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|Title:||Changes in soil carbon and nitrogen dynamics during a three year crop rotation on a chernozem soil in the Ukraine|
|Authors:||Medinets, Sergiy V.|
Skiba, U. M.
Medinets, Volodymyr I.
Bilanchyn, Yaroslav M.
Pitsyk, Vasyl Z.
Goshurenko, L. M.
Kotogura, S. S.
Біланчин, Ярослав Михайлович
Биланчин, Ярослав Михайлович
|Citation:||Вісник Одеського національного університету. Сер. Географічні та геологічні науки.- 2014. – Т19, №2 (21) C. 143-165.|
|Keywords:||nitrogen, carbon, nitrate, ammonium, mineralization, nitrification, soil or¬ganic matter|
|Abstract:||Soils in the southern Ukraine have been reported to have lost 32% to 40%, or 51 to 71 t ha-1 of their original soil organic matter (SOM) pool between 1881-1981, mainly due to inap¬propriate soil management by collective farms during 1930-1981. In this period agricultural management was directed towards irresponsible expansion of arable fields and short-term yield increases. Modern, sustainable agricultural management is slowly being introduced. There is a need to assess to what extend such methods stabilize and build new SOM to sup¬port and increase fertility both in the short and long-term. This study investigates the influ¬ence of a modern crop rotation (onion-tomato-barley) on one field, which was tilled, fertil¬ized, irrigated and harvested in response to the crops needs, on the dynamics of total organic carbon (TOC) and total nitrogen (TN) storage in the fertile topsoil of a Chernozem typical for southern Ukraine. Crop residue remained on the field. The results of three years (2007-2009) of quarterly monitoring of the key topsoil parameters TOC, TN, extractable mineral N (NH4+, NO3-, NO2-), pH, potential net N mineralisation (MIN) and nitrification (NITR) rates and physical characteristics (bulk density, soil texture) are discussed. Moderate (114 kg N ha-1 yr-1) and low (28 kg N ha-1 yr-1) N fertilizer applications together with adequate drip irrigation for onion and tomato and incorporation of plant residue did significantly change the C and N pools. Total organic carbon and TN contents of the topsoil horizon (0-74 cm) were found to increase by 20% (26.8 t C ha-1) and 38% (5.9 t N ha-1), respectively. Largest increases were measured in the surface layer (0-27 cm) with a 45% increase in TOC and a 36% increase in TN content. The largest average soil NH4+ content of the topsoil horizon (0-74 cm) was observed in 2009 under barley (154.9±41.3 kg N ha-1) and the maximum average NO3- content was 166.9±44.5 kg N ha-1 under tomato in 2008. Mineralisation and nitrification rates significantly varied between years and with season and were largest in the first year of the crop rotation (onion), 41.0±57.3 kg N ha-1 and 36.6±74.4 kg N ha-1 for MIN and NITR, respectively. The incorporation of plant residues and efficient N fertilizer applications within a crop rotation appeared to be effective in stabilizing the existing SOM and promoting SOM build-up.|
|Appears in Collections:||Статті та доповіді РЦІМПСЕД|
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