Declining yields in oil palm fresh fruit bunch (FFB) have been recorded over the past years in the coastal lowlands of southwest Cameroon and current actual yields are very low (<12 t FFB ha<sup><span styl...Declining yields in oil palm fresh fruit bunch (FFB) have been recorded over the past years in the coastal lowlands of southwest Cameroon and current actual yields are very low (<12 t FFB ha<sup><span style="white-space:nowrap;">−</span>1</sup><span style="white-space:nowrap;">•</span>yr<sup><span style="white-space:nowrap;">−</span>1</sup>) compared to the potential yields (25 t FFB ha<sup><span style="white-space:nowrap;">−</span>1</sup><span style="white-space:nowrap;">•</span>yr<sup><span style="white-space:nowrap;">−</span>1</sup>). One of the problems limiting optimum oil palm production is lack of detailed pedological information to guide plantation establishment and management. A land suitability evaluation was carried out for some major oil palm producing areas of southwest Cameroon to identify land qualities limiting optimal production. Thirteen sites (9 with sedimentary parent materials and 4 with volcanic parent material) were evaluated using a parametric method. Results indicate that climate was not a major limiting factor for oil palm production in coastal plains of southwest Cameroon. However, soil physical characteristics (mainly clayey texture and poor drainage) and soil fertility constitute limitations to oil palm production. Specifically, limitations in cation exchange capacity (CEC), base saturation (BS), organic carbon (OC) and pH were slight to moderate while K mole fraction was the most severe and the most limiting in all the sites. The fertility limitations were more pronounced in soils derived from sedimentary parent materials where 33% had limitations caused by soil pH and OC compared to none for volcanic soils. In addition, 77.8% of sedimentary soils had limitations caused by CEC compared to 25% for volcanic soils. Considering the overall suitability, soils derived from volcanic parent materials were potentially more suitable for oil palm cultivation ((S3)—50%, (S2)—50%) compared to sedimentary soils ((N)—11%, (S3)—78% and (S2)—11%). Based on the suitability classes of the different soils derived from dissimilar parent materials, appropriate site-specific soil management is needed to improve oil palm yields, especially with emphasis on K fertilization and improved soil water management. Plantation management in coastal plains of South West Cameroon therefore should factor in differences in soil parent material.展开更多
Moringa oleifera is a multipurpose tree used to remedy problems related to food insecurity and soil fertility degradation. Proper husbandry of this crop is contingent on the use of seedlings of good quality. This stud...Moringa oleifera is a multipurpose tree used to remedy problems related to food insecurity and soil fertility degradation. Proper husbandry of this crop is contingent on the use of seedlings of good quality. This study aimed at assessing the germination and early seedling growth with different soaking durations and substrates composition. The seeds were obtained from the Far North region of Cameroon. A randomized complete block design with three replications was used. Two factors were tested;soaking duration with 4 treatment levels of 0 day, 4 days, 8 days and 12 days and substrates with 8 treatment levels: 100% soil, 75% soil + 25% poultry manure (PM), 50% soil + 50% PM, 25% soil + 75% PM, 100% sand, 75% sand + 25% PM, 50% sand + 50% PM and 25% sand + 75% PM. Germinated seeds and growth parameters were collected after every 5 days. The results showed that soaking duration and substrate composition influence germination and initial development of M. oleifera (p ≤ 0.05). At 25 days after soaking (DAS), soaking durations of 0 day (68.7%) and 8 days (53.1%) showed the highest germination percentages while seeds soaked for 12 days occupied the least position with 37.5%. At the same time, 75% soil + 25% PM (68.7%), 100% sand (64.5%) and 100% soil (60.5%) with the unsoaked seeds showed the highest germination percentages. The least germination percentages were represented by 50% sand + 50% PM and 25% sand + 75% PM with 35.5% and 27%, respectively. Unsoaked seeds with the substrates of 50% soil + 50% PM are the best practice for M. oleifera seedling production in the nursery.展开更多
Land suitability assessment (LSA) is an essential step in the process of determining environmental limits for sustainable crop production. Up to date, studies on LSA for crop production in Cameroon have been based on ...Land suitability assessment (LSA) is an essential step in the process of determining environmental limits for sustainable crop production. Up to date, studies on LSA for crop production in Cameroon have been based on empirical methods which are limited as they consider similar singnificance levels for all evaluation criteria and do not consider the interrelationships of criteria in the best-fit models. In the present study a qualitative land suitability evaluation by an integrated multi-criteria decision-making (MCDM) approach and geographic information system (GIS) was tested to assess and map suitable land units for maize (Zea mays L) production in Cameroon Western highland. Eight environmental criteria identified as the most relevant for maize production in the area of interest (AOI) saw their thematic maps prepared using ArcGIS 10.8. The relationship between criteria was considered by the DEMATEL method. The criteria were weighted using the ANP method. Thereafter, the land suitability map was obtained using the weighted overlay analysis (WOA) in ArcGIS. The results obtained indicated that slope has the highest specific weight and consequently the greatest influence on land suitability for maize production in the locality. The land suitability map generated showed that Foumbot’s agricultural land suitability for maize production varies from very high to marginally suitable (99% of the surface area). Specifically, 11% (8056 ha) is very highly suitable, 29% (21,119 ha) is highly suitable, 38% (27,405 ha) are moderately suitable and 20% (14,422 ha) are marginally suitable. The remaining 1% that falls under non suitable class represents 606 ha and is located on the steep slopes around the Mount Mbappit. The kappa analysis reveals a total overall accuracy of 78.67% and a kappa value of 0.7256 with an asymptotic error of 0.058 which is good. Then the model used in this research is highly recommended for future land evaluation works in Cameroon and similar ecosystems around the world.展开更多
Clay minerals constitute an important component of the soil system and knowledge of their role in soil fertility is imperative for sustainable soil management and productivity. The aim of this work is to overview the ...Clay minerals constitute an important component of the soil system and knowledge of their role in soil fertility is imperative for sustainable soil management and productivity. The aim of this work is to overview the influence of clay minerals on some major soil fertility attributes. The rationale for carrying out this work is that most soil fertility studies rarely incorporate soil mineralogy. Clay minerals, through their physical and chemical properties, affect soil fertility by controlling nutrient supplies and availability, through the sequestration and stabilization of soil organic matter, by controlling soil physical properties through microaggregate formation, by influencing soil acidity and controlling soil microbial population and activity. The main processes involved in these relationships are dissolution-precipitation and adsorption-desorption processes, alongside mechanisms involving the formation of short-range-ordered phases. Although the determination of soil mineralogical properties is very costly and time-consuming, information about a soil’s mineralogy is imperative for a holistic understanding and proper management of soil fertility. Therefore, the development of rapid, low-cost, reliable and efficient techniques of soil mineralogical analysis, directly applicable to soil fertility investigations, constitutes a major challenge. Also, future research should investigate the relationships between clay minerals and soil nitrogen vis-à-vis sequestration and stabilization. Lastly, clay minerals should be considered in studies dealing with soil quality assessment, especially in the choice of soil quality indicators.展开更多
The growth of Maesopsis under the influence of various geomorphic surfaces was followed within a period of 70 months. Young plants of two months old were transplanted into 70 × 70 × 70 cm holes under natural...The growth of Maesopsis under the influence of various geomorphic surfaces was followed within a period of 70 months. Young plants of two months old were transplanted into 70 × 70 × 70 cm holes under natural conditions (no inputs such as manure and other amendments). A randomized complete block design was set up for the experiment, alongside a control, and growth parameters followed (height and collar circumference). Three blocks with different geomorphic surfaces were put in place for the experiment (upper slope or block 1, middle slope or block 2 and foot slope or block 3). Results of the experiment indicated that geomorphic surface had a significant effect on height but not on collar circumference. Plant height increased progressively from upper slope to foot slope;less tall trees were found at the upper slope, while the tallest trees were found at the foot slope. After 70 months, maximum average height attained by plants for the experiment was 1228.3 cm, observed in block 3 (foot slope), significant at 0.05 confidence level with respect to geomorphic surface. In blocks 1 and 2 (upper slope and middle slope), maximum average heights attained were 798.5 and 937.5 cm, respectively and were shown to be statistically equal at 0.05 confidence level. Geomorphic surface had no effect on collar circumference. Maximum average collar circumferences attained after 70 months were 62.8 cm (observed at the upper slope), 61.3 cm (observed at the middle slope) and 76.3 cm (observed at the foot slope) and the various collar circumferences were shown to be statistically the same at 0.05 confidence level. For the control, maximum height attained after 70 months was 1240 cm (observed at the foot slope). At the upper slope and middle slope, maximum average heights were respectively, 800 cm and 905 cm, and were statistically equal at the 0.05 confidence level but different from the foot slope value of 1240 cm. Maximum average collar circumference was observed at the foot slope (76.3 cm), while circumferences of 62.8 cm and 61.3 cm were respectively observed at the upper and middle slopes. In the control, collar circumference was shown to be statistically equal at the upper and middle slopes but different from that at the foot slope at 0.05 confidence level. Correlations between growth parameters were more explained for the control than for the experiment. Increasing plant height was associated with decreasing percent slope (at a p-value of 0.05) corresponding to increasing soil depth favoring root exploration and soil and water retention. Profile modification enhanced plant growth and enabled the cultivation of trees on all geomorphic surfaces.展开更多
Knowledge on soil properties likely to influence P sorption in tephra soils is very important for sustainable management of available P. Sorption studies on six tephra soils were conducted to relate P sorption to soil...Knowledge on soil properties likely to influence P sorption in tephra soils is very important for sustainable management of available P. Sorption studies on six tephra soils were conducted to relate P sorption to soil characteristics in order to identify those with potential influence on P sorption. Four equilibrium-based sorption models commonly encountered in soil studies (Langmuir, Freundlich, Temkin, and Van Huay) were used to describe P sorption in the soils. P sorption was determined by measuring the residual P content of a clarified equilibrating solution of 0.02 N KCl containing varying concentrations (0, 5, 10, 15, 30, 40, 50, 60, 80, and 100 mg/L) of P as KH2PO4 after mixing with 1 g of soil in duplicates for 16 hours at 25°C. Maximum amount of P sorbed for the varying P concentrations used ranged from 2080 to 5402 mg/kg with a potential for greater P sorption maxima at higher P solution concentrations. P sorption in these soils was best described by the Langmuir and Freundlich models. Allophane and ferrihydrite are the principal species controlling the high P sorption in these soils. pH-NaF proved to be a potentially reliable test for assessing the presence of allophanic materials and thus for estimating P sorbed. This work would guide both effective and efficient P fertilizer management with economic implications for both the study area and similar environments.展开更多
文摘Declining yields in oil palm fresh fruit bunch (FFB) have been recorded over the past years in the coastal lowlands of southwest Cameroon and current actual yields are very low (<12 t FFB ha<sup><span style="white-space:nowrap;">−</span>1</sup><span style="white-space:nowrap;">•</span>yr<sup><span style="white-space:nowrap;">−</span>1</sup>) compared to the potential yields (25 t FFB ha<sup><span style="white-space:nowrap;">−</span>1</sup><span style="white-space:nowrap;">•</span>yr<sup><span style="white-space:nowrap;">−</span>1</sup>). One of the problems limiting optimum oil palm production is lack of detailed pedological information to guide plantation establishment and management. A land suitability evaluation was carried out for some major oil palm producing areas of southwest Cameroon to identify land qualities limiting optimal production. Thirteen sites (9 with sedimentary parent materials and 4 with volcanic parent material) were evaluated using a parametric method. Results indicate that climate was not a major limiting factor for oil palm production in coastal plains of southwest Cameroon. However, soil physical characteristics (mainly clayey texture and poor drainage) and soil fertility constitute limitations to oil palm production. Specifically, limitations in cation exchange capacity (CEC), base saturation (BS), organic carbon (OC) and pH were slight to moderate while K mole fraction was the most severe and the most limiting in all the sites. The fertility limitations were more pronounced in soils derived from sedimentary parent materials where 33% had limitations caused by soil pH and OC compared to none for volcanic soils. In addition, 77.8% of sedimentary soils had limitations caused by CEC compared to 25% for volcanic soils. Considering the overall suitability, soils derived from volcanic parent materials were potentially more suitable for oil palm cultivation ((S3)—50%, (S2)—50%) compared to sedimentary soils ((N)—11%, (S3)—78% and (S2)—11%). Based on the suitability classes of the different soils derived from dissimilar parent materials, appropriate site-specific soil management is needed to improve oil palm yields, especially with emphasis on K fertilization and improved soil water management. Plantation management in coastal plains of South West Cameroon therefore should factor in differences in soil parent material.
文摘Moringa oleifera is a multipurpose tree used to remedy problems related to food insecurity and soil fertility degradation. Proper husbandry of this crop is contingent on the use of seedlings of good quality. This study aimed at assessing the germination and early seedling growth with different soaking durations and substrates composition. The seeds were obtained from the Far North region of Cameroon. A randomized complete block design with three replications was used. Two factors were tested;soaking duration with 4 treatment levels of 0 day, 4 days, 8 days and 12 days and substrates with 8 treatment levels: 100% soil, 75% soil + 25% poultry manure (PM), 50% soil + 50% PM, 25% soil + 75% PM, 100% sand, 75% sand + 25% PM, 50% sand + 50% PM and 25% sand + 75% PM. Germinated seeds and growth parameters were collected after every 5 days. The results showed that soaking duration and substrate composition influence germination and initial development of M. oleifera (p ≤ 0.05). At 25 days after soaking (DAS), soaking durations of 0 day (68.7%) and 8 days (53.1%) showed the highest germination percentages while seeds soaked for 12 days occupied the least position with 37.5%. At the same time, 75% soil + 25% PM (68.7%), 100% sand (64.5%) and 100% soil (60.5%) with the unsoaked seeds showed the highest germination percentages. The least germination percentages were represented by 50% sand + 50% PM and 25% sand + 75% PM with 35.5% and 27%, respectively. Unsoaked seeds with the substrates of 50% soil + 50% PM are the best practice for M. oleifera seedling production in the nursery.
文摘Land suitability assessment (LSA) is an essential step in the process of determining environmental limits for sustainable crop production. Up to date, studies on LSA for crop production in Cameroon have been based on empirical methods which are limited as they consider similar singnificance levels for all evaluation criteria and do not consider the interrelationships of criteria in the best-fit models. In the present study a qualitative land suitability evaluation by an integrated multi-criteria decision-making (MCDM) approach and geographic information system (GIS) was tested to assess and map suitable land units for maize (Zea mays L) production in Cameroon Western highland. Eight environmental criteria identified as the most relevant for maize production in the area of interest (AOI) saw their thematic maps prepared using ArcGIS 10.8. The relationship between criteria was considered by the DEMATEL method. The criteria were weighted using the ANP method. Thereafter, the land suitability map was obtained using the weighted overlay analysis (WOA) in ArcGIS. The results obtained indicated that slope has the highest specific weight and consequently the greatest influence on land suitability for maize production in the locality. The land suitability map generated showed that Foumbot’s agricultural land suitability for maize production varies from very high to marginally suitable (99% of the surface area). Specifically, 11% (8056 ha) is very highly suitable, 29% (21,119 ha) is highly suitable, 38% (27,405 ha) are moderately suitable and 20% (14,422 ha) are marginally suitable. The remaining 1% that falls under non suitable class represents 606 ha and is located on the steep slopes around the Mount Mbappit. The kappa analysis reveals a total overall accuracy of 78.67% and a kappa value of 0.7256 with an asymptotic error of 0.058 which is good. Then the model used in this research is highly recommended for future land evaluation works in Cameroon and similar ecosystems around the world.
文摘Clay minerals constitute an important component of the soil system and knowledge of their role in soil fertility is imperative for sustainable soil management and productivity. The aim of this work is to overview the influence of clay minerals on some major soil fertility attributes. The rationale for carrying out this work is that most soil fertility studies rarely incorporate soil mineralogy. Clay minerals, through their physical and chemical properties, affect soil fertility by controlling nutrient supplies and availability, through the sequestration and stabilization of soil organic matter, by controlling soil physical properties through microaggregate formation, by influencing soil acidity and controlling soil microbial population and activity. The main processes involved in these relationships are dissolution-precipitation and adsorption-desorption processes, alongside mechanisms involving the formation of short-range-ordered phases. Although the determination of soil mineralogical properties is very costly and time-consuming, information about a soil’s mineralogy is imperative for a holistic understanding and proper management of soil fertility. Therefore, the development of rapid, low-cost, reliable and efficient techniques of soil mineralogical analysis, directly applicable to soil fertility investigations, constitutes a major challenge. Also, future research should investigate the relationships between clay minerals and soil nitrogen vis-à-vis sequestration and stabilization. Lastly, clay minerals should be considered in studies dealing with soil quality assessment, especially in the choice of soil quality indicators.
文摘The growth of Maesopsis under the influence of various geomorphic surfaces was followed within a period of 70 months. Young plants of two months old were transplanted into 70 × 70 × 70 cm holes under natural conditions (no inputs such as manure and other amendments). A randomized complete block design was set up for the experiment, alongside a control, and growth parameters followed (height and collar circumference). Three blocks with different geomorphic surfaces were put in place for the experiment (upper slope or block 1, middle slope or block 2 and foot slope or block 3). Results of the experiment indicated that geomorphic surface had a significant effect on height but not on collar circumference. Plant height increased progressively from upper slope to foot slope;less tall trees were found at the upper slope, while the tallest trees were found at the foot slope. After 70 months, maximum average height attained by plants for the experiment was 1228.3 cm, observed in block 3 (foot slope), significant at 0.05 confidence level with respect to geomorphic surface. In blocks 1 and 2 (upper slope and middle slope), maximum average heights attained were 798.5 and 937.5 cm, respectively and were shown to be statistically equal at 0.05 confidence level. Geomorphic surface had no effect on collar circumference. Maximum average collar circumferences attained after 70 months were 62.8 cm (observed at the upper slope), 61.3 cm (observed at the middle slope) and 76.3 cm (observed at the foot slope) and the various collar circumferences were shown to be statistically the same at 0.05 confidence level. For the control, maximum height attained after 70 months was 1240 cm (observed at the foot slope). At the upper slope and middle slope, maximum average heights were respectively, 800 cm and 905 cm, and were statistically equal at the 0.05 confidence level but different from the foot slope value of 1240 cm. Maximum average collar circumference was observed at the foot slope (76.3 cm), while circumferences of 62.8 cm and 61.3 cm were respectively observed at the upper and middle slopes. In the control, collar circumference was shown to be statistically equal at the upper and middle slopes but different from that at the foot slope at 0.05 confidence level. Correlations between growth parameters were more explained for the control than for the experiment. Increasing plant height was associated with decreasing percent slope (at a p-value of 0.05) corresponding to increasing soil depth favoring root exploration and soil and water retention. Profile modification enhanced plant growth and enabled the cultivation of trees on all geomorphic surfaces.
文摘Knowledge on soil properties likely to influence P sorption in tephra soils is very important for sustainable management of available P. Sorption studies on six tephra soils were conducted to relate P sorption to soil characteristics in order to identify those with potential influence on P sorption. Four equilibrium-based sorption models commonly encountered in soil studies (Langmuir, Freundlich, Temkin, and Van Huay) were used to describe P sorption in the soils. P sorption was determined by measuring the residual P content of a clarified equilibrating solution of 0.02 N KCl containing varying concentrations (0, 5, 10, 15, 30, 40, 50, 60, 80, and 100 mg/L) of P as KH2PO4 after mixing with 1 g of soil in duplicates for 16 hours at 25°C. Maximum amount of P sorbed for the varying P concentrations used ranged from 2080 to 5402 mg/kg with a potential for greater P sorption maxima at higher P solution concentrations. P sorption in these soils was best described by the Langmuir and Freundlich models. Allophane and ferrihydrite are the principal species controlling the high P sorption in these soils. pH-NaF proved to be a potentially reliable test for assessing the presence of allophanic materials and thus for estimating P sorbed. This work would guide both effective and efficient P fertilizer management with economic implications for both the study area and similar environments.
