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Pedology at Four Representative Sites of Southern Highland Zone of Tanzania
Johnson Godlove Mtama,
Balthazar Michael Msanya,
Charles Lee Burras
Issue:
Volume 6, Issue 5, September 2018
Pages:
111-121
Received:
24 July 2018
Accepted:
9 August 2018
Published:
6 September 2018
Abstract: To study the soils of Southern Highland Zone of Tanzania, four representative pedons of some landscapes were characterized. Their names and identifiers are Seatondale, Mbimba, Inyala, and Uyole, respectively TzSea 01, TzMb 02, TzIny 03, and TzUy04. The pedons were formed from the weathering of among other materials, colluvial igneous rocks, alluvium, eluvial soils, laterite, lacustrine sands and silts, andesite, pumice, aeolian deposits, and metamorphic rocks including coarse grained and strongly foliated biotite gneisses. Twenty soil samples were taken for laboratory characterization. In addition to classical horizon by horizon descriptions and laboratory analyses, 12 core samples were taken for soil-water retention characterization. The available water holding capacity was rated as very low to low. Pedon descriptions and particle size analysis showed clay eluviation-illuviation was the predominant pedogenic process in all pedons. Soil pH was rated slightly acidic to slightly alkaline. Available P ranged from 0.71 mg/kg at Mbimba to 10.67 mg/kg at Seatondale. Exchangeable bases were variable across and within the profiles; at Uyole and Inyala they were high, while at Seatondale and Mbimba they were low and medium. Values of exchangeable bases showed decreasing trends with profile depths in all sites. C/N ratios ranged between 6 and 18, total nitrogen was rated very low to low in both A and B horizons. CECsoil ranged between 17.2 and 36.4 cmol (+)/kg. Organic carbon ranged from very low to high. The soils apparently developed from extreme and moderate weathering of parent materials. According to the USDA Soil Taxonomy, the pedons classified as Fine, Illitic, Active, Isothermic Typic Hapludult; Fine, Illitic, Active, Isothermic Andic Paleudalf; Fine, Illitic, Active, Isothermic, Mollic Paleudalf; Pumiceous, Mixed, Superactive, Isothermic, Typic Hapludand for Seatondale, Mbimba, Inyala, and Uyole, respectively. The soil depths were deep and very deep. Moisture stress and low levels of some macro-elements highly limited the productivity of the soils.
Abstract: To study the soils of Southern Highland Zone of Tanzania, four representative pedons of some landscapes were characterized. Their names and identifiers are Seatondale, Mbimba, Inyala, and Uyole, respectively TzSea 01, TzMb 02, TzIny 03, and TzUy04. The pedons were formed from the weathering of among other materials, colluvial igneous rocks, alluviu...
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Genotypic Variation for Root Development, Water Extraction and Yield Components in Groundnut Under Low Phosphorus and Drought Stresses
Hamidou Falalou,
Heynikoye Mariama,
Falke Bacharou Achirou,
Halilou Oumarou,
Vadez Vincent
Issue:
Volume 6, Issue 5, September 2018
Pages:
122-131
Received:
7 August 2018
Accepted:
21 August 2018
Published:
11 September 2018
Abstract: [Context] Unpredictable water deficit (drought) and low soil phosphorus (LP) are major interacting constraints to groundnut growth and grain yield in Sahelian zones of West Africa. Combining breeding efforts for drought tolerance and P efficiency could lead to improve tolerance and grains yield in these zones. [Objectives] This study assessed six groundnut genotypes under lysimetric system to better understand the relative importance of P deficiency, water stress, and their interaction; investigate the water extraction pattern of genotypes under these constraints and identify tolerance related traits to accelerate development of more resilient varieties. [Methods] Thus, in experiment 1 (Exp.1) roots traits were investigated at 50% flowering, pod filling stage (60 days after sowing) and maturity stage (90 days after sowing) under high phosphorus (HP) and LP treatments. In experiment 2 (Exp.2), two water regimes (WW=well water, and WS = water stress) were imposed to HP and LP plants and parameters like total transpired water (TTW), transpiration efficiency (TE), water extraction (Wex), pods and haulm weights were investigated. [Results] Roots traits showed significant decrease due to LP stress, pod and haulm weights correlated significantly to roots length density (RLD) and roots dry matter (RDM). Genotypes 12CS-116 and ICGV 12991 revealed tolerant to LP stress while RLD and RDM revealed LP tolerance related traits in groundnut. Interacting effect of LP and drought stress (LPWS) was higher than separate effect of LP and WS. Under LPWS, Wex, TTW, TE, pod and haulm yields decreased significantly. This study suggests that RLD and RDM contributed to Wex in 12CS-116 and ICG 12991 under LPWS. 55-437 and JL-24 with highest TTW showed drought tolerance strategy while drought avoidance strategy could explain 12CS-116, 12CS-79, ICG 12991 and ICGV 97183 response to WS. Pod weight showed tight correlation (R2 =0.7) to TE only under LPWS suggesting that TE explains a large part of pod yield variation under LPWS conditions. TE revealed WS and LPWS tolerance related trait. The genotypic variation observed on Wex and TTW under LPWS suggests different patterns of water extraction and use among the groundnut genotypes.
Abstract: [Context] Unpredictable water deficit (drought) and low soil phosphorus (LP) are major interacting constraints to groundnut growth and grain yield in Sahelian zones of West Africa. Combining breeding efforts for drought tolerance and P efficiency could lead to improve tolerance and grains yield in these zones. [Objectives] This study assessed six g...
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Grafting shaping the Microbial Community Structure to Suppress Verticillium dahliae in the Rhizosphere of Eggplants
Yuling Yin,
Shaochun Luo,
Yunpeng Li,
Jinsong Zhou,
Yongping Tang,
Yuan Liu
Issue:
Volume 6, Issue 5, September 2018
Pages:
132-140
Received:
7 May 2018
Accepted:
7 August 2018
Published:
15 September 2018
Abstract: This study evaluated that grafting as an effective measure on resistance disease in continuous cropping system has a remarkable impact on improving the microbial community population and structure conditions in the rhizosphere of eggplant, which lead to a highly suppressive on the disease incidence. Verticillium dahliae, microbial community and soil enzyme activities in the rhizosphere of both grafted and self-rooted eggplants investigations were conducted in different eggplant growth stages in pot trials to determine the effects of grafting on the soil microbiological properties. In addition, an assessment of the bio-control effects of antagonistic microbes isolated from rhizosphere of grafted eggplants on the incidence of Verticillium wilt was performed. Grafted eggplants exhibited strong resistance (nearly 90%) with a lower pathological incident index. Amounts of Verticillium dahliae in the rhizosphere of grafted eggplants were lower before the fruiting stage compared to non-grafted self-rooting eggplants. Although each general classification of microbes (bacteria, actinomyces and fungi) was reduced over all growth stages by grafting, the ranges of bacterial and actinomycete reduction in the rhizosphere of grafted eggplants were lower compared to self-rooted eggplants. Experimental evidence indicated that grafting increased the relative ratios of Bacteria to Fungi and Actinomycete to Fungi. In terms of functional microbes, amounts of azotobacteria, ammonifying and nitrifying bacteria were significantly higher in grafted eggplants than self-rooted eggplants, especially after floral initiation. Compared to Control, grafting leaded to a significantly positive impacts on invertase, protein enzyme, urease, peroxidase and catalase activities in the rhizosphere of eggplants. Using antagonistic strains have showed strong suppression of Verticillium dahliae growth to study the prevention and curative effects on Verticillium wilt in pot trials.
Abstract: This study evaluated that grafting as an effective measure on resistance disease in continuous cropping system has a remarkable impact on improving the microbial community population and structure conditions in the rhizosphere of eggplant, which lead to a highly suppressive on the disease incidence. Verticillium dahliae, microbial community and soi...
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Impacts of Wheat Powdery Mildew on Grain Yield & Quality and Its Prevention and Control Methods
Hongyun Gao,
Jishan Niu,
Suoping Li
Issue:
Volume 6, Issue 5, September 2018
Pages:
141-147
Received:
3 August 2018
Accepted:
31 August 2018
Published:
28 September 2018
Abstract: As one of the major foliar diseases, wheat powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) affects photosynthesis of nutrient organs, such as stems and leaves, causing a reduction in production to varying degrees. In recent years, it has been found that powdery mildew can also affect grain quality, including nutritional quality and processing quality. Powdery mildew can cause changes of grain protein content， its components, starch content and ratio of amylose to amylopectin, and it can also cause changes of grain volume weight, flour falling number and viscosity, extensograph and farinograph parameters, etc. The studies have also found that powdery mildew can increase the expression level of molecular chaperones and enzymes relating to protein synthesis, which led to the rise in protein synthesis. And glycolysis-related proteins also show high expression levels in grains from infected wheat, which implies that glycolysis is very active and further results in the depletion of starch content. These results show that the research on the mechanism of quality change caused by disease has also made some progress.This paper includes five parts: the first part introduces the infection characteristics of wheat powdery mildew. The second part elaborates the change of wheat yield caused by powdery mildew and its influence mechanism. In the third part, the effect of powdery mildew on wheat quality and its molecular mechanism are discussed. The fourth part analyzes the four prevention and control ways from cultivating disease-resistant varieties, strictly controlling the use of fungicides, advocating spraying silicate and biological control. Finally, the last part is a prospect where the effect of wheat powdery mildew on quality and its molecular mechanism and the comprehensive pollution-free control system of wheat powdery mildew are discussed. The paper aims to provide the basis for the research of quality physiology and pollution-free control of wheat powdery mildew.
Abstract: As one of the major foliar diseases, wheat powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) affects photosynthesis of nutrient organs, such as stems and leaves, causing a reduction in production to varying degrees. In recent years, it has been found that powdery mildew can also affect grain quality, including nutritional quality and ...
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Status of Soil Properties Under Canopy of Farmers’ Preferred Coffee Shade Tree Species, in Adola Rede District, Guji Zone, Southern Ethiopia
Aschalew Emire,
Zebene Asfaw
Issue:
Volume 6, Issue 5, September 2018
Pages:
148-155
Received:
27 June 2018
Accepted:
10 September 2018
Published:
13 October 2018
Abstract: The study was conducted at Adola Rede District, in Guji Zone, Southern Ethiopia. The aim of the study was to investigate farmers’ preference criteria of soil fertility improving shade tree species and to identify Status of soil properties under canopy of farmers’ preferred shade tree species. To address the objectives of this study, all necessary data were collected through key informant interview, questionnaire survey and soil sampling. A total of 20 key informants and 90 households were participated for household interview. Based on their selection criteria, sampled households have done preference ranking of shade tree species used for soil fertility enhancement. The results of this study showed that, farmers’ main selection criteria were based on decomposition rate of shade treelitter fall, soil moisture status under shade tree canopy, coffee yield increments and growth rate of coffee plants under shade tree canopy. Generally, the preference ranking of key informants and respondent households soil fertility improvingcoffee shade tree species were in the order of: Ficus sur>Cordia africana>Millettia ferruginea>Albizia gummifera> croton macrostachyus>Acacia abyssinica. From the identified soil fertility improving coffee shade treespecies, soil samples were taken from under canopy of Ficus sur with 1st rank and Cordia africana with 2nd rank farmers’ preferences. For soil analysis from under canopy of both coffee shade trees and from outside the tree canopy, a total of 48 soil samples were taken. The results of soil properties under canopy of both shade trees showed that SOC, total N, available P, exchangeable K, CEC and soil pH were significantly (P<0.05) higher than outside the tree canopy. The results of BD outside the tree canopy was significantly (P<0.05) higher than undercanopy of both coffee shade trees. However, soil textures under canopy of both coffee shade trees and outside the tree canopy was not significantly different. Based on the finding of this study, statusof soil fertility under canopy of Ficus sur was significantly (P<0.05) higher than Cordia africana. Thus, the soil laboratory analyzed results of soil physico-chemical properties are in agreement with farmers’ rank of coffee shade tree preferences. Therefore, the findings suggest that if knowledge of local farmers is recorded and effectively used with scientific findings, it can provide valuable information. Moreover, for soil fertility enhancement and increments of coffee production incorporation of the two shade trees incoffee farms of similar agro-ecological conditions is paramount.
Abstract: The study was conducted at Adola Rede District, in Guji Zone, Southern Ethiopia. The aim of the study was to investigate farmers’ preference criteria of soil fertility improving shade tree species and to identify Status of soil properties under canopy of farmers’ preferred shade tree species. To address the objectives of this study, all necessary d...
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Effect of Flower Pollination on Fruit Set and Cropping in Apple
Giannina Vizzotto,
Elena Driussi,
Maila Pontoni,
Raffaele Testolin
Issue:
Volume 6, Issue 5, September 2018
Pages:
156-161
Received:
9 August 2018
Accepted:
23 August 2018
Published:
13 October 2018
Abstract: Apple (Malus x domestica Borkh.), being self-incompatible, requires cross-pollination to set fruit regularly. Apple flowers contain ten ovules and the higher the number of fertilized ovules, the larger the fruit size. In commercial orchards, cross pollination is usually guaranteed by intercropping different cultivars and by introducing beehives in the orchard at flowering time. Despite evidence that pollen donors should be close for successful pollen transportation, apple growers often plant large monovarietal blocks with negative consequences on crop load and fruit size. The contribution of wind and bees to apple pollination was studied and compared with hand-pollination in two apple cultivars, ‘Royal Gala’ and ‘Golden Delicious’. Self-pollination was also included as control. Each treatments was replicated in 120 cymes randomly assigned to plants in the central part of large monovarietal blocks (1.61 and 2.72 ha respectively). Fruit set and fruit weight increased moving from wind-pollination to wind + bee-pollination to hand-pollination as a consequence of the increase in the number of seeds per fruit. Fertilization of a single ovule was enough to set fruit after flowering, but the more seed, the larger the fruit. The increase in fruit weight per additional seed was 2.0 g for ‘Royal Gala’ and 4.6 g for ‘Golden Delicious’. This relationship between seed count and fruit weight resulted in fruit set by wind-pollination being mainly in the lower size classes, while wind + bee-pollination and, largely, hand-pollination shifted the fruit size distribution towards larger size classes. This resulted, in turn, in a dramatic increase in grower income. No significant difference between treatments in fruit quality, as assessed by fruit firmness, soluble solids content, titratable acidity, dry matter and starch content, was observed after fruit storage. It is concluded that limiting pollination in the hope of reducing the labor of thinning is not a good strategy, because flowers set fruit with a minimal cross-pollination, even if only a single seed is produced; conversely, the low seed content of fruit due to insufficient pollination is responsible for great losses for grower in both total crop yield and income.
Abstract: Apple (Malus x domestica Borkh.), being self-incompatible, requires cross-pollination to set fruit regularly. Apple flowers contain ten ovules and the higher the number of fertilized ovules, the larger the fruit size. In commercial orchards, cross pollination is usually guaranteed by intercropping different cultivars and by introducing beehives in ...
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