
A short-term comparison of organic v. conventional agriculture
in a silty loam soil using two organic amendments
J. F. Herencia1, J. C. Ruiz1, S. Melero1, P. A. Garcia Galavís1 and C. Maqueda2*
Summary
The transition from conventional to organic farming is accompanied by
changes in soil chemical properties and processes that could affect
soil fertility. The organic system is very complex and the present work
carries out a short-term comparison of the effects of organic and conventional
agriculture on the chemical properties of a silty loam soil (Xerofluvent)
located in the Guadalquivir River Valley, Seville, Spain, through a
succession of five crop cycles over a 3-year period.
Crop rotation and varieties were compared in a conventional system
using inorganic fertilizer and two organic systems using either plant
compost or manure.
At the end of the study, organic farming management resulted in higher
soil organic carbon (OC), N and available P, K, Fe and Zn. The available
Mn and especially Cu values did not show significant differences.
In general, treatment with manure resulted in more rapid increases
in soil nutrient values than did plant compost, which had an effect
on several crop cycles later.
The present study demonstrated that the use of organic composts results
in an increase in OC and the storage of nutrients, which can provide
long-term fertility benefits. Nevertheless, at least 2–3 years
of organic management are necessary, depending on compost characteristics,
to observe significant differences. Average crop yields were 23% lower
in organic crops. Nevertheless, only two crops showed statistically
significant differences.
Source
Journal of Agricultural Science (2008) 146: 677-687
Author Locations and Affiliations
(1) Centro de Investigación y Formación Agraria ‘Las
Torres-Tomejil’ (CIFA), P.C.41200, Alcalá del Río
(Sevilla), Spain
(2) Instituto de Recursos Naturales y Agrobiología (CSIC), Apdo
1052, P.C. 41080, Sevilla, Spain
* Corresponding Author, Email juanf.herencia@juntadeandalucia.es
en français
Posted December 2008