1995 * VI * 4

CONTENTS

SCIENTIFIC WORK
H. Kärblane, L. Kevvai. Contents of heavy metals in the more commonly used fertilizers in Estonia and their contribution to soil pollution ... 393
K. Kask. Estonian apple cultivars ... 405
L. Murdam, M. Metsur, N. Vardjas, I. Maalmann. The geomicrobiology of soil and subsoil under irrigated grassland and under natural plant associations ... 417
A. Reintam. Research into the working process of the spreading disk of a fertilizer spreader using mathematical modelling ... 435
A. Lember. The protein requirement of the sows during the reproductive cycle. 2. The influence of protein content in the ration during lactation on the reproductive performance of sows ... 449