@article{PAR00000016,
  title = {{S}oil organic matter, surface crusting and erosion in {S}ahelian farming systems based on manuring or fallowing},
  author = {{D}e {R}ouw, {A}nneke and {R}ajot, {J}ean-{L}ouis},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he cultivated soils of the {S}ahel are sandy, very poor in organic matter, and are prone to surface crusting and erosion. {F}armers sustain pearl millet production through permanent cultivation with manure input or long-term fallowing. {D}ue to population increase fallows are reduced bringing on low yields. {T}his on-farm study ({B}anizoumbou, semi-arid {N}iger) examines the impact of clearing and weeding on soil surface processes, the decline in soil organic matter under prolonged cultivation, and whether manure inputs are sufficient to sustain millet production. {S}hort-term effects were examined in a 3-year experiment with dung application (5 {M}g ha(-1)) and weeding frequency (no, two and four weedings). {L}ong-term effects were studied a 4-year experiment comparing three farming systems: (i) permanent cultivation with manure; (ii) cultivation after long fallows >15 years; (iii) cultivation after short fallows 3-5 years. {D}ue to the difference in scale, different processes of erosion were studied, saltation and creep in the first experiment, suspension in the second. {D}ung deposits provided mechanical protection of the soil surface by reducing crusting and by trapping aeolian sand. {A} very low cover of dung, 0.5-5%, is enough to protect the soil effectively by forming barriers against creep and saltation. {S}uspension occurs during tillage. {M}anual cultivation, while disrupting aggregates and surface crusts, enhances wind erosion and this leads to loss of clay and silt from the top soil. {C}hanging from long to short fallow periods and even to permanent cultivation, constitutes a trend towards more intensive land use and this, eventually, leads to extremely sandy top soils (from 890 up to 934 g kg(-1)) and coincidences with a soil surface becoming less crusted (from 49% of field surface affected down to 7%). {M}anure input cannot prevent the erosion of fine earth which seems to be an irreversible feature of long-term cultivation. {D}ung inputs, 0.5-1 {M}g ha(-1) per year, are insufficient to increase substantially millet grain yield (350 kg ha(-1) in manured; 300 kg ha(-1) in long fallow fields), or elevated soil organic matter (2.9 g kg(-1) soil, in manured fields; 4.0 g kg(-1) in long fallow fields, 0-20 cm). {Y}et grain yield remains stable under permanent cropping, while fields without manure need fallowing for long periods to restore fertility. {U}nder short fallows without dung input soil organic matter drops to 2.4 g kg(-1), and grain yields to 125 kg ha(-1). ({C}) 2004 {E}lsevier {B}.{V} {A}ll rights reserved.},
  keywords = {on farm experiments ; long term and short term effect ; crusting ; wind erosion ; pearl millet ; dung ; tillage ; fallow ; texture},
  booktitle = {},
  journal = {{A}griculture {E}cosystems and {E}nvironment},
  volume = {104},
  numero = {2},
  pages = {263--276},
  ISSN = {0167-8809},
  year = {2004},
  DOI = {10.1016/j.agee.2003.12.020},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00000016},
}