Quantity and Quality of Soil Organic Matter in Ecological and Integrated Farming System

Abstract

Impact of farming system on the quantity and quality of soil organic matter was studied. The experiment was situated on Haplic Luvisol of Research -experimental base of Slovak University of Agriculture Dolná Malanta, where over a period of 5 years soil samples from ecological (ES) and integrated (IS) farming system were collected. In period of 5 years, on average higher contents of total organic carbon (TOC) and total nitrogen (NT) were in ES (1.219%; 1382 mg.kg ). TOC content in the ES was on the level of variants with application of farmyard manure, while in the IS it was on the level of non-fertilized variants. The highest contents of TOC and non-labile carbon (CNL) were recorded in 2010 when the previous crops were alfalfa (Medicago sativa) and pea (Pisum sativum). Higher content of CNL was in the ES than in the IS. A positive linear relationship between the amounts of precipitation per year and during the vegetation was observed not only between TOC contents (r = 0.914, P < 0.05 and r = 0.971, P < 0.01), but also CNL contents (r = 0.880, P < 0.05 and r = 0.952, P < 0.05). The most stabilized humus substances were in 2007, when the highest average temperature per year and during the vegetation was recorded. In 2010, the lowest amounts of extracted humus substances were recorded, with domination of humic acids. Their stability, however, on the base of colour coefficients of humus substances and humic acids were the lowest from all years. The humus substances were more stabilized in the IS than in the ES. ). Obsah TOC sa v ES pohyboval na úrovni variantov hnojených maštaľným hnojom, kým v IS to bolo približne na úrovni nehnojeného variantu. Najvyššie obsahy TOC a nelabilného uhlíka (CNL) boli zaznamenané v roku 2010, kedy boli predplodinami lucerna siata (Medicago sativa) a hrach siaty (Pisum sativum). Vyšší obsah frakcie CNL bol v ES ako v IS. Pozitívna lineárna závislosť medzi množstvom zrážok za rok ako aj počas vegetácie bola zaznamenaná nielen medzi obsahom TOC (r=0,914; P<0,05 a r=0,971 P<0,01), ale aj CNL (r=0,880; P<0,05 a r=0,952; P<0,05). Najstabilnejšie humusové látky boli v roku 2007, kedy bola zaznamenaná najvyššia priemerná teplota za rok aj za vegetáciu. V roku 2010 boli zaznamenané najnižšie množstvá vyextrahovaných humusových látok, pričom dominovali humínové kyseliny. Ich stabilita však na základe farebných kvocientov humusových látok a humínových kyselín bola najnižšia zo všetkých rokov. V ES boli humusové látky menej stabilizované ako v IS.