Long term effects of soil organic amendment or mineral fertilization on vegetable crops productivity in tunnel

In Pontecagnano (Piana del Sele, Salerno), four fertilization treatments were applied in different times under tunnel: 1) Organic amendment A, 2) Mineral fertilization (since July 1995); 3) Organic amendment B, 4) Not treated Control (since July 1997). The same vegetable crop sequence was effectuated in all the treatments: tomato (Lycopersicon esculentum) – zucchini (Cucurbita pepo) in 1995-1997; grafted eggplant (Solanum melongena) in 1998-1999; pepper (Capsicum annuum) in 2000; muskmelon (Cucumis melo) in 2001. Organic amendment A was fertilized with an initial high amount (400 t ha-1) of worm-casting in 1995. Successively, in July 1997, another kind of worm-casting was applied in rates of 70 and 140 t ha-1 in Organic amendment A and Organic amendment B treatments, respectively. According to the same criterion, 17 and 34 t ha-1 of compost were rototilled before pepper transplant (March 2000), whereas in March 2001 (before melon transplant) were rototilled 17 and 34 t ha-1 of cow manure + 50 t ha-1 by a cover crop of Raphanus sativus ‘Boss’. Soil organic matter content changed drastically in Organic amendment A units. In 1996, it was 5.7 %, over 1 % in comparison with the Control and Mineral treatments. In the Organic amendment B, on the contrary, organic matter content has been increasing since 1997 and it nearly reached 5 % threshold in November 2000. Productive results of the bell pepper cultivation point out a significative difference among organic amendment treatments and Control or Mineral ones (in average + 123 % and + 73 %, respectively). Statistical analysis does not point out any difference due to the treatments in the next cultivation cycle of muskmelon. It’s evident, however, that yield trend was the same recorded in the pepper trial. Average yield of the organic amendment treatments showed an increase of 116 % and 65 % compared with Control and Mineral ones.