Merriwagga Regional Site

The Merriwagga Regional Site is operated in association with a local committee of farmers, DPI staff and other agencies.

Chairmen: Lawrence Higgins 02 6965 1419

DPI District Agronomist: Barry Haskins 02 6960 1320

CWFS Trials and Extensions Agronomist: Caroline den Drijver 02 6895 1016

Co-operators: Ian & Geoff Barber “Sylvanham” 6967 6202

Long Term Crop Rotation & Tillage Trial

In 1999 the Merriwagga Regional Site Committee established a long term farming systems trial to investigate the sustainability and profitability of 4 cropping rotations and 2 tillage methods in Merriwagga. The paddock chosen had a long history of traditional low input cropping. Soils are alkaline red earths (pH 6.8 CaCl2), with a layer of limestone within 60cm of the topsoil.

The long term farming systems trial is located on Geoff and Ian Barber’s property “Sylvanham” on the corner of Black Stump Rd and Greenhills Rd, approximately 10kms SW of Merriwagga. The Barbers have allowed the Merriwagga Regional Site group to share-farm the trial site, allowing other trial work to be conducted around the farming systems trial. The trial is designed so that all operations are conducted using growers equipment to make it realistic. The trial has been set up with 3 replications of all treatments, totalling 30ha in area (trial plan).

1: Continuous rotation cropping: This system involves continuous cropping by rotating crops. When the trial began, this system was not common practice, and it is designed to see if it can be done economically in this environment. Since the beginning of the trial, more growers are now using break crops. In general, a break crop is grown every second year after wheat. The choice of the break crop is mainly determined by the time of break, and disease risks.

2: Continuous Wheat: This treatment is not common in the area, however growers wanted to see what happens if wheat is grown over a long period of time. .

3: Wheat/Ley/Fallow/Wheat: This system has traditionally been practiced, however is declining as stock numbers reduce. After harvest the paddock is left as a ley, where naturalised grasses and legumes emerge. The paddock is grazed until it is brought into fallow the following year. Cropping occurs every third year in this system.

4: Wheat/Fallow/Wheat: This is also a traditional cropping system still practiced by some growers. The paddock is cropped every second year and fallowed in between aiming to conserve soil moisture, mineralise nitrogen, and break disease cycles.

Each of the above cropping systems is divided into two tillage treatments. These are:

1: No tillage: This treatment involves sowing with narrow points into an unprepared seedbed. Weed control is by herbicides and in some cases burning. To the extent to which it is practical, the plots are not tilled in any way. Due to machinery limitations, nitrogen may be predrilled prior to sowing using narrow points, harrowing may occasionally be practiced to remove excess stubble or weed residues that may hinder sowing.

2: Multiple tillage: This system uses conventional tillage fallows and tillage to prepare the seedbed and remove/incorporate stubble. Herbicides are still used in this system, however cultivation is the primary method of weed control. This treatment aims to emulate common tillage practices of the district when the trial began.

The Merriwagga Regional Site group would like to thank the site sponsors who donate their time, money and products to allow the long term farming systems trial to be the success that it is today.

GRDC, NSW DPI, Elders, Rawlinson and Brown, Landmark Griffith, Yenda Producers, Agrichem, AWB Seeds, Bayer, Case Intersales, CropCare, Codemo Machinery, Commonwealth Bank, Computer Concepts, ECOM Commodities, Dow AgroSciences, Dupont, Farmoz, GrainASSIST, Harrison Spray Contracting, Harry Shaddock Seed Grading, HiFert, Incitec/Pivot, Intersales, Mobil, Nufarm, Pioneer Seeds, PlanTech, RABO Bank, Pioneer, Suncorp, Syngenta, Vic Chemical Co, Murrumbidgee and Lachlan CMA’s.