Back A. D. Paschoal1, S. K. Homma2, M. J. A. Jorge2 and M. C. S. Nogueira1
Luiz de Queiroz College of Agriculture, University of Sao Paulo, Piracicaba, SP, Brazil1 and
Mokich Okada Foundation, Ipeuna, SP, Brazil2
Full Paper (PDF File: 208KB)
Abstract
To test the effects of Effective Microorganisms (EM) on soil and on natural cycling of nutrients, a field investigation was conducted with citrus in the State of Sao Paulo, Brazil. A Typic Hapludox soil predominates as a deep, well-drained, clay soil with high hydrogen and aluminum contents and low base saturation, The organic matter content of the soil is moderate, i.e., about 21 g kg-1. Tested sweet orange trees were of the Pera variety (Citrus sinensis Osbeck) grafted on Cravo lemon (Citrus limonia Osbeck) rootstock. The design used in this experiment was a Randomized Complete Block Design with 4 replicates for each of the following treatments: 1) control (C), 2) EM applied to soil (EMS), 3) EM applied to citrus plants (EMP), and 4) EM applied to soil and to citrus plants (EMPS). The EM culture used in the experiment was a modified mixture of the three basic cultures, and was sprayed once every 2 weeks. Data presented here are for one season, from March 4 to June 22, 1993, with a total of five applications.
Analyses of the chemical characteristics of the soil and citrus leaves
indicate: 1) a significant (P<0.05) increase in the organic matter content
of the soils treated with EM at both the 0-20 cm and 20-40 cm depths can
be attributed to EM's humus forming capacity from dead grass mulch; 2)
a significant (P<0.01) increase in soil pH at both sampled depths in
the EM-treated lots is an indication that EM alone can change soil reactions;
3) a significant (P<0.05) increase in soil CEC at both depths in the
plots treated with EM can be related to the enhanced soil organic matter
formation; and 4) no statistical differences for any of the other chemical
parameters in the soil or for the macro- and micronuinents in citrus leaves
was found.
No statistically significant differences were found for the physical conditions of the soil, a fact that was almost expected because of the time necessary for full establishment of the microorganisms. Soil compaction tended, however, to be less pronounced for EM-treated plots than for the control.