Production of lettuce under different fertilisation treatments, yield and quality.

摘要

Lettuce cultivars Gallega and Mantecosa were grown in Buenos Aires, Argentina field during the autumn and winter seasons [date not given], to study the effects of organic and inorganic fertilizers on the production and contents of nitrates and vitamin C [ascorbic acid]. Four fertilizer treatments were applied: two organic (vermicompost and biostabilized compost) and two inorganic ones (94% Ca (NO3)2+6% NH4NO3 and 74% Ca (NO3)2+6% NH4NO3+20% urea), and a control without any added fertilizer. Yield,vitamin C, nitrate and dry matter were determined at commercial maturity stage. Mantecosa showed significant differences for yield and nitrates content and no significant differences for dry matter and vitamin C among treatments. The 74-6-20 and the vermicompost treatments resulted in the largest yield. The 94-6 treatment showed the highest nitrate content; whereas, the control and the biostabilized compost had the lowest nitrate content. The mineral fertilizer treatments had a lower level of vitamin Ccompared to organic treatments. An opposite trend seemed to be valid for the nitrate concentration. Gallega presented two groups with significant differences for nitrates. The 94-6 treatment presented the largest concentration and vermicompost the lowest. Yield was only significant with regard to control. Vermicompost and 74-6-20 treatments obtained the largest yields. No significant differences were observed for vitamin C concentration. Comparing the two cultivars Mantecosa presented a larger nitrate concentration (2040 mg/kg fresh weight, FW). The vitamin C contents were high (23 and 19 mg/100g FW) in both cultivars. Concerning the applied fertilization, vermicompost presented the best result, i.e. a high yield, a low nitrate content and a high vitamin C content.