Soil Fertility Status of the Lake Liambezi Maize Farm and Implication for Sustainable Cultivation

The Lake Liambezi area in the Zambezi Region of Namibia has a very high potential for maize farming. However, the intensive maize production and poor cultivation practices in this area could lead to soil degradation due to nutrient loss and changes in soil physiochemical properties, which have adverse implications for sustainable cultivation. Thus, this study determined the soil fertility status of the Lake Liambezi maize farms in relation to maize crop nutrient requirements, and, hence, estimated the potential for sustainable cultivation. Soil samples were randomly collected from a total of 21 maize farms in the area. An area of one hectare (1 ha) was marked in each farm and divided into two sampling grids (0.5 ha each) per farm, giving rise to 42 sampling grids. Then, two soil samples were collected within each sampling grid at depths of 0–15 cm (topsoil) and 15–30 cm (subsoil). Thus, a total of 84 soil samples were collected and analyzed using standard laboratory procedures for soil texture, pH, organic matter content, nitrogen, phosphorus, potassium, calcium, magnesium, sodium, and electrical conductivity, respectively. Descriptive statistics were used to analyze the data generated from replicate analyses of the soil parameters and the mean levels were compared with standard maize crop growth nutrients requirement and the soil parameters. Additionally, one-way Analysis of Variance (ANOVA, p < 0.05) was used to determine the significance of mean data variations between the maize farms. Within the two soil depths sampled, the mean results obtained across the maize farms revealed that the farms’ soils have heterogeneous soil characterized by loamy sand, sandy loam and loamy textural classes, neutral pH (7.08 and 7.27), low electrical conductivity (513.01 μS/cm and 481.83 uS/cm), low organic matter (1.63% and 1. 59%), low nitrogen (0.062% and 0.060%), low phosphorus (8.29 ppm and 5.59 ppm), very high potassium (453.86 ppm and 541.38 ppm), very high magnesium (222.19 ppm and 218.19 ppm), very high calcium (3579.57 ppm and 3329.31 ppm), and high sodium (202.19 ppm and 169.05 ppm). The low levels of nitrogen and phosphorus across the farm soils post risk for sustainable maize cultivation in the study area.