不同施氮量对马铃薯的影响

本试验在固定Ｐ，Ｋ肥下，研究有农家肥［Ｆ１（１５００ｋｇ／亩），Ｆｏ（ｏｋｇ／亩）］下不同施Ｎ量（０，２．５，５．０，７．５ｋｇ／亩）对马铃薯（品种疫不加）生长发育，矿物质营养吸收及产量品质的影响。结果表明：随施Ｎ量增加，叶面积，茎叶生长量，净同化率及块茎膨大速率也增加，Ｎ７．５处理明显优于Ｎ２．５及Ｎｏ处理。施Ｎ增加了Ｎ的吸收，特别是Ｎ７．５处理，对Ｐ，Ｋ的影响不大，同时，也增加了Ｎ，Ｐ，Ｋ的转     

不同施氮量对马铃薯晚疫病发生的影响

氮肥是马铃薯生产中用量较大的肥料之一,其在增加马铃薯产量方面具有不可替代的作用。但由于种植者盲目追求高产,氮肥施用量连年增加,进而导致土壤养分失衡、马铃薯病害发生加剧、马铃薯产量和品质不断下降。为探究施氮量与马铃薯产量及晚疫病发生的关系,田间采用随机区组设计,对抗晚疫病品种‘丽薯10号’、中抗晚疫病品种‘青薯9号’和感晚疫病品种‘中甸红’分别施加 15,20,25,30 和 35 kg/667m²的氮,观察不同施氮量对马铃薯晚疫病及产量的影响。结果表明,不同品种马铃薯在同一施氮水平下,晚疫病发病率、产量不同。‘丽薯 10 号’晚疫病抗性最强、产量最高,其次为‘青薯 9 号’、最差为‘中甸红’。同一马铃薯品种随着氮肥施用量的增加,晚疫病发病率逐渐增加、产量和经济效益逐渐降低。随着施氮量的增加,‘丽薯 10 号’2017 年晚疫病病情指数由 0.47 增加到 0.67,产量从 1 593 kg/667m²减少到1 196 kg/667m²,2018 年晚疫病病情指数由 0.17 增加到 0.22,产量从 1 978 kg/6...     

不同施氮量对水稻病虫害的影响

1　试验方法本试验于 2 0 0 0年在福州市晋安区寿山乡红寮村进行 ,前茬白菜。后茬种汕优 63水稻组合 ,田间试验 ,设不施肥 ,不施氮和 3个施氮量 ,共 5个处理 ,3次重复 ,施肥区 666 7ｍ2 施过磷酸钙 4 0ｋｇ、氯化钾 10ｋｇ。每个处理 ,分病虫防治区和不防治区(观察区 ) ,两区间设 30ｃｍ小田埂 ,四周设保护区。小区面积 133 4ｍ2 ,插秧规格 18 0ｃｍ× 18 6ｃｍ ,每丛插 2粒谷。病虫发生期调查 3次百丛病指和虫量 ,3ｄ观察一次苗情消长 ,抽穗后调查成穗率 ,株高及剑叶 ,倒二叶和倒三叶的长度 ,收割前 1ｄ取样考种。2　结果分析2 1　施氮量…     

不同时期不同施氮量对水稻产量的影响

通过产量构成要素来研究水稻不同时期施用氮肥比例对水稻产量的影响。结果表明:施氮比例为基肥50%、蘖肥30%、穗肥20%的处理产量最高,为506.92 kg/667 m~2,增产率为26.3%,增产效果最明显。     

不同施氮量对大豆吸收化肥氮效率的影响

以(15NH4)2SO4作为标记氮肥,设三个氮肥量,对大豆植株地上部的氮肥吸收率加以研究,结果表明,高氮肥能促进大豆植株对化肥氮的吸收,在低氮处理下,子粒对化肥氮的吸收率更高;大豆各部位间相比,叶片对氮肥吸收率最高,茎、荚果次之,叶片、茎的氮肥吸收率随大豆生长发育而逐渐降低,荚果则呈现高-低-高的变化.     

不同施氮量对单季稻病虫发生的影响

试验结果表明,在水稻分蘖末期-拔节期,随着氮肥施用量增加,稻纵卷叶螟、稻飞虱、纹枯病的发生均显著增加,与不施氮肥的处理比较,每667m2施尿素18 kg、26 kg、35kg、44 kg处理的稻纵卷叶螟蛾幼虫数量分别增加了 225%、338%、496%、561%,卵量分别增加了160%、260%、300%、380%,白背稻虱数量分别增加10.6%、40.7%、70.9%和113.9%.纹枯病不施氮肥的处理未发生,其它处理丛发病率分别为6%、9%、12%和18%.因此,在水稻综合防治与农药减量工作中,应控制氮肥施用量,提高氮肥利用率,减轻病虫危害损失.在病虫防治中,可根据肥力水平与水稻长势进行分类预测和指导,降低农药用量.     

施氮量对不同小麦品种根系的影响

以不同氮利用效率小麦品种为供试材料,通过测定小麦不同时期的根系活力和根条数的方法,研究施氮量对小麦根系的影响。结果表明：根条数和根系活力随着施氮量的增加而增加,且差异显著。矮早8低氮条件下和郑麦366高氮条件下生育中及后期保持了较高的根条数和根系活力,根系衰老较缓,有利于对土壤有效氮的吸收,以郑麦366表现较为明显。     

不同施氮量对棉田氨挥发的影响

为探究施氮量对棉田氨挥发的影响,试验设置0、112.5、168.75和225.0 kg·hm－2 4个施氮量,采用通气法和靛酚蓝比色法测定施肥后棉田氨挥发速率,并计算氨挥发累积损失量和损失率。结果表明：苗期施肥后,各处理的氨挥发累积损失量为2.61～5.77 kg·hm^－2,氨挥发损失率为2.81%～4.63%,占氨挥发总量的61.51%～67.79%。花铃期施肥后,各处理的氨挥发累积损失量为1.24～3.61 kg·hm^－2,氨挥发损失率为2.11%～2.70%,占氨挥发总量的32.21%～38.49%。从棉花的整个生育期来看,氨挥发总量随施氮量的增加而增加,氨挥发总量为3.85～9.38 kg·hm－2,氨挥发损失率为2.46%～3.67%。     

施氮量对马铃薯氮素积累分配及利用率的影响

合理的施肥技术是提高马铃薯产量的主要措施之一。氮肥在马铃薯增产中作用巨大,但是氮肥的不合理施用通常造成马铃薯产量降低、品质下降、氮肥利用率降低。为合理施用氮肥,提高马铃薯产量和氮肥利用率,以鲜食品种‘东农09-33069’为试验材料,研究不同氮肥施用量对马铃薯氮素积累分配规律及其利用率的影响。结果表明,马铃薯植株氮含量、氮素积累量随施氮量的增加而升高。随生育期的推移,马铃薯植株氮素积累量呈先增加后降低的趋势,氮素在茎和叶片中分配比例逐渐降低,块茎中氮素分配比例逐渐升高至成熟期的57%~78%。当施氮量超过10 kg/667m2时,块茎中氮素积累量增加不明显,块茎氮素分配比例不再增加。马铃薯产量在施氮量13.3 kg/667m2时达到最大值,氮素吸收利用率、偏生产力、氮肥农学利用率和氮肥生理利用率在施氮量3.3 kg/667m2时取得最大值。     

施氮量对炸条型马铃薯产量及叶面积的影响

以炸条型马铃薯品种‘抗疫白’(Kennebec)为供试材料,设计6个施氮水平,通过田间小区试验,研究不同施氮量对马铃薯产量和叶面积指数的影响。施氮量与马铃薯产量的关系用二次函数拟合效果良好,方程为y=-0.0012x2+0.3717x+18.6720,对方程求导,当施氮量达到154.8 kg/hm2时产量达到了最大值47.5 t/hm2。不同时期的叶面积指数与产量的关系用二次方程拟合效果良好,对方程求导,获得的叶面积指数适宜的范围,出苗后20,30,40,50,60,70,80和90 d的叶面积指数依次为2.35~2.62,2.84~3.20,4.19~4.66,5.23~5.60,4.31~5.04,4.29~4.96,3.53~4.10和2.78~3.42。     

THE AFTER-EFFECTS OF VARYING RATES OF SPRING APPLICATION OF NITROGEN AND OF DATES OF FIRST DEFOLIATION ON THE YIELD AND BOTANICAL COMPOSITION OF A GRASS/CLOVER SWARD

Mid–season depression of grassland yield following spring application of N was found to be due almost entirely to clover depression, the grass fraction showing no after effects of the treatment. The effect became more marked and lasted longer in successive years. Varying the date of first defoliation in spring did not affect the clover depression significantly. Possible causes contributing to the depressing effect are discussed.     

马铃薯对旱胁迫的反应

为探讨干旱胁迫对马铃薯生理机制的影响,以抗旱性不同的马铃薯品种台湾红皮、会-2和早大白为试材,研究干旱胁迫下马铃薯相关生理指标的变化。结果表明:随着胁迫时间的延长,质膜相对透性、丙二醛(MDA)含量、脯氨酸(Pro)含量增加,而抗坏血酸(AsA)含量降低,超氧化物岐化酶(SOD)和过氧化物酶(POD)活性先升高后降低。抗旱性强的品种质膜相对透性、MDA含量增加的幅度较小,Pro含量增加幅度较大,AsA含量降低的幅度较小,SOD和POD的活性也较高,而抗旱性弱的品种则相反,这些指标及其变化可以作为鉴定马铃薯抗旱能力的依据。     

THE EFFECT OF NITROGEN APPLICATION TO PASTURE ON BEEF PRODUCTION

Five grazing experiments each lasting 2 or 3 years were made between 1955 and 1967, all starting in the first year of ryegrass/cocksfoot/clover or ryegrass/clover leys. A high and a low rate of N, 235 and 45 Ib/ac on average (263 and 51 kg/ha) were compared for beef production. High- and low-N treatments gave mean clover contents for the grazing season of 8 and 24 % on a dry-weight basis, respectively. High N consistently gave a smaller liveweight gain/animal than low N, on average 1±92 and 2±08 Ib/day (0±87 and 0±94 kg/day), respectively. Liveweight gain/ac was 20% greater for high N than for low N, and in terms of net energy the production from high- and low-N, respectively, was 18,500 and 15,000 MJ/ac (45,700 and 37,100 MJ/ha). Data from these experiments, together with published results, were used to calculate a regression of liveweight gain response on N rate and an equation was derived from this to express the output in terms of profit. At 1971 prices profit was maximal at λ0±9/ac (λ2/ha) with 112 Ib N/ac (125 kg N/ha); it was considerably greater at 1973 prices when higher rates of N were justified.     

施氮对高产春大豆氮素吸收分配的影响

以高油品种黑农41为材料研究了高产条件下,氮肥对春大豆植株氮素吸收的影响.结果表明,始花期施氮肥促进氮素吸收,提高氮素的积累速率,推迟氮素积累高峰期,氮素积累总量增加,促进氮素向子粒分配,提高子粒产量和蛋白质含量.在施氮量为0-90kg/hm2范围内,每生产100kg子粒,氮、磷(P2O5)、钾(K2O)吸收量略增,三者之间的比率稳定,约为1:0.28:0.69,再增加氮肥施用量,钾的吸收比率明显下降.     

不同微肥在马铃薯上应用效果的研究

本试验用５ 种微肥喷施马铃薯, 对其产量及产量性状、生长发育、生理指标的影响进行了研究。其结果为, 不同种微肥对其产量及产量性状、生长发育、生理指标具有不同的效果, 其效果显著的有硼、铜、锌三种, 钼和锰效果不显著。     

马铃薯施用磷肥技术研究

本文介绍了马铃薯施用磷肥的技术,其研究结果如下: 1.相关性和校验研究表明,Olsen—P是反映土壤供磷力的理想指标。其供磷力低、中、高、极高的临界点(ppm)分别在2、5、12、40。与小麦的肥力指标并不相同。 2.马铃薯磷肥利用率与土壤速效磷含量呈负相关。其回归方程为(?)=24.7-5.691nx,r=-0.567(n=20)。因土施磷是提高磷肥利用率的决定性措施,经过基础研究,提出了一个估产测土确定磷肥用量的便查表。 3.磷作基肥(种肥)优于追肥。其利用率提高10％,产量提高13～17％,每亩纯收益增长17元。 4.施肥部位以全层集中穴施(或条施)效果最优,全面撒施效果最差,利用率相差7％,每亩纯收益相差26.9元。 5.氨磷配合,腐磷混施分别可提高利用率8％、3％。氮磷配合的相互作用因土壤而异。低肥力土壤有每亩93公斤的正连应效果,中肥力土壤无连应,高肥力土壤出现负连应。腐磷混施有每亩40～45公斤的正连应效果。     

马铃薯氮肥施用技术的研究

本文对马铃薯经济施肥量与土壤、前作、密度、灌溉等栽培条件的关系进行了定量研究。提供了以土测值并综合考虑其他因素的氮肥用量推荐表。还提供了一个根据基础产量或产量目标确定的氮肥用量简表,供无测土条件时应用。旱作时,种肥优于追肥;有灌溉条件时,结合现蕾期浇水深施追肥则优于种肥。深施追肥比表施肥(尿素)提高肥效10％。     

STUDIES OF RESPONSE TO FERTILIZER NITROGEN

The effect of applying 62.8 or 125.6 kg/ha fertilizer N, 4 or 18 days before, 4 days after or immediately after harvesting primary growth at the hay stage on yield of DM, yield of digestible OM (DOM), uptake of N, % CP and % digestibility of OM (OMD) of the primary growth and regrowth from S24 perennial ryegrass were compared with harvesting the primary growth 4 or 18 days earlier. Pre–harvest application of N had no effect on yield of DM or DOM or on % OMD, but significantly increased uptake of N and % CP on a DM basis in the primary growth. The regrowth response was less than from equivalent amounts of N applied after harvest in proportion to the amount of N removed with primary growth. 20–40% N was taken up in the primary growth, even when applied 4 days before harvest. The proportion taken up was not influenced by the interval between application and harvest, but tbere was a marked increase in uptake wben rate of application rose to 125.6 kg N/ha. Harvesting 4 days earlier resulted in slight loss of bulk in the hay which was fully compensated by its extra quality, by improved regrowth and its more effective response to fertilizer N. The low yield of the primary growth harvested 18 days earlier was not compensated by the mass of the regrowth but it produced tbe highest quality primary growdi and top yield of regrowth.     

STUDIES OF RESPONSE TO FERTILIZER NITROGEN

The uptake of N was measured in 2 successive regrowths harvested on 12 June and 13 Aug. following harvests of primary growths 8, 12, 16, 23, 29, 45 and 57 (12 June) days after applying N at 59, 118 or 177 kg N/ha on 16 Apr. Residual responses were obtained to both increments of N, leading to high apparent recoveries of fertilizer N, especially to the higher increment. This increased availability of soil N when high rates of N are applied is shown to vary with date of harvest of primary growth, reaching a maximum equivalent to 151% apparent fertilizer N recovery 23 days after N application. In the second regrowth, percentage N in the herbage showed a negative response to N applied to the primary growth. This appears to reflect a reduction in available soil N brought about by its increased availability and uptake in primary growth and first regrowth. The possibilities of improving the efficiency of fertilizer N by exploiting soil N are considered against the possible reduction in available N for future regrowths.     

STUDIES OF RESPONSE TO FERTILIZER NITROGEN

The effects of 59, 118 or 177 kg N/ha were measured on 7 occasions from 8 to 57 days after application to a perennial ryegrass sward in terms of changes in composition. The first increase Dt of N significantly raised percentages of CP, non-protein N, K, P, Ca, Na and Mg and significantly depressed percentages of DM, OM and OM digestihility. The second increment of N resulted in a further rise in the percentages of CP, true protein, non-protein N, K, P, Ca, Na and Mg; the percentages of DM and OM were further depressed but OM digestihility was not significantly depressed. Percentages of P and Na showed increased responses for the more mature herbage; while percentage non-protein N showed a more marked response in younger herbage. As herbage matured percentages of OM and Na rose, the latter only from days 16 to 45. All other attributes showed falling percentages to levels which could be inadequate for a 500 kg dairy cow yielding 15 kg milk. CP percentage reached this critical level (1.4% N) at days 37, 45 or 56 given 59, 118 or 177 kg N/ha; P percentage became critically low (< 0.36%) at days 27, 35 or 38, respectively; Mg percentage fell to the critical level (0.12%) at days 23, 35 and 46. Na percentage showed the reverse trend, being deficient (< 0.13%) in the earliest samples and becoming satisfactory from days 23 or 27 at 118 and 177 kg N/ha but it remained inadequate at 59 kg N/ba.