Determinación del periodo crítico en el cultivo de lechuga (Lactuca sativa L.) variedad winter en competencia con plantas ondeseables

Abstract

The current research proposes determining the critical period in the lettuce crop (Lactuca sativa L.) Winter variety regardind to undesired plants, this research was carried aot in the horticulture Department facilities of Escuela superior Politécnica de Chimborazo, Riobamba County, Chimborazo province, this was carried out usung a completely randomized block design (DBCA) with 9 treatments and 3 repetitions. The 9 treatments resulted from the different control periods which were used. The days in which the weed control was carried out 25,40, 55 and 70 day taking into account the two periods initially full of weed- rest of the clean cycle and initially clean- the rest of the full of weed cycle plus a treatment which remained clean during the whole cycle. There were differences between the weed control period carried out for plant height, number of leaves, strength, equatorial diameter, cabbage weight, and prodution, fresh and dry biomass of weed. The best control period was considered when the crop remained clean during the whole cycle. The most expensive treatment was T9 (whole cycle clean crop) with 8191,31 dollrs, the most net benefit was also obtained with 28.051,2 dollars. The best production was shown wen using T9 (whole cycle clean crop) with 105,97 tons per hectare. The best margin rate of return was presented when going from T9 to ( whole cycle clean crop) to T8 (70-day clean crop and the rest of the full of weed cycle) with 457,52%. It is recomended to eliminate the weed when the crop is in the cabbage stage (38 days after transplanting being this the critical period of competition.

Key words: Lettuce crop, critical period of competition, undesired plants.