Effect of composts produced from vegetable waste and/or manure on lettuce crop and their antioxidants content

Currently one of the most important problems in the world is the erosion and the low productivity of the agriculture soils, so a common practice to increase yield is to use mineral fertilizers; however excessive use cause environmental problems. The application of composts based on organic wastes is a sustainable way to reduce soil pollution and increase their fertility. The aim of this work was to evaluate the compost effect made from different combinations of vegetable waste and cow manure on the yield and antioxidant content of a lettuce crop, and its comparison with two controls: chemical fertilizers (Chem) and without fertilization (C-). Four types of composts were prepared using vegetable waste (V), stubble (S), cow manure (M) and the mixture of vegetable and cow manure (MV), the fertilization rate was 5 and 10%. The variables evaluated were plant height, number of leaves, foliage volume, and antioxidants content. Composts V and S registered greater height (p>0.05) than the rest of the treatments and controls. There were no differences (p>0.05) in antioxidant content between treatments and controls; however, the composts promoted higher values of DPPH and polyphenol content with respect to C-. The results obtained in the evaluated variables were due materials used for composting, were better with those made with vegetable waste. Composting vegetable residues and animal manure is a good alternative to diminish use of mineral fertilizers and the need of disposing these organic material, since the composts improved the lettuce properties compared to C-.