soil & landscape mapping technologies
TRANSCRIPT
Soil & Landscape Mapping Technologies
Brendan Torpy, Precision Agriculture
@AgPrecision
Actively manage PREDICTABLE and KEY YIELD CONSTRAINT issues
Direct map soil pH, Colwell P & Colwell K variability
Map soil/landscape variability – Texture, rooting depth, subsoil constraints, OC
Use NDVI and yield maps to record the success of above and help define problem areas for targeted actions
Precision Ag Principles
Our PA cycle
DATA
INSIGHT ACTION
Powering agriculture through the application of technology
Typical Precision Ag Road Map
1) Digital Farm Maps
2) Variable Rate Lime
3) Variable Rate P
4) EM38 & Topography Mapping – Gypsum, Nitrogen, Drainage
5) Satellite Imagery & Yield Data
Typical Precision Ag Road Map
1) Digital Farm Maps
2) Variable Rate Lime
3) Variable Rate P
4) EM38 & Topography Mapping – Gypsum, Nitrogen, Drainage
5) Satellite Imagery & Yield Data
Direct Soil Mapping
Rapid soil sampling and soil laboratory analysis enables grid:
Soil pH(cacl2) VR Lime
Phosphorus VR Phosphorus Potassium VR Potassium
Direct Soil Mapping
2ha sampling grid 8 x 0-10cm cores collected over 100m transect per 2ha
Each soil sample lab analysed at accredited lab
Strategic soil texture & PBI measurements
VR Lime South West VIC 51ha paddock, Pura Pura - Target pH 5.5 (CaCl2)
Traditional Approach (2.5t/ha lime blanket rate) = 128 tonnes
VR Approach (average rate = 1.1t/ha) = 56 tonnes
Lime Cost = $45/tonne (delivered & spread)
Lime Saving = 72 tonnes or $3,240 (56%)
Mapping Cost = $714
Total Saving = $2,526 (3.5:1 ROI)
VR Phosphorus Colwell P measurements on 2ha grid
20% savings without yield penalties
Integrate PBI, target yields into VR
decisions
45ha paddock, South West Victoria 10ha (22%) below critical Colwell P level 23ha (50%) standard rate
12ha (28%) reduced rate
Opportunities for 20-30% MAP savings
VR Phosphorus
VR Phosphorus Seeder vs Spreader
Seeder limitations limiting VR P – not wanting to vary traces/fungicides Seeding base rate
Pre-sowing VR P spreading
Science suggests surface spread OK if being applied for maintenance
purposes NOT for response that season
Typical Precision Ag Road Map
1) Digital Farm Maps
2) Variable Rate Lime
3) Variable Rate P
4) EM38 & Topography Mapping – Gypsum, Nitrogen, Drainage
5) Satellite Imagery & Yield Data
An EM38 sensor measures the bulk/apparent electrical conductivity of soils. Water Salts Clay Rock
Within the soil profile
Soil Conductivity Mapping
EM38 sensors are most sensitive to soil conductivity at depths of 0.3-0.5m and 0.75-1m.
Ideally mapped at drained upper limit or
when profile is completely dry
Why map your soils?
When it makes sense to do so!
When there is a clear link between soil type and production, thus potential for zonal management
Accurately defining known soil/landscape constraints such as salinity, sodicity, waterlogging and sand ridges
You may only need to map certain paddocks? Integrate into a Precision Ag Implementation Plan for your farm
Landscape Zoning – EM38 & Elevation EM38 & Elevation
One off investment Delineate soil texture zones, PAWC
Ground truth to understand soil
characteristics/constraints
Assist with gypsum, drainage and nitrogen management
Sandy Loam Organic Carbon 1.7%
Salt below 60cm
Sandy Clay Loam Organic Carbon 3.5%
3.8t/ha
2.5t/ha
Soil Conductivity (EM38) Survey 2015 Wheat Yield
Soil & Plant Relationships
Avoid trying to draw conclusions from years of historical data Focus on key years/crop types relevant to the issue being managed
First focus on yield unlock opportunities
Second focus on managing inputs to potential
Yield Maps and Farmer Knowledge
Prescription map with calibration strip
520ha
Crop establishment response to soil texture
Crop biomass (NDVI) tells the story
Potential Actions from Soil Maps
pH Mapping VR lime
Nutrient Mapping VR P & K fertiliser
Elevation Mapping Drainage Soil EM mapping coupled with zonal soil testing VR nitrogen * VR gypsum and manure * VR seeding* Crop rotations Strategic pest control*
* Integrate yield and/or NDVI data to develop strategy
Rapid Soil Analysis on the Horizon
X-Ray and Spectrometry technology Potential for instant results for soil
WHC, pH and numerous chemical and physical attributes
Use PA to help address key yield limiting constraints first
Focus on the need, not the technology!
Have a road map for implementing PA
Direct soil mapping - VR Lime & P
EM38 & Elevation mapping - VR Gypsum, drainage, N management
Integrate NDVI & Yield to develop yield unlock strategies
Summary
