EFFECTS OF THE USE OF FLOATING ROW COVERS ON ENVIRONMENTAL VARIABLES AND CROP YIELD LETTUCE

Abstract

This study aims to evaluate the effect of protecting floating row covers on the behavior of environmental variables and the yield of a crop of lettuce. For it was sowed during two seasons autumn-winter cultivar of butterhead lettuce type (Lactuca sativa var. capitata) in germination trays of 128 cells with subsequent transplantation field performed at 37 (cycle 1) and 49 (cycle 2) days after sowing. The treatments were: 1)- Crop protected with floating row cover (MT); 2)- Control unprotected (T) in an experimental design in split plots with 3 repetitions. The plantation frame used was 0.35 m between rows and 0.25 m between plants and irrigation was made by a drip system. The effect of floating row cover on the transmissivity of photosynthetically active radiation (PAR), temperature and relative humidity, crop yield, heat summation in degree.days-1 from trasplant to harvest (ºC.ddt-1) and efficiency of use of radiation (EUR) was evaluated. The results showed an average transmissivity of 63.1% RFA, temperature increase of minimum, average and maximum air 1.1; 2.0 and 3.1 °C respectively, and 4.3% relative humidity. The fresh weight yield (t ha-1) showed statistically significant differences between treatments, being 38.2 (MT); 15.5 (T) for cycle 1 and 33.8 (MT) and 14.7 (T) for cycle 2. The heat summation and EUR was higher in the treatment with floating row cover. Crop protection allows greater earlier maturity with significant performance improvements.