Bankole Olawale

Sulfur (S) availability and release are important parameters in managing soil S status for optimum crop performance. Experiments were conducted to investigate the effects of cattle manure (CM), CM and wood ash (CM + WA), poultry manure (PM), PM + WA, and WA on S release and uptake in maize. The incubation and greenhouse experiments were arranged in a completely randomized design. The field experiment was in a randomized complete block design. Soils were collected from different agro-ecological zones. Animal manure and WA were applied at 45 kg S ha −1 and 5 t ha −1 , respectively. Samples were analyzed for S release at 4-week interval, and S uptake and dry matter weights were determined after harvest. Data were subjected to regression (R 2) analysis and ANOVA at p ≤ 0.05. Results revealed amendments significantly increased soil S over the control in order of PM > CM > PM + WA > CM + WA > WA and S release was maximum at 4th week by 27.8, 20.7, and 91.1% in incubation, greenhouse, and under field conditions, respectively. PM recorded the most consistent S release in incubation and greenhouse, and the magnitude of S release on the field was higher in CM + WA by 108%. The R 2 between S release and time among treatments ranged from 0.5576 to 0.9999. S uptake in shoot and grain was 60 and 90% higher in PM-and PM + WA-amended plots, respectively, than the control. The study concluded that the application of manure at 45 kg S ha −1 with or without wood ash improved the release rate of S above the critical limit for optimum maize performance.

Monitoring and quantification of nutrient movement in soils could help farmers and policy makers to formulate effective nutrient loss reduction strategies and waste management. The study was conducted to monitor and quantify vertical and lateral movements of nitrate-nitrogen (NO 3-N), phosphate (PO 4) and sulphate-sulphur (SO 4-S) in soils around manure dumpsites in Abeokuta, southwest Nigeria. The dumpsites investigated include a flush-type poultry litter, poultry litter mixed with beddings of wood shavings and cattle and pig waste open dumpsites. Soils were sampled at depths of 0-20, 20-40, 40-60 and 60-80 cm and at distances 2, 4, 6, 8, 10, 20, 40, 60 and 80 m away from the dumpsites. Soil samples were analysed for some physical and chemical properties and NO 3-N, PO 4 and SO 4-S contents. Results indicated that there were more nutrients in the soil around the poultry manure slurry dumpsite compared with others while the soil pH increased with increase in soil depth, across dump sites. There was evidence of leaching of salts, and this correlated positively with the soil organic matter content (r = 0.41, p < 0.01). The soils were polluted with NO 3-N, PO 4 and SO 4-S as deep as 80-cm depth; these nutrient amounts were higher than the maximum allowable (40, 15 and 7 mg kg −1 , respectively) for southwest Nigerian soils. Due to high soil organic matter and for agronomic considerations, the soils are only suitable for cultivation at depths below 40 cm and 8 m away from the dump sites. There was significant pollution of the soils with nitrate, phosphate and sulphate, within 80 m distance from the dump site. This has serious implications for ground water recharges and shallow well sunk around these areas. There is potential risk of NO 3-N, PO 4 and SO 4-S consumption through such water sources.

Iron-impregnated filter paper (Fe-Pi) was evaluated as phosphorus (P) extractant in four soils of Ogun state, southwest Nigeria in a screenhouse experiment. The experiments lasted for 8 weeks. Soil P contents were extracted at 0, 4, and 8 weeks after the incorporation of amendments (cattle manure, poultry manure, and wood ash) using Fe-Pi, Bray-1, Bray-2, Mehlich-1, Hunter, and Olsen extractant. Agronomic variables were taken fortnightly from grown maize plants and later harvested at 8 weeks, residual effects of the treatments were also evaluated. Maize dry matter weight (DMW) and P uptake were also measured. Results indicated that a linear relationship existed among the extractants with significant coefficient at p ≤ .001. Fe-Pi established a strong relationship with the conventional extractants in the following order: Bray-1 (R 2 = 0.99) > Bray-2 (R 2 = 0.98) > Hunter (R 2 = 0.96) > Mehlich-1 (R 2 = 0.86) > Olsen (R 2 = 0.82). Fe-Pi had a significant relationship with P uptake and DMW. Phosphorus uptakes under the animal manure amendments were statistically higher than uptake in control and woodash amended soils. Therefore, the study concluded that Fe-Pi was a good predictor of plant available P and had significant relationship with Bray-1, thus it could be considered for the estimation of soil available P in soils of southwest Nigeria.

Sulfur (S) fractions, distributions and sorption characteristics of some soils in Ogunstate, Southwestern Nigeria, were evaluated in ten different locations, the area lies with in the Derived Savannah and forest agro-ecological zone. Result showed available, adsorbed, organic and total S ranged from 3.9 to 19.8, 16.3 to 36.6, 214.9 to 412.9 and 248.8 to 446.6 mg kg −1 respectively. Organic S constituted 86.4 to 93.4% of total S. The mean status of available S was slightly above the critical limit of 10 mg kg −1. All fractions of S maintained significant positive correlation (p ≤ .05) with each other and total organic carbon, while available and adsorbed S had significant and negative correlation with soil pH, total nitrogen, available phosphorus and calcium. The S sorption behavior of the soils varied and increased with increase in S concentrations of equilibrium solution. The isotherm model for the ten locations was S-curved type. Sorption data were fitted to Langmuir and Freundlich sorption isotherms. Langmuir equation was best fitted to the S adsorption data in the ten locations except soils from Owode, Odeda and Ikenne. Langmuir and Freundlich parameters (sorption maxima, binding energy and maximum buffering capacity affinity constant and slope) were significantly correlated with some soil properties.

A 16-week incubation experiment was conducted to determine the pattern of nitrogen (N), phosphorus (P), and sulphur (S) mineralization in soils treated with poultry manure slurry (PMS), poultry manure with bedding (PMB), cattle manure (CM), horse manure (HM), rabbit manure (RM), swine manure (SM), and goat and sheep manure (GSM) applied at 120 kg N ha −1. The concentrations of nitrate-N (NO 3-N), ammonium-N (NH 4-N), total mineral nitrogen (TMN), available P, and S were determined fortnightly. The result showed that SM and HM had significantly (p ≤ 0.

Studies on the effect of biochar, manure and manure ash on soil nutrient kinetics are rare. Therefore, an incubation study was conducted to investigate nitrogen (N), phosphorus (P), and sulphur (S) kinetics in soils amended with biochar (B), B + cattle manure (BCM), B + goat and sheep manure (BGSM), B + poultry manure (BPM), farm yard manure (FYM), CM ash (CMA), GSMA, PMA, and wood ash (WA). Manure and manure ash were applied at 120 kg N ha −1 ; B was applied at 5 tha −1 .Total mineral nitrogen (TMN), available P and S were determined at 2 weeks interval. Results revealed that soils treated with WA and PMA had the highest liming (pH 9.88) and salinity (820 μS m −1), respectively. The overall cumulative release of TMN, P and S in soil treated with PMA was 1, 7 and 16% higher than BPM amended soils, respectively. The least percentage of TMN, P and S mineralized was in soil treated with BCM (13.5%), BPM (12.3%) and WA (9.3%), respectively. The first order and power functions were able to capture the kinetic release of N, P and S in the soil and amendments. TMN had significant correlation with nitrate-N (r = 0.925, p ≤ 0.001) ammonium-N (r = 0.737, p ≤ 0.01), sulphate (r = 0.823, p ≤ 0.01) and phosphate (r = 0.702, p ≤ 0.01). The study concluded that the application of manure ash or manure with biochar encourages the timely release of TMN, P and S as well as improving the salinity and pH of the soil.

Monitoring and quantification of nutrient movement in soils could help farmers and policy makers to formulate effective nutrient loss reduction strategies and waste management. The study was conducted to monitor and quantify vertical and lateral movements of nitrate-nitrogen (NO 3-N), phosphate (PO 4) and sulphate-sulphur (SO 4-S) in soils around manure dumpsites in Abeokuta, southwest Nigeria. The dumpsites investigated include a flush-type poultry litter, poultry litter mixed with beddings of wood shavings and cattle and pig waste open dumpsites. Soils were sampled at depths of 0-20, 20-40, 40-60 and 60-80 cm and at distances 2, 4, 6, 8, 10, 20, 40, 60 and 80 m away from the dumpsites. Soil samples were analysed for some physical and chemical properties and NO 3-N, PO 4 and SO 4-S contents. Results indicated that there were more nutrients in the soil around the poultry manure slurry dumpsite compared with others while the soil pH increased with increase in soil depth, across dump sites. There was evidence of leaching of salts, and this correlated positively with the soil organic matter content (r = 0.41, p < 0.01). The soils were polluted with NO 3-N, PO 4 and SO 4-S as deep as 80-cm depth; these nutrient amounts were higher than the maximum allowable (40, 15 and 7 mg kg −1 , respectively) for southwest Nigerian soils. Due to high soil organic matter and for agronomic considerations, the soils are only suitable for cultivation at depths below 40 cm and 8 m away from the dump sites. There was significant pollution of the soils with nitrate, phosphate and sulphate, within 80 m distance from the dump site. This has serious implications for ground water recharges and shallow well sunk around these areas. There is potential risk of NO 3-N, PO 4 and SO 4-S consumption through such water sources.

Sulfur (S) availability and release are important parameters in managing soil S status for optimum crop performance. Experiments were conducted to investigate the effects of cattle manure (CM), CM and wood ash (CM + WA), poultry manure (PM), PM + WA, and WA on S release and uptake in maize. The incubation and greenhouse experiments were arranged in a completely randomized design. The field experiment was in a randomized complete block design. Soils were collected from different agro-ecological zones. Animal manure and WA were applied at 45 kg S ha −1 and 5 t ha −1 , respectively. Samples were analyzed for S release at 4-week interval, and S uptake and dry matter weights were determined after harvest. Data were subjected to regression (R 2) analysis and ANOVA at p ≤ 0.05. Results revealed amendments significantly increased soil S over the control in order of PM > CM > PM + WA > CM + WA > WA and S release was maximum at 4th week by 27.8, 20.7, and 91.1% in incubation, greenhouse, and under field conditions, respectively. PM recorded the most consistent S release in incubation and greenhouse, and the magnitude of S release on the field was higher in CM + WA by 108%. The R 2 between S release and time among treatments ranged from 0.5576 to 0.9999. S uptake in shoot and grain was 60 and 90% higher in PM-and PM + WA-amended plots, respectively, than the control. The study concluded that the application of manure at 45 kg S ha −1 with or without wood ash improved the release rate of S above the critical limit for optimum maize performance.

Sulfur (S) fractions, distributions and sorption characteristics of some soils in Ogunstate, Southwestern Nigeria, were evaluated in ten different locations, the area lies with in the Derived Savannah and forest agro-ecological zone. Result showed available, adsorbed, organic and total S ranged from 3.9 to 19.8, 16.3 to 36.6, 214.9 to 412.9 and 248.8 to 446.6 mg kg −1 respectively. Organic S constituted 86.4 to 93.4% of total S. The mean status of available S was slightly above the critical limit of 10 mg kg −1. All fractions of S maintained significant positive correlation (p ≤ .05) with each other and total organic carbon, while available and adsorbed S had significant and negative correlation with soil pH, total nitrogen, available phosphorus and calcium. The S sorption behavior of the soils varied and increased with increase in S concentrations of equilibrium solution. The isotherm model for the ten locations was S-curved type. Sorption data were fitted to Langmuir and Freundlich sorption isotherms. Langmuir equation was best fitted to the S adsorption data in the ten locations except soils from Owode, Odeda and Ikenne. Langmuir and Freundlich parameters (sorption maxima, binding energy and maximum buffering capacity affinity constant and slope) were significantly correlated with some soil properties.

Sustainable vegetable production especially during the dry season requires adequate conservation of soil water. This study was conducted to evaluate the sole and interactive effects of mulching (M) and poultry manure (PM) application on soil temperature (ST), crop evapotranspiration (ETc) and water use efficiency (WUE) of okra. The experiment was a Randomized Complete Block Design (RCBD) with three replicates. The treatments were M at 0 and 6 t ha À1 and PM at 0, 10 and 20 t ha À1. Soil temperature was measured using digital thermometer while ETc was determined by water depletion method using a Time Domain Reflectometer. Irrigation at field capacity was applied manually at 2-day intervals. Independent application of mulch significantly lowered ST while joint application of 20 t ha À1 PM (PM20) and M significantly (p 0.05) reduced ST at 5 cm and 10 cm soil depth compared with the unmulched plots in both seasons. Application of 10 t ha À1 PM (PM10) without M recorded the highest ETc (43.7 mm), while joint application of PM20 and M reduced ETc by about 93% compared with PM10 only. Okra used water most efficiently when PM20 was applied under mulched plot. There was 62.2% increase in WUE under mulched plots compared with the control while the residual effect of PM10 and M significantly increased WUE by 65.5%. It was evident that M alongside application of PM is a good strategy for regulating ST, moderating ETc and increasing okra WUE, especially during dry season farming.