Abstract
The potential, or energy-limited evapotranspiration, and the actual, or soil water-limited evapotranspiration functions of sunflower were estimated by lysimetry and field soil water measurements. The functions show that peak water demand by the crop is in the immediate post-anthesis period and that sunflower is capable of restricting its water use when some 70% of the maximum available water remains in the root zone. With the aid of these functions, weekly estimates were made of the water use of thirteen commercial sunflower crops in northern New South Wales. Estimated water use ranged from 150 to 320 mrn and water use efficiencies from 1.9 to 10.5 kg seed mm-1 water used. Highest yields and water use efficiencies were associated with a combination of high total water supply (soil water at sowing plus rainfall during growth of 380 mm or more) high water use (220 mm or more) and low evaporative demand (below 780 mm of pan evaporation). Based on the water use characteristics of the crop the optimal sowing time in most areas is mid summer. However, spring sowings may be preferable for winter rainfall areas where soil water storage capacity is high and there is only a small component of summer rain. Crops sown in spring, even with high stored soil water (up to 200 mm) failed to yield as well as those sown in summer with much lower soil water storage.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.