Stem Collar Diameter Research Articles

Integrated Management of Root-Knot Nematode (Meloidogyne Spp.) Using Fresh Organic Manure and Crotalaria brevidens Intercrop for Improved Growth and Yield of Tomato

Tomato (Solanum lycopersicum L.) is one of the most important vegetables worldwide. Tomato productivity is limited by, among other factors, biotic constraints including root-knot nematodes (Meloidogyne species) which lower both quality and quantity of the crop. Two trials were conducted at the Horticulture Research and Teaching Field, Egerton University, Kenya, to evaluate effects of fresh organic manure and slender leaf (Crotalaria brevidens var. brevidens Benth.) intercrop on management of root-knot nematode during tomato production as well as establish their effect on tomato growth and yield. Variables measured were nematode infestation, plant height, stem collar diameter, number of internodes and branches, number of fruits, and fresh fruit weight. Use of fresh organic manure and slender leaf intercrop suppressed the nematode population by 27.8% to 53.5% reduction and significantly increased tomato fruit numbers by 22.2% to 49.7% and fresh fruit weight by 24.5% to 80.4% when used alone or in combinations compared to the control treatment. The combination of fresh goat dung and slender leaf intercrop resulted in the highest reduction in nematode population of 53.5% and highest increase in total number of fruits of 49.7% and fresh fruit weight of 80.4%.

Seedling quality of Agonandra brasiliensis in response to different Osmocote® doses and recipient volumes

The objective of this work was to evaluate seedlings quality of the tree species Agonandra brasiliensis under different doses of the controlled release fertilizer (CRF) Osmocote® and recipient volumes. The experiment was set up in a factorial design for two recipient volumes (1.8 L and 2.2 L) and five CRF doses (0.0; 0.5; 1.0; 2.0; and 3.0 g L-1 of substrate). Four repetitions of one plant each were used. After transplanting seedlings, stem height, stem collar diameter, and the robustness index (RI) were measured in a monthly basis during eight months. The highest seedlings growth was observed with the CRF Osmocote® dose of 2.0 g L-1 and recipients of 2.2 L. The treatment with CRF dose of 2.0 g L-1 in 240 days presented higher initial accumulated growth in height of A. brasiliensis seedlings (mean = 31.38 cm). Seedlings under the dose of 2.0 g L-1 presented 85.90% increase of stem height in relation to the control (substrate without CRF). CRF Osmocote® had positive effect on growth of A. brasiliensis seedlings. Growth was influenced by the different CRF doses and recipient volumes, both for the variables stem height and stem collar diameter and for the RI. The dose 2.0 g L-1 allowed greater accumulated growth in height and diameter in 240 days.

Effectiveness of Fortified Liquid Organic Manure and Inorganic Fertilizer on the Growth, Physiological and Pesticidal Response of African Nightshade (Solanum scabrum)

Aims: To assess the effectiveness of fortified liquid organic manure, zero fertilizer applications and urea on the growth, physiological and pesticidal response of Solanum scabrum.
 Study Design: Complete randomized block experimental design.
 Place and Duration of Study: The green house facility and agricultural research farm at the Pan African Institute for Development – West Africa (PAID-WA), Buea, Cameroon, from August to November 2017.
 Methodology: Four experimental units with 4 treatments including: two fortified liquid organic manure (T1 and T2,) control (T3) and urea (T4), were established using 96 planting pots. The quantity and application rates for the liquid manure and urea were 4000 L/ha, once and twice a week, and 200 kg/ha, respectively. Leaf colour, leaf size, number of leaves per plant, plant height, stem collar diameter and growth rate were measured. Two plots with three soil beds each, was also established to record pesticide treatment response by counting the number of leaves eaten by insects
 Results: T2 had darker green leaves, tallest plants (27.57±11.87 cm), highest number of leaves (27.65±25.46 units), largest leaf size (38.56±21.96 cm2), biggest stem collar diameter (1.54±0.41 cm) and highest growth rates (2.54±1.02, 5.18±3.40, and 0.11±0.03 cm/week for height, number of leaves and stem collar diameter, respectively). T2 effects differed significantly (P = 0.00) from T3 and T4. T2 and T1 also reduced pest attacks on leaves significantly (P = 0.00) compare to T3.
 Conclusion: Liquid extracts concoctions of biomass and pesticidal botanicals prove useful towards the development of effective bio-repellent organic fertilizers. These can contribute to reducing the use of synthetic agro-chemicals, hence decreasing residual environmental and human health hazards.

Effects of Nitrogen and Phosphorus Fertilizer Rates on Maize (Zea mays L.) Growth and Yields in Terraced Lands of Medium and High Altitude Regions of Rwanda

Depletion of nitrogen and phosphorus in terraced hilly areas of Rwanda has lowered maize (Zea mays L.) production. Trials were carried out in 2017 and 2018 in four-year-old-terraced Lixisols and Acrisols of medium and high altitudes to determine effect of nitrogen and phosphorus fertilizer application rates on maize yields. A factorial arrangement of four levels of nitrogen (0, 60, 120 and 180 kg N ha-1) and phosphorus (0, 40, 80 and 120 kg P2O5 ha-1) in a randomized complete block design with 3 replications, was used. Results showed that combinations of 120 - 180 kg N ha-1 and 80 - 120 kg P2O5 ha-1 resulted in significantly (P less than 0.05) higher increases in plant height (45 – 60 % and 56 – 70 % over the control), stem collar diameter (63 – 74 % and 43 % over the control) and grain yields (3 times over the control; i.e. 6.40 – 6.46 t ha-1 and 6.02 - 6.12 t ha-1) in medium and high altitude sites. The optimum fertilizer rates are 176.6 kg N ha-1 and 96.2 kg P2O5 ha-1 in terraced Lixisols of medium altitude area. Land use needs to adjust fertilizer application to these optimum rates for enhanced maize yields in this area and other regions with similar agro-ecological characteristics. Further studies on integrated effects of N and P fertilizers are recommended.

Growth Performance and Adaptive Strategy of Early Seedlings of Three Savanna Woody Species in Pots as Feedback to the Soil of Macrotermes Subhyalinus Mound

Heterogeneous physiognomy and observed diversity of woody vegetation in savanna are considered as specific responses of seedling species during their growth to the given site characteristics changeable with time. Consequently, understanding early plant attitude using different growth soil is an important indicator in choosing species to introduce or to assist natural or artificial regeneration to the extent that establishment and productivity of plant species are not solely controlled by the effects of habitat modification and/or environmental resource availability but mostly by seedling quality. This study focused on comparative assessment of growth performance and adaptive traits of early seedlings of Balanites aegyptiaca, Diospyros mespiliformis and Tamarindus indica three multipurpose species between of Macrotermes subhyalinus mound and surrounding area in order to understand the attitudes of woody species hosted by termite mounds. Seedlings of similar age per species were grown in plastic bags as pots containing composite soils sampled till a depth of 30 cm on mounds and surrounding area in Tiogo state forest and of which the amount of retained water, carbon (C), nitrogen (N), calcium (Ca), magnesium (Mg), assimilable phosphorus (ass. P) and potassium (K) were quantified prior to growth experiment. Height and collar diameter of seedling stems, final length and diameter of the main root were measured; the total dry biomass of root and shoot and, root to shoot ratio were evaluated for seedlings up to 5 months relating to the soil origin. Mean values of retained water and selected nutrients were higher for mound soil than for surrounding soil. Besides, the studied parameters of T. indica seedlings were significantly higher for mound soil than those recorded for surrounding soil (P<0.05) whereas seedlings of B. aegyptiaca and D. mespiliformis exhibited an increase final stem collar diameter and main root length on mound soil (P=0.039 and 0.028 respectively). Root to shoot ratio of B. aegyptiaca seedlings was positively correlated with great N content and that of D. mespiliformis seedlings with great concentration of Ca. Growth performance and adaptive traits of early seedlings of B. aegyptiaca, D. mespiliformis and T. indica were remarkable on M. subhyalinus mound soil compared to surrounding soil relating to the great level ofsoil fertility. Therefore, understanding the attitude of woody seedlings of local or exotic species is an important key in global plantation programs or assisting natural regeneration for biodiversity management and conservation.

Improving French Bean (PhaseolusVulgaris L.) Pod Yield and Quality Through the Use of Different Coloured Agronet Covers

French bean (Phaseolus vulgaris L.) is among important vegetables in supplying proteins, vitamins, minerals and dietary fiber to humans worldwide. Its successful production in the tropics is, however, constrained by abiotic and biotic stresses as the crop is predominantly grown in open fields. Netting technology has been proved successful in protecting crops against adverse weather and insect pests. Coloured net technology is an emerging technology, which introduces additional benefits on top of the various protective functions of nettings. Two trials were conducted at the Horticulture Research and Teaching Field, Egerton University, Kenya to evaluate the effects of different coloured agronet covers on growth, pod yield and quality of French bean. A randomized complete block design (RCBD) with six treatments and four replications was used. French bean plants were grown under a white, blue, yellow, tricolour or grey net cover with open field production as the control. Variables measured included days to emergence and emergence percentage (%), stem collar diameter, plant height, number of branches and internodes, internode length and crop yield. French bean grown under the different coloured net covers showed relatively better growth and crop performance marked by more pods and higher total yields and percentage of marketable yields compared to those grown in the open field. Growing French bean under net covers hastened the rate of pod maturation more-so under the light-coloured colour-nets. Findings of this study demonstrate the potential of coloured net covers in improving French bean pod yield and quality under tropical field conditions.

Effects of defoliation on current-year stem growth and fine root dynamics in Fraxinus mandschurica and Larix gmelinii seedlings

Aims Defoliation by insects leads to significant changes in tree growth and physiological metabolism. However, how fine root dynamics would respond to defoliation is still poorly understood. The objectives of this study were to: 1) compare the responses of height and stem collar diameter to defoliation in manchurian ash (Fraxinus mandschurica) and Dahurian larch (Larix gmelinii) seedlings; 2) quantify the effects of defoliation on the seasonal dynamics of fine root production and mortality in the two species. Methods Manchurian ash and Dahurian larch seedlings, with different biomass allocation and height growth strategy, were used to investigate the effects of different levels of artificial defoliation (0% (control), 40% and 80% leaf area removal) on the growth of aboveground (height and stem collar diameter) and belowground (production and mortality of fine roots (diameter ≤ 2 mm)). Minirhizotron approach was employed to determine the seasonal dynamics of fine roots, and seedling height and stem collar diameter were measured concurrently. Important findings The results showed that: 1) defoliation reduced the growth of seedling height (but statistically not significant) and stem collar diameter in both species, with a stronger effect on the stem collar diameter. Effects on aboveground growth by defoliation were enhanced by increasing defoliation intensity in both species. Compared with the control seedlings, the height and collar diameter of ash were reduced by 3.3% to 12.1% and 5.7% to 23.1%, respectively, while the height and collar diameter of larch were only slightly reduced (< 12%). 2) Defoliation significantly reduced live fine roots in both species (p < 0.001), with the reduction in relative growth rate of fine roots being enhanced with defoliation intensity. 3) Defoliation significantly reduced fine root production in both species (p < 0.05), had not apparent effect on fine root mortality. We conclude that defoliation imposes significant effects on aboveground growth (especially stem collar diameter) in ash and belowground growth 李俊楠等: 去叶对水曲柳和落叶松苗木当年生长及细根动态的影响 1083 doi: 10.3724/SP.J.1258.2014.00102 (particularly root production) in larch. Our findings provide some insights into the inter-specific difference in the response of fine root dynamics to canopy carbon supply.

Seed Germination and Effects of Three Watering Regimes on the Growth of &amp;lt;i&amp;gt;Dialium guineense&amp;lt;/i&amp;gt; (Wild) Seedlings

The effectiveness of three pre-germination treatments in breaking dormancy of the seeds of Dialum guineense and effects of three watering regimes on the growth performance of the seedlings were investigated. The pre-germination treatments were: soaking in hot water for 10 seconds and cooling down in cold water (T1), soaking in cold water for 24 hours (T2), soaking in running water for 48 hours (T3) and control (T4), while watering regimes include: watering once daily in the morning (W1), watering once every two days in the morning (W2) and watering once every three days in the morning (W3). The results showed that germination occurred first at 5 days after sowing (5 DAS) among the seeds soaked in cold water for 24 hours before sowing (T2), while the untreated seeds (control) took the longest period of 12 days before germination occurred. T1 had the highest germination value of 49.6% while T3 had the least of 31.2%. The effects of watering regimes were found to be significantly different on stem-collar diameter, leaf area and total dry weight (P 2 and W3 supported the best growth performance. It is concluded from the results that T2 should be adopted for breaking the dormancy of Dialium guineense seeds and watering interval of three days would not dispose the seedlings to water-stress.

Comparative Study of Pre-Germination Treatments and their Effects on the Growth of Tectona Grandis (Linn. F) Seedlings

A comparative study was conducted for three months to investigate the effect of pre-germination treatment on morphological and physiologicalcharacteristics of Tectona grandis (Linn. F) seedlings. Matured seeds of Tectona grandis were collected from mother trees in Uyo and exposed to four pre-germination treatments – soaking in running water (SRW) for 24 hours, soaking in stagnant water (SSW) for 24 hours, soaking in boiled water (SBW) for 5 minutes and no treatment as control. Treated seeds were sown in the of Forestry and Wildlife Department nursery, University of Uyo by broadcast method in germination boxes. At two-leaf stage, fairly uniformed seedlings from each treatment were selected and transplanted into polypots filled with topsoil and laid on the field in completely randomized design, replicated three times. Morphological and physiological features were assessed after two weeks of transplanting and fortnightly thereafter. Data were subjected to ANOVA and the significant means separated using F-LSD. The result showed that pre-germination treatment had significant effect (p>0.05) on seedling height, number of leaves, stem collar diameter and biomass production while there was no significant effect (p

Performance di recenti imboschimenti con quercia da sughero in ex-coltivi

Recently, significant forestry activities have taken place in Sardinia thanks to EU Regulation 2080/92 funds. Some 80% of the afforestated surface has been planted with holm oak and cork oak. The latter also characterizes 89% of the reforestation area. Given the funding source, plantations have been established on farmlands. Growth performances of these recent cork oak stands have been quantitatively evaluated and compared with the performances of two experimental plots. In Gallura (north-east of Sardinia), that is the traditional cork production area and still is economically the most important cork district of the island, these new cork oak plantations have an average size of 28 ha. They have been established on lands that, before plantation, were either pastures (30%) or arable lands (70%). Plantation failures are limited to 8.8% of the total (in term of mass) and seem independent of environmental factors or plantations species composition (conifers have been frequently used as secondary species). Average growth of the stem, measured above cork at collar height, is in the range 4 to 8mm/year with a mean value of 5.5mm/year. No correlation appears with either environmental conditions or species composition of the plantations. In the first experimental plot, soil management practices (natural vegetation removal vs. its cutting and mulching) does not differentiate young plants growth trends. In the control subplots (no removal) stem collar diameter is 20% smaller. Localized manual hoeing around trunk base increased the diameters by 13% but reduced cork thickness by 21%. The second experimental plot allows comparisons among 27 Mediterranean proveniences of cork oak. The trial exhibits reduced genetic influence: diameters and heights growth are significantly different only among extreme groups. In conclusion, reduced growth performances of the plantations established in farmlands is due, to some extent, to the limitations inherent with private land management (constrained to costs minimization) and, on the other hand, to the generally very limited thickness of Gallura soils. Demand for good quality commercial cork is steadily raising. To sustain the request, in the short term, it would be necessary to extend financial support for plantations care, from 5 to 10 years, or even up to the first stripping (virgin cork).

Genetic variation in seed and seedling traits in 12 African provenances of Faidherbia albida (del.) A. Chev. at Lodwar, Kenya

The extent of genetic variation in seed length, width, thickness, weight and germination percentage and seedling traits among and within 12 African provenances of Faidherbia albida was examined. The regional provenances showed a consistent variation in seed length, seed width and seed weight: the southern African provenances had the largest seeds and west African provenances the smallest. Seedling height, stem collar diameter and true leaf number differed (P = 0.05) among the provenances 90 days after germination. The seedlings from west Africa were shorter, had smaller stem collar diameter and fewer leaves. In contrast, the southern and east African provenances had taller seedlings with bigger seedling diameter and more leaves per seedling. Seedling traits did not show clear-cut divisions between southern and east African provenances, but the west African provenances formed a distinct group. Positive correlations were found in some of the seed characteristics and seedling height among provenances, which could be an important criterion for early provenance selection. Greater variation was observed for seed and seedling traits among than within provenances suggesting that selection among provenances might result in rapid genetic gain for the traits studied.