Trengove Consulting trials

To investigate amelioration options for sands that have low water holding capacity, low organic matter, low nutrient availability, compaction, non wetting and high risk for wind erosion.

The aim of this project is to improve the capacity of growers to identify and manage subsurface acidity on the Northern Yorke Peninsula. Soil testing and pH mapping for acidity has become common practice in the district. However, this sampling and mapping has focused on the top 0-10 cm of soil. Recent reports and preliminary work have confirmed an acidic band of soil is often occurring at the 5-15 cm depth and beyond in certain soil types.

There are two main components to this project:

• Spatially identifying subsurface acidity by validating the relationship between soil pH and EC (electrical conductivity).
• Develop best management practices for lime amelioration to manage subsurface acidity.

To examine crop safety and broadleaf weed control implications for various herbicides and combinations in lentils.

To better understand best practice management of WPM given emerging fungicide resistance issues.

For trial results please see attached report. 

This project aims to establish field sites which demonstrate amelioration techniques that growers can use to address the specific sandy soil constraints for their local landscape type and where in the landscape different tactics are best deployed.  

This project aims to establish field sites which demonstrate amelioration techniques that growers can use to address the specific sandy soil constraints for their local landscape type and where in the landscape different tactics are best deployed.  

This research aims to trial and demonstrate different management practices which could be used by growers to ameliorate saline soil patches:

1) Amending soil with sand, straw or gypsum - application of amendments to the soil surface can improve crop emergence by reducing evaporation leading to more soil moisture, or by reducing the moisture required to germinate a seed by increasing the sand content of the soil surface. Gypsum was also included to increase the amount of calcium relative to the level of sodium (salt) and address sodicity in the longer-term.  

2) Selecting crop types/varieties – to investigate the differences in crop performance on saline soils between crop types and varieties with improved salt tolerance.

To investigate non aggressive strategies to mitigate and manage non wetting sandy soils. These strategies include seed row placement, press-wheel design and the use of soil wetters / surfactants.

Trial 1: Lime comparison trial 
The use of new pH mapping technologies has increased the awareness and identification of soil acidity in many districts. However, there are several aspects of soil acidity management which remain a problem for growers. This trial aimed to investigate a range of lime and acidity management factors outlined in the three key areas below. 

• Lime source 
• Lime rate and particle size 
• Decline of soil pH from sulphur applications 

Trial 2: Comparison of lime incorporation techniques 

Acidic layers of soil are increasingly being identified in the topsoil (0-10 cm) and subsurface soil (10-30 cm) of no-till farming systems. Stratified low pH soil layers need appropriate lime treatment to maintain and prevent the decline of soil pH further. Surface application of lime alone is unlikely to raise the pH in subsurface layers quickly. Recent work has reported lime movement as little as 1 cm – 2.5 cm per year (Fleming et al. 2020, Burns et al 2017). Given the slow movement of lime, incorporation and mixing of surface applied lime to depth is expected to accelerate the movement of lime.

There are a range of machinery options that can provide different levels of lime incorporation and to different depths, such as cultivation, deep ripping with or without inclusion plates, spading and combinations of these. This trial was designed to investigate which of these are most effective on a sandy soil with stratified soil acidity at Bute.

This trial is part of a larger series of experiments in the southern region aiming to compare the productivity (yield, protein), profitability (gross margin, risk) and sustainability (soil organic matter, carbon footprint, N losses) of different N management systems over the long term.

There are a range of machinery options that can provide different levels of lime incorporation such as spading. However, research to date on rotary spaders has shown soil/amendment mixing is not uniform due to the cyclical process, and the mixing quality reduces significantly at faster speed (Ucgul et al. 2019). This trial aimed to understand how the uniformity of soil-lime mixing by spading affected crop response and soil pH. 

The objectives include validation of the effectiveness of varietal resistance, application rates and timing, efficacy of pre and post emergent fungicides to assess how different actives (DMI, QoI and SDHI fungicides) perform in the presence of resistant powdery mildew mutations.

In 2022 the project had three main field components

• Investigating best management of wheat powdery mildew through small plot trials.
• Surveying grower paddocks to determine frequency of mutations conferring reduced sensitivity or resistance to DMI and QoI fungicides.
• Understanding the cause of spatial variability in mildew incidence related to soil type. Collecting samples from for nutrient analysis.