减量施氮对玉米-大豆套作体系中作物产量及养分吸收利用的影响

通过田间试验研究了种植方式(玉米单作、大豆单作、玉米-大豆套作)和施氮水平(0、180、240 N kg·hm-2)对玉米和大豆产量、养分吸收及氮肥利用的影响.结果表明:与单作相比,玉米-大豆套作体系中玉米籽粒产量、地上部植株N、P、K吸收量及收获指数略有降低,而大豆籽粒产量、地上部植株N、P、K吸收量及收获指数显著提高.玉米-大豆套作系统的套作优势随施氮量的增加而降低,与当地农民常规施氮量(240 kg·hm-2)相比,减量施氮(180kg·hm-2)处理下玉米和大豆产量、经济系数,以及N、P、K吸收量和收获指数、氮肥农学利用率、氮肥吸收利用率显著提高,土壤氮贡献率降低;与不施氮相比,减量施氮降低了玉米带土壤的全N、全P含量,提高了大豆带土壤的全N、全P、全K含量和玉米带土壤的全K含量.减量施氮水平下,玉米-大豆套作系统的周年籽粒总产量、地上部植株N、P、K总吸收量均高于玉米和大豆单作,土地当量比(LER)达2.28;玉米-大豆套作系统的氮肥吸收利用率比玉米单作高20.2%,比大豆单作低30.5%,土壤氮贡献率比玉米和大豆单作分别低20.0%和8.8%.玉米-大豆套作减量一体化施肥有利于提高系统周年作物产量和氮肥利用率.     

施钾对花生养分吸收、产量与效益的影响

对江淮丘陵地区花生钾素的养分吸收特点以及施钾对花生产量和经济效益的影响进行了研究。结果表明,在一定氮、磷肥供给水平上,增施钾肥,能调节植株体内养分的运输与分配,促进植株对N、P、K养分的吸收,显著提高花生生殖器官的干物质积累,从而有利于提高花生的产量、品质和抗性,每生产100kg荚果,对N、P、K养分吸收量分别为3．08～5．35、0．6～1．2、3．45～6．66kg。其中对K的吸收量最大。主要集中在营养器官中;N、P的吸收主要集中在荚果等生殖器官中,随着施K量的增加,各器官中N、P、K含量均随之增加,但K的增加最多,P增加最少,当施K量为150～180kg·hm^-2,且N、P、K的施肥配比为2：1：2时,花生荚果的产量最高(5425．5kg·hm^-2),经济效益最大(13878．7元·hm^-2),产投比达到6．75：1,增产增收效果显著;而施K量超过225kg·hm^-2时,花生产量和效益明显下降,因此,在花生生产上可以推荐N150P75K150作为该地区高产栽培的平衡施肥配方。     

施氮水平对不同种植制度下玉米氮利用及产量和品质的影响

研究了不同施氮量对套作和单作条件下春、夏玉米氮利用以及产量和品质的影响. 结果表明,随着施氮量的增加,单作和套作条件下,春、夏玉米吸氮量显著增加,籽粒产量、生物产量和籽粒蛋白质产量也显著增加.由于春、夏玉米需求的养分种类与形态一致,低氮条件时竞争较激烈,春玉米处于优势地位,但其吸氮量仍低于单作.增加施氮量可以缓解这种竞争,利于玉米的高产优质.施氮量由187.5 kg·hm^-2增至375 kg·hm^-2时,春、夏玉米单作时生物产量平均增加1.717 kg·kg^-1 N,而套作时平均增加12.179 kg·kg^-1 N;春、夏玉米单作时蛋白质产量平均增加0.305 kg·kg^-1 N,而套作时平均增加1.829 kg·kg^-1 N;春夏玉米套作的土地当量比由1.59增加到1.91.与单作相比,春夏玉米套作可显著提高玉米产量和改善品质,增施氮肥有利于套作条件下玉米高产优质潜力的充分发挥.     

氮、磷、钾施用对灯盏花产量和主要提取物收获量的影响

通过设置N、P、K不同施肥量处理,研究了施肥量差异对灯盏花（Erigeron breviscapus（Vant.）Hand.-Mazz.）的生长指标、产量、3种主要提取物（野黄芩苷、总咖啡酸酯和总黄酮）含量及单位面积收获量的影响。结果表明,增施N、P肥对植株生长指标具有促进作用。随着N、P、K肥施用量的增加,植株产量逐渐升高,且以施N肥的增产幅度最大。一定范围内施用N肥可导致灯盏花3种主要提取物含量降低,而P、K肥的施用则对此没有影响。3种主要提取物单位面积收获量与产量之间呈极显著正相关,N、P、K肥的施用可以提高灯盏花的产量从而增加3种提取物的收获量。N、P、K肥施用量分别为103.5、126.0、112.5 kg/hm²时获得的提取物单位面积收获量最大。     

陕西关中小麦-玉米轮作区协调作物产量和环境效应的农田适宜氮肥用量

为了确定陕西关中小麦-玉米轮作区兼顾作物产量和环境效应的农田适宜氮肥用量,通过玉米-小麦-玉米连续3季田间试验研究了作物产量、氮肥利用效率、氮肥表观损失和土壤氮素平衡等对施氮量的响应。结果表明,随着氮肥用量的增加,不同年份作物产量和3季作物累计产量均表现为先增加后降低的趋势,而累计氮肥农学效率、氮肥表观利用率、氮肥吸收效率和氮肥偏生产力均表现为显著的降低趋势。土壤氮素平衡结果表明,随着施氮量的增加,低量施氮时(小麦施N150 kg/hm2,玉米施N180 kg/hm2),氮肥残留显著增加,表观损失和损失率变化不明显,而高量施氮时(小麦施N150 kg/hm2,玉米施N180 kg/hm2),氮肥残留变化不明显,表观损失和损失率却显著增加。回归和相关分析显示,矿质氮在土壤较深层次(100—200cm土层)大量累积是氮肥表观损失的重要途径之一。小麦施N 150 kg/hm2、玉米施N 180 kg/hm2时,作物即可获得相对较高的产量和氮肥利用率,且能保持作物收获前后土壤无机氮库的基本稳定,同时也可将氮肥表观损失降至较低水平。     

长期施肥对作物产量的贡献

以中国科学院沈阳生态试验站16年定位试验为平台,研究了8种施肥制度的增产效应与稳产性能。结果表明:不同施肥处理对作物产量有明显影响,作物平均产量NPK>NP>NK>N>PK>P>K>CK,不施N肥时(即P、K、PK等处理)作物产量低;肥料对作物产量的年际贡献率在N、NP、NK、NPK处理中总体呈上升趋势,而在P、K、PK处理中则表现出下降的趋势;从化肥N、P、K的增产效果上看,总趋势是N>P>K;作物年际间产量的变异系数随化肥的均衡施用呈下降的趋势;玉米在NPK处理时的稳产性能最好,大豆在PK处理的稳产性最好。     

施氮量对不同肥力水平下夏玉米碳氮代谢及氮素利用率的影响

以郑单958为材料,在高产田和中产田两种地力水平下,利用15N标记法研究了施氮量对夏玉米氮素分配率、利用率和碳氮代谢的影响.结果表明:高产田适量施氮可以提高玉米产量,过量施氮没有表现出进一步增产效果,其氮肥利用率较低(29 04%).中产田随施氮量的增加产量提高,但氮素利用率却降低.各个器官15N积累量依次为籽粒>叶片>茎>根>叶鞘>穗轴.在高产田,当施氮量超过300kg·hm-2时,玉米籽粒和叶片中积累15N有所下降,而茎和根中积累15N的量随施N量的增加而增加;在中产田,随着施N量的增加,籽粒和穗轴积累15N量均相应增加.高产田叶片的硝酸还原酶活性、谷氨酰胺合成酶活性和蔗糖磷酸合成酶活性以及籽粒中蔗糖合成酶活性和酸性转化酶活性均是施氮300kg·hm-2时最大,施氮450 kg·hm-2则抑制了其活性的增强,而中产田的各个酶活性则随着施氮量的增加而增加.     

减量施氮对冬小麦-夏玉米种植体系中氮利用与平衡的影响

研究了冬小麦-夏玉米种植体系中减量施N对作物N利用与平衡的影响,结果表明,与原有高量施N处理(N240和N360)相比,在冬小麦季减半施N未引起产量和吸N量的变化。但在原有低量施N处理(N120)下减半施N显著降低了小麦产量和吸N量;在夏玉米季,在上季减半施N的基础上停止施N后作物产量和吸N量均比原固定施N处理显著下降,N平衡计算结果表明,减量施N条件下0～1m土壤N残留和表观损失的数量均显著低于原有施N量处理,作物N利用率显著提高,但在1～2m层次中累积的硝态氮却不因减量施N而下降,说明这一土层的硝态氮可能难以被作物吸收利用,由此可见,在前茬高施N量下减少氮肥用量有利于提高作物的氮肥利用率、减少N残留与表观损失。     

施氮量对不同茬口冬小麦产量及氮肥利用率的影响

为探明不同茬口及施氮量对冬小麦产量及氮肥利用率的影响,以"豫农211"为材料,采用二因素裂区设计。主因素为玉米单作(SM)、玉米大豆间作(MS)、大豆单作(SS) 3个茬口,副因素为N0(0 kg·hm~(-2))、N180(180 kg·hm~(-2))、N240(240 kg·hm~(-2))、N300(300kg·hm~(-2)) 4个施氮量。结果表明:不同施氮水平下,与玉米单作相比,玉米大豆间作和大豆单作茬口冬小麦产量增幅分别为4.74%～10.01%、5.12%～17.05%,且均显著增加;茬口对小麦穗数及穗粒数均有显著影响,对千粒重影响不显著,与玉米单作相比,大豆单作和玉米大豆间作茬口穗数增幅分别为10%～15%、4%～19%,穗粒数增幅分别为2%～21%、4%～20%;施氮量对小麦穗数及千粒重有显著影响,对穗粒数影响不显著;不同茬口与施氮量的交互作用对穗粒数和千粒重差异均达显著水平;同一施氮处理下,茬口处理间氮肥农学利用效率和偏生产力均表现为大豆单作玉米大豆间作玉米单作,且在N180和N240水平下均达显著水平;结合施氮量与产量拟合曲线,相比玉米单作茬口,大豆单作及玉米大豆间作在保证冬小麦产量的同时降低了氮肥的投入,在生产实践中对不同茬口下小麦施氮量具有指导意义;玉米单作茬口,冬小麦最佳经济产量施氮量和最高产量施氮量分别为243和262 kg·hm~(-2);大豆单作和玉米大豆间作茬口,最佳经济产量施氮量分别为196和210 kg·hm~(-2),最高产量施氮量分别为205和222 kg·hm~(-2)。     

氮磷添加及林分密度对大叶相思林土壤化学性质的影响

大气氮(N)沉降随着人类的活动而日趋严重, 加上中国热带亚热带红壤普遍缺磷(P), 许多森林生态系统由于广泛使用磷肥而产生P富集, 直接影响了森林土壤化学特性。林分密度改变林地的光照、温度、湿度和凋落物持水量, 从而影响土壤特性。为了解外源性N和P添加与林分密度对大叶相思(Acacia auriculiformis)林地土壤化学性质的影响, 为大叶相思人工林的种植密度和土壤养分管理提供科学依据, 该研究于2013到2015年, 以4种不同密度(1 667、2 500、4 444和10 000 trees·hm ^-2)的10年生大叶相思人工林为研究对象, 分别进行添加N、P和N+P处理, 在试验结束时采集0-10 cm土壤, 对其pH、有机质含量、N含量、P含量和钾(K)含量进行了测定分析。结果表明: 施N和N+P均显著降低了土壤的pH和速效K含量, 显著提高了林地土壤的碱解N含量。施N还显著提高了林分土壤的全N含量, 施P显著提高了土壤pH, 降低了林分土壤的全N含量。施P和N+P显著提高了土壤有机质、全P和有效P含量。随着林分密度的增加, 各处理的土壤有机质、全N、碱解N、全P、有效P和速效K含量显著提高。N、P添加处理和密度处理对大叶相思林的土壤pH、有机质和N、P、K含量有显著的交互作用。总体来看, N添加、P添加、林分密度及其交互作用对大叶相思的土壤化学性质有显著影响。     

Evaluation of sewage sludge, septic waste and sludge compost applications to corn and forage: yields and N, P and K content of crops and soils

This paper presents the data from two years of experiments concerned with the application of aerobically-digested sewage sludge, anaerobic lagoon septic sludge, sewage sludge compost or fertilizer to soils for grass forage and feed corn (Zea mays L.) production at two different sites 45 km from Truro, Nova Scotia. Crop yields, plant tissue and Mehlich-1 extractable soil nutrients were evaluated; 15 elements were analyzed in the plant tissue and nine elements in the soil extracts. This paper describes the results of crop yields, plant N, P and K content and Mehlich-1 extractable P and K. The research demonstrated the fertilizer produced higher yields of grass forage than the sludge and the compost but equivalent to the sludge in corn yields. Forage and corn N, P and K contents, however, varied with treatment, crop and year, while the compost-amended soils were highest in extractable nutrients. Both sludges and the compost, therefore, could be effective sources of N, P and K for crop production. Compared to the conventional fertilizer, the nutrient availability from the organic amendments (especially N and P) was considerably lower than the 50% assumed at the start of the experiment; the sludges however, provided higher nutrient availability than the compost.     

Effect of N,P, and K on root yield and nutrient levels in the leaves and roots of rutabagas grown in a greenhouse

Summary Experiments were conducted to determine the influence of N, P, and K and of the NP and NK interactions on root yields and tissue concentrations of N, P, and K of rutabagas grown on a sandy loam soil under greenhouse conditions. Root yields were increased by applications of N and K but not by added P. The yield response to N was dependent on K supply. The highest dry matter content in roots was associated with the lowest rates of N and K and the lowest root yields. The N content of tissue at the early vegetative stage increased with increasing rates of N and decreased with increasing rates of P and K. The N content of root tissue at harvest increased at the highest rates of N but was unaffected by rates of P and K. The P and K content of root tissue increased with increasing rates of P and K, respectively. The levels of nutrients in early vegetative tissue associated with optimum yields were about 2.6, 0.24, and 2.0% for N, P, and K, respectively. The corresponding values in the leaf tissue at harvest were about 1.2, 0.12, and 1.5% N, P, and K, respectively. Contribution No.222.     

氮、磷、钾肥不同用量对花生生理特性及产量品质的影响

在田间条件下研究了氮、磷、钾肥不同用量对花生叶片生理特性及产量品质的影响.结果表明:与不施肥处理相比,花生分别单独施用氮、磷、钾肥可提高叶片叶绿素、可溶性蛋白质含量和光合速率,增加SOD、POD和CAT活性,降低MDA积累量,以施N300～450kg.hm-2、施P5O2150～225kg.hm-2、施K2O300～450kg.hm-2的效果最显著;对叶片光合性能的改善,氮肥的作用主要在前期,磷在中后期,钾肥前后期比较一致.施肥可显著提高花生荚果产量,随施氮量的增加花生产量显著提高,施磷、钾肥以中等施肥量(P5O2150kg.hm-2、K2O300kg.hm-2)花生产量最高,钾肥的增产作用大于氮、磷肥.少量施用磷、钾肥(P2O575kg.hm-2、K2O150kg.hm-2)可显著增加花生籽仁蛋白质和脂肪含量,少量施用氮肥(N150kg.hm-2)可显著增加蛋白质含量,大量施用氮肥(N450kg.hm-2)才可显著增加脂肪含量;磷肥对提高籽仁蛋白质和脂肪含量效果明显,氮肥对增加蛋白质含量作用较大,钾肥主要提高了可溶性糖含量.施用氮、磷、钾肥可增加花生籽仁的赖氨酸、蛋氨酸和油酸、亚油酸含量,提高油酸/亚油酸比值,从而改善花生营养品质,延长花生制品的货价寿命.     

Enhanced plant nutrient use efficiency with PGPR and AMF in an integrated nutrient management system

A 3 year field study was conducted with field corn from 2005 to 2007 to test the hypothesis that microbial inoculants that increase plant growth and yield can enhance nutrient uptake, and thereby remove more nutrients, especially N, P, and K from the field as part of an integrated nutrient management system. The field trial evaluated microbial inoculants, which include a commercially available plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhiza fungi (AMF), and their combination across 2 tillage systems (no-till and conventional till) and 2 fertilization regimes (poultry litter and ammonium nitrate). Data were collected on plant height, yield (dry mass of ears and silage), and nutrient content of corn grain and silage. In addition, nutrient content of soil was determined, and bioavailability of soil nutrient was measured with plant root simulator probes. Results showed that inoculants promoted plant growth and yield. For example, grain yields (kg.ha(-1)) in 2007 for inoculants were 7717 for AMF, 7260 for PGPR+AMF, 7313 for PGPR, 5725 for the control group, and for fertilizer were 7470 for poultry litter and 6537 for NH4NO3. Nitrogen content per gram of grain tissues was significantly enhanced in 2006 by inoculant, fertilizer, and their interactions. Significantly higher amounts of N, P, and K were removed from the plots with inoculants, based on total nutrient content of grain per plot. These results supported the overall hypothesis and indicate that application of inoculants can lead to reduction in the build up of N, P, and K in agricultural soils. Further studies should be conducted to combine microbial inoculants with reduced rates of fertilizer.     

Nitrogen distribution in hybrid and local corn varieties and its possible relationship to a declining soil nitrogen pool under shifting agriculture at Indian Church,Belize

Nitrogen levels at harvest in hybrid corn and weeds were determined over a three year period. Nitrogen losses due to grain removal accounted for 45% of all assimilated-N in the milpa. Percent N and percent P levels in the hybrid and a local black corn were also determined. Uptake of nitrogen and phosphorus in roots and leaves of both varieties were sigmoid until reproductive growth was initiated, at which time the percentage of both nutrients in the leaves declined rapidly. Levels in the seed at maturity in the hybrid variety accounted for 78% N and 52% P; levels were 58% N and 50% P in the local corn. Hybrid corn was not considered suitable for local farmers because a high percentage of total-N was removed at harvest and the hybrid had a high susceptibility to weevil attack.     

施肥对蔬菜产量的影响——以寿光市设施蔬菜为例

以寿光市具有代表性的51个设施大棚为研究对象,通过问卷调查的方法分析了化肥施用对蔬菜产量的影响、有机肥施用与增产的关系、施肥量的影响因素和演变规律等.结果表明: 寿光市设施大棚周年投入肥料养分平均为N 3338 kg·hm^-2、P₂O₅ 1710 kg·hm^-2、K₂O 3446 kg·hm^-2,是当地小麦 玉米轮作种植模式的6~14倍,其中,化肥投入的氮、磷、钾量分别约占总量的35%、49%和42%.化肥投入的氮、磷、钾量对蔬菜产量没有显著影响,有机肥投入对蔬菜表现出明显的增产效果.随大棚棚龄的增加,化肥氮、磷、钾的投入量没有显著的变化,有机肥投入量明显降低.蔬菜种植种类、模式和大棚棚龄的差异是导致大棚养分投入量差异大的原因之一.近十几年来,寿光市设施大棚蔬菜有机肥养分投入量明显增加,化肥氮和磷的投入量呈现下降趋势,化肥钾的投入量增加显著,氮、磷、钾养分投入比例日趋合理.     

雄性不育杂种油菜干物质积累与养分吸收规律研究

对雄性不育杂种油菜杂３７、杂３５与常规油菜品种Ｓ７５－１干物质积累、养分吸收累积进行比较研究表明,供试杂交种较常规品种营养生长、生殖生长的对氮、磷、钾素吸收累积均具有优势。不同品种氮素吸收累量与干物质及磷、钾素吸收累积量间有不同的数量相关关系。杂交种籽粒产量与常规品种籽粒产量差异达到ＬＳＲ０．０１极显著水平。     

Acetylene reduction (nitrogen fixation) associated with corn inoculated with Spirillum.

Sorghum and corn breeding lines were grown in soil in field and greenhouse experiments with and without an inoculum of N2-fixing in Spirillum strains from Brazil. Estimated rates of N2 fixation associated with field-grown corn and sorghum plants were less than 4 g of N2/ha per day. The mean estimated N2-fixation rates determined on segments of roots from corn inoculated with Spirillum and grown in the greenhouse at 24 to 27 degrees C were 15 g of N2/ha per day (16 inbreds), 25 g of N2/ha per day (six hybrids), and 165 g of N2/ha per day for one hybird which was heavily inoculated. The corresponding mean rates determined from measurements of in situ cultures of the same series of corn plants (i.e., 16 inbreds, six hybrids, and one heavily inoculated hybrid) were 0.4, 2.3, and 1.1 g of N2/ha per day, respectively. Lower rates of C2H2 reduction were associated with control corn cultures which had been treated with autoclaved Spirillum than with cultures inoculated with live Spirillum. No C2H2 reduction was detected in plant cultures treated with ammonium nitrate. Numbers of nitrogen-fixing bacteria on excised roots of corn plants increased an average of about 30-fold during an overnight preincubation period, and as a result acetylene reduction assays of root samples after preincubation failed to serve as a valid basis for estimating N2 fixation by corn in pot cultures. Plants grown without added nitrogen either with or without inoculum exhibited severe symptoms of nitrogen deficiency and in most cases produced significantly less dry weight than those supplied with fixed nitrogen. Although substantial rates of C2H2 reduction by excised corn roots were observed after preincubation under limited oxygen, the yield and nitrogen content of inoculated plants and the C2H2-reduction rates by inoculated pot cultures of corn, in situ, provided no evidence of appreciable N2 fixation.     

不同施肥方式对茶树新梢氮磷钾含量及光合生理的影响

通过单施、配施和同施氮、磷、钾肥,研究了不同施肥方式下,茶园春、夏、秋季茶树一芽二叶新梢的氮、磷、钾含量及新梢叶片光合生理的变化,并通过逐步回归分析建立了春、夏、秋季茶树叶片净光合速率(P_n)的回归方程.结果表明: 不同施肥方式对茶树春、夏、秋季新梢的氮、磷、钾含量影响较大.相同施肥方式下,夏、秋季茶树新梢的氮、磷含量低于春季,而钾含量高于春季.氮磷钾肥同施有利于春季茶树叶片P_n的提高,而单施磷肥对其产生抑制作用,单施氮肥可显著提高夏、秋季茶树叶片P_n;相同施肥方式下,夏、秋季茶树叶片P_n要高于春季.气孔导度(g_s)、蒸腾速率(T_r)与夏、秋季茶树P_n呈极显著正相关.逐步回归方程及相关分析表明,季节不同,影响茶树叶片P_n的主要生理因子不同,其共同影响因子是胞间CO₂浓度(C_i)和磷含量,其中C_i对茶树P_n有一定的抑制作用,而磷对其有一定的促进作用.     

氮磷高效优质小麦小偃54在京郊的适宜播量与施肥量研究

对小偃54小麦的品质,抗逆性与各年产量变化等特点已进行过大量试验,并已在河南、陕西等省大面积推广。为了在京郊及华北地区能合理栽培这一优质稳产小麦,针对其分蘖力强与耐低营养的特性,1999扑秋在京郊布设了每公顷45kg、75kg、105kg和135kg4个播量等级与每公顷296kgN,31kgP,35kgK和192kgN,62kgP,70kgK2个肥力水平的大田试验。结果表明,该优质小麦在京郊的适宜播量为105kg／hm^2,施肥量为中等肥力即可达6000kg／hm^2的产量,从而可获得投入少,产出高,节约化肥和保护环境的目的。