We evaluated 17 genotypes of stem amaranth (Amaranthus lividus) in terms of dietary fiber, moisture, carbohydrates, fat, ash, gross energy, protein, minerals, phytopigments, total antioxidant capacity (TAC), vitamins, total flavonoids (TFC), total polyphenols (TPC) and their variations. Stem amaranth leaves have abundant dietary fiber, moisture, carbohydrates, and protein. We found significant amount of potassium, calcium, magnesium (9.61, 24.40, and 29.77 mg g −1 DW), iron, manganese, copper, zinc, (1131.98, 269.89, 25.03, and 1006.53 µg g −1 DW), phytopigments such as chlorophyll a, chlorophyll ab chlorophyll b, (27.76, 42.06, and 14.30 mg 100 g −1 FW), betalain, betaxanthin, betacyanin (62.92, 31.81, 31.12 µg 100 g −1 FW), total carotenoids, beta-carotene (1675.38, 1289.26 µg g −1 fW), vitamin c (1355.46 µg g −1 FW), TPC, TFC (228.63 GAE and 157.42 RE µg g −1 DW), and TAC (DPPH, ABTS +) (26.61, 51.73 TEAC µg g −1 DW) in the leaves of stem amaranth. Genotypes exhibited a wide range of variations. Three genotypes DS40, DS30, and DS26 could be used as an antioxidant profile enriched stem amaranth. Phenolics, phytopigments, flavonoids, and vitamins of stem amaranth leaves exhibited strong antioxidant activity. Stem amaranth could be a potential source of dietary fiber, moisture, carbohydrates, protein, minerals, phenolics, phytopigments, flavonoids, and vitamins in our daily diet for attaining nutritional and antioxidant sufficiency.

A field experiment was conducted during the major cropping season of 2014 at the Plantation Section of the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Ghana to evaluate the effect of tillage and different application rates of phosphorus fertilizer on the growth and yield of sweet potato variety Okumkom. The tillage methods are ridge & mound while the different rates of phosphorus fertilizers are 0, 30, 60, 90 and 120 kg P2O5/ha in triple superphosphate (46% P2O5) form. Factorial experiment was used and treatments were arranged in a Randomized Complete Block Design with three replications. All the treatments were supplemented by 30 kg N/ha in the form of Urea (46% N). Results of this study indicated that plant growth was not significantly affected by tillage, but root yield was affected significantly with ridging produced the highest root yield. Further, highest growth and yield was observed from the 60 kg P2O5/ha treatment.

The aim of the study was to evaluate the effect of different rates of nitrogen (0, 10, 20, 30 and 40 kg N/ha) and phosphorus (0, 15, 30 and 45 kg P2O5/ha) fertilizers application on growth and yield performance of cowpea (variety Asontem). A factorial experiment was conducted in randomized complete block design with three replicates at the plantation site of Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, Ghana in the major cropping season of 2014. No significant effect of N and P fertilizer application on cowpea growth and yield was reported in present study. It is thus recommended that there is no need to apply N to cowpea planted in the same fertility status fields as in the present experimental site. Further studies required to be conducted with higher P rates.

Chicken manure (CM) carbonization is an efficient waste control method that converts manure into an agriculturally useful amendment. However, the recommended temperature range of 300–500 °C has led to confounding results on the maintenance of the nitrogen (N) supply ability of CM after carbonization, and thus requires further investigation. The objective of this study was to identify an upper limit (threshold) temperature to guide the carbonization of CM in order to ensure that the good N supply ability of the manure after carbonization is preserved. CM was carbonized at 350, 375, 400, 425, 450, and 475 °C. Afterwards, chemical properties, surface functional groups, N speciation, N supply ability, and their relationships were investigated. The results indicated that the N supply ability of CM carbonized at 350–375 °C was comparable to the N supply ability of CM, which is possibly due to the minute alteration of the chemical properties, surface functionality, and N speciation that occurred in CM at these temperatures. At ≥400 °C, the N supply ability of CM was significantly reduced due to the increasing alterations of the chemical makeup as heating temperature increased. For sustainable maintenance of the good N supply ability of CM after carbonization, the manure should not be carbonized above 375 °C.