Digital image analysis (DIA) can potentially provide rapid, objective assessment of pasture canopy development. In pastures of 'WW-B.Dahl' Old World bluestem [Bothriochloa bladhii (Retz) Blake], we compared the DIA programs ImageJ and Canopeo for ground cover estimates, their ability to estimate canopy functions, and their time savings for vegetation analysis relative to a manual method. The DIA procedure involved processing overhead canopy images into two color groupings corresponding to green ground cover and non-green (dead) cover plus bare ground for ground cover calculation. ImageJ analysis of ground cover agreed with two types of Canopeo applications (r 2 values of 0.97 and 0.98). The prediction regression for percentage photosynthetically active radiation interception (PARI) using ImageJ, y = 0.94x − 2.91 (r 2 = 0.72), was not different from Canopeo. Predicted values of leaf area index (LAI) and biomass increased exponentially with ground cover, likely owing to overlapping leaf area in older canopies. Two-dimensional ground cover had limited power of estimating LAI and biomass when ground cover exceeded 60%, LAI exceeded 1.8, and biomass exceeded 1500 kg DM ha -1 . The time required for estimating PARI, LAI, and green biomass using ground cover from both DIA methods was reduced to 3.6% of manual methods. The use of DIA with ImageJ provided measurements of ground cover that are simple and conducive to large batch analyses. Regressions of ground cover were deemed useful for rapid estimations of PARI and LAI, but of lesser value for biomass, especially when canopies developed stems and seedheads.Dep. of Plant and Soil Science, Texas Tech Univ. 2911 15th St., Lubbock, TX 79409.

The effect of ultrasonic-assisted extraction of carotenoids from corn with a 1:6 ratio of maize meal to ethanol (g g )1 ) was studied, and the extractive structure was analysed by FTIR. The results showed that at 12 min, the extraction concentration of carotenoids with ultrasound assistance was 3.6 times higher than that without ultrasound assistance. And the concentration of carotenoids obtained from using ultrasound assistance for 30 min was much higher than highest concentration of carotenoids obtained through magnetic stirring in 300 min. After studying multiple variables, the extraction concentration of carotenoids was higher using 700-900 W power, in 20 kHz frequency and at 38-40°C than that in other conditions. The activation energy of the extraction process was 44.61 KJ mol )1 . In addition, to achieve the best efficiency, the horn had to be placed deeper at the beginning of extraction and then raised at the 12 min point to 4.70 cm from the bottom of the beaker. By using FTIR analysis, we concluded that the structures of the corn carotenoids were not destroyed by ultrasound assistance.

Spring establishment of cool‐season annual grasses into poorly producing orchardgrass (Dactylis glomerata L) (OG) swards may improve forage production and nutritive value in the southeastern United States following a fall drought. A randomized complete block experiment was conducted where annual ryegrass (Lolium multiflorum Lam.) (AR) or forage oat (Avena sativa L.) (FO) was interseeded into an existing OG stand over three seeding dates with (+) or without (–) a burndown herbicide (BD) treatment and compared with an OG monoculture (control). In 2017, after a warm and wet winter, the OG monoculture (control) was able to produce sufficient forage mass (FM) without significant reduction in nutritive value as compared with OG interseeded with AR or FO. In 2018, OG had approximately 2,600 lb acre–1 less FM than in 2017, suggesting that recurrent fall drought with unfavorable winter conditions resulted in long‐term damage to the perennial sward. Meanwhile, treatments without BD did not show higher FM in the beginning of the season. Burndown treatment in general increased FM and nutritive value. An economic analysis of the study also revealed results suggesting that interseeding AR and FO in the spring is not economically viable, as it may cost up to 10 times as much as the control.