Ca. Grant et Gp. Lafond, THE EFFECTS OF TILLAGE SYSTEMS AND CROP ROTATIONS ON SOIL CHEMICAL-PROPERTIES OF A BLACK CHERNOZEMIC SOIL, Canadian Journal of Soil Science, 74(3), 1994, pp. 301-306
The effects of zero (ZT), minimum (MT) and conventional tillage (CT) s
ystems and three 4-yr crop rotations on soil total C and N, mineraliza
ble N, NO3-N, P, K and SO4-S accumulation and distribution in the soil
profile were determined after one 4-yr cycle of crop production on Bl
ack Chernozemic Indian Head heavy clay soil. The distributions of avai
lable P and K in the profile were not affected by tillage or rotation.
Total C and N in the 0-5 cm depth was higher in the reduced tillage s
ystems than in CT, but differences in the 5-10 cm and 10-15 cm depths
were not significant. Nitrate concentration was higher in the 15-30 cm
and 30-60 cm depths under CT than under reduced tillage. Inclusion of
fallow increased accumulation of NO3-N in the deeper soil depths, whi
le inclusion of winter wheat in the rotation reduced deep movement of
NO3-N. Nitrate-nitrogen accumulation after field pea production was co
mparable to that after winter wheat, but a greater proportion of the N
O3-N was present near the soil surface after winter wheat, reducing th
e potential for leaching below the rooting zone. Potential for movemen
t of NO3-N below the rooting zone may be increased by fallow and decre
ased by production of winter wheat and by reduced tillage systems.