Maximiliano Martínez1 y Elías Letelier A.1
Results of a permanent trial on monoculture with wheat, initiated in 1963/1964, are presented. Four rates of fertilization are being tested with the monoculture, one of them being zero fertilization. Since 1967/1g68, one of the replications is being desinfes- ted annually with methyl bromide.
The results indicate:
- An initial depresive effect of monoculture, lasting 4 years.
- A subsequent gradtial recovery of the yields of the monoculture (not desinfested) up to rather good yields in the last years, provided that fertilization is applied.
- A large positive effect on yields of soil desinfesta tion; these yields continue at a high level, provided that fertilization is applied.
- A continuous fall of yields in the treatment desin fested but not fertilized. Explanations for these results are proposed.
1 Ings. Agrs., Programa Ecología y Manejo, Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias (INIA), Casilla 5427, Santiago, Chile.