Jianling FanWeixin Ding Zengming Chen Noura Ziadi. Thirty-year amendment of horse manure and chemical fertilizer on the availability of micronutrients at the aggregate scale in black soil. Environ Sci Pollut Res 2012 19: 2745–2754.
Abstract
Purpose This study evaluates manure and chemical fertilizer effects on micronutrient (Fe Mn Cu and Zn) content and availability in crops.
Methods Seven treatments were selected including three conventional fertilization treatments (NP horse manure (M) and NP plus M (NPM)) three corresponding double rate fertilization (N2P2 M2 and N2P2M2) and a CK. Soil samples were collected and separated into four aggregates by wet-sieving in September 2009. Corn samples were collected and analyzed simultaneously.
Results Treatment N2P2 increased DTPA extractable Fe Mn and Cu in soil by 732% 388% and 42% whereas M2 decreased the corresponding values by 26% 22% and 10% respectively compared to CK. DTPA extractable Zn in soil and Zn in corn grain were higher in the M and M2 treatments than in the other treatments and DTPA Zn was significantly correlated with soil organic carbon (SOC) in large macroaggregate microaggregate and silt + clay fractions. The Mn concentrations in corn stalks and grain were significantly correlated with DTPA extractable Mn in bulk
soil and microaggregates and Zn in stalks were significantly correlated with DTPA Zn in bulk soil microaggregates and large macroaggregates.
Conclusions Long-term application of horse manure could increase soil Zn availability and uptake by corn possibly due to its activation by SOC. In contrast chemical fertilizer application increased DTPA extractable Fe Mn and Cu in soil by reducing soil pH. Our results also suggest that Mn uptake by corn originated mainly in microaggregates whereas Zn in crops was primarily sourced from large macroaggregates and microaggregates.
