Aspects of nitrogen fertilizer rate on tuber dry-matter content of potato cv. Record

Summary Effects of three rates of fertilizer nitrogen, viz. 80, 160 and 240 kg N/ha, on tuber yield and dry-matter percentage in potato cv. Record were compared in two experiments. Crop nitrogen uptake increased with application rate but total uptake differed between experiments. Tuber yield was highest following application of 160 or 240 kg N/ha but differences between these two rates were not significant. Tuber dry-matter percentage was reduced in one experiment with increasing nitrogen rate, but in the second experiment final dry- matter percentage was highest following application of 240 kg N/ha. In all treatments, positive linear relationships were found between dry matter percentage and mean fresh weight of tubers >30 mm, but within experiments, the regression coefficients were generally reduced by increased crop nitrogen uptake.     

密度对高产夏玉米产量和氮素利用效率的影响

选用登海661和超试11为试验材料,研究种植密度对高产夏玉米产量和氮素利用率的影响。结果表明,随密度的增加产量先增加后降低,登海661在密度为12万株/hm2时产量最高,为11 292 kg/hm2;氮肥偏生产力随密度的增加先升高后降低,在密度为12万株/hm2时达最大,为37.64 kg/kg;总氮素积累量在3.0万～10.5万株/hm2范围内先增加后降低,进一步增加种植密度后总氮素积累量增加;低密度条件下氮素利用率较高,随密度升高呈降低趋势;氮素收获指数随密度增加先增加后降低,在12万株/hm2时达最大值。本试验条件下,获得较高产量和氮素利用效率的适宜种植密度为7.5万～10.5万株/hm2。     

Potato response to split nitrogen timing with varying amounts of excessive irrigation

Irrigation and nitrogen management are two of the most important factors affecting production efficiency and environmental quality in potato cropping systems. Field studies were conducted in 1990 and 1991 to determine the interactive effects of irrigation amount and N timing on potato yield, quality and nitrate leaching potential. Sprinkler irrigation was applied at approximately 1.0, 1.2 or 1.4 times estimated evapotranspiration (ET) to Russet Burbank potatoes grown on a silt loam soil. Following tuber initiation, a total of 132 kg N/ha was applied through the irrigation system to N treatment subplots using either six weekly 22 kg N/ha applications or 3 biweekly 44 kg N/ha applications. Excessive irrigation reduced root zone and petiole NO₃-N concentrations during substantial portions of the tuber bulking period. Biweekly 44 kg N/ha applications in 1991 produced higher and more consistent earlyseason root zone NO₃-N concentrations in the 1.2 and 1.4 ET plots than did the weekly 22 kg N/ha applications. Late-season tuber dry weight, total plant dry weight and plant N uptake were not affected by irrigation rate or N timing. However, excessive irrigation reduced U.S. No. 1 yield and yield of tubers >284 g in both 1990 and 1991 and reduced total yield in 1990. Biweekly N applications produced higher U.S. No. 1 yields than weekly N applications at all irrigation levels. Excessive irrigation also reduced NO₃-N remaining in the top 60 cm of soil at the end of the growing season. These results show that irrigating at optimal rates and applying split N at two week intervals on a silt loam soil can maximize Russet Burbank yield and quality while minimizing NO₃-N losses.     

Effect of seedpiece spacing and nitrogen fertilization on tuber yield, yield components, and nitrogen use efficiency parameters of two potato cultivars

The effect of seedpiece spacing on the efficiency of nitrogen (N) use by the potato crop is generally unknown. The objective of this experiment was to determine the effect of seedpiece spacing on tuber yield, yield components and N use efficiency parameters of two potato cultivars. Potato cultivars Atlantic and Shepody were grown at two rates of N fertilization (0 or 100 kg N ha^?1) and three seedpiece spacings (20, 30, or 40 cm) in 2000 to 2002. Wider seedpiece spacing increased mean tuber weight and the number of tubers per stem, but decreased total tuber yield. The higher tuber yield at the narrow seedpiece spacing was attributed to higher biomass production in combination with lower tuber specific gravity. Seedpiece spacing had no consistent effect on plant N accumulation, and therefore no consistent effect on N uptake efficiency (plant N accumulation /N supply from the soil plus fertilizer). However, a small increase in soil NO₃-N concentration in the hill at topkill at wider seedpiece spacing suggested plant N accumulation was slightly reduced at wider seedpiece spacing, but at a level that could not be detected from a plant-based measure of N accumulation. The reduced dry matter accumulation, but similar plant N accumulation, resulted in lower N use efficiency (plant dry matter accumulation / N supply) at wider seedpiece spacing. Wider seedpiece spacing also resulted in generally lower values of N utilization efficiency (plant dry matter accumulation / plant N accumulation) for the 40-cm compared with the 20- and 30-cm seedpiece spacings. Effects of seedpiece spacing on N use efficiency parameters were generally consistent across cultivars and fertilizer N rates. Wider seedpiece spacing did reduce the efficiency of N use by the potato crop; however, the magnitude of the effect was small under the conditions of this study.     

Optimization of nitrogen rate and seed density for safflower (Carthamus tinctorius L.) production under low-input farming conditions in temperate climate

Field experiments under low-input farming conditions were conducted in South West Germany (lhinger Hof) and North Switzerland (Wil) in 2004 and 2005 aimed at optimizing nitrogen rate and seed density for the production of the newly introduced safflower (Carthamus tinctorius L.). The experiments were laid out in a four-replicated-split plot design with three nitrogen fertilizer rates (0, 40, 80 kg/ha) as main plots and cultivars (Sabina, Saffire, BS-62915) and seed densities (50, 100, 150 seeds/rn2) randomized in split plots. It was shown that many traits responded differentially across environments to rate of nitrogen and seed density. Application of 40 and 80 kg N/ha did not significantly affect most of the investigated traits. At Ihinger Hof, the total nitrogen fertilizer needed to maximize safflower yield was estimated to be 86 kg N/ha. At Wil, residual soil nitrogen alone resulted in satisfactory seed yield when safflower followed a crop fertilized at a commercial rate. The nitrogen rate × seed density interaction was only significant for seed yield and Alternaria leaf spot disease. Nitrogen rates provided significant increases in seed yield at high seed density compared to low seed density. Seed density did not reveal any significant variation in seed yield, oil content, and oil yield. On average, the low seed density produced substantially higher numbers of heads/plant and seeds/plant compared to medium and high densities. These results demonstrate the ability of safflower to use residual soil nitrogen efficiently and to compensate for low plant density.     

不同氮量和密度对吉单96冠层特性及产量的影响

在大田条件下设置纯氮用量0、150、225、300和375 kg/hm~2共5个氮肥量级和6万、7万、8万、9万和10万株/hm~2共5个密度梯度,研究不同氮肥量级条件和不同密度梯度下吉单96的冠层生理及结构指标、产量及产量构成指标。结果表明,冠层叶绿素含量的敏感时期为大喇叭口期和抽雄期,其中,大喇叭口期叶片叶绿素含量受氮肥影响最大,抽雄期叶片叶绿素含量受密度影响最大。225～300 kg/hm~2施氮量且分配60%的追肥可以保持冠层叶绿素在较高水平;叶面积指数受密度调控更显著,7.7万～8.0万株/hm~2为试验最适密度,可维持最大叶面积指数在5.5左右。在中高肥力条件下,采用7.7万～8.0万株/hm~2的种植密度和225～300 kg/hm~2的施氮量,可维持冠层结构和功能,协调穗粒数和百粒重同步增长,产量可达到12 780.9 kg/hm~2。     

不同氮肥运筹对东北春玉米氮素吸收和土壤氮素平衡的影响

在吉林省榆树市粮食高产示范区,以先玉335为试验材料,通过田间试验研究不同氮肥运筹对春玉米的生长、产量及土壤氮素平衡的影响。结果表明,适宜氮肥运筹方式能显著提高玉米产量,施氮量200 kg/hm2,全部用作基肥不追肥(基追比1∶0)处理前期氮素供应过量,导致氮素向子粒转运量减少,过多保留在营养体中,致使产量和氮素利用效率相对其他处理较低;氮肥1/5基施,2/5拔节期追施,2/5大喇叭口期追施(基追比为1∶2∶2)的处理有较高的氮肥农学利用率、氮肥利用率和氮肥偏生产力。玉米生育期田间氮肥的表观损失主要由一次性过量施肥造成,增大拔节后追肥比例增加了收获后土壤的无机氮残留。对氮肥的调控应结合作物养分不同阶段需求及土壤养分供应,达到玉米高产和提高氮肥利用效率,减少氮肥损失对环境带来的危害。     

秸秆还田配施氮肥对春玉米氮素利用及土壤氮素平衡的影响

通过8年田间定位试验,研究玉米秸秆还田配施氮肥对春玉米产量、剖面土壤无机氮积累、氮素平衡和氮肥利用效率的影响。结果表明,通过线性加平台回归方程,求得2012~2019年最高玉米产量所需的适宜施氮量依次为202.7、193.7、182.2、171.2、163.6、156.1、150.7和150.5 kg/hm²。氮素表观损失量和土壤残留矿质氮量均随着施氮量增加而显著增加,两者与施氮量之间均呈显著正相关。每增加10 kg/hm²施氮量,土壤残留矿质氮量、氮素表观损失量分别增加9.09~10.34、5.89~7.34 kg/hm²。当施氮量超过150 kg/hm²时,各处理间玉米吸氮量差异不显著,土壤残留矿质氮、氮素表观损失量之间差异均达显著水平（P<0.05）。随着施氮量增加,氮肥利用率呈先增加后减小趋势,当施氮量为150 kg/hm²时,两年氮肥利用率分别达到最高（75.2%和92.3%）。当施氮量为210~330 kg/hm²,剖面土壤无机氮残留量显著增加,造成土壤无机氮在土壤深层（60~100 cm）的大量累积。     

Different irrigation and nitrogen fertilizer treatments on some agro-physiologic traits in rapeseed (Brassica napus L.)

In order to investigate the effect of irrigation and nitrogen fertilizer on agronomical and physiological traits of two winter rapeseed varieties, an experiment was established in a randomized complete block design as split-plot factorial arrangement with four replications in 2005-2006 at Agricultural Research Station of Khorramabad, Iran. Irrigation as main-plot factor consisted of four levels (I60, I90, I120 and I150). Sub-plot factors included nitrogen in four levels (N0, N70, N140, and N210 kg N ha(-1)) and two varieties (Zarfam and SLM046). Thousand-seed weight (TSW) in all irrigation and nitrogen levels was lower in the 2006 than that of the 2005. Seed oil percentage (SOP) was decreased with increasing water use only in second year. As nitrogen rate increased, SOP decreased and seed oil yield (SOY) increased in the 2006 significantly (p < 0.05). With increasing water supply, SOY increased in first year. Zarfam variety had a higher TSW and SOP in both years. According to combined analysis results, seed and oil yield were not significantly affected by irrigation treatments and rapeseed varieties. Seed yield had not significant difference between 70 to 210 kg N ha(-1) treatments. Both Water Use Efficiency (WUE) and dry matter remobilization efficiency (DMRE) were increased by decreasing water supply in I90 to I150 treatments. But N0 and N210 resulted in the lowest WUE and DMRE, respectively. Considering all traits, the first year of experiment was better than second year. The irrigation x variety interaction had a significant (p < 0.01) effect on seed yield and WUE. Generally, I150N70V1 combination is recommended in the region of the study due to high performance in production of seed and oil yield.     

Impacts of fertilization systems on nitrogen loss and yield of oilseed rape (Brassica napus L.)

Farmyard manure is considered as a source of plant nutrient supply, but high N loss and low N use efficiency are often serious challenges facing this source of nutrient. It is supposed that a combination of manure with inorganic fertilizers can reduce this problem. A two year experiment was conducted in 2004-2005 at Mazandran province of Iran in order to study the effects of manure, inorganic nitrogen and combination of manure-inorganic nitrogen on N loss and yield of winter oilseed rape (Brassica napus L.) under rainfed conditions. Treatments included 0, 50, 100 and 150 kg N ha(-1) urea (F0, F50, F100, F150), 100 kg N ha(-1) urea + 50 kg N ha(-1) manure (F100M50), 50 kg N ha(-1) urea + 100 kg N ha(-1) manure (F50M100), 150 kg N ha(-1) manure (M150). The highest grain yield (3 ton ha(-1)) was obtained with the 150 kg N ha(-1) as urea treatment in both years. Grain yield in M150 treatment was significantly lower (p < 0.05) than F150. However F100M50 and F50M100 resulted in similar yields compared with F150 treatment. Results also showed that F100M50 and F50M100 treatments decreased N loss (4 and 3 kg N ha(-1) year(-1), respectively) compared to application of manure alone (33.5 kg N ha(-1) year(-1)) and F150 (36 kg N ha(-1) year(-1)). Overall, it could be conducted that F100M50 is the best treatment because it produced similar grain yield compared to F150 while resulted in lower N loss as well.     

平衡施肥对春玉米产量及养分吸收的影响

在吉林省玉米主产区采用田间试验研究平衡施肥对玉米产量、养分吸收利用和土壤养分表观平衡的影响。结果表明,与农民习惯施肥（FP）相比,平衡施肥（OPT）在减施氮肥17.0%～37.7%、减施磷肥39.2%～48.7%的情况下,玉米产量提高2.3%～3.1%。OPT处理的养分吸收总量和肥料利用效率有不同程度的提高,其中氮吸收量提高12.3～25.4 kg/hm²,磷吸收量提高0.8～2.9 kg/hm²,钾吸收量提高2.8～4.5 kg/hm²,肥料利用效率提高13.7～19.6个百分点。平衡施肥处理的氮、磷、钾养分平衡系数分别为0.92～1.11、0.83～0.96、0.67～0.77,均好于农民习惯施肥,说明平衡施肥的氮、磷、钾等养分投入基本合理。     

玉米自交系氮高效指标的筛选及综合评价

以47个玉米自交系为材料,测定玉米自交系在低氮和正常氮处理下株高、穗位高、叶绿素SPAD值、吐丝期叶面积指数、吐丝期干重、全株干重、产量、子粒氮积累量、全株氮积累量和氮肥生产效率等10个指标,以耐低氮指数为参数,结合其变异系数,运用相关性分析、主成分分析和隶属函数法对其氮高效能力进行综合评价。结果表明,叶绿素、全株干重、产量、子粒氮积累量、全株氮积累量和氮肥生产效率等可作为玉米自交系氮高效能力的筛选指标。通过聚类分析,筛选得到PH6WC、郑58、PH6WC×郑58、PH6WC×D1798Z、D1798Z×521、HCL645×C7-2、HCL645×C7-2×单598、外杂二环系、美杂二环系×郑58、DH351×郑58、XL21×PH6WC共11个低氮高效型玉米自交系。     

控释氮肥对东北春玉米产量及土壤-作物体系内氮素平衡的影响

采用定位试验开展控释氮肥对春玉米产量及氮素在土壤-作物体系内平衡研究。结果表明,100%控释氮肥基施与100%普通速效氮肥基施比较,平均增产5.1%,玉米地上部氮素吸收总量平均增加6.6%,氮肥表观利用率平均提高2.4个百分点,氮肥农学效率平均提高2.0 kg/kg,土壤-作物体系内氮素盈余-10.2 kg/hm~2。60%控释氮肥与40%速效氮肥混合一次性施用与普通速效氮肥40%基施+60%追施比较,平均增产7.3%,玉米地上部氮素吸收总量平均增加8.8%,氮肥表观利用率平均提高6.8个百分点,氮肥农学效率平均提高3.0 kg/kg,土壤-作物体系内氮素盈余-17.7 kg/hm~2。75%控释氮肥基施与75%速效氮肥基施比较,平均增产7.5%,玉米地上部氮素吸收总量平均增加6.7%,氮肥表观利用率平均提高7.0个百分点,氮肥农学效率平均提高3.8 kg/kg,土壤-作物体系内氮素盈余-14.9 kg/hm~2。     

前期控氮对夏玉米产量、物质生产及氮素利用的影响

试验以郑单958为材料,在79500株/hm2密度下研究了前期控氮对玉米产量、物质生产及氮素利用的影响。结果表明,在大喇叭口期施氮120kg/hm2的条件下,前期按30～60kg/hm2进行适度控氮,产量可达到10108.5～10170.0kg/hm2,氮肥利用率为32.78%～33.35%。前期适当控氮保证玉米苗期对氮素的需求,达到蹲苗的效果,控上促下,培育壮苗,提高根系的吸收和合成能力。前期适度控氮还可保持植株后期较强的光合生产能力,增强根系吸氮能力,保证子粒有充足的碳氮来源,并促进干物质及氮素向子粒的运转,实现玉米产量与氮素利用的协同提高。     

缓效和速效氮配施对春玉米产量、养分积累及氮肥利用的影响

为研究稳定性缓释肥与尿素配施的玉米增产增效效应,采用田间试验,设5种处理,CK(不施肥)、NPK(习惯施肥)、80%C(80%缓释肥)、60%C+20%Ub(60%缓释肥+20%尿素基肥)和60%C+20%Ut(60%缓释肥+20%尿素追肥)。结果表明,60%C+20%Ut处理能够增加有效行粒数和百粒重,显著提高春玉米产量,达10 256 kg/hm²。各处理玉米整株养分含量和积累量均表现出氮>钾>磷,玉米养分积累量以玉米子粒和叶的氮积累量最高,分别为153.87、106.76 kg/hm²;玉米茎对K的积累量最多,以60%C+20%U处理最高,为83.75 kg/hm²;60%C+20%Ub和60%C+20%Ut处理均能提高氮肥农学效率、偏生产力、表观利用率和氮收获指数;在经济效益上,60%C+20%Ut处理的纯收入最高。综上,在贵州黄壤区氮肥减量20%下的缓释肥和尿素配施更能促进玉米高产,达到减氮增产增效的目标。     

种植密度和施氮量耦合对夏玉米干物质积累及氮肥利用率的影响

以郑单958和中单909为试验材料,设4.5万、6.75万、9.0万株/km~2 3个种植密度和0、100、300、500 kg/km~2 4种施氮水平,分析种植密度与施氮量对夏玉米干物质积累量和氮肥利用率的影响。结果表明,玉米在种植密度9.0万株/hm~2,其叶面积指数、群体干物质积累量、总氮素积累量以及产量均显著高于4.5万株/hm~2密度处理。增施氮肥可显著增加玉米叶面积指数、单株干物质积累量、群体干物质积累量、总氮积累量和子粒产量。当施氮量为300~500 kg/hm~2时,叶面积指数、群体干物质积累量及产量不再提加,氮肥利用率和氮肥偏生产力大幅降低。结果表明,郑单958和中单909种植适宜模式为施氮量300~500 kg/hm~2、种植密度9.0万株/hm~2。     

Influence of applied nitrogen on potato part I: Yield,quality, and Nitrogen uptake

Fertilizer nitrogen (N) may be managed to increase crop production and profitability while reducing nitrate contamination of groundwater. A two-year field investigation was conducted to evaluate the effects of applied N on tuber yield and quality, dry matter production and N uptake of potato (Solanum tuberosum L. var. Russet Burbank) grown on irrigated sandy soils in Michigan. Nitrogen was applied as ammonium sulfate [(NH₄)₂SO₄] at rates of 0, 56 and 112, kg N ha^?1 in a single application at planting or 112 and 168 kg N ha^?1 in split applications during the growing season. Total tuber yield generally increased with N applications up to 112 kg N ha^?1. Only one of the three experimental sites showed an increase in marketable tuber yield when 112 kg N ha^?1 was split evenly between planting and tuber initiation. Tuber specific gravity was not affected by N rate. Nitrogen rates of 112–168 kg N ha^?1 maximized dry matter production and plant tissue N concentration at onset of maturity and harvest. Tuber N concentration at harvest ranged from 13–17 g kg^?1 at two of the three locations. Values for the third experiment were 10–13 g N kg^?1. Whole crop N uptake at onset of senescence ranged from 45 to 225 kg N ha^?1 across all locations and treatments. An average of 67 percent of this N was found in tubers at harvest. Nitrogen fertilization exceeded N removal in harvested tubers by more than 50 kg N ha^?1 only for the 168 kg N ha^?1 treatment. These results indicate that acceptable tuber yield can be obtained with lower N rates than those currently used by most producers, with the potential for reducing net loss of N from the soil.     

Effect of nitrogen,phosphorus, and potassium fertilizers on yield components and specific gravity of potatoes

Netted Gem potatoes were grown at four levels of N, three of P, and two of K fertilizer in metal lysimeters protected from rain by an automatic shelter. The first two increments of N fertilizer, 200 and 400lb/acre (224 and 448 kg/ha), successively increased yields by increasing the number of tubers produced. The first increment also increased the average tuber weight. With 800 lb N/acre (896 kg N/ha), tuber yield and grade of potatoes were reduced from those of the 400-lb/acre (448-kg/ha) treatment becuase the average weight per tuber was reduced. P fertilizer increased yield by increasing the average tuber weight. The increased yield due to N and P fertilizers was almost entirely in the form of Canada No. 1 potatoes. K fertilizer did not affect number or weight of tubers in this high-K soil.     

Yield, water use efficiency and nitrogen uptake in potato: influence of drought stress

Summary A lysimeter experiment was performed to study the optimal allocation of limited water supply in potatoes. Irrigation regimes equal to 40, 60 and 80% of maximum evapotranspiration (ET) were evenly applied over the crop cycle. Other treatments involved withholding 80 mm of irrigation, based on ET, beginning at each of three designated growth stages (tuber initiation, early and late tuber growth). An irrigated control treatment, restoring the entire ET, was included for comparison. Continuous drought stress reduced photosynthesis as irrigation volumes were reduced. Plant biomass and tuber yield decreased almost proportionally to water consumption, so that WUE was roughly constant. N uptake was highest in the control and in 80% ET treatment. Withholding water during tuberisation severely hindered plant physiological processes and penalized tuber yield. Reductions in photosynthesis, total biomass and yield were the greatest when drought was imposed during tuber initiation. The earliest stress resulted in the lowest WUE and N uptake. A new crop water stress index (SI) was proposed, which combines atmospheric demand for water and canopy temperature.     

密度和氮肥用量对油菜产量及氮肥利用率的影响?

 为机械化种植油菜,研究不同施氮水平下密度对直播油菜生长发育和氮肥利用效率的影响。以甘蓝型油菜品种中双11号为材料,在低密（15万株/hm2）和高密（45万株/hm2）两种密度下,设施氮0、90、180和270kg/hm2处理,分析施氮量与密度对油菜农学性状、产量、氮肥利用效率的影响,并对比分析了密度与油菜需氮量之间的关系。结果表明,增密后油菜的株高、分枝数、单株角果数和每角粒数显著降低,分枝高度和千粒重显著增加。高密油菜群体株型结构整齐均一,更能满足机械化收获需要。高密处理油菜籽粒产量高于低密处理。施氮0～180kg/hm2时,两个密度下的籽粒产量均随施氮量增加而显著提高,但在270kg/hm2时两密度下油菜产量均有所下降。油菜氮肥表观利用率随着施氮量的增加而下降,但是又随种植密度的增加而增加。说明增加密度能促进氮素向油菜籽粒转移,降低每生产100kg籽粒油菜需氮量,提高氮肥表观利用率。在相同的目标产量（低密下的经济产量、湖北省油菜平均单产和全国油菜平均单产）下,油菜增密后可以节约氮肥用量22.9%~30.6%,增密减氮效果明显。