Fertilization and tillage effects on soil properties and maize yield in a southern pampas Argiudol

WYNGAARD, N.; ECHEVERRIA, H.E.; SAINZ ROZAS, H.R.; DIVITO, G.A.

SOIL & TILLAGE RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012

0167-1987

Agricultural management practices, such as tillage and fertilization alter soil physical, chemical andbiological properties over the medium term, which has a direct impact on the systems sustainability andcrop performance. The aim of this work was to evaluate how fertilization with nitrogen (N), phosphorus(P), sulphur (S), micronutrients (Mi), liming (Li) and tillage systems affect soil properties in the mediumterm, and to measure the impact of these changes on maize (Zea mays L.) yield.A seven-year experiment on a Typic Argiudoll in the Southern Pampas region of Argentina using sevenfertilizations treatments (Control, N P, NS, PS, NPS, NPS + Mi, and NPS + Mi + Li) and two tillage systems: conventional tillage (CT) and no-till (NT) were evaluated. Each sub-plot was analyzed to determinephysical parameters -bulk density (BD) and aggregate stability (AS)-, biological parameters - total organic carbon (TOC), carbon in the particulate fraction (COP), anaerobically incubated nitrogen (AN),total nitrogen (TN) and nitrogen in the particulate fraction (PN)-, and chemical parameters - nitrate,available phosphorus, sulphate and pH-  at different depths. Also, maize yield was measured in the finalyear without fertilizer application, in order to evaluate the effects of soil changes on this crop.Among the physical parameters, the only differences found were in BD between tillage systems in the0-5 cm layer (1.28 g cm3 in NT and 1.15 g cm3 in CT). Biological parameters were unaffected byfertilization treatments. However, tillage systems modified many of them in the 0?5 cm layer: COT(17 Mg ha-1 in CT and 21 Mg ha-1 in NT), POC (2.4 Mg ha-1 in CT and 4.5 Mg ha-1 in NT), TN(1.4 Mg ha-1 in CT and 1.8 Mg ha-1 in NT), PN (0.3 Mg ha-1 in CT and 0.5 Mg ha-1 in NT) and AN(56 mg kg-1 in CT and 79 mg kg-1 in NT). These differences were not significant when the 5?20 cm depthwas analyzed. Chemical properties such as pH (5.7 in treatments with N; 6.1 without N, and 6.4 with Nand lime) and P Bray content were modified (35 mg kg-1 in treatments with P and 13 mg kg-1 withoutP). In both cases, there was interaction with the tillage system, with significant stratification under NT.Maize yield was only affected by residual P; there were no other effects of medium-term fertilizationor tillage systems.