Abstract
Sodic soils could produce useful maize (Zea mays L.) crop yields if reclaimed by appropriate techniques. A field experiment was conducted on the selected lowlands of northern Tanzania using a randomised complete block design to study the effectiveness of supplying gypsum (CaSO4.2H2O) or farmyard manure (FMY) alone or both mixtures on the reclamation of a sodic soil. Sodic soil and FYM were characterised to establish their quality status before any intervention was introduced. The treatment used included: control, FYM alone (25 t ha-1), FYM (25 t ha-1) combined with gypsum (12.5 t ha-1) and gypsum alone (12.5 t ha-1). The treatments were replicated four times. Selected numbers of soil physical and chemical properties were then investigated. Results from our study revealed that regardless of the amendments used, maize yield and all soil physical and chemical properties tested were improved in Year 2 (Y2) relative to Year 1 (Y1). Our results also showed that combining FYM with gypsum significantly (p0.05) improved pH, electrical conductivity of the saturated paste (ECe), exchangeable sodium percentage (ESP), infiltration rate (IR), osmotic potential (OP) and available water capacity (AWC) of sodic soils. The FYM was the second-best treatment in the improvement of pH, ESP and EC whereas gypsum was second in the improvement of ESP, IR and maize yield.
Highlights
Soil degradation caused by salinisation and sodification is of great concern in the modern world because it reduces potential agricultural lands (Tanji, 1990; Maas and Grattan, 1999; Sadiq et al, 2007)
The field experiment was conducted in year 2002 (Y1) and 2003 (Y2) on sodic soils of the Rundugai traditional irrigation scheme in Hai District, Kilimanjaro Region
Results from our study revealed that regardless of the amendments used, all physical and chemical properties tested were improved in Year 2 (Y2) relative to Year 1 (Y1) (Tables 1 and 2)
Summary
Soil degradation caused by salinisation and sodification is of great concern in the modern world because it reduces potential agricultural lands (Tanji, 1990; Maas and Grattan, 1999; Sadiq et al, 2007). The main source of salt in arid and semi-arid areas includes rainfall (Rengasamy and Olsson, 1993), mineral weathering (Lindsay, 1979; Gunn and Richardson, 1979; Macumber, 1991), irrigation and various surface waters (Mehanni and Chalmers, 1986; Rengasamy and Olsson, 1993; SPORE, 1995), groundwater which redistributes accumulated salts during evaporation (Macumber, 1991), chemical applications (Rengasamy and Olsson, 1993) and man activities (Dregne, 1976) These sources, coupled with environmental modifications, lead to three different classes of salinisation and sodification that are grouped so for management purposes. These classes include: saline (ECe>4dSm-1, ESP15%, pH8.5) (Richards, 1954)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
