scholarly journals Properly Timing Foliar-applied Fertilizers Increases Efficacy: A Review and Update on Timing Foliar Nutrient Applications to Citrus and Avocado

2013 ◽  
Vol 23 (5) ◽  
pp. 536-541 ◽  
Author(s):  
Carol J. Lovatt
Keyword(s):  
Foliar Application ◽  
Total Yield ◽  
Persea Americana ◽  
Nitrate Contamination ◽  
Soil Conditions ◽  
Negative Consequences ◽  
Runoff Water ◽  
Nutrient Demand ◽  
Tree Phenology ◽  
Fertilizer Rates

Foliar fertilization efficiently meets the nutrient demand of tree fruit crops during periods when soil conditions (low or high temperatures, low or excess soil moisture, pH, salinity) render soil-applied fertilizers ineffective, when nutrients (e.g., phosphate, potassium, and trace elements) become fixed in the soil, and when tree nutrient demand is high. Applying nutrients directly to leaves ensures that the metabolic machinery of the tree is not compromised by low availability of an essential nutrient. It should be noted that phloem mobile nutrients applied to the foliage are translocated to all tree parts, even feeder roots. Because foliar application of fertilizers can reduce nutrient accumulation in soil, runoff water, surface water (streams, lakes, ocean), and groundwater (drinking water supply), where they contribute to salinity, eutrophication, or nitrate contamination, with negative consequences to the environment and humans, it is highly desirable to replace soil-applied fertilizers at least in part with foliar-applied fertilizers. However, not all nutrients are taken up through leaves and, even if taken up, some nutrients are not phloem mobile. In addition, although foliar fertilizer rates are typically lower than soil fertilizer rates, application can be more costly. The goal has been to time the application of foliar fertilizers to key stages of citrus (Citrus sp.) and avocado (Persea americana) tree phenology when demand for the nutrient is likely to be high and especially when soil conditions are likely to compromise nutrient uptake by roots. This approach has proven successful for increasing yield, fruit size, and grower income even when the tree is not nutrient deficient by standard leaf analysis. Winter prebloom foliar-applied low-biuret urea was previously documented to increase total yield of both navel and ‘Valencia’ oranges (Citrus sinensis). Adaptation of this treatment to ‘Nules’ Clementine mandarin (Citrus reticulata) increased the yield of commercially valuable size fruit in two experiments. Foliar application of boron or low-biuret urea to ‘Hass’ avocado trees at the “cauliflower” stage of inflorescence development increased total yield; potassium phosphite applied at this stage of tree phenology increased the yield of commercially valuable size fruit.

scholarly journals 658 PB 066 EVALUATION OF PREPLANT AND FERTIGATED NITROGEN ON YIELD OF DRIP-IRRIGATED BELL PEPPERS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 527b-527
Author(s):  
W.H. Tietien ◽  
P. Nitzsche ◽  
W.P. Cowgill
Keyword(s):  
Total Yield ◽  
Weather Conditions ◽  
Nitrate Contamination ◽  
Fertilization Program ◽  
Edaphic Conditions ◽  
Bell Peppers ◽  
Loam Soil ◽  
Nitrogen Rates ◽  
Fertilizer Rates ◽  
Drip Fertigation

Environmental concerns about nitrate contamination of groundwater have prompted renewed interest in optimizing fertilizer rates. A field study was initiated to study the influence of preplant and drip fertigation rates of nitrogen on the yield of hell peppers grown on Quakertown (QkB) silt loam soil. Preplant nitrogen rates of 0, 56.7, and 113.5 kgha were incorporated into the plots before transplanting. The three fertigation rates (0, 17 and 34 Kg/mulched hectare) were injected through the drip irrigation starting one week after transplanting and repeated at three week intervals. Proplant nitrogen applications variably influenced early pepper yield. and did not significantly influence total yield. Early pepper yield was not influenced by drip fertigation rate, however, total yield increased as the fertigation rate increased. The dry weather conditions of the 1993 growing season may have influenced the responsc of pepper yield to the fertilizer treatments. Further studies are required to determine the optimum fertilization program for bell peppers grown under Northern New Jersey's edaphic conditions.

scholarly journals Timing Citrus and Avocado Foliar Nutrient Applications to Increase Fruit Set and Size

1999 ◽  
Vol 9 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Carol J. Lovatt
Keyword(s):  
Foliar Application ◽  
Persea Americana ◽  
Flower Initiation ◽  
Cumulative Yield ◽  
Phenological Stages ◽  
Inflorescence Development ◽  
Nutrient Demand ◽  
Washington Navel ◽  
Foliar Nutrient ◽  
Hass Avocado

The goal of this research was to identify the role essential nutrients play in the physiology of tree crops, and then to apply the nutrient as a foliar fertilizer to stimulate a specific metabolic process at phenological stages when nutrient demand is high. This approach has proven successful. A single winter prebloom foliar application of nitrogen as low-biuret urea [0.16 kg N/tree (0.35 lb N/tree)] to 30-year-old `Washington' navel orange (Citrus sinensis L. Osbeck) trees during flower initiation significantly increased yield and fruit number per tree for each of 3 consecutive years (P ≤ 0.05). The number of commercially valuable largesize fruit also increased significantly with yield increases (r2 = 0.88). Sodium tetraborate applied foliarly to `Hass' avocado (Persea americana Mill.) trees at the cauliflower stage of inflorescence development (elongation of inflorescence secondary axes, pollen and ovule development) increased the number of pollen tubes reaching the ovule, ovule viability and cumulative yield (P ≤ 0.05). Additional examples are presented.

scholarly journals Nitrogen Fertilization Strategies for the ‘Hass’ Avocado that Increase Total Yield Without Reducing Fruit Size

2016 ◽  
Vol 26 (4) ◽  
pp. 426-435 ◽  
Author(s):  
Jaime E. Salvo ◽  
Carol J. Lovatt
Keyword(s):  
Shoot Growth ◽  
Important Determinant ◽  
Total Yield ◽  
Fruit Size ◽  
Fertilizer Application ◽  
Persea Americana ◽  
Phenological Stages ◽  
Tree Phenology ◽  
Hass Avocado ◽  
N Demand

Effects of nitrogen (N) fertilizer application times and rates on ‘Hass’ avocado (Persea americana) yield and fruit size were determined to resolve whether a single dose of soil-applied N [1x N (25 lb/acre)] at each of the five key stages of tree phenology (January, April, July, August, and November) (control) was as efficacious as soil-applied 2x N (50 lb/acre) at one or two key stages or soil- or foliar-applied 3x N (75 lb/acre) at only one stage. All trees received soil-applied N at 125 lb/acre as ammonium nitrate (NH4NO3) annually; trees receiving 2x or 3x N received the remaining N divided evenly at the same phenological stages (months) as trees receiving five 1x N applications. The importance of supplying N during the summer, when June drop, exponential fruit growth, vegetative shoot growth, and floral initiation occur, was determined by testing soil-applied 0.8x N in July plus August only (40 lb/acre N as NH4NO3 annually). Application time proved an important determinant of total yield. Yield of commercially valuable size (CVS) fruit was correlated with total yield (r = 0.80, P < 0.0001). Four-year cumulative total yields were equal for trees receiving soil-applied 1x N at five key phenological stages and trees receiving soil-applied 2x N in April and 18.75 lb/acre N at the four other stages (months). However, trees receiving soil-applied 2x N in April plus November and only 8.3 lb/acre N in the three other months, in particular July and August, had significantly lower 4-year cumulative total yields (P = 0.0362). Additional evidence of the importance of meeting avocado tree N demand in the summer is that trees receiving only 40 lb/acre N split in July plus August produced 4-year cumulative total yields equal to trees receiving 25 lb/acre N at the five key phenological stages; lower annual N would reduce fertilizer expense and protect the environment.

Nutrient-Use Patterns in Nursery Crops

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 557a-557
Author(s):  
Mary Ann Rose ◽  
Barbara Biernacka
Keyword(s):  
Nutrient Retention ◽  
The United States ◽  
Soil Conditions ◽  
Woody Ornamentals ◽  
Use Patterns ◽  
Nutrient Demand ◽  
Nutrient Use ◽  
Fertilizer Recommendations ◽  
Retention Characteristics ◽  
Practical Constraints

Long-standing fertilizer recommendations for field-grown nursery and landscape ornamentals are based on maximizing growth, not nutrient efficiency. Further, these recommendations fall short because of failure to consider 1) the extent of crop nutrient removal, 2) varying nutrient retention characteristics of soils across the United States, and 3) a body of research that suggests that woody ornamentals have a limited response to fertilization under most soil conditions. Concern for the environmental impact of fertilization justifies a reevaluation of current nursery fertilization practices, as well a discussion of the practical constraints on the adoption of new approaches, e.g., nutrient demand-driven fertilization. Research on the nutrient use patterns of woody plants will be reviewed with emphasis on implications for increasing fertilization efficiency. OSU research on water availability and nutrient-use interactions also will be presented.

scholarly journals Optimal Nutrient Concentration Ranges of ‘Hass’ Avocado Cauliflower Stage Inflorescences—Potential Diagnostic Tool to Optimize Tree Nutrient Status and Increase Yield

HortScience ◽  
2017 ◽  
Vol 52 (12) ◽  
pp. 1707-1715 ◽  
Author(s):  
Salvatore Campisi-Pinto ◽  
Yusheng Zheng ◽  
Philippe E. Rolshausen ◽  
David E. Crowley ◽  
Ben Faber ◽  
...  
Keyword(s):  
Nutrient Concentration ◽  
Fruit Set ◽  
Fruit Size ◽  
Nutrient Status ◽  
Persea Americana ◽  
Nutrient Concentrations ◽  
Full Bloom ◽  
Nutrient Analysis ◽  
Tree Phenology ◽  
Hass Avocado

Optimizing ‘Hass’ avocado (Persea americana Mill.) tree nutrient status is essential for maximizing productivity. Leaf nutrient analysis is used to guide avocado fertilization to maintain tree nutrition. The goal of this research was to identify a ‘Hass’ avocado tissue with nutrient concentrations predictive of yields greater than 40 kg of fruit per tree. This threshold was specified to assist the California avocado industry to increase yields to ≈11,200 kg·ha−1. Nutrient concentrations of cauliflower stage inflorescences (CSI) collected in March proved better predictors of yield than inflorescences collected at full bloom (FBI) in April, fruit pedicels (FP) collected at five different stages of avocado tree phenology from the end of fruit set in June through April the following spring when mature fruit enter a second period of exponential growth, or 6-month-old spring flush leaves (LF) from nonbearing vegetative shoots collected in September (California avocado industry standard). For CSI tissue, concentrations of seven nutrients, nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), sulfur (S), zinc (Zn), and copper (Cu) were predictive of trees producing greater than 40 kg of fruit annually. Conditional quantile sampling and frequency analysis were used to identify optimum nutrient concentration ranges (ONCR) for each nutrient. Optimum ratios between nutrient concentrations and yields greater than 40 kg per tree were also derived. The high nutrient concentrations characterizing CSI tissue suggest current fertilization practices (timing or amounts) might be causing nutrient imbalances at this stage of avocado tree phenology that are limiting productivity, a possibility that warrants further investigation. Because CSI samples can be collected 4–6 weeks before full bloom, nutritional problems can be addressed before they affect flower retention and fruit set to increase current crop yield, fruit size, and quality. Thus, CSI nutrient analysis warrants further research as a potential supplemental or alternative tool for diagnosing ‘Hass’ avocado tree nutrient status and increasing yield.

scholarly journals Herbivory modulates soil CO2 fluxes after windthrow: a case study in temperate mountain forests

2019 ◽  
Vol 139 (3) ◽  
pp. 383-391 ◽  
Author(s):  
Mathias Mayer ◽  
David Keßler ◽  
Klaus Katzensteiner
Keyword(s):  
Soil Carbon ◽  
Plant Community ◽  
Plant Communities ◽  
Soil Conditions ◽  
Negative Consequences ◽  
Mountain Forests ◽  
Exclusion Experiment ◽  
Vegetation Shifts ◽  
Ungulate Herbivory ◽  
Carbon Losses

AbstractUngulate herbivory can alter functional plant communities of early-successional forest ecosystems. The consequences of such vegetation changes on soil carbon cycling are still not fully understood. Here, we used an ungulate exclusion experiment to investigate how different levels of herbivory and associated changes in vegetation succession modulate soil CO2 efflux and its heterotrophic and autotrophic sources following windthrow in temperate mountain forests. Our results indicate that only high levels of ungulate herbivory and associated vegetation shifts from tree to rather grass dominated plant communities affect soil CO2 fluxes. We did not find evidence that a moderate herbivory level and accompanied smaller shifts in the functional plant community affect soil CO2 fluxes. A greater soil CO2 efflux under the influence of high herbivory pressure was primarily attributed to accelerated heterotrophic respiration, likely due to warmer soil conditions. Moreover, autotrophic respiration from grass roots and associated microbial communities is suggested to contribute to higher soil CO2 fluxes. We conclude that intense herbivory and accompanied successional changes in the functional plant community enhance soil carbon losses following forest windthrow. This might have negative consequences for the soil carbon stocks and for the climate system.

scholarly journals Effect of late-season nitrogen fertilization on grain yield and on flour rheological quality and stability in common wheat, under different production situations

2016 ◽  
Vol 11 (2) ◽  
pp. 107 ◽  
Author(s):  
Massimo Blandino ◽  
Federico Marinaccio ◽  
Amedeo Reyneri
Keyword(s):  
Grain Yield ◽  
Common Wheat ◽  
Storage Proteins ◽  
Foliar Application ◽  
N Fertilization ◽  
Soil Conditions ◽  
N Application ◽  
Late Season ◽  
Technological Quality

The increasing demand for a high and homogeneous technological quality of common wheat (<em>Triticum aestivum</em> L.) points out the necessity of improving wheat with by a higher protein (GPC) and gluten content, strength of dough (W) and dough stability. Among the current crop practices, late-season nitrogen (N) fertilization, from heading to flowering, is generally considered the practice that has the most effects on the storage proteins and technological quality of the grain. In order to explore the influence late-season N application can have on the dough properties and on the formation of homogeneous lots in more detail, a research was set up between 2007 and 2013, over 6 growing seasons at different sites in North West Italy using the Bologna cultivar in each of the trials. Three different late-season N fertilization strategies were compared: T1, control without a late distribution of N; T2, foliar N fertilization at flowering; T3, top-dress granular soil fertilization at the beginning of heading. A randomized complete block experimental design with four replicates was adopted. The grain yield, GPC, W and P/L indexes were analyzed. Moreover, the rheological and enzymatic properties of the samples were studied using a Mixolab® analyser (Chòpin Technologies, Paris, France). Grain yield was found to be unaffected by the fertilization treatments, while the late N application (T2, T3) significantly increased GPC. Only the granular N fertilization (T3) increased the W index compared to T1, while the P/L index was not affected by any of the fertilization strategies. Furthermore, the T3 strategy was always more effective in reducing the variability of the W index than the T2 and the T1 strategies. Water absorption and dough development time were higher in T3, than in T1, while intermediate results were reached for T2. The effect of late-season N fertilization was also significant on the starch behaviour of the dough, as an increase in starch gelatinization and retrogradation was observed. In short, the top-dress granular N fertilizer applied at the beginning of heading (T3) led to a more constant increase in GPC and flour rheological quality than the foliar application. Moreover, the adoption of this fertilization strategy resulted in a reduction in qualitative variability under different environmental and soil conditions.

scholarly journals Foliar Application: A Thriving and Flourishing Domain in Agriculture

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Pushpa C Tomar
Keyword(s):  
Foliar Application ◽  
Foliar Spray ◽  
Soil Condition ◽  
Research Area ◽  
Water Soluble ◽  
Soil Conditions ◽  
Sowing Time ◽  
Ongoing Research ◽  
Soil Application ◽  
Solution Condition

Foliar Application seems to be an upcoming and ongoing research area especially in the field of agriculture. This is been in practice in various parts of the world and proved its positive results in its field [1,2]. Foliar application can be explained as spraying the suitable fertilizer solution (condition is, that it should be water soluble) on the surface of the leaves of growing plants [3]. This practice not only saves quantity of fertilizer used but also improves the uptake of a particular micronutrient by the crops and boosts the yield too. Interaction between crop’s genetic potential and the environment in which it grows is detrimental for the yield of a crop [4]. Soil application of nitrogen is a conventional method to supply nitrogen to plants and for improvement in any field adhering to the old ways will not be a better option [4]. In some instances, the availability of urea becomes inadequate for the farmers at sowing time. In such situation the foliar application of plant nutrient is effective and economical for some crops [5]. It has been shown in some studies that uptake of micronutrients directly from plants is more rapid and quicker for better results in yields than soil application[1]. As mentioned above, that the fertilizer should be water soluble for foliar spray and moreover, it should also be noted that the particular crop plant also should be suitable for aerial spray. The best results of foliar application also depends on the soil condition as if soil conditions are unfavourable when micronutrients are needed, it may be desirable to make foliar applications of the plant nutrients

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