Seeder-based strategies to reduce the impact of water repellence on crop productivity

Page 1

2019

Seeder-based strategies to reduce the impact of water repellence on crop productivity Authors: Jack Desbiolles1, Nigel Wilhelm2, Melissa Fraser3, Lynne Macdonald4, Therese McBeath4, James Barr1 1 University of South Australia, Mawson Lakes, SA, 5095; 2South Australian Research and Development Institute, Urrbrae, SA, 5064; 3Primary Industries and Regions South Australia, Struan, SA, 5271; 4CSIRO Agriculture & Food, Urrbrae, SA, 5064 Funded By: GRDC CSP00203 Project Title: Increasing production on sandy soils in low and medium rainfall areas of the Southern Region Peer Review: Rodrigo Da Silva

Key Messages • • •

Low-cost, low risk seeder-based strategies achieved valuable wheat/barley crop establishment and grain yield benefits in a severely water repellent sand in two below-average rainfall seasons. Edge-row/on-row sowing and 230mm deep furrow till achieved the greatest crop benefits by exploiting existing in-furrow moisture (via guided sowing) and deeper moisture (via lifting by furrow opener), respectively. While adoption of these strategies involves RTK guidance, liquid dispensing and compatible seeding system technologies, scope for simplified solutions to reduce practical challenges exist and their performance should be tested in farm scale demonstrations.

Background Non-wetting sands have low fertility and suffer from delayed and uneven wetting, which leads to erratic crop establishment, staggered weed germination and generally poor crop productivity due to low plant densities, low nutrient access, poor weed control and crop damage in areas prone to wind erosion. A range of trials in the GRDC funded Sandy Soils Project (CSP00203) are investigating effective solutions available at seeding time to mitigate the impacts of water repellence. A range of seeder strategy experiments in the SA Mallee and in WA have demonstrated the potential for edge-row, on-row, paired-row and deep furrow till sowing to deliver establishment and yield benefits in water repellent sands. Another project trial conducted in a non-wetting deep sand at Lameroo during 2017-2019, quantified significant benefits of edge-row and on-row sowing on wheat and barley crop establishment and grain yield, while significant biomass and grain yield responses to 230mm deep furrow till were also measured (Desbiolles et al., 2019). In addition, experiments at Murlong on Eyre Peninsula (EP) have demonstrated some consistency in crop responses to wetters on water repellent sand (see soil wetter article of this series). The aim of this work was to test the impact of single and combined strategies that could be available to farmers around seed row location relative to stubble row (using RTK guidance), soil wetter (using liquid application), depth of furrow till (adjusting furrow opener to suit), opener type (knife point vs inverted T) and paired row sowing (vs single row baseline), with the aim to recommend a seeding strategy that maximises crop establishment and yield in a water repellent sand.

About the trial

A trial was set up at Murlong on EP in 2019. This trial was sown with barley on 20-22 May 2019 into 6 row wheat stubble plots established in 2018 on an RTK AB-line to ensure high accuracy when implementing row guided sowing treatments. The soil wetter (SACOA SE14 at 3 L/ha) was applied to the seed zone into 100 L/ha water volume. The seeding agronomy is summarised in the soil wetter article of this series. Two separate double shoot tine seeding systems were used, namely knife point side banding to achieve edge-row sowing and a baseline knife point centre row banding to achieve inter-row and on-row sowing, both followed by a 100mm wide banked press wheel. The 230mm


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