al., 1990 ; Kasperbauer, 1992 ). Row covers are used to insulate a plant's growing environment to promote early yield. Floating spun-bonded polyester row covers are used with various vegetable crops ( Shadbolt et al., 1962 ; Wells and Loy, 1985
Garry G. Gordon, Wheeler G. Foshee III, Stewart T. Reed, James E. Brown, and Edgar L. Vinson III
Warren Roberts and Julia Whitworth
A factorial experiment with four mulch treatments (clear, black, or IRT plastic, and a non-mulched control), two planting types (seed vs. transplants), and two row cover treatments (with and without) was initiated to determine the harvest date of watermelon with these treatments. Experiments were planted in the field April 7. Row covers (Kimberly Farms, spunbonded polypropylene, 20 g·m-2) were suspended on wire hoops above selected plots. Soil temperatures at 5 cm, measured at noon, were lower in plots with row covers. On May 13, the row covers were in the process of being removed when a thunderstorm developed. One guard row remained covered during the storm. Hail ranging from 1.3 to 2.5 cm in diameter fell for 30 minutes, with a final accumulation of 5 cm of hail and 10 cm of rain. There was no noticeable difference between transplants and direct seeded plants, or among the different types of mulch, on resistance to hail damage. All plots that were not covered with row covers were totally destroyed. However, the area on which row covers had not been removed received only minor damage.
D. J. Makus and A. R. Gonzalez
Black and white plastic row covers were established over field-grown `Jersey Giant' asparagus on 10 Mar 89. Season soil temps in uncovered, white, and black plastic treatments were 17.4, 15.9, and 16.8°C, respectively. Night air temp under plastics was about 1.4°C higher than no plastic. Day temps under black plastic were typically >10° higher than no cover. Temps under white plastic were intermediate. Spears were cut for 7 weeks beginning on 27 March. Black plastic improved early yield only at the third cutting week. There was no consistent plastic cover effect on spear diameter. Marketable and total yield were improved with the use of plastics. Spear number/ha was not affected. Spear weight (after trimming to 15 cm length) was greater when grown under plastic, whereas spear length was reduced. There were no differences between treatments in spear fiber, but spears grown under plastic covers had higher soluble solids and nitrates, and lower ascorbate, protein and phenolic levels than did uncovered spears. Very little chlorophyll and carotenoids were produced in the absence of light, but there was a color intensity difference between spears grown under the two different plastics.
D. J. Makus and A. R. Gonzalez
Black and white plastic row covers were established over field-grown `Jersey Giant' asparagus on 10 Mar 89. Season soil temps in uncovered, white, and black plastic treatments were 17.4, 15.9, and 16.8° C, respectively. Night air temp under plastics was about 1.4° C higher than no cover. Day temps under black plastic was about 10° C higher than no cover. Temps under white plastic were intermediate. Spears were cut for 7 weeks beginning on 27 March. Black plastic improved early yield only at the third cutting week. Marketable and total yield were improved with the use of plastics. Spear number/ha was not affected. Spear weight (after trimming to 15 cm length) was greater when grown under plastic, whereas spear length was reduced. There were no differences between treatments in spear fiber, but spears grown under plastic covers had higher soluble solids, sweetness rating, titratable acidity and nitrates and lower ascorbic acid, protein and phenolic levels than did uncovered spears. Very little chlorophyll and carotenoids were produced in the absence of light, but there was a color intensity difference between spears grown under the two different plastics.
Stephen Reiners and Peter J. Nitzsche
Three tomato varieties were evaluated for early and total yield using row covers. Tomatoes were planted three weeks earlier than the normal planting date and row cover treatments included; 1) slitted, clear polyethylene 2) floating, spunbonded, polypropylene and 3) bare, no row cover. `Pilgrim', `Celebrity' and' Mountain Pride' were selected as early, mid-season and late varieties, respectively. Row covers were removed after three weeks at which time a second planting was made, representing the normal planting time. Slitted, clear, polyethylene row covers significantly increased early yields in all varieties as compared to the bare treatment. In addition, clear row covers resulted in higher early yields in `Pilgrim' and `Mountain Pride' than floating row covers. Despite row covers over `Celebrity' and `Mountain Pride', early yields were still not as great as the `Pilgrim' cultivar without any row cover.
Mack A. Wilson, Victor A. Khan, and Clauzell Stevens
Four types of row covers were evaluated on two cultivars of potatoes (`Atlantic' and Frito-Lay 795') at Charleston, Missouri on sandv loam entisol. Row covers used were spunbonded polyester, clear and white slitted and VisPore. Significant interactions occurred in the sub-plot (row cover × varieties) and sub-subplots (varieties × flower treatments) for numbers of grade A potatoes. The total numbers of potatoes for 'Atlantic' and 'Frito-Lay 795' cultivars as influenced by flower removal and row cover treatments showed significant interactions of row covers × varieties and varieties × flower treatments. Yield of grade A potatoes for both cultivars as influenced by flower removal and row cover treatments showed a significant interaction between row covers × varieties. Genetic differences occurred among potato cultivars in response to flower removal. cultivar response to row covers were also different based on genetic makeup. Clear and spunbonded polyester were superior to other types of row covers for grade A numbers and yield of potatoes.
Heather H. Friend and Dennis R. Decoteau
Alterations in spectral distribution as affected by selective light transmission of row cover materials were evaluated for effects on early watermelon (Citrullus lanatus cv. Sugar Baby) growth and development. Selected commercially available row covers were analyzed for light transmission properties. Results suggest that row cover materials function as selective light filters and influence parameters of light that can affect plant morphogenesis. Clear polyethylene row covers caused little variation in transmitted PAR (photosynthetically active radiation) and photomorphogenic light (FR/R and blue light). White polyethylene row covers decreased the transmitted PAR and blue light but had no effect on the FR/R ratio. Watermelon plants grown under a white polyethylene row cover with a greater FR/R ratio of light were taller (longer stems) and had longer petioles than plants grown under a clear polyethylene row cover with a smaller transmitted FR/R ratio.
Mack A. Wilson, Michael T. Aide, and Victor A. Khan
Four row covers were evaluated on fall production of `Packman' broccoli and `Gourmet' cabbage at Cape Girardeau, Missouri. Row covers used were spunbonded polyester, insolar and clear slitted polyethylene and VisPore. The mean afternoon soil temperature for row covers were higher than the bare soil control. There were no significant differences among treatments with respect to head size, total numbers and yield of marketable broccoli. The number of broccoli heads per thousand between the bare soil control vs. row cover treatments were significantly different. Data for number of broccoli heads per thousand and marketable yield (Kg/Ha) were significant among row covers. Marketable yield (Kg/Ha) was significant among row covers for `Gourmet' cabbage.
Mack A. Wilson, Victor A. Khan, and Clauzell Stevens
Several plastic mulches [clear, black, IRT-76 (green), and ALOR (brown)] were used in combination with four row covers [(clear and white slitted), spunbonded polyester and VisPore]. The total numbers and marketable numbers per 1000/ha were highest with the clear and IRT-76 mulches without the use of row covers, respectively. There was a significant orthagonal comparison interaction with the clear & IRT-76 mulches vs. black & ALOR mulches. A significant orthogonal comparison interaction was observed with total yield with row covers vs. no row cover, mulch vs. control, clear and IRT-76 vs. black & ALOR, clear vs. IRT-76, and black vs. ALOR. Marketable yield showed a significant interaction with orthogonal comparison with row covers vs. no row cover and clear & IRT-76 vs. black & ALOR.
Matthew T. Rulevich, Francis X. Mangan, and Anne K. Carter
Field studies were conducted in 1998 and 1999 in Massachusetts to assess the effects of transplants, black polyethylene mulch, and polyester spun-bonded row cover on early fruit set and total yield of two squash (Cucurbita moschata Duchesne) cultivars: `C42 × La Segunda' calabaza and `Waltham' butternut. Treatment comparisons included direct-seeded or transplanted squash, with or without black polyethylene mulch, and with or without the addition of a row cover in all combinations. The use of transplants was more effective at stimulating early fruit set and highest total yield than the use of mulch and row cover. The initiation of fruit set using transplants was advanced 9 days relative to direct-seeding. Mulch and row cover treatments significantly advanced early fruit set by 7 and 5 days, respectively, but only in 1998. Yields for both winter squash were 45% higher using transplants compared to direct seeding, 19% higher using mulch compared to bare soil, and 16% higher using row cover compared to no row cover. Total yields were higher for both cultivars in 1999 (warm, dry season) than in 1998 (cool, wet season). Use of transplants with plastic and row cover compared to the use of direct seed with neither plastic nor row cover increased yield of calabaza by 100% in both 1998 and 1999. Only the direct seeded plus plastic plus row cover treatment had yields that were similar to any of the transplanted treatments. Transplant treatments also increased number of fruit per plant and fruit size for both calabaza and butternut.