Root respiration and soil aeration status of blueberries (Vaccinium SP.)

Plants of 3 progenies of Vaccinium sp. were utilized in exised root respiration studies over a range of O₂ levels from 2.5 to 21%. Root respiration of plants from an intraspecific V. ashei Reade progeny, Powderblue x T‐142, were approximately half that of two other progenies, one with germplasm of V. ashei and V. constablaei Gray and the other with germplasm of V. corymbosum L., V. ashei and V. constablaei. The V. ashei progeny was unaffected by reduced O levels under laboratory conditions, whereas the other two progenies showed significantly reduced root respiration rates, particularly at the 2.5% O₂ level. However, soil O₂ levels were near 21% at a depth of 15 cm under established blueberry bushes indicating that root respiration per se may be a more important criteria in blueberry adaptation to soil and environmental stresses than actual soil oxygen status.

Root respiration measurements at 21% O₂ may provide a useful tool in screening blueberry progenies for adaptation to climatic and soil induced atmospheric stresses, and perhaps other stresses.     

Nitrification and utilization of fertilizer nitrogen by highbush blueberry

Nitrification rates and nitrogen (N) recovery by 3 year‐old highbush blueberry ( Vaccinium corymbosum L. cv. Bluecrop) were compared following applications of ammonium sulfate with or without the nitrification inhibitor dicyandiamide (DCD) on a sandy loam soil with pH 4.8. Ammonium sulfate solutions containing 7.9 grams N (10.2 atom % ¹⁵N), with or without 0.6 g DCD, were applied to the soil surface beneath bushes. Concentrations of fertilizer derived nitrate were significantly lower in DCD treated soils 2 weeks following application, but DCD had no effect on total nitrate levels or fertilizer derived nitrate later in the season. Uptake of fertilizer‐N by blueberry plants was observed by collecting fruit during the growing season and assessing N partitioning within whole plants at the end of the season using ¹⁵N as a label for fertilizer N. The DCD had no effect on fertilizer derived or total N levels in plants. Plants recovered an average of 3% of applied N by the end of the season.     

Assessing the impact of cultivation and plant domestication of highbush blueberry (Vaccinium corymbosum) on soil properties and associated plant-parasitic nematode communities

We investigated the interactive effects of plant domestication and perennial cultivation on diversity and richness of plant-parasitic nematode (PPN) communities associated with highbush blueberry (Vaccinium corymbosum). Rhizospheric soil of V. corymbosum plants was sampled in coupled wild and cultivated sites within the Pinelands National Reserve. Although PPN diversity was higher in cultivated plant soil samples, richness was higher in wild plant soil samples. The most important soil properties, iron and calcium, were associated with cultivated soil and were the best predictors of genera abundance patterns. Nematodes in the genus Criconemoides were 187× more abundant in wild sites than cultivated and thus, were significant indicators of wild sites. In this study cultivation of V. corymbosum appears to benefit the PPN community but alters the community composition considerably.     

Response of ‘Bluecrop’ Highbush Blueberry to Boron Fertilization

The objective of this experiment was to examine the vegetative and generative responses of highbush blueberry to boron fertilization. The study was carried out in 2002–2003 in Central Poland on mature ‘Bluecrop’ blueberries (Vaccinium corymbosum L.) planted at a spacing of 3 × 1 m on a sandy loam soil with pH value of 3.9 and low hot water soluble boron status. Blueberries were soil- or foliar-supplied with boron. Foliar boron sprays were done four times per season: at the beginning of blooming, at petal fall, and three and six weeks after the ending of flowering. In each spray treatment, boron was applied at a rate of 0.2 kg ha^?1. Soil boron was applied at the stage of bud break at a rate of 2 kg ha^?1. Plants untreated with boron served as control. The results showed that boron fertilization increased boron levels in flower and leaf tissues. This treatment, regardless of boron application mode, did not affect plant vigor, the number of flowers per cane, fruit set, nor yield. Also mean fruit weight and berry firmness were not influenced by boron fertilization. Fruit of boron-supplied blueberries had higher soluble solids concentrations than those of the control plants. It is concluded that boron requirements of highbush blueberry are relatively low compared to most fruit crops and that critical leaf boron concentrations of ‘Bluecrop’ blueberry are below 15 mg kg^?1 DW.     

Plant Nitrogen Status of Southern Highbush Blueberry (Vaccinium corymbosum L. Interspecific Hybrid) Grown in Pine Bark Amended Soils with Varying Rates of Nitrates

An experiment evaluating three fertilizer types (granular, liquid, and controlled released fertilizer) with nitrate ranging from 0% to 44% was conducted over two seasons on southern highbush blueberry ‘Star’ at the University of Georgia’s blueberry farm in Alapaha, GA. The objective was to identify the effect on fruit quality, plant growth, and plant tissue nitrogen status. This work demonstrated that the applications of fertilizer had similar effects on fruit quality and growth for ‘Star’ grown in sandy organic soils. In addition, fertilizers with 36.5% or 44% nitrate did not appear to have significant accumulation of nitrate in the leaves. Soil analysis revealed that none of the fertilized soils significantly increased cation exchange capacity; however, soil pH increased in soils with 36.5% and 44% nitrate applications. This suggests these nitrate levels will require continued soil monitoring and possible soil acidification to maintain appropriate soil pH for blueberry production (4.0–5.5 pH).     

Influence of micronutrient and phoshorous levels and chelator to iron ratio on growth,chlorosis, and nutrition of Vaccinium ashei reade and V. elliottii chapman

‘Tifblue’ (V. ashei Reade) and US 280 (V. elliotti Chapman) blueberry plants were exposed to 2×2×2 factorial treatments of high and low phosphate and micronutrients (Cu, Zn, Mn, and B) and excess or stoichiometric concentrations of a chelator (EDDHA) added to Fe(NO₃)₃ in pH 6.8 solution cultures. Phosphorous was applied at 20 (low) or 400 (high) μM levels, micronutrients at low or high levels and either a 1:1 or 10:1 ratio of chelator to Fe concentrations.

Excess chelator in the nutrient solution always increased the severity of chlorosis except for US 280 plants grown under low P and stoichiometric chelator where neither micronutrient level resulted in chlorosis. Increased P concentration usually resulted in more severe chlorosis except for ‘Tifblue’ plants grown under low micronutrients and stoichiometric chelator where chlorosis did not develop with either P level. ‘Tifblue’ and US 280 differed in there response to excess solution Cu levels.

Unlike highbush blueberries (V. corymbosum L.), these two species of blueberries responsed to excess chelator in a manner similar to that reported for monocots.     

Phosphorus Fertilizer use in Pineapple Cultivation with in situ Residues Burning on Organic Soils

Abstract

In Malaysia, pineapples are grown on peat soils, but most phosphorus (P) fertilizer recommendations are made without due quantification of P uptake; the distribution of P in roots, stem, leaves, peduncle, fruit, and crown; or loss through leaching even though P retention in peat soils is low. This study was conducted to determine applied P‐use efficiency under a conventionally recommended fertilization regime in pineapple cultivation with in situ residues burning before replanting. Results showed that most of the P uptake in pineapple can be found in the fruit, stem, leaves, and crown, but the general trend of P distribution was in the order of fruits>leaves>stem>crown>peduncle>roots. Phosphorus recovery in pineapple cultivation was about 40%, and this low recovery was attributed to leaching. Hence, fertilizer recommendations need to take into consideration P loss through leaching. This will help to increase P‐use efficiency because it is not possible to build up P content of peat soils. As a result, the need to assess the possibility of side‐dress applications of phosphatic fertilizers on peat soil is necessary.     

Elemental leaf content and deficiency symptoms in rabbiteye blueberries: 1. Nitrogen

Rabbiteye blueberries grown in sand culture were subjected to varying levels of N fertilization (0 ‐ 81 mg N/liter) applied in aqueous solution at the rate of 250 ml/plant daily. Essential elements other than N were kept constant. Shoot growth and leaf concentration of N, P, K, Mg, Ca, Mn, Fe, Cu, B, Zn, Co, and Al were determined. Shoot growth and percent leaf N increased with increased N levels. Shoot growth increased little at N fertilization levels of 0 ‐ 9 mg/ liter but increased rapidly at higher rates. N content in leaves followed a quadratic curve, with % N in leaves increasing more rapidly from 0 to 27 mg N/liter than from 27 to 81 mg N/liter fertilization levels. Leaf concentration of K, Ca, Mg, Mn, B, and Ca decreased linearly as N levels increased. Total content of all elements increased as N fertilization increased. Visual N deficiency became increasingly evident as % N content decreased below 1.4% N.

Nitrogen, the most utilized element in plants, is usually the first to become deficient in sandy soils low in nutrient content (1). Rabbiteye blueberries (Vaccinium ashei Reade) are often grown on acidic, sandy, upland coastal plains soils that are low in cation exchange capacity, organic matter content, and available nutrients. In these acidic soils, NH₄N is more available than in neutral soils (2). The NH₄N source appears to be more suitable for blueberry growth, resulting in greater nutrient uptake, plant growth, and % N of leaf tissue than did the NO₃N sources (5,6).

Nitrogen deficiency symptoms in rabbiteye blueberries are characterized by small, yellow and/or red leaves and stunted plants (3). Since young rabbiteye plants are very sensitive to fertilizer, similar chlorosis symptoms (yellowing or reddening of leaves) can be associated with over‐fertilization, possibly due to root damage (7). Cain (2) found that leaves from healthy container‐grown highbush (V. corymbosum L.) blueberry plants contained about 2% N and higher levels of K and Ca than field‐grown plants. Greenhouse and Field studies indicate that leaf N content in rabbiteye blueberries is usually lower, ranging from about 1.5 to 1.8 (3,7,8). Increased N fertilization decreased the nutrient uptake of other essential elements (Ca and Mg) in rabbiteye blueberries (6). In highbush, Popenoe (4) indicated that a depression of P and K might occur under conditions of high N levels.

This study was initiated to ascertain the effect of NH₄N fertilization levels on uptake patterns of essential elements and to determine the relationships of N fertilization, leaf N content, plant growth, and visible deficiency symptoms.     

不同土壤改良物质对越桔叶片酶活性影响的研究

黑土中加入有机物料和硫磺粉(S),对越桔叶片的过氧化氢酶、过氧化物酶、硝酸还原酶都产生显著影响,不同处理有较大差异,其中,加入苔藓、苔藓和草炭及只加入1.5kgS-2kgS的处理,叶片的过氧化氢酶活性较高,过氧化物酶和硝酸还原酶活性较低,叶片生长发育良好。     

Characterization of Bioactive Compounds in Blueberry and Their Impact on Soil Properties in Response to Plant Biostimulants

ABSTRACT

Vaccinium corymbosum L. (Ericaceae) is a highly valued fruit crop and the most common type of blueberry grown in Chile. Plant growth and yield crop production are affected by agricultural practices and different soil parameters including chemical and biological properties. We performed a field assay to assess the effect of the inoculation with a mixture of 10 microorganisms and the addition of humic substances on the growth of blueberry, quality of fruit and soil chemical and biological properties. Two years after planting, the microbial consortium was more effective than the addition of humic substances recording a 35% increase in shoot dry weight, 70% increase in root dry weight and 104% on total fruits yield compared to the control plants. Total polyphenols and ferric reducing antioxidant power (FRAP) in fruit were increased on humic substance treatment. The combination of both factors increased by 18% organic matter and 60% cation exchange capacity. Soil respiration, microbial biomass C and enzyme activities (dehydrogenase, phosphatase, β-glucosidase, urease, and protease) to a greater extent than individual application. The combined treatment, involving microbial inoculant and humic substances, had an additive effect on improving the biochemical and microbiological quality of the soil.     

Wheat and Rye Differ in Drymatter Partitioning,Shoot-Root Ratio and Water Use Efficiency Under Organic and Inorganic Soils

Shoot-root ratio (S:R), dry matter partitioning (DMP), and water use efficiency (WUE) response of wheat (Triticum aestivum L.) vs. rye (Secale cereale L.) was investigated under organic [organic compost (OC), Miracle Grow (MG), sunshine peat moss (SPM), and Garden Basic peat humus (GBPM)], and inorganic soils [canyon soil (CS) and amarillo soil (AS)] in pot experiment at Dryland Agriculture Institute, West Texas A&M University, College Station, Texas, USA, during winter 2009–2010. The experiment was performed in completely randomized design (CRD) with three repeats. The objective of this experiment was whether S:R, DMP, and WUE of wheat versus rye differ under organic and inorganic soils. The results revealed that both crops responded differently in terms of S:R, DMP, and WUE under different organic and inorganic soils. Wheat had higher WUE than rye at different growth stages. Among the soil types, the three organic soils (MG, SPM, and GBPS) had higher WUE than the two inorganic (CS and AS) soils. The higher WUE of both crops when grown in organic soils such as MG, SPM, and GBPS was due to the higher dry matter partitioning to shoots and roots. The total dry weight plant^?1 showed positive relationship with WUE.     

Assessing genetic diversity of wild southeastern North American <Emphasis Type="Italic">Vaccinium</Emphasis> species using microsatellite markers

Wild species representatives from Northwestern, Central and Southern Florida, and neighboring U.S. states were collected in multiple United States Department of Agriculture (USDA) exploration expeditions and are being preserved at the USDA, Agricultural Research Service, National Clonal Germplasm Repository in Corvallis, Oregon. Germplasm from these southeastern regions of North America is particularly vulnerable to loss in the wild due to encroachment of human development in key habitats and biotic and abiotic stresses from climate change. Fourteen simple sequence repeats (SSRs), previously developed from the highbush blueberry (Vaccinium corymbosum) cultivar ‘Bluecrop’, were used to estimate genetic diversity and genetic differentiation of 67 diploid individuals from three species, including 19 V. elliottii, 12 V. fuscatum, and 35 V. darrowii accessions collected throughout the species’ ranges. Results from our analyses indicated that the samples from each species could be reliably resolved using genetic distance measures with ordination and neighbor joining approaches. In addition, we estimated admixture among these species by using Bayesian assignment tests, and were able to identify a mis-labeled accession of V. darrowii ‘Johnblue’, two mis-classified accessions (CVAC 735.001 and CVAC 1223.001), and four accessions of previously undescribed hybrid origin (CVAC 734.001, CVAC 1721.001, CVAC 1741.001, and Florida 4B CVAC 1790). Allele composition at the 14 SSRs confirmed that Florida 4B CVAC 1790, the donor of low chilling for the southern highbush blueberry, was the critical parent of US 74. Genetic diversity assessment and identification of these wild accessions are crucial for optimal germplasm management and expand opportunities to utilize natural variation in breeding programs.     

Rabbiteye blueberry plant response to nitrogen and phosphorus

Acid, sandy soils selected for blueberry production are usually deficient in plant available phosphorus. Fertilizer addition at planting has not been a recommended practice. This research was designed to evaluate potted blueberry (Vaccinium ashei Reade) plant growth response to P applied at establishment and interacted with N applied during the growing season. Four liter containerized ‘Tifblue’ rabbiteye blueberry plants were transplanted into 4.4 kg of 1:1 v/v loamy sand:peat mixture in an 8‐liter container. Preplant P was incorporated into the mixture at 0, 20, 40, 60, and 80 kg/ha rates. Nitrogen was split‐applied post‐plant four times at 60‐day intervals beginning 30 days after blueberry bushes were transplanted. Total N rates were equivalent to 0, 112, 224, or 336 kg/ha. Plants were harvested 270 days after transplanting. Phosphorus at the 60 and 80 kg/ha rates increased plant growth 40 and 31%, respectively. Plant growth responded linearly to increasing N rate. Leaf and stem weight increases contributed to this linear response while root weight was not affected by fertilizer N. Total plant dry weight was increased by N rates at the 60 and 80 kg/ha P levels. Phosphorus applications increased leaf P levels, but did not increase soil test P. Leaf redness, caused by cool temperatures, was reduced by high N rates. The optimum P rate for fertilization of the soilrpeat mixture in the planting hole under conditions of this experiment was the equivalent of 60 kg/ha.     

Water Repellence of Cultivated Organic Soils

Abstract

A range of cultivated organic soils was studied with respect to water repellence. All soils were wettable above a water content of approximately 30-50 % (v/v). Below this critical content, most soils showed a varying degree of water repellence. Well decomposed peat had lower infiltration rates than moderately decomposed peat. Lightly crushing the peat soil before measurement increased the infiltration rate compared with an undisturbed soil sample. In tests with aqueous ethanol of different molarity, peat soils showed greater repellence than gyttja soils. All moss peat layers were extremely water repellent and fen peats slightly less repellent. Water repellence did not occur on gyttja clay and marl gyttja.     

Effect of manganese on endomycorrhizal sugar maple seedlings

Abstract

Manganese (Mn) toxicity may play an important role in the poor survival of seedlings in declining sugar maple (Acer saccharum Marsh.) stands in northern Pennsylvania. To determine the effect of Mn on the growth of sugar maple seedlings, 1‐year‐old seedlings inoculated with vesicular‐arbuscular mycorrhizal (VAM) fungi and growing in sand‐vermiculite‐peat moss medium were irrigated for 7 weeks with nutrient solution (pH 5) containing 0.1 (control), 1, 2, 4, 8, or 16 mg L^?1 Mn. Total seedling dry weight was negatively correlated with Mn, becoming significantly different than the control at 2 mg L^?1 Mn. Stem and root dry weight were reduced by lower Mn levels than leaf dry weight. Manganese had no effect on the root/shoot ratio. The concentration of Mn in roots and leaves increased as the level of Mn in the nutrient solution increased, with the concentration in the leaves 2.2‐ to 3.7‐fold greater than the concentration in the roots. Except for a reduction of P in the roots, Mn had little effect on the concentration of nutrient elements in the roots or leaves. Colonization of the roots by VAM fungi was increased by Mn, with a maximum percentage at 4 mg L^?1 Mn. Manganese toxicity symptoms in the leaves, small discrete chlorotic spots, began to appear at 1 mg L^?1 Mn. The sensitivity of sugar maple seedlings to Mn found in this study supports the hypothesis that Mn may affect regeneration in declining sugar maple stands. However, evaluation of the effects of Mn on seedlings in native soils under field conditions will be necessary before the role of Mn in sugar maple regeneration can be understood.     

Nutrient availability and response of sago palm (Metroxylon sago Rottb.) to controlled release N fertilizer on coastal lowland peat in the tropics

Sago palms (Metroxylon sagu Rottb.) growing on peat soils were found to grow more slowly and to show a lower production than palms growing on mineral soils. This difference was related to the physical and chemical constraints of peat soils, which include low bulk density, high acidity, and low N, P, K, Ca, Zn, and Cu levels. In coastal lowland peat soils, the distance from the sea has been found to be an important determinant of soil elemental composition. We predicted that a sufficient supply of N at the rosette stage would improve sago palm growth and that the availability of N in soil to which controlled release N fertilizer was applied might be higher than that in soil treated with soluble fertilizer. To investigate the changes in the nutrient composition of peat soils at various distances from the sea and the effect on sago palm growth, we studied sago palm areas in Indonesia and Malaysia. To observe the influence of N on the growth performance, we also conducted a fertilizer experiment on coastal lowland peat soil in Indonesia. Distance from the sea had no significant effect on the cation concentration in the soil solution (with the exception of Mg) or on the levels of soil-exchangeable cations. No significant differences were observed between the concentrations of exchangeable cations in surface peat soils and those in mature leaves. However, the concentrations of K, Na, and Ca in mature leaves increased significantly with their concentrations in the soil solution. This finding implies that the concentrations of cations in sago palm leaves depend directly on the concentrations of cations in the soil solution. No significant effect of N fertilizers on plant height and leaf formation was observed. N fertilizers applied twice a year did not affect appreciably the foliar concentration of N determined in December 1998 (5 months after the initial application) and December 1999. In June 2000, we detected a significantly higher concentration of N (p < 0.01) in young leaves of the palms treated with LP-100 or urea than in control leaves. However, no significant difference was detected between the LP-100 and urea treatments in the concentration of N in both mature and young leaves. This finding indicated that the concentration of N in sago palm leaves increased with the level of soil-applied N, regardless of whether N was applied as controlled release fertilizer or in the soluble form. We anticipate that a significant difference in the effects of these N fertilizers may occur during the next rainy season, when there should be a considerable loss of soluble N.     

Effect of Compost Properties on Progress Rate of Verticillium dahliae Attack on Eggplant (Solanum melongena L.)

Several composts were tested for their capacity to moderate the effect of Verticillium dahliae Kleb. (VCG B4, VD) on eggplant (Solanum melongena) under greenhouse conditions. Eggplants plantlets were inoculated by immersing their roots in conidial suspension and then planted in pots filled with mixtures of compost or peat moss, mixed with perlite. Six composts and peat moss mixtures were tested, of which tomato waste compost suppressed V. dahliae, and turkey litter compost partially suppressed it. Reduced levels of symptoms and lower fungal colonization were detected in the xylem of eggplants planted in tomato waste compost, and these plants accumulated more dry matter and had higher chlorophyll content compared to other media. However, survival of conidia in tomato waste compost showed only a moderate decrease compared with a sharp decrease in other media, suggesting that conidial eradication cannot be proposed as the suppressiveness mechanism. γ irradiation of tomato waste compost and peat at 2.5 Mrad reduced microorganism density by four orders of magnitude, but irradiation of tomato waste compost did not reduce its suppressiveness of V. dahliae. Composts properties affected progress rate of VD in the xylem tissue of eggplant seedling. These properties could indicate both biotic and abiotic factors affecting the process.     

Fertilization of rabbiteye blueberries grown on a typic paleudult soil

A 6 year field study comparing the effects of 5 fertilizer sources applied at 4 levels to 3 rabbiteye blueberry (Vaccinium ashei Reade) cultivars was established on a Typic paleudult soil in southern Misssssippi. Fertilizer sources had little influence on plant height, vigor, chlorosis, or fruit yield. The first year, ‘Tifblue’ was lowest in vigor and fruit yield, but after 4 growing seasons, had the highest plant height and fruit yields. Chlorosis symptoms were more prevalent at the highest fertilization rate, in the cultivar ‘Woodard’, and with Ca(NO₃)₂ fertilizer. During the first 5 years, fruit yields increased as fertilization levels increased from 0 to 5.9 g N/plant but additional fertilization did not influence yields There were no differences in plant vigor due to cultivars but the highest rate of fertilization decreased vigor. The cultivar X fertilization rate interaction was significant for plant height in 1983 and for fruit yields in 1984 and 1985. ‘Delite’ and ‘Woodard’ plant height increased while height of ‘Tifblue’ decreased as fertilization rates increased from the 0 to 5.9 g N/plant levels; higher rates decreased plant height in all cultivars. In 1984 and 1985 fruit yields of ‘Woodard’ and ‘Delite’ were not influenced by fertilization but yields of ‘Tifblue’ indicated a negative response to increasing fertilizer levels.     

Effect of peat moss‐shrimp wastes compost on the growth of barley (Hordeum vulgare L.) on a loamy sand soil

Abstract

A greenhouse experiment was conducted to determine the effect of peat moss‐shrimp wastes compost on barley (Hordeum vulgare L.) grown on a limed loamy sand soil. A control, four rates of compost applied alone and in combination with three rates of nitrogen, phosphorus, and potassium (NPK) chemical fertilizer were evaluated. Applications of compost to limed soil substantially enhanced the growth of barley over the control. When considering all treatments, the main effect of compost rates on straw yield, numbers of tillers, plant height, and number of ears was more important than that of fertilizer. A significant interaction on barley growth parameter values was obtained with compost and fertilizer rates. A combination of moderate application of compost and fertilizer gave in some instances, more yield than compost or fertilizer applied alone. Nutrient content of barley increased with rate of compost applied to soil over the control. A significant relationship was found between soil organic carbon (C) and straw yield, number of tillers, plant height and number of ears whereas grain yield was correlated with soil total N. Results from this study indicate that peat moss‐shrimp wastes compost could represent a potential means of renovating low fertility sand soils.