ABSTRACT:
The use of organic wastes as components of substrate on the production of vegetable seedlings allows to obtain alternative materials, easily available and with low cost. We evaluated the effect of substrate conditioners on the quality of organic seedlings and the effect of these seedlings on the yield of lettuce in organic system. The experimental design was randomized blocks with six treatments and four replications. Treatments consisted of the organic substrates carbonized rice husk (T1), coconut shell fiber (T2), organic compost (T3), commercial substrate Golden(r) used as control treatment (T4); chopped palm stipe (T5) and decomposed kapok stem (T6). The cultivar used (Vera) is characterized by curly and loose leaves with light green color adapted to hot weather. An experiment was carried out in a greenhouse and another in the field, both following the randomized blocks design, with four replications, and the experimental unit of 10 seedlings in the greenhouse and six plants in the field, from March to April 2013, under protected environment in Rio Branco, Acre State, Brazil. At 24 days after sowing, we evaluated the seedling quality index (IQD), dry mass of aboveground part and roots of the seedlings. In the field experiment, 45 days after transplanting, we evaluated the dry mass of the aboveground part, marketable fresh weight and yield of the plants. The substrate containing chopped palm stipe as conditioner produced seedlings with the highest quality, followed by carbonized rice husk, coconut shell fiber, organic compost, and decomposed kapok stem with no difference among them. The substrates containing carbonized rice husk, coconut shell fiber, decomposed kapok stem and chopped palm stipe provided greater marketable fresh weight (220; 230; 207 and 208 g/plant, respectively), dry weight of aboveground part and yield (2.44; 2.56; 2.30 and 2.31 kg/m2, respectively) on the organic production system. Thus, alternating those substrates is possible, without loss of productivity.
Keywords:
Lactuca sativa; vegetable propagation; organic agriculture.
