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1.
This research was conducted to determine the effectiveness of various treatments in correction of single deficiency of iron (Fe) and multiple deficiencies of Fe, zinc (Zn), and boron (B) in an olive cultivar (Gemlik) in the southeastern Marmara region of Turkey. This study was consisted of four field experiments, which included control, soil and foliar applications of Fe alone, and combinations with Zn and B. Soil applications of the compounds were only performed in the first year of the experiments to estimate residual effect of soil applications in the following year. Foliar applications were sprayed onto leaves two and four times at two doses in consecutive years. Soil application of iron sulfate did not increase Fe concentrations in the both leaves and fruits. Foliar applications of iron sulfate considerably elevated leaf total and active Fe concentrations, but the effect of the foliar applications on fruit Fe concentrations was small. Two foliar applications of iron in each season seemed to be appropriate treatment in the all experiments, as well. To maintain sufficient Fe concentrations, especially in the newly developing tissues of olive trees, foliar application of Fe should be conducted at least four times at the lowest dose as performed in the experiments. Foliar applications of double and triple combinations of iron sulfate with zinc sulfate and borax increased significantly B and Zn concentrations in the trees, as well.  相似文献   

2.
This experiment was conducted at Zahak Agricultural Research Station in the Sistan region in southeast Iran. A factorial design with three replications was used to determine the effects of zinc (Zn), iron (Fe), and manganese (Mn) applications on wheat yield, Zn, Fe, and Mn uptakes and concentrations in grains. Four levels of Zn [soil applications of 0, 40, and 80 kg ha?1 and foliar application of 0.5% zinc sulfate (ZnSO4) solution], two levels of iron sulfate (FeSO4; 0 and 1%) as foliar application, and two levels of Mn (0 and 0.5%) also as foliar application were used in this study. Results showed that the interactive effects of Zn and Mn were significant on the number of grains in each spike. The highest number of grains resulted from the application of 80 kg ZnSO4 ha?1 and foliar Mn. The interactive effects of Zn and Fe were significant on weight of 1000 grains. The highest weight of 1000 grains resulted from application of 80 kg Zn and foliar Fe. Application of 80 kg ZnSO4 ha?1 alone and 80 kg ZnSO4 ha?1 with foliar application of Mn significantly increased grain yield in 2003. The 2‐year results showed that foliar application of Zn increased Zn concentration and Fe concentration in grains 99% and 8%, respectively. Foliar application of Fe resulted in a 21% increase in Fe concentration and a 13% increase in Zn concentration in grains. The foliar application of Mn resulted in a 7% increased in Mn concentration in grains.  相似文献   

3.
To increase iron (Fe) concentration in edible portions of staple food crops, an agronomic approach via foliar Fe-containing solutions might be sustainable and economical strategy; however, little information is available in the literature. So the present work was carried out to examine the effects of Fe in association with boron (B) foliar fertilization on Fe biofortification and the nutritional quality of rice (Oryza sativa L.) grain. The work was conducted in 2006 at the research experiment station at Zhejiang University on japonica rice ‘Bing 98110’ planted on a silty loam soil in pots. The following spray treatments were performed at rice anthesis: (1) control (the deionized water spray); (2) 0.1% (w/v) FeSO4 · 7H2O; (3) 0.1% (w/v) Fe(II)-AA (Complex of 0.1% FeSO4 · 7H2O and 0.4% compound amino acids; 18.6% N); (4) 0.2% (w/v) H3BO3 (boric acid, 17.5% B); (5) combined spray of 0.1% (w/v) FeSO4 · 7H2O and 0.2% (w/v) H3BO3; (6) combined spray of 0.1% (w/v) Fe(II)-AA and 0.2% (w/v) H3BO3. Foliar Fe and B complex application did biofortify Fe concentration and other measured nutritive values in polished rice. Compared to the control, Fe concentration in seed increased significantly 18.9% with the combination of foliar Fe(II)-AA and B, Zn content increased significantly 26.7%, and protein and total 16 amino acids, such as lysine, threonine, and arginine that were essential for human nutrition as well as glutamic acid, aspartic acid, valine, leucine, and phenylalanine, etc., also increased markedly by 30.9% and by 37.0%, respectively.  相似文献   

4.
Boron (B) deficiency frequently occurs on soils that are low in organic carbon (C) (<1.0% organic C), pH (soil pHCa <5.0), and clay content (<5% clay). Acid sands with these soil properties are common in south-western Australia (SWA). Moreover, hot calcium chloride (CaCl2) extractable B levels are commonly marginal in the acid sands of SWA. This study examined the effects of soluble and slow release soil-applied B fertilizer and foliar B sprays on crops most likely to respond to B fertilizer on these soils, canola (oil-seed rape, Brassica napus L.) and lupin (Lupinus angustifolius L.).

At 25 sites over three years, canola was grown with (0.34 kg ha-1) or without B applied as borax [sodium tetraborate decahydrate (Na2B4O7·10H2O) 11% B], and this was followed by nine experiments with B rates [0, 0.55, 1.1 kg ha?1, applied as borax or calcium borate (ulexite, NaCaB5O6(OH)6·5(H2O), 13% B] and foliar sprays (0.1% solution of solubor, 23% B) in 2000–2001. A further five sites of B rates and sources experiments were carried out with lupin in 2000–2001. Finally, foliar B sprays (5% B w/v as a phenolic complex) at flowering were tested on seven sites in farmers’ canola crops for seed yield increases. No seed yield increases to soil-applied B were found while foliar B application at flowering increased canola seed yield in only one season across seven locations. By contrast, borax fertilizer drilled with the seed at sowing decreased canola seed yield in nine of 34-farm sites, and decreased lupin yield in two of five trials. Toxicity from drilled boron fertilizer decreased yield could be explained by decreases in plant density (by 22–40%) to values lower than required for optimum seed yield. Seedling emergence was decreased by borax applied at sowing but less so by calcium borate. Foliar B spray application never reduced seed yield due to toxicity effects.

Boron fertilizer drilled with the seed increased the B concentration in plant dry matter at early to mid-flowering. Boron application decreased the oil concentration of grain of canola at four sites. The oil yield of canola was significantly decreased at seven sites.

Notwithstanding the marginal B levels on acid sands of the SWA region, care needs to be taken on use of borax fertilizer as toxicity was induced in canola and lupin; with 0.34 to 1 kg B ha?1(3-10 kg borax ha?1) at sowing depressing seed yield, mostly by decreasing plant density. Rather than making general recommendation for B fertilizer application based on 0.01M CaCl2 soil extractable B, soil and plant analysis should be used to diagnose B deficiency and B fertilizer use limited to calcium borate or foliar borax rather than soil-applied borax on low B sands.  相似文献   

5.
This study was implemented to determine effectiveness of various treatments in recovering boron (B)–deficient olive trees in the Marmara region. The study was carried out during the period 2000–2005. The experimental soil was in loamy texture with medium alkaline pH, low organic matter, and low B concentration. The experiment was conducted in a randomized plot experimental design with 12 treatments. In the study, different B fertilizers were applied to soil and leaves. Treatments of 125, 250, and 500 g?1 borax (sodium tetraborate) were applied to the soils at the beginning of the experiment to determine the later effects of sodium tetraborate. Treatments of 125, 250, and 500 g borax were applied to the soils every year in March. Also, 0.4% borax was applied two or three times, 0.8% sodium tetraborate two or three times, and 0.5% bor-track (boron ethanol amine) two times by foliar applications during the growing period. According to the results, two applications of 0.4% sodium tetraborate to the leaves gave the best results. Soil applications of 250 g sodium tetraborate every year and 500 g sodium tetraborate every two years were the most effective treatments.  相似文献   

6.
ABSTRACT

Iron (Fe) deficiency is one of the serious nutritional disorders in aerobically grown rice on upland alkaline and calcareous soils, which leads to a decline in productivity. With a view to resolve the Fe-deficiency syndrome in aerobic rice, the influence of soil moisture regimes, farmyard manure (FYM) and applied Fe on the release of Fe was assessed under an incubation study. A field experiment was also conducted to evaluate the relative effectiveness of soil and foliar applications of Fe in alleviating Fe deficiency using four rice cultivars (‘IR 36’, ‘IR 64’, ‘IR 71525-19-1-1’ and ‘CT 6510-24-1-2’). Results of incubation study indicated that the application of FYM marginally improved the diethylene triamine pentaacetic acid (DTPA)-Fe status of soil over control. However, application of iron sulfate (FeSO4 · 7H2O) at 14 mg Fe/kg with FYM released as much Fe as did the application of 27 mg Fe/kg as FeSO4 7H2O alone. Comparatively higher amounts of Fe were released under water saturation than that under drier soil moisture regimes and the effect of incubation period in releasing Fe was pronounced only under water saturation.

Under field study, supplementation of Fe through integrated or inorganic source caused improvement in the DTPA and ammonium acetate (NH4OAc) extractable Fe similar to that recorded under incubation. The foliar application of Fe (3% FeSO4 7H2O solution, thrice at 40, 60, and 75 days after sowing of rice, i.e., 45 kg FeSO4.7H2O/ha) was most effective and economical in correcting Fe deficiency in aerobic rice, followed by soil application of 150 kg FeSO4.7H2O + 10 t FYM/ ha and 305 kg FeSO4.7H2O/ha. Among the rice cultivars, ‘CT 6510-24-1-2’ and ‘IR 71525-19-1-1’ performed better under aerobic condition compared to ‘IR 36’ and ‘IR 64’. Differential response of rice cultivars to applied Fe was not related to Fe-nutrition; rather it was apparently related with inherent ability of cultivars to grow under water-stress condition. Ferrous iron (FeII) content in rice plants proved to be a better index of Fe-nutrition status compared to total plant Fe and chemically extractable soil Fe. The FeII concentration of ≥ 37 mg kg?1 in plants (on dry weight basis) appeared to be an adequate level at 60 days after sowing for direct seeded rice grown under upland aerobic condition.  相似文献   

7.
ABSTRACT

The effectiveness of nitrogen (N)+ zinc (Zn) soil and foliar fertilizer applications on growth, yield, and quality of apple (Malus domestic Borkh ‘Golden Delicious’) fruit was studied in the Zanjan province, Iran. There were eight treatments 1) control (no fertilizer), 2) soil applied N, 3) soil applied Zn, 4) soil applied N+Zn, 5) foliar applied N, 6) foliar applied Zn, 7) foliar applied N+Zn and 8) combined soil and foliar applied N+Zn. The N source was urea [CO(NH2)2, 46% N] applied at 276 N tree? 1 yr?1 and the Zn source was zinc sulfate (ZnSO4,7H20, 23% Zn) applied at 110 g Zn tree? 1 yr? 1. The soil treatments of N and Zn, were applied every two weeks during June through August (total of 6 times/year) in a 1 m radius around the tree trunk (drip line of trees). The foliar solutions of N (10 g l? 1 urea) and Zn [8 g l? 1 zinc sulfate (ZnSO4)] were sprayed at the rate of 10 L tree? 1 every two weeks at the same times as described for soil applications. The highest yield (49 kg tree? 1), and the heaviest fruits (202 g) were obtained in the soil and foliar combination of N+Zn treatment. The lowest yield (35 kg tree? 1), and the smallest fruits (175 g) were recorded in the control. Nitrogen, and to a lesser extent Zn, foliar application resulted in decreasing fruit quality (caused russeting, and lower soluble solid), but increasing N leaf and fruit concentrations (2.4% DW and 563 mg kg? 1, respectively). There were significant differences among yield and leaf mineral nutrient concentration in different treatments. But there was no significant difference between fruit mineral nutrient concentration (except N). Ratio of N/calcium (Ca), potassium (K)/Ca, and [magnesium (Mg)+K]/Ca in fruits were found suitable for fruit quality prediction. Combining the zinc sulfate with urea in the foliar applications increased the concentration of Zn from 0.7 to 1.5 mg per kg of apple tissue. Leaf N concentration varied during growth season. Foliar applied nutrient can be more efficient than soil applied, but a combination of soil and foliar applications is recommended for apple tree nutrient management.  相似文献   

8.
ABSTRACT

Three field experiments at three sites in east Zhejiang Province were conducted to determine the influence of applications of boron (B) on growth, yield, and quality of the red bayberry trees (Myrica rubra Sieb. et Zuca) with a manure species of “Buqizhong” in Linhai city. Ground B application or foliar B spraying significantly improved length and incidence rates of spring and summer shoots and increased fruit set rates, which resulted in the increases in fruit yield (13.7–17.5% for ground B application or 13.2–27.3% for foliar B spraying) and in improvement of fruit quality. The optimum yields were recorded with the treatments of ground B application of 40 g tree?1 of borax or foliar B spraying of 2.0 g L?1 of borax. Spring shoot incidents for the treatment of ground application of 50 g borax tree?1 every year during the experiment (4B50) were significantly higher than that for the treatment of ground application of 50 g borax tree?1 only in the first year of the experiment (B50), but the yield difference between them was not significant at P = 0.05. The increased yield effect of ground B application could last for 3 years. Boron application of red bayberry trees can be carried out by foliar-spraying 2.0 g borax L?1 every year or ground application of 50 g borax tree?1 every 3 years. The results of this study showed that application B could significantly improve the growth and increased fruit yield and quality of the red bayberry trees not exhibiting any vegetative symptoms of B deficiency.  相似文献   

9.
Poor zinc (Zn) nutrition of wheat is one of the main causes of poor human health in developing countries. A field experiment with no zinc and foliar zinc application (0.5% ZnSO4.7H2O) on bread wheat (8), durum wheat (3), and triticale (4) cultivars was conducted in a randomized block design with three replications in 2 years. The experimental soil texture was loamy sand with slightly alkalinity. The grain yields of bread wheat, triticale, and durum wheat cultivars increased from 43.6 to 56.4, 46.5 to 51.6, and 49.4 to 53.5 t ha?1, respectively, with foliar application of 0.5% ZnSO4.7H2O. The highest grain yield was recorded by PBW 550 (wheat), TL 2942 (triticale), and PDW 291 (durum), which was 5.22, 4.24, and 4.56% and significantly higher over no zinc. Foliar zinc application increased zinc in bread wheat, triticale, and durum wheat cultivars grains varying from 31.0 to 63.0, 29.3 to 61.8, and 30.2 to 62.4?mg kg?1, respectively. So, agronomic biofortification is the best way which enriching the wheat grains with zinc for human consumption.  相似文献   

10.
Boron (B) is a micronutrient essential for adequate plant growth. Borax (Na2B4O7·10H2O) and colemanite (Ca2B6O11·5H2O) are common B fertilizer materials, the former being widely used worldwide. Boron is completely water soluble and subjected to leaching. In this study, the dissolution kinetics of both borax and colemanite in deionized water and at pH 3.8, 5.2, 6.5, and 8.2 were determined. Soils incubated with minerals for 40 days and 80 pore volumes of leachates from repacked soil column treated with either surface-applied borax or colemanite (powdered and granular) were collected and analyzed for B contents. Two different soils, Chempaka (Typic paleudult) and Tepus (Typic Kandiaquult) series, taken from paddy-growing areas were used in leaching and incubation studies. Dissolution rate of borax was greater than that of colemanite, and complete dissolution was observed after 100 min, whereas complete dissolution of colemanite was not reached even after 300 min. There was no effect of pH on dissolution rate of borax and colemanite. Boron released from borax was hasty, and after 5 weeks no more B was released. In the case of colemanite, B released was steadily increased until the end of the incubation study. At the end of the study, there was no significant difference in B levels of both borax- and colemanite-applied soils. Particle size had a significant effect on the solubility and dissolution rate of colemanite. Boron dissolution rate and solubility from colemanite powder were significantly greater than those from granular colemanite. Leaching losses from borax were much greater than from colemanite as indicated by the breakthrough curves, which were earlier for borax than colemanite. After 60 pore volumes, no more B was leached out from borax, and in the leachates of colemanite some concentration was detected even after 80 pore volumes. Boron content in soil of columns after the completion of the experiment was greater in case of colemanite. Borax and colemanite fertilizers showed the same trend of leaching and B releasing in both Tepus and Chempaka soil series.  相似文献   

11.
Rice is very sensitive to low zinc(Zn) supply in submerged paddy soils and Zn deficiency is one of the major limiting factors in determining rice production in India. A field experiment was conducted during the summer-rainy seasons of 2009 and 2010 at the research farm of the Indian Agricultural Research Institute, New Delhi, to determine the effects of summer green manure crops and Zn fertilizers on diethylenetriaminepentaacetic acid(DTPA)-extractable(available) Zn concentration in soil and total Zn content in Basmati rice cultivar Pusa Basmati 1 at periodic intervals. Summer green manure crops included Sesbania aculeata(Dhaincha),Crotalaria juncea(Sunhemp), and Vigna unguiculata(Cowpea) and the Zn fertilizers used were ethylenediaminetetraacetic acid(EDTA)-chelated Zn, ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnO, and ZnSO_4·7H_2O + ZnO. Beneficial effects of summer green manure crops and Zn fertilizers on DTPA-extractable Zn concentration in soil and total Zn content in dry matter of Basmati rice at periodic intervals were observed, with significant increases in all the determined parameters, in comparison with those in the control(no Zn application or summer fallow). The rate of increase varied among summer green manure crops and Zn fertilizers during both years. Among the summer green manures, incorporation of S. aculeata led to a significant increase in mean Zn content in Basmati rice grain and straw when compared with C. juncea, V. unguiculata, and summer fallow treatments. Among the Zn fertilizers, significant increases in Zn content in Basmati rice dry matter and DTPA-extractable Zn concentration in soil during various growth stages of the plant were recorded with EDTA-chelated Zn application, followed by the application of ZnSO_4·7H_2O, ZnSO_4·H_2O, ZnSO_4·7H_2O + ZnO, ZnO,and no Zn. The highest mean Zn content in Basmati rice grain and straw was recorded with EDTA-chelated Zn application in 2009 and 2010, respectively. The application of ZnSO_4·7H_2O was the second best treatment after EDTA-chelated Zn; however, it was statistically inferior to EDTA-chelated Zn. The lowest values were recorded with the control(no Zn application) during both years of study. The amount of Zn concentration in soil was found to be significantly positively correlated with the Zn content in Basmati rice dry matter during both years. Significantly higher levels of residual fertility in soil after the harvest of Basmati rice were observed with application of EDTA-chelated Zn and incorporation of S. aculeata when compared with those of other Zn sources and summer green manures.  相似文献   

12.
Seedlings of sour orange (Citrus aurantium L.) and Carrizo citrange (C. sinensis L. cv. Washington navel x Poncirus trifoliata)] were grown in plastic pots containing a sand: perlite mixture and watered with a modified Hoagland No 2 nutrient solution throughout the experiment. Three-months-old plants were divided in three groups and sprayed with 0.018 M iron sulfate (FeSO4 .7H2O), 0.018 M manganese sulfate (MnSO4 .H2O), or deionized water. Two months later, plants were harvested and divided into top leaves that grown after the treatments, basal leaves that existed prior to the treatments, stems that partially came in contact with the spray, and roots. The manganese (Mn) spray resulted in a significant increase of Mn concentrations in top leaves, basal leaves, stems and roots of sour orange, and in top leaves, basal leaves, and stems of Carrizo citrange. The iron (Fe) spray significantly increased the concentrations of Fe in the stems and basal leaves of both genotypes. For both genotypes, transport of Mn from basal (sprayed) leaves to top (unsprayed) ones was found. However, the results of this experiment did not give any evidence neither for Mn translocation from sprayed tissues to roots nor for Fe transport from sprayed tissues to unsprayed ones (top leaves, roots). Mn and Fe were found to be relatively mobile and strictly immobile nutrients, respectively, within citrus plants after their foliar application as sulfate salts.  相似文献   

13.
To study the response of date palm trees to Fe fertilization, two date palm cultivars, Khlas and Ruzaiz, were fertilized with different levels of FeEDDHA (trunk injected and through soil) and FeSO4 · 7H2O(trunk injected). Leaves were collected 100 days after iron application and analyzed for micronutrients. The injection with 100 g FeSO4 · 7H2O/tree increased the Fe contents in the leaves of both cultivars, and with 100 g FeEDDHA/tree in the leaves of Ruzaiz cultivar. Soil application of FeEDDHA was not effective. The contents of Cu, Mn and Zn in the leaves were not affected by Fe fertilization.  相似文献   

14.
Abstract

A field experiment was conducted during 1989–91 to investigate and resolve iron (Fe) chlorosis that appears in the summer season in Java citronella (Cymbopogon winterianus Jowitt). The experiment consisted of nitrogen (N) levels of 0, 200, and 400 kg N/ha/year as main plots and foliar applications of ferrous sulfate (FeSO4‐7H2O) (nil and spray once in two months) as subplots in a split‐plot design. A foliar application of a 3% FeSO4‐7H2O solution once in two months resulted in the disappearance of the Fe‐deficiency symptoms, increased the leaf chlorophyll content, and the total and ferrous‐Fe contents in the leaf tissue. At the 400 kg N/ha/year treatment level, the foliar Fe spray increased significantly herb and oil yields. Thus, under intensive cultivation of Java citronella, a foliar application of Fe will avoid economic losses of essential oil yields when Fe‐deficiency symptoms appear.  相似文献   

15.
Effects of foliar applications of some micro- and macro-nutrients on mineral nutrient content of tomato leaves and fruits were investigated in an aquaponic system in comparison with a hydroponic system. Fourteen days old tomatoes seedlings were transplanted on to growth bed of aquaponic and hydroponic systems. Foliar nutrients application began 30 days after transplantation. Eight treatments were used, untreated control and foliar application at the rate of 250 mL plant?1 with 0.5 g L?1 potassium sulfate (K2SO4), magnesium sulfate (MgSO4 7H2O), ferrous (Fe)- ethylenediamine-N,N′-bis (EDDHA), manganese sulfate (MnSO4 H2O), boric acid (H3BO3), zinc chloride (ZnCl2), and copper sulfate (CuSO4 5H2O). Foliar application of potassium (K), magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) increased their corresponding concentrations in the leaves of aquaponic-treated plants. On the other hand, foliar spray of K, Fe, Mn, Zn, and Cu caused a significant increment of applied element concentrations in the fruits of hydroponic-grown plants. These findings indicated that foliar application of some elements can effectively alleviate nutrient deficiencies in the leaves of tomatoes grown on aquaponics.  相似文献   

16.
ABSTRACT

Two field experiments (2000–2001 and 2001–2002) were conducted at two nearby fields in the Qanavat region of Qom province, central Iran, to investigate the effects of zinc (Zn) fertilization on production of sunflower. The experiment was conducted in a randomized complete block design with six treatments in three replicates. Treatments were: Zn0 (non-Zn fertilized), Zn10, Zn20, Zn30, and Zn60 (soil application of 10, 20, 30, and 60 kg Zn ha?1, respectively), and ZnSpray (foliar spraying of 0.5 kg Zn ha?1 using ZnSO4). Seeds of sunflower (Helianthus annuus cv. ‘Record’) were planted on June 20, 2000 and June 15, 2001. At harvest, shoot and seed yields as well as concentration of Zn, iron (Fe), manganese (Mn), sodium (Na), and chloride (Cl) in leaves of sunflower were determined. Addition of 20 kg Zn ha?1 significantly increased seed production and shoot dry-matter yield of sunflower, while other Zn treatments had no significant effect on shoot dry-matter yield, or decreased it. The thousand-seed weight was the yield component most affected by Zn fertilization, while plant height and head diameter did not change. The maximum content of seed oil was achieved under the Zn10 treatment, then decreased at higher rates of soil-applied Zn such that oil content of seed under the Zn30 and Zn60, treatments was significantly lower than that of the control. Seed oil content was unaffected by foliar spraying of Zn. The concentration of Zn in sunflower leaves was increased with an increase in soil-added Zn of from 0 to 60 kg Zn ha?1. The highest leaf concentrations of Zn (162 and 175 mg kg?1 day matter (DM) in the first and second year, respectively) were achieved by foliar application of ZnSO4. Leaf concentration of Fe was significantly increased in the Zn20 treatment compared with the control but decreased at the higher rates of soil-added ZnSO4. Soil addition of different levels of ZnSO4 decreased concentration of Na and Cl in leaves. The lowest concentration of Na and Cl in leaves was observed under Zn20. The results of this study suggest that soil application of a suitable amount of Zn has a positive effect on both quantitative and qualitative yield of sunflower in saline, calcareous soils.  相似文献   

17.
Four separate experiments were carried out in greenhouse conditions from spring of 2001 to summer of 2003. The aim of this research was to study the effect of factors such as leaf age, salt type and concentration, number of foliar applications, and the nutritional status on the efficiency of foliar applications of potassium (K) in olive plants. In all experiments, mist-rooted ‘Picual’ olive plants growing in 2 L pots containing perlite were fertigated with a complete nutrient solution containing 0.05 mM or 2.5 mM potassium chloride (KCl). In one experiment, plants received two foliar applications with five concentrations of KCl (0%, 2%, 4%, 6%, or 8%) at 63 and 84 days after transplanting. Foliar KCl applications at 2% or 4% increased shoot lengths and the K content of plants fertigated with 0.05 mM KCl (poor K nourished), while foliar KCl application did not have any influence on the growth or K content of plants fertigated with 2.5 mM KCl (normal K nourished). When the number of foliar applications was increased, the results showed that two foliar applications were enough to increase leaf K concentration in olive plants above the sufficiency level. Leaf age could influence the efficiency of foliar K application. Leaf K concentration were higher in young leaves than in mature ones. All K-salts studied as foliar sprays [KCl, potassium sulfate (K2SO4), potassium nitrate (KNO3), potassium carbonate (K2CO3), and potassium phosphate (KH2PO4)] were effective in increasing leaf K concentration. The results obtained in the present study indicate that foliar applications of K effectively increase K content in K-deficient olive plants, and that foliar applications might be more effective on young leaves. Two foliar applications of 4% KCl or the equivalent for other salts are enough to increase leaf K concentration.  相似文献   

18.
Abstract

Experiments were conducted to examine whether the foliar application of zinc (Zn) could mitigate the adverse effects of heat stress on pakchoi plants. Two varieties of pakchoi (Aikangqing and Wuyueman) were foliar applied with ZnSO4·7H2O (0%, 0.02%, 0.05%, 0.10%, 0.20%, 0.40%, 0.60%, and 0.80%), and then subjected to two temperature levels (22°C/16°C, day/night; 40°C/30°C, day/night). Heat stress decreased the net photosynthetic rate (Pn) (50.65% and 62.14% for Aikangqing and Wuyueman, respectively), chlorophyll content, chlorophyll fluorescence ratio (Fv/Fm), and effective quantum yield of PSII photochemistry (ΦPSII) of the leaves. Foliar application of ZnSO4·7H2O (0.02%–0.40%) effectively alleviated the heat stress in pakchoi by enhancing shoot Zn concentration, superoxide dismutase (SOD) activity, chlorophyll content, Fv/Fm, and ΦPSII. Pn increased by 12.61%–46.19% and 45.73%–119.01% in Aikangqing and Wuyueman compared with those without Zn treatments, respectively. Fuzzy comprehensive evaluation and the extreme model showed that Aikangqing and Wuyueman treated with 0.1218%–0.1220% ZnSO4·7H2O (approximately 0.004?M Zn2+) and 0.2178%–0.2744% ZnSO4·7H2O (approximately 0.008?M Zn2+) exhibited the most heat resistance, respectively. Furthermore, Zn (0.02%–0.80% ZnSO4·7H2O) application had no significant effect on most physicochemical parameters under normal temperature, which only increased shoot Zn and SOD. The results suggest that additional Zn would be required to fully protect plant growth from heat stress. Foliar application enhanced Zn concentration in leaves, thereby maintaining the SOD activity and membrane stability and protecting photosynthesis against heat damage.  相似文献   

19.
【目的】施用锌肥是改善作物缺锌、 提高产量和籽粒锌含量的重要措施。锌肥的施用效果受多种因素的影响,通过总结自70年代以来锌肥施用对我国主要粮食作物小麦、 玉米、 水稻产量的影响,分析不同年代、 锌肥施用方式、 锌肥用量对这三大作物产量影响的进程,探讨锌肥的适宜用量和施用方式。【方法】利用万方数据库、 中国知网,查阅了1970至2013年间,我国主要粮食作物水稻、 小麦和玉米锌肥施用相关的田间试验文献333篇,剔除文献中没有产量数据、 没有具体施肥相关信息如施肥量、 施肥方式等文献,有效样本数总计为1656个。采用相关分析、 方差分析等统计分析方法,Microsoft Excel 2010软件分析。【结果】锌肥增产效果受锌肥施用方式、 施用量、 年代的影响,具体结果如下, 1)锌肥施用方式土壤施用、 叶面喷施和种子处理在小麦上的平均增产率分别为11.3%、 10.0%和11.1%; 在玉米上的平均增产率分别为13.7%、 12.7%和12.1%; 水稻上的平均增产率分别为15.0%、 9.8%和9.7%。与叶面喷施和种子处理相比,无论是小麦、 玉米还是水稻,土施锌肥的增产效果最好。2)锌肥施用量小麦、 玉米和水稻的增产率随土施锌肥量增加而增加,当施锌量达到一定量后,随施肥用量的进一步增大,增产率有所降低。小麦、 玉米和水稻土施锌肥的合适用量分别为1545 kg /hm2、 2030 kg/hm2、 2030 kg/hm2。小麦增产率与喷施锌肥的浓度关系不明显,叶面喷施浓度在0.4%~0.5% ZnSO47H2O时增产效果最佳; 而玉米、 水稻增产率和叶面喷施锌肥的浓度变化趋势与土施锌肥变化趋势一致。过去40年玉米和水稻适宜喷施锌肥浓度分别是0.1%~0.3%、 0.2%~0.4% ZnSO47H2O。3)施肥年代随着年代的变化,不同作物施用锌肥的增产幅度不同。随着年代的推进,同一锌肥施用方式在小麦上增产率呈逐渐增高的趋势; 锌肥土施和叶面喷施在玉米上的增产率呈下降趋势; 锌肥土施在水稻上的增产率呈下降趋势,而叶面喷施在水稻的增产率呈先降低后增加的趋势; 种子处理方式在水稻和玉米上的增产率随年代的变化不明显。【结论】施用锌肥能有效提高小麦、 玉米和水稻的产量,但是其增产效果受锌肥施用方式、 施用量、 年代的影响。因此,今后在锌肥施用方面,农户应根据作物、 土壤、 环境等条件,选择恰当的施肥方式及锌肥用量,来提高锌肥的增产效果。  相似文献   

20.
ABSTRACT

A field trial was conducted at Rajasthan Agricultural University, Bikaner, India, in the summers of 2002 and 2003 to determine the effect of sulfur (S) in improving iron (Fe) nutrition of mungbean (Vigna radiata L.) grown on calcareous soils. The experiment was laid out in a split-plot design with three replications. Four levels of sulfur (0, 20, 40, and 60 kg S ha?1) were applied in main plots. In sub-plots, eight levels of Fe were replicated. Three levels of Fe were applied as a basal application of FeSO4 (0, 12.5, and 25.0 kg FeSO4 ha?1) and the remaining five were applied as a foliar application of 0.5% FeSO4 at branching, flowering, and at both branching and flowering with or without 0.1% citric acid. The results of the experiment revealed that application of sulfur at the higher doses had a significant positive effect on activities of catalase, ascorbate peroxidase, guaiacol peroxidase, synthesis of chlorophyll, and active Fe content of green leaves compared with lower doses. Application of 0.5% FeSO4 and 0.1% citric acid at both branching and flowering had no effect. The best results were recorded with basal application of 25.0 kg FeSO4 in combination with 40 kg S ha?1. The frequency of foliar application had an appreciable effect on chlorophyll synthesis, enzymatic activities, and active Fe content in green leaves. Plants that received foliar application of 0.5% FeSO4 + 0.1% citric acid at both branching and flowering responded more than those that received treatment at either branching or flowering. For best results, it is suggested to use 25.0 kg FeSO4 ha?1 in a basal application along with 40 kg S ha?1, as plants require most of their S and Fe at the early growth stages.  相似文献   

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