The influence of conventional and conservation tillage on content of total and labile soil organic matter

Abstract

In the temperate agro-ecological conditions of Vojvodina province there is a lack of research on the impact of different tillage to the soil organic matter change. Simultaneously, the introduction of conservation tillage systems is expanding, as a viable option for climate friendly agriculture. The aim of this study is to compare the effects of conservation and conventional management in winter wheat and sunflower production on the OM change. The study was performed in Padina (South Banat) on the calcareous chernozem soil. Soil samples were taken from a depth of 0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm. Conventional tillage was done with a plow at a depth of 25 cm for winter wheat, and 27 cm for sunflower, while conservation tillage was carried out with heavy harrows at a depth of 15 cm for winter wheat, and with combined tool Horsch Terrano at a 25 cm depth for sunflower. The total content of OM in the soil was higher in the conservation tillage as compared to plowing. The highest content of OM with conservation tillage was found at adepth of 10-20 cm after sunflower, and 0-10 cm in winter wheat plot. The higher content of labile organic carbon soluble in hot water (HWC) was found in the plowing of winter wheat and sunflower in a plow layer of 0-20 cm, and the lowest content was found at a depth of 20-30 cm. In the conservation tillage higher HWC content for winter wheat was found at the depth of 0-10 cm, and 10-20 cm in sunflower, indicating that crop residue deposition and amount affect the accumulation of OM. Soil depth manifested a higher impact on HWC content in relation to the tillage system and crops. With plowing, Carbon Management Index indicated the OM accumulation at a depth of 20-40 cm in winter wheat, and 0-20 cm in sunflower. Conservation tillage resulted with the OM accumulation in a 20-40 cm soil layer for both crops. The regression analysis showed that with the increase of the labile organic matter fraction, associated with crop residue retention, the total OM could also be preserved.

U agroekološkim uslovima Vojvodine ne postoji dovoljno istraživanja o uticaju različitih načina obrade na dinamiku organske materije u zemljištu. Istovremeno, savremeni načini obrade se sve više zasnivaju na uvođenju mašina za redukovanu obradu zemljišta. Cilj ovog rada je analiza uticaja redukovane i konvencionalne obrade u proizvodnji pšenice i suncokreta na promenu nivoa organske materije. Istraživanje je obavljeno u Padini (Južni Banat) na zemljištu koje pripada tipu černozem. Uzorci zemljišta su uzeti sa dubine od: 0-10 cm, 10-20 cm, 20-30 cm i 30-40 cm. Konvencionalna obrada kod pšenice izvedena je plugom pri dubini od 25 cm, a kod suncokreta na 27 cm, dok je redukovana obrada kod pšenice obavljena teškom tanjiračom na 15 cm, a kod suncokreta kombinovano razrivačkim oruđem Horsch Terano 3 na 25 cm. Ukupan sadržaj organske materije (OM) u zemljištu je bio veći na parcelama na kojima se izvodi redukovana obrada u odnosu na konvencionalnu obradu plugom. Najveći sadržaj OM kod redukovane obrade suncokreta utvrđen je pri dubini od 10-20 cm, a kod pšenice na 0-10 cm. Najveća vrednost labilne organske materije rastvorljive u toploj vodi (HWC) je bila u sistemu oranja kod pšenice i suncokreta u sloju 0-20 cm, a najniža vrednost na dubini od 20-30 cm. Kod redukovane obrade najveća vrednost HWC-a kod pšenice utvrđena je u dubini 0-10 cm, a kod suncokreta 10-20 cm što ukazuje da mesto zaoravanja i količina biljnih ostataka utiču na nakupljanje OM. Veći uticaj na HWC ispoljila je dubina u odnosu na sistem obrade i usev. Analiza Carbon management index-a (CMI) ukazuje na nakupljanje OM konvencionalnog sistema obrade plugom kod pšenice u sloju 20-40 cm, dok je kod suncokreta nakupljanje OM od 0-20 cm. Kod redukovane obrade nakupljanje OM veoma je izraženo u sloju od 20-40 cm kod oba useva, a regresionom analizom je utvrđeno da se sa porastom ukupne OM povećava i sadržaj labile OM.