Properties and Sensibility to Physical Degradation of Soils Under Cotton Cropping in Korola Watershed, Sikasso Region, Mali
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Asian Journal of Soil Science and Plant Nutrition 2(4): 1-10, 2017; Article no.AJSSPN.38075 ISSN: 2456-9682 Properties and Sensibility to Physical Degradation of Soils under Cotton Cropping in Korola Watershed, Sikasso Region, Mali Habibatou Sangaré1, Drissa Diallo1* and Issa Kassogué2 1Unité des Sciences du Sol, DER STA, IPR/IFRA de Katibougou, BP 6, Koulikoro, Mali. 2ICRISAT- Regional Hub West and Central Africa, BP 320, Bamako, Mali. Authors’ contributions This work was carried out in collaboration between all authors. Author HS designed the study, performed the statistical analysis, wrote the protocol and wrote the first draft of the manuscript. Authors DD and IK managed the analyses of the study. Author DD managed the literature searches. All authors read and approved the final manuscript. Article Information DOI: 10.9734/AJSSPN/2017/38075 Editor(s): (1) Darmawan, Associate Professor, Department of Soil Science, Faculty of Agriculture, Andalas University, West Sumatra, Indonesia. (2) Prabhakar Tamboli, Adjunct Professor & Director International Training Program, Department of Environmental Science & Technology, University of Maryland, College Park. Maryland 20742, USA. (3) Rusu Teodor, Professor, Agrotechnics, Experimental Techniques and Rural Development, Department of Technical and Soil Sciences, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Romania. Reviewers: (1) Diony Alves Reis, Federal University of Western Bahia, Federal University of Pelotas, Brazil. (2) Miguel Aguilar Cortes, Universidad Autonoma Del Estado De Morelos, Mexico. Complete Peer review History: http://www.sciencedomain.org/review-history/23206 Received 10th November 2017 th Original Research Article Accepted 9 February 2018 Published 16th February 2018 ABSTRACT Soil physical, chemical and biological degradation is a global problem, which must be monitored by each country in order to have better decision-making for agriculture and environment. In this case, study has been undertaken in Mali at agricultural watershed scale. The present paper is related to Korola watershed (1245.3 km2). Here, and in the major part of Sikasso region, cotton cultivation for industry was introduced during the 1960s. Soil degradation is considered as a handicap to the improvement of cotton production, a general problem in Western and Central Africa. A deeper understanding of soils and their sensibility to degradation is needed in order to choose better strategies to improve their management and productivity. The methodology used in the present study includes soil profile descriptions, particle size analyzes, carbon, nitrogen and pH measurement, the use of pedotransfer functions to assess soil structure and their sensitivity to erosion. In Korola watershed, 3 soil types (soil1, soil2, soil3) are selected by farmers for cotton _____________________________________________________________________________________________________ *Corresponding author: Email: [email protected], [email protected]; Sangaré et al.; AJSSPN, 2(4): 1-10, 2017; Article no.AJSSPN.38075 cropping. Soil1 (Guinin dugukolo) and soil2 (Mura dugukolo) have a high amount in silt, while soil3 (Ciencien dugukolo) is rich in sand. All these soils are poor in organic matter (≤ 1%) and present a high risk of acidification. The index of battance (IB) of surface horizons (respectively 15.9, 11.0 and 15.4 for the three types soils) indicate a unfavorable structure. The destructuration index (St) indicate a high sensibility to soil erosion. The values of soil erodibility index (K) are respectively 0.44; 0.55 and 0.09 for the three types of soils. Keywords: Watershed; cotton; soil physical degradation; Bagoe River; Sikasso Region; Mali. 1. INTRODUCTION their fundamental properties and their behavior. The purpose of the study in Korola watershed is Soil physical, chemical and biological to identify and to characterize the types of soils degradation is a global problem. It is noted that affected to cotton cultivation by farmers. the mapping of soil degradation shows a varying magnitude of the problem worldwide. In the 2. STUDY AREA tropics, accelerated soil degradation affected as much as 500 million ha [1]. Soil degradation The Korola watershed (Fig. 1) is a sub-basin of leads to a reduction or even a loss of its Bagoé medium. The coordinates at the outlet are productivity and crop yields. In addition, it 6°23’45’’W and 11°42’54’’N; the altitude is 304 negatively impacts water resources and m. It covers 1245.3 km2 in Sikasso region, environment moderating capacity. In 1995, the where 3 rural communes (Blendio, Dembela, mean loss of yield due to past erosion in Africa, Koufan) are fully inscribed there, as well as was estimate to 9% [2]. For this continent, yield villages of the communes of Miria, Niéna, reductions by 2020 may be 16.5%, if Tiankadi and Kapolondougou. Fig. 1 shows the acccelereted erosion continues unabated. Today, location of the Korola watershed on the map of it is clear that soil degradation must be monitored Mali (upper part). The boundaries of the by each country in order to have better decision- watershed are shown in the lower part. making for sustainable agriculture, as well as better quality of environment. So, there is a need Korola watershed is located in the western of reliable assessment tools for the various Sudano-Sahelian belt, a semi-arid region. There aspects of soil degradation. Concerning physical is only one rainy season (from May to October) degradation, the disponibility of values related to where annual rainfall is very variable. At the some indexes of soil structure and soil erodibility reference meteorological station (the Sikasso index (K) is necessary. Numerous studies have one), during the last 36 years (1986-2016), the shown the variability of these indexes, depending two extreme values of annual rainfall were 754.7 on soils fundamental properties and its mm in 1983 and 1552.8 mm in 2016. The environment [3,4,5,6]. Soil sensibility to monthly precipitation is mainly concentrated in degradation process must be studied in the the period July-September. The annual values of different physical and agrosystem contexts. With the potential evapotranspiration (PET) are these considerations, studies have been variable from 1634 to 2424 mm. The wind speed undertaken in Bagoé river basin in Sikasso is low (generally 2 km.h-1), but exceptional region, Mali. They were precisely conducted in speeds are often recorded in May and June (72 the Korola watershed that cover an area of km.h-1). The monthly maximum temperature is 1245.3 km2, in the administrative district of higher in March (average 37.5°) and lower in Blendio. Industrial cotton cultivation was August (29.9°). Monthly minimum temperature, is introduced in this zone during the 1960s. It higher in April (24.3°) and lower in January should be noted that, land degradation is (12.9°). considered as a serious handicap to the improvement of cotton production in Western and Korola watershed is located on sedimentary Central Africa [7,8,9]. Cotton farming is highly formations in a border area with the Precambrian mechanized (plowing, hilling, etc.) and promotes granite basement. The basic lithological rapid soil degradation in Sudanese areas of formations in the watershed are sandstone, subSaharan Africa. A program for improving the schist and mixture sandstone-schist. Schist and integrated management of soil fertility under sandstone have been strongly altered, but cotton cultivation must take into account soils unaltered rocks remain in some places. However diversity and be based on a good knowledge of large surfaces are covered by ferruginous 2 Sangaré et al.; AJSSPN, 2(4): 1-10, 2017; Article no.AJSSPN.38075 cuirass, usually in a tabular position. The main Korola watershed is populated by more than soils were developed from ferruginous cuirass 42,700 inhabitants in 43 villages. It is entirely material and colluvium [10]. located in the Malian cotton zone. The main crops are cotton, maize, sorghum and millet. The watershed is located in a savannah Other annual crops that include rice, fonio, and ecosystem. A normal distribution of the groundnuts, as well as horticultural crops are vegetation is noted, depending on soil patterns cultivated in the watershed. The farmers are and relief. Pedological material influence the generally well equipped with animal-drawn floristic composition of the vegetation or at least equipment, allowing the mechanization of several the relationships of dominance and frequency. farming operations [11]. Livestock are mainly The forest gallery is observed along streams. cattle, sheep, goats and donkeys. Fig. 1. Location of the study area 3 Sangaré et al.; AJSSPN, 2(4): 1-10, 2017; Article no.AJSSPN.38075 3. METHODS Martin-Lafleche [13]; R equation for soils with pH < 7 is considered in this study. 3.1 Soil Morphological Characterization - The destructuration index (St), with the and Sampling function presented by Pieri [14]. The indexes R, IB and St are presented The pedological descriptions were carried out in respectively by Eq1, Eq2 and Eq3: pits (measuring 1 m long, 0.80 m wide and 1.20 m as maximum deep), auger drilled holes and ,∗ ,∗ = (1) some pre-existing cavities (natural and artificial). (∗) Soil profile description criteria were: the thickness and depth of major horizons, their IB = 5 ( − 0.2) (2) color, texture and structure, the presence of = ∗ 100 (3) coarse particle, the presence of oxidation and ( ) ferruginous concretions, rooting and biological activities.