Root decomposition at high and low N supply throughout a crop rotation

HERRERA JM, BUCHI L, RUBIO G, TORRES-GUERRERO C,WENDLING M, STAMP P, PELLET D.

EUROPEAN JOURNAL OF AGRONOMY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 84 p. 105 - 112

1161-0301

Soil nitrogen (N) dynamics can be modified by covercrops in rotations with cereals. Although, roots area major source of N, littleis known about the dynamics of root decomposition of cash and cover crops.Theobjective of this study was to assess the effects that cover crop species haveon i) the decompositionof spring wheat roots during the growth of cover crops,and ii) the decomposition of cover crop rootsduring the growing season ofspring wheat. The experiment aimed also at comparing three non-winterhardycover crops of varying shoot C/N ratios under low and high N input levels of 6and 12 g N m−2y−1,respectively.The experiment included spring wheat (Triticum aestivum L.) as themain crop and non-winter hardy cover crops (yellow mustard (Sinapisalba L.), phacelia (Phaceliatanacetifolia Benth), and sunflower (Helianthusannuus L.) as well as bare soil fallow treatment.Minirhizotrons were used to non-destructively assess the spatial and temporalpatterns of root growth and decomposition from 0.10 to1.00 m. Simultaneously,we grew all crops in soil columns to measure destructively C and N content intheroots. We concluded that wheat root decomposition was not affected by covercrop species. In contrast,during the growing season of wheat root decompositionof yellow mustard was on average twice as high for phacelia and sunflower as aconsequence of a higher production of roots with a significantly higherC/Nratio compared to the other cover crops.