微喷水肥一体化对冬小麦产量和水分利用效率的影响

为探明不同微喷灌施氮方式对冬小麦产量及水分利用效率的影响,以‘济麦22’为材料,在底施纯氮105kg/hm~2条件下,2016年春季设置追施纯氮45(N1)、90(N2)和135kg/hm~2(N3),每个追氮量采用微喷灌拔节期一次性追施(JS)和分别在拔节、孕穗、开花和灌浆期4次等量追施(4T)2种方式,测定冬小麦的产量和水分利用效率。结果表明:1)微喷灌条件下,随施氮量的增加,冬小麦产量先增加后降低,以N2处理产量最高;相同施氮量下,分次施氮处理产量显著高于拔节期一次性施氮,产量的增加主要由于显著提高千粒重;2)拔节期一次性施氮提高冬小麦开花期群体叶面积指数,而分次施氮处理灌浆期的叶面积指数显著高于拔节期一次性施氮,相同施氮量下分次施氮延缓灌浆中后期旗叶的衰老,从而有利于花后干物质积累和粒重的提高,但过多施氮导致粒重下降,总干物质积累量减少;3)不同施氮量处理间水分利用效率以N2处理最高,相同施氮量下分次施氮处理水分利用效率显著高于拔节期一次性施氮处理。综上所述,与拔节期一次性施氮相比,微喷灌采用分次施氮显著提高冬小麦的产量和水分利用效率,微喷水肥一体化N2处理下分次施氮为最佳的高产高效氮肥运筹模式。     

不同生育期水分亏缺和施氮对冬小麦产量及水分利用效率的影响

【目的】研究不同生育期土壤水分亏缺和施氮对冬小麦产量及水分利用效率的影响,探讨小麦生长的水分亏缺敏感期和合理施氮量。【方法】以冬小麦小偃22为试验材料,设置4个氮肥水平和11个水分亏缺处理,采用盆栽试验,研究不同生育期水分亏缺和施氮水平对冬小麦水分利用效率、产量及其构成要素的影响。【结果】不同生育期土壤水分亏缺和施氮水平对冬小麦产量和水分利用效率有一定影响。与全生育期不亏水处理相比,返青期水分亏缺处理冬小麦干物质显著降低了7.70%,产量、水分利用效率显著增加了4.95%和7.56%;拔节期、抽穗期水分亏缺处理冬小麦干物质显著降低了13.69%,15.88%,产量显著降低了5.69%,8.06%,且对有效穗数、穗粒数也有显著降低作用;灌浆期水分亏缺对冬小麦产量影响不显著,但耗水量显著减少了5.44%,水分利用效率显著增加了8.02%。与全生育期不亏水处理相比,返青期+拔节期、返青期+抽穗期、返青期+灌浆期、拔节期+抽穗期、拔节期+灌浆期、抽穗期+灌浆期水分亏缺处理冬小麦干物质和产量均有显著降低,其中返青期+拔节期、拔节期+抽穗期水分亏缺处理冬小麦干物质显著降低了17.44%,17.57%,产量显著降低了11.60%和14.52%,水分利用效率显著降低了8.02%和7.56%,且对有效穗数、穗粒数也有显著降低作用。施氮对冬小麦产量和水分利用效率有显著促进作用。中氮处理(0.3 g/kg,N2)冬小麦产量最高,耗水量较低,水分利用效率较高。【结论】冬小麦对拔节期、抽穗期、返青期+拔节期、拔节期+抽穗期水分亏缺很敏感,中氮处理具有最高的产量和较高的水分利用效率。     

秸秆还田配施氮肥对冬小麦产量及氮素调控的影响

以周麦23为供试材料,采用裂区设计的大田试验研究 了关中地区秸秆还田配施不同氮肥水平 对冬小麦产量及氮素调控的影响。结果表明：相较于单施氮肥处理,秸秆还田配施氮肥处理 冬小麦产量在低施氮量处理时有降低的趋势,在高施氮量处理时有增加的趋势,但两者间的 差异不显著;秸秆还田配施氮肥能有效提高冬小麦的氮素利用效率,冬小麦的氮肥表观利用 率提高了1.6%～9.1%;秸秆还田措施配施适量的氮肥有降低冬小麦百公斤籽粒需氮量的趋势 。综合考虑到生产成本及潜在环境污染的可能性因素,在秸秆还田条件下,试验地区冬小 麦施氮量以252～321 kg·hm^-2为宜。     

施氮对秸秆还田冬小麦产量和水分利用率的影响

【目的】探讨玉米秸秆还田配施氮肥对关中灌区冬小麦产量和水分利用效率的影响,为该地区实现小麦高产提供理论依据。【方法】以"西农979"作为供试冬小麦品种,研究玉米秸秆还田条件下配施0,87.5,175,262.5,350kg/hm2氮肥以及秸秆不还田条件下施用175kg/hm2氮肥6个处理,对冬小麦产量、土壤贮水量和水分利用率的影响。【结果】在氮肥用量相等(175kg/hm2)的情况下,玉米秸秆还田配施氮肥处理的冬小麦有效穗数、穗粒数、千粒质量和产量较单施氮肥处理分别增加了39万穗/hm2,1.57,2.11g和1 200kg/hm2。6个处理中,玉米秸秆还田配施262.5kg/hm2氮肥处理的冬小麦产量和水分利用率最高,分别达到8 415kg/hm2和20.9kg/(hm2.mm)。各秸秆还田配施氮肥处理的水分利用率明显高于不施氮处理。在氮肥用量相同的情况下,玉米秸秆还田处理耗水量比秸秆不还田处理减少19.00mm。【结论】秸秆还田能提高冬小麦产量和水分利用率,在玉米秸秆还田条件下,关中平原冬小麦氮肥用量应控制在175～262.5kg/hm2。     

不同肥力下生育后期干旱对冬小麦产量及水分利用效率的影响

采用防雨棚下池栽试验,研究了不同肥力下冬小麦生育后期水分亏缺对冬小麦产量及水分利用效率的影响.结果表明,冬小麦干物质积累量、千粒重、穗数、穗粒数、产量均随土壤肥力和含水量的提高而呈增加的趋势,且与全生育期充分灌溉相比,各干旱胁迫处理的干物质积累量、千粒重、穗数、穗粒数、产量的降幅均随土壤肥力的提高而减小,其中土壤水分含...     

黄淮麦区种植密度对晚播冬小麦花后氮素代谢和利用率的影响

【目的】研究种植密度对晚播冬小麦氮素同化、分配及其利用效率的影响,为黄河流域晚播冬小麦的高产和氮肥高效利用提供参考依据。【方法】以"新麦18"为材料,研究了低(150万株/hm2)、中(225万株/hm2)、高(300万株/hm2)3个种植密度对适度晚播(10-26)冬小麦花后氮素代谢和氮素利用的影响。【结果】与正常播期(10-15)冬小麦相比,晚播冬小麦旗叶硝酸还原酶活性和可溶性蛋白含量较高,但因生育期缩短,其全株氮素积累量、籽粒含氮量、产量和氮素利用效率均有所降低。晚播冬小麦中、高密度处理旗叶的硝酸还原酶和谷氨酰胺合成酶活性及旗叶可溶性蛋白含量较高,且中密度处理叶片含氮量、籽粒和全株氮素积累量较高。最终,中、高密度处理的籽粒产量和氮素利用效率高于低密度处理。【结论】在本试验条件下,"新麦18"在适度晚播条件下兼顾高产和高效利用氮素的适宜播种密度为225万株/hm2。     

有机无机复混肥对冬小麦产量及其水分利用效率的影响

对农业废弃物采用生物发酵腐解,进行无害化、矿化和腐殖化处理,经干燥后添加一定比例的化肥以调节养分,加入成粒剂制成颗粒状有机无机复混肥。对获得的有机无机复混肥进行冬小麦田间试验,结果表明,有机无机复混肥可以促进冬小麦分蘖,改善冬小麦产量结构,提高冬小麦产量756.0～901.5kg/hm2;还可降低冬小麦耗水系数,提高冬小麦水分利用效率1.311～1.675kg/(mm·hm2)。     

种植密度对晚播冬小麦氮素同化积累分配及利用效率的影响

研究了种植密度对晚播小麦氮素同化积累分配及氮素利用效率的影响。以重穗型冬小麦品种兰考矮早八为材料,在晚播期(10-24—10-26)设低(150万株/hm2)、中(225万株/hm2)、高(300万株/hm2)3个种植密度进行了2年大田试验。传统播期(10-10—10-12)为对照。结果表明,晚播小麦旗叶的硝酸还原酶活性和可溶性蛋白含量显著提高,单茎氮素积累量、营养器官转移氮素对籽粒氮素积累的贡献率以及植株的氮素收获指数和氮素吸收效率均提高,而氮素利用效率和籽粒产量降低。对照播期的低、中密度处理的氮代谢酶活性、氮素积累量和氮素利用效率及籽粒产量较高,而晚播处理则以中、高密度处理较高。不同播期的中密度处理的蛋白质含量和籽粒产量高于其他2个密度处理。因此,晚播条件下兰考矮早八兼顾高产和高效利用氮素的适宜播种密度为225~300万株/hm2。     

有机无机肥配施对小麦产量及氮肥利用效率的影响

研究了有机肥与无机肥不同配施处理对小麦产量及氮肥利用效率的影响。结果表明,习惯施肥处理(CK)小麦长势最佳,产量达7 451.96 kg/hm~2,比不施肥处理(T0)高121.89%,但氮肥回收利用率(NRE)偏低(30.70%)。氮磷钾肥均减量20%,梯度配施3 750、7 500、11 250、15 000 kg/hm~2有机肥,小麦产量分别为:6 416.72、6 578.70、6 780.71、6 770.88 kg/hm~2;NRE分别为24.30%、36.87%、44.42%、13.40%,小麦产量和NRE均随有机肥施入量呈先增加后降低趋势。不施氮肥,磷钾肥分别减量20%梯度配施有机肥,小麦产量在4 079.37～4 940.60 kg/hm~2之间,显著低于CK、氮磷钾肥减量20%有机肥配施组(P0.05),NRE值(4.37%～72.71%)变幅较大且无规律。合理配施化肥与有机肥,可以维持小麦产量,降低化肥施用量,提高氮肥利用率。     

Effects of water application uniformity using a center pivot on winter wheat yield,water and nitrogen use efficiency in the North China Plain

In recent years, the use of fertigation technology with center pivot irrigation systems has increased rapidly in the North China Plain(NCP). The combined effects of water and nitrogen application uniformity on the grain yield, water use efficiency(WUE) and nitrogen use efficiency(NUE) have become a research hotspot. In this study, a two-year field experiment was conducted during the winter wheat growing season in 2016–2018 to evaluate the water application uniformity of a center pivot with two low pressure sprinklers(the R3000 sprinklers were installed in the first span, the corresponding treatment was RS; the D3000 sprinklers were installed in the second span, the corresponding treatment was DS) and a P85 A impact sprinkler as the end gun(the corresponding treatment was EG), and to analyze its effects on grain yield, WUE and NUE. The results showed that the water application uniformity coefficients of R3000, D3000 and P85 A along the radial direction of the pivot(CU_H) were 87.5, 79.5 and 65%, respectively. While the uniformity coefficients along the traveling direction of the pivot(CU_C) were all higher than 85%. The effects of water application uniformity of the R3000 and D3000 sprinklers on grain yield were not significant(P0.05); however, the average grain yield of EG was significantly lower(P0.05) than those of RS and DS, by 9.4 and 11.1% during two growing seasons, respectively. The coefficients of variation(CV) of the grain yield had a negative correlation with the uniformity coefficient. The CV of WUE was more strongly affected by the water application uniformity, compared with the WUE value, among the three treatments. The NUE of RS was higher than those of DS and EG by about 6.1 and 4.8%, respectively, but there were no significant differences in NUE among the three treatments during the two growing seasons. Although the CU_H of the D3000 sprinklers was lower than that of the R3000, it had only limited effects on the grain yield, WUE and NUE. However, the cost of D3000 sprinklers is lower than that of R3000 sprinklers. Therefore, the D3000 sprinklers are recommended for winter wheat irrigation and fertigation in the NCP.     

Integrated management strategy for improving the grain yield and nitrogen-use efficiency of winter wheat

Understanding of how combinations of agronomic options can be used to improve the grain yield and nitrogen use efficiency(NUE) of winter wheat is limited. A three-year experiment involving four integrated management strategies was conducted from 2013 to 2015 in Tai'an, Shandong Province, China, to evaluate changes in grain yield and NUE. The integrated management treatments were as follows: current practice(T1); improvement of current practice(T2); high-yield management(T3), which aimed to maximize grain yield regardless of the cost of resource inputs; and integrated soil and crop system management(T4) with a higher seeding rate, delayed sowing date, and optimized nutrient management. Seeding rates increased by 75 seeds m~(–2) with each treatment from T1(225 seeds m~(–2)) to T4(450 seeds m~(–2)). The sowing dates were delayed from T1(5 th Oct.) to T2 and T3(8 th Oct.), and to T4 treatment(12 th Oct.). T1, T2, T3, and T4 received 315, 210, 315, and 240 kg N ha~(–1), 120, 90, 210 and 120 kg P_2O_5 ha~(–1), 30, 75, 90, and 45 kg K_2O ha~(–1), respectively. The ratio of basal application to topdressing for T1, T2, T3, and T4 was 6:4, 5:5, 4:6, and 4:6, respectively, with the N topdressing applied at regreening for T1 and at jointing stage for T2, T3, and T4. The P fertilizers in all treatments were applied as basal fertilizer. The K fertilizer for T1 and T2 was applied as basal fertilizer while the ratio of basal application to topdressing(at jointing stage) of K fertilizer for both T3 and T4 was 6:4. T1, T2, T3, and T4 were irrigated five, four, four and three times, respectively. Treatment T3 produced the highest grain yield among all treatments over three years and the average yield was 9 277.96 kg ha~(–1). Grain yield averaged across three years with the T4 treatment(8 892.93 kg ha~(–1)) was 95.85% of that with T3 and was 21.72 and 6.10% higher than that with T1(7 305.95 kg ha~(–1)) and T2(8 381.41 kg ha~(–1)), respectively. Treatment T2 produced the highest NUE of all the integrated treatments. The NUE with T4 was 95.36% of that with T2 and was 51.91 and 25.62% higher than that with T1 and T3, respectively. The N uptake efficiency(UPE) averaged across three years with T4 was 50.75 and 16.62% higher than that with T1and T3, respectively. The N utilization efficiency(UTE) averaged across three years with T4 was 7.74% higher than that with T3. The increased UPE with T4 compared with T3 could be attributed mostly to the lower available N in T4, while the increased UTE with T4 was mainly due to the highest N harvest index and low grain N concentration, which consequently led to improved NUE. The net profit for T4 was the highest among four treatments and was 174.94, 22.27, and 28.10% higher than that for T1, T2, and T3, respectively. Therefore, the T4 treatment should be a recommendable management strategy to obtain high grain yield, high NUE, and high economic benefits in the target region, although further improvements of NUE are required.     

Effects of deep vertical rotary tillage on the grain yield and resource use efficiency of winter wheat in the Huang-Huai-Hai Plain of China

Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFP_N),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFP_N and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFP_N and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.     

Yield and water use responses of winter wheat to irrigation and nitrogen application in the North China Plain

With increasing water shortage resources and extravagant nitrogen application, there is an urgent need to optimize irrigation regimes and nitrogen management for winter wheat(Triticum aestivum L.) in the North China Plain(NCP). A 4-year field experiment was conducted to evaluate the effect of three irrigation levels(W1, irrigation once at jointing stage; W2, irrigation once at jointing and once at heading stage; W3, irrigation once at jointing, once at heading, and once at filling stage; 60 mm each irrigation) and four N fertilizer rates(N0, 0; N1, 100 kg N ha~(-1); N2, 200 kg N ha~(-1); N3, 300 kg N ha~(-1)) on wheat yield, water use efficiency, fertilizer agronomic efficiency, and economic benefits. The results showed that wheat yield under W2 condition was similar to that under W3, and greater than that under W1 at the same nitrogen level. Yield with the N1 treatment was higher than that with the N0 treatment, but not significantly different from that obtained with the N2 and N3 treatments. The W2 N1 treatment resulted in the highest water use and fertilizer agronomic efficiencies. Compared with local traditional practice(W3 N3), the net income and output-input ratio of W2 N1 were greater by 12.3 and 19.5%, respectively. These findings suggest that two irrigation events of 60 mm each coupled with application of 100 kg N ha~(–1) is sufficient to provide a high wheat yield during drought growing seasons in the NCP.     

Canopy morphological changes and water use efficiency in winter wheat under different irrigation treatments

Water is a key limiting factor in agriculture. Water resource shortages have become a serious threat to global food security. The development of water-saving irrigation techniques based on crop requirements is an important strategy to resolve water scarcity in arid and semi-arid regions. In this study, field experiments with winter wheat were performed at Wuqiao Experiment Station, China Agricultural University in two growing seasons in 2013–2015 to help develop such techniques. Three irrigation treatments were tested: no-irrigation(i.e., no water applied after sowing), limited-irrigation(i.e., 60 mm of water applied at jointing), and sufficient-irrigation(i.e., a total of 180 mm of water applied with 60 mm at turning green, jointing and anthesis stages, respectively). Leaf area index(LAI), light transmittance(LT), leaf angle(LA), transpiration rate(Tr), specific leaf weight, water use efficiency(WUE), and grain yield of winter wheat were measured. The highest WUE of wheat in the irrigated treatments was found under limited-irrigation and grain yield was only reduced by a small amount in this treatment compared to the sufficient irrigation treatment. The LAI and LA of wheat plants was lower under limited irrigation than sufficient irrigation, but canopy LT was greater. Moreover, the specific leaf weight of winter wheat was significantly lower under sufficient than limited irrigation conditions, while the leaf Tr was significantly higher. Correlation analysis showed that the increased LAI was associated with an increase in the leaf Tr, but the specific leaf weight had the opposite relationship with transpiration. Optimum WUE occurred over a reasonable range in leaf Tr. In conclusion, reduced irrigation can optimize wheat canopies and regulate water consumption, with only small reductions in final yield, ultimately leading to higher wheat WUE and water saving in arid and semi-arid regions.     

Growth and nitrogen productivity of drip-irrigated winter wheat under different nitrogen fertigation strategies in the North China Plain

Excessive application of nitrogen (N) fertilizer is the main cause of N loss and poor use efficiency in winter wheat (Triticum aestivum L.) production in the North China Plain (NCP).  Drip fertigation is considered to be an effective method for improving N use efficiency and reducing losses, while the performance of drip fertigation in winter wheat is limited by poor N scheduling.  A two-year field experiment was conducted to evaluate the growth, development and yield of drip-fertigated winter wheat under different split urea (46% N, 240 kg ha^–1) applications.  The six treatments consisted of five fertigation N application scheduling programs and one slow-release fertilizer (SRF) application.  The five N scheduling treatments were N0–100 (0% at sowing and 100% at jointing/booting), N25–75 (25% at sowing and 75% at jointing and booting), N50–50 (50% at sowing and 50% at jointing/booting), N75–25 (75% at sowing and 25 at jointing/booting), and N100–0 (100% at sowing and 0% at jointing/booting).  The SRF (43% N, 240 kg ha^–1) was only used as fertilizer at sowing.  Split N application significantly (P<0.05) affected wheat grain yield, yield components, aboveground biomass (ABM), water use efficiency (WUE) and nitrogen partial factor productivity (NPFP).  The N50–50 and SRF treatments respectively had the highest yield (8.84 and 8.85 t ha^–1), ABM (20.67 and 20.83 t ha^–1), WUE (2.28 and 2.17 kg m^–3) and NPFP (36.82 and 36.88 kg kg^–1).  This work provided substantial evidence that urea-N applied in equal splits between basal and topdressing doses compete economically with the highly expensive SRF for fertilization of winter wheat crops.  Although the single-dose SRF could reduce labor costs involved with the traditional method of manual spreading, the drip fertigation system used in this study with the N50–50 treatment provides an option for farmers to maintain wheat production in the NCP.     

不同有机养分替代化肥对小麦产量、氮肥利用率及土壤肥力的影响

为探究有机肥种类和替代比例对小麦产量、氮肥利用率及土壤肥力的影响,通过田间小区试验,设置不施肥（CK）,常规施肥（CN）,优化减量施肥（ON）,优化减量配施15%(ONL-15%)、30%(ONL-30%)和50%(ONL-50%)沼液氮,优化减量配施30%堆肥氮（ONC-30%）,优化减量配施30%商品有机肥氮（ONS-30%）共8个处理。结果表明：与CN处理相比,ON、ONL-15%和ONL-30%处理均显著增加小麦籽粒产量和氮肥利用率,其中ONL-15%处理小麦产量最高,较CN和ON处理分别增产16.18%和14.08%,该处理下氮肥利用率也由CN处理的18.41%增至36.46%,表明优化减量配施15%沼液氮肥为减氮配施沼液最佳比例。在30%替代比例下,不同种类有机肥配施对小麦增产效果存在差异,与ON处理相比,沼液配施增加小麦产量和氮肥利用率,而堆肥和商品有机肥配施显著降低小麦产量。堆肥配施可以促进土壤全氮、水解性氮和有效磷的积累,商品有机肥配施对缓解土壤酸化、增加土壤有机质含量具有较好效果。有机无机配施处理减少32.60%～65.91%硝态氮在耕层土壤的残留,增加土壤有效氮含...     

Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat

Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.     

氮利用率和氮转化率评价氮肥肥效比较研究

基于生态平衡施肥理论和通用施肥模型,以河南省小麦氮肥肥效试验数据为例,分别求算长期定位试验、普通田间试验、示踪试验三种情况下的肥料氮利用率和氮转化率,并进行评价,结果表明:①长期定位试验氮利用率和氮转化率都比较稳定;普通田间试验在最佳施氮情况下,氮利用率和氮转化率均与长期定位试验结果接近,但不同普通田间试验之间氮利用率变幅较大;示踪试验的氮利用率或氮转化率不能作为评价肥效和指导施肥的科学依据;②氮利用率低估了氮肥肥效;不考虑外源氮时则高估了氮肥肥效;使用氮转化率和外源氮是科学评价氮肥肥效的方法;③具体施肥实践时,可以不考虑外源氮而直接使用氮相对转化率评价肥效和指导施肥;参照长期定位试验的最佳施氮量,即使在不测定土壤氮的情况下也可以使用氮转化率半定量地指导施肥。     

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。     

氮素对冬小麦产量的亏缺及补偿效应

通过盆栽试验研究了正常灌水条件下，不同生育阶段氮素亏缺对冬小麦生长发育的影响。结果表明，越冬期和拔节期氮素亏缺对冬小麦的产量影响最大，后期缺氮对其产量的影响最小。总的来看，冬小麦对氮素的亏缺敏感期在越冬期和拔节期，尤以拔节期更为迫切；补偿有效期在拔节期。