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.

No abstract

No abstract

No abstract

Plants take up nitrogen (N) both day and night. The diurnal variation in N uptake results from interactions between aboveground and belowground tissues. We examined the long-term effects of interrupted N supply (day only or night only) under hydroponic conditions to test whether plant acclimatisation response to the interrupted N supply differs by day or night. Seedlings experienced 32 days under daytime-fed (DF), night-time-fed (NF), or continuous (CT) N supply. The root N uptake rate (NUR) differed between DF and NF from day 3 of treatment, after which NUR was significantly increased (by up to 82%) in DF and NF plants. The increased NUR during each half-day did not fully compensate for lost access to N during the other half-day, resulting in lower N accumulation by the end of the treatment. The reduction was smaller in DF plants than NF plants. The underlying mechanism of diurnal variation of N uptake is discussed in terms of transpiration demand and gene expression in roots.