Saline water and municipal solid waste compost application on tomato crop: Effects on plant and soil

A field experiment was conducted in Southern Italy to evaluate the effects of different water quality and fertilizers on yield performance of tomato crop. In mineral nitrogen (N) fertilizer and irrigation with fresh water (Electrical Conductivity, EC, = 0.9 dS m(-1)) (FWF); mineral N fertilizer and irrigation with saline water (EC = 6.0 dS m(-1)) (SWF); municipal solid waste (MSW) compost and irrigation with fresh water (EC = 0.9 dS m(-1)) (FWC); MSW compost and irrigation with saline water (EC = 6.0 dS m(-1)) (SWC). At harvest, weight and number of fruits and refractometric index (degrees Brix) were measured, total and marketable yield and dry matter of fruit were calculated. The results indicated that MSW compost, applied as amendment, could substitute the mineral fertilizer. In fact, in the treatments based on compost application, the tomato average marketable yield increased by 9% compared with treatments with mineral fertilizer. The marketable yield in the SWF and SWC treatments (with an average soil EC in two years to about 3.5dS m(-1)) decreased respectively of 20and 10%, in respect to fresh water treatments. At the end of the experiment, application of compost significantly decreased the sodium absorption rate (SAR) of SWC treatment in respect of SWF (-29.9%). Significant differences were observed among the four treatments both on soil solution cations either exchangeable cations. In particular compost application increased the calcium (Ca) and potassium (K) contents in saturated soil paste respect to the SWF ones (31.4% and 59.5%, respectively). At the same time saturated soil paste sodium (Na) in SWC treatment recorded a decrease of 17.4% compared to SWF.