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1.
Site-specific application of nitrogen (N) to maize (Zea mays L.) may provide economic and environmental benefits. Variations in soil drainage and texture within fields are often believed to cause localized differences in soil N availability and therefore are a potential basis for site-specific N fertilizer application. The objective of this study was to evaluate the effect of imposed variations in drainage conditions in two soils on early season soil water conditions, soil nitrate levels, and crop response to N fertilizer. Maize was grown for three years following conversion from sod. Two soil drainage regimes and three N rates (22, 100 and 134 kg ha–1) were experimentally imposed on plots on two soil types, a clay loam and a loamy sand. Soil water potential and soil nitrate content were intensively monitored for the 0–150 and 150–300 mm soil layers during the early growing season. Early season soil water potentials showed small effects of drainage variability at the 75 and 225 mm depths. However, the clay loam soil experienced prolonged periods of saturation after significant precipitation, while the loamy sand never experienced such conditions. Soil nitrate levels were strongly affected by cropping history, but were also subjected to losses as a result of precipitation and short-term soil saturation. Maize N response was minimally affected by differences in soil drainage conditions in all 3 years. In years with a wet spring, justification exists for higher N fertilizer rates on finer-textured soils. This study therefore showed only moderate potential for varying N application within fields based on soil type and drainage conditions, but suggests that seasonal differences in N dynamics greatly affect maize N response. 相似文献
2.
Spatial and temporal variability of soil nitrogen (N) supply together with temporal variability of plant N demand make conventional
N management difficult. This study was conducted to determine the impact of residual soil nitrate-N (NO3-N) on ground-based remote sensing management of in-season N fertilizer applications for commercial center-pivot irrigated
corn (Zea mays L.) in northeast Colorado. Wedge-shaped areas were established to facilitate fertigation with the center pivot in two areas
of the field that had significantly different amounts of residual soil NO3-N in the soil profile. One in-season fertigation (48 kg N ha−1) was required in the Bijou loamy sand soil with high residual NO3-N versus three in-season fertigations totaling 102 kg N ha−1 in the Valentine fine sand soil with low residual NO3-N. The farmer applied five fertigations to the field between the wedges for a total in-season N application of 214 kg N ha−1. Nitrogen input was reduced by 78% and 52%, respectively, in these two areas compared to the farmer’s traditional practice
without any reductions in corn yield. The ground-based remote sensing management of in-season applied N increased N use efficiency
and significantly reduced residual soil NO3-N (0–1.5 m depth) in the loamy sand soil area. Applying fertilizer N as needed by the crop and where needed in a field may
reduce N inputs compared to traditional farmer accepted practices and improve in-season N management. 相似文献
3.
Dividing fields into a few relatively homogeneous management zones (MZs) is a practical and cost-effective approach to precision agriculture. There are three basic approaches to MZ delineation using soil and/or landscape properties, yield information, and both sources of information. The objective of this study is to propose an integrated approach to delineating site-specific MZ using relative elevation, organic matter, slope, electrical conductivity, yield spatial trend map, and yield temporal stability map (ROSE-YSTTS) and evaluate it against two other approaches using only soil and landscape information (ROSE) or clustering multiple year yield maps (CMYYM). The study was carried out on two no-till corn-soybean rotation fields in eastern Illinois, USA. Two years of nitrogen (N) rate experiments were conducted in Field B to evaluate the delineated MZs for site-specific N management. It was found that in general the ROSE approach was least effective in accounting for crop yield variability (8.0%–9.8%), while the CMYYM approach was least effective in accounting for soil and landscape (8.9%–38.1%), and soil nutrient and pH variability (9.4%–14.5%). The integrated ROSE-YSTTS approach was reasonably effective in accounting for the three sources of variability (38.6%–48.9%, 16.1%–17.3% and 13.2%–18.7% for soil and landscape, nutrient and pH, and yield variability, respectively), being either the best or second best approach. It was also found that the ROSE-YSTTS approach was effective in defining zones with high, medium and low economically optimum N rates. It is concluded that the integrated ROSE-YSTTS approach combining soil, landscape and yield spatial-temporal variability information can overcome the weaknesses of approaches using only soil, landscape or yield information, and is more robust for MZ delineation. It also has the potential for site-specific N management for improved economic returns. More studies are needed to further evaluate their appropriateness for precision N and crop management. 相似文献
4.
Recent studies have demonstrated the potential importance of using soil texture to modify fertilizer N recommendations. The
objective of this study was to determine (i) if surface clay content can be used as an auxiliary variable for estimating spatial
variability of soil NO3–N, and (ii) if this information is useful for variable rate N fertilization of non-irrigated corn [Zea mays (L.)] in south central Texas, USA across years. A 64 ha corn field with variable soil type and N fertility level was used
for this study during 2004–2007. Plant and surface and sub-surface soil samples were collected at different grid points and
analyzed for yield, soil N parameters and texture. A uniform rate (UR) of 120 kg N ha−1 in 2004 and variable rates (VAR) of 0, 60, 120, and 180 kg N ha−1 in 2005 through 2007 were applied to different sites in the field. Distinct yield variation was observed over this time period.
Yield and soil surface clay content and soil N parameters were strongly spatially structured. Corn grain yield was positively
related to residual NO3–N with depth and either negatively or positively related to clay content depending on precipitation. Residual NO3–N to 0.60 and 0.90 m depths was more related to corn yield than from shallower depths. The relationship of clay content with
soil NO3–N was weak and not temporally stable. Yield response to N rate also varied temporally. Supply of available N with depth,
soil texture and growing season precipitation determined proper N management for this field. 相似文献
5.
6.
以宁麦9号和豫麦34为材料,研究施氮量(0、75、150、225、300kg·hm-2)对土壤速效磷质量分数变化、植株磷素吸收、土壤磷素平衡的影响。结果表明,各处理植株磷素吸收均以拔节至开花期为积累高峰期,且随施氮量增加,磷素吸收呈先增后降的趋势,以N225处理最高。磷肥施用显著提高0~40cm土层速效磷质量分数,随施氮量的增加,土壤速效磷质量分数呈降低趋势。土壤-小麦系统磷素平衡呈明显的阶段性,播种至拔节期磷素出现大量的盈余,拔节至成熟期磷素出现不同程度的表观亏缺。在全生育期,2品种磷素表观盈余量均以N225处理最低,N0处理最高。综合考虑小麦产量和磷素平衡特征,宁麦9号和豫麦34在105kg·hm-2的施磷量基础上可分别再降低P2O5用量7kg·hm-2和10kg·hm-2,配施225kg·hm-2施氮量,能够获得较高的小麦产量并减少磷素损失。 相似文献
7.
Machado S. Bynum E. D. Archer T. L. Lascano R. J. Wilson L. T Bordovsky J. Segarra E. Bronson K. Nesmith D. M. Xu W. 《Precision Agriculture》2000,2(4):359-376
Inadequate information on factors affecting crop yield variability has contributed to the slow adoption of site-specific farming (SSF). This study was conducted to determine the effects of biotic and abiotic factors on the spatial and temporal variability of irrigated corn grain yields and to derive information useful for SSF. The effects of water (80% evapotranspiration (ET) and 50% ET), hybrid (drought-tolerant and -susceptible), elevation, soil index (SI)(texture), soil NO3–N, arthropods, and diseases on corn grain yield were investigated at Halfway, TX on geo-referenced locations. Grain yields were influenced by interrelationships among biotic and abiotic factors. Grain yields were consistently high under high water treatment, at higher elevations, and on soils with high SI (high clay and silt). Soil NO3–N increased grain yields when water was adequate. Management zones for variable rate fertilizer and water application should, therefore, be based on information on elevation, SI, and soil NO3–N. The effects of arthropods, diseases, and crop stress (due to drought and N) on corn grain yield were unpredictable. Spider mite (Oligonychus pratensis) and common smut (Ustilago zeae) damage occurred under hot and dry conditions in 1998. Spider mite infestations were high in areas with high soil NO3–N. Moderate air temperatures and high relative humidity in 1999 favored southwestern corn borer (Diatraea grandiosella) and common rust (Puccinia maydis) incidences. Knowledge of conditions that favor arthropods and diseases outbreak and crop stress can improve the efficiency of scouting and in-season management of SSF. Management of SSF can be improved when effects of biotic and abiotic factors on grain yield are integrated and evaluated as a system. 相似文献
8.
N. Tremblay M. Y. Bouroubi B. Panneton S. Guillaume P. Vigneault C. Bélec 《Precision Agriculture》2010,11(6):621-635
A fuzzy inference system (FIS) was developed to generate recommendations for spatially variable applications of N fertilizer.
Key soil and plant properties were identified based on experiments with rates ranging from 0 to 250 kg N ha−1 conducted over three seasons (2005, 2006 and 2007) on fields with contrasting apparent soil electrical conductivity (ECa), elevation (ELE) and slope (SLP) features. Mid-season growth was assessed from remotely sensed imagery at 1-m2 resolution. Optimization of N rate by the FIS was defined against maximum corn growth in the weeks following in-season N
application. The best mid-season growth was in areas of low ECa, high ELE and low SLP. Under favourable soil conditions, maximum mid-season growth was obtained with low in-season N. Responses
to N fertilizer application were better where soil conditions were naturally unfavourable to growth. The N sufficiency index
(NSI) was used to judge plant N status just prior to in-season N application. Expert knowledge was formalized as a set of
rules involving ECa, ELE, SLP and NSI levels to deliver economically optimal N rates (EONRs). The resulting FIS was tested on an independent
set of data (2008). A simulation revealed that using the FIS would have led to an average N saving of 41 kg N ha−1 compared to the recommended uniform rate of 170 kg N ha−1, without a loss of yield. The FIS therefore appears to be useful for incorporating expert knowledge into spatially variable
N recommendations. 相似文献
9.
渭北旱地冬小麦监控施氮技术的优化 总被引：12，自引：1，他引：12
【目的】氮素是限制旱地小麦增产的主要养分因子,不合理施氮不仅难以增加小麦产量,还会造成土壤剖面硝态氮累积、氮素损失增大和氮素利用效率降低。优化氮肥用量推荐方法、解决旱地小麦不合理施氮问题,对旱地小麦可持续生产有重要意义。【方法】基于平衡土壤氮素携出,以稳定作物产量、培肥土壤和调控硝态氮残留为目标,对现有的土壤硝态氮监控施氮方案（施氮量=作物目标产量需氮量+肥料氮素损失量+收获/播前土壤硝态氮安全阈值（55.0/110.0 kg•hm-2）-环境氮素投入量-秸秆还田带入氮素量-种子带入氮素量-生长季土壤氮素矿化量-收获/播前1 m土壤硝态氮）进一步优化,得出公式：施氮量=作物目标产量需氮量+收获/播前土壤硝态氮安全阈值（55.0/110.0 kg•hm-2）-收获/播前1 m土壤硝态氮。应用这一方法在西北典型旱地冬小麦种植区渭北旱塬两年6县30个地块布置田间试验。【结果】在该区域由于不合理施氮或没有规范的氮肥推荐方法,不同试验地播种前1 m土壤累积硝态氮积累量变化较大,介于34.2-708.4 kg•hm-2,平均为165.2 kg•hm-2,其中有17块在小麦播种前超过110 kg•hm-2。优化后的监控施氮技术确定的小麦氮肥用量介于30.0-247.3 kg•hm-2,平均为128.4 kg•hm-2,较农户习惯氮肥用量（171.6 kg•hm-2）减少25.2%。监控施肥和农户习惯施肥的小麦籽粒产量平均分别为5 658和5 489 kg•hm-2,籽粒氮含量为20.8和20.3 g•kg-1,两者均无显著性差异。监控施肥能够显著提高氮素利用率和氮肥偏生产力,较农户习惯施肥分别提高24.0%（由46.3%提高到57.3%）和130.1%（由34.9 kg•kg-1提高到80.3 kg•kg-1）。收获时,农户习惯施肥0-100 cm土层的硝态氮残留量介于17.4-203.4 kg•hm-2,地块间变幅大,平均为70.6 kg•hm-2;而监控施肥介于15.6-113.9 kg•hm-2,平均为51.4 kg•hm-2,稍低于预期的55 kg•hm-2的目标。在降水较多的夏闲期,优化的监控施氮技术可使0-100 cm土层的硝态氮淋失减少47.9%。【结论】优化后的旱地冬小麦监控施氮技术可以方便地确定和有效调控氮肥用量,稳定小麦籽粒产量,提高氮素利用效率和氮肥偏生产力,降低土壤硝态氮残留和淋溶。 相似文献
10.
Precise management of nitrogen (N) using canopy color in aerial imagery of corn (Zea mays L.) has been proposed as a strategy on which to base the rate of N fertilizer. The objective of this study was to evaluate
the relationship between canopy color and yield response to N at the field scale. Six N response trials were conducted in
2000 and 2001 in fields with alluvial, claypan and deep loess soil types. Aerial images were taken with a 35-mm slide film
from ≥1100 m at the mid- and late-vegetative corn growth stages and processed to extract green and red digital values. Color
values of the control N (0 kg N ha−1) and sufficient N (280 kg N ha−1 applied at planting) treatments were used to calculate the relative ratio of unfertilized to fertilized and relative difference
color values. Other N fertilizer treatments included side-dressed applications in increments of 56 kg N ha−1. The economic optimal N rate was weakly related (R
2 ≤ 0.34) or not related to the color indices at both growth stages. For many sites, delta yield (the increase in yield between
control N and sufficient N treatments) was related to the color indices (R
2 ≤ 0.67) at the late vegetative growth stage; the best relationship was with green relative difference. The results indicate
the potential for color indices from aerial photographs to be used for predicting delta yield from which a site-specific N
rate could be determined. 相似文献
11.
Abundance and Community Composition of Ammonia-Oxidizers in Paddy Soil at Different Nitrogen Fertilizer Rates 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Ammonia oxidation, the first and rate-limiting step of nitrification, is carried out by both ammonia-oxidizing bacteria （AOB） and ammonia-oxidizing archaea （AOA）. However, the relative importance of AOB and AOA to nitrification in terrestrial ecosystems is not well understood. The aim of this study was to investigate the effect of the nitrogen input amount on abundance and community composition of AOB and AOA in red paddy soil. Soil samples of 10-20 cm （root layer soil） and 0-5 cm （surface soil） depths were taken from a red paddy. Rice in the paddy was fertilized with different rates of N as urea of N1 （75 kg N ha＂ yr-1）, N2 （150 kg N ha~ yrl）, N3 （225 kg N ha1 yrl） and CK （without fertilizers） in 2009, 2010 and 2011. Abundance and community composition of ammonia oxidizers was analyzed by real-time PCR and denaturing gradient gel electrophoresis （DGGE） based on amoA （the unit A of ammonia monooxygenase） gene. Archaeal amoA copies in N3 and N2 were significantly （P〈0.05） higher than those in CK and N1 in root layer soil or in surface soil under tillering and heading stages of rice, while the enhancement in bacterial amoA gene copies with increasing of N fertilizer rates only took on in root layer soil. N availability and soil NO3--N content increased but soil NH4＋-N content didn＇t change with increasing of N fertilizer rates. Otherwise, the copy numbers of archaeal amoA gene were higher （P〈0.05） than those of bacterial amoA gene in root lary soil or in surface soil. Redundancy discriminate analysis based on DGGE bands showed that there were no obvious differs in composition of AOA or AOB communities in the field among different N fertilizer rates. Results of this study suggested that the abundance of ammonia-oxidizers had active response to N fertilizer rates and the response of AOA was more obvious than that of AOB. Similarity in the community composition of AOA or AOB among different N fertilizer rates indicate that the community composition of ammonia-oxidizers was relatively stable in the paddy soil at least in short term for three years. 相似文献
12.
F. Guastaferro A. Castrignanò D. De Benedetto D. Sollitto A. Troccoli B. Cafarelli 《Precision Agriculture》2010,11(6):600-620
One approach to the application of site-specific techniques and technologies in precision agriculture is to subdivide a field
into a few contiguous homogenous zones, often referred to as management zones (MZs). Delineating MZs can be based on some
sort of clustering, however there is no widely accepted method. The application of fuzzy set theory to clustering has enabled
researchers to account better for the continuous variation in natural phenomena. Moreover, the methods based on non-parametric
density estimation can detect clusters of unequal size and dispersion. The objectives of this paper were to: (1) compare different
procedures for creating management zones and (2) determine the relation of the MZs delineated with potential yield. One hundred
georeferenced point measurements of soil and crop properties were obtained from a 12 ha field cropped with durum wheat for
two seasons. The trial was carried out at the experimental farm of CRA-CER in Foggia (Italy). All variables were interpolated
on a 1 × 1 m grid using the geostatistical techniques of kriging and cokriging. The techniques compared to identify MZs were:
(1) the ISODATA method, (2) the fuzzy c-means algorithm and (3) a non-parametric density algorithm. The ISODATA method, which was the simplest, subdivided the field
into three distinct classes of suitable size for uniform management, whereas the other two methods created two classes. The
non-parametric density algorithm characterized the edge properties between adjacent clusters more efficiently than the fuzzy
method. The clusters from the non-parametric density algorithm and yield maps for three seasons (2005–2006, 2006–2007 and
2007–2008) were compared and agreement measures were computed. The kappa coefficients for the three seasons were negative
or small positive values which indicate only slight agreement. These results illustrate the importance of temporal variation
in spatial variation of yield in rainfed conditions, which limits the use of the MZ approach. 相似文献
13.
基于土壤重金属风险和经济效益的双孢蘑菇菌渣还田量估算 总被引：3，自引：2，他引：1
为确定既能避免较高的土壤重金属污染风险,又满足农业生产较大经济效益的双孢蘑菇菌渣还田量,设置不施肥对照(CK),常规化肥(CF),双孢蘑菇菌渣分别提供25%、50%、75%、100%和125%的N(M1~M5)共7个施肥处理,研究两年稻麦轮作周期土壤重金属Cu、Pb、Zn、Cd含量及污染指数和作物投入产出比。结果表明,随着菌渣年施用量的增加,Cu、Pb和Zn年净增加值呈上升趋势,而Cd年净增加值表现出先减小后增加的趋势。土壤重金属潜在生态风险系数、综合污染系数和投入产出比均与菌渣年施用量存在明显的二次函数关系(P0.05)。基于土壤重金属生态风险和经济效益考虑,双孢蘑菇菌渣适宜还田量应为11 763~12 850 kg·hm~(-2)。 相似文献
14.
Experiments were conducted in the Red River Valley (RRV) of Minnesota to determine the responses of hard red spring wheat (Triticum aerstivum L.) to fertilizer N after a sugar beet (Beta vulgaris L.) crop that varied spatially in canopy color and N content. A color aerial photograph was acquired of the sugar beet field just prior to root harvest, and six sites were selected that varied in sugar beet canopy color, three each of green and yellow canopy sites. The three green sugar beet canopies returned 369, 265, and 266 kg N ha–1 to the soil while the three yellow sugar beet canopies returned 124, 71, and 73 kg N ha–1 to the soil. Spring wheat response to fall-applied urea-N fertilizer (0, 45, 90, 135, and 180 kg N ha–1) was determined the following year at each of the above antecedent canopy sites. Soil NO3-N in the top 0.6 m of soil varied among the locations with a range of 35 to 407 kg NO3-N ha–1 at the green canopy sites and 12 to 23 kg NO3-N ha–1 at the yellow canopy sites. Application of fertilizer N according to traditional recommendation methods would have resulted in fertilizer applications at all three yellow canopy sites and two of the three green canopy sites. At the antecedent green sugar beet canopy sites, fertilizer N had little or no effect on spring wheat grain yields, grain N concentration, anthesis dry matter, and anthesis N content. In contrast, fertilizer N increased all four parameters at the antecedent yellow sugar beet canopy sites. The data indicate that fertilizer N management can be improved by using remote sensing to delineate management zones according to antecedent sugar beet canopy color. 相似文献
15.
Spring barley was grown for 4 years (2001–2004) in field trials at two sites on morainic soil in central SE Norway, with five N level treatments: 0, 60, 90, 120 and 150 kg N ha-1. Regression analyses showed that a selection of soil properties could explain 95–98% of the spatial yield variation and 47–90% of the yield responses (averaged over years). A strategy with uniform fertilizer application of 120 kg N ha−1 (U
N120) was compared with two variable-rate (VR) strategies, with a maximum N rate of either 150 kg N ha−1 (VRN150) or 180 kg N ha−1 (VRN180). These strategies were tested using either Norwegian prices (low price ratio of N fertilizer to yield value; PN/PY), or Swedish prices (high PN/PY). The VRN180 strategy had the highest potential yield and net revenue (yield value minus N cost) at both sites and under both price regimes. Using this strategy with Norwegian prices would increase the profit of barley cropping as long as at least 40 and 31% of the estimated potential increase in net revenue was realized, respectively. Using Swedish prices, uniform application appeared to be as good as or even better economically than the VR methods, when correcting for extra costs of VR application. The environmental effect of VR compared with uniform application, expressed as N not accounted for, showed contrasting effects when using Norwegian prices, but was clearly favourable using Swedish prices, with up to 20% reduction in the amount of N not accounted for. 相似文献
16.
Yulin Liao Xiangmin Rong Shengxian Zheng Qiang Liu Meirong Fan Jianwei Peng Guixian Xie 《Frontiers of Agriculture in China》2009,3(2):122-129
Radishes (Raphanus sativus L.) were grown in plastic pots in a screenhouse to investigate the influences of nitrogen fertilizer application rates (NFAR)
on yield, nitrate content, nitrate reductase activity (NR), nutrition quality, and nitrogen recovery efficiency (NRE) at commercial
mature stage. Five N-rate treatments, 0.644, 0.819, 0.995, 1.170, and 1.346 g·pot−1, were set up in the screenhouse pot experiments, and nitrogen fertilizer (unlabeled N and 15N-labeled fertilizer) was applied as basal dressing and topdressing, respectively. The results indicated that the fresh and
dry weight yields of radish increased with the increase of NFAR at the range of 0.099 to 0.180 g N·kg−1 soil, decreased at 0.207 g N·kg−1 soil, and accordingly there was a significant quadratic relationship between the fresh and dry weight yields of radish and
the NFAR. At the high addition of urea-N fertilizer, the nitrate content accumulated in the fleshy roots and leaves due to
the decline in NR activity. From 0.644 to 0.819 g N·pot−1 NR increased most rapidly, the highest NR activity occurred at 0.819 g N·pot−1, and the lowest NR activity happened at 1.346 g N·pot−1. Soluble sugar and ascorbic acid initially increased to the highest value and then decreased, and, contrarily, crude fiber
rapidly decreased with the increase of NFAR. Total N uptake (TNU), N derived from fertilizer (Ndff), and N derived from soil (Ndfs) in radish increased, except that Ndfs relatively and slightly decreased at the rate of 0.207 g N·kg−1soil. The ratio of Ndff to TNU increased, but the ratio of Ndfs to TNU as well as NRE of N fertilizer decreased with the increase
of NFAR. Therefore, the appropriate NFAR should be preferably recommended for improving the yields and nutrition qualities
of radish and NRE of N fertilizer.
These authors contributed equally to this work 相似文献
17.
Effects of nitrogen rate and ratio of base fertilizer and topdressing on uptake, translocation of nitrogen and yield in wheat 总被引：1，自引：0，他引：1
Application of nitrogen (N) fertilizer is one of the most important measures to increase grain yield and protein content in
winter wheat (Triticum aestivum L.) production. However, misuse of N Tertilizer will not only affect gram yield and quality, but also cause the decline of
economic benefits and related negative environmental effects. It is essential to study reasonable N application regimes for
profitable yields, efficient N utilization and reduction in possible environmental pollution. The objective of this study
was to determine the N uptake and translocation in wheat plants by using 15N isotope tracers in PVC cylinders (2.05 m long, ϕ 0.2 m, without bottom) in seven treatments: without N fertilizer application
(N0); N application rate of 168 kg/hm2 (0.527 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N1), 1:2 (N2) and 0:1 (N3); N application rate of 240
kg/hm2 (0.753 g/pot), with ratios of base fertilizer to topdressing of 1:1 (N4), 1:2 (N5) and 0:1 (N6). The 15N tracer experiment showed that the main basal N absorbed by plant from sowing to jointing stage accounted for 78.04%–89.67%;
fertilizer N use efficiency (FNUE, N fertilizer accumulation in plant/N supplied) of topdressing was significantly higher
than that of basal N; reducing basal N amount and increasing topdressing N amount could appropriately promote the plant’s
absorption of more N fertilizer and enhance FNUE, of which treatment N2 had the highest values. Under the high-yield condition,
when N fertilizer rate was increased from 168 to 240 kg/hm2, there were no significant differences in the amount of N accumulation in plants and in grains between treatments with the
same ratio of base fertilizer to topdressing; by reducing basal N amount and increasing topdressing N amount accordingly,
the translocation efficiency (TE, accumulation amount from vegetative organs to gram/N accumulation in vegetative organs during
anthesis) increased, and the amount of N assimilation to grains after anthesis and its contribution proportion (the amount
of N assimilation to grains after anthesis/N accumulation in grain) also increased. In other words, grain N accumulation amount
increased with increasing amount of topdressing N at the same N fertilizer rate. There were no significant differences among
treatments N2, N3, N5 and N6 in grain N accumulation. Appropriate N fertilizer rate with a reduction in basal N amount and
an increase in topdressing N amount such as in N2, N5 and N6 increased grain yield and protein content. In conclusion, under
conditions used in this experiment, as far as grain yield, protein content and FNUE are concerned, the recommended appropriate
N fertilizer application regime is treatment N2, with a N fertilizer rate of 168 kg/hm2 and a ratio of base fertilizer to topdressing of 1:2.
Translated from Journal of Acta Agronomica Sinica, 2006, 32(12): 1860–1866 [译自: 作物学报] 相似文献
18.
Variable rate fertilization and precision harvesting could increase the potential for meeting durum wheat quality standards. Field spatial distribution of yield and protein content, and their interactions with soil properties and N fertilization were evaluated in an experiment on durum wheat in North Italy in 2011 and 2012. Variable rate fertilization was adopted in three management zones (MZs) with increasing soil fertility, and a foliar N was applied at flowering to investigate differences in protein quantity and quality. During the crop cycle, changes in crop biomass and N status were monitored through NDVI measurement, and grain was sampled in each MZ and gluten proteins extracted at harvest. Spatial variability of yield and protein content was mainly driven by soil texture and base fertilization in both the years, while foliar fertilization was not efficient in enhancing grain protein content. Variable rate fertilization partially mitigated the weather impact; however, unpredictable weather conditions resulted in low N use efficiency. High N rates were confirmed to provide high protein levels and enhance gluten proteins technological quality, but with a risk for the environment. The marked spatial variability in grain quality in terms of total protein and gluten protein content, and the ratio between glutenin/gliadin and high and low-molecular weight glutenin sub-units, suggested the implementation of zone harvesting as a strategy to exploit the positive interaction between grain quality and soil fertility. 相似文献
19.
Spectral and thermal sensing for nitrogen and water status in rainfed and irrigated wheat environments 总被引：1，自引：1，他引：1
G. J. Fitzgerald D. Rodriguez L. K. Christensen R. Belford V. O. Sadras T. R. Clarke 《Precision Agriculture》2006,7(4):233-248
Variable-rate technologies and site-specific crop nutrient management require real-time spatial information about the potential for response to in-season crop management interventions. Thermal and spectral properties of canopies can provide relevant information for non-destructive measurement of crop water and nitrogen stresses. In previous studies, foliage temperature was successfully estimated from canopy-scale (mixed foliage and soil) temperatures and the multispectral Canopy Chlorophyll Content Index (CCCI) was effective in measuring canopy-scale N status in rainfed wheat (Triticum aestivum L.) systems in Horsham, Victoria, Australia. In the present study, results showed that under irrigated wheat systems in Maricopa, Arizona, USA, the theoretical derivation of foliage temperature unmixing produced relationships similar to those in Horsham. Derivation of the CCCI led to an r
2 relationship with chlorophyll a of 0.53 after Zadoks stage 43. This was later than the relationship (r
2 = 0.68) developed for Horsham after Zadoks stage 33 but early enough to be used for potential mid-season N fertilizer recommendations. Additionally, ground-based hyperspectral data estimated plant N (g kg−1) in Horsham with an r
2 = 0.86 but was confounded by water supply and N interactions. By combining canopy thermal and spectral properties, varying water and N status can potentially be identified eventually permitting targeted N applications to those parts of a field where N can be used most efficiently by the crop. 相似文献
20.
尿素硝铵溶液对黑土区春玉米产量和氮素吸收利用的影响 总被引：6，自引：0，他引：6
【目的】尿素硝铵溶液（urea ammonium nitrate solution,UAN）是集硝态氮、铵态氮和酰胺态氮于一身的液体氮肥品种,兼有3种氮源优势。本研究目的在于明确黑土区春玉米施用UAN的肥效和氮素利用效率,为进一步科学应用及推广提供依据。【方法】2015和2016年在吉林省黑土区设置大田试验,施肥处理包括：不施氮（N0）、尿素一次性基施200 kg N·hm-2（U200）、UAN一次性基施200 kg N·hm-2（UAN200）、尿素基施80 kg N·hm-2+追施120 kg N·hm-2（U80-120）、UAN基施80 kg N·hm-2+追施120 kg N·hm-2（UAN80-120）、尿素基施64 kg N·hm-2+追施96 kg N·hm-2（U64-96）、UAN基施64 kg N·hm-2+追施96 kg N·hm-2（UAN64-96）,追肥时期为拔节-大喇叭口期,施肥深度均为12 cm。测定指标包括籽粒产量、产量性状、植株吸氮量、土壤无机氮含量,并计算土壤-作物系统的氮素平衡、氮素的表观利用、残留和损失状况。【结果】2015和2016年施氮处理的玉米产量、植株吸氮量相比不施氮处理显著提高,均以UAN200处理最高（10.3、11.9 t·hm-2和187.4、288.2 kg·hm-2）,而U64-96处理最低（9.14、10.2 t·hm-2和159.1、243.8 kg·hm-2）。相同施氮量、施用方式条件下,UAN处理的玉米产量均等于或高于尿素处理。2015年UAN在200 kg N·hm-2一次性、分次施用和160 kg N·hm-2分次施用条件下相比尿素分别增加6.1%、2.0%和5.3%,2016年分别增加0.1%、7.8%和7.4%,其中UAN80-120处理显著增产。UAN增产的主要原因是减少果穗秃尖长度而增加单穗粒数。UAN处理的植株氮素吸收量在相同施氮量、施用方式条件下均高于尿素处理,而收获后土壤无机氮残留量和氮素表观盈余量相对较低,因而获得较高的氮素利用率。与UAN200处理相比,UAN64-96处理在减氮40 kg N·hm-2条件下两年玉米产量分别达到9.6和11.0 t·hm-2,其中2015年干旱条件下与UAN200处理无显著差异。而且,UAN64-96处理的土壤氮素表观残留率最低,2015和2016年分别为2.4%和4.4%,而氮素表观利用率最高,分别达到42.6%和52.0%。【结论】相同用量和施用方式下,黑土区玉米施用UAN可获得与尿素相同甚至更高的产量和氮素吸收量,同时土壤氮素残留和盈余较少,氮素利用率明显较高,环境效应较好。从施氮量、产量和氮素利用及损失等方面综合考虑,黑土区春玉米推荐施用160 kg N·hm-2的UAN,以基肥40%和拔节-大喇叭口期追肥60%分次施用。 相似文献