Vaderstad RAPID RD F Series, Instructions Manual

Page: 75 / 114

RD 300-450 F
Ver.1.3 07/06/01 75
4.16 Cultivating silty soils
4.16.1 Spring sowing on silty soils
Silty soils are very slow to dry out and warm up in the spring. This is mainly due to the excellent
capacity of these soils for capillary transport of water to the surface. Autumn ploughed silty soils
have time to consolidate during the winter and this produces the continuity of pores which creates
good capillarity and resultant slow surface drying in the spring.
Results indicate that spring ploughing is better than autumn ploughing on silty soils. This is be-
cause spring ploughing can temporarily interrupt capillary transport of water. Some excess water
has also been removed and some warmth incorporated into the soil.
The motto on silty soils is: shallow sowing in a warm fine seedbed, after a spring cultivation
such as ploughing to break capillary transport. The important point is to loosen the silty soil
to some depth in spring. This helps root development, gets some heat into the soil and allows any
subsequent pan formation to be dealt with.
Shallow placement of the seed is important on silty soils to ensure rapid emergence before a sur-
face pan can form and to produce more robust seedlings. A robust seedling is more likely to sur-
vive pan formation.
On silty soils, it is often possible to Rapid drill directly after cultivating or ploughing. Use the tool
bar!
4.16.2 Ploughless tillage - a possibility for silty clays
An interesting method is to increase the humus content and aggregate stability of the surface layer
by systematic shallow incorporation of straw, farmyard manure or even green manure, while re-
placing the plough by shallow cultivation to 15 cm.
The following conditions should be met for successful ploughless tillage:
! Good wheel equipment on all heavy machinery
! Effective stubble treatment equipment
! A means of dealing with couch-grass within the crop rotation
! A suitable crop rotation, preferably including green manure
! Effective straw disposal in autumn, short stubble after combining or stubble trimming.
! A drill which can handle shallow sowing into a very trashy seedbed.