Simulation of Growth and Leaf Area Index of Quality Protein Maize Varieties in the Southwestern Savannah Region of the DR-Congo

Logistic and exponential approaches have been used to simulate plant growth and leaf area index (LAI) in different growing conditions. The objective of the present study was to develop and evaluate an approach to simulate maize LAI that expresses key physiological and phonological processes using a minimum entry requirement for Quality Protein maize (QPM) varieties grown in the southwestern region of the DR-Congo. Data for the development and testing of the model were collected manually in experimental plots using a non-destructive method. Simulation results revealed measurable variations between crop seasons (long season A and short season B) and between the two varieties (Mudishi-1 and Mudishi-3) for height, number of visible leaves, and LAI. For both seasons, Mudishi-3, a short stature variety was associated with expected stable yield based on simulation data. In general, the model simulated reliably all the parameters including the LAI. The LAI value for mudishi-1 was higher than that of Mudishi-3. There were significant differences among the model parameters (K, Ti, a, b, Tf) and between the two varieties. In all crop conditions studied and for the two varieties, the senescence rate (a) was higher, while the growth rate (b) was lower compared to the estimates based on the STICS model.

Agro-Ecological Adaptation and Participatory Evaluation of Multipurpose Tree and Shrub Legumes in Mid Altitudes of Sud-Kivu, D. R. Congo

Livestock is traditionally managed in mixed crop-livestock production systems in Sud-Kivu, D. R. Congo. Currently, livestock production is facing numerous constraints due to wars and insecurity in the country, with looting of animals, demographic pressure on natural resources, and lack of extension services. Multipurpose trees and shrubs with adequate forage quality could help overcome dry-season feed shortage. The objective of this research was to assess the agro-ecological adaptability of selected forage tree and shrub legumes combined with farmer participatory evaluation. The study was carried out at two distinct mid-altitude sites in Sud-Kivu. Trees and shrubs were planted randomly in eleven lines, with each species/accession consisting of nine plants split into three replications. Following a standardization cut after one year of growth, regular biomass harvests were performed every eight weeks during one year;Desmodium and Flemingia were cut at 0.5 m above soil surface, while Leucaena and Calliandra at 1 m. Before every harvest, plant height was measured and number of stems counted. Fresh leaf and stem biomass were weighted, sub samples dried and leaves analyzed for nutritive value. Results from agronomic evaluation show that Leucaena diversifolia ILRI 15551 and Leucaena leucocephala had the highest yield in the rainy season on fertile soil;during dry season, Leucaena diversifolia ILRI 15551 was superior. On poor soil, Flemingia macrophylla CIAT 17403 performed best in both seasons, however, its forage quality was relatively low. Forage tree and shrub legumes chosen by farmers were, in general, the same as those superior ones in agronomic evaluation.

Testing Agro-Ecological Adaptation of Improved Herbaceous Forage Legumes in South-Kivu, D.R. Congo

In tropical african countries where livestock is either reared in herds on natural grasslands or individuallly tethered to herds on natural or spontaneous vegetation, the productivity is low, especially during the dry season. Using improved forages could play an important role in both enhancing livestock production and improving soil fertility and preventing from soil erosion. Eleven herbaceous forage legumes previously tested in tropical South America and South Asia by CIAT were tested in South-Kivu, D. R. Congo. Across sites, Stylosanthes guianensis, Desmodium uncinatum, Centrosema molle and Canavalia brasiliensis had a highest yield, nowhere Vigna unguiculata adapted. Differencial plant adaptation occured, e.g. Clitoria ternatea being well adaptated only in the midlands with good soils, where the mean of dry mater leaf yield was higher. Farmer evaluation emphazied overall biomass production with preference in the highlands, farmers chose Desmodium uncinatum, Canavalia brasiliensis and Lablab purpureus 21603 and in the midlands Stylosanthes guianensis 11995 and Lablab purpureus 22759. Farmer evaluation confirmed the best yield fit herbaceous forage legumes.

Seric Calcium and Magnesium in Normal and Pre Eclamptic Pregnant Women: A Case-Control Study in Kinshasa, D R Congo

Goal: The present study aimed to determine the profile of seric calcium and magnesium in pre-eclamptic and eclamptic pregnant women of Kinshasa province in the Democratic Republic of Congo where preeclampsia is characterized not only by a high incidence, but also by a seasonal variation probably related to nutritional intake. Study Design: This is a case-control study that took place during the period from September 2014 to March 2015 in four quaternary and tertiary maternity hospitals in Kinshasa. A total of 113 healthy pregnant women (controls) and 112 pre-eclamptic and eclamptic pregnant women (cases) were included in this study. Seric calcium and magnesium were measured in all these gravidas by the principle of spectrophotometry with a HUMALYSER Primus semi-automaton. Results: The mean age of those gravidas was 26.8 ± 6.3 years (26.7 vs 26.9, p = 0.11). The majority of these gravidas were primiparous. The mean gestational age in both groups was 31.35 ± 0.9 weeks (32.1 vs 30.6, p = 0.21). The average seric calcium value was 4.47 ± 0.23 mEq /L in healthy pregnant women compared to 3.80 ± 0.71 mEq/l in pre-eclamptics (P 0.001). The mean of seric magnesium was 1.56 ± 0.15 mg/dL in healthy pregnant women compared to 1.20 ± 0.41 mg/dL in pre eclamptics (P 0.001). Seric calcium and magnesium values were low in the pre-eclamptic group and lower in the eclamptic group (P 0.001). Conclusion: This study establishes a relationship between the low concentration of seric calcium and magnesium with pre-eclampsia and eclampsia, which could be one of the determinants of the high prevalence and seasonality of the disease in Kinshasa.

Heavy Metal Levels and Potential Ecological Risks Assessed at an Agroecosystem Site in Tropical Region

The concentrations and distribution of thirteen metals and metalloids were investigated in soils, sediments, and two biological matrices (the fish Clarias gariepisnis and the earthworm Pontoscolex corethrurus) from the CECOMAF agroecosystem, in Kinshasa, Democratic Republic of the Congo, in order to assess the impact of anthropogenic activities. The results revealed high concentrations of heavy metals, such as Cu, Zn, As, Cd, Pb, and Hg all above values recommended by sediment quality guidelines and their probable effect levels on biota. According to the calculated Enrichment Factor, soil and sediments ranked from moderately to heavily polluted by Cu, Zn, Cd, Pb and Hg. The Contamination Degree and other ecological risk indices indicated very high contamination and very high ecological risks posed by Cd and Hg, respectively. The Geoaccumulation Index indicated that current metal concentrations in the agroecosystem originated from anthropogenic activities, while the Spearman correlation matrix values indicated that Hg could originate from different sources and pathways than the other metals. It was concluded that metals from unchecked anthropogenic activities have negatively impacted agricultural activities and fish production at the CECOMAF agroecosystem. Action to reduce the contamination level and the ecological risks by remediating and preventing metal pollution in the CECOMAF agroecosystem site is recommended.