While most regions are down on area this season due to the prolonged drought, we are ‘one day closer to it breaking’. Many growers have fields ready to go when we get good rain in November and December. We also know how quickly some of our major dams can fill, as seen in 2012 and 2016.
While it has been a hard and frustrating few years for dryland cotton farmers and summer croppers in general, it only takes a couple of good rainfall events to give growers the opportunity to plant.
Work that was carried out by Warren Conaty, CSIRO has shown that one irrigation (or rainfall) event applying at least 47mm to the crop in a dryland farming system will put on a one bale per hectare. Hence, over a two month period through January and February if reasonable rainfall fell, good yields could still be achieved.
Source: Conaty.
The beauty of cotton is its indeterminate growth pattern. Unlike many determinate plant types, such as corn or sorghum, cotton has the ability to fruit over a long period of time and responds well to rainfall.
As an example, Angus Vickery’s double skip dryland crop at Bellata was virtually dead in the 2017-18 season at the end of January, with very little subsoil moisture and large cracks occurring across the profile. He had planted the crop on rainfall in December with very little rain occurring from planting until the end of January. Plant map data suggested this crop would yield well below average, with 17 nodes and 2 bolls per plant (6 plants/m). The estimated yield was around 0.4 b/ha.
In late February, with open bolls at the bottom of this crop, the region received 70mm of rainfall. Angus had a hard decision to make, to harvest what was there, plough the crop in or restart the crop and pick later in the year. Even though it wasn’t ideal growing the crop out into the Autumn months, he continued growing the crop and with further rainfall through March, the crop developed around 8-10 bolls/plant. It was picked in May and yielded around 2.69 bales/ha. A great result considering there was very little rain early on in the season and the crop had to be virtually restarted.
2017-18 Angus Vickery – “Dobikin” Bellata.
Cotton’s ability to recover and compensate in these situations allows growers to make informative decisions based on past trial data, that in this case paid off, and could be the difference between making a profit or loss.
CSD’s new ‘BARRY’ app (Biometric Agronomy for Realising Representative Yield) will give growers a tool for assessing crop growth and a predictive yield at any stage of the crop’s life. This will help with making those tough decisions in hard years, in combination with future weather forecasts.