Changes in agrophysical properties of clay loam soils in relation to different fertilization systems
2001
Kristaponyte, I. (Joniskelis Research Station of the Lithuanian Inst. of Agriculture, Joniskelis (Lithuania))
A high content of physical clay particles and low humus content in clay loam soils result in the manifestation of negative physical properties of the soil. At the Lithuanian Inst. of Agriculture's Joniskelis Research Station trials were carried out over the period 1996-2000 on a Calcari - Hypostagnic - Luvisols, clay loam on silty clay soil, in a five-course crop rotation where we investigated mineral, organic, and organic - mineral fertilisation systems with a view to increasing humus content and improving physical properties of clay soils. The trial involved the following crop rotation: sugar beet, barley undersown with perennial grasses, perennial grasses of the first year of use, perennial grasses of the second year of use, winter wheat. Organic fertilisers 40, 60 and 80 t ha sup(-1) were applied to the member of the first rotation - sugar beet. It was determined that 40, 60 and 80 t ha sup(-1) of farmyard manure together with NPK fertilisers increased humus content in the topsoil by 13,1 - 14,6 - 16,2 per cent respectively. Through fertilisation the soil structurality was 16,7 - 16,9 per cent higher than in unfertilised treatments, its bulk density declined by 6,1-6,1-5,4 per cent, and the total porosity increased by 7,1-8,6-9,1 per cent respectively. Fertilisation with farmyard manure only at a rate of 80 t ha sup(-1) improved soil structure by 12,6 per cent, and reduced bulk density by 5,4 per cent, and increased total porosity by 4,9 per cent. Application of different rates of farmyard manure in the organic - mineral fertilisation systems resulted in 61,2-63,2-63,4 per cent increase in average crop rotation productivity, and in the organic system- 32,2 per cent
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