不同施氮水平对春玉米氮素吸收、转运及产量的影响

采用田间试验研究吉林省中部玉米主产区不同氮水平对玉米产量、氮素吸收、转运及氮肥利用率的影响。结果表明,施用氮肥可以提高干物质最大积累速率和氮素最大吸收速率,并能提前干物质最大积累速率和氮素最大吸收速率出现的天数。在施N 60~180 kg/hm2之间,玉米产量、干物质最大积累速率、氮素最大吸收速率、转运量、转运率及子粒中养分比例等指标均有显著提高;超过N180 kg/hm2,干物质最大积累速率、氮素最大吸收速率、转运量、转运率及子粒中养分比例等指标开始下降。根据玉米产量(y)和施氮量(x)拟合得出,最高产量氮肥用量为184.2 kg/hm2,最佳经济产量氮肥用量为172.9 kg/hm2。氮素农学利用率、氮肥当季回收率及偏生产力随着氮肥用量的提高而显著降低。综合考虑提高玉米产量、效益和氮肥利用效率等方面的要求,在吉林省中部玉米主产区,适宜施氮量为172.9 kg/hm2。     

不同氮肥模式对夏玉米产量、蛋白质品质和氮素利用特性的影响

以高产玉米品种郑单958和先玉335为供试材料,在大田生产条件下设置4个施氮水平,研究不同氮肥模式对两个高产玉米品种子粒产量、蛋白质产量及氮素利用特性的影响。结果表明,两个玉米品种子粒产量随施氮量的增加显著增加,均以240 kg/hm~2处理最高,先玉335子粒产量显著高于郑单958;两个玉米品种子粒蛋白质含量及其产量随施氮量的增加显著增加,先玉335的蛋白质含量及其产量均高于郑单958;两个玉米品种氮素利用效率、氮肥生产效率和氮肥农学利用效率随施氮量的增加而显著降低,均以180 kg/hm2处理最高,先玉335的氮素利用效率、氮肥生产效率和氮肥农学利用效率均高于郑单958。综合分析认为,两个玉米品种均以240 kg/hm~2处理可以同步协调实现较高的子粒产量、蛋白质含量和氮素利用效率,获得产量、品质和高氮素利用效率的协调统一。     

氮肥减施对京科968与郑单958氮效率及产量的影响

以郑单958与京科968为材料,在减施氮肥(正常施氮量210 kg/hm~2)14.3%~28.6%水平下,比较玉米品种氮效率与产量。结果表明,施氮肥150~180 kg/hm2,郑单958产量下降2.39%~4.03%,京科968产量下降1.67%~2.99%。随着施氮量减少,氮肥偏生产力、氮肥利用效率,氮肥农学利用效率升高,氮肥表观利用效率、100 kg子粒需氮量降低,氮收获指数保持基本稳定。适度减施氮肥,可有效提高玉米生产效率。施氮处理下不同器官的氮转运率与对子粒的氮贡献率高于不施氮处理,不同器官的氮转运率顺序为穗轴叶片苞叶叶鞘茎秆;对子粒的氮贡献率表现为叶片茎秆穗轴叶鞘苞叶。京科968氮收获指数、氮肥偏生产力、氮肥表观利用效率均优于郑单958,氮肥农学利用效率、氮肥利用效率与子粒吸氮量与郑单958相当。京科968氮吸收效率优于郑单958,具备较好的耐低氮特性。     

普通玉米和O2玉米自交系间杂交种子粒赖氨酸含量及子粒性状的分析

用普通玉米自交系和O2玉米自交系进行双列杂交,对普通玉米×O2玉米(普×O2)、普通玉米×普通玉米(普×普)和O2玉米×O2玉米(O2×O2)三种类型杂交组合F1的子粒赖氨酸含量、产量、赖氨酸产量、容重、收获时子粒含水量进行了比较分析。结果表明:普×O2组合的赖氨酸含量介于普×普和O2×O2之间,但变化幅度较大;产量和粒重最高,容重和收获时子粒含水量介于两者之间偏近于普×普,赖氨酸产量和O2×O2接近。认为以普通玉米与O2玉米自交系组配杂交种是一种值得探讨的高赖氨酸玉米选育方法。     

东北和西北春玉米氮磷钾养分吸收、积累特点比较

通过东北(吉林公主岭,JL-GZL)和西北(新疆伊犁71团,XJ-71)两个生态条件差异明显的大田试验,比较不同生态区春玉米植株养分吸收、积累差异。研究表明,西北试点的春玉米子粒产量、干物质积累量、氮磷钾等养分积累量均高于东北试点,其中,子粒产量、干物质积累量达极显著水平,叶片、茎秆、子粒氮、磷、钾养分积累量均达显著水平。东北春玉米叶片、茎秆氮含量较西北春玉米高,叶片、茎秆磷含量无显著差异,叶片、茎秆钾含量在整个生育期低于西北春玉米。西北春玉米每吸收1 kg氮所产生的子粒、干物质分别较东北春玉米高7.75%、7.11%,每吸收1 kg钾所产生的子粒、干物质分别较东北春玉米低9.12%、9.71%,每吸收1 kg磷所产生的子粒、干物质两个生态区无显著差异。氮磷钾收获指数与养分利用效率的变化趋势相同,西北试点氮收获指数高于东北试点,钾收获指数低于东北试点,磷收获指数无显著差异。     

氮钾配比对寒地玉米干物质积累、产量及品质的影响

通过田间小区试验,研究不同氮钾配比对玉米不同生育期和不同器官的干物质积累、分配、运转和产量及对品质的影响。结果表明,施氮量为150 kg/hm2、施钾量为100 kg/hm2的处理在成熟期茎、叶、穗干物质量、阶段子粒干物质积累量、茎部转运量、转运率、贡献率以及玉米子粒产量、子粒蛋白质与淀粉含量均高于其他处理。因此,氮、钾肥施用量为150 kg/hm2和100 kg/hm2有利于寒地玉米的干物质积累、产量及其品质的提高。     

吉林省黑土区玉米氮肥减施效果研究

针对目前吉林省黑土区玉米种植过程中氮肥用量偏高导致的氮肥利用率低、氮素残留高等问题,在习惯施氮量的基础上设降低10%、20%、30%、40%的不同氮肥减量处理,研究减氮对春玉米干物质积累、子粒产量、氮素利用效率及土壤中无机氮积累的影响。结果表明,伏龙泉和米沙子试验点降低20%氮肥用量、开安试验点降低30%氮肥用量玉米子粒产量无显著降低,减氮处理显著提高氮肥的利用效率。降低氮肥用量可减少玉米收获后耕层土壤中无机氮的积累(硝态氮)。玉米施氮量在223 kg/hm2时玉米收获后耕层土壤无机氮含量与播种前基本一致。吉林省黑土玉米种植区适当降低氮肥用量不会显著影响玉米产量,同时会提高氮肥利用效率,减少玉米收获后耕层无机氮的积累。     

水氮胁迫对玉米产量和氮素吸收和运移的影响

2011~2012年在吉林公主岭试验区可移动防雨棚内进行两年微区试验,探讨水氮胁迫对玉米产量及氮素的吸收和分配的影响。结果表明,全生育期灌水300 mm情况下,玉米产量随施氮量的增加而增加;水分胁迫(灌水100 mm)情况下,玉米产量随施氮量的增加而减少。植株氮积累总量成熟期最高,氮素在营养器官中的比例最高时期是拔节期,生殖器官含氮比例最高在吐丝期,子粒的含氮百分比最高时期是吐丝后15 d。水氮胁迫条件下,氮素转运率、贡献率均下降,仅氮胁迫转运率和贡献率增加。相同灌水量情况下,子粒吸收氮素量与施氮量显著正相关;水分胁迫条件下,表观土壤水分利用效率随施氮量的增加而下降,正常供水则相反;水分胁迫下的土壤水分利用效率极显著高于正常供水。     

转植酸酶基因（phyA2）玉米磷素营养的初步研究

在大田栽培条件下研究3种转phyA2基因玉米C63、C83-1-7和C84-1-14对土壤有机磷的利用能力及玉米磷素营养状况。初步结果表明,转phyA2基因玉米能有效利用土壤有机磷,与阴性对照相比,转phyA2基因玉米生长发育状况更好,磷素积累量更多,可获得更高的生物量和子粒产量,转基因玉米C63、C83-1-7和C84-1-14单株磷积累量分别是阴性对照的7.8倍、1.6倍和2.5倍,单株子粒产量分别是阴性对照的5.5倍、1.5倍和2.1倍。在大田栽培条件下转phyA2基因玉米生长状况好于阴性对照。     

施钾对春玉米产量、养分吸收及分配的影响

通过连续两年田间试验,研究吉林省中部玉米主产区施钾对春玉米产量、养分吸收、转运、分配及钾肥利用率的影响。结果表明,施用钾肥可显著提高春玉米产量,在一定施钾范围内,春玉米产量随施钾量的增加而增加,当施钾量超过90 kg/hm2后产量不再增加,根据玉米产量(y)和施钾量(x)拟合,得出最佳施钾量为82.9~86.6 kg/hm2。施钾肥可提高干物质最大积累速率和积累总量、养分最大吸收速率和吸收总量,提前干物质最大积累速率和养分最大吸收速率出现的时间。施钾可提高春玉米氮、磷、钾养分向子粒的转运量及转运率,施钾量30~90 kg/hm2范围内抽雄期养分积累量与子粒转运量和转运率呈正比,当施钾量超过90 kg/hm2后,氮、磷、钾养分转运出现负效应。钾素农学利用率和偏生产力随着施钾量的增加而下降,钾肥当季回收率以施钾量90 kg/hm2处理最高。在吉林省中部玉米主产区,适宜施钾量为82.9~86.6 kg/hm2。     

Improving Yield and Quality of Processing Potato Crops Grown in the Argentinian Pampas: the Role of N,P and S and Their Impact on CO<Subscript>2</Subscript> Emissions

The area grown with processing potato crops in the Argentinian Pampas has been increasing steadily since 1995. The aim of this work was to assess the effects of N, P and S upon yield and tuber quality and their impact on CO₂ emissions assessed with the Cool Farm Tool-Potato. During the spring-summer growing seasons 2008/2009 and 2009/2010, ten fertilization experiments to individually assess N, P and S effects were carried out in the southeast region of the Argentinian Pampas. Nitrogen (four N rates), phosphorus (four P rates) and sulfur (three S rates) were applied at planting and tuber initiation; at combined rates of 0, 50, 100 and 150 kg N ha^?1, and at rates of 0, 25, 50 and 100 kg P ha^?1 and 0, 10 and 20 kg S ha^?1. N and P had a positive effect on total tuber yield, but tuber dry matter concentration (DMC) decreased at higher N rates. The fraction of marketable tubers suitable for processing into French fries increased with the addition of N, showed no variations with P fertilization, and decreased when S was applied. French fry colour, length/width (L:W) ratio and tuber defects were not affected by N, P and S fertilization. With regard to CO₂ emissions assessed with the Cool Farm Tool-Potato, results showed that the higher the N rates the higher the CO₂ emissions, but they decreased at higher yields. P and S rates did not have an impact on the CO₂ emissions, which also decreased at higher yields. Under the production system of the Pampas, N should be split between planting and tuber initiation, and intermediate P rates should be applied all at planting, in order to improve crop yield and quality and to reduce CO₂ emissions.     

氮磷钾配比对高产夏玉米产量、养分吸收积累的影响

通过大田试验研究了高产夏玉米土壤养分限制因素及植株养分吸收积累规律。结果表明：各施肥处理均比不施肥显著增产,增产7.3%～15.9%,氮磷钾推荐施肥(OPT)处理产量最高,达到12 051.2 kg/hm²,增产1 651.2 kg/hm²;施用氮肥、钾肥能显著提高夏玉米的产量,N、K是高产夏玉米主要养分限制因素。高产夏玉米植株体内氮、磷、钾的积累量均随生育期的延长而增加,养分积累量的大小顺序为N>K>P,从拔节期至大喇叭口期是氮素、磷素和钾素吸收量和吸收速率最大的时期,整个生育期,高产夏玉米能持续吸收N、P、K养分。N当季回收率为18.05%,P₂O₅为14.55%,K₂O为18.34%,每生产100 kg经济产量需吸收的N、P₂O₅、K₂O的量分别为1.62、0.69、1.83 kg。     

Effect of the type of fertilizer and source of irrigation water on N use in a maize crop

An experiment in a maize crop evaluated the influence of several types of commercial nitrogenous fertilizers with different action mechanisms — urea (soluble), Floranid-32 (low water solubility) and Multicote 4 (coated fertilizer) — on maize grain and biomass yields, as well as on plant N use. The fertilizers were applied as a top-dressing of 294 kg N ha⁻¹. All treatments additionally received 64 kg N ha⁻¹ as 8.0 (N):6.5 (P):12.5 (K) compound prior to seedbed preparation. The influence of NO⁻₃ content in the irrigation water was also assessed, using water with either 2.5 or 35 mg l⁻¹ of NO⁻₃. Irrigation plus rainfall totalled 513 mm (1.20 potential ET). Nitrogen lost during the cultivation period was calculated from the N balance of the topsoil.Results obtained under these experimental conditions showed that the type of fertilizer did not alter maize grain and biomass yields. Yields for maize irrigated with the higher NO⁻₃ water were systematically greater than those obtained with irrigation water of low NO⁻₃ content.Nitrogen lost from the topsoil during the cultivation period varied between 240 and 280 kg N ha⁻¹ for all treatments, and was well correlated with NO⁻₃-N leached into the aquifer during the same period.     

Comparison of integrated field programmes for the reduction of fumonisin contamination in maize kernels

Fusarium verticillioides is a common maize pathogen which causes diseases on ears and synthesis of the mycotoxins, fumonisins, in kernels. Fumonisin production is influenced by both environmental conditions and agricultural inputs during growth and maturation of the maize plant. The aim of this research was to evaluate the effect of crop management techniques on fumonisin contamination in maize kernels. Experiments were conducted in Northern Italy during 2006 and 2007 using two maize hybrids with different precocity. Factors evaluated were seed planting time (March versus May), plant density (65,000 plants versus 80,000 plants per ha), N fertilization (200 kg N versus 400 kg N per ha), and chemical treatment to control European maize borer (ECB) (yes versus no). These factors were analyzed were as follows: (T1) May sowing, high plant density and N fertilization, (T2) March sowing time, high plant density and N fertilization, (T3) March sowing time, low plant density and balanced N fertilization, (T4) the same agronomic techniques as T3 plus a chemical treatment to control European maize borer. Ears were analyzed morphologically for ECB incidence and severity. Subsequently, kernels were analyzed chemically for fumonisins. Fumonisin contamination was reduced by 57%, 69% and 86% for T2, T3 and T4, respectively, compared to T1. This study clearly underlines that the application of good agricultural practices (GAP) in crop management strategies can effectively control fumonisin contamination of maize kernels.     

Nitrogen uptake,fixation and response to fertilizer N in soybeans: A review

Although relationships among soybean (Glycine max [L.] Merr) seed yield, nitrogen (N) uptake, biological N₂ fixation (BNF), and response to N fertilization have received considerable coverage in the scientific literature, a comprehensive summary and interpretation of these interactions with specific emphasis on high yield environments is lacking. Six hundred and thirty-seven data sets (site–year–treatment combinations) were analyzed from field studies that had examined these variables and had been published in refereed journals from 1966 to 2006. A mean linear increase of 0.013 Mg soybean seed yield per kg increase in N accumulation in aboveground biomass was evident in these data. The lower (maximum N accumulation) and upper (maximum N dilution) boundaries for this relationship had slopes of 0.0064 and 0.0188 Mg grain kg⁻¹ N, respectively. On an average, 50–60% of soybean N demand was met by biological N₂ fixation. In most situations the amount of N fixed was not sufficient to replace N export from the field in harvested seed. The partial N balance (fixed N in aboveground biomass − N in seeds) was negative in 80% of all data sets, with a mean net soil N mining of −40 kg N ha⁻¹. However, when an average estimated belowground N contribution of 24% of total plant N was included, the average N balance was close to neutral (−4 kg N ha⁻¹). The gap between crop N uptake and N supplied by BNF tended to increase at higher seed yields for which the associated crop N demand is higher. Soybean yield was more likely to respond to N fertilization in high-yield (>4.5 Mg ha⁻¹) environments. A negative exponential relationship was observed between N fertilizer rate and N₂ fixation when N was applied on the surface or incorporated in the topmost soil layers. Deep placement of slow-release fertilizer below the nodulation zone, or late N applications during reproductive stages, may be promising alternatives for achieving a yield response to N fertilization in high-yielding environments. The results from many N fertilization studies are often confounded by insufficiently optimized BNF or other management factors that may have precluded achieving BNF-mediated yields near the yield potential ceiling. More studies will be needed to fully understand the extent to which the N requirements of soybean grown at potential yields levels can be met by optimizing BNF alone as opposed to supplementing BNF with applied N. Such optimization will require evaluating new inoculant technologies, greater temporal precision in crop and soil management, and most importantly, detailed measurements of the contributions of soil N, BNF, and the efficiency of fertilizer N uptake throughout the crop cycle. Such information is required to develop more reliable guidelines for managing both BNF and fertilizer N in high-yielding environments, and also to improve soybean simulation models.     

Yield,market quality and petiole nitrate concentration of non-irrigated Russet Burbank and Shepody potatoes in response to sidedressed nitrogen

Russet Burbank and Shepody potatoes were grown with the following four nitrogen treatments: 1) 90 kg ha^?1 at planting; 2) 180 kg ha^?1 at planting; 3) 90 kg ha^?1 at planting followed by an additional 90 kg ha^?1 side-dressed after tuber initiation; or 4) 90 kg ha^?1 at planting followed by an additional 45 kg ha^?1 sidedressing. When compared to the 90 kg ha^?1 at-planting treatment, petiole NO₃-N concentrations increased rapidly after sidedressing and were relatively constant through mid-season. Sidedressed N significantly increased total yields relative to the 90 kg N ha^?1 at-planting treatment by an average of 5.0 t ha^?1 in three of nine experiments. Three of the experiments, where yields did not significantly increase, were on sites which were not expected to respond to supplemental N based on petiole NO₃-N testing. A red clover green manure crop was the previous crop for two of these experimental sites. Petiole NO₃-N testing criteria were only partially effective in detecting sites where response to sidedressed N occurred. When compared to a single application of 180 kg N ha^?1 at planting, split application of 90 kg N ha^?1 at planting followed by a 90 kg N ha^?1 sidedressing significantly reduced total yields in one of nine experiments and did not affect yields in the remaining eight experiments. Tuber uniformity was improved in three of nine experiments by the split-N treatment. Specific gravity was not significantly affected. Use of 45 kg N ha^?1 at side-dressing resulted in similar yield as the 90 kg N ha^?1 sidedressing, although yield of large-sized tubers was often decreased with the lower N rate. Use of reduced at-planting N rates followed by sidedressed N does not appear to increase yields of non-irrigated Russet Burbank and Shepody potatoes when compared to the at-planting N rates that are currently recommended. This management approach can maintain yields at levels comparable to at-planting N programs and does provide an opportunity to reduce N application rates on sites where soil N reserves and soil amendments may make a substantial N contribution to the potato crop. Side-dressed N application can frequently improve yields and tuber size when potatoes have been underfertilized at planting; however, some inconsistency in response can be expected in regions that rely on unpredictable natural rainfall.     

山西省北部地区玉米化肥施用现状——基于应县大黄巍乡玉米种植户施肥状况调研

通过系统分析山西省朔州市应县玉米种植户化肥投入现状发现,农户的玉米平均产量为10.3 t/hm~2,平均施肥总量为465 kg/hm~2,氮、磷、钾肥的用量分别为262、123、84 kg/hm~2,氮、磷、钾偏生产力分别为42、69、135 kg/kg。基于土壤养分测试,该地区推荐的氮、磷、钾施肥量分别为225、90、45 kg/hm~2。与推荐施肥量相比,氮、磷、钾肥施用过量农户的比例分别为75%、81%和93%。过量的养分投入并没有显著增加玉米产量。     

Effects of N application on agronomic and environmental parameters in silage maize production on sandy soils

The current nitrogen (N) use in silage maize production can lead to considerable N losses to the environment. Maize growers fear that a reduction of N inputs needed to minimize N losses might depress yields. The objective of this study was therefore to quantify: (1) the response of silage maize dry matter (DM) yields to N, (2) the economically optimal N reserve, and (3) the trade-off between silage maize DM yield and N losses. The indicators of N losses used in this study were the difference between N input and N uptake and the post-harvest residual soil mineral N. Regression models were used to fit DM yields and N uptakes of silage maize measured in 25 experiments on sandy soils in the Netherlands to the sum (SUMN) of the soil mineral N reserve (SMN_early) in March–April, plus mineral N in fertilizer, plus ammonium N in spring-applied slurry. The values obtained for the economically optimal SUMN in the upper 30 and 60 cm of soil were, respectively, 173 and 195 kg N ha⁻¹, when we assumed that the value of 1 kg fertilizer N equals the value of 5 kg silage DM. The economically optimal SUMN was not significantly related to the attainable DM yield. The apparent N recovery (ANR) of maize averaged 53% at the economically optimal SUMN. The ANR rose considerably, however, when N was applied at lower rates, indicating that N losses may be considerably smaller in less intensive maize cropping. When maize was fertilized at 100 kg N ha⁻¹ below the economic optimum, the ANR was 73%, the difference between the mineral N input and the N crop uptake decreased by 57 kg N ha⁻¹ and the soil mineral N residue at the end of the growing season (0–60 cm) decreased by 24 kg N ha⁻¹. The associated reduction in DM yield averaged 16%. Fertilizer prices would have to be as much as four times higher to make maize growers spontaneously reduce the application rates by a 100 kg N ha⁻¹, however. It is concluded that adjusting the N input to a level below the economically optimal rate can reduce the risks for N losses to the environment associated with conventional maize production, with a limited effect on silage yields.     

Elevated atmospheric CO2 effects on N fertilization in grain sorghum and soybean

Increasing atmospheric CO₂ concentration has led to concerns about global changes to the environment. One area of global change that has not been fully addressed is the effect of elevated atmospheric CO₂ on agriculture production inputs. Elevated CO₂ concentration alterations of plant growth and C:N ratios may modify C and N cycling in soil and N fertility. This study was conducted to examine the effects of legume, soybean (Glycine max (L.) Merr.), and non-legume, grain sorghum (Sorghum bicolor (L.) Moench.) carbon dioxide-enriched agro-ecosystems on N soil fertility in a Blanton loamy sand (loamy siliceous, thermic, Grossarenic Paleudults). The study was a split-plot design replicated three times with crop species (soybean and grain sorghum) as the main plots and CO₂ concentration (ambient and twice ambient) as subplots using open top field chambers. Fertilizer application was made with ${}^{15}\text{N}$-depleted NH₄NO₃ to act as a fertilizer tracer. Elevated CO₂ increased total biomass production in all 3 years of both grain sorghum (average 30%) and soybean (average 40%). With soybean, while no impact on the plant C:N ratio was observed, the total N content was greatly increased (average 29%) due to increased atmospheric N₂ fixation with elevated CO₂ concentration. With grain sorghum, the total N uptake was not affected, but the C:N ratio was markedly increased (average 31%) by elevated CO₂. No impact of elevated CO₂ level was observed for fertilizer N in grain sorghum. The results from this study indicated that while elevated CO₂ may enhance crop production and change N status in plant tissue, changes to soil N fertilizer application practices may not be needed.     

玉米和小麦间作农田水分动态变化的研究

本文讨论了清种玉米、清种小麦、玉米和小麦间种比例分别为4∶1、3∶1和2∶2农田的水分动态变化.结果表明,由于小麦和玉米的强烈竞争和相互影响使作物的农田水分动态变化和作物耗水量产生变异,以及受时空分布差异的影响,最终导致不同处理的作物产量和水分利用效率出现明显差异.其中3∶1间种具有较好的综合效果.小麦产量达到2707.2kg/hm²,玉米产量达到11191.5kg/hm²,而清种小麦和清种玉米的产量分别为2355kg/hm²和10153.5kg/hm².