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

1800 PRECISION AG (1800 773 247) INFO@PRECISIONAGRICULTURE.COM.AU PRECISIONAGRICULTURE.COM.AU

THANK YOU