Prediction of organic matter content based on soil colour

Organska tvar tla (OTT) ima ključnu ulogu u agroekosustavima. Smanjenje njenog sadržaja zbog promjene korištenja zemljišta može negativno utjecati na okoliš. U skladu s tim, sadržaj OTT redovito se analizira u laboratoriju. Kako su te analize skupe i dugotrajne, testiraju se i one neizravne. Cilj rada bio je ispitati mogućnost predviđanja sadržaja OTT linearnom regresijom s bojom tla kao prediktorom. Tla su uzorkovana u blizini Agronomskog fakulteta u Zagrebu. Po pet uzoraka površinskog sloja tla u ponavljanju uzeto je na poljoprivrednom zemljištu, na livadi, te u šumi. Boja tla određena je Munsell-ovim sustavom. Tla su bila vrlo kisele do neutralne praškaste ilovače. Sadržaj OTT kretao se od niskog do visokog. Boja tla u suhom stanju dominatno je bila svijetlo žućkasto smeđa i svijetlo maslinasto smeđa. Sadržaj OTT mogao se predvidjeti temeljem chrome suhih uzoraka (R2 = 0,876). Buduća istraživanja trebaju obuhvatiti više uzoraka, uzetih sa šireg područja i iz više različitih tala.Soil organic matter (SOM) has crucial roles in agroecosystems. Decline in its content, as a result of land use change, can have a negative impact on environment. Accordingly, SOM content is regularly analyzed in the laboratory. As such analyses are expensive and time consuming, indirect methods are tested. Aim of this study was to examine the possibility of predicting SOM content using linear regression, with soil color as predictor. Soils were sampled near the Faculty of Agriculture in Zagreb. Five replicate topsoil samples were taken on agricultural land, five on a meadow, and five in a forest. Soil color was determined using the Munsell system. Soils were very acidic to neutral silt loams. Their SOM content ranged from low to high. Dry soil colors were light yellowish/olive brown. It was found possible to predict SOM content based on dry soil chroma (R2=0.876). Future studies should involve a larger number of soil samples, taken from a wider area and across several different soils