Inventor: Prof. Dr. Kudhair Abaas Jadooh, Lecturer. Dr. Mohammed Fawzi Hamza, Assist. Lecturer. Jamal Waleed Mahmoud/Department of Agricultural Engineering Sciences, College of Agriculture, University of Baghdad
Any Plant develops and grows according to highly ordered, organized and complicated series. This growth and development strongly depends on temperature, besides, other factors. There are many growth scales for monitoring and description the growth of cereals including wheat, the most famous and widely used one isZadoks growth scale. However, this scale is not accurate as it depends on the naked eyes in describing the growth stages, hence, when it is used the crop management is UN efficient. Next to the Zadoks scale is the calendar date scale which is based on the time (e.g. Days) from sowing date to a certain growth stage. This scale is also UN accurate, in fact, it is misleading to the farmers as temperatures might differ from year to year and from site to site. Therefore, a more accurate and efficient scale is strongly needed to accurately predict the growth stages of wheat and its relationship with the crop management.
This scale depends, not on the ordinary temperatures, but on so called growing day’s degrees (GDD). We have discovered, in Iraq, after a series of experiments over a decade that, irrespective of wheat variety, sowing dates, growing season, site, seeding depth, nitrogen rate etc., the values of (GDD) were almost the same everywhere to reach the certain growth stage. This discovery, after its confirmation, encouraged us to design a new scale depend upon the (GDD) concept. It was named as thermal scale for wheat growth and development and its relationship with crop management. Simple equations can be used to obtain GDD values. These values will lead us to the certain growth stages to apply the crop management at this stage towards increased crop productivity. This new scale is characterized by its global use as the (GDD) values, simply, are the same everywhere in the world. In fact, this is the main characteristics of this new discovery as no one in Iraq or elsewhere discovered such fact before us. In order to make this new scale easy in its application by farmers or researchers, a simplified curve of wheat life cycle (poster) was designed with (GDD) values from sowing date to the critical growth stage and for each stage the components of crop management.