An Explanation of the Planting Forecast Score
CSD has a number of weather stations with soil temperature sensors placed across many regions of the cotton industry, which form the FastStart™ Soil Temperature Network. These sensors are a real-time measure of the soil temperature at 10cm and can be used as a guide to whether conditions are suitable for planting cotton in the areas where they are situated.
Ensuring that soil temperature is above 14°C at 8am (AEST), as well as checking that the forecast temperatures for the week following planting are on a rising plane, will give the ‘green light’ for planting.
The FastStartTM Cotton Green Traffic Light recommendation for cotton planting is:
- 14°C at 8am AEST.
- Rising temperature forecast for the seven day period post planting.
When making planting rate and timing decisions, growers and consultants should take note of the the forecast score for their region. The forecast score provides an indication of the potential day degree accumulation, based upon the proceeding seven day forecast. The forecast score is a guide only to assist growers and consultants of conditions and enable adjustments to planting rates if required. It is not intended to be used as an accurate tool and should be utilised solely as a guide to refine the decision making process. Figure 1 and Table 1 show an example of where to locate the forecast score, as well as an explanation of how to interpret the score.
| < 30 DD | Very Poor | Do not plant. |
| < 60 DD | Poor / Caution | Warrants caution as a delay in emergence is likely and may impact upon germination percentages and/or exacerbate seedling disease or soil insect attack. Management intervention is encouraged. |
| 61 – 80 DD | Adequate | Considered adequate, however ensure other planting parameters and conditions are ideal. Cotton will likely take greater than seven days to emerge. |
| > 81 DD | Good | 81 or more day degrees is considered as the requirement for ideal germination and emergence. |
Table 1: Interpreting the planting forecast score.
The diverse environments in which cotton is grown in Australia mean that a rising plane of temperature can be quite different from one area to another. For example, in Griffith in September, a rising plane could mean an increase from 5°C to 7°C whereas for Bourke this could mean from 15°C to 17°C for the same dates of the year. As such, crop establishment can be affected.
Cotton growth is influenced heavily by temperature, especially during the early phases of crop development. It normally takes between 80 to 100 day degrees to emerge, once water is taken up by the seed. This can vary depending on soil strength and planting depth, but as a general rule this is the standard for cotton. The forecast score is the accumulation of the day degrees for that particular location for the following seven days. A scale of various zones has been assigned to different ranges of the forecast score to indicate the likelihood of the cotton emerging within seven days.
The accumulation of 80 to 100 day degrees can vary significantly from area to area, as illustrated in the following examples:
EMERALD, CENTRAL QUEENSLAND
The accumulation of 80 to 100 day degrees can vary significantly depending on planting date and from area to area, as illustrated in the following examples from Emerald and Theodore. The revised planting window has now being in effect for a number of seasons and has had a major impact for when Central Queensland and the Dawson/Callide region plant cotton.
Many growers plant as early as possible to take advantage of the longer season. However, caution should be taken during an August plant, due to the risk of frost and a potential decline in forecast scores. An example of this can be seen in Figure 1. This is also mirrored in Figure 2. During the 2020-21 season, there was a spike in the forecast in early August however this declined to around 50 until late August early September. Based on the forecast score, conditions are usually adequate for planting from early to mid-September onwards.
Figure 1: Five year forecast score Emerald.
Figure 2: Five year forecast score Theodore.
© Cotton Seed Distributors Ltd 2022. General guide only; not comprehensive or specific technical advice. Circumstances vary from farm to farm. To the fullest extent permitted by law, CSD expressly disclaims all liability for any loss or damage arising from reliance upon any information, statement or opinion in this document or from any errors or omissions in this document. Roundup Ready Flex®, Roundup Ready®, Bollgard II® and Bollgard® 3 are registered trademarks of Monsanto Technologies LLC, used under licence by Monsanto Australia Ltd. Insect control technology incorporated into these seeds is commercialised under a licence from Syngenta Crop Protection AG. Sicot, Sicala, Siokra and Sipima cotton varieties are a result of a joint venture research program, Cotton Breeding Australia, conducted by CSIRO and Cotton Seed Distributors Ltd (CSD). CSD is a partner in the CottonInfo joint venture, in partnership with Cotton Research Development Corporation and Cotton Australia.