Response of wheat and maize to different nitrogen sources: I. Plant growth and biomass accumulation

Maize (Zea mays L., hyhrid Pioneer 3737) and wheat (Triticum aestivum L., cultivar Jantar) were grown hydroponically in nutrient solutions containing 10 mM nitrogen (N) as either the nitrate (NO₃) anion or the ammonium (NH₄) cation or in a 1:1 combination of both. Maize and wheat plants had different responses to the N sources. Maize growth and biomass accumulation were greatest with the equal combination of NO₃ and NH₄, while NO₃ only was more favourable for wheat. The effects of the different N sources were detected on the 14th and 21st day for maize and wheat plants, respectively.     

春玉米土壤矿质氮累积及酶活性对施氮的响应

【目的】东北地区春玉米生产中过量施用氮肥的现象普遍存在,导致氮肥利用效率下降,氮素污染严重。有关施氮对东北春玉米土壤矿质氮累积特性影响的研究鲜有报道。本文利用春玉米土壤矿质氮累积量及氮代谢关键酶活性对施氮的响应行为,探寻春玉米的合理施氮量。【方法】采用田间试验和室内分析相结合的方法研究春玉米土壤矿质氮累积量及氮代谢关键酶活性对施氮的响应行为。设计6个施氮水平(N 0、 60、 120、 180、 240和300 kg/hm2)。自播种开始,每隔15 d分层采集0120 cm土样一次,共取样10次,进行相关指标的测定与计算。收获时,选择代表性的春玉米进行考种测产。【结果】春玉米产量随施氮量增加显著增加,当施氮量高于N 240 kg/hm2时,产量有减少的趋势。土壤中累积的矿质氮以硝态氮为主,其变化行为受施氮量和生育时期的双重制约。土壤硝态氮累积量随施氮量的增加和生育时期的推进均显著增加。受氮肥追施的影响,拔节~大喇叭口期和抽雄期060 cm土层铵态氮累积量与苗期和成熟期相比显著增加;从苗期到抽雄期,060 cm土层的硝态氮累积量显著增加,而60 cm以下土层无规律性变化。除成熟期外,其他3个生育时期土壤硝态氮累积量均随施氮量的增加显著增加,而随着土层的加深呈降低趋势。与施氮量低的处理(无硝态氮累积峰)相比,N240和N300处理的硝态氮累积峰从拔节期的2060 cm迁移到抽雄期的80100 cm,说明过量施氮增加了硝态氮淋溶损失的风险,对环境形成一定的威胁。土壤脲酶和硝酸还原酶活性均随着施氮量的增加先增加后降低,均随着生育时期的推进呈波浪式变化,峰值出现在拔节期~抽雄期,这与土壤中铵态氮和硝态氮累积量的变化趋势相一致。【结论】综合考虑春玉米产量性状、 矿质氮累积量、 氮代谢关键酶活性和经济效益,初步认为,在本试验条件下,春玉米的适宜施氮量在179~209 kg/hm2之间,且在生产上应用该施氮量可以实现氮肥用量降低、 产量增加、 氮肥效率提高及生态环境保护的协调一致。     

Response of wheat cultivars to different soil nitrogen and moisture regimes: III. Leaf water content,conductance, and photosynthesis 1

Two greenhouse studies were conducted with contrasting patterns of soil water availability and nitrogen (N) supply to extend our knowledge of the combined effect of these environmental factors on cultivar response of wheat (Triticum aestivum L.). Several parameters of water relations and photosynthesis were measured. Results showed that at the beginning of stem elongation and before imposing water stress, the low N treatment decreased leaf conductance and carbon dioxide (CO₂) exchange rate (CER). This effect was more significant in the case of the cultivar Nesma than the other cultivars. Leaf conductance was a much better indicator of CER than chlorophyll content. Overall, water stress decreased leaf conductance. Under mild stress, Nesma and Merchouch 8 behaved similarly, but Nesma was more sensitive to water stress. Increased N decreased CER under water stress but tended to have no effect on chlorophyll concentration. Under well watered conditions, N application helped the plants maintain greater leaf conductance, CER, and chlorophyll concentration than low N supply. Cultivar and N effects on relative water content (RWC) were not significant. Under severe water stress, Nesma tended to keep its stomata more open under N stress, while stomata of Merchouch 8 were not sensitive to N level variation. High N decreased leaf RWC of Nesma and Merchouch 8 but had no effect on Saada. From this study we concluded that under non‐water stressed conditions, added N increased leaf water conductance, CER, and chlorophyll. Under water stress, the cultivars responded differently to N application. High N decreased leaf conductance and relative water content. These results indicated that careful cultivar selection can complement good N management of wheat in areas prone to soil moisture stress.     

Response of enzyme activities to nitrogen addition in forest floors of different C-to-N ratios

The effect of different inputs of mineral N on several enzyme activities involved in the C and N cycles was investigated using Oa material of forest floors from four Norway spruce [ Picea abies (L.) Karst.] sites with different C-to-N ratios. The samples from each site were treated with five different concentrations of mineral N (as liquid NH ₄NO ₃). All samples were incubated aerobically for 15–20 weeks at 15°C and at field capacity. Respiration was measured weekly. At the end of the incubation period, four enzyme activities (endoglucanase, ß-glucosidase, polyphenol oxidase and ß-glucosaminidase) and microbial biomass were determined. Endoglucanase activity was increased and ß-glucosidase activity was decreased by N additions only in Oa material having a wide C-to-N ratio. In N-supplemented samples of low C-to-N ratio, increased polyphenol oxidase activities were often detected as a consequence of N addition. ß-Glucosaminidase activity responded positively to mineral N additions, particularly in Oa samples with low internal N concentration. The results of the present study indicate that the effects of N additions on enzymatic activities of organic matter in late stages of decomposition are related to the C-to-N ratio. Increasing inputs of mineral N to spruce ecosystems may especially affect C-hydrolyzing enzyme activities in soils with wide C-to-N ratio leading to an incomplete degradation of cellulose and thus reduced C availability to micro-organisms.     

Changes in nitrate reductase activity,plastid pigment content,and plant mineral composition of wheat,rye, and triticale grown in the presence of aluminum

The effects of aluminum (Al) on nitrate reductase activity, plastid pigment content, and mineral element composition in wheat, rye, and triticale seedlings were studied. Different responses of the plant species to Al content in the growth solution were observed. Under conditions of different Al concentrations (from 1 to 10 ppm), nitrate reductase (NR) activity increased in wheat and triticale, while in rye an interference with nitrate reductase by Al was observed. A definite tendency in plastid pigment content changes independent on Al levels was not found. The chlorophyll “a”;, chlorophyll “b”;, and carotenoid contents were influenced in a different way in wheat, rye, and triticale seedlings. A positive effect of 1, 5, and 10 ppm Al on the nitrogen (N) content in the shoots of wheat and rye was observed. The N content in the shoots of triticale was not affected by the presence of Al. The presence of Al in the nutrient solution led to a tendency toward reduction of potassium (K), calcium (Ca), and magnesium (Mg) contents in the shoots of rye seedlings, a reduction of K in the shoots and manganese (Mn) content in roots of wheat, and a reduction of K in both shoots and roots and an accumulation of Mn in triticale roots. In general, our investigation on the effect of Al in the early stages of wheat, rye, and triticale development showed that a large number of biochemical and physiological parameters are required to characterize the plant responses to Al stress.     

氮及相关的酶活性对小麦根际施肥的反应

In the present experiment,wheat seedlings(Trticucum aestivum L.)were grown on a purple soil with various fertilizer treatments in order to investigate the responses of nitrogen and related enzyme activities in the rhizosphere,The results revealed the increments of both organic matter and total N in the soil with the proximity to the growing roots,especially in treatment of supplying pig manure in combination with chemical fertilizer,suggesting that they could ome from root and microorganism exudation which could be intensified by inorganic-organic fertiliztion,being of benefit to improving the physical and bilogical envi-ronment in the rhizosphere of wheat.Much more inorganic N was observed in the fertilized soils surrounding wheat roots than in the CK treatment ,indicating ,the improvement of crop N supply in the rhizosphere of wheat by fertilization. The activities of invertase,urease and protease in the root zone were greatly enhanced as compared to those in the other parts of soil except that the urease activities were similar in the rhizospher and nonrhi-zosphere of the CK and pig manure treatments,indicating that invertase and protese could be produced by growing roots and rhizosphere microorganisms,in contrast to urease which could be stimulated by urea,Also,significant increment of chemical fertilizer combined with pig manure,suggested that fertilization not only accelerated the renewal of organic matter bu also enhanced bioavailability of organic N in that soil zone .This could be the reason why the total amount of inorganic N available for plants was increased more obviously in the rhizosphere of wheat of the fertilizaton treatments than in taht of the CK treatment.     

不同氮肥管理措施在华北平原冬小麦上的应用效果

在河北省衡水和辛集试验点,采用田间试验研究了氮肥不同用量和不同基追比对冬小麦生长、产量和土壤氮素变化的影响。结果表明,衡水试验点的土壤本底供氮量能满足小麦返青前的正常生长,施氮肥对小麦增产无效,但与施基肥处理相比,不施基肥、仅在拔节和孕穗期2:1分次追肥显著提高了氮肥利用率。在辛集,不施基肥显著影响小麦返青前的生长,施N 60 kg /hm2能满足小麦拔节前的正常生长,不施基肥、仅在拔节后追肥不能消除前期氮缺乏对小麦生长和高产的影响;N 240 kg /hm2以基追比1:3施用时能获得较高的产量和氮肥利用率。冬小麦生育期田间氮肥表观损失主要来源于基肥,但中后期追肥比例过大也增加了收获后土壤的无机氮残留。由于土壤肥力和质地不同,相同氮肥管理方法下两试验点小麦的生长、产量和氮肥利用率的差异较大,因此,为达到作物高产和氮肥高效,对氮肥的同步调控应结合作物养分阶段需求、土壤养分供应特征和土壤肥力、质地的区域分异特征分区进行。     

小麦/玉米苗期磷累积量对介质供磷水平反应的差异

小麦和玉米苗期是磷素营养的关键期和敏感期,研究两种作物苗期对介质供磷反应,可为合理施用磷肥提供参考.试验设缺磷对照、低磷胁迫、中等磷胁迫和正常供磷(P2O5含量分别为0、0.05 mmol·L-1、0.3 mmol·L-1和0.5 mmol·L-1) 4种磷水平,选取小麦"小偃22号"、"兰考4号"和玉米"屯玉65号"、"户单4号"为指标作物,用营养液培养法研究小麦、玉米苗期磷累积量对介质不同供磷水平的反应差异.结果表明,不同介质供磷水平下,两种作物苗期磷累积量显著不同且因作物类型、基因型、器官及测定时期不同而异.总体而言,介质供磷后,苗期早期生长阶段(出苗后25 d以前),小麦的介质最佳供磷水平较玉米高;苗期后期(出苗后40～50 d),小麦和玉米最佳供磷水平一致.如果以低磷胁迫作为对比进行分析,玉米苗期整株磷累积量对介质供磷的敏感性比小麦强;从不同基因型来看:"兰考4号"对介质供磷的敏感性强于"小偃22号","屯玉65号"和"户单4号"基本一致.缺磷条件下小麦较玉米磷效率高,供磷条件下玉米较小麦高;但不同基因型间规律性较差.     

氮锌配施对冬小麦产量及土壤氮素转化相关酶活性的影响

  【目的】  锌(Zn)能够促进冬小麦对氮(N)素的吸收利用。研究氮锌配施对冬小麦土壤氮素形态转化及相关酶活性的影响,有助于探究氮锌配施促进冬小麦吸收利用氮的可能机制,为通过合理施肥提高冬小麦产量和品质提供理论依据。  【方法】  以‘郑麦379’为试材进行壤质潮土培养试验,设置CK (不施N和Zn)、Zn (施Zn 10 mg/kg)、N (施N 0.2 g/kg)、N+Zn (施N 0.2 g/kg+Zn 10 mg/kg) 共4个处理,分析了冬小麦产量及产量构成要素,测定4个生育期植株各部位N、Zn含量,土壤NO₃–-N和NH₄+-N含量及土壤硝酸还原酶、亚硝酸还原酶、脲酶和蛋白酶活性。  【结果】  与CK相比,Zn、N及N+Zn显著提高了冬小麦每盆穗数、穗粒数和籽粒产量,提高了不同时期小麦根、茎叶、穗和籽粒中N、Zn含量,且N+Zn处理的提高幅度明显高于Zn和N处理。随着冬小麦生育期的延长,各处理下土壤NO₃–-N和NH₄+-N含量有所降低,亚硝酸还原酶和脲酶活性有所提高,蛋白酶活性有所降低。N和N+Zn处理能显著提高土壤NO₃–-N含量,且N+Zn在冬小麦生育后期提高土壤NO₃–-N含量的幅度显著高于N处理。Zn、N及N+Zn处理能显著提高冬小麦生育后期土壤NH₄+-N的含量,且N+Zn处理提高的幅度高于Zn处理。Zn处理显著降低了拔节期后土壤硝酸还原酶活性,N及N+Zn处理降低了小麦生育后期土壤硝酸还原酶活性,且N+Zn降低硝酸还原酶活性的程度高于N处理;Zn、N和N+Zn处理均降低了土壤亚硝酸还原酶活性;Zn和N处理显著降低拔节期土壤脲酶的活性,但Zn、N和N+Zn处理均显著提高了土壤蛋白酶活性。  【结论】  氮锌配施提高冬小麦籽粒产量,促进冬小麦吸收土壤氮素,这是由于氮锌配施提高了土壤脲酶和蛋白酶活性,促进了土壤有机氮向铵态氮及铵态氮向硝态氮的转化,同时降低了冬小麦生育后期土壤硝酸还原酶和亚硝酸还原酶活性,抑制了硝态氮的反硝化作用,从而提高了土壤中可供冬小麦吸收的铵态氮和硝态氮含量。     

小麦–玉米轮作体系长期施肥对塿土微生物量碳、氮及酶活性的影响

以20年塿土小麦玉米轮作体系长期肥料定位试验为平台,探讨不同施肥模式下土壤化学肥力要素、微生物量碳氮及酶活性的响应。试验包括不施肥（CK）、单施氮肥（N）、氮磷（NP）、磷钾（PK）、氮磷钾（NPK）、NPK+秸秆（SNPK）以及不同量有机肥+NPK（M1NPK、M2NPK）等8种施肥模式。结果表明,与CK相比,长期施用NP提高土壤有机碳含量达34.0%、全氮34.0%、全磷58.5%、速效磷608.9%、微生物量碳23.3%、微生物量氮54.0%、蔗糖酶53.9%、脲酶132.6%、碱性磷酸酶29.9%以及脱氢酶40.9%。长期施用NPK与NP效果相似,钾素效果甚微。作物秸秆还田配合氮磷钾化肥与氮磷钾相比没有明显影响土壤有机碳、氮和磷水平,但是显著提高微生物量碳的含量（29.5%）、碱性磷酸酶（23.0%）和脱氢酶（26.9%）的活性。有机肥配合氮磷钾与其它施肥处理相比,显著提升土壤化学肥力要素、微生物量碳氮和酶活性,特别是引起了磷素的大量富集（速效磷含量大于150 mg/kg）。因此,塿土不施有机物情况下,氮磷配合可以提高土壤化学和生物肥力,作物秸秆还田配合氮磷钾化肥的培肥效果优于氮磷钾化肥配合,而合理的有机无机肥配合是塿土提升化学肥力和保证生物健康的最佳施肥模式。     

磷素水平对不同大豆品种叶片及子粒谷氨酰胺合成酶活性的影响

盆栽试验选用东农42（高蛋白品种）、合丰25（中间型品种）、东农46（高油品种）3个基因型大豆品种,在每千克土壤施N和K2O各为0.033g基础上,设P0、P5、P10、P15 4个P处理（即每kg土壤分别施P2O5 0、0.033、0.067、0.100g）,研究了不同磷素水平对大豆生育期功能叶片及子粒谷氨酰胺合成酶（GS）活性的影响。结果表明,东农42和合丰25均为P10处理功能叶片和子粒GS活性最高;东农46为P10处理功能叶片GS活性最高,P5处理子粒GS活性最高。同一处理不同品种间东农42功能叶片和子粒GS活性最高,东农46最低,合丰25处于二者之间;3个品种不同处理功能叶片GS活性最高值均出现在结荚期,东农42子粒GS活性处于高值时间较长,东农46最短,合丰25处于二者之间。施磷对3个大豆品种叶片及子粒GS活性有影响,适宜的施磷量有利于提高其活性。     

春玉米产量、氮素利用及矿质氮平衡对施氮的响应

通过在辽宁省昌图县的田间试验,研究了不同施氮水平(0、60、120、180、240和300 kg hm-2)对春玉米产量、氮素利用及农田矿质氮平衡的影响。结果表明:春玉米产量随施氮量增加而显著提高,当施氮量高于N 240 kg hm-2时,产量有减少趋势;氮素当季利用率随施氮量增加先增加后降低,在施氮量180 kg hm-2时达到最大,为27.95%。随着施氮量增加,氮肥农学利用率、氮素吸收效率和氮素偏生产力均显著降低,而氮肥生理利用率和氮肥表观残留率均先增加后降低,这与氮肥表观损失率的变化正好相反。作物吸氮量随施氮量增加而显著增加,氮盈余主要以土壤残留为主,表观损失在氮盈余中的比例虽小,但随着施氮量增加而明显增加。低量施氮(<180 kg hm-2)主要引起土壤矿质氮残留量的显著增加,而高量施氮(240 kg hm-2和300 kg hm-2)主要引起土壤氮素表观损失量的显著增加。在本试验条件下,合理施氮量应控制在180～209 kg hm-2左右。     

Response of wheat cultivars to different soil nitrogen and moisture regimes: I. Dry matter partitioning and root growth 1

The balance between root and shoot growth is one of the mechanisms used by plants to adapt to a particular environment. This balance is affected by nutrient supply and water availability. The objective of this study was to understand how nitrogen (N) affects root and shoot growth of three cultivars of wheat (Triticum aestivum L.) grown under two regimes of soil moisture ('non water stressed’ and ‘stressed’ during stem elongation') in the greenhouse and growth chamber. Data showed that before stem elongation, shoot growth was less sensitive to high soil N levels than root growth. In fact, root growth was inhibited by excessive soil N concentration. The cultivar ‘Nesma’ produced more dry matter, absorbed N more rapidly and avoided the negative effect of high soil N concentrations on root growth. ‘Merchouch 8’ produced less dry matter and tolerated more water stress, and appeared to require less water. Severe water stress masked the effect of N on root and shoot growth, and the negative effect of water stress on growth was more important under high N. Plants which were water stressed during stem elongation could not fully recover when they were rewatered from boot stage to anthesis. Nitrogen application improved shoot but not root growth under this soil moisture situation. This study suggested that shoot and root growth were affected differently by N availability and that high soil N levels enhanced the negative effect of water stress on growth.     

不同穗型小麦品种小花发育成粒对氮肥的响应

为探索不同穗型小麦品种小花发育成粒对氮肥的响应,本试验以大穗型品种‘周麦16’和多穗型品种‘豫麦49’为供试材料,设置不同施氮水平0 kg(N)·hm~(-2)、180 kg(N)·hm~(-2)和360 kg(N)·hm~(-2),观察分析了两个穗型小麦品种小花发育动态模式和结实特性。结果显示,随着生长度日(GDD)的增加,不同氮水平下2品种小花发育动态变化趋势相似,小花分化均符合二次曲线方程模式,退化和败育符合一次线性方程,R2均达显著水平。大穗型品种‘周麦16’小花分化总数显著高于多穗型品种‘豫麦49’,在360 kg(N)·hm~(-2)处理差异极显著;大穗型品种‘周麦16’表现出随施氮量增加,小花分化和退化速率提高,有利于可孕小花的形成、增加结实粒数,最终180 kg(N)·hm~(-2)处理结实粒数显著高于其他处理,较360 kg(N)·hm~(-2)处理平均每穗粒数增加2.04粒;多穗型品种‘豫麦49’尽管分化小花总量不高,但小花退化和可孕小花败育速率较低,在180 kg(N)·hm~(-2)施氮水平表现出高的可孕小花数量和结实粒数,但与高施氮处理相比差异不显著。表明就增加穗粒数而言,两品种均以180 kg(N)·hm~(-2)较为适宜,从最终产量及产量构成分析结果来看,‘豫麦49’表现出与穗粒数相同的结果,而‘周麦16’在高施氮条件下可通过增加成穗数和穗粒数提高产量。     

Response of ATP content, respiration rate and enzyme activities in an arable and a forest soil to nutrient additions

Glucose (C), glucose plus NO₃^- (C+N) or glucose plus NO₃^- plus PO₄^3- (C+N+P) were added to an arable and a forest soil at a single dose, or split into four equal doses over 4 consecutive days, and the response of several enzyme activities, ATP content and respiration rate were monitored for 11 days. ß-Glucosidase activity was reduced in the two soils during the first day by substrate addition. Thereafter, this enzyme activity varied only slightly in the arable soil with reference to the non-amended control, while it increased substantially in the beech forest when C+N and C+N+P were added. Casein-hydrolysing activity increased in the C treatment and decreased after C+N+P addition during the first 4 days in the two soils. After 11 days, protease activity was enhanced in the arable soil when C+N was applied in a split dose. Urease activity decreased during the first 4 h, particularly in the arable soil with the addition of C+N or C+N+P, applied in a single dose, and then continuously increased. Thus, urease responded to high nutrient availability, being firstly repressed or inhibited, and stimulated afterwards. Phosphatase activity was only slightly modified in the arable soil but substantially increased in the beech forest by C+N addition. The presence of P usually decreased phosphatase activity. Arylsulphatase activity was repressed after substrate addition, which was particularly evident in the arable soil. In the beech forest topsoil, C added alone increased this enzyme activity. Significant correlations between ATP content and enzyme activity were only observed for urease in the arable system treated with C+N and in the forest when C was applied in a split dose. The effect of C, C+N and C+N+P addition varied between the arable and the forest soil according to environmental conditions and microbial ecophysiology.     

低磷胁迫对小麦代换系保护酶活性和丙二醛含量的影响及染色体效应

以中国春-Synthetic 6x染色体代换系及其亲本为材料,通过测定孕穗期、开花期、灌浆期不同磷处理条件下叶片的保护酶活性及丙二醛含量,研究低磷胁迫对相关生理性状的影响及染色体效应。结果表明,低磷胁迫下,SOD和POD活性上升,MDA含量增高;Synthetic 6x的2A、3B、2D、7D染色体上可能存在诱导SOD活性增强的基因;2A、5A、6A、7B、7D染色体上可能存在诱导POD活性增强的基因;5A、2D、5D、7D染色体上可能存在抑制MDA含量增高的基因。     

长期不同施肥潮土活性有机氮库组分与酶活性对外源牛粪的响应

【目的】研究不同施肥制度下潮土中活性有机氮库及酶活性对新添加有机物料的响应机制,可深入理解不同施肥制度培肥土壤、提高土壤基础地力的机理。【方法】供试土壤采集于从1986年开始的长期定位试验处理,包括CK (不施肥)、OF (常量有机肥)、CF (常量化肥)、OCF (常量有机无机配施) 4个处理。通过室内恒温培养试验,研究添加等氮量牛粪后长期不同施肥潮土有机氮库组分(微生物量氮、可溶性有机氮和颗粒有机氮)含量及土壤酶(α-葡萄糖苷酶、β-葡萄糖苷酶、β-木糖苷酶、纤维二糖水解酶、磷酸酶、过氧化物酶和酚氧化酶)活性的变化特征。【结果】首先,无论添加牛粪与否,土壤全氮、可溶性有机氮和颗粒有机氮含量均随培养时间呈上升趋势或与初始时期差异不显著;添加牛粪的长期不施肥与施化肥处理土壤微生物量氮含量显著低于相同处理不添加牛粪的土壤微生物量氮含量。其次,培养结束后,添加牛粪增加了长期不同施肥潮土全氮、可溶性有机氮和颗粒有机氮含量,分别提高了5.43%~15.49%、5.83%~69.42%及9.75%~42.29%,却降低了土壤微生物量氮含量16.91%~62.10%。另外,施肥、添加牛粪及其交互作用对土壤酶活性具有显著影响(P <0.05);无论添加牛粪与否,不同施肥处理土壤氧化酶(过氧化物酶和酚氧化酶)活性显著低于不施肥处理,不同施肥处理的土壤水解酶活性却呈现不同的变化趋势。不添加牛粪情况下,长期施肥显著提高了除β-葡萄糖苷酶以外的土壤水解酶活性;其中与长期不施肥处理相比,长期施用化肥土壤β-木糖苷酶和β-纤维素酶分别提高了208.74%和180.75%。添加牛粪情况下长期施用有机肥土壤β-葡萄糖苷酶和β-纤维素酶比不施肥分别提高了201.40%和308.04%;冗余分析(redundancy analysis,RDA)显示,添加与不添加牛粪条件下土壤酶活性的关键环境驱动因子不同,在不添加牛粪时为可溶性有机氮,添加后其关键驱动因子为全氮和可溶性有机氮。【结论】不同施肥制度下土壤微生物量氮、可溶性有机氮、颗粒有机氮与土壤全氮之间呈显著正相关;室内好气培养条件下,添加牛粪显著提高了长期不同施肥潮土的全氮、可溶性有机氮、颗粒有机氮含量,却显著降低了土壤微生物量氮含量;不同施肥制度下土壤酶活性差异显著,牛粪的添加改变了影响长期不同施肥潮土酶活性的关键环境因子。     

不同生态区冬小麦材料产量和品质对追氮量的响应

[目的]通过田间试验,研究拔节期不同量氮肥追施对来源于西藏高原生态区和北部冬麦生态区的冬小麦材料氮素积累、产量及加工品质的影响,为在不同生态区冬小麦的氮肥合理运筹提供理论依据和技术参考.[方法]大田试验采用两因素随机区组设计,A因素为来源于西藏高原生态区的冬小麦材料藏冬25号、肥麦和来源于北部冬麦生态区的冬小麦材料08...     

不同氮肥类型和用量对小麦产量和加工品质的影响

[目的]分析不同用量有机肥氮和化肥氮对小麦籽粒产量和品质的影响,为提升小麦品质提供科学施肥依据.[方法]不同氮肥类型长期定位试验位于山东陵县,始于2006年.肥料分为有机肥氮和化肥氮两大类,用量均设定为0、60、120、180、240、300、360、420、500、600 kg/hm2.2018年取样测定小麦产量和籽...