate can be
calculated.
Ground driven equipment (most
side dressers and planters) were assessed by collecting fertiliser from outlets
over a set distance in-field or from 20-wheel rotations in static testing.
Tests were repeated twice, however where results between tests appeared quite different, the test was repeated up to six times. For some machines multiple settings or fertiliser products were tested.
Direct placement machines were assessed using a calibration calculator that has been developed over the period of testing this equipment as there is currently no industry accepted assessment calculator available.
The draft fertiliser calibration calculator for the assessment of direct
application machines is included in the supporting documentation. This
spreadsheet calculates and reports a wide range of statistics to assess
performance.
The application variability of the direct placement equipment tested varied quite markedly; from 0.4% CV to 26.4% CV. A summary of the test results for direct application equipment is provided in Table 1.
Table 1
All but one of the machines tested are within the SpreadMark accepted performance for broadcast spreaders applying nitrogen-based fertilisers.
The actual rates of fertiliser applied varied from the target rates. In one case the actual average rate applied was 48% of the target rate, the greatest over application was 152% of the target rate.
Fewer broadcast spreaders were assessed as direct placement machines are more commonly used in intensive vegetable production systems. Table 2 provides a summary of the two broadcast spreaders assessed.
Table 2
Figure 2 gives a snapshot of part of the report produced through the FertSpread website. In this example, if the grower reduced their bout width from 22.5m to 19m, the machine performance would be within the acceptable level for nitrogen and non-nitrogen fertilisers.
Assessments have been
completed on a range of fertiliser application equipment in both Levin and
Gisborne. Most of the equipment tested has been direct application (banders,
planters and side dressers), rather than broadcast spreaders. Fertiliser applications for vegetable production are predominantly
applied as banded strips along the bed or scarified during planting or as a
side dressing. There is currently no accepted protocol for the assessment of
this type of equipment.
To enable the
assessments to be completed within the project, a draft protocol and fertiliser
calibration calculator for direct applicators has been developed and is being
refined. This is currently in an Excel spreadsheet which has been developed as
we have been testing equipment. The number of tests required and the statistical
analysis to report the suggested three key indicators is still to be discussed
and agreed upon. This concept and draft calculator will be taken to the annual
Fertiliser and Lime Research Centre conference in February 2019 for advice from
leading experts. The acceptable level of equipment performance and report
outputs provided to growers will be discussed.
It is currently
accepted for broadcast fertiliser spreaders that the coefficient of variation,
CV, should not exceed 15% for nitrogen fertilisers and 25% for non-nitrogen
fertilisers. The method of calibrating fertiliser rates applied ‘through the
spout’ to achieve target rates are accepted, however a different statistical
analysis is required for an assessment to be completed and best practice or
acceptable levels of variation need to be defined. It is suggested that a CV of
15% for nitrogen or even non-nitrogen fertilisers is well below the capability
of these direct placement applicators. Machinery in good working order should
achieve a CV of much lower than this, but an acceptable CV is not currently
defined.
This has opened discussion around how the acceptable CV is determined and if this is applicable in vegetable production systems. Our understanding is that accepted variance is based largely on pasture value and response curves, we query what values are appropriate for high value vegetable crops. Excess fertiliser increases leaching risk, insufficient fertiliser can make a crop unsaleable through quality loss. This is another area that it is felt important and worth further investigation.
The results of the
tests carried out on direct placement equipment highlighted several key areas
to address:
The target rate is not often achieved, the
results showed machines are both over and underapplying, which have
implications for leaching risk and potential marketable yield penalties or
decrease nutrient use efficiency.
In some cases, the outlets are not applying
fertiliser at equal rates. The cause of this is different for each machine. However,
the growers were keen to investigate why one outlet was applying a lower rate.
In one case the grower was able to fix the equipment and significantly reduce
the variation between outlets.
One machine resulted in different rates being
applied in each test. This is a greater concern for older equipment that is
worn and manually operated hoppers.
The amount of the fertiliser in the hopper appeared
to affect the rate of fertiliser applied. This suggests that as the hopper
empties that rate applied to the beds decreases. This also appeared to change
significantly with the bulk density of the fertiliser product. More testing is required
to investigate this further. There may be a minimum amount of fertiliser
(product/bulk density dependent) required to be in the hopper to achieve an
even application.
The interest and
engagement of growers through testing their equipment has built awareness. Once
a protocol is developed, the spreadsheet will then be developed into a tool for
growers. Prior to next season, workshops demonstrating how to calibrate
equipment, use the tool and interpret the report will be run in Gisborne and
Levin, with the possibility of visiting additional regions. Conversations with
growers during visits have shown there is good support for an event.
Broadcast
spreaders are less commonly used, and only two-disc spreaders were assessed. The
results showed that at the current bout width used neither machine was
achieving an acceptable CV for nitrogen fertilisers. One of the two was on the
limit of acceptable for non-nitrogen fertiliser products. This suggests that
the growers need to change either settings and/or bout width to achieve an
acceptable CV.
Reports are generated for all equipment we tested and distributed to growers. Some growers have requested that we re-test their equipment after they have made adjustments or prior to next season.
Irrigation assessments are important for ensuring the correct amount of water is applied to avoid yield lose due to moisture stress. However, excessive irrigation is a cause of nitrate leaching. A key aspect of our Future Proofing Vegetable Production project addresses keeping nutrient in the root zone. Through assessing irrigation uniformity and depth applied, machine and irrigation management can be improved.
This work is part of the MPI Sustainable Farming Fund “Future Proofing Vegetable Production” project, co-funded by Horizons Regional Council, Potatoes NZ, Gisborne District Council, Ballance AgriNutrients and LandWISE.
The irrigator assessments followed the ‘bucket test’ protocols as described in the Traveling Irrigator Performance Quick Test. In brief, buckets were place at 1m intervals across the path of the irrigator (see Figure 3). The speed of the irrigator was measured as it travelled over the buckets. Once the irrigator had passed over the buckets, the volume of water collected in each bucket was then measured. The data was entered into IRRIG8Lite software and reports generated.
Bucket test layout under a traveling boom irrigator assessed as prt of Future Proofing Vegetable Production project.
All three irrigators tested were traveling booms. The performance assessment was carried out twice on one of the traveling booms. An example of the distribution graph is provided in Figure 4. Of the four tests completed, the distribution uniformity assessment for two were ‘adequate’ and two were ‘poor’. The distribution uniformity for the four tests were 0.72 and 0.75 for the ‘adequate’ performing machines and 0.6 and 0.45 for the ‘poor’ performing machines.
Example distribution graph from a traveling boom irrigator assessed as part of the project
The results so far show that there is room for improvement in the performance of the irrigators tested so far. Higher than average rainfall has meant irrigation events have not been required as often so far this season. However, some growers briefly ran their irrigators to allow tests to be completed. We will continue to assess irrigators as we are able to access them over the coming months.
