Short Season Pitfalls
PLANTING CHALLENGES
There are two main factors that will influence the success of your establishment. This is a combination of your soil temperature at 10cm depth at 8am and forecast temperatures at the time of imbibition. Research by Constable and Shaw 1988 (Table 1) have shown that minimum soil temperatures at 10°C will take 29 days to complete emergence with only 56% of seed survival. In 14°C soil temperatures it will take 17 days to complete emergence with a 73% seed survival.
| Minimum soil temperature at 10cm | Seed emerging and survival rate | Days to complete emergence |
| 10°C | 56% | 29 |
| 14°C | 73% | 17 |
| 18°C | 90% | 5 |
Table 1: Effect of temperature on cotton seedling survival and growth rate (Constable and Shaw 1988).
In the Southern NSW region there is only one planting window to plant cotton, starting from when the soil temperature is on a rising plane and nearing 14°C – usually early October. Replant immediately caps yields as this decision is usually made at least 2 weeks after seed imbibition (17 days to emerge when planting in ideal 14°C soil temperatures) and this puts the replant into very late October or early November. Data has shown that planting past the end of October in Southern NSW reduces
yield by 2 bales/ha.
By planting early into soil temperatures at 10°C the plant can take a minimum of 29 days to emerge as a cotyledon. The CSD seed treatments applied only provide insecticide and fungal control for 2-3 weeks depending on the seed treatment. Therefore, the insecticide and fungal control products are being consumed for the period of
emergence. There will likely be no protection against the immediate pests and diseases the cotyledon will be exposed to after emergence, if the decision is made to plant into less than ideal conditions.
Sensitivity of cotton to cold temperatures during the germination period. Source: Texas Cooperative Extension.
Federation Farm soil temperature at 9am EST.
PLANTING TO THE CONDITIONS
The cotton planting window in Southern NSW is a short and critical period each season. Understanding what your soil temperature is at 8am at 10cm depth for a continued period of time leading up to and during planting can significantly impact the success of your establishment.
CSD members have access to the Soil Temperature Network which provides a traffic light system to assist you with your planting decision – go (green), wait (amber) or stop (red) – is based on live soil temperatures and forecast weather (day degree accumulation) for your location. The Soil Temperature Network uses actual temperatures to determine that; planting can begin when soil temperatures reach 14°C at 8am for three consecutive days; and planting can begin when there is a rising plane of temperature forecasted above 14°C for the next 7 days.
Figure 1: Effect of 7 day germination test at a range of constant temperatures on the same AUSlot.
DAYS TO FIRST FLOWER
The 2021-2022 planting period is shaping up to be challenging start under different circumstances from previous seasons. Cool conditions are delaying the increase of soil temperatures and forecast day degree accumulation and as a result soil temperatures are well below the ideal 14°C. Another useful decision tool can be accessed by CSD members to help decide whether planting early is really the best decision. STEFF (Simulated timing to estimated first flower) can be used to in the following way. By using two different planting dates, one early and one in the ideal planting window for your location, STEFF predicts when First Flower will likely occur.
| Location | Planting Window | Imbibe Date | STEFF First Flower Date | Days to First Flower |
| Coleambally, NSW | Early | 28th Sep | 30th Dec | 93 days |
| Ideal | 10th Oct | 4th Jan | 86 days |
Table 2: Coleambally STEFF prediction using early and ideal imbibition dates 2021.
From this example, planting 12 days later on the 10th October places first flower only 4 days later than the early plant first flower date. The decision to begin planting in not simply a calendar date.
© 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.