减氮增施腐殖酸液肥对夏玉米产量和氮肥利用率的影响

为了在保证夏玉米获得较高产量基础上尽量减少氮肥施用量,确定腐殖酸液肥与氮肥的合理配施比例,设置不施氮肥(CK)、正常施氮量(纯N,下同)210 kg/hm~2(100%N)、减施20%氮肥即施N 168 kg/hm~2(80%N)、减施20%氮肥即施N 168 kg/hm~2+腐殖酸液肥1.7 L/hm~2(80%N+WF)、减施40%氮肥即施N 126 kg/hm~2(60%N)、减施40%氮肥即施N 126 kg/hm~2+腐殖酸液肥1.7 L/hm~2(60%N+WF)6个处理,研究减氮增施腐殖酸液肥对夏玉米产量和氮肥利用率的影响。结果表明,与100%N处理相比,80%N+WF处理土壤有机质含量、碱解氮含量、pH值、氮肥回收效率、氮肥生理效率均无显著变化,而氮肥农学效率显著提高9.8%,最终使夏玉米穗粒数、百粒质量及产量与100%N处理接近;但进一步减少氮肥施用量增施腐殖酸液肥(60%N+WF)处理会降低土壤碱解氮和有机质含量,差异均不显著,但较80%N+WF处理降幅增大,虽然也能提高氮肥农学效率和氮肥回收效率,但最终较100%N处理显著降低夏玉米穗粒数(2.7%)和产量(5.2%)。综上,80%N+WF处理在减施氮42 kg/hm~2的情况下能达到100%N处理的效果,土壤肥力较高,氮肥农学效率和氮肥回收效率提高,且穗粒数和产量较高。     

陕西关中不同年代小麦品种产量及氮素吸收利用对土壤肥力的响应

【目的】探讨陕西关中地区小麦品种演替过程中产量及氮效率对土壤肥力的响应。【方法】以20世纪80年代至今关中冬麦区3个代表性小麦主栽品种为材料,以33年长期不同施肥处理构建的土壤肥力水平梯度为平台,研究品种演替和土壤肥力及其交互对作物产量、氮利用效率的影响。供试品种有20世纪80年代品种小偃6号、90年代末品种小偃22和近年品种西农979。长期施肥包括6个处理：不同水平的氮磷化肥配施（N1P1和N2P2）、有机肥与无机肥配施（M1N1P1、M1N2P2、M2N1P1和M2N2P2）,以不施肥为对照（CK）。【结果】在各个肥力水平土壤上,籽粒产量及收获指数均随小麦品种更替而呈现增加的趋势,尤其在高肥力土壤上更为明显。土壤肥力水平的提高显著提高了小麦籽粒产量,其中西农979增产幅度最大（151.0%-610.5%）,其次为小偃22（127.9%-349.7%）,小偃6号增幅最低（148.1%-341.8%）。土壤肥力与品种对小麦籽粒产量及收获指数有显著的交互作用,低肥力条件下,小偃6号籽粒产量高于西农979,高肥力条件下则相反。小麦百公斤籽粒需氮量随品种演替有降低的趋势,但随土壤肥力水平提高有增加的趋势。土壤肥力与品种对百公斤籽粒需氮量也有显著的交互作用。在小麦品种更替过程中氮肥生理效率和农学效率均呈增加的趋势,但随着土壤肥力水平的提高,各品种小麦的氮肥生理效率呈下降的趋势,氮肥农学效率呈先升高后下降的抛物线变化趋势。土壤肥力与品种对小麦氮肥生理效率和农学效率无明显交互作用。【结论】陕西关中小麦品种演替在高肥力以及养分投入充足时不仅表现出单产不断提高,而且氮效率也呈逐步增加的趋势。因此,品种更新的同时还要注重提升土壤肥力,才能保证粮食安全,实现农业生产可持续发展。     

Spatiotemporal Changes in Soil Nutrients:A Case Study in Taihu Region of China

The accurate assessment of the spatiotemporal changes in soil nutrients influenced by agricultural production provides the basis for development of management strategies to maintain soil fertility and balance soil nutrients. In this paper, we combined spatial measurements from 2 157 soil samples and geostatistical analysis to assess the spatiotemporal changes in soil organic carbon （SOC）, total nitrogen （TN）, available phosphorus （AP） and available potassium content （AK） from the first soil survey （in the 1980s） to the second soil survey （in the 2000s） in the Taihu region of Jiangsu Province in China. The results showed that average soil nutrients in three soil types all exhibited the increased levels in the 2000s （except for AK in the yellow brown soil）. The standard deviation of soil nutrient contents increased （except for TN in the paddy soil）. Agricultural production in the 20 years led to increases in SOC, TN, AP and AK by 74, 82, 89 and 65%, respectively, of the Taihu areas analyzed. From the 1980s to 2000s all the nugget/sill ratios of soil nutrients indices were between 25 and 75% （except for AK in the yellow brown soil in the 2000s）, indicating moderate spatial dependence. The ratio of AP in the yellow brown soil in the 2000s was 88.74%, showing weak spatial dependence. The spatial correlation range values for SOC, TN, AP and AK in the 2000s all decreased. The main areas showing declines in SOC, TN and AP were in the northwest. For AK, the main region with declining levels was in the east and middle of western areas. Apparently, the increase in soil nutrients in the Taihu region can be mainly attributed to the large increase in fertilizer inputs, change in crop systems and enhanced residues management since the 1980s. Future emphasis should be placed on avoiding excess fertilizer inputs and balancing the effects of the fertilizers in soils.     

氮肥施用期对春小麦氮素利用和蛋白质产量的效应

春小麦生育期间植株各器官土壤氮与肥料氮变化趋势基本一致。各器官吸收总氮量中,土壤氮约为肥料氮的2～3倍,肥料氮对土壤有激发效应。肥料利用率随氮肥施用期的后移和施用量的增加而逐渐提高。氮肥不同施用期对提高籽粒蛋白质含量有极显著效应(F=31.3>F_(0.01)=4.22),籽粒蛋白质含量随氮肥施用期推迟而显著增加;对籽粒蛋白质产量的效应则差异不显著。生育前期施氮有利于籽粒产量形成,开花期叶面喷施氮肥显著提高籽粒蛋白质含量。     

深耕加秸秆还田下施氮量对土壤碳氮比、玉米产量及氮效率的影响

为明确深耕加秸秆还田条件下的适宜施氮量,研究了深耕加秸秆还田条件下不同施氮量[0、240、270、300(当地生产平均施氮水平)、330、360 kg/hm2N]对土壤碳氮比、玉米产量及氮效率的影响。结果表明,深耕加秸秆还田下增施氮肥可以提高玉米植株干物质和氮素积累量,增加土壤有机质和全氮含量,调节土壤碳氮比,进而提高玉米籽粒产量和氮效率。深耕加秸秆还田条件下,随着施氮量的增加,土壤有机质和全氮含量增加,碳氮比降低;玉米植株干物质积累量、氮素积累量、籽粒产量及氮素农学效率、氮素表观利用率均先增加后降低,以330 kg/hm2处理最高,其籽粒产量、氮素农学效率、氮素表观利用率比当地生产平均施氮水平300 kg/hm2处理分别显著提高9.3%、23.6%、46.7%,但其产量与360 kg/hm2处理差异不显著。表明,深耕加秸秆还田条件下,玉米需适当增加氮肥施用量,试验区玉米适宜氮肥用量以330 kg/hm2(较当地平均施氮水平高10%)为宜。     

施氮量对双季稻氮素吸收和产量的影响及其优化

以双季稻鄱优364和K优117为材料,设置6个施氮水平,研究不同施氮量对双季稻产量、经济效益及氮素吸收利用的影响。结果表明: 在一定的施氮量范围内,水稻产量先随氮肥施用量的增加而增加,而后有所下降,早稻鄱优364最高产量时的施氮量为184 kg·hm-2,晚稻K优117最高产量时的氮肥施用量为228 kg·hm-2。根据当年水稻价格、投肥成本,拟合出水稻纯增收入与施氮量的一元二次曲线,即早稻为 y=-0219　7x2+75787x+2　9547;晚稻为 y=-0167x2+7107x+5 2028。由此得出双季早稻经济效益最高时的施氮量为173 kg·hm-2, 双季晚稻经济效益最高时的施氮量为213 kg·hm-2。增施氮肥可提高稻谷的吸氮量,但双季稻的氮肥农学利用率均随施氮量的增加而降低,早、晚稻氮肥回收效率随施氮量的增加均呈抛物线状。根据双季稻高产、高效并适当提高氮肥利用率的原则,确定了双季水稻最佳施氮量范围。     

播期和施氮量组合对水稻南粳9108产量和氮素利用的影响

为探明播期和施氮量组合对优质水稻品种南粳9108产量构成因素和氮素利用的影响,设3个播期[5月23日(B1)、6月2日(B2)、6月12日(B3)]和4个施氮量[折纯,以N计,0(N0)、180 kg·hm^-2(N1)、270 kg·hm^-2(N2)、360 kg·hm^-2(N3)]进行大田试验。结果表明:水稻的千粒重和产量随着播期推迟逐渐增加,穗数随着施氮量增加而上升。不同播期下,籽粒的氮素分配比率均在N1处理下最大。随着播期推迟,水稻的氮素偏生产力、氮素籽粒生产效率相应增加,氮素农学效率、氮素生理效率先降后升。在同一播期下,水稻的氮素偏生产力、氮素农学效率、氮素吸收效率和氮素籽粒生产效率均随着施氮量增加总体呈下降趋势。总的来看,在本试验条件下,播期推迟、适量氮肥更利于获得高产。综合考虑水稻产量和氮素利用,B2N2或B3N2处理较为适宜。     

Effects of Nitrogen Application Rate and Ratio on Lodging Resistance of Super Rice with Different Genotypes

The objective of this study was to determine the morphology mechanism of nitrogen （N） fertilizer rates and ratio on lodging resistance through analying its effects among lodging index （LI）, lodging-related morphological traits and physical strength in basal intemodes by comparing japonica and indica super rice cultivars. Field experiments, with three nitrogen levels （0, 150 and 300 kg ha-L） and two ratios of basal to topdressing （8：2 and 5：5） with two super rice cultivars （Yliangyou 2 and Wuyunjing 23）, were conducted in the Baolin Farm, Danyang Country, Jiangsu Province, China, in 2011 and 2012. Effects of N fertilizer rates and ratios on morphology of whole plant, morphology traits in basal intemodes and culm＇s physical strength parameters were investigated at 20 d after full heading stage. LI of Yliangyou 2 was significant greater than that of Wuyunjing 23 due to larger bending moment by whole plant （WP） with higher plant height and gravity center height. With higher volume of N fertilizer, LI of two super rice cultivars was increased conspicuously. However, no significant effect was detected with increase of panicle fertilizer ratio. The size of breaking strength （M） in basal intemodes was the key factor determining LI among N fertilizer treatments. Correlation analysis revealed that M value was positively related bending stress （BS） of Wuyunjing 23 and section modulus （Z） of Yliangyou 2, respectively. The higher N fertilizer levels induced reduction ofBS of Wuyunjing 23 due to weak culm and leaf sheath plumpness status and reduced Z of Yliangyou 2 owning to small diameter and culm wall thickness, consequently, influencing their M indirectly. These results suggested that breaking strength was the key factor influencing LI with increase of N fertilizer levels. However, the lodging-related morphology mechanism was different with genotypes. Culm wall thickness and diameter in basal internodes of indica super rice and culm and leaf sheath plumpness status of japonica super rice influenced breaking strength, as well as lodging index, respectively.     

Carbon and Nitrogen Contents in Typical Plants and Soil Profiles in Yanqi Basin of Northwest China

Carbon and nitrogen are the most important elements in the terrestrial ecosystem. Studying carbon and nitrogen distributions in plant and soil is important for our understanding of the ecosystem dynamics and carbon cycle on arid lands. A study was conducted in a typical arid area, the Yanqi Basin, Northwest China. Carbon and nitrogen distributions in plant tissues and soil profiles were determined at 21 sites with typical native plants and crops. Our results indicated that carbon content was similar between crops and native plants, and the average carbon contents in aboveground （42.4%） and belowground （42.8%） tissues were almost the same. Average nitrogen contents in crops were nearly the same （~0.7%） in aboveground and belowground tissues whereas mean nitrogen content was approximately 100% higher in aboveground （2.2%） than in belowground （1.2%） tissues for native species. Soil organic carbon （SOC） and total nitrogen （TN） in cropland （9.4 and 0.9 g kg^-1） were significantly higher than those in native land （6.2 and 0.7 g kg^-1）. Multiple regression analyses indicated that carbon content in belowground tissue and nitrogen content in aboveground tissue were key factors connecting plant and soil in native land. However, there was no significant relationship for carbon or nitrogen between soil and crop, which might reflect human disturbance, such as plowing and applications of various organic materials.     

Nitrogen Nutrition Index and Its Relationship with N Use Efficiency,Tuber Yield,Radiation Use Efficiency,and Leaf Parameters in Potatoes

Knowledge about crop growth processes in relation to N limitation is necessary to optimize N management in farming system. Plant-based diagnostic method, for instance nitrogen nutrition index （NNI） were used to determine the crop nitrogen status. This study determines the relationship of NNI with agronomic nitrogen use efficiency （AEN）, tuber yield, radiation use efficiency （RUE） and leaf parameters including leaf area index （LAI）, areal leaf N content （NJ and leaf N concentration （N0. Potatoes were grown in field at three N levels： no N （N 1）, 150 kg N ha^-1 （N2）, 300 kg N ha^-1 （N3）. N deficiency was quantified by NNI and RUE was generally calculated by estimating of the light absorbance on leaf area. NNI was used to evaluate the N effect on tuber yield, RUE, LAI, NAL, and NL. The results showed that NNI was negatively correlated with AEN, N deficiencies （NNI〈 1） which occurred for N 1 and N2 significantly reduced LAI, NL and tuber yield; whereas the N deficiencies had a relative small effect on NAL and RUE. To remove any effect other than N on these parameters, the actual ratio to maximum values were calculated for each developmental linear relationships were obtained between NNI and tuber RUE to NNI. stage of potatoes. When the NNI ranged from 0.4 to 1, positive yield, LAI, NL, while a nonlinear regression fitted the response of     

施氮量对大棚茬水稻产量、品质及效益的影响

以迟熟中粳品种“通育粳1号”为材料,研究了施氮量对大棚保护地茬水稻产量、品质及效益的影响.结果表明,大田施氮量（纯N）为150 kg/hm^2的产量最高,比不施氮增加26.60%;施氮量在75～150 kg/hm^2范围内,稻谷具有较好的加工品质;施用氮肥能减少稻米垩白粒率,降低直链淀粉含量,提高蛋白质含量;以不施氮为对照,施氮量在150 kg/hm^2时,新增纯收益最大（为13.91%）,而施氮量在75 kg/hm^2时,则可取得最高的边际成本报酬率及氮肥农学利用率.     

Responses of Lowland NERICA and Improved Oryza sativa Rice to Phosphorus and Nitrogen in Sudan Savanna Agroecosystem

The responses of five inter-specific lowland rice cultivars （NERICA-L-19, NERICA-L-20, NERICA-L-41, NERICA-L-42, and NERICA-L-60） and four improved Oryza sativa cultivars （FKR 19, BW 348-1, WITA 4, and SIPI 6923033） to levels of phosphorus and nitrogen fertilization were compared on a Typic Natrustalfat Kadawa in the Nigerian Sudan Savanna in 2006 and 2007 The responses of the NERICA-L eultivars to N and P fertilization were similar to the O. sativa cultivars. In a dry year （2007）, the NERICA-L cultivars gave higher yields than O. sativa cultivars. Phosphorus level did not significantly affect crop physiology, yield, and yield components of all the cultivars. Pooled across cultivars, N and P levels, days to panicle initiation, mid-flowering and maturity were, respectively delayed by 17.0, 15.6 and 6.4 days in 2007 compared to 2006. NERICA-L-42 and NERICA-L-41 were the most stable, exhibiting the least difference in duration to maturity between the two years （3.5 and 4.4 days, respectively）, and could therefore be more adapted to rain-fed environments prone to frequent droughts. Increasing N levels from 0 to 120 kg hal produced yield increments of 62.9 and 37.2% in 2006 and 2007, respectively. Cultivars FKR 19 and WITA 4 gave higher yields in 2006 （3940 and 3542 kg ha^-1, respectively）, while in 2007, NERICA-L-42, NERICA-L^-19 and NERICA-L-20 ranked among the highest in grain yield （3935, 3807 and 3726 kg hal, respectively） and could be recommended to resource-poor farmers. a     

Nitrogen Removal Improvement by Adding Peat in Deep Soil of Su bsu rface Wastewater Infiltration System

In order to enhance the nitrogen removal, a subsurface wastewater infiltration system （SWIS） was improved by adding peat in deep soil as carbon source for denitrification process. The effects of addition of carbon source in the underpart of the SWIS on nitrogen removal at different influents （with the total nitrogen （TN） concentration 40 and 80 mg L^-1, respectively） were investigated by soil column simulating experiments. When the relatively light pollution influent with 40 mg L^-1 TN was used, the average concentrations of NO3-N and TN in effluents were （4.69±0.235）, （6.18±0.079） mg L^-1, respectively, decreased by 32 and 30.8% than the control; the NO3--N concentration of all effluents was below the maximum contaminant level of 10 mg L^-1; as high as 92.67% of the TN removal efficiency was achieved. When relatively heavy pollution influent with 80 mg LITN was used, the average concentrations of NO3--N and TN in effluents were （10.2±0.265）, （12.5±0.148） mg L^-1 respectively, decreased by 20 and 21.2% than the control; the NO3--N concentration of all effluents met the grade Ⅲ of the national quality standard for ground water of China （GB/T 14848-1993） with the values less than 20 mg L^-1; the TN removal efficiency of 94.1% was achieved. In summary, adding peat in the underpart of the SWIS significantly decreased TN and NO3- -N concentration in effluents and the nitrogen removal efficiency improved significantly.     

Effects of Nitrogen on the Competitiveness of Echinochloa colona and Amaranthus viridis with Direct-seeded Rice

Information on weed competitiveness responses to added nitrogen （N） is required to assist with the development of appropriate fertilizer management strategies where weed competition is anticipated. A greenhouse study was conducted to examine the effects of four N rates on the competitive ability ofEchinochloa colona and Amaranthus viridis grown together with direct-seeded rice. Rice and each weed species were grown in a replacement series design at added N rates of 0, 50, 100, and 150 kg ha1. Replacement series diagrams for relative yield showed that competitive ability ofE. colona increased with added soil N. Values of weed aggressivity index for E. colona also significantly increased with the addition of N in the soil. In the absence of added N, A. viridis was more competitive than rice but this relationship slightly changed as N was added. However, values of weed aggressivity index of were statistically similar at all N rates. The results suggest that the competitiveness ofE. colona increased with added soil N, and A. viridis unchanged by soil N levels. Both weed species were different in their response to higher N levels. Information gained in this study could be used to demonstrate the importance of effective weed and fertilizer management.     

Effects of Nitrogen Sources on Nitrate Reductase Activity and Some Physiological Parameters in Psyllium （Plantago ovata F.） under Salinity Stress

The effects of three nitrogen sources （ammonium, nitrate and ammonium＋nitrate） and three salt treatments （0, 100 and 200 mM NaCl） on nitrate reductase activity, proline, soluble protein and carbohydrate contents in psylliom （Plantago ovata） plants were Studied. The nitrate reductase activity tended to increase when NO3- was included in the root-zone solution, but decrease as salinity increased. All N sources stimulated plant growth and nutrient uptake. Shoot and root dry matter tended to decrease as salinity increased, but less so when both NH4＋ and NO3- were present. Shoot biomass accumulated to significantly greater quantities under the mixed-N treatments than when produced using either NH4＋ or NO3- N-form alone. Although not statistically significant, the root biomasses showed a similar tendency. Generally, leaf proline and soluble shoot carbohydrate contents increased with increasing salinity in contrast to soluble protein which decreased regardless of the N source. Under salinity conditions, the concentration of Na＋ in shoot and root tissues was highest in ammonium-N treatment, while that of K＋ was highest in the mixed-N treatment.     

不同栽培模式对华南双季晚稻产量和氮肥利用率的影响

为探讨氮肥运筹和栽插规格等栽培管理措施对华南双季稻产量和氮肥利用率的影响,以杂交稻粤杂889为材料,设置6种栽培模式,分别为不施氮肥(N0),前期重施氮肥的农民习惯栽培(FP,N肥 200 kg·hm^-2,栽插规格20.0 cm×23.3 cm),氮肥后移与不同栽插规格组成的4种栽培模式(简称优化模式),即高产高效1(M1,N肥180 kg·hm^-2,氮肥后移,20.0 cm×20.0 cm)、高产高效2(M2,N肥200 kg·hm^-2,氮肥后移,30.0 cm×13.3 cm,宽行窄株)、高产高效3(M3,N肥180 kg·hm^-2,氮肥后移,25.0 cm×13.3 cm,宽行窄株)和高产高效4(M4,N肥220 kg·hm^-2,氮肥后移,30.0 cm×13.3 cm,宽行窄株),比较不同栽培模式下水稻产量形成特点和氮素吸收利用特征。M1、M2、M3和M4栽培模式,2011年较FP分别增产16.7%、20.5%、18.3%和24.1%,2012年较FP模式分别增产6.3%、16.0%、22.9%和12.8%。与M1相比,M2、M3和M4增产1.3%~15.6%。两年中,M1、M2、M3和M4的氮肥吸收利用率、农学利用率和偏生产力平均比FP提高65.2%~82.4%、55.6%~88.1%和7.9%~33.9%,差异显著。优化模式产量的提高主要与单位面积颖花数和结实率的增加密切相关;4种优化管理模式的平均增产量分别与抽穗至成熟期干物质积累量、成熟期干物质积累量、穗分化始期和成熟期氮素积累量、氮素农学利用率和吸收利用率呈显著或极显著的线性正相关。结果表明,在现有技术的基础上通过优化氮肥用量和栽插规格综合措施具有进一步提高产量和氮肥利用效率的潜力。     

氮素不同底追比例对冬小麦品质和产量的影响

在池栽条件下研究了氮素 3个不同底追比例处理对 2个小麦品种品质和产量的影响。结果表明 ,适当增加追氮比例 ,籽粒品质改善 ,产量提高 ,在本试验土壤肥力条件下 ,氮素以 1/3底施、2 /3追施为兼顾品质与产量的最佳方案     

Revising Nitrogen Recommendations for Wheat in Response to the Need for Support of Variable-Rate Nitrogen Application

Sampling studies in North Dakota conducted from 1994 to 2003 showed that variable-rate N application could be practically directed with zone soil sampling. Results from variable-rate N studies using zone soil sampling were often less than rewarding due in part to the use of a whole-field predicted yield-based formula for developing the N recommendation in each zone. Nitrogen rate studies on spring wheat and durum were established in 2005 through 2009 with the objective to reexamine N recommendations and construct a new system if necessary. The results of the study and archived wheat N response data showed that the state should be divided into three separate N response regions. Within each region historic yields from low to high productivity were defined. The gross N rate was determined using the return-to-N concept developed in the US corn-belt states but with additional consideration for wheat protein value The gross N rate is then modified by credits for previous crop, soil test N from zone soil sampling, tillage systems, excessive straw from the previous year, relative susceptibility to nitrate leaching or denitrification. Finally, the user is encouraged to use common sense and consider whether particular fields have characteristics that require more or less N fertilizer than suggested by the recommendation formulas.     

Phytophthora Root and Crown Rot on Fruit Trees in Bulgaria

Phytophthora root and crown rot was found on the fruit trees in Bulgaria for the first time in the period 1998-1999. Monitoring of the disease spread from 2000 to 2007 points out incidence between 2 and 14 per cent, in some orchards and nurseries in the Southern part of Bulgaria. The following Phytophthora species were identified based on morphological and cultural characteristics, and temperature requirements： Phytophthora cactorum, Phytophthora citrophthora, Phytophthora drechsleri, Phytophthora cryptogea, Phytophthora hybrid specie and Pythium. Prevailing specie was P. cactorum. P. cryptogea and P. cactorum were confirmed by application of molecular methods. Nutritional requirements of P. cactorum and P. citrophthora were studied. Most Nitrogen sources stimulated the mycelial growth of P. cactorum to a higher extend, and reduced the colony size ofP. citrophthora. Different Carbon sources were utilized well by P. cactorum, and only saccharose and maltose had a stimulating effect on the mycelial growth of P. citrophthora. MgSO4.7H20 was the preferred sulfur source for both fungi, as L-cysteine and L-methionine only for P. cactorum. Phytophthora infection leads to physiological changes in the.host plant tissues. The tendency traced out is： about disorders in the amino acid metabolism, increase in the total sugars and slight reduction of the cellulose content. The total nitrogen, phosphorus and potassium content are reduced and the calcium and magnesium are increased. Photosynthesis of inoculated plants was suppressed and transpiration was increased.     

氮肥不同基追比例对水稻产量和氮素吸收利用的影响

以水稻"盛湘1号"为供试材料,在基础地力和施氮量相同的条件下,采用大田试验研究了氮肥不同基追比例对早稻产量和氮肥利用率的影响。结果表明:足够的分蘖肥能够通过促进植株分蘖数增多来提高早稻产量,平衡施用基-蘖-穗-籽肥则可通过增加有效穗数和籽粒数来保证水稻的高产;提高分蘖肥比例和穗肥比例以及平衡施用基-蘖-穗-籽肥均可以提高氮肥农艺利用率、氮肥生理利用率、土壤氮素依存率,但对氮肥偏生产力的影响不显著,与氮肥表观利用率呈现出负相关;氮肥不同基追分施比例处理间各时期植株体内氮素积累量差异显著,分蘖期、孕穗期和抽穗期是水稻吸收氮素养分的高峰期。