Excessive vine growth in sweetpotato has been associated with lower storage root yield. Prohexadione–calcium (Pro-Ca), a plant growth retardant, has been used to reduce vegetative growth and increase harvest efficiency and yield in many fruit and row crops. The influence of Pro-Ca on sweetpotato (Ipomoea batatas Lam.) vegetative growth and storage root yield was evaluated in this study. In 2010 and 2011, the sweetpotato cvs. Beauregard, Porto Rico, O’ Henry, and SC1149-19 were sprayed with 0 and 810 mg a.i./L Pro-Ca in a split plot randomized complete block. Each plot received two sprays, the first at 2 weeks after transplanting and the second at 6 weeks after transplanting. When averaged across cultivars, Pro-Ca significantly (P ≤ 0.05) reduced vine length and vine yield and increased total root yield compared with the control. There was no significant Pro-Ca × cultivar interaction on any trait. Total biomass was not significantly (P ≤ 0.05) different between Pro-Ca-treated and control plants. However, the treated plants had more total root yield, whereas the control plants had more vine yield, suggesting that Pro-Ca treatment affected the distribution of assimilates. Data from this study suggested that it may be possible to use Pro-Ca to manipulate the source-sink relationship for higher storage root yield in sweetpotato.

Controlled fermentation of Sweet potato (Ipomoea batatas) var. Beauregard by yeast, Saccharomyces boulardii (MAY 796) to enhance the nutritional value of sweet potato was investigated. An average 8.00 × 1010 Colony Forming Units (CFU)/g of viable cells were obtained over 5‐day high‐solid fermentation. Yeast cell viability did not change significantly over time at 4°C whereas the number of viable yeast cells reduced significantly at room temperature (25°C), which was approximately 40% in 12 months. Overall, the controlled fermentation of sweet potato by MAY 796 enhanced protein, crude fiber, neutral detergent fiber, acid detergent fiber, amino acid, and fatty acid levels. Development of value‐added sweet potato has a great potential in animal feed and human nutrition. S. boulardii‐ fermented sweet potato has great potential as probiotic‐enriched animal feed and/or functional food for human nutrition.

Polymers are known for controlling fluid loss and modifying rheology in drilling muds through polymer chain entanglement and polymer-solvent interactions. Natural polymers have been used in the formulation of drilling muds, mainly due to their high molecular weight and eco-friendliness but they have limitations in controlling fluid loss, modifying viscosity or forming good gel strength in saline and thermal environments. This study reports laboratory evaluation of Terminalia mantaly exudates as viscosifier in drilling mud formulations. The effects of polymer concentrations, temperature, pH and salinity on the rheological properties of this novel biopolymer were investigated. Results obtained show that as polymer concentration increases (0.5% – 2.5%w/v), the rheological properties (apparent viscosity, plastic viscosity and yield point) of the biopolymer increased. At the polymer concentrations investigated, an increase in temperature (80°F-150°F) results in a slight decrease in the rheological properties of the polymer. At 2%w/v polymer concentration, an increase in salinity results in a slight decrease in its rheological properties, while at 1.5%w/v polymer concentration, an increase in pH (4-10) shows no significant change in the rheological properties. The shear stress increases with increase in shear rate and obeys the Bingham plastic model. The results obtained show that the polymer has a good alkaline resistance at pH above 7 and stable rheological properties at increased salinity and temperature. This has been attributed to the stable repulsive forces of the negatively charged polyelectrolyte of the polymer as salinity increases. From the results obtained in this study, Terminalia mantaly exudate can be a substitute for conventional natural polymers in water-based drilling muds.

Drilling muds are designed to perform certain functions of drilling operation. Some of the functions are to cool and lubricate the drilling bit, transmit hydraulic power to drill bit, provide filter cake and remove drilling cuttings and maintaining wellbore stability. Various additives with specific properties are added in the mud to help prevent the challenges encountered during drilling process. The work studies the effect of pH and salt on the rheological properties of drilling mud formulation from two natural polymers (Terminaliamantaly(TM) exudate and Guar gum) with the use of Model 35 viscometer. Drilling mud formulation with these polymers was investigated at pH of (7.05, 8.15, 10.07, and 11.13) and salt concentrations of (2, 4, 6, 8 and 10g/ml). Results obtained from drilling mud with TM exudate were compared with drilling mud with guar gum. It was found thatthe rheological properties of drilling mud with Terminaliamantaly exudates increased for higher pH as compared to drilling mud with Guar gum. The increase in salinity reduced the effectiveness of the rheological properties of the mud such that as the salinity in drilling mud increased, the rheological properties of drilling mud with Terminaliamantaly and Guar gum decreased. The performance is attributed to flocculation, dispersion and hydration behavior of particles in the mud.

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