Nitrogen conservation in soil and crop residues as affected by crop rotation and soil disturbance under Mediterranean conditions

Abstract

We investigated conservation and cycling of N under oat-oat and lupine-oat rotations in disturbed and undisturbed soil, when roots or roots plus aboveground residues were retained. Crop residues were labelled with 15 N in Year 1, and differential soil disturbance was imposed after harvest. In Year 2, plant growth, N transfer from residue into the various sinks of the second crop (plant, soil, and residual residues), and changes in microbial activity and numbers were determined. Oat biomass was greater after lupine than after oat due to differences in supply of N from these residues. Buried residues of both crops appeared to decompose faster than when left on the soil surface. Lupine residues decomposed faster than oat residues. Oat biomass was not affected by soil disturbance if grown after lupine but decreased when oat straw was buried in the soil. More residue N was recovered from soil than from the crop. for oat and 61-63 kg N ha −1 for lupine relative to treatments where they were removed. Over a year, lupine contributed 9 to 20 kg N ha −1 more to the agroecosystem than did oat.

Crop residue effect on crop performance, soil N2O and CO2 emissions in alley cropping systems in subtropical China

“…Amilcar) through their decomposition cycle (Ordóñez et al 2007). Similarly, Varennes et al (2007) found that oat biomass production was greater after lupine than after oat. They attributed this to a fact that lupine residues decomposed faster and sustained a great microbial activity, and in turn enhanced subsequent plant growth by providing more N than oat residues.…”

“…Studies have consistently revealed that legumes can increase the yields of subsequent crops, in particular when no fertilizer N was applied (Heenan 1995;Shah et al 2003;Mayer et al 2003;Varennes et al 2007). …”

Effect of Crop Sequences, Crop Residues, Sulfur Application and N-Fertilizer on Wheat Crop Grown on Sandy Calcareous Soils

“…while treatment (sequence 3 + CR) resulted in significant increases in grain, straw and biological yields estimated by 69.1%, 49.7% and 56.2% respectively as compared with continues cereal crops sequence 1 (control). Wheat grain yield of treatment sequence 4 + CR was sig- Varennes et al, (2007). They investigated soil conservation under oat-oat and lupine-oat rotations when roots or roots plus aboveground residues were retained.…”

Soil nitrogen availability in olive orchards after mulching legume cover crop residues

“…In the latter case, a natural source of N must be sought. Legume species, for instance, are able to fix atmospheric N, meeting their own needs and transferring N to a non-legume crop after their N-rich tissues have been mineralized (De Varennes et al, 2007;Russelle, 2008). Legume species can be grown either as main crops in rotation and/or as cover crops or green manures in annual and perennial tree crops.…”