In this study, biodegradable slow-release fertilizer (SRF) hydrogels were synthesized from hydroxyl propyl methyl cellulose (HPMC), polyvinyl alcohol (PVA), glycerol and urea (SRF1) and HPMC, PVA, glycerol, urea and blended paper (SRF2). The fertilizer hydrogels were characterized by SEM, XRD and FTIR. The swelling capacity of the hydrogels in both distilled and tap water as well as their water retention capacity in sandy soil were evaluated. The hydrogels had good swelling capacity with maximum swelling ratio of 17.2 g/g and 15.6 g/g for SRF1 and SRF2 in distilled, and 14.4 g/g and 15.2 g/g in tap water, respectively. The water retention capacity of the hydrogels in sandy soil exhibited higher water retention when compared with soil without the (SRFs). The soil with the hydrogels was found to have higher water retention than the soil without the hydrogels. The slow-release profile of the hydrogels was also evaluated. The result suggested that the prepared fertilizer hydrogels has a good controlled release capacity. The blended paper component in SRF2 was observed to aid effective release of urea, with about 87.01% release in soil at 44 days compared to the pure urea which was about 97% release within 4 days. The addition of blended paper as a second layer matrix was found to help improve the release properties of the fertilizer. The swelling kinetic of the hydrogel followed Schott’s second order model. The release kinetics of urea in water was best described by Kormeye Peppas, suggesting urea release to be by diffusion via the pores and channels of the SRF, which can be controlled by changing the swelling of the SRF. However, the release mechanism in soil is best described by first order kinetic model, suggesting that the release rate in soil is depended on concentration and probably on diffusion rate via the pores and channels of the SRF.
This study was conducted to determine the effects of neem (Azadirachta indica A. Juss) and moringa (Moringa oleifera) seed oils on the storability of cowpea grain. Cowpea samples were treated with various concentrations (0.5, 1.0, and 1.5 mL/200 g cowpea) of pure neem and moringa oils and their mixtures in ratios of 1:1, 1:2, and 1:3. The treated cowpea samples were stored for 180 days. Data were collected every 30 days on number of eggs laid, total weevil population, and percentage of uninfested grains and analysed statistically. Significantly different means were compared using LSD at P < .05. Increasing oil concentration resulted in better cowpea protection, for example, in oviposition where the control had 6513 eggs, only 8 eggs were recorded in pure neem oil-treated sample at 0.5 mL/200 g. Generally, better results were obtained with higher oil concentrations either in their pure forms or mixtures. The control had a total weevil population of 4988, while most treated samples had none. The control samples had 0% uninfested grains, while 73-94% of uninfested grains were observed in treated samples after 6 months of storage. Therefore, mixture of the oils at 1.5 mL/200 g can be effectively used to store cowpea.
Simulation models have the potential of greatly enhancing decision‐making by farmers and researchers in Nigeria. These models however, need to be adapted before use. This study was conducted to test the phenology module of CERES‐Maize model version 3.5 under varying N rates as a step toward adapting the model in the Southern Guinea Savanna of Nigeria. Data on seven late‐maturing cultivars of maize (Zea mays L.) grown under 0, 30, 60, 90, and 120 kg N ha−1 in the field for two seasons were used for running the model. There was a linear relationship between N rates and days to silking and maturity with R2 values of > 0.70 for most of the cultivars, indicating that N strongly influenced phenology. Predictions of days to silking at high N rates (90 and 120 kg N ha−1) were close, with most prediction errors of <2 d. The highest deviations in the calibration results were 4 and 2 d for 90 and 120 kg N ha−1, respectively, while in the validation results, they were 1 and 2 d. Similarly, days to maturity were closely predicted by the model at high N rates with <2‐d deviations for most predictions. At low N rates, however, there were greater deviations in model predictions. This shows that the CERES‐Maize model can be reliably used for predicting maize phenology only under nonlimiting N conditions. Thus, a N stress factor needs to be incorporated into the model for more accurate phenology prediction in low‐N tropical soils.
The toxicity of the mixture of neem and moringa seed oils in the ratio of 1:3 was evaluated based on some biomarkers of liver and kidney functions of Wistar Albino rats. Thirty male Wistar albino rats were randomly divided into six groups of five rats each. Group A served as control. Groups B, C, D, E and F received doses of 100, 1000, 1600, 2900 and 5000 mg/kg body weight of ratio 1:3 neem-moringa seed oil, respectively. The albino rats were observed for any changes for seven days; during this period, they were allowed free access to food and water ad-libitum. The rats were weighed and made to fast overnight. The serum obtained was used to determine the serum level of alanine transaminase (ALT), alkaline phosphatase (ALP) and aspartate aminotransferase (AST). Similarly, liver and kidney tissues were removed and homogenized separately in a normal saline in ratio of 1:10 w/v. The homogenate of liver was centrifuged and the supernatant was used to determine total protein and billirubine while that of kidney was used for determining creatinine and urea. The results of all the biochemical parameters tested did not show any significant difference (P>0.05) from the control up to the dose of 5000 mg/kg body weight and did not produce any visible toxic effect. The dosage of 1:3 mixtures of neem-moringa seed oils appeared to be safe for humans.
16' E and 696 m above sea level) to study the effect of nitrogen (N) and phosphorous (P) rates on some phenological and yield characteristics of sesame. The treatments consisted of four N rates: 0, 30, 60 and 90 kg ha -1 and four P rates: 0, 15, 30 and 45 kg ha -1 . These treatments in factorial combinations were laid out in split plot design with N rates assigned to main plots and P rates assigned to sub plots and were replicated four times. The following data were collected on phenological and yield characteristics: days to 50 % flowering, days to 50 % maturity, weight of biomass at eight weeks after sowing (WAS) and at harvest, dry weight of leaves at 8 WAS and at harvest, number of pods per plant and total seed yield. Results showed significant (P < 0.05) effect on all characteristics, except number of leaves at 8 WAS and days to 50 % maturity in both cropping seasons. Similarly, there were significant effects of N rates on dry weight of leaves, weight of biomass at harvest and number of pods per plant up to a maximum of 90 kg N ha -1 . P rates showed no significant effect on all characteristics measured. There was an interaction between cropping seasons and N rates on weight of biomass at 8 WAS and number of pods per plant. It was therefore concluded that application of N had a significant effect (P < 0.05) on some yield characteristics of sesame in Mubi. P rates up to 45 kg ha -1 however, had no significant (P > 0.05) effect on phenological and yield characteristics. Further research needs to be conducted on N and P rates above 90 and 45 kg ha -1 , respectively, to ascertain effects of optimum rates of N and P on sesame phenological and yield characteristics. In addition, the method of P application in the form of side dressing 2 to 3 WAS should be considered for possible effects.
Phytochemical composition of leaf extracts as well as biological effects of juice, leaf extracts and seed oil of Jatropha curcas against Sitophilus zeamis were examined. The study also investigated the inhibition of oviposition, progeny production and grain damage, insecticidal effects and mammalian toxicity of the extracts. Compared to other phytochemicals, the concentration of saponin and cardiac glycoside were higher in the leaf extract. All extracts of J. curcas (0 -100 ppm) investigated showed a dose-dependent inhibition of ovisposition, progeny production and promote significant (P < 0.001) insect mortality. Grains pre-treated with seed oil produced the highest result for all the parameters. The seed oil (100 ppm) produced 93% (P < 0.001) protection against grain damage by Sitophilus zeamis. Observable physical deformities were observed in rats administered with graded doses of the seed oil as opposed to other extracts. Administration of a single dose of the extracts produced significant (P < 0.01) elevation of serum level of alanine (ALT) and aspartic (AST) transaminases and alkaline phosphatase (ALP) in rats.
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