Soil fertility transience in the region of Masako in Democratic Republic (RD) of Congo remains a major challenge to sustainable agricultural production. Recently, biochar application as soil amendment has attracted attention of the people across the world owing to its potential to improve soil physicochemical properties, crop yield and carbon sequestration into the soil. A study was conducted in Masako to analyze the use of charcoal (biochar) as soil amendment and assess its effects on soil chemical performance and some biophysical parameters of maize crop. The experiment was set up using randomized complete block design with three replications of three treatments comprising ½ kg of sieved (small-sized particulate) charcoal per m 2 (C 1 ), 1 kg of sieved charcoal per m 2 (C 2 ) and control group without charcoal (C 0 ). Data were subjected to analysis of variance, Pearson's phenotypic correlation and regression analyses using genstat 12 th edition. The results of the analysis of variance showed non-significant variation for most physicochemical properties of soil and maize phenotypic traits, indicating that treatments had the same effects on soil composition suggesting that there was no clear impact of charcoal amendment as applied except for phosphorus content and collar diameter of the maize crop which were significantly (P ≤ 0.047 and P ≤ 0.043 respectively) influenced by the treatments. The results indicated that biochar improved the soil phosphorus availability by up to 72% as accounted for by the linear contribution of the treatment C 2 indicating that biochar could be recommended for use in soil with low level of phosphorous.

Groundnut leaf miner (GLM) [Aproaerema modicella (Deventer)] is a serious problem for soybean cultivation in Uganda causing yield losses of up to 100%. The use of soybean [Glycine max (L.) Merr.] cultivars resistant to GLM attack is an important strategy in the integrated pest management program. The aim of this study was to determine the environment × genotype interaction influence on the soybean resistance traits to GLM attack. Eighteen soybean genotypes were evaluated for resistance to GLM attack. The experiment was set up using randomized complete block design replicated three times under natural pest infestation in Budaka (Eastern) and Arua (Northern) districts in Uganda. Data were subjected to analysis of variance, Pearson's phenotypic correlation and cluster analysis. Highly significant (p < 0.001) differences among the genotypes were recorded for all the studied traits, except the number of pupae per plant which was significant (p < 0.05). GLM incidence and severity had significant negative correlations with rainfall and relative humidity. However, there were significant positive correlations between minimum temperature and GLM incidence as well as severity for most of the genotypes. Soybean genotypes VI046160 and VI046167 could be used as parents in breeding for resistance to GLM pest. Areas with high rainfall and humidity would be recommended for soybean production to minimize infestation by GLM.

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