Seasonal Forage Biomass Production By Winter Canola and Wheat Under Different Irrigation Levels in the Southern High Plains.

Need to modify as soon as possible

In mixed farming systems dual purpose crops can provide high quality forage for livestock during forage deficit periods and regrow to produce seed yield. Winter wheat is the dominant dual purpose crop used in the Southern High Plains (SHP). There is a need to rotate winter wheat with crops those offer rotational benefits, reduce grass weed problems in continuous wheat system, and diversify the system to improve economics and sustainability. Winter canola ideally fits in the rotation, but its dual purpose potentials are not fully researched. A study was conducted at Agricultural Science Center at Clovis, NM over three seasons (2008-2011) to compare the seasonal patterns of forage biomass production by winter canola (cvs. Rally and DKW 41-10) to that of winter wheat (cv. TAM-111) under six irrigation levels. Irrigation levels ranged from rainfed (irrigated only to establish the crop) to 25% higher than the estimated evapotranspiration of winter wheat. Growth pattern of winter canola and wheat differed. Unlike winter wheat, canola produces biomass quickly in the fall. Once the killing freeze occurs, canola goes dormant and doesn’t produce any new biomass till spring regrowth starts. During severe winter months it also loses most of its lower leaves to freeze. This sometime leads to lower biomass early in the spring when regrowth starts. Winter canola regrowth (leaves and flowers) are quite sensitive to freezing temperatures. In contrast, winter wheat continues to grow in winter months at much slower rates. It utilizes occasional warmer conditions in the winter to add biomass. Regression of forage biomass production and total water use by both winter crops were similar in those years in which, spring regrowth of winter canola was not severely damaged by the late spring frost. The data on seasonal patterns of forage production and weather conditions will be presented.