scholarly journals Soil nutrient adequacy for optimal cassava growth, implications on cyanogenic glucoside production: a case of konzo-affected Mtwara region, Tanzania

2018 ◽  
Author(s):  
Matema L.E. Imakumbili ◽  
Ernest Semu ◽  
Johnson M.R. Semoka ◽  
Adebayo Abass ◽  
Geoffrey Mkamilo
Keyword(s):  
Soil Nutrient ◽  
Optimal Growth ◽  
Cyanogenic Glucoside ◽  
Nutrient Adequacy ◽  
Nutrient Levels ◽  
Cyanide Intoxication ◽  
Very High ◽  
Soil Phosphorous ◽  
Cassava Varieties

AbstractSoils in areas affected by konzo (a cassava cyanide intoxication paralytic disorder) are predominantly infertile and probably unable to supply cassava the nutrients it needs to achieve optimal growth. The soil nutrient levels in these areas, could also be influencing cyanogenic glucoside production in cultivated cassava, however there is hardly any knowledge on this. An assessment of soil nutrient levels on cassava fields in konzo-affected areas was therefore carried out to determine their adequacy for optimal cassava growth and how this influences cassava cyanogenic glucoside production. Konzo-affected Mtwara region, in Tanzania, was used as a case study area. Correlations between total hydrogen cyanide (HCN) levels in cassava roots and various soil nutrient levels on cassava fields were carried out and relationships between cyanide intoxication and soil nutrient levels on fields from which toxic cassava roots had been harvested were also investigated. The results showed that cassava grows under conditions of severe nutrient stress in the region. Soil nutrients found to be deficient on most fields, like potassium (mean = 0.09, SD = 0.05 cmol/kg), magnesium (mean = 0.26, SD = 0.14 cmol/kg) and zinc (mean = 1.34, SD = 0.26 mg/kg), are known to reduce cyanogenic glucoside levels in cassava roots when adequate in soils. Cyanogenic glucoside levels in cassava roots however increased by high levels soil phosphorous (rs = 0.486, p = 0.026 for all varieties) and sulphur (rs = 0.593, p = 0.032 and rs = 0.714, p = 0.047; for bitter and sweet cassava varieties, respectively) on these soils. The likelihood of cassava cyanide intoxication was also increased on fields with high pH and iron levels. High levels of sulphur and phosphorus, to very high levels of iron occurred on some fields. How soil nutrient supply influences cassava cyanogenic glucoside production in the konzo-affected areas was established.

scholarly journals Cyanogenic glucoside production in cassava: The comparable influences of varieties, soil moisture content and nutrient supply

2019 ◽  
Author(s):  
Matema L.E. Imakumbili ◽  
Ernest Semu ◽  
Johnson M.R. Semoka ◽  
Adebayo Abass ◽  
Geoffrey Mkamilo
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Fertility ◽  
Soil Moisture Content ◽  
Soil Nutrient ◽  
Moisture Stress ◽  
Nutrient Supply ◽  
Cyanogenic Glucoside ◽  
Moisture Conditions ◽  
Cassava Varieties

AbstractVarieties and soil moisture content are the two agronomic factors mostly pointed out as influencers of cyanogenic glucoside production in cassava. The role of soil nutrient supply is however often overlooked or minimised, despite its known influence on cyanogenic glucoside production. A pot experiment was hence carried out to determine whether soil nutrient supply had an equal influence on cyanogenic glucoside production in cassava, as varieties and soil moisture content. The cassava varieties, Kiroba (a sweet cassava variety) and Salanga (a bitter cassava variety), were used in the experiment, together with three soil moisture treatments that respectively induced severe moisture stress, moderate moisture stress and no moisture stress (optimal soil moisture conditions where plants were kept well-watered). The soil nutrient treatments used depicted conditions of low (no fertiliser), moderate (25 N mg, 5 P mg, 25 K mg /kg) and high (25 N mg, 5 P mg, 25 K mg /kg) nutrient supply. A sole K treatment was also included (25 K mg/kg). Total hydrogen cyanide (HCN) levels in cassava leaves were used to indicate the effects of the three factors on cyanogenic glucoside production. The results of the study showed that nutrient supply had a significantly (p < 0.001) equal influence on cyanogenic glucoside production, as varieties (p < 0.001) and soil moisture content (p < 0.001). Cyanogenic glucoside production was however found to be differently influenced by soil moisture content (M) and nutrient supply (N) in both Salanga (M×N, p = 0.002) and Kiroba (M×N, p < 0.001). Leaf HCN levels of unfertilised Salanga and Kiroba were respectively increased by 1.8 times and 2.7 times their levels under optimal soil moisture conditions. Thus, under severe moisture stress, low soil fertility was found to have an increasing effect on leaf HCN levels in both varieties. A high supply of N, P and K, however also had an increasing effect on leaf HCN in both varieties regardless of soil moisture conditions. Leaf HCN levels in Salanga ranged from 95.5 mg/kg to 334.5 mg/kg and in Kiroba they ranged from 39.3 mg/kg to 161.5 mg/kg, on a fresh weight basis. The study managed to demonstrate that soil fertility had an equally important influence on cyanogenic glucoside production, just like varieties and soil moisture content. The study also showed that the effects of nutrient supply on cyanogenic glucoside production in various cassava varieties is dependent on changes in soil moisture content and vice versa.

scholarly journals Soil nutrient adequacy for optimal cassava growth, implications on cyanogenic glucoside production: A case of konzo-affected Mtwara region, Tanzania

PLoS ONE ◽  
2019 ◽  
Vol 14 (5) ◽  
pp. e0216708 ◽  
Author(s):  
Matema L. E. Imakumbili ◽  
Ernest Semu ◽  
Johnson M. R. Semoka ◽  
Adebayo Abass ◽  
Geoffrey Mkamilo
Keyword(s):  
Soil Nutrient ◽  
Cyanogenic Glucoside ◽  
Nutrient Adequacy

scholarly journals Farmers’ perceptions on the causes of cassava root bitterness in konzo-affected areas of Mtwara Region, Tanzania

2018 ◽  
Author(s):  
Matema L.E. Imakumbili ◽  
Ernest Semu ◽  
Johnson M.R. Semoka ◽  
Adebayo Abass ◽  
Geoffrey Mkamilo
Keyword(s):  
Water Stress ◽  
Management Practices ◽  
Bitter Taste ◽  
Spastic Paraparesis ◽  
Cyanogenic Glucoside ◽  
Cassava Root ◽  
Number Of Factors ◽  
Bitter Cassava ◽  
Cassava Varieties

AbstractThe agronomic factors influencing increased cyanogenic glucoside levels, particularly in bitter cassava varieties during periods without water stress, in areas where konzo (a cassava cyanide related paralytic disorder also called spastic paraparesis) persists, are hardly known. However, through their assessment of bitter taste, farmers may have noticed factors unrelated to water stress and variety type that additionally influence cassava root cyanogenic glucoside content in these environments. Bitterness in cassava is usually associated with high cyanogenic glucoside levels. Using some konzo-affected areas in Mtwara region of Tanzania as a case study, a survey was thus carried out to identify the factors, hitherto overlooked, that may additionally influence cyanogenic glucoside levels in cassava. A total of 120 farmers were interviewed. A number of factors unrelated to water stress and variety type that could be additionally influencing cyanogenic glucoside production in cassava plants were mentioned. The mentioned factors included nutrient poor soils, plant age at harvest, weeds, piecemeal harvesting, and branch pruning; the factors, respectively, constituted 14.2%, 7.5%, 0.8%, 0.8%, and 0.8% of the total responses given. The revealed factors constitute permanent environmental characteristics and commonly used crop management practices by farmers living in konzo-prone Mtwara region of Tanzania that could be additionally resulting in high cyanogenic glucoside levels in cassava, regardless of water stress.

Populations Dynamics of Soybean Insect Pests vs. Soil Nutrient Levels

Crop Science ◽  
1991 ◽  
Vol 31 (6) ◽  
pp. 1629-1633 ◽  
Author(s):  
J. E. Funderburk ◽  
I. D. Teare ◽  
F. M. Rhoads
Keyword(s):  
Insect Pests ◽  
Soil Nutrient ◽  
Nutrient Levels ◽  
Populations Dynamics

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

Within-site drivers for soil nutrient variability in plantation forests: A case study from dry sub-humid New Zealand

CATENA ◽  
2021 ◽  
Vol 200 ◽  
pp. 105149
Author(s):  
Serajis Salekin ◽  
Mark Bloomberg ◽  
Justin Morgenroth ◽  
Dean F. Meason ◽  
Euan G. Mason
Keyword(s):  
New Zealand ◽  
Soil Nutrient ◽  
Plantation Forests ◽  
Nutrient Variability

scholarly journals A Raster-Based Subdividing Indicator to Map Urban Heat Vulnerability: A Case Study in Sydney, Australia

2018 ◽  
Vol 15 (11) ◽  
pp. 2516 ◽  
Author(s):  
Wei Zhang ◽  
Phil McManus ◽  
Elizabeth Duncan
Keyword(s):  
High Heat ◽  
The Past ◽  
Urban Heat ◽  
Research Gap ◽  
Heat Vulnerability ◽  
Very High ◽  
Flexible Model ◽  
General Indicator ◽  
Sydney Australia

Assessing and mapping urban heat vulnerability has developed significantly over the past decade. Many studies have mapped urban heat vulnerability with a census unit-based general indicator (CGI). However, this kind of indicator has many problems, such as inaccurate assessment results and lacking comparability among different studies. This paper seeks to address this research gap and proposes a raster-based subdividing indicator to map urban heat vulnerability. We created a raster-based subdividing indicator (RSI) to map urban heat vulnerability from 3 aspects: exposure, sensitivity and adaptive capacity. We applied and compared it with a raster-based general indicator (RGI) and a census unit-based general indicator (CGI) in Sydney, Australia. Spatial statistics and analysis were used to investigate the performance among those three indicators. The results indicate that: (1) compared with the RSI framework, 67.54% of very high heat vulnerability pixels were ignored in the RGI framework; and up to 83.63% of very high heat vulnerability pixels were ignored in the CGI framework; (2) Compared with the previous CGI framework, a RSI framework has many advantages. These include more accurate results, more flexible model structure, and higher comparability among different studies. This study recommends using a RSI framework to map urban heat vulnerability in the future.

scholarly journals Soil Nutrient Status of Brahmaputra Floodplain Area in Tangail Sadar Upazila for Agricultural Uses

2016 ◽  
Vol 8 (2) ◽  
pp. 11-14
Author(s):  
MAM Hossen ◽  
SA Lira ◽  
MY Mia ◽  
AKMM Rahman
Keyword(s):  
Soil Nutrient ◽  
Nutrient Status ◽  
Available Phosphorus ◽  
Soil Nutrient Status ◽  
Fe Content ◽  
P Content ◽  
Zn Content ◽  
Floodplain Area ◽  
Very High ◽  
Brahmaputra Floodplain

Soil samples from high land, medium high land, medium low land and low land of Brahmaputra Floodplain area showed that pH of the soils were slightly acidic; organic matter (OM) content was medium; total nitrogen (N), available potassium (K) and boron (B) content were low; available phosphorus (P) content was very low; available sulfur (S) and calcium (Ca) content were medium to very high; magnesium (Mg) and zinc (Zn) content were low to optimum; copper (Cu), manganese (Mn) and iron (Fe) content were very high suggesting the fact that soils of this area is moderately suitable for agricultural uses.J. Environ. Sci. & Natural Resources, 8(2): 11-14 2015

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