Principles of Conservation Agriculture in Continental Steppe Regions

Abstract

In western Siberia, summer fallow-based crop rotation is practiced. These tillage-based cropping systems are not sustainable. They lead to a decline in soil fertility and damage to humans and the environment. The objective of this chapter is to analyze the principles of conservation agriculture (CA) and to replace wheat-fallow monocultures by stubble mulch farming. We conducted multi-factorial field experiments on crop rotations, tillage, and soil fertility management on three sites over more than five years. The research data include the results of studies in northern Kazakhstan, central Kazakhstan, and western Siberia. Furthermore, we analyzed results from other cool steppe regions such as Canada. In studies conducted in northern Kazakhstan, we found that cropland is most efficiently used in diversified crop rotations with no fallow. Summer fallow can be replaced by food legumes or legume forages. No-till has an advantage in terms of crop yields over traditional tillage on light textured soils of the Kostanai province, thanks to better moisture conservation. On heavy textured soils of the Akmola province, traditional tillage has an advantage in some cases, thanks to better snowmelt water intake and more active nitrogen mineralization. On Leached Chernozems of Trans-Ural Siberia, no-till is feasible only with the application of higher rates of nitrogen fertilizer. In the forest-steppe zone of western Siberia, no-till in the autumn provided the same grain yields as ploughing only when it was combined with the application of fertilizers, herbicides, fungicides, and growth regulators. Research in northern Kazakhstan shows that for soil fertility conservation, one should combine a reduced to minimum area under summer fallow with the replacement of summer fallow by pulses or legume forages and the application of nitrogen fertilizer, and thus avoid soil tillage.