Search Results

Mulch surface color affected the growth of bell pepper (Capsicum annuum L.) plants, the amount and quality of upwardly reflected light, and the soil temperatures under the mulch. Of the surface colors evaluated (black, red, yellow, and white), plants grown over red mulch were the tallest. The darker (black and red) mulches reflected less total light and more far-red (FR) relative-to-red (R) light, and soil temperatures recorded in the afternoon and evening were warmer than under the yellow and white mulches. Plant growth responses to mulch surface color were also observed when soil temperature differences among the mulch color treatments were minimized by placing insulation boards between the mulch surface and the soil. Sensitivity of young pepper plants to a high or low FR: R light ratio was demonstrated by exposing plants to 15 minutes of FR or 15 minutes of R light at the end of the photosynthetic period each day for 14 consecutive days in a controlled environment. Plants that received the FR (high FR: R ratio) were 51% taller than plants exposed to R (low FR: R ratio) light treatments. The similar responses of pepper plants to differences in FR: R ratios associated with mulch color and end-of-day light treatments provide evidence that pepper plant growth is affected by relatively small changes in light environment induced by the surface color of the mulch.

The influence of mulch types (black polyethylene, red polyethylene, and straw-vetch in raised bed hill culture) on the chemical composition of `Northeaster' and `Primetime' strawberry (Fragaria ×ananassa Duch.) fruit and plant parts was evaluated. Ascorbic acid (AA), malic acid, citric acid, and ellagic acid levels were higher in `Primetime' than in `Northeaster' fruits, while `Northeaster' had a higher soluble solids content (SSC). Fruit grown on straw-vetch had lower SSC than did those grown on the polyethylene mulches. The AA content in the fruit of either cultivar was not affected by the mulch treatment. Fruit grown on the straw-vetch mulch had less red surface and flesh color but higher pigment intensity than fruit grown on the polyethylene mulches. Strawberry plants grown on straw-vetch mulch had the largest leaf area and the highest chlorophyll content, while plants grown on red polyethylene mulch had the smallest leaf area and lowest chlorophyll content. There were significant mulch × cultivar interactions in fruit titratable acid (TA) and AA levels, sugars, citric and ellagic acid contents, leaf area and chlorophyll levels, and soluble carbohydrate and starch contents in leaves, petioles, crowns, crown-roots, and roots. TA was highest in `Northeaster' fruit when grown on red polyethylene, whereas TA was highest in `Primetime' fruit when grown on straw-vetch. The highest fruit citric acid levels were found in straw-vetch mulched plots of `Northeaster', and in black polyethylene mulched plots of `Primetime'. Ellagic acid accumulation was highest in `Northeaster' fruit grown on black polyethylene, and in `Primetime' fruit grown on red polyethylene or straw-vetch mulches. Fruit glucose content was highest in `Northeaster', but lowest in `Primetime', when grown on the straw-vetch mulch. There was a general tendency for soluble carbohydrate and starch levels in plant tissues to be lowest when the plants were grown in red polyethylene mulch and highest when grown in black polyethylene mulch. `Primetime' contained higher total carbohydrate levels than did `Northeaster' in all tissues tested.