Alternative sources of nitrogen and phosphorus in potato fertilizer

Urea and diammonium phosphate were compared with ammonium nitrate and triple superphosphate, in all combinations, as sources of N and P in fertilizer on two soil types important in potato production in Ontario. Greenhouse experiments with these soils and a peat:vermiculite:sand mixture gave very varied root and shoot development which followed no constant pattern. The same combinations of fertilizer in the field gave no differences in emergence, appearance, or senescence, but there was one yield difference and minor, inconsistent differences in specific gravity and cooking quality.     

Bahiagrass response and N loss from selected N fertilizer sources

The increasing cost of commercial fertilizers and environmental problems associated with improper fertilization management have prompted the need to re‐examine commercial N sources that can effectively supply N to pastures while minimizing N losses. This 3‐year study evaluated the effects of selected N sources on bahiagrass (Paspalum notatum Flügge) responses, soil properties and N losses. Treatments consisted of a factorial combination of 6 N sources [(i) ammonium nitrate (AN), (ii) ammonium sulphate (AS), (iii) urea (U), (iv) urea treated with Agrotain (U + Agrotain), (v) SuperU and (vi) ammonium sulphate nitrate] and 3 N levels (0, 60 or 120 kg ha^?1 year^?1), replicated three times. Bahiagrass dry‐matter yield (DMY), crude protein (CP) concentration, N uptake and recovery were not affected by N source, with the exception of AN that resulted in reduced DMY in 2010 compared with the other sources. Bahiagrass DMY, CP concentration, N uptake and recovery increased linearly as N levels increased. Nitrogen fertilization showed no effect on soil pH or soil N accumulation. Soil pore‐water N concentrations from treatments fertilized with N were similar to the control plots indicating no threat to the environment. At the N levels evaluated in this study, selection of N source should be based on the fertilizer cost.     

不同N源对虎奶菇菌核产量与各类氨基酸含量的影响

运用灰色系统理论,探讨了不同氮源对虎奶菇菌核产量及其各类氨基酸总量的影响,并进行灰色关联的综合评判。结果表明:以麦皮为氮源的处理对虎奶菇菌核产量和品质的关联度最大,影响也最明显,添加不同氮源的处理对虎奶菇菌核及各类氨基酸含量的关联度大小顺序为:麦皮处理>牛粪处理>硫酸铵处理>尿素处理。     

氮磷钾配方施肥提升天然橡胶生胶性能

以8a生长的PR107橡胶树为研究对象,采用正交实验设计,研究氮、磷、钾肥配施对天然橡胶生胶性能及分子量的影响。结果表明:不同种类和水平的施肥处理对干胶含量有显著的影响,不同肥料对干胶含量最优施肥组合为尿素300 g/株、过磷酸钙250 g/株、氯化钾75 g/株;对生胶塑性初值的最优施肥组合为尿素0 g/株、过磷酸钙375 g/株、氯化钾25 g/株;对门尼黏度的最优施肥组合为尿素0 g/株、过磷酸钙250 g/株、氯化钾25 g/株;对生胶塑性保持率的最优施肥组合尿素200g/株、过磷酸钙375g/株、氯化钾50g/株。施肥对橡胶的分子量均有显著影响,对橡胶数均分子量(Mn)的最优施肥组合为尿素0g/株、过磷酸钙125g/株、氯化钾25g/株,对橡胶重均分子量(Mw)、黏均分子量(Mv)的最优组合施肥量为尿素300 g/株、过磷酸钙250 g/株、氯化钾25 g/株。在生产橡胶或胶乳制品时,可根据不同制品的需求选择合适的种植环境及施肥措施的橡胶树胶乳作为原材料,使制品性能达到最优。     

Fertilizer injury to potatoes as affected by fertilizer source,rate and placement

To investigate fertilizer injury to potatoes under field conditions, a three year study from 1979 to 1981 was undertaken in Central New York. The study was carried out on a well drained Howard gravelly silt loam; pH 6.6–6.8 with high organic matter (6.1–6.4%) and cation exchange capacity (CEC) of 13.4–14.9. When applied at a normal rate equivalent to 1,685 kg/ha of 10-15–15-1.2 the blended fertilizer containing urea N did not significantly reduce the tuber yield compared to ammoniated fertilizer and blended fertilizer containing ammonium nitrate (AN). However, when it was placed in contact with the seedpiece, the urea delayed emergence and early growth of the plant. Fertilizers containing urea-diammonium phosphate (DAP) and ureatriple superphosphate (TSP), applied at higher than normal rates and placed in contact with the seedpiece, significantly delayed emergence and reduced tuber yield.     

氮素供应形态对水稻根系形态和磷吸收的影响

 采用水培方法,研究了缺磷条件下不同形态氮（NH₄⁺、NO^₃-和NH₄NO₃）下的水稻根系形态性状,以及它们产生的后效应对磷吸收的影响。结果表明,在氮素供应充足但磷饥饿胁迫的状况下,氮素形态对根系的影响仍然十分显著。与单一的铵营养相比,铵硝混合营养增加了根长和根系的表面积、根系的密度以及磷的总吸收量;与单一的铵或硝营养相比,铵硝混合营养可增加吸收的磷从根系向地上部的运输。因此,铵硝混合营养改善低磷胁迫下水稻对磷的吸收和转运,其部分原因与氮素形态与根系形态发生有关。     

The Chemistry and Agronomic Effectiveness of Phosphate Fertilizers

Summary

Plants take up P from soil solution, so water-soluble P fertilizers are generally more effective than poorly soluble forms. The original sources of P used for agriculture were poorly soluble materials, including manures, bones, guano and phosphate rock. In contrast, highly soluble monocalcium phosphate, monoammonium phosphate and diammonium phosphate are the major compounds present in modern, manufactured solid fertilizers containing water-soluble P. This paper describes how the water-soluble P fertilizers are made, the dissolution of P in the granules of the fertilizers, the reactions of the fertilizer solution with the soil as P moves out of the granule into the soil, the agronomic effectiveness of the fertilizer in the year of application, and in the years after application (residual value).     

温度和供氮形态对龙眼吸收氮素动力学的影响

研究龙眼幼苗在不同温度（10、15、20、25、30、35℃）和不同氮营养（硝态氮、3/4硝态氮+1/4铵态氮、1/2硝态氮+1/2铵态氮、1/4硝态氮+3/4铵态氮、铵态氮）供应条件下吸收氮素的动力学特征,比较龙眼吸氮能力变化,并探讨龙眼对氮形态的偏好性,为龙眼不同季节（物候期）选择适用氮肥形态提供依据。结果显示,温度和供氮形态对龙眼吸氮能力有显著影响（P<0.05）。在中低温度（10~25℃）等量供应硝态氮和铵态氮条件下,龙眼根系吸收氮素（硝态氮和铵态氮之和）的最大吸收速率（I_max）最高或较高,而亲和力（Am）和离子吸收补偿点（C_min）则随温度和氮形态变化不大,故此时龙眼吸氮能力强。在高温（30℃）且仅供应铵态氮时,根系具有最高I_max和A_m,同时C_min最低,最有利于龙眼吸氮。在极端高温（35℃）时将铵态氮和硝态氮以3∶1的比例配合供应,则I_max最高,A_m较高且C_min较低,有利龙眼对氮素的吸收。另外,等量硝态氮和铵态氮共存条件下,龙眼在低温（10~15℃）时吸收铵态氮的I_max更高、A_m更强而且C_min更低,明显偏好铵态氮;在中高温（20~35℃）时吸收硝态氮的I_max更高,但A_m更弱且C_min更高,对氮形态的偏好性不明显。对照华南龙眼生长物候期,建议在龙眼秋梢生长期施用铵态氮为主、硝态氮为辅;在花前至小果期可以1∶1的比例施用硝态氮和铵态氮;在果实膨大期,可全部施用铵态氮或以3∶1的比例施入铵态氮和硝态氮。     

Nitrogen source evaluation for potato production on irrigated sandy soils

Ammonium sulfate (AS), ammonium nitrate (AN), urea (U), and calcium nitrate (CN) were evaluated as supplemental N sources for sprinkler irrigated potatoes on a loamy sand soil by determining N source effects on potato yield, quality, recovery of applied N in tubers, and petiole NO ₃ ^- concentration. At the N rate required to maximize yield (224 kg N/ha), 5-year average yields obtained with AS were significantly higher than those obtained using AN, U, or CN. Average total tuber yields with AS, AN, U, and CN were 59.3, 56.2, 56.5, and 54.8 Mg/ha, respectively. Yield differences between AS and AN or CN are likely due to greater N loss through leaching from the NO ₃ ^- -containing sources. This conclusion is supported by lower petiole NO ₃ ^- concentrations and lower recovery of applied N in tubers when AN or CN were used. Yield differences between AS and U suggest that N applied as U is more susceptible to loss than N applied as AS on the soil used in this work. The percentage of total tuber yield in the US1A quality category was not affected by N source, but the percentage of cull tubers was higher with AS than with AN or CN. Our results indicate that potato yield and N recovery can be improved by use of AS instead of U, AN, or CN for irrigated potato production on sandy soils. Potato yield, quality, and N recovery were similar when U or AN were used as supplemental N sources.     

The effects of rates of application and sources of nitrogen on nitrate concentration in oat forage

A field experiment was conducted during the winter seasons of 1972–73 and 1973–74 to study the effects of rates of application (0, 100, 200 kg ha^?1) and sources of nitrogen (ammonium sulphate, calcium ammonium nitrate, urea, sulphur-coated urea and sulpha-thiazole-treated urea) on nitrate-N concentration in oat (Avena sativa L.) forage. N application increased the nitrate-N concentration, the effects being more marked when the rate was increased from 100 to 200 kg ha^?1 than when it was raised from 0 to 100 kg ha^?1. The highest nitrate-N concentration in the dry matter (> 0·16%) was obtained when calcium ammonium nitrate was applied at 200 kg ha^?1 N. Sulphur-coated urea gave the lowest nitrate-N concentration. In one year treatment of urea with sulphathiazole reduced nitrate-N concentration in oats forage.     

Response of potatoes (cv russet burbank) to supplemental calcium applications under field conditions: Tuber calcium, yield, and incidence of internal brown spot

Potato tuber tissue is low in calcium as compared to leaves and stems. Several recent studies have provided evidence linking tuber quality with tuber tissue Ca concentration. The purpose of the present study was to determine the influence of supplemental Ca and N fertilization on tuber Ca concentration and internal brown spot of potato. Three soluble products (calcium nitrate, calcium chloride, and N-Plus; 9N:0K:0P:11Ca) were used as Ca sources with and without gypsum. In addition, a combination of calcium chloride, urea, and calcium nitrate (CUC) was also used without gypsum. Each treatment consisted of five replications, which received the same total amount of N (252 kg ha^?1) supplied either alone or in various combinations of ammonium nitrate, urea, calcium nitrate, calcium chloride, and N-Plus. The soluble sources of Ca were added at 68.8 to 168.0 kg ha^?1 while gypsum supplied Ca at 49 kg ha^?1. The application of all N by hilling (non-split) was compared to split application of N and Ca at hilling and 2, 4, and 6 wk after hilling. Tubers were mechanically harvested and graded according to industry standards. About 100 U.S. No. 1 tubers from each replication were cut in half along the longitudinal axis and visually inspected for internal defects. From each replication, non-periderm tissue from 15 tubers was combined for Ca analysis. There was no treatment effect on tuber yield in both years. Application of gypsum, either alone or in combination with the soluble sources, was not effective in reducing incidence of internal brown spot (IBS). Furthermore, with one exception, application of gypsum either alone or in combination with soluble sources of Ca was not effective at increasing tuber tissue Ca concentration. Combined analyses of data from 2 years showed that the application of soluble sources of Ca without gypsum increased tuber Ca concentration and decreased the incidence of IBS. Furthermore, split application of N had similar beneficial effects as compared to non-split N. Data from 1997 (a year with high IBS) gave a significant inverse relationship between tuber Ca and IBS, suggesting that an increase in tuber Ca can reduce IBS incidence.     

Factors Contributing to the Benefits of Foliar Nitrogen Application for Wheat in a Sub-Tropical Winter Environment

Abstract

Beneficial effects of foliar N application to cereal crops have been widely believed to rely on subsequent rainfall or irrigation in the semi-arid region where in-crop rain is insufficient and unreliable. To verify this, factors contributing to the effects of foliar N application were assessed by implementing foliar N application in trials on three farmers' properties in central Queensland, Australia. Solutions of CRN35 (30 kg N ha^?1 at 1.94 N % w v^_1), urea and UAN (both 26, 2.25%), and urea (20, 20%; 40, 20%) and UAN (20, 20%; 40, 40%), were applied to wheat at anthesis respectively at the three properties (sites). Adjuvant chemical agents were also applied in mixture form with the N at the latter two sites. At the first site, with foliar N (CRN35) application, grain protein content on average increased by 1.07 percentage points, and by 1.6 in the presence of basal superphosphate. Superphosphate alone also increased grain yield. At the second site, while the applications of UAN and urea increased grain protein content by 1.3 and 0.9 percentage points, respectively, UAN showed superiority to urea in N recovery.

At the third site, foliar N applications with or without chemical adjuvant did not affect grain protein content, but due to the higher concentration in the N solution, some of them (excluding UAN40) had negative effects on grain yield, compared to the water only control.

Based on our data and supporting literature, to ensure the positive effect on wheat grain protein content, subsequent irrigation or rainfall may not be critical provided that foliar N concentration is lower than 5%. It is also suggested that UAN is superior to urea as an N source for foliar application. For alkaline/sodic soils, while the application of basal superphosphate increased grain yield, the added foliar N ensured an increase of grain protein content.     

Impact of late-season N fertilisation strategies on the gluten content and composition of high protein wheat grown under humid Mediterranean conditions

The rise in high protein common wheat in humid Mediterranean areas has determined a need to compare specific and effective nitrogen (N) fertilisation protocols in order to increase their end-use value. The aim of the work was to assess the impact of late-season N fertilisation strategies on grain yield and protein content (GPC), gluten fraction composition, and rheological traits. Different applications and types of fertiliser (soil applied ammonium nitrate, soil applied urea, foliar applied urea and a foliar applied commercial fertiliser) were distributed at the same rate (30 kg N ha⁻¹) in a field experiment in NW Italy, during three growing seasons. A control without any late-season N fertilisation was also considered. All the treatments received 130 kg N ha⁻¹ as ammonium nitrate (AN), which was split between tillering and the beginning of the stem elongation growth stages.None of the compared late-season N fertilisations significantly affected canopy greenness and stay green duration during the grain filling period, or the grain yield, test weight, and thousand kernel weight, although the foliar application significantly increased foliage burning (+9.8%). The late application of N consistently increased GPC (+1.1%) and dough strength (W, +21%) in the different growing seasons. The type of fertilisation strategies clearly affected the gluten content and rheological parameters: AN was more effective than urea as a soil top-dressed applied fertiliser in increasing W (+10%), as a result of a higher rise in the GPC content (+0.5%) and extensibility (L, +11%). The foliar application at anthesis, at the same N rate, led to a comparable GPC and W with those of the soil top-dressed granular fertiliser. Only a weak effect of granular urea on y/x type HMW was observed for the gluten composition. Conversely, a notable influence of year was observed (i.e. GS/Glia and y/x type HMW), which in turn resulted in a significant impact on W and P and on the aggregation time and aggregation energy.This study offers a further contribution to the improvement of specific N fertilisation strategies in order to enhance the wheat quality according to its end-use value.     

Fumigation and Fertilizer Nitrogen Source Effects on Potato Yield,Quality, and Early Dying

Research has shown that while fumigation and use of ammonium N can both reduce the severity of verticillium wilt (Verticillium dahliae Kleb.) of potatoes (Solanum tuberosum L.), the use of the two practices together raises concerns over feeding the crop only ammonium N under reduced nitrification conditions. To assess the validity of this concern, we conducted two 3-year field split-plot experiments with both using metam sodium fumigant (none, fall or spring applied) as the main plot. For the first experiment, N source (134 kg N ha^?1 as ammonium sulfate, urea, or ammonium nitrate) was the split, whereas for the second trial in-season N rate (0, 67, 134, or 202 kg N ha^?1 all as ammonium sulfate) was the split. For both trials, in 2 of the 3 years, fumigation significantly increased tuber yield by an average of 9.9 Mg ha^?1 and decreased late-season verticillium severity ratings from 77 to 45%. In some years, fumigation also increased the proportion of U.S. No. 1 tubers and tubers >170 g. No differences in crop yield or quality were observed between the various N sources applied. This was true even on spring-fumigated areas with the highest rate of ammonium N applied. These experiments confirm that the choice between in-season potato N fertilizer should be based on factors such as potential for benefits or N losses, cost, and convenience of use rather than concern over an interaction between fumigation and ammonical N. While both fumigation and N rate reduced verticillium severity ratings in some years, the lack of interaction suggests these factors are functioning independently.     

Influence of Organic and Inorganic Nitrogen on Grain Yield and Yield Components of Hybrid Rice in Northwestern Pakistan

Field experiments were conducted to assess the impact of various organic sources, inorganic nitrogen(N) and the different combinations of inorganic N(urea) + organic source on the yield components(YC) and grain yield(GY) of hybrid rice(Oryza sativa L., Pukhraj) under rice-wheat system. The experiments were conducted at Batkhela(Malakand), Northwestern Pakistan, in 2011 and 2012. Our results revealed that YC and GY ranked first for the hybrid rice when applied with sole inorganic N(urea), followed by the application of N in mixture(urea + organic sources), while the control plots(no N applied) ranked in the bottom. Among the six organic sources(three animal manures: poultry, sheep and cattle; three crop residues: onion, berseem and wheat), application of N in the form of poultry manure was superior in terms of higher YC and GY. When applying 120 kg/hm2 N source, 75% N from urea + 25% N from organic source resulted in higher YC and GY in 2011, while applying 50% N from urea + 50% N from organic sources caused higher YC and GY in 2012. Therefore, the combined application of N sources in the form of urea + organic source can produce good performances in terms of higher YC and GY of rice under rice-wheat cropping system.     

淹涝胁迫和氮形态对苗期玉米营养特性的影响

采用砂培培养方法,比较研究两种水分条件和3种供氮形态处理对苗期玉米根、茎鞘、叶生物量干重及其氮、磷、钾含量及分配的影响。结果表明,非淹涝胁迫条件下铵硝态氮混合处理(AN)玉米生物量干重及氮、磷、钾累积量最高;淹涝胁迫条件下铵硝态氮混合处理(ANF)的叶片、总生物量以及硝态氮处理(NF)的根系、叶片和总生物量干重明显降低。淹涝胁迫降低3种氮形态处理叶片氮累积量,明显降低铵硝态氮混合处理和硝态氮处理植株氮、钾累积量,降低磷在铵硝态氮混合处理茎鞘、叶中的分配比例、磷在硝态氮处理根、叶中的分配比例以及钾在铵硝态氮混合处理茎鞘、叶中的分配比例。淹涝胁迫下铵态氮处理(AF)叶片含氮量、植株含钾量呈降低趋势;非淹涝胁迫下铵态氮处理(A)具有相对较高的植株氮、磷含量,且淹涝胁迫对氮、磷、钾在植株不同部位分配的影响相对较低。因此,本试验供应铵态氮苗期玉米具有相对较强的耐淹涝胁迫能力。     

黄棕壤和酸紫砂土施用不同磷肥对油菜产量的影响

为实现油菜磷肥减施增效和保障生态环境,利用土壤有效磷含量较低的黄棕壤和酸紫砂土开展试验,建立土壤-磷肥-作物体系相匹配的磷肥施肥方案.以甘蓝型油菜中双11号和圣光168为材料,采用盆栽试验研究黄棕壤和酸紫砂土上施用过磷酸钙(SSP)、磷酸二铵(DAP)、聚磷酸铵(APP)和钙镁磷肥(CMP)对油菜苗期生长及成熟期产量、...     

A comparison of nitrogen fertilizers for spring and summer grass production

Three experiments were carried out in 1983-85 to compare split dressings of ammonium nitrate and urea with a single injection of aqueous ammonia for seasonal and total annual dry matter (DM) production. Total annual fertilizer nitrogen (N) applied was 360 kg ha¹ for a six-cut management. The solid fertilizers were applied in spring at different dates for the first cut and then after cuts 1 —4in the pattern 90,90,60,60,60 kg N ha¹. A winter injection of aqueous ammonia in the first year was replaced thereafter by early and late spring injections, the latter at 300 kg N ha¹ with 60 kg N ha ¹ as ammonium nitrate. Injection was to a depth of 100 mm at 30 cm spacing using a commercial applicator. The experiments were carried out on farms in a low rainfall area; the soils were sandy loams. Urea gave 3% less total DM production than ammonium nitrate (0middot;32±0middot;153 t ha-¹) and produced on average 7% less DM in the spring, and 12% less in dry conditions in early autumn of 1984. Lower production was associated with reduced uptake of N, which occurred at most cuts. From these experiments it is concluded that urea can be a suitable alternative to ammonium nitrate, and when used in spring must be about 20% cheaper per kg N. The performance of aqueous ammonia was variable. In the dry summer of 1984, when applied in early April with 60 kg N ha-¹ as ammonium nitrate it equalled the ammonium nitrate treatment in both spring and total production and was better (P< 0 ?05) in early autumn. In the same year, an early March injection was inferior (P < 0 05) in total DM production to ammonium nitrate. This early injection was also lower, but not significantly (P>005) in 1985, mainly because of lower spring production. A delayed, mid-April injection, plus ammonium nitrate, in 1985, gave even less spring growth and lower total production. A January injection, in 1983, showed poor persistency and is not recommended for sandy loam soils.     

滴灌施氮对赤红壤酸化的影响

通过盆栽试验研究滴施不同品种氮肥对赤红壤酸化过程的影响.结果表明,在滴施硫酸铵、硝酸铵和尿素的条件下,各个土层的pH值都有所降低,同时,土壤的交换性铝含量有一定程度的增加;种植玉米的处理在滴头正下方各个土层的pH值均高于不种植玉米的处理,而交换性铝含量则低于不种植玉米的处理.种植玉米能够缓解滴施氮肥后的土壤酸化,降低土壤交换性铝含量.     

Utilization of cassava peels as substrate for crude protein formation

Mash prepared from cassava peels was inoculated with eitherSacchromyces cerevisiae orCandida tropicalis and then left to ferment for 7 days. Chemical analysis of the fermented mash showed substantial increase in crude protein content and decrease in carbohydrate content of the mash. The results also revealed slight increases in the ash, fibre and lipid content of the fermented mash. It was further observed that, when the mash was supplemented with inorganic nitrogen sources (urea, ammonium sulfate or sodium nitrate) before commencement of fermentation, the amount of crude protein formed was almost doubled. This enhanced crude protein production was highest in the mash supplemented with urea. Temperature of 30 °C, pH of 5.5 and moisture concentration of 130% were found to be optimum for crude protein formation by the organisms growing on the mash.