Regulated deficit irrigation and cotton production responses in southwest Texas
Wen, Yujin, author
Piccinni, Giovanni, author
Cothren, J. Tom, author
Leskovar, Daniel I., author
Rowland, Diane, author
Kemanian, Armen R., author
U.S. Committee on Irrigation and Drainage, publisher
The urban water demand in Southwest Texas has grown rapidly in recent years due to large population increase. Regulated deficit irrigation (RDI) is one important measure for saving water while maintaining crop yield/ net benefit. An RDI field experiment was conducted at the Texas AgriLIFE Research and Extension Center at Uvalde in the summer of 2008 to examine the water saving potential. Seven irrigation schemes and four varieties were assigned to the experimental field to test their effects on lint yield. The results showed that: 1) The threshold of the replacement ratio is between 0.7 and 0.8 in fixed ratio irrigation schemes. Dynamic irrigation schemes showed a higher potential to save irrigation water. 2) The fiber quality was affected more by varieties than by irrigation schemes. A 50X (fixed 50% ratio) scheme has the potential risk to produce relatively lower quality cotton fiber by affecting fiber length and fiber yellowness. Considering its negative effect on lint yield as well, the 50X scheme is definitely not recommended. The two dynamic irrigation schemes, 50D and 70D, showed no negative effect on fiber quality. The 70D scheme has some potential to increase the fiber quality in fiber length, uniformity, fiber strength and reflectance; however, this scheme uses more irrigation water that the 50D scheme. Although further research is needed before making definitive conclusions, both dynamic schemes could be applied to maintain lint yield and fiber quality while saving more water, compared to the fixed ratio irrigation schemes.
Presented at the fifth international conference on irrigation and drainage, Irrigation and drainage for food, energy and the environment on November 3-6, 2009 in Salt Lake City, Utah.