Microhabitat variation in an African savanna: effects of woody cover and herbivores in Kenya

1989 ◽  
Vol 5 (1) ◽  
pp. 93-108 ◽  
Author(s):  
Nicholas J. Georgiadis

AbstractEffects of extreme livestock pressure on the abundance and distribution of a drought-deciduous shrub Sericocomopsis pallida, and effects of the shrub canopy on microclimate, soil fertility and grass production, were studied in savanna grasslands of southern Kenya. Canopy volume declined with increasing herbivore pressure, but shrub density was not systematically affected, suggesting strong resilience against destruction by herbivores. However, shrubs became more aggregated with increasing herbivory, suggesting that clumps of individuals are more resilient to destruction than are isolated individuals. Grass production was three times greater under the canopy of S. pallida than in the open. Comparisons of physical-chemical properties among soils derived from four microsites revealed far higher nutrient levels in sub-canopy soil than in soil derived from open ground between canopies, and radically different properties compared to soil heavily enriched with livestock dung and urine. Higher nutrient levels beneath the canopy most likely resulted from Utter decomposition.A pot experiment, designed to simulate shading and soil conditions in the field, showed that grass growth promotion was largely due to a substantial increase in soil fertility beneath the canopy of S. pallida, comparable to grass productivity in soil enriched with livestock excreta. However, this increase in sub-canopy grass production did not significantly increase regional grass layer production.

2001 ◽  
Vol 52 (3) ◽  
pp. 377 ◽  
Author(s):  
J. Jackson ◽  
A. J. Ash

To investigate the effects of eucalypt trees on pasture in open eucalypt woodlands of north-eastern Queensland, 2 common native pasture species, Chrysopogon fallaxand Heteropogon contortus, were grown in soil collected from under tree canopies and inter-canopy areas. These soils were collected from 2 localities that differed in soil fertility. The objective was to determine whether trees enhanced soil nutrient levels beneath their canopies and whether such changes affected pasture productivity and quality. It was hypothesised that tree effects would be greater when overall soil fertility was low. Shade and water stress treatments, which aimed to simulate field conditions, were also imposed to investigate their independent and interactive effects on plant growth. Chemical analyses showed that nutrient levels were higher in under-canopy soils, and plants grown in under-canopy soil produced 42% more biomass than plants in outside-canopy soil. This increase in biomass was significantly greater when the soil was from the low fertility site than from the high fertility site. Leaf quality, in terms of N and P concentration and dry matter digestibility (DMD), was generally higher in plants in under-canopy soil. Shading reduced plant root biomass but had no effects on above ground biomass or leaf quality. Water stress reduced above and below ground biomass and increased leaf quality. Shading and water stress effects were greater in plants in the more fertile soil types. Simulated ‘under-canopy’ plants (shaded, water-stressed plants in under-canopy soil) produced more biomass and had higher leaf N concentration and DMD than simulated ‘outside-canopy’ plants (unshaded, well-watered plants in outside-canopy soil). In a pastoral context, trees in tropical woodlands are generally considered in terms of their competitive effect on pasture productivity. This study has demonstrated that soil nutrient availability is enhanced under eucalypt canopies. The biomass results indicate that this effect is greater when overall soil fertility conditions are low. These enhanced soil nutrient conditions influence forage productivity and quality. Such positive benefits should be considered when management decisions are taken to remove or kill trees in eucalypt woodlands.


Author(s):  
Gebeyaw Tilahun Yeshaneh

The study was conducted at the Abuhoy Gara Catchment, which is located in the Gidan District of North Wello Zone. The aim of the study was to study farmers’ perceptions about the effect of farm land management practices and soil depth on the distribution of major soil physico-chemical properties in eroded soils of Aboy Gara watershed. To address this issue, semi-structured interviews were conducted in 64 households to gain insight into soil fertility management practices, local methods were used to assess the fertility status of a field, and perceived trends in soil fertility. Thirty-three farmers were then asked to identify fertile and infertile fields. According to farmers response, farmers’ fields were characterized as fertile where it comprise black color, cracks during dry season, good crop performance, vigorous growth of certain plants and presence of plants in a dry environment whereas the infertile is where it shows yellow/white and red colors, compacted soils, stunted plant growth, presence of rocks and stones and wilting or dying of crops in a hot environment. A total of eight indicators (soil color, texture, soil depth, topography, soil drainage, and distance from home, type of weeds grown and cultivation intensity) were found to be used by farmers to evaluate and monitor soil fertility. The results of administered questions showed that the principal indicators mentioned by farmers as very important were soil colour (82.8%), continuous cropping land (72.2%), soil texture (62.8%), distance from home (61%), type of weeds grown (56%), soil depth (55.6%), topography (51.1%), and soil drainage (28.7%) as very important. So, among sixty four interviewed farmers: deep soil (60 farmers), soils near to home (60 farmers), forest soil (59 farmers), smooth fine soil (59 farmers), black color soil (58 farmers) and gentle slope soil (57farmers) are categorized as fertile whereas 59, 57, 56, 55, and 44farmers said that Sandy/coarse soil, shallow soil depth, steep slope soils and yellow/white, red soils and continuously cultivated soils are infertile, respectively. The overall result showed that there was good agreement between farmers’ assessment of the soil fertility status of a field and a number of these indicators. The soil laboratory analysis also corresponded well with farmers’ assessment of soil fertility. Therefore, to design more appropriate research and to facilitate clear communication with farmers, researchers need to recognize farmers’ knowledge, perceptions about assessments of soil fertility. Because, as they included all soil factors affecting plant growth, farmers’ perceptions of soil fertility were found to be more long term day-to-day close practical experience finding than those of researchers.


2020 ◽  
pp. 80-88
Author(s):  
Beatrice Abanum Nduka ◽  
Olorunfemi Sunday Ojo Akanbi ◽  
Idrisu Mohammed ◽  
Seun Adewale Adeosun ◽  
Osasogie Ugioro ◽  
...  

A two-year experiment was conducted to study the response of manuring on growth and canopy development on three-year-old Cashew trees. The experiment was laid in a randomized complete block design, with three replications. Soil characteristics including the chemical and physical properties were analyzed before and after the experiments. Fecti-plus organic pelletized fertilizer was applied at different rates of 0,750.6 and 1,501.2 kg/ha-1 respectively around the circumference of the tree. Before the application, the fertilizer sample was also analyzed. Data collected were plant height, stem girth, canopy dynamics which includes: Canopy diameter, canopy radius, canopy spread (North-South and East-West directions), canopy volume, canopy ground cover and percentage ground cover. The results from the pre soil sample show a relatively low status but were significantly enhanced after the application of the pelletized organic fertilizer (Ferti-plus). The soil nutrient composition of Oc, Om, N, K, Na, Ca and Mg+ was significantly highest in the plots having 1,501.2 kg/ha-1 treatments. Generally, there was a significant increase in the soil nutrient with the addition of pelletized fertilizer in respective of the rate of application. Also the results on the canopy dynamic in terms of canopy volume, spread and diameter revealed better development with the use of 1501.2 kg/ha-1 pelletized fertilizer and significantly different to 750.6 kg/ha-1 and those in the no-manure (control)plots. Meanwhile, the use of pelletized organic fertilizer gave superior growth and canopy development. It also influenced the growth of the Cashew plants, as well as the physical and chemical properties of the soil status.


2015 ◽  
Vol 33 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Juan De la Cruz Jiménez ◽  
Juan Andrés Cardoso ◽  
David Arango-Londoño ◽  
Gerhard Fischer ◽  
Idupulapati Rao

As a consequence of global warming, rainfall is expected to increase in several regions around the world. This, together with poor soil drainage, will result in waterlogged soil conditions. <em>Brachiaria</em> grasses are widely sown in the tropics and, these grasses confront seasonal waterlogged conditions. Several studies have indicated that an increase in nutrient availability could reduce the negative impact of waterlogging. Therefore, an outdoor study was conducted to evaluate the responses of two <em>Brachiaria</em> sp. grasses with contrasting tolerances to waterlogging, <em>B. ruziziensis </em>(sensitive) and <em>B. humidicola</em> (tolerant), with two soil fertility levels. The genotypes were grown with two different soil fertilization levels (high and low) and under well-drained or waterlogged soil conditions for 15 days. The biomass production, chlorophyll content, photosynthetic efficiency, and macro- (N, P, K, Ca, Mg and S) and micronutrient (Fe, Mn, Cu, Zn and B) contents in the shoot tissue were determined. Significant differences in the nutrient content of the genotypes and treatments were found. An increase of redoximorphic elements (Fe and Mn) in the soil solution occurred with the waterlogging. The greater tolerance of <em>B. humidicola</em> to waterlogged conditions might be due to an efficient root system that is able to acquire nutrients (N, P, K) and potentially exclude phytotoxic elements (Fe and Mn) under waterlogged conditions.  A high nutrient availability in the waterlogged soils did not result in an improved tolerance for <em>B. ruziziensis</em>. The greater growth impairment seen in the <em>B. ruziziensis</em> with high soil fertility and waterlogging (as opposed to low soil fertility and waterlogging) was possibly due to an increased concentration of redoximorphic elements under these conditions.


Author(s):  
H. Haruna

Land use changes from forest into cultivated ecosystems result in negative impact on soil structure and quality. The purpose of this study was to determine effect of land use on soil quality in Afaka forest northern guinea savannah of Nigeria. Land use systems, including natural forest and cultivated land were identified. Eighteen (18) composite disturbed and undisturbed samples were collected from depth of 0-5 and 5-10 cm for analysis of pertinent soil properties in the laboratory using grid procedure. Most physical and chemical properties show relative variations in response to land use types and geomorphic positions. Results  indicate  that the soils had  high degree of weathering potentials, low  to moderate  bulk density at 0-5cm depth values between 1.42 to 1.49 Mg m-3 in  forest and  cultivated land, bulk density of  1.34 and 1.46 1.Mg m-3at 5 -1ocm depth   for forest and  cultivated land respectively. The soil water at 0-5cm depth is from 4.20 to 2.63 cm3/cm3, while at 5-10 cm depth these values vary from 4.32 to 2.13 cm3/cm3 under forest and cultivation land use. The pH (H2O) is 6.9 to 7.16 with low electrical conductivity of 0.13 dS/m(forest) and 0.12 dS/m (cultivation). The CEC of soils is recorded as 8.60 cmol kg-1 (forest) to 8.54 cmol kg-1 (cultivated)whereas  total nitrogen content of 1.21 g kg-1 and 1.11 g kg-1 and available phosphorus of 8.78 mg kg-1 (cultivated) and 5.47 mg kg-1 (forest).. Results indicate that soil fertility parameters were moderate to low for cultivated land and at all slope positions, suggesting that soil fertility management is required in order to make agriculture sustainable on Afaka area.


Author(s):  
Pavlo Kucher ◽  
Ivan Voloshyn ◽  
Andrii Kukhtiy

The article highlights the features of conducting soil excursion cognitive routes. We have proposed a comprehensive cognitive route for tourists of various degrees of educational level: schoolchildren and students of natural sciences. For each type of tourists, according to their wishes, information on natural features, soil cover and other excursion facilities are provided. Complex excursions are offered to attract more tourists. It is proposed to include in excursion routes: monuments and memorable places, architectural, archaeological, historical, sacral, museum and other valuable tourist objects. The excursion route in the Volyn region consists of eight soil study areas, where information is provided on the natural soil conditions, the most common types of soils, including gray forest soils, typical chernozems, sod-podzolic soils, peat soils and peat bogs. Two soils study areas are located on the forest-steppe area, where information on the main types of soils, their granulometric composition, and chemical properties are highlighted. The third-eighth field is laid within Volyn Polissya. Based on the study of the features of soil distribution, a soil-cognitive tourism route within the limits of the Forest-steppe and Volyn Polissya has been developed. The tour consists of information on the natural features of this territory, which testify to the conditions of the soil-forming processes, depending on the characteristics of natural conditions. During the soil study route, the peculiarities of distribution of the main types of soils and soil-forming rocks are highlighted. A table is prepared, in which a brief description of all types of soils found on the route and interesting tourist objects is located. Key words: soil, soil science cognitive field, tourist object, soil science route.


EUGENIA ◽  
2016 ◽  
Vol 22 (1) ◽  
Author(s):  
Yefta Pamandungan ◽  
David S. Runtunuwu ◽  
Rinny Mamarimbing ◽  
Jemmy Najoan

ABSTRACT This research aims to study the increase of the yields of sweet corn and soil fertility by applying integrated fertilizers management system in Jajar Legowo 2:1 planting system. The results of this research show that providing the 25% inorganic fertilizers plus 75% organic fertilizers as treatment has given better result for the yields of sweet corn than providing 100% inorganic fertilizers or 100% organic fertilizers as treatment. Chemical properties of the soil before and after the treatment of fertilizers, it is found out that the contents of C-Organic, N of soil, and K2O of the researched soil are categorized as low to very low. However, it is found out that the available content of P2O5 has increased by 4.29 ppm through the 25% inorganic fertilizers plus 75% organic fertilizers as treatment and has increased by 1.73 ppm through the 100% organic fertilizers as treatment. Keywords: integrated fertilizer management, sweet corn, jajar legowo


1917 ◽  
Vol 8 (3) ◽  
pp. 385-417 ◽  
Author(s):  
E. J. Russell ◽  
A. Appleyard

The biochemical decomposition of plant residues and other organic matter in the soil is of fundamental importance for soil fertility. It causes the breaking down of coarse plant fragments which otherwise might open up the soil too much: it leads to the production of colloidal complexes known as humus which exert many beneficial effects both chemical and physical, and it brings about the formation of nitrates, the most important of the nitrogenous plant nutrients.


Sign in / Sign up

Export Citation Format

Share Document