CHANGES IN SOIL TEMPERATURE AFFECTED BY THE APPLICATION OF PLASTIC COVERS IN FIELD PRODUCTION OF LETTUCE AND WATER MELON

In the period 1991–1992 the effect of low tunnels, perforated plastic sheeting, and unwoven fabric on thermal conditions and some qualitative traits of crop was investigated in lettuce and watermelon cultivation.
In the case of watermelon black PE mulch was additionally used.
At 8.00 a.m. the highest soil temperature was found in low tunnel.
In the period of early spring (March 29-April 14) it exceeded that in open ground by 3.0°C and in late spring (June 4–19) by 5.9°C. At 2.00 p.m. the highest temperature was noted under a perforated plastic cover, differences amounting to 5.1 and 6.8°C, respectively, in relation to the open ground.
In the period of watermelon growing high soil temperatures under the perforated sheeting and in the low tunnel were accompanied by outdoor air temperatures reaching 40°C. The highest marketable yield of lettuce was obtained from the low tunnel.
It exceeded that from open ground by 110.9%. The highest marketable yield of water- melon (an increase by 263.6%) was obtained from plots covered with unwoven fabric.
Of the qualitative traits of the crop a much greater content of L-ascorbic acid and dry matter was found in lettuce grown without the covers, while in watermelon grown in the tunnel an in non-covered plots the amounts of dry matter and total sugars were smaller.

VII International Symposium on Timing Field Production of Vegetables

A. Libik, P. Siwek

plastic covers, lettuce, watermelon, temperature

https://doi.org/10.17660/ActaHortic.1994.371.34