Long-term Effects of Different Municipal Solid Waste Compost Levels on Some Macronutrient Concentrations in Basil (Ocimum basilicum L.)

In order to evaluate the effect of different municipal solid waste composts (MSWC), either enriched or non-enriched, on some macronutrient concentrations in basil, in 2009, a field experiment was arranged as a split plot based randomized complete block design, with three replications. Main plots consisted of six levels of fertilizer (control, recommended chemical fertilizer or CF as 70, 60 and 50 kg ha-1 of urea, potassium sulphate and superphosphate triple, respectively, MSCW as 20 and 40 ton ha-1 alone or plus ½ CF), and sub plots were four application periods including one (2006), two (2006-2007), three (2006-2008) and four (2006-2009) continuous years of MSWC application. Results showed that there was a highly significant interaction between MSWC and application periods in terms of dry matter yield and N, P and K concentrations. Orthogonal comparisons indicated that all studied traits significantly increased in plant leaf (approximately 14 to 36%) with higher application periods compared to CF. Using 20 ton ha-1 of MSWC for three or four continuous years recorded the highest N and K concentrations. Generally, application of 20 ton ha-1 MSWC, either enriched or non-enriched, dramatically improved the studied traits in the plant leaf, except P concentration.