Fatty Alcohol Application to Control Meristematic Regrowth in Bottle Gourd and Interspecific Hybrid Squash Rootstocks Used for Grafting Watermelon

Application of fatty alcohol compounds to rootstock meristems can control rootstock meristematic regrowth, thus decreasing the cost of producing grafted watermelon transplants by reducing the labor. Eight rates of Fair 85® and Off-Shoot T®, two commercially available fatty alcohol compounds, were applied to the meristem region of bottle gourd (Lagenaria sicereria cv. Emphasis) and interspecific hybrid squash (Cucurbita maxima × Cucurbita moschata cv. Carnivor) rootstocks to determine the optimal application rate to control regrowth without damaging the remaining plant parts. A water-only control treatment was also included. Rootstock seedlings were rated for damage and regrowth on Days 1, 7, 14, and 21 after treatment. Damage increased and regrowth decreased with increasing rates of fatty alcohol compound. In addition, a significant compound-by-rate interaction indicated that inert ingredients in the fatty alcohol formulation have an effect on both damage and regrowth. The optimal treatment rate, e.g., providing at least 95% control of regrowth with less than 10% damage, was found to be between a 5% (Off-Shoot T®) and 6.25% (Fair 85®) fatty alcohol application. At the optimal treatment rate, no adverse effects to grafting success were observed in the grafting procedure.

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Effects of two wood-based biochars on the fate of added fertilizer nitrogen—a 15N tracing study

Biology and Fertility of Soils ◽

10.1007/s00374-020-01534-0 ◽

2021 ◽

Author(s):

Subin Kalu ◽

Gboyega Nathaniel Oyekoya ◽

Per Ambus ◽

Priit Tammeorg ◽

Asko Simojoki ◽

...

Keyword(s):

Plant Uptake ◽

Plant Biomass ◽

Application Rate ◽

Control Treatment ◽

Organic N ◽

N Leaching ◽

Soil N ◽

Mineral N ◽

Total N ◽

Application Rates

AbstractA 15N tracing pot experiment was conducted using two types of wood-based biochars: a regular biochar and a Kon-Tiki-produced nutrient-enriched biochar, at two application rates (1% and 5% (w/w)), in addition to a fertilizer only and a control treatment. Ryegrass was sown in pots, all of which except controls received 15N-labelled fertilizer as either 15NH4NO3 or NH415NO3. We quantified the effect of biochar application on soil N2O emissions, as well as the fate of fertilizer-derived ammonium (NH4+) and nitrate (NO3−) in terms of their leaching from the soil, uptake into plant biomass, and recovery in the soil. We found that application of biochars reduced soil mineral N leaching and N2O emissions. Similarly, the higher biochar application rate of 5% significantly increased aboveground ryegrass biomass yield. However, no differences in N2O emissions and ryegrass biomass yields were observed between regular and nutrient-enriched biochar treatments, although mineral N leaching tended to be lower in the nutrient-enriched biochar treatment than in the regular biochar treatment. The 15N analysis revealed that biochar application increased the plant uptake of added nitrate, but reduced the plant uptake of added ammonium compared to the fertilizer only treatment. Thus, the uptake of total N derived from added NH4NO3 fertilizer was not affected by the biochar addition, and cannot explain the increase in plant biomass in biochar treatments. Instead, the increased plant biomass at the higher biochar application rate was attributed to the enhanced uptake of N derived from soil. This suggests that the interactions between biochar and native soil organic N may be important determinants of the availability of soil N to plant growth.

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Exploring Suitable Biochar Application Rates with Compost to Improve Upland Field Environment

Agronomy ◽

10.3390/agronomy11061136 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1136

Author(s):

Se-Won Kang ◽

Jin-Ju Yun ◽

Jae-Hyuk Park ◽

Ju-Sik Cho

Keyword(s):

Soil Quality ◽

Chinese Cabbage ◽

Early Period ◽

Crop Productivity ◽

Application Rate ◽

Control Treatment ◽

N2o Emissions ◽

Treatment Area ◽

Application Rates ◽

Upland Field

A field experiment was carried out to investigate crop productivity, emissions of carbon dioxide (CO2) and nitrous oxide (N2O), and soil quality of an upland field treated with compost and varying rates of biochar (BC) derived from soybean stalks during crop growing periods in a corn and Chinese cabbage rotation system. Compost was supplemented with BC derived from soybean stalks at varying rates of 5, 10, 15, and 20 t ha−1 (BC5, BC10, BC15, and BC20, respectively); the control (BC0) area was untreated. Our results reveal that crop productivity and emissions of CO2 and N2O varied significantly with the biochar application rate. Moreover, irrespective of the biochar application rate, crop productivity was improved after BC application as compared to the control treatment area, by 11.2–29.3% (average 17.0 ± 8.3%) for corn cultivation and 10.3–39.7% (average 27.8 ± 12.7%) for Chinese cabbage cultivation. Peak emissions of CO2 and N2O were mainly observed in the early period of crop cultivation, whereas low CO2 and N2O emissions were determined during the fallow period. Compared to the control area, significant differences were obtained for CO2 emissions produced by the different biochar application rates for both crops. During the two cropping periods, the overall N2O emission was significantly decreased with BC5, BC10, BC15, and BC20 applications as compared to the control, ranging from 11.1 to 13.6%, 8.7 to 15.4%, 23.1 to 26.0%, and 15.0 to 19.6%, respectively (average 16.9% decrease in the corn crop period and 16.3% in the Chinese cabbage crop period). Soil quality results after the final crop harvest show that bulk density, soil organic carbon (SOC), pH, and cation exchange capacity (CEC) were significantly improved by biochar application, as compared to the control. Taken together, our results indicate that compost application supplemented with biochar is potentially an appropriate strategy for achieving high crop productivity and improving soil quality in upland field conditions. In conclusion, appropriate application of biochar with compost has the concomitant advantages of enriching soil quality for long-term sustainable agriculture and reducing the use of inorganic fertilizers.

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Physiological and Productivity Responses of High-wire Tomato as Affected by Supplemental Light Source and Distribution within the Canopy

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.141.2.196 ◽

2016 ◽

Vol 141 (2) ◽

pp. 196-208 ◽

Cited By ~ 13

Author(s):

Celina Gómez ◽

Cary A. Mitchell

Keyword(s):

Photosynthetic Activity ◽

Experimental Period ◽

Fruit Yield ◽

Tissue Temperature ◽

Control Treatment ◽

Fresh Weight ◽

Tomato Production ◽

Light Emitting ◽

Plant Parts ◽

Use Efficiency

The relative coolness-to-touch of light-emitting diodes (LEDs) has enabled commercial implementation of intracanopy lighting (ICL) in the greenhouse. Intracanopy lighting, which refers to the strategy of lighting along the side or from within the foliar canopy, can increase canopy photosynthetic activity, but physiological and productivity responses of high-wire greenhouse tomato (Solanum lycopersicum) to intracanopy supplemental lighting (SL) still are not yet fully understood. Two consecutive production experiments were conducted across seasons in a glass-glazed greenhouse located in a midnorthern, continental climate [lat. 40°N (West Lafayette, IN)]. Plants were grown from winter-to-summer [increasing solar daily light integral (DLI)] and from summer-to-winter (decreasing solar DLI) to compare three SL strategies for high-wire tomato production across changing solar DLIs: top lighting with high-pressure sodium lamps (HPS) vs. intracanopy LED vertical towers vs. hybrid SL (HPS + horizontal ICL-LEDs). A control treatment also was included for which no SL was provided. Supplemental DLI for each experimental period was adjusted monthly, to complement seasonal changes in sunlight, aiming to approach a target total DLI of 25 mol·m‒2·d‒1 during fruit set. Harvest parameters (total fruit fresh weight, number of fruit harvested, and average cluster fresh weight), tissue temperature, chlorophyll fluorescence, and stomatal conductance (gS) were unaffected by SL treatment in both experiments. Among the physiological parameters evaluated, CO2 assimilation measured under light-saturating conditions, light-limited quantum-use efficiency, and maximum gross CO2 assimilation (Amax) proved to be good indicators of how ICL reduces the top-to-bottom decline in leaf photosynthetic activity otherwise measured with top lighting only (HPS-SL or solar). Although SL generally increased fruit yield relative to control, lack of SL treatment differences among harvest parameters indicates that higher crop photosynthetic activity did not increase fruit yield. Compared with control, intracanopy SL increased yield to the same extent as top SL, but the remaining photoassimilate from ICL most likely was partitioned to maintain nonharvested, vegetative plant parts as well.

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Foliar Zn Spraying Simultaneously Improved Concentrations and Bioavailability of Zn and Fe in Maize Grains Irrespective of Foliar Sucrose Supply

Agronomy ◽

10.3390/agronomy9070386 ◽

2019 ◽

Vol 9 (7) ◽

pp. 386 ◽

Cited By ~ 1

Author(s):

Haiyong Xia ◽

Weilin Kong ◽

Lan Wang ◽

Yanhui Xue ◽

Wenlong Liu ◽

...

Keyword(s):

Agronomic Traits ◽

Application Rate ◽

Deionized Water ◽

Control Treatment ◽

Agricultural Practice ◽

N Application ◽

Application Rates ◽

N Application Rate ◽

Maize Grain ◽

Sucrose Supply

Zinc (Zn) deficiency is a global nutritional problem that is reduced through agronomic biofortification. In the current study, the effects of foliar spraying of exogenous ZnSO4·7H2O (0.2% in Quzhou and 0.3% in Licheng, w/v) and/or sucrose (10.0%, w/v) on maize (Zea mays L.) agronomic traits; concentrations of Zn, iron (Fe), calcium (Ca), total phosphorus (P), phytic acid (PA) P, carbon (C), and nitrogen (N); C/N ratios; and Zn and Fe bioavailability (as evaluated by molar ratios of PA/Zn, PA × Ca/Zn, PA/Fe and PA × Ca/Fe) in maize grains were studied under field conditions for two years at two experimental locations. The results confirmed that there were no significant differences in maize agronomic traits following the various foliar treatments. Compared with the control treatment of foliar spraying with deionized water, foliar applications of Zn alone or combined with sucrose significantly increased maize grain Zn concentrations by 29.2–58.3% in Quzhou (from 18.4–19.9 to 25.2–29.6 mg/kg) and by 39.8–47.8% in Licheng (from 24.9 to 34.8–36.8 mg/kg), as well as its bioavailability. No significant differences were found between the foliar spraying of deionized water and sucrose, and between Zn-only and “sucrose + Zn” at each N application rate and across different N application rates and experimental sites. Similar results were observed for maize grain Fe concentrations and bioavailability, but the Fe concentration increased to a smaller extent than Zn. Foliar Zn spraying alone or with sucrose increased maize grain Fe concentrations by 4.7–28.4% in Quzhou (from 13.4–17.1 to 15.2–18.5 mg/kg) and by 15.4–25.0% in Licheng (from 24.0 to 27.7–30.0 mg/kg). Iron concentrations were significantly and positively correlated with Zn at each N application rate and across different N application rates and experimental locations, indicating that foliar Zn spraying facilitated the transport of endogenous Fe to maize grains. Therefore, foliar Zn spraying increased the Zn concentration and bioavailability in maize grains irrespective of foliar sucrose supply while also improving Fe concentrations and bioavailability to some extent. This is a promising agricultural practice for simultaneous Zn and Fe biofortification in maize grains, i.e., “killing two birds with one stone”.

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Estimating the impact of antiretroviral therapy on HIV-TB co-infection: Optimal strategy prediction

International Journal of Biomathematics ◽

10.1142/s1793524521500042 ◽

2020 ◽

pp. 2150004

Author(s):

Tanvi ◽

Rajiv Aggarwal

Keyword(s):

Optimal Control ◽

Equilibrium Point ◽

Treatment Strategies ◽

Hiv Treatment ◽

Time Dependent ◽

Control Parameters ◽

Treatment Rate ◽

Tb Treatment ◽

The Cost ◽

The Impact

In this paper, a nonlinear population model for HIV-TB co-infection has been proposed. The model is incorporated with the effect of early and late initiation of HIV treatment in co-infectives already on TB treatment, on the occurrence of Immune Reconstitution Inflammatory syndrome (IRIS). A 15-dimensional (15D) mathematical model has been developed in this study. We begin with considering constant treatment rates and thereafter, proceed to time-dependent treatment rates for co-infectives as control parameters. The basic reproduction number, a threshold quantity, corresponding to each HIV and TB sub-model has been computed in case of constant controls. With constant values of control parameters, mathematical analysis shows the existence and local stability of the disease-free equilibrium point and the endemic equilibrium point for the model. Together with time-dependent parameters, an optimal control problem is introduced and solved using Pontryagin’s maximum principle with an objective to minimize the number of infectives and disease induced deaths along with the cost of treatment. Numerical simulations are performed to examine the effect of reproduction numbers on control profiles and to identify, the ideal combination of treatment strategies which provides minimum burden on a society. Numerical results imply that if both HIV and TB are endemic in the population, then in order to bring in minimum burden from the co-infection, optimal control efforts must be enforced rather than constant treatment rate.

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Larvicidal and pupicidal action of medicinal plant extracts against dengue mosquito Aedes albopictus (Skuse) (Diptera: Culicidae)

Indian Journal of Animal Research ◽

10.18805/ijar.9592 ◽

2015 ◽

Author(s):

Shabab Nasir ◽

Iram Nasir ◽

Muhammad Asrar ◽

Mustapha Debboun

Keyword(s):

Medicinal Plants ◽

Aedes Albopictus ◽

Probit Analysis ◽

Control Treatment ◽

Immature Stages ◽

Life Stages ◽

Plant Parts ◽

Soxhlet Apparatus ◽

Medicinal Plant Extracts ◽

Treatment Data

The efficacy of essential oils from some medicinal plants as a larvicidal and pupicidal agent was tested against Aedes albopictus. The oils were extracted from different plant parts (leaves, branches and rhizomes) with Soxhlet apparatus using acetone as a solvent. The mortality was determined after 8, 16, 24 and 48 hours with different concentrations (100, 200, 300 and 400 ppm) along with a control treatment. Data was analysed by Probit analysis to calculate LC50 and LT50. Results revealed that early immature stages were more susceptible than later ones. Ginger was more effective with the lowest LC50 values after 8 and 16 hours against all tested life stages followed by peppermint, basil, eucalyptus and neem. In addition, basil was efficacious after 24 and 48 hours. Therefore, we conclude that these oils can be used in combination for the management of mosquito immature stages.

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Effects of Azoxystrobin Application Rate and Treatment Interval on the Control of Rhabdocline pseudotsugae on Douglas-fir Christmas Trees

Plant Health Progress ◽

10.1094/php-2005-0617-01-rs ◽

2005 ◽

Vol 6 (1) ◽

pp. 8

Author(s):

Ricky M. Bates ◽

David A. Despot

Keyword(s):

Control Program ◽

Application Rate ◽

Douglas Fir ◽

Disease Index ◽

Christmas Tree ◽

Infection Rates ◽

Infection Period ◽

Christmas Trees ◽

The Cost ◽

Tree Production

Rhabdocline needlecast caused by Rhabdocline pseudotsugae is the primary disease limiting Douglas-fir Christmas tree production in the northeastern United States. Azoxystrobin (Quadris) was recently registered for control of needlecasts on conifers, but little is known about its efficacy. In 2002, azoxystrobin was applied to field-grown Lincoln N.F. Douglas-fir Christmas trees at 0.14 or 0.28 g a.i./liter as the first or second spray of a chlorothalonil-based control program. In 2003, four sequential sprays of azoxystrobin at 0.28, 0.55, and 1.10 g a.i./liter were compared to chlorothalonil treatments. Untreated trees at both Pennsylvania test sites in both years were heavily infected, confirming high inoculum levels and environmental conditions favorable for infection. The standard program that consisted of 1.29 g a.i./liter chlorothalonil applications was very effective in controlling Rhabdocline in all experiments. In 2002, application interval had a significant effect on efficacy. Trees sprayed with 0.14 and 0.28 g a.i./liter azoxystrobin 9 days prior to an infection period had a higher disease index rating than those sprayed 2 days prior to the same infection period. Application rate did not appear to have an effect on efficacy. Trees receiving 1.10 g a.i./liter azoxystrobin had the same disease index rating as trees receiving the 0.28 g a.i./liter rate. In all cases, azoxystrobin treatments had significantly higher infection rates than the standard chlorothalonil treatment. The level of natural inoculum present at each site also appeared to play a role in azoxystrobin efficacy. Azoxystrobin is more than twice the cost of chlorothalonil and the data presented does not support any cost incentive for its inclusion in a Rhabdocline control program. Accepted for publication 19 May 2005. Published 17 June 2005.

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Control of Fusarium Wilt of Watermelon by Grafting onto Bottlegourd or Interspecific Hybrid Squash Despite Colonization of Rootstocks by Fusarium

Plant Disease ◽

10.1094/pdis-01-13-0100-re ◽

2014 ◽

Vol 98 (2) ◽

pp. 255-266 ◽

Cited By ~ 21

Author(s):

A. P. Keinath ◽

R. L. Hassell

Keyword(s):

Fusarium Wilt ◽

Interspecific Hybrid ◽

Citrullus Lanatus ◽

Disease Incidence ◽

Field Performance ◽

Control Treatment ◽

Infested Field ◽

Race 1 ◽

Seedless Watermelon ◽

Race 2

Grafting watermelon (Citrullus lanatus var. lanatus) onto rootstocks of interspecific hybrid squash (Cucurbita moschata × C. maxima), bottle gourd (Lagenaria siceraria), or citron (Citrullus lanatus var. citroides) has been used in Asia and Israel to mange Fusarium wilt of watermelon caused by Fusarium oxysporum f. sp. niveum. The objectives of this study were to determine the frequency of infection of six rootstocks by F. oxysporum f. sp. niveum races 1 and 2 and the field performance of grafted rootstocks in Charleston, SC. Grafted and nongrafted watermelon and rootstock plants were inoculated in the greenhouse with race 1, race 2, or water (the control treatment). With both races, the frequency of recovery of F. oxysporum from scion and rootstock portions of inoculated watermelon plants grafted onto ‘Ojakkyo’ citron was greater than from watermelon plants grafted onto ‘Shintosa Camel’ and ‘Strong Tosa’ interspecific hybrid squash, and from plants grafted onto ‘Emphasis’, ‘Macis’, and ‘WMXP 3945’ bottlegourd. For nongrafted plants inoculated with race 1, percent recovery also was greater from Ojakkyo than from interspecific hybrid squash and bottlegourd. For nongrafted plants inoculated with race 2, F. oxysporum was recovered from the base of ≥79% of all inoculated plants. More than two-thirds (15) of 21 isolates recovered from the tops or scions of inoculated plants were pathogenic on watermelon. In spring 2010 and 2011, the six rootstocks were grafted with seedless watermelon ‘Tri-X 313’, which is susceptible to both races, and transplanted in a field infested with races 1 and 2 of F. oxysporum f. sp. niveum. Disease incidence for nongrafted and self-grafted Tri-X 313 (the control treatments) and Tri-X 313 grafted onto Ojakkyo citron did not differ significantly. Grafted watermelon plants produced greater weights and numbers of fruit than plants of the two control treatments. Nonpathogenic isolates of F. oxysporum and isolates of F. oxysporum f. sp. niveum colonized interspecific hybrid squash, bottlegourd, and grafted watermelon. The rootstocks evaluated, however, restricted movement of F. oxysporum f. sp. niveum into the watermelon scion, suppressed wilt symptoms, and increased fruit yields in an infested field.

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Silvicultural Management System Applied to Logged Forests in the Brazilian Amazon: A Case Study of Adaptation of Techniques to Increase the Yield and Diversity of Species Forestry

Diversity ◽

10.3390/d13110509 ◽

2021 ◽

Vol 13 (11) ◽

pp. 509

Author(s):

Agust Sales ◽

Marco Antonio Siviero ◽

Sabrina Benmuyal Vieira ◽

Jorge Alberto Gazel Yared ◽

Ademir Roberto Ruschel ◽

...

Keyword(s):

Management System ◽

Net Present Value ◽

Cost Benefit ◽

Forest Products ◽

Control Treatment ◽

Natural Forests ◽

Economic Returns ◽

Silvicultural Management ◽

The Cost

The existence of degraded forests is common in the Eastern Amazon. The maintenance of these forests standing and the recovery of their productivity play an important role in the conservation of biodiversity, storage and carbon sequestration. However, the management techniques currently employed are designed for natural forests in the first harvest cycle or lightly explored and do not apply adequately to forests that have gone through several harvest cycles. Therefore, adaptations and the establishment of new management criteria that take into account other characteristics of these types of forests are necessary to ensure their sustainability. The objective of this study was to propose a silvicultural management system that has the potential to recover and perpetuate the productivity of an intensively logged tropical forest. A forest census was carried out on 535.6 ha for trees with dbh ≥ 25 cm. With these data, the following two treatments were designed: (1) criteria: the BDq method was applied from B = 9.8 m2 ha−1, D = 100 cm and q = 2. The criteria for standing wood commercialization were, in this order, first, Health; second, Tree Stem; third, Tree Density and fourth, dbh ≥ 105 cm. (2) Control: the planning was in accordance with Brazilian regulations. For the cost–benefit and sensitivity analysis, the Net Present Value (NPV) was used and a projection of ±20% was made in the commercial price of standing wood. In the criteria treatment, a higher number of trees and species destined for the commercialization of standing wood was verified in relation to the control treatment, showing a greater diversity of species. In the criteria treatment, NPV was positive and superior to the control treatment in all scenarios. The proposed silvicultural management system with an object of an explored and enriched forest, with criteria for harvesting trees with a minimum cut diameter of 25 cm, proved to be viable to generate economic returns and with conservationist potential for the continuous supply of forest products and maintaining biodiversity.

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Zinc Biofortification in the Grains of Two Wheat (Triticum aestivum L.) Varieties Through Fertilization

Acta Agrobotanica ◽

10.5586/aa.7312 ◽

2020 ◽

Vol 73 (1) ◽

Author(s):

Shilpi Das ◽

M. Jahiruddin ◽

M. Rafiqul Islam ◽

Abdullah Al Mahmud ◽

Akbar Hossain ◽

...

Keyword(s):

Grain Yield ◽

Triticum Aestivum L ◽

Application Rate ◽

Control Treatment ◽

Wheat Grain ◽

Wheat Varieties ◽

Wheat Grains ◽

Crop Varieties ◽

Application Rates ◽

Zn Concentration

We examined the effects of zinc (Zn) fertilization on wheat, focusing on yield and biofortification in the grains of two wheat varieties. Five Zn rates, i.e., 0, 1.5, 3.0, 4.5, and 6.0 kg ha−1 applied as ZnSO4·7H2O (23% Zn), and two wheat varieties, i.e., ‘BARI Gom-25’ and ‘BARI Gom-26,’ were used in the study. All plant characteristics, except 1,000-grain weight and plant height, i.e., tillers plant−1, spikes m−2, spike length, spikelets spike−1, and grains spike−1, were significantly influenced by Zn fertilization. Treatment with 3.0 kg Zn ha−1 (Zn3.0) produced the highest grain yield (3.90 t ha−1), which was statistically similar to Zn4.5 and Zn6.0 treatments. The control treatment (Zn0) produced the lowest grain yield (2.99 t ha−1). The concentrations of N, Zn, and Fe were significantly and positively influenced by Zn treatment. The crop varieties did not differ significantly in terms of N and Zn concentrations. However, the grain Fe concentration was remarkably higher in ‘BARI Gom-26’ than in ‘BARI Gom-25.’ The grain N and protein concentrations increased linearly with the Zn application rate. The grain Zn concentration increased with Zn application rates in a quadratic line, indicating that the concentration of Zn in wheat grain increased with Zn fertilization; however, it attained a maximum value in the Zn4.5 treatment, after which it declined with higher rate of Zn application. The application of Zn at the rate of 4.5 kg ha−1 resulted in the highest Zn fortification (39.7 µg g−1) in wheat grains, which was 17.1% higher than in the control treatment. The response curve showed that 4.62 kg ha−1 for ‘BARI Gom-25’ and 3.94 kg ha−1 for ‘BARI Gom-26’ were the optimum Zn rates for achieving higher wheat grain yield. However, 5.5 kg ha−1 was the optimum Zn rate for obtaining higher Zn fortification in wheat grains.

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