• Rural Digital Europe
• Cogent Food & Agriculture close

Poor soil fertility status due to erosion, intensive farming, and leaching of nutrients causes food insecurity in Ethiopia. Hence, estimating soil fertility status using different measurements is very essential to secure food insecurity. The aim of this study was to determine the effects of land management on soil fertility using a nutrient balance approach at Kecha and Laguna micro watersheds in 2016. Plant nutrient losses were estimated through measuring discharge and sediment loads coming from the treated (Kecha) and untreated (Laguna) catchments. A total of 40 bulk sediment and water samples were collected on a monthly basis. The inputs used in the two catchments, inorganic fertilizer and organic manure, were quantified through interviews using a semi-structured questionnaire. Plant samples were collected from 92 plots for determining grain yield (OUT1) and straw biomass (OUT2). Other inputs and outputs were calculated using a transfer function. From sediment, grain and straw samples, NPK contents were determined. The nutrient balances were found to be −89.37, −23.66 and −124.75 NPK kg/ha, and −112.41, −20.62 and −130.26 NPK for Kecha and Laguna, respectively. The main paths for these negative balances were residue removal and soil losses. Higher nutrient losses were observed in Laguna than Kecha watershed; this may be due to lack of soil management practices, crop rotation and planting of leguminous plants. Therefore, soil management practices should be done to reduce these higher losses of plant nutrients, and maintain crop residues in the farm so that nutrient recycling and better soil fertility can be achieved.

Though secondary and micronutrients are known to improve crop production, their inclusion in fertilizer formulation has received minimum attention in efforts aimed at increasing maize production in northern Ghana. In this study, Sulphur, Boron, and Zinc were included in NPK formulations at different rates in northern Ghana. The experiment was a single factor, consisting of NPK 15-15-15 applied at rates (kg/ha) of 60-40-40, NPK 15-15-15 at rates of 90-60-60, NPK 15-15-15 at 100-40-40, NPK 11-22-21 + 5S+1B+1Zn at 60-40-38 + 9 + 1.8 + 1.8, NPK 11-22-21 + 5S + 1B + 1Zn at 90-60-57 + 14 + 2.7 + 2.7, NPK 11–22 21 + 5S+1B+1Zn at 100-40-38 + 9 + 1.8 + 1.8, NPS 14-31-0 + 9S + 1B + 1Zn at 60-40-0 + 11.6 + 1.3 + 1.3, NPS 14-31-0 + 9S + 1B + 1Zn at 90-60-0 + 17.4 + 1.9 + 1.9, NPS 14-31-0 + 9S + 1B + 1Zn at 100-40-0 + 11.6 + 1.3 + 1.3 and no fertilization. Treatments were randomly laid out in four farms. Urea at respective rates was applied at 6 weeks after planting. Data analyzed on growth and yield parameters at 5% probability showed that significantly higher growth and yield were recorded with the inclusion of secondary and micronutrients (P < 0.05). NPK 11-22-21 + 5S + 1B + 1Zn at 90-60-57 + 14 + 2.7 + 2.7 increased yield by 30% (mean: 3330 kg/ha) compared to the standard yield from NPK 15-15-15 at 90-60-60 (mean: 2585 kg/ha) which consisted solely of primary nutrients. Also, NPS 14-31-0 + 9S + 1B + 1Zn at 100-40-0 + 11.6 + 1.3 + 1.3 followed with yield increment of 26% (mean: 3252 kg/ha), with the zero-control treatment giving the lowest yield (mean: 356 kg/ha). While the study confirms the need for use of fertilizer in maize production across northern Ghana it demonstrates the need for secondary and micronutrient inclusion in fertilizer blends for soils of Northern Ghana.

Calibration of soil test P is a stage in determining P fertilizer rates to meet plant P requirement and soil nutrient availability. The objective of this study was to determine the critical phosphorous (Pc) and phosphorous requirement factor (Pf) for food barley production. The experiment was laid out in randomized complete block design (RCBD) with two replications. Barley response to different levels of Phosphorus was conducted on Cambisols of Enda mekoni at 10 sites in the Northern Ethiopia during the 2013 and 2014 cropping seasons. The treatments, comprising five levels of P fertilizer (0, 10, 20, 30 and 40 kg P ha−1), were arranged in a randomized complete block design with three replications. The critical concentration and requirement factor of Phosphorus on barley in the study area were 10.5 mg kg−1 and 16.27 mg kg−1, respectively. Hence, it could be concluded that the highest grain yield, P requirement factor and P critical obtained could serve in areas where the rainfall distribution and soil type are similar with study district where this experiment was conducted. Further studies should be done on phosphorous use efficiency and other related plant nutrition parameters.

A study was carried out in the eastern part of Dang district in Nepal to assess the variability of selected soil properties due to different land use and map their spatial distribution. Considering three land use types (agriculture, agroforestry, and grassland), a total of 120 samples were collected from surface soil (0 to 15 cm depth) in May 2015 and analyzed for soil fertility parameters: pH, organic matter (OM), nitrogen (N), phosphorus (P), potassium (K), boron (B), and zinc (Zn). Results revealed that the average value of soil pH significantly (P&lt;0.05) varied from 7.05 in agroforestry to 7.53 in agriculture land use. Soil OM and N contents were medium in range in all land use with slight variation, the highest average OM and N found in grassland (2.87% and 0.14% respectively), followed by agriculture (2.64% and 0.13% respectively), and agroforestry (2.45% and 0.12% respectively). Further, the results showed significant variation for P among agroforestry (18.99 kg ha-1) and grassland (8.49 kg ha-1) while the K content was the highest for grassland (144 mg kg-1) and lowest for agriculture (120 mg kg-1). Micronutrients- B was low (0.28 to 0.35 mg kg-1) and Zn was very low (0.14 mg kg-1) in all land use. There is a need to add appropriate fertilizer N, P, B, and Zn to the soil in order to increase the fertility status under different land use. Spatial variability maps for soil chemical properties can be used by farmers and local planners to make effective soil management strategies.