Xylem Plugging, Hydraulic Conductivity, Growth, and Yield of Citrus Trees Affected by Citrus Declinamiento in Argentina

Huanglongbing (HLB) causes citrus root systems to decline, which in turn contributes to deficiencies of essential nutrients followed by decline of the canopy and yield. This study was conducted on a 6-year-old ‘Valencia’ [Citrus sinensis (L.) Osb.] on Swingle rootstock (Citrus paradisi Macf. × Poncirus trifoliata (L.) Raf.) trees in a commercial grove near Immokalee, FL, to evaluate the effects of foliar applications of selected essential nutrients (N, K, Mn, Zn, B, and Mg) on growth and productivity of citrus trees infected with Candidatus Liberibacter asiaticus (CLas), the pathogen putatively associated with HLB in Florida. Mn, Zn, B, and Mg were applied in all experiments to drip at 0×, 0.5×, 1.0×, and 2.0×/spray of what has been traditionally recommended in Florida to correct deficiencies. Treatments were applied foliarly 3×/year with the sprays occurring during each growth flush for 5 years (2010–14). Thus, the 0×, 0.5×, 1.0×, and 2.0×/spray treatments resulted in 0×, 1.5×, 3.0×, and 6.0×/year to correct deficiencies. MnS04 and ZnSO4 were applied with or without KNO3 and in separate experiments were compared with Mn3(PO3)2 and Zn3(PO3)2, respectively. Disease incidence, foliar nutrient content, canopy volume, and yield were measured. At the beginning of the experiment, foliar N, P, Ca, Mg, Cu, and B were in the sufficient range and K, Mn, Zn, and Fe were slightly low. Disease incidence was very high with 83% and 98% of trees testing positive for CLas in 2010 and 2014, respectively. Nutrients that are not mobile or have limited mobility in plants, namely Mn, Zn, and B, demonstrated an increase in foliar concentration immediately after spray and in the annual averages. Foliar K increased from the deficient to the sufficient level by KNO3 sprays, but the mobile nutrients N and Mg did not show an increase in foliar levels, indicating that intraplant transport occurs in the presence of HLB. Foliar KNO3 application had a stronger effect on growth than yield. Yield was most strongly affected by application of MnSO4 where yield of the 3×/year treatment was 45% higher than that of the unsprayed control, but yield declined by 25% for the 6×/year treatment. Yield within 95% of the maximum occurred with foliar Mn concentrations of 70–100 µg·g−1 dry weight when Mn was applied as MnSO4, which is at the high end of the traditionally recommended 25–100 µg·g−1 dry weight range. The phosphite form of Mn [Mn3(PO3)2] depressed yield by an average of 25% across all application concentrations. Zn, B, and Mg did not significantly impact yield. Canopy volume demonstrated concave relationships across application concentrations for MnSO4 and ZnSO4 without KNO3 and Mn3(PO3)2, Zn3(PO3)2, Boron, and MgSO4 with KNO3, with the minimum occurring near the 3×/year application concentration. These data indicate a complex interaction in the amount of nutrients applied and their corresponding effects on foliar concentration, growth, and yield for HLB-affected trees. The results of this study at least partially explain the current confusion among scientists and the commercial industry in how to manage nutrition of HLB-affected citrus trees. The traditionally recommended approaches to correcting nutrient deficiencies need to be reconsidered for citrus with HLB.

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Enhancing the Solubility and Reclamation Efficiency of Gypsum with H2SO4

Cercetari Agronomice in Moldova ◽

10.2478/cerce-2019-0013 ◽

2019 ◽

Vol 52 (2) ◽

pp. 128-140

Author(s):

A.I. Saqib ◽

K. Ahmed ◽

G. Qadir ◽

M.Q. Nawaz ◽

A.R. Naseem

Keyword(s):

Hydraulic Conductivity ◽

Bulk Density ◽

Root Zone ◽

Chemical Properties ◽

Maximum Growth ◽

Growth And Yield ◽

Wheat Crop ◽

Optimum Level ◽

Sodic Soils ◽

Combined Application

Abstract An effective reclamation procedure of saline sodic soils is removal of undesirable Na+ by addition of some Ca2+ source paralleled with leaching of this sodium out of root zone. Nevertheless, gypsum being a direct source of Ca2+ is relatively insoluble in water. Its solubility can be increased with addition of H2SO4. Therefore, three years (2015 to 2018) study was plan to find out the optimal and economical level of H2SO4, which can increase the solubility and reclamation efficiency of gypsum for saline sodic soil in rice wheat crop-ping rotation. Treatments included were: T1, Control, T2, gypsum @ 100% of GR, T3, gypsum @ 100% of GR+10 kg H2SO4 acre−1, T4, gypsum @ 100% of GR+50 kg H2SO4 acre−1, T5, gypsum @ 100% of GR+100 kg H2SO4 acre−1. Before start of study, soil had pHs = 8.85, ECe = 4.85 (dS m−1), SAR = 43.82 (mmol L−1)1/2, GR = 4.10 (t. acre−1), BD = 1.65 (Mg m-3), HC = 0.33 (cm hr−1). Experiment was laid out in RCBD with three replications. Sulfuric acid and gypsum were applied (once) at the start of study in the respective treatment plots. Recommended dose of fertilizers, 150-90-60 NPK kg ha−1 for rice (Shaheen Basmati) and 160-114-60 NPK kg ha−1 for wheat (Faisalabad, 2008) was applied. Yield and yield determining attributes of each crop were recorded at physical maturity. After harvest of each crop, soil samples were collected and were analyzed for ECe, pHs, SAR, bulk density and hydraulic conductivity. Pooled data analysis revealed that maximum growth and yield determining factors of rice and wheat were recorded where gypsum was applied with H2SO4 at the rate of 50 and 100 kg acre−1. Soil physical and chemical properties, i.e. pHs, ECe, SAR bulk density and hydraulic conductivity were also substantially improved with combined application of gypsum and H2SO4 at the end of study. Both levels of H2SO4 at the rate of 50 and 100 kg acre−1 with gypsum proved equally to be the best in enhancing the solubility and reclamation efficiency of gypsum and showed the statistically (p≤ 0.05) similar results in increasing the yield of rice and wheat crop and improving the soil physical and chemicals properties. Therefore, H2SO4 at the rate of 50 kg acre−1 is recommended as most economical and optimum level, which can be used with gypsum as an effective ameliorative strategy for the salt affected soils.

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Citrus Tree Stresses: Effects on Growth and Yield

EDIS ◽

10.32473/edis-hs393-2008 ◽

2008 ◽

Vol 2008 (5) ◽

Author(s):

James Syvertsen ◽

Edward A. Hanlon

Keyword(s):

Environmental Conditions ◽

Management Practices ◽

Plant Stress ◽

Growth And Yield ◽

Citrus Tree ◽

Fact Sheet ◽

Citrus Trees

HS-1138, a 6-page illustrated fact sheet by J. Syvertsen and E.A. Hanlon, provides information dealing with citrus responses to environmental conditions for professionals involved with citrus management practices. It explains how citrus trees respond to changes in availability of water and nutrients; discusses plant-stress situations and their effects on citrus growth and productivity; and discusses the balance between roots and shoots. Includes references. Published by the UF Department of Horticultural Sciences, May 2008.

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Water Infiltration in Fall Broccoli

HortScience ◽

10.21273/hortsci.41.4.998b ◽

2006 ◽

Vol 41 (4) ◽

pp. 998B-998

Author(s):

Carlene A. Chase ◽

Odemari S. Mbuya ◽

Danielle D. Treadwell

Keyword(s):

Hydraulic Conductivity ◽

Cover Crops ◽

Organic Production ◽

Weed Suppression ◽

Water Infiltration ◽

Growth And Yield ◽

Weed Biomass ◽

Central Florida ◽

Live Oak ◽

Weed Infestation

The effect of living mulches (LM) on weed suppression, crop growth and yield, and soil hydraulic conductivity were evaluated in broccoli in North Central Florida at Citra and in North Florida at Live Oak, using organic production methods. `Florida 401' rye, `Wrens Abruzzi' rye, black oat, and annual ryegrass, were either mowed or left untreated and compared with weedy and weed-free controls. Cover crop biomass was highest with `Florida 401' at both locations, intermediate with black oat and `Wrens Abruzzi', and lowest with ryegrass. The greatest weed infestation occurred with the weedy control. In Citra, ryegrass decreased weed biomass by 21% compared with ≈45% by the other LM with no differences due to mowing. However, at Live Oak, mowed LM and the weedy control had similar amounts of weed biomass; whereas unmowed LM had 30% to 40% less weed biomass than the weedy control. At both locations, broccoli heights were greatest with the weed-free control, intermediate with the cover crops, and lowest with the weedy control. Total above-ground broccoli biomass and marketable weight of broccoli at Live Oak, and number of marketable heads at both locations, were unaffected by the LM. At Citra, total broccoli biomass with LM and the weedy control decreased in a similar manner, so that total broccoli biomass was highest with the weed-free control. Ryegrass and the weedy control suppressed marketable broccoli weight by 24%; however, greater decrease in marketable weight (39% to 43%) occurred with `Florida 401', `Wrens Abruzzi', and black oat. At both locations, mowing of LM had no effect on broccoli growth or yield. There was no difference in saturated hydraulic conductivity among treatments.

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Block hydraulic conductivity of cross-bedded fluvial sediments

Water Resources Research ◽

10.1029/94wr01094 ◽

1994 ◽

Vol 30 (10) ◽

pp. 2665-2678

Author(s):

Marc F. P. Bierkens

Keyword(s):

Hydraulic Conductivity ◽

Fluvial Sediments

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Photosynthetic responses of citrus trees to soil flooding

Physiologia Plantarum ◽

10.1034/j.1399-3054.1991.810102.x ◽

1991 ◽

Vol 81 (1) ◽

pp. 7-14 ◽

Cited By ~ 4

Author(s):

Joseph C. V. Vu ◽

George Yelenosky

Keyword(s):

Soil Flooding ◽

Photosynthetic Responses ◽

Citrus Trees

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2016 Planting and Annual Cultural Maintenance Costs for Reset-Replacement Trees in a Florida Citrus Grove

EDIS ◽

10.32473/edis-fe995-2016 ◽

2016 ◽

Vol 2016 (7) ◽

Author(s):

Marina Burani Arouca ◽

Stephen Hubbard Futch ◽

Ariel Singerman

Keyword(s):

Citrus Grove ◽

Maintenance Costs ◽

Cultural Maintenance ◽

Florida Citrus ◽

Citrus Trees

We provide estimates for the costs of planting and maintaining reset citrus trees in Florida in the era of HLB, The estimates are useful as a benchmark but also to inform industry stakeholders and policymakers regarding the costs growers have to incur in when planting new trees.

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Growth and yield of okra (Abelmoschus esculentus (L.) Moench) grown in the marginal upland area of Sta. Rita, Samar as influenced by different planting densities and mulching materials

Annals of Tropical Research ◽

10.32945/atr39sa4.2017 ◽

2017 ◽

pp. 44-54

Author(s):

Zenaida Gonzaga ◽

Warren Obeda ◽

Ana Linda Gorme ◽

Jessie Rom ◽

Oscar Abrantes ◽

...

Keyword(s):

Bare Soil ◽

Abelmoschus Esculentus ◽

Growth And Yield ◽

Planting Density ◽

Rice Hull ◽

Plastic Mulch ◽

Lady’S Finger ◽

Materials Used ◽

Set Up ◽

A Minor

Okra or Lady’s finger, botanically known as Abelmoschus esculentus (L.) Moench, is a tropical and sub-tropical indigenous vegetable crop commonly grown for its fibrous, slimy, and nutritious fruits and consumed by all classes of population. It has also several medicinal and economic values. Despite its many uses and potential value, its importance is under estimated, under-utilized, and considered a minor crop and little attention was paid to its improvement. The study was conducted to evaluate the effects of different planting densities and mulching materials on the growth and yield of okra grown in slightly sloping area in the marginal uplands in Sta. Rita, Samar, Philippines. A split-plot experiment was set up with planting density as main plot and the different mulching materials as the sub-plot which were: unmulched or bare soil, rice straw, rice hull, hagonoy and plastic mulch. Planting density did not significantly affect the growth and yield of okra. Regardless ofthe mulching materials used, mulched plants were taller and yielded higher compared to unmulched plants. Moreover, the use of plastic mulch resulted to the highest total fruit yield. The results indicate the potential of mulching in increasing yield and thus profitability of okra production under marginal upland conditions.

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