Characterization Of Different Compost For Use As Component Of Substrates

The use of substrates in agriculture has increased in recent years. Compost is one of the materials used in substrate formulation, and therefore, it is important to know its properties prior to its use. The objective of this study was to characterize 15 different types of compost from different sources in order to evaluate them as substrate components. The following parameters were determined: bulk density, total pore space, water retention capacity (CR A), aeration porosity (PA), granulometry, pH, electrical conductivity (EC), and concentrations of calcium, magnesium, potassium, sodium and nitrates. There were significant differences (P < 0.0001) among the compost for all the variables analyzed. Poultry compost had the highest bulk density. Thick pine bark compost had the highest percentage of PA, while pruning waste compost recorded the highest percentage of CR A . Pine bark compost could increase aeration in a substrate formulation. The pH values obtained ranged from 4.7 to 8.7, while CE values varied between 0.09 and 5.55 dS m(-1). Most of the compost exceeded an optimal pH range (5.5-6.3). On the contrary, most compost did not reach high EC values. However, some types of compost, such as those from poultry, urban solid waste and pig waste, exceeded 1 dS m(-1), and could cause harmful effects on plants. All types of compost are viable for use provided both compost properties and crop conditions are considered to decide which substrate to use.