| Autor: |
Leser, James F., Baugh, Brant, Boman, Randy, Doederlein, Tommy |
| Zdroj: |
Proceedings of the Beltwide Cotton Production Conference; 2004, p2182-2188, 7p |
| Abstrakt: |
COTMAN is an expert system developed by the University of Arkansas, which utilizes plant-mapping information to assist in making both early and late season management decisions. It can be particularly useful in identifying stress during the pre-bloom period affording the manager an opportunity to identify the cause of the stress and make management corrections. Since its inception in 1994, it has been involved in validation studies in over eight states. The SQUAREMAN component uses a default square shed limiter of 19% although user entered values ranging from 5-50% are available. This shed rate limiter is based on the plant's ability to compensate and the effect of this compensation through later fruit production on maturity and harvest. Studies in the Texas High Plains area have continued since 1996 to validate this model under our short season conditions. Of particular interest has been the shed rate limit of the model. We typically manage early season cotton fleahoppers and western tarnished plant bugs fairly aggressively allowing only 10% square loss the 1st week of squaring, 15% accumulative square loss the 2nd week and 25% accumulative loss for the 3 weeks prior to first flower. This aggressive approach can result in additional management costs and early disruption of beneficial arthropods resulting in flare-ups of aphids and bollworms. The results of a three year study examining the effect of varying levels of early manual removal of squares indicated no negative impact on yields or fiber quality at any level of square removal. There was however a delay in maturity penalty which could push harvest as much as 37 days later. The most important finding of this study was that for levels of square loss of 40% or less, there were not adverse effects on cotton production. The results from loss of squares from actual insect feeding may differ. The second most important finding was that because compensation was mainly through the increased retention of 2nd and 3rd position bolls, COTMAN would not adequately track compensation under the severest square loss conditions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Supplemental Index |
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