AMELIORATION OF ZINC DEFICIENCY OF CORN IN CALCAREOUS SOILS OF THAILAND: ZINC SOURCES AND APPLICATION METHODS

A variety of zinc (Zn) fertilizer sources are applied with varied responses on calcareous soils in Thailand. Seed treatment is an alternative method to deliver Zn to corn and alleviate Zn deficiency. To address this Zn delivery methods we conducted greenhouse studies on corn grown in three calcareous soils of Thailand to three Zn fertilizer sources [zinc sulfate (ZnSO₄), Zn-ethylenediaminetetraacetic acid (EDTA) and Zn citrate]. We also evaluated effectiveness of soaking corn seed in three concentrations of ZnSO₄ (0.4, 0.8 and 1.6%) prior to planting compared to soil applied methods. Applications of zinc increased the growth, dry matter yield and zinc uptake of corn with few differences observed among the types of fertilizers. Seed soaking with ZnSO₄ solution also increased Zn uptake, growth rate and yield comparable to soil-applied Zn. Seed soaking prior to planting is an effective and efficient method to supply Zn to corn grown in Zn deficient calcareous soils of Thailand.     

DISTRIBUTION AND PHYTOAVAILABILITY PREDICTION OF ZINC IN AGRICULTURAL CALCAREOUS SOILS

The extractability and distributions of zinc (Zn) were evaluated in calcareous agricultural soils from South-West Iran. Both single [diethylenetriaminepentaacetic acid (DTPA)] and sequential extraction procedures (Singh scheme) were applied to 20 representative soils. The DTPA extractable zinc levels were low (on average 3.34%). The sequential extraction procedures were also utilized for the study of zinc phytoavailability in maize plants (Zea mays L.) in a greenhouse experiment. The Singh scheme was significantly better than DTPA plus soil properties in phytoavailability prediction of zinc in soils. Significant correlations were found between the amounts of DTPA extractable zinc and the iron (Fe) oxides-bound (AFe and CFe) and residual fractions extracted by the Singh procedure. Zinc concentrations in plant samples (mean value of 27.49 mg kg^?1) were poorly correlated with the different extracted soil fractions (single and sequential). The Singh procedure provided better predictions of zinc uptake by plants than DTPA extraction method.     

DIFFERENTIAL TOLERANCE TO ZINC DEFICIENCY IN COFFEE-PLANT PROGENIES

The tolerance of different coffee-plant progenies to zinc (Zn) deficiency was studied in a green house experiment arranged in a completely randomized design, in a 14 × 2 factorial scheme (14 progenies and two Zn concentrations), with four replications. Coffee-plant seedlings were grown for ten months in nutritive solution with or without Zn. There were evaluated for growth characteristics, zinc concentrations, and zinc requirement. The grouping involving growth characteristics allowed discriminating the progeny ‘UFV 4066-3’ as highly zinc-demanding and ‘IAC 4376-5’ as low zinc-demanding. The data on plant dry matter and zinc accumulation showed that the progenies ‘IAC 4376-5’ and ‘UFV 4066-5’ had low zinc requirement when ‘Caturra Amarelo 1’, ‘UFV 4066-3’, ‘Caturra Amarelo 2’ and ‘Caturra Vermelho 2’ had high zinc requirement. Leaf area reduction (%), leaf number, active zinc content in completely expanded leaves and total zinc in roots were the variables of highest relative importance in discriminating coffee plant progenies.     

氯化胆碱对玉米光合性能的促进效应

研究了喷施不同浓度(0,200,300,500和1000ppm)氯化胆碱(CC)对玉米(Zeamays L.cv.Yu Dan 358)光合性能之影响。经200,300或500ppmCC 处理的玉米叶内叶绿素含量增加,光合速率明显高于对照.作为 C_4植物光合作用的关键酶即 PEP 羧化酶、苹果酸酶等活性明显提高,离体叶绿体的人工电子传递链活性亦被促进,离体条件下的乙醇酸氧化酶活性显著降低,叶绿体基粒片层的发育被明显促进。百粒重和小区产量极显著地高于对照,籽粒总糖量有所提高,以可溶性糖含量提高尤为显著。     

INFLUENCE OF CORN (ZEA MAYS L.) CULTIVAR DEVELOPMENT ON RESIDUE PRODUCTION

The amount and composition of crop residues added to soil in agroecosystems can influence decomposition processes and soil organic matter levels. This study aimed to evaluate residues (quantity and quality) of different corn cultivars commonly used in Brazilian cropping systems. The experiment was conducted for two seasons (2005/2006 and 2006/2007) in Rolândia, Paraná State, Brazil. Ten corn cultivars that represent five degrees of breeding development (i.e., landrace, commercial variety, double cross, triple cross, and single cross hybrids) were evaluated. At harvest, carbon (C) and nitrogen (N) of non-yield residue and grain were determined. Except for grain C, other measures (grain N concentration, residue C and N concentration, and C:N ratio) varied among cultivars. In general, the hybrids had higher residue C and lower residue N concentrations than the landraces and commercial varieties. Findings suggest that breeding selection may have altered residue production and composition, which may influence soil C dynamics.     

水稻品种对石灰性土壤缺Zn耐性机理的研究

选用缺Zn敏感水稻品种IR26和耐缺Zn水稻品种IR8192－31－2,采用营养液培养的方法,研究了水稻品种耐石灰性土壤Zn与HCO^-3关系的生理生化机制。在低锌浓度下,HCO^-3严重抑制敏感品种根系生长,而对耐性品种影响很小;HCO^-3增加增加了两种水稻品种根中的苹果酸和柠檬酸浓度,但敏感品种增加的幅度大,以上结果表明HCO^-3对敏感品种根生长的抑制,并诱发缺Zn是由于根中有机酸过度积累导致的,HCO^-3显著提高敏感品种根中PEP羧化酶活性可能是HCO^-3增加其有机酸只累,从而影响根生长及Zn有效性机理的重要过程。     

STUDY ON THE EFFECTS OF NITROGEN DEFICIENCY ON GRAIN IRON AND ZINC CONCENTRATIONS OF LANDRACE AND BRED WHEAT VARIETIES IN CHINA

It has been reported that nitrogen (N) deficiency can significantly reduce grain iron (Fe) and zinc (Zn) concentrations in wheat. Here, we investigated the grain Fe (GFeC) and Zn (GZnC) concentrations of 42 Chinese wheat varieties grown in a field trial under low and high N conditions. Analysis of variance revealed that both GFeC and GZnC significantly differed among varieties and between N treatments, and significant interactions existed between variety and N treatment. The GFeC under the low N condition was 94.8% of that under high N condition, ranging from 79.4% to 112.7%; the GZnC under low N condition was 74.8% of that under high N condition, ranging from 59.5% to 102.5%. Wheat varieties with high GFeC and GZnC under both N conditions were identified, and this kind of varieties is desirable in breeding wheat with enriched Zn and Fe under a range of soil N conditions.     

USING PSEUDOMONAS SPP. AND ARBUSCULAR MYCORRHIZAL FUNGI TO ALLEVIATE THE STRESS OF ZINC POLLUTION BY CORN (ZEA MAYS L.) PLANT

The objective was to test the single and combined use of Pseudomonas spp. and Glomus versiforme on the stress of high zinc (Zn) concentration in soil on corn growth as such data are little. Accordingly, in a greenhouse research work the effects of Zn concentrations (control, 100, 200 and 300 mg kg ^?1 ) and the microbial treatment (control, Pseudomonas spp. and G. versiforme) were tested on corn (single cross 704) growth. Almost three months after planting, plants were harvested. Plant dry weight and Zn uptake were determined. Zn significantly (P = 0.01) affected different measured parameters. The microbes increased plant dry weight related to the control treatment and the highest increase was related to the bacterial application (1.28 times higher). Both bacteria and mycorrhizal fungi and their combined use decreased Zn concentration in plant. The right combination of soil microbes can efficiently affect the process of bioremediation with respect to plant properties.     

EFFECT OF NITROGEN SOURCES AND RATES ON YIELD AND QUALITY OF SILAGE CORN

The objective of this study was to determine the effect of nitrogen (N) application source and rate on silage corn (Zea mays L.). Urea, ammonium nitrate, and ammonium sulfate were compared at 50, 100, 150, and 200 kg N ha^?1. The application of ammonium sulfate produced the highest plant height, leaf area index (LAI), total yield, and stem, leaf, and ear dry matter, followed by ammonium nitrate and urea. However, nitrogen sources had no marked effects on the content of protein, ash, oil, soluble carbohydrates, acid detergent fiber (ADF) and neutral detergent fiber (NDF). As the rate of nitrogen increased plant height, LAI, total yield, and stem, leaf, tassel, and ear dry matters, and protein, ash and oil contents increased while soluble carbohydrates, ADF, and NDF contents decreased. Ammonium sulfate was the most effective N source on production and 200 kg N ha^?1 was the most effective N rate on corn yield and quality.     

肥密逆境对玉米果穗高维几何大小的影响及其与产量的关系

为认识玉米果穗体积等高维几何大小特征的动力学特性,明确肥密逆境对玉米果穗大小特征的影响及其与产量的关系,借助图像处理采集穗长(L)、穗粗(D)、穗正纵截面面积(简称穗面积,S)和穗体积(V),对2个玉米品种在无肥高密条件下以及除叶的效果进行典型变量分析、方差分析及曲线拟合.结果显示,吐丝时玉米果穗体积占其终值的7%、穗...     

提高玉米花药培养愈伤组织诱导率的研究

以3个玉米(Zeo mays L.)自交系为父本分别与其它一些自交系杂交。将杂交 F_1和花粉纯系作为接种材料来源,结果表明:以易诱导的自交系作为杂交亲本之一,其杂种 F_1花药愈伤组织诱导率和绿苗分化率高。玉米幼穗预处理试验结果表明:采种前一周分2次注射10ml 0.6％硼酸入植株幼茎内,其愈伤组织诱导率较高。     

EFFECT OF REDUCED SEED AND APPLIED ZINC ON ZINC EFFICIENCY OF WHEAT GENOTYPES UNDER ZINC DEFICIENCY IN NUTRIENT SOLUTION CULTURE

Improving zinc efficiency of cereals especially wheat under zinc deficiency is a priority area of research to determine and manipulate the plant factors that govern zinc uptake and utilization. Experiments conducted to ascertain variability and also the contribution of seed zinc (complete seed and half seed) to zinc efficiency in diverse wheat genotypes raised on zinc sufficient and deficient nutrient solution, showed wide genetic variability and general deficiency response such as, increase in root to shoot ratio and decrease in leaf chlorophyll, superoxide dismutase activity, total plant zinc concentration, and uptake. Since difference in zinc deficiency response were more distinct at the initial growth stage, seed zinc could be crucial for determining plant establishment, vigor, and yield. A few exceptional genotypes, where cutting seed zinc supply infect triggered growth, root characteristics, zinc uptake and use efficiency were identified and their zinc uptake capacity on low zinc soil was measured. The difference in zinc efficiency was attributable to phytosiderophore release capacity of the genotypes.     

ROOT ZONE TEMPERATURE INFLUENCES ZINC REQUIREMENT OF MAIZE CULTIVARS ON A CALCAREOUS LOAM SOIL

The zinc (Zn) requirement of a maize (Zea mays L.) hybrid (‘FHY-396’) and an indigenous variety (‘EV-7004’) was measured at low (22.4 ± 5°C) and high (28.8 ± 5°C) root-zone temperatures (RZT). Four Zn rates (0, 3, 9 and 27 mg kg^?1 soil) were applied to a calcareous loam soil in pots for the glasshouse study. Shoot and root dry matter yields were significantly more at the higher RZT. Regardless the RZT, maximum relative shoot dry matter yield in hybrid and variety was produced, respectively, at 9 and 3 mg Zn kg^?1 soil. Zinc concentration in roots and shoots of both the cultivars increased with Zn rates and it was significantly more at the higher RZT. Cultivars differed in critical Zn concentration (C_ZnC) required for maximum shoot dry matter yield. The C_ZnC ranged from 25 to 39 μg Zn g^?1 plant tissue for optimum growth of both the cultivars at low and high RZT.     

改良剂对玉米和大豆间作植株锌铬积累的影响

通过盆栽试验,研究改良剂石灰和过磷酸钙对玉米、大豆间作植株各器官锌铬积累的影响。结果表明,不同改良剂处理后,能显著降低土壤中锌、铬有效态含量,植株各器官锌含量为:对照>低浓度石灰>高浓度石灰;铬含量为:对照>高浓度过磷酸钙>低浓度过磷酸钙,单作>间作。在间作下施用低浓度过磷酸钙改良效果最优,其中玉米根、茎、叶的锌、铬含量分别比只施用低浓度过磷酸钙单作降低30.72%、35.96%和29.51%,69.98%、64.21%和51.56%;比不施加改良剂的对照间作玉米降低55.57%、59.68%和66.57%,64.10%、76.79%和80.75%;大豆根、茎、叶的锌、铬含量分别比其只施用低浓度过磷酸钙单作降低0.26%、4.91%和16.42%,14.25%、8.16%和23.33%,比不施加改良剂的对照间作降低63.95%、69.54%和65.49%,54.15%、57.14%和57.14%。间作条件下,低浓度过磷酸钙处理在不增加大豆对锌铬吸收的前提下,大幅降低玉米对重金属的吸收,显著增加玉米产量。     

FOLIAR SPRAY EXPERIMENTS IDENTIFY NO BORON DEFICIENCY BUT MOLYBDENUM AND MANGANESE DEFICIENCY FOR CANOLA GRAIN PRODUCTION ON ACIDIFIED SANDY GRAVEL SOILS IN SOUTHWESTERN AUSTRALIA

Since the early 1990s canola (oilseed rape, Brassica napus L.) has become a major crop species grown on the predominantly sandy soils of southwestern Australia. Numerous studies have been undertaken to determine the fertilizer requirements of the crop in the region. This paper reports results of a field experiment conducted at three sites on typical acidified (pH [Ca] ～4.6) sandy gravel soils to identify if molybdenum (Mo), manganese (Mn) or boron (B) were deficient for canola grain production. Different levels of each element, separately or as mixtures, were applied as foliar sprays at mid-flowering. Maximum grain yield responses of ～11–20% to applied Mo, as sodium molybdate (39% Mo), were obtained when 40 g Mo/ha was applied. Maximum grain yield responses of ～13–28% to applied Mn were achieved by applying 1000 g ha^?1 Mn, as manganese sulfate (24% Mn). A mixture of 40 g Mo ha^?1 and 1000 g Mn ha^?1 increased grain yields by ～15–38%. Boron, applied as borax (11% B), sprayed individually or in combination with Mo or/and Mn, had no effect on grain yields. None of the foliar spray treatments had any effect on oil concentration in canola grain. The sprays did not cause any visible damage to foliage. Soil acidification has been shown to induce Mo deficiency for cereal crops in the region and both soil acidification and induced Mo deficiency are alleviated by applying sufficient lime to raise pH of top 10 cm soil to 5.5 or greater, and this strategy should also apply to canola. Further research is required to determine the fertilizer Mn requirements for canola grain production in the region.     

APPLICATION OF INCREASING LEVELS OF ZINC TO SOIL REDUCED ACCUMULATION OF CADMIUM IN LUPIN GRAIN

Yellow lupin (Lupinus luteus L.) and narrow-leafed lupin (L. angustifolius L.) are grown as grain legumes in rotation with spring wheat (Triticum aestivum L.) on acidic sandy soils of south-western Australia. Yellow lupin can accumulate significantly larger cadmium (Cd) concentrations in grain than narrow-leafed lupin. A glasshouse experiment was undertaken to test whether adding increasing zinc (Zn) levels to soil increased Zn uptake by yellow lupin reducing accumulation of Cd in yellow lupin grain. Two cultivars of yellow lupin (cv. ‘Motiv’ and ‘Teo’) and 1 cultivar of narrow-leafed lupin (cv. ‘Gungurru’) were used. The soil was Zn deficient for grain production of both yellow and narrow-leafed lupin, but had low levels of native soil Cd (total Cd <0.05 mg kg^?1) so 1.6 mg Cd pot^?1, as a solution of cadmium chloride (CdCl₂·H₂O), was added and mixed through the soil. Eight Zn levels (0–3.2 mg Zn pot^?1), as solutions of zinc sulfate (ZnSO₄·7H₂O), were added and evenly mixed through the soil. Yellow lupin accumulated 0.16 mg Cd kg^?1 in grain when no Zn was applied, which decreased as increasing Zn levels were applied to soil, with ～0.06 mg Cd kg^?1 in grain when the largest level of Zn (3.2 mg Zn pot^?1) was applied. Low Cd concentrations (<0.016 mg Cd kg^?1) were measured in narrow-leafed lupin grain regardless of the Zn treatment. When no Zn was applied, yellow lupin produced ～2.3 times more grain than narrow-leafed lupin, indicating yellow lupin was better at acquiring and using indigenous Zn from soil for grain production. Yellow lupin required about half as much applied Zn as narrow-leafed lupin to produce 90% of the maximum grain yield, ～0.8 mg pot^?1 Zn compared with ～1.5 mg Zn pot^?1. Zn concentration in whole shoots of young plants (eight leaf growth stage) related to 90% of the maximum grain yield (critical prognostic concentration) was (mg Zn kg^?1) 25 for both yellow lupin cultivars and 19 for the narrow-leafed lupin cultivar. Critical Zn concentration in grain related to 90% of maximum grain yield was (mg Zn kg^?1) 24 for both yellow lupin cultivars compared with 20 for the narrow-leafed lupin cultivar.     

CUMULATIVE AND RESIDUAL EFFECTS OF ZINC SULFATE ON GRAIN YIELD,ZINC, IRON,AND COPPER CONCENTRATION IN CORN AND WHEAT

Re-application of zinc (Zn) sulfate for corn (Zea mays L.) production in rotation of wheat-corn has varied effects on yield of crops grown in Zn deficient soils. Therefore, this study was done as split plots in a complete randomized block design (CRBD) where the main plots were control with and without Zn application in wheat (Triticum aestivum L.) production. Sub-plots were of control, without Zn fertilizer, base application of 75 kg per hectare (kg Zn ha^?1), 25% and 50% less than base application and as foliar spray in combination with the 4 soil Zn treatments for corn production. Effect of previous Zn application on grain Zn concentration of corn was significant (P < 0.01). Zinc concentrations in treatments of without previous Zn (nil Zn) application and with Zn application were 28.1 and 31.8 mg kg^?1, respectively. Soil application of 75 kg ha^?1 and foliar application of Zn sulfate gave the highest yield (8853 kg ha^?1) showed an increase of 25 percent in compared with nil-Zn. Although re-application of Zn has small effect on yield, but resulted in was the highest grain concentration.     

AGRONOMIC EFFICIENCY AND PROFITABILITY OF P-FERTILIZERS APPLIED AT DIFFERENT PLANTING DENSITIES OF MAIZE IN NORTHWEST PAKISTAN

The use of appropriate source of phosphorus (P) fertilizer at different planting densities has considerable impact on growth, grain yield as well as profitability of maize (Zea mays L). Field experiment was conducted in order to investigate the impact of P sources [(S₀ = P not applied, S₁ = SSP (single super phosphate) S₂ = NP (nitrophos), and S₃ = DAP (diammonium phosphate)] on maize growth analysis, yield and economic returns planted at different planting densities (D₁ = 40,000, D₂ = 60,000, D₃ = 80,000, and D₄ = 100,000 plants ha^?1) at the New Developmental Agricultural Research Farm of Khyber Pakhtunkhwa Agricultural University, Peshawar, Pakistan, during summer 2006. This paper reports the profitability data with two objectives: 1) to compare agronomic efficiency and profitability of P-fertilizers, and 2) to know whether plant densities affect agronomic efficiency and profitability of P-fertilizers. Application of DAP and SSP resulted in higher partial factor productivity (PFP) (63.58 and 61.92 kg grains kg^?1 P), agronomic efficiency (AE) (13.01 and 13.71 kg grains kg^?1 P) and net returns (NR) (Rs. 16,289 and 16,204 ha^?1), respectively, while NP stood at the bottom in the ranking with lower PFP (57.16 kg grains kg^?1 P), AE (8.94 kg grains kg^?1 P) and NR (Rs. 4,472 ha^?1). Among the plant densities, D₃ stood first with maximum PFP (69.60 kg grains kg^?1 P), AE (18.21 kg grains kg^?1 P) and NR (Rs. 21,461 ha^?1) as compared to other plant densities. In conclusion, the findings suggest that growing maize at D₃ applied with either SSP or DAP is more profitable in the wheat-maize cropping system in the study area.     

EFFECTS OF CALCIUM AND SALINITY STRESS ON QUALITY OF LETTUCE IN SOILLESS CULTURE

Abstract

Fine fescues (Festuca spp.) are generally considered acid tolerant compared to other cool‐season turfgrasses. However, there is little information on aluminum (Al) tolerance of fine fescues at both the species and cultivar levels. The objectives of this study were to identy cultivars of fine fescues with superior ability to tolerate Al, and compare the Al tolerance of endophyte infected and endophyte‐free cultivars in Al tolerance. A total of 58 cultrvars of fine fescues belonging to five species or subspecies [14 hard fescue (F. longifolia Thuill), 25 Chewings fescue (F. rubra L. ssp. commutata Gaud), 15 strong creeping red fescue (F. rubra L. ssp. rubra), two slender creeping red fescue (F. rubra L. ssp. trichophylla), and two sheep fescue (F. ovina L.)] were selected from the 1993 National Fineleaf Fescue Test and screened under greenhouse conditions using solution culture, sand culture, and acid Tatum soil (Clayey, mixed, thermic, typic, Hapludult). The acid Tatum soil had 69% exchangeable Al and a pH of 4.4. An Al concentration of 640 μM and a pH of 4.0 were used in solution culture and sand culture screening. The grasses were seeded and grown for three weeks before harvesting. Aluminum tolerance was assessed by measuring relative root length, shoot length, root weight, shoot weight, and total dry matter. Differences in Al tolerance were identified at both the species and cultivar level based on relative growth were as follows: i) hard fescue and Chewings fescue were more Al tolerant than strong creeping red fescue; ii) within species or subspecies, significant differences were found among cultvars of Chewings fescue, strong creeping red fescue, slender creeping red fescue, and sheep fescue; whereas no difference was observed among the hard fescue cultivars; and iii) the cultivars containing endophyte exhibited greater Al tolerance compared the eudophyte‐free cultivars. The results indicate that fine fescues vary in Al tolerance and there is potential to improve Al tolerance with breeding and to refine their management recommendations regarding soil pH.