Rice seed quality as influenced by storage duration and package type in Cameroon

The study aimed at evaluating the changes in rice seed quality as a function of storage duration and package type through characterization of seed quality determinants. Two rice varieties NERICA8 and NERICAL56) were measured into four package types (nylon bag, polyethylene bag, jute bag, and paper bag) and stored in a storage room of average relative humidity and temperature of 80% and 26 °C respectively. Standard methods of evaluating seed quality applicable to paddy were used. The quality parameters showed variability across the package types and storage duration. Remarkable changes were observed in the germination rate and insect damaged grains with slight changes in the number of colored grains, moisture content, and grain weight during the sampling intervals. The quantity of insect damage grains increased while germination rate decreased continuously during the entire experimental period. At three months of storage, the quantity of insect damage grains increased in all the bags for NERICA8 (0.1 g - 3.73 g) and was so for NERICAL56 only in the jute (0.15 g - 3.43 g) and paper (0.1 g - 3.13 g) bags at p<0.05 level of significance. Germination rate had reduced in all the bags below the minimum seed certification standard (MSCS) of 85%, reaching values of 53% and 51% for NERICA8 and NERICAL56 respectively in the polyethylene bag. Insect damage was least in the polyethylene bag (1.73 g) and highest in the jute (3.73 g) and paper (3.43 g) bags. NERICA8 was more pruned to insect damage as high values were observed at one month of storage but observed for NERICAL56 only at two months of storage. In addition, the number of colored grains was higher in the polyethylene and nylon bags compared to the jute and paper bags. From these results, a huge decrease in the quality of rice seeds occurred in the nylon and polyethylene bags. The observed high germination rate associated with insect infestation in the jute and paper bags suggest that if seeds in these bags are treated with insecticides, germination rate could improve to values around the MSCS even after three months of storage.Keywords: Seed quality, NERICA, germination, insect damage

Mucuna pruriens differentially affect maize yields in three soils of Kakamega District

Maize production in smallholder farming systems in Kenya is largely limited by low soil fertility. As mineral fertilizer is expensive, green manuring using leguminous cover crops could be an alternative strategy for farmers to enhance farm productivity. However, due to variability in soil type, the effects of green manure are likely to differ with farms. This study was conducted in three contrasting soils in Kakamega District, Kenya, to evaluate Mucuna pruriens on (i) biomass and nitrogen fixation (15N natural abundance) and (ii) the effects on maize yields over two cropping seasons. Mucuna at 6 weeks accumulated 1-1.3 Mg ha-1 of dry matter and 33-56 kg ha-1 nitrogen of which approximately 70% was nitrogen derived from the atmosphere (Ndfa). Maize yield increased by 0.5-2 Mg ha-1, 0.7-2 Mg ha-1 and 1.5-4 Mg ha-1 with Mucuna, farmyard manure and mineral fertilizer use, respectively, and the response was stronger in Nitisol than in Acrisol or Ferralsol. We concluded that green manuring using Mucuna seem promising in enhancing soil fertility and maize yields in Kakamega, provided soil conditions and rainfall are suitable.Keywords: Acrisol, Ferralsol, green manure, Nitisol, nitrogen fixatio