Land Degrad. Develop. (2009) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/ldr.953
RUNOFF, SOIL LOSS, AND NUTRIENT DEPLETION UNDER TRADITIONAL AND ALTERNATIVE CROPPING SYSTEMS IN THE TRANSMEXICAN VOLCANIC BELT, CENTRAL MEXICO
M. BRAVO-ESPINOSA1, M. E. MENDOZA2*, L. MEDINA-OROZCO3, C. PRAT4, ´ ´ F. GARCIA-OLIVA5 AND E.LOPEZ-GRANADOS6
´ Instituto Nacional de Investigaciones Forestales, Agrıcolas y Pecuarias. Campo Experimental Uruapan. Av. Latinoamericana Num. 1101, ´ ´ Col. Revolucion CP 60150. Uruapan, Mexico 2 ´ ´ ´ ´ Centro de Investigaciones en Geografıa Ambiental, Universidad Nacional Autonoma de Mexico. Antigua Carretera a Patzcuaro No. 8701, ´ ´ Col. Ex-Hacienda de San Jose de la Huerta CP 58190, Morelia,Mexico 3 ´ ´ Facultad de Biologıa, Universidad Michoacana de San Nicolas de Hidalgo. Ciudad Universitaria, Ediﬁcio B4, C.P. 58060, Morelia, ´ Mexico 4 ´ ` IRD-LTHE (Laboratoire d’etude des Transferts en Hydrologie et Environnement) Equipe RIVER (Rivieres, Erosion et contaminants) Domaine ` Universitaire 460, rue de la piscine 38 400 Saint Martin d’Heres, France 5 ´ ´ ´ Centro de Investigaciones enEcosistemas, Universidad Nacional Autonoma de Mexico. Antigua Carretera a Patzcuaro No. 8701, Col. Ex´ ´ Hacienda de San Jose de la Huerta CP 58190, Morelia, Mexico 6 ´ ´ ´ ´ Departamento de Geologıa y Mineralogıa, Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo. ´ Ciudad Universitaria, Ediﬁcio U, C.P. 58060, Morelia, Mexico Received 14 July 2009; Revised 7September 2009; Accepted 6 October 2009
ABSTRACT ˜ In the Transmexican Volcanic Belt a traditional fallow system is practiced, called ‘‘ano y vez’’ (AV), which does not beneﬁt soil conservation due to its low level of nutrient recycling and because soil protection is poor during the cultivation year. The objective of the present work was to measure runoff and soil and nutrient losses duringthree annual cycles (2002–2004) in Central Mexico under AV rotation and two alternative systems: improved traditional (IT) and traditional organic (TO). Soil losses in the three systems were moderate ( rest; however, this effect is only temporary, soil density being reduced once tilling is restarted. Lado et al. (2004) found similar results, mostly in soils with predominance of smectitic clays.Copyright # 2009 John Wiley & Sons, Ltd. LAND DEGRADATION & DEVELOPMENT, (2009) DOI: 10.1002/ldr
RUNOFF, SOIL LOSS, AND NUTRIENT DEPLETION
Figure 4. Distribution of frequencies of rainfall intensity in the study area for the years 2003 (A) and 2004 (B).
Regarding the differences in runoff observed between furrow cropping (2002 and 2004) and seed casting (2003) (Table III), it can be seenthat the former resulted in a runoff corresponding to between 2 and 6 per cent of the annual rainfall, while in the latter (black oat) that percentage was larger (between 7 and 10 per cent). Analysis of the relation rainfall-runoff for the case of black oat cropping revealed that, irrespective of the type of management, runoff occurred whenever rainfall exceeded 7 mm with a maximum intensity of 12mm hÀ1 within a 10 min period. A series of hydrograms generated during a precipitation event which occurred on 26 June 2004, 18 days after sowing, was further analyzed (Figure 5). The rainfall event lasted 56 min (from 13:17 to 14:13) in which 22 mm of rainfall fell. The maximum rainfall intensities for 10 and 30 min period (I10 and I30) were 34.8 and 28.4 mm hÀ1, respectively. Previous soilconditions were as follows: soil water tension recorded one day before the abovementioned rainfall event was 0 kPa and the accumulated rainfall volume during the previous 5 days was 31.4 mm.
Table III. Runoff volumes (mm) and runoff coefﬁcients (mm mmÀ1) for the three cropping systems assessed Crop/fallow year Annual rainfall (mm) AV R F, Bb: 2002 O: 2003 F, MB: 2004 Mean 899 725 1002 875 54 a 48 a...