Time filter

Source Type

Soares I.A.A.,Rural University | Freitas F.C.L.,Dep. de Ciencias Vegetais | Negreiros M.Z.,Dep. de Ciencias Vegetais | Freire G.M.,UFERSA | And 4 more authors.
Planta Daninha | Year: 2010

This work aimed to evaluate weed interference in yield and quality of carrots (Daucus carota). An experiment was carried out in a randomized block design, with four replications. The treatments were composed of six periods of weed control (0-12, 0-24, 0-36, 0-48, 0-60 and 0-72 days after emergence (DAE)). The characteristics evaluated were: yield of commercial roots, total soluble solids (TSS), total titratable acidity (TTA), vitamin C, TSS/TTA ratio and pH of roots. The commercial root yields decreased with weed interference, with weed control being required until 36 DAE. Root TSS rates and vitamin C did not vary with weed interference. The presence of weeds for a longer period increased pH and TSS and decreased TSS/TTA ratios.

Teofilo T.M.S.,Agricola Famosa | Freitas F.C.L.,Dep. de Ciencias Vegetais | Medeiros J.F.,Dep. de Ciencias Ambientais | Fernandes D.,Fitotecnia | And 3 more authors.
Planta Daninha | Year: 2012

The objective of this work was to evaluate the effect of the conventional and no-tillage systems and weed management strategies on water use efficiency in melon crop (Cucumis melo). Thus, an experiment was carried out in a randomized block design in split-plots in Mossoró-RN. The plots were constituted of two tillage systems (conventional and no-tillage) and the sub-plots of three weed management systems (plastic mulch, weeding, and no weeding). Density and dry weight of the weeds at 30 days after transplanting, commercial and total yield and daily consumption of water were evaluated. Irrigation management was performed by the characteristic soil water curve for each cropping system at 15 and 30 cm of depth and water control by daily reading a set of tensiometers installed to keep the soil above 75% of field capacity. Water use efficiency (USA), given in kg of fruit per m3, was determined based on the crop's yield and water consumption. It was found that the no-tillage system reduced weed density and dry matter in 86.7 and 61%, respectively, compared to conventional tillage, and weed interference reduced commercial yield by 100% under conventional tillage and 36.5% under no-tillage. Soil with plastic mulch under no-tillage and conventional systems, and straw mulching under no-tillage reduced water consumption by 23% (388.8 m3 ha-1), 21% (363.0 m3 ha-1) and 13% (215.0 m3 ha-1), respectively, compared to the weeding treatment under conventional tillage. Soil with plastic mulch under the two tillage systems, or straw mulching under no-tillage increased the efficiency of water use from the ground without cover. In the no-weeding treatment under conventional tillage, weed interference caused total productivity loss and increased water consumption by 9.6%.

Loading Dep. de Ciencias Vegetais collaborators
Loading Dep. de Ciencias Vegetais collaborators