DAIRY MANURE AND NITROGEN FERTILIZER EFFECTS ON RESIDUAL NITRATE AND PHOSPHATE,AND WHEAT YIELD IN A SANDY CLAY LOAM SOIL

Dairy manure (DM) rates of [0 (DM₀), 30 (DM₃₀₎), 60 (DM₆₀) Mg ha^?1] and three nitrogen (N) rates [0 (N₀), 125 (N₁₂₅), 250 (N₂₅₀) kg ha^?1] were tested in a sandy clay loam, to evaluate their effects on growth and yield of wheat crop (Triticum aestivum L.), residual nitrate nitrogen (NO₃-N) and phosphorus (P) concentrations in the surface soil, and selected soil physical measurements [saturated hydraulic conductivity (Ksat), and bulk density (BD)]. Increasing N and DM rates gave higher wheat yields, increased concentrations of residual NO₃-N and P in the surface soil and improved Ksat and BD. Highest grain yield of 3.8 Mg ha^?1 (70.3% more than the control) was observed in DM₆₀ × N₂₅₀ treatment. Residual accumulation of N-NO₃ and P in the surface soil at high N and/or DM application rates suggests the need to carefully manage N and DM inputs on farm fields to avoid environmental contamination.     

磷素水平对大豆氮素积累及产量的影响

利用砂培方法和15N示踪技术研究了磷素水平对大豆氮素积累、根瘤固氮和产量的影响。结果表明:大豆植株氮素积累、根瘤固氮和产量均随磷素营养水平的提高而呈单峰曲线变化,营养液磷素浓度31mg/L左右时达到峰值,当营养液磷素浓度达11mg/L时,再提高磷素浓度对大豆根瘤固氮率无明显促进作用;而对于大豆植株氮素积累、根瘤固氮量和产量,只有当营养液磷素浓度达到21mg/L时,再提高磷素浓度才无明显促进所用,表明满足根瘤固氮的磷素营养水平较产量形成的水平要求低。     

施氮水平对大豆氮素积累与产量影响的研究

以绥农14为材料,利用砂培和15N标记的方法研究了施氮水平对大豆氮素积累及产量的影响。结果表明:随着施氮水平的提高,大豆全株氮素积累量及叶柄、荚皮、籽粒中氮素积累量呈现先增加后下降的趋势;高氮水平增加了叶片和茎中氮素积累量,N150较N0处理叶片的氮素积累量增加了3倍,而茎增加了5倍,但减少了根中氮素积累,降低了大豆全株和籽粒中根瘤固氮量及其所占比例,降低了肥料氮和根瘤氮的收获指数,其中根中氮素积累N150较N50处理降低了60.3%,全株根瘤氮和籽粒中根瘤氮N150较N0分别降低了74.9%、85.7%,肥料氮的收获指数N150较N50降低19.8%,根瘤氮的收获指数N150较N0降低25.5%。随着施氮水平的增加,大豆产量也呈现先增加后下降的趋势,施氮水平的增加促进了大豆植株株高、结荚高度和始荚节位的显著增加,但对节数没有明显影响,N150和N0比较株高增加了55.2%,结荚高度增加了199.7%,始荚节位增加了142.9%。     

EFFECT OF NITROGEN AND SULFUR FERTILIZATION ON YIELD COMPONENTS,SEED AND OIL YIELDS OF CANOLA

Field experiments were conducted to evaluate the effects of nitrogen (N) and sulfur (S) levels and their methods of application on canola. Branches plant^?1, pods plant^?1 and biological yield significantly increased with increase in nitrogen level and no significant increase in seed pod^?1 and seed and oil yields occurred beyond 120 kg N ha^?1. However, thousand seed weight consistently decreased with increasing level of nitrogen. Pods plant^?1 and biological yield continually increased with increase in sulfur level. Alternatively, significant increase in branches plant^?1, seed pod^?1, seed weight, seed and oil yields was noted with increase in sulfur level up to 40 kg ha^?1. Applications of sulfur and nitrogen in split significantly decreased seed yield as compared to sole applications. It is concluded that sulfur and nitrogen application as sole at the rate of 40 and 120 kg ha^?1, respectively performed better than the rest of their levels and method of application.     

施肥对大白菜中氮同位素及硝酸盐含量的影响

研究不同肥料配施处理对土壤和大白菜中稳定性氮同位素丰度(δ15 N‰)及硝酸盐含量的影响.结果表明,随着有机肥比例的降低,大白菜中δ15 N和硝酸盐含量分别呈现逐渐降低和增加的趋势,对照大白菜中δ15 N和硝酸盐含量分别为+9.355‰和1459mg/kg;纯有机肥(100%-O)和纯化肥(100%-C)处理大白菜中δ...     

INFLUENCE OF NITROGEN FERTILIZATION ON NICKEL ACCUMULATION AND CHEMICAL COMPOSITION OF COFFEE PLANTS DURING FRUIT DEVELOPMENT

Nutritional and physiological significance of micronutrients in coffee plants, especially with regard to nickel (Ni) is still unknown. The dynamics of nitrogen (N), phosphorus (P), potassium (K) and Ni accumulation in coffee fruits, as well as their relationships with total soluble protein, amino acids, reducing sugars, and starch content during coffee fruit development (green, ripe, and dry fruits), were investigated. Coffee trees received three N fertilizer rates (0, 150, and 300 kg of N ha^?1) as ammonium sulfate split into three applications per year. Nitrogen fertilization increased reducing sugars and starch concentrations in ripe fruits. In contrast, green fruits showed the highest amino acid and Ni concentrations. Fruit Ni concentration decreased in both green and ripe fruits as N rates increased; thus, indicating the possibility of either a N-associated dilution effect on Ni concentration or that Ni uptake by roots and/or transport to developing fruit was limiting. Plant nutritional status and fruit development stage influenced the coffee grain chemical composition. Furthermore, the variation in reducing sugars and starch content was more closely linked to the stage of fruit development than to N supply. A supposed relationship among the decreased of caffeine, starch, amino acids, and proteins with Ni content during green fruit development suggests a fundamental role for Ni in coffee fruit ripening. The interaction between N and Ni metabolism during fruit ripening might influence the chemical parameters involved in the coffee grain quality. This is the first report documenting changes in Ni concentrations of coffee fruit as a function of N fertilization rates and the development stage, but further research is needed to better understand the significance of N-Ni interaction in developing coffee fruit.     

INFLUENCE OF NITROGEN SUPPLY ON CADMIUM ACCUMULATION IN POTATO TUBERS

The effect of different levels and forms of nitrogen (N) fertilizer on cadmium (Cd) concentrations in potato (Solanum tuberosum L.) tubers, a large component of the northern European diet, was investigated with the aim of decreasing the Cd content. A high and a low Cd-accumulating cultivar were used in two field trials and a pot experiment. The N fertilizers tested were balanced N- phosphorus (P)- potassium (K) 11-5-18 + micronutrients, alkaline calcium nitrate and acidic ammonium sulfate at levels of 60, 160, and 240 kg N ha^?1 at planting or (for the higher N doses) split between two or three occasions. The Cd concentration in tubers of both cultivars decreased when increasing the N fertilizer from 60 to 160 or 240 kg N ha^?1, indicating that Cd uptake and translocation are not positively correlated to the growth rate of the potato plant. A strong positive linear correlation was found between the Cd concentration in leaves at 77 days after planting and the Cd concentration in tubers at harvest, irrespective of N treatment, although the Cd concentration was three-fold higher in the leaves. The genetic variation in leaf and tuber Cd accumulation was consistent, regardless of the form of N fertilizer used. Ammonium sulfate decreased soil pH and increased tuber Cd concentration in both cultivars compared with NPK fertilizer, possibly due to increased amounts of plant-available Cd arising from the pH decrease after ammonium sulfate application. The tuber Cd concentration in the low Cd-accumulating cultivar increased when fertilized with calcium nitrate, an effect attributed to Cd availability being influenced by the increased Ca²⁺ concentration.     

不同氮肥用量对蔬菜硝态氮累积的影响

利用盆栽试验,研究了氮肥用量对蔬菜硝态氮累积的影响。结果表明,施用氮肥使蔬菜的生长量提高1.1～6.1倍,但增长并不与氮肥用量同步。氮肥用量较高时,蔬菜生长受到抑制,生长量有降低趋势;硝态氮含量却随氮肥用量增加而不断升高,两者呈显著正相关（r=0.933～0.957）。蔬菜各器官、部位的硝态氮含量存在明显差异。不施氮肥时,根的硝态氮含量大于茎叶,茎又大于叶;施氮后根的含量小于茎叶,茎小于叶;无论施氮与否,叶柄的含量均高于叶片。把蔬菜的生长、硝态氮吸收及还原转化联系起来分析,可以看出,增加氮肥用量虽然提高了硝酸还原酶活性,但硝态氮的还原作用仍小于吸收,从而导致蔬菜体内出现硝态氮累积。而且,随氮肥用量增加,硝态氮累积量的增加远超过了生长量的提高,使硝态氮含量迅速升高。     

施氮量对间作玉米土壤硝态氮累积量及氮肥利用率的影响

通过田间定位试验,监测了不施氮和不同施氮水平(分别为210、420和630kg.hm-2)下间作玉米各关键生育时期0～200cm土层硝态氮累积量的动态变化、玉米产量及其构成,计算分析了间作玉米的氮肥利用率。研究结果表明,间作玉米0～200cm土层土壤硝态氮累积量总体表现为0～60cm土层>60～200cm土层。0～60cm土层土壤硝态氮累积量呈"M"形变化,即玉米播种前和玉米大喇叭口期出现高峰,小麦播种前、玉米拔节期和玉米收获后出现低谷。60～120cm和120～200cm土层土壤硝态氮累积量呈倒"V"形变化,总体在玉米大喇叭口期前后出现高峰值,210～630kg.hm-2施氮处理下120～200cm土层的硝态氮累积量较不施氮处理分别高出149.1%、115.6%和126.3%。随着施氮量的增加,间作玉米穗长、穗粒数、穗重呈增大趋势,秃顶呈降低趋势,增产幅度依次减小,氮肥利用率依次降低。     

NITRATE ACCUMULATION IN SPINACH AS INFLUENCED BY SULFUR AND PHOSPHORUS APPLICATION UNDER INCREASING NITROGEN LEVELS

Nitrate (NO₃) accumulation by spinach was studied under increasing nitrogen (N) levels (60, 120 and 240 kg N ha^?1) along with sulfur (45 kg S ha^?1) and phosphorus (P; 90 kg P₂O₅ ha^?1) application. Plants were harvested at 50 and 65 days after sowing. Plant samples were analyzed for NO₃-N and total N, P, S, potassium (K), calcium (Ca), and magnesium (Mg). Radio assay of 35S was done to estimate percent sulfur derived from fertilizer and percent fertilizer sulfur utilization. Spinach maintained a very high level of NO₃-N in its tissue throughout the growing period. NO₃-N was increased with increasing nitrogen level and was reduced with phosphorus and sulfur application and also with advancement in growth. Total N, P, S, K, Ca and Mg uptake were increased with increasing nitrogen levels as well as with application of sulfur and phosphorus. Sulfur application caused increase in percent sulfur derived from fertilizer and percent utilization of fertilizer sulfur.     

INFLUENCE OF NITROGEN AND SULFUR ON YIELD AND SEED QUALITY OF THREE CANOLA CULTIVARS

In order to investigate the effect of nitrogen (N) and sulfur (S) fertilizers on yield and seed quality of three canola cultivars, a factorial based on randomized complete block experiment was conducted during 2005–2006 in Iran. Treatments included four nitrogen rates (0, 75, 150, and 225 kg N ha^?1 source of urea), four sulfur rates (0, 100, 200, and 300 kg S ha^?1), and three cultivars (‘Pf’, ‘Option-500’, and ‘Hyola-401’). Results indicated cultivar had a significant effect on all studied traits. ‘Option-500’ and ‘Hyola-401’ cultivars had the highest seed yield, protein content, and N:S ratio in seed. The levels of 150 and 220 kg N ha^?1 resulted in the maximum protein content. Increasing N levels resulted in N content and decreased the oil content. The interaction effect between S and N levels showed the highest N content in seed was obtained with 300 kg S ha^?1 and 225 kg N ha^?1.     

YIELD,FRUIT QUALITY AND NITROGEN UPTAKE OF ORGANICALLY AND CONVENTIONALLY GROWN MUSKMELON WITH DIFFERENT INPUTS OF NITROGEN,PHOSPHORUS, AND POTASSIUM

The effects of varied amounts of fertilization on yield, fruit quality, and nitrogen (N) uptake of muskmelons (Cucumis melo L. var reticulatus Naud) grown under both organic and conventional farming conditions were evaluated. Organic fertilizer (0.0, 0.55, 1.1, and 2.2 kg m^?2) and mineral fertilizers containing the same amounts of estimated plant available nutrients [N, phosphorus (P), and potassium (K)] were applied to organic and conventional farming plots, respectively, in both the spring and autumn seasons of 2005. In comparison to conventional farming conditions, muskmelons grown under organic farming conditions had the same yield, total soluble solids (TSS) and soluble sugar contents in both growing seasons, and fruit pulp nitrate content was significantly reduced by 12% on average in spring and 16% on average in autumn. At harvest maturity the aboveground plant N concentration was significantly higher in the conventional treatments than in the organic treatments. At the vine growth stage, the plant N concentrations were similar in all treatments in both seasons. The ratios of nitrate N to total N amount in aboveground biomass were higher in conventional and high fertilized organic treatments than in low or not fertilized organic treatments under limited N supply from the soil. Muskmelon plants absorbed mainly inorganic N, and the protein N fraction in the xylem sap was larger than the amino acid N fraction. Plants grown in the organic system had a higher proportion of organic N in their xylem sap, especially when manure input was low.     

氮肥对大白菜硝酸盐累积的影响及合理施用量研究

对宁夏灌淤旱耕人为土氮(N)肥与大白菜产量及菜体和土体中硝酸盐累积的关系进行了田间试验研究。结果表明,在设计范围内,银川平原复种大白菜的产量及净菜率与施N量成正比;施N肥增加大白菜硝酸盐含量;复种大白菜的最高产量施N量为448.5㎏/hm2,最佳产量施N量为427.5㎏/hm2;大白菜外叶硝酸盐含量高于内叶,内叶硝酸盐含量随施N肥量的增加而增加,外叶硝酸盐含量在高施N时,随生育期延长而增加;施用N肥明显增加土体各土层中的硝态N含量。     

施肥水平对冬大麦干物质和氮素积累与转运的影响

为合理利用氮肥,进一步提高大麦产量和品质,以扬饲麦3号、港啤1号、扬农啤2号和Frankin共4个品种为供试材料,研究了0(CK),90(NL),180(NM)和270kg/hm2(NH)4个氮肥水平下冬大麦干物质和氮素积累、转运及对籽粒贡献的规律。结果表明,随着施氮量的提高,大麦干物质花前积累量呈增加趋势,积累率及对籽粒的贡献率呈下降趋势,各器官的转运量在NM处理(180kg/hm2)范围内呈增加趋势,高于此范围则下降。氮素营养花前积累量和转运量各品种均呈上升趋势,花前积累率、转运率和对籽粒氮的贡献率都呈下降趋势。不同品种不同氮肥处理下大麦干物质转运量以茎秆为最大,转运率大部分以芒壳+穗轴为最高,对籽粒的贡献率以茎秆为最高。各器官氮素转运量以叶片最高,转运率以芒壳+穗轴最大,氮素转运对籽粒的贡献率以叶片最高。大麦各品种籽粒产量与施氮量呈二次曲线关系,氮素积累量与施氮量呈显著线性正相关关系。表明在本试验条件下,大麦最高产量的最佳施氮范围为212.42～261.97kg/hm2。     

氮素水平对不同氮效率基因型水稻的物质生产与分配的影响

研究了在群体水培条件下,3种氮素水平(5、15和25mg.kg-1)对6种不同氮效率利用基因型迟熟中粳水稻物质生产与分配的影响。结果表明:氮素水平、基因型对水稻氮素干物质生产效率(NUEdm)、氮素籽粒生产效率(NUEg)均有极显著的影响。6种不同氮效率基因型可分成氮高效和氮低效利用型2类。NUEdm在2类基因型水稻中总体上均随着氮素水平升高呈现上升趋势;而NUEg在氮低效基因型中表现为随氮素浓度升高而先升后降。在水稻的4个关键生育期,不同氮素水平、2类基因型之间水稻干物质积累量差异显著。成熟期,氮素水平对水稻茎鞘、根、穗的干物质分配比例影响显著,对叶片干物质分配比例影响不显著。相同氮素水平下,就平均值而言,水稻茎鞘、叶片、根系干物质比例均表现为氮低效基因型>氮高效基因型,而穗的干物质比例均表现为氮高效基因型>氮低效基因型。氮素水平对不同基因型水稻产量影响显著,同一氮素水平下均表现为氮高效型基因型水稻产量显著高于氮低效型基因型,且施氮量越大差异越大。相关分析表明,水稻各关键生育期的干物质生产量、产量、每穗粒数均与氮素水平、基因型的NUEg、NUEdm显著或极显著相关,与成熟期水稻各器官干物质分配比例相关性则相对较弱。     

移栽叶龄对水稻氮素吸收利用及~(15)N-肥料去向影响

利用15N示踪技术研究了不同叶龄移栽对水稻产量、氮肥吸收利用及其氮素去向的差异。结果表明,随移栽叶龄推迟,水稻产量显著降低,籽粒与秸秆氮肥吸收量、肥料利用率及其残留量也降低,而氮素损失增加。水稻所吸收的氮素约2/3来源于土壤氮,1/3来源于当季肥料施的氮。肥料利用率为20.8%~25.7%,氮肥残留率为17.9%~32.2%,有42.1%~61.3%的肥料损失。无论哪种叶龄移栽条件下,肥料主要残留在0~20cm土层中。研究表明水稻早栽能增加产量、提高肥料利用率,减少肥料损失,降低氮素对环境的污染。     

YIELD AND YIELD COMPONENTS OF HYBRID RICE AS INFLUENCED BY NITROGEN FERTILIZATION AT DIFFERENT ECO-SITES

Hybrid rice (Oryza sativa L.) cultivars play an important role in rice production due to its high yield potential. Optimum nitrogen (N) rate is necessary to achieve the maximum yield of hybrid. The main objective of this study was to reveal the responses of yield and yield component of hybrid rice ‘Eryou 107’ to different N rates in Nanjing and Taoyuan, a special eco-site. Leaf area index (LAI), dry matter accumulation was also compared. Rice yield showed a quadratic response to N rates at both sites with maximum yields approximately 10 t ha^?1 at the 195 kg ha^?1 N rate in Nanjing and maximum yield above 18 t ha^?1 at the 375 kg ha^?1 N rate in Taoyuan. Panicle per m² was positively linear related to N rate at both sites in both years, while spikelets per panicle showed a quadratic relation. Larger sink size was the primary contributor to higher yields in Taoyuan compared with Nanjing, and panicle per m² was the main cause. With the increasing N rate, LAI increased linearly and the dry matter accumulation first increased than declined at both sites. Greater effects of N rates on yield and yield components, LAI, and biomass was observed in Taoyuan than Nanjing. Higher LAI, biomass, and larger sink size resulted in the higher yields and more N rate for maximum yields in Taoyuan, compared with Nanjing.     

SILICON ACCUMULATION AND ITS INFLUENCE ON SOME OF THE LEAF CHARACTERISTICS,MEMBRANE STABILITY AND YIELD IN RICE HYBRIDS AND VARIETIES GROWN UNDER AEROBIC CONDITIONS

Efforts to minimize water use in rice cultivation and stress tolerance are important in the present climate change scenario. Silica solubilizers might help in understanding the tolerance of plants to water deficit conditions or aerobic conditions. Rice cultivation in combination with silica was applied in the form of fertilizers (sodium silicate) and solubilizers (Imidazole and glycine) was studied in experimental farm and also in farmer's field. The varieties used were ‘KrishnaHamsa' (KH), ‘Rasi', ‘Jaya', hybrids ‘PA-6201' and ‘PHB-71' under aerobic conditions both in wet (Kharif) and dry (rabi) seasons. Transmission electron microscopy in this study provided evidence that silicon was deposited in the epidermal cell wall and the intercellular space of the silicon-treated rice leaves. The epidermal cell wall accumulation was absent in the control plants. Genotypic variation and treatment influences were observed for relative water content and cell membrane stability. Among the different rice cultivars ‘Rasi' followed by ‘PHB-71' and PA- 6201, were able to maintain cell membrane stability and chlorophyll content. Leaf rolling, chlorophyll, relative water contents, and dark adapted chlorophyll fluorescence were superior under aerobic conditions with application of solubilizers. However, significant differences in stomatal conductance were seen between seasons and genotypes. The silicon treated plants were able to maintain similar yields under aerobic conditions also as that of irrigated controls.     

EFFECT OF SWINE MANURE EXTRACT ON LEAF NITROGEN CONCENTRATION,CHLOROPHYLL CONTENT,TOTAL POTASSIUM IN PLANT PARTS AND STARCH CONTENT IN FRESH TUBER YIELD OF CASSAVA

The effects of swine manure extract (SME) as foliar fertilizer (FSME), soil fertilizer (SSME), and both soil and foliar fertilizer (FNSSME) on leaf nitrogen (N) concentration, chlorophyll content, total potassium (K) in plant parts and starch content in the fresh roots, compared to a conventional, chemical fertilizer (CF) were studied in cassava cultivar ‘Hauybong 60’. The results showed that plants on FNSSME had the highest chlorophyll contents and SPAD values at four months after planting (MAP). Cassava plants treated with SSME and FNSSME had highest starch content and was significantly higher than in plants treated with CF and a FSME. There was a strong, positive relationship between the leaf nitrogen concentration and chlorophyll content in cassava at 6 MAP. The results of the study indicated that an application of FNSSME to cassava plants could provide a higher chlorophyll content and higher tuber quality of the plants than those applied with chemical fertilizer.