Effects of tuber protion and time of harvesting on accumulation and partitioning of dry matter In water yam (Dioscorea alanta) minisett in Uyo, Southern Nigeria

The high cost of seed yam is a serious constraint to water yam production. Therefore a two-year field trial was conducted at the University of Uyo Teaching and Research Farm to evaluate dry matter accumulation and partitioning among various plant parts in water yam (Dioscorea alata L.) minisetts as influenced by portion of tuber planted and time of harvesting. The experiment was laid out in a randomised complete block design with a split-plot arrangement. The main-treatments were portions of tuber planted (head, middle and tail) and the sub-treatments were time of harvesting (90, 180 and 270 days after planting DAP). The results showed that portions of tuber planted had no significant effect on dry matter accumulation within leaves, vines, roots and tuber. Early in the season (i.e. 90 DAP), leaves, vines and roots collectively accounted for 67, 62 and 57% of the total plant dry matter for the head, middle, and tail portions, respectively; thereafter the dry matter content declined. However, as the plant matured, the partitioning ratios decreased for leaves, vines and roots, but increased for tubers. Similarly, dry matter accumulation differed significantly (

Yield response of soybeans to levels of nitrogen and potassium fertilizer in the humid tropics

A field trail was conducted at the University of Uyo Teaching and Research Farm in a high rainfall area of South eastern Nigeria to assess the yield response soybeans [ Glycine max (L.) Merrill ] to different levels of nitrogen and potassium fertilizers. The results showed that the number of pods/ plant, threshing percentage and gain yield (t/ha) were significantly influenced by nitrogen fertilizer application. Nitrogen applied at the rate of 45kg N/ha was more consistent in influencing soybean yield. Potassium on the other hand, significantly influenced number of branches/plant, number of pods per plant, 100 seed weight and grain yield. Beneficial range of doses of application of potassium was found to be 30 75kg/ha. Moreso, response of soybean to nitrogen was more at higher doses of potassium. Key Words: Yield Components, Glycine max, Levels of Fertilization, Threshing Percentage [Global Jnl Agric Res Vol.1(2) 2002: 101-110