Integrated agronomic practice increases maize grain yield and nitrogen use efficiency under various soil fertility conditions

Crop yield potential can be increased through the use of appropriate agronomic practices. Integrated agronomic practice (IAP) is an effective way to increase maize (Zea mays L.) grain yield and nitrogen use efficiency (NUE);however, the physiological processes associated with gains in yield potential obtained from IAP, particularly the different under various soil fertility conditions, remain poorly understood. An IAP strategy including optimal planting density, split fertilizer application, and subsoiling tillage was evaluated over two growing seasons to determine whether the effects of IAP on maize yield and NUE differ under different levels of soil fertility. Compared to farmers' practices (FP), IAP increased maize grain yield in 2013 and 2014 by 25% and 28%, respectively, in low soil fertility (LSF) fields and by 36% and 37%, respectively, in high soil fertility (HSF) fields. The large yield gap was attributed mainly to greater dry matter (DM) and N accumulation with IAP than with FP owing to increased leaf area index (LAI) and DM accumulation rate, which were promoted by greater soil mineral N content (Nmin) and root length. Post-silking DM and N accumulation were also greater with IAP than with FP under HSF conditions, accounting for 60% and 43%, respectively, of total biomass and N accumulation;however, no significant differences were found for post-silking DM and N accumulation between IAP and FP under LSF conditions. Thus, the increase in grain yield with IAP was greater under HSF than under LSF. Because of greater grain yield and N uptake, IAP significantly increased N partial factor productivity, agronomic N efficiency, N recovery efficiency, and physiological efficiency of applied N compared to FP, particularly in the HSF fields. These results indicate that considerable further increases in yield and NUE can be obtained by increasing effective soil N content and maize root length to promote post-silking N and DM accumulation in maize planted at high plant density, especially in fields with low soil fertility.

Effects of Gel-based Controlled Release Fertilizers on Agronomic Characteristics and Physiological Indices of Corn

[Objective] This study aimed to investigate the effects of gel-based controlled release fertilizers （CRFs） on agronomic characteristics and physiological indices of corn. [Method] Pot experiment was carried out to investigate the agronomic characteristics and physiological indices of corn fertilized with controlled release fertilizers compared with conventional fertilizer （CF）. [Result] Plant height, stem girth, leaf area and root volume of corn were significantly increased under the CRF treatments; photosynthetic rate and soluble protein content were also improved. Dry matter accumulations under the two CRF treatments were increased by 21.3% and 17.0% compared with CF application at one time （CF1）, and 19.6% and 15.4% with CF application at two times （CF2）, respectively. Accumulation amounts of N, P and K in whole plant under the two CRF treatments were increased by 44.0% -24.7% , 40.0%-25.9% and 20.1% -13.9% ; and the nutrient use efficiencies of N, P and K were improved by 22.9% -13.4% , 11.2% -9.6% and 17.5% -12.1% , respectively. [Conclusion] The results implied that the CRFs could significantly improve nutrient use efficiency and plant yield.

Experimental Study to Improve the Agronomic Efficiency of Low Grade Fine Size Rock Phosphate

Soluble phosphate fertilizers have been preferably used in plant crop production. The cost of applying conventional water soluble phosphate fertilizer is high in developing countries since their manufacturing requires importing high grade rock phosphate （RP）. As a result, the use of indigenously available low-grade RP is gaining importance globally. In this study, experiments were carried out using clayey loamy alkaline soil to evaluate the agronomic efficiency of fine sized low grade RP with inorganic nitrogen fertilizers and it was further compared with that of soluble phosphate fertilizer （di-ammonium phosphate）, Cicer arietinum was the test crops subjected to treatments of absolute control, di-ammonium phosphate and low grade RP with varying concentrations of ammonium sulphate or ammonium nitrate. The experiments were conducted during 2012-2013 in the bid to study the growth rate and the biomass of the crop. Tests were also performed to determine the residual effects of the fertilizers on the crops. The results revealed that the combined use of low grade RP and ammonium sulphate or ammonium nitrate, at 16 kg N/ha, resulted in an agronomic efficiency, in terms of biomass of plants, comparable to that of di-ammonium phosphate and was found to be a more attractive management option for resource-poor farmers.

Agronomic cultivation measures on productivity of oilseed flax:A review

Oilseed flax is one of the most important oil crops in China.With the improvement of people's living standards and the deepening knowledge of the nutritional value of oilseed flax,the demand and economic value of oilseed flax are increasing,and the cultivated area in China is expanding.However,the grain yield of oilseed flax is lower than other oil crops.It varies significantly from year to year,combined with a lower degree of mechanization,which has greatly limited the healthy development of the flax industry.Some of the effects of agronomic measures on productivity and water use efficiency of oilseed flax are reviewed in this paper.The major agronomic strategies for the productivity of oilseed flax were presented based on fertilization,plant density,irrigation,cropping pattern and weed control.Future research should investigate the effect of silicon and potassium fertilizers on the mechanism of lodging resistance of oilseed flax,the effects of diversified cropping systems(strip intercropping and crop rotation)on high and stable productivity and efficient utilization of resources.

Optimizing Fertilizer Use by Smallholder Farmers and Economic Returns to Maize in Semi-arid Niger

Maize （Zea mays L.） is an important food crop in Niger, but low and irregular rainfall combined with sandy soils having low fertility level limit productivity. A two-year study was conducted at Institut National de Recherche Agronomique du Niger （INRAN） stations in Tarna/Maradi and Bengou/Gaya in 2014 and 2015 in order to evaluate maize agronomic and economic fertilizer use efficiency. The experimental design was a randomised complete block design （RCBD） with three replications. Results indicate higher effect of fertilizer in 2015 compared to 2014. At low N rates 20 kg N/ha and 40 kg N/ha, application of 20 kg P/ha increased maize grain yield across locations and years. The highest agronomic efficiency of N （AEN） was recorded with 60 kg N/ha in 2015 at Bengou and Tarna with 9.65 kg and 14.05 kg grain yield per kg of applied N, respectively. At Tarna, the low N rates of 20 kg N/ha and 40 kg N/ha recorded important AEN of more than 12 kg yield increases per kg of applied N. The highest rainfall use efficiency （RUE） of 6.13 kg/year/mm was obtained with application of 80 kg/ha N, 0 kg/ha P and 40 kg/ha N, 20 kg/ha P in 2015 at Tarna. Without P, the highest value cost ratio （VCR） value of 4.31 was recorded at Tarna in 2015 with 60 kg/ha N, and the lowest value of 0.08 at Bengou in 2014 with 20 kg/ha N. Based on VCR and RUE derived from this study, the optimal fertilizer recommendation for maize in the semi-arid conditions of Niger could be 40 kg/ha N, 20 kg/ha P and 0 kg/ha K.

Optimizing N fertilizer use for sesame under rain fed and irrigation conditions in Northern Ethiopia

Inappropriate use of fertilizers is one of the major production constraints in sesame. Studies on N fertilizer optimization on sesame were conducted at Humera Agricultural Research Center(Hu ARC) under rain fed and irrigation conditions. Thirteen(13) N doses were evaluated in a Randomized Complete Block Design(RCBD)during 2016–2018 for rainfed conditions and 2017 to 2019 for irrigation conditions. The study was conducted with objective to optimize N fertilizer use for sesame. In the rainfed condition, the results demonstrated a prolonged duration to reach 50% flowering with higher nitrogen(N) application rates. The application of 52.5–110kg N ha^(-1) resulted in significantly higher seed yield, while lower(18 kg N ha^(-1)) and higher(156 kg N ha^(-1)) doses of N led to reduced seed yield. Under irrigation conditions, superior seed weights and maximum seed yield were observed at 64 and 75 kg N ha^(-1), whereas lower N doses resulted in diminished seed yield. The agronomic efficiency of N fertilizer(N-AE) was found to be highest at the rate of 64 kg N ha^(-1) under both growing conditions.The partial budget analysis revealed that applying 64 kg N ha^(-1) for rainfed cultivation and between 64 and 75 kg N ha^(-1) for irrigated sesame production yielded greater net profit, MRR, and residual ranking. Therefore, it is recommended to apply a rate of 64 kg N ha^(-1) for rainfed sesame cultivation and between 64 up to 75 kg N ha^(-1) for the irrigated sesame inorder to increase the productivity of this crop.

Economically Optimal Rates and Nutrients Use Efficiency Indices of Maize to the Application of Different Rates of Nutrients in Central Rift Valley of Ethiopia

The use of balanced fertilizers in adequate amount is very important to increase crop productivity and production in Ethiopia. The study was executed to quantify maize (Zea mays L.) grain yield response to different rates of nitrogen (N), phosphorus (P), potassium (K) and sulfur (S) under balanced fertilization of other nutrients. On farm trials were conducted at seven sites on 8 farmers’ fields in Negele Arsi districts, west Arsi zone of Oromia region for three consecutive cropping seasons (2014-2016). Six rates of N, P, S and eight rates of K treatments established separately for each nutrient were laid out in randomized complete block (RCB) design with three replicates per farm. Nutrient response function modelling showed that 184, 20 and 80 kg•ha−1 were the agronomic optimum rate for N, P, and K, respectively. Mean agronomic efficiency (AE) of N, P and K were recorded at the lower rates of these nutrients, application of 46, 10 and 20 kg•ha−1 N, P and K resulted in 19.1, 61.0, and 24 kg additional grain yield•kg−1 N, P and K, respectively. Also, the mean partial factor productivity (PFP) of N, P and K were 77.6, 370 and 158 kg additional grain•kg−1 applied N, P and K respectively. Economically optimal rate (EOR) of N, P and K were 48 - 114 kg•ha−1 N with CP 8 - 3.5, 12 - 20 kg•ha−1 P with CP 18 - 4.5 and 32 - 53 kg•ha−1 K with CP 8-4, from these rates net returns of US$487.23 - 143.30, US$698.16 - 498.3 and US$359.31 - 193.63 could be obtained respectively. To conclude, application of 84, 12 and 40 kg•ha−1 N, P and K could be recommended for the production of maize.

推荐施肥量下控释肥替代普通尿素提高高粱产量和氮肥生产力

【目的】高粱生产中氮肥施用不合理,氮肥利用效率低,研究适宜重庆地区高粱种植的控释氮肥减施比例,在减少氮肥用量的同时,确保高粱稳产高产,提高肥料利用效率。【方法】田间定位试验于2021、2022年在重庆永川进行,供试高粱品种为晋渝糯3号和金糯粱1号。设置6个处理,分别为不施氮肥(CK);习惯尿素施肥量(U,N 180 kg/hm^(2));尿素推荐施用量(U1,减N 20%,N 144 kg/hm^(2));控释氮肥减施氮量20%(C1,N144 kg/hm^(2));控释氮肥减施氮量30%(C2,N 126 kg/hm^(2));控释氮肥减施氮量40%(C3,N 108 kg/hm^(2))。在高粱开花期和成熟期,调查干物质积累量和转运量,成熟期调查植株和籽粒氮素含量、生物量、产量及产量构成因素。【结果】开花期和成熟期高粱干物质积累量均以C1和U1处理最高,C1处理成熟期干物质积累量又显著高于U1。C1处理叶片花前干物质转运量显著高于U。花后干物质积累量C1处理显著高于其他处理,U1和C2处理显著高于U处理。C1处理晋渝糯3号和金糯粱1号花后干物质积累量对籽粒的贡献率较U分别显著提高了11.54%和12.41%。C1处理的高粱产量最高(晋渝糯3号6611 kg/hm^(2),金糯粱1号5690 kg/hm^(2)),较其他施氮处理显著提高了5.40%~18.66%;其次为C2和U1处理,二者的产量均显著高于U和C3处理。各施氮处理的氮肥生理利用率(NPE)差异不显著;减氮处理间氮肥农学利用率(NAE)无显著差异,氮肥偏生产力(NPFP)差异显著,其NAE和NPFP均显著高于习惯施氮处理U;控释肥各减氮处理的NPFP显著高于普通氮肥推荐量处理U1。C1处理较U处理大幅提高了NAE、NPFP和氮肥利用率(NUE),晋渝糯3号分别提高了58.54%、39.61%和59.28%,金糯粱1号分别提高了80.97%、48.30%和63.08%;与U1处理相比,晋渝糯3号的NPFP、NUE分别提高了5.38%和22.19%,金糯粱1号分别提高了5.82%和4.42%。【结论】推荐施氮量下,用控释肥替代普通氮肥增加了高粱开花期和成熟期干物质积累量,提高了叶片花前干物质转运量和花后干物质积累量及其对籽粒的贡献率,提升了高粱产量和氮肥利用效率,可作为西南地区高粱生产的推荐氮肥施用方式。

高粱杂交种氮高效利用综合评价

为从华北、东北高粱主产区筛选出适应当地生态条件、氮利用效率更高的优质高产高粱品种,以20份国内主推高粱品种为试验材料,采用裂区试验设计,研究供试品种在不同地点的氮肥农学效率和氮肥偏生产力表现。本研究旨在筛选出适宜当地生产的氮高效高粱品种。研究结果表明:基于粱氮素农学利用率和偏生产力,将20个高粱品种分为氮高效型、氮中效型和氮低效型3类,与氮中效型和低效型品种相比,氮高效型品种具有较高的产量。聚类分析表明,在东阳地区试验中,‘晋杂34’、‘辽糯11’、‘吉杂124’、‘晋早5564’和‘金糯粮5’在2年均为氮高效型品种,其中以‘晋杂34’表现最好。在哈尔滨地区试验中,‘龙杂22’、‘龙杂25’、‘沈杂5号’、‘冀酿3号’、‘凤杂4’、‘吉杂124’、‘吉杂127’、‘辽杂37’、‘晋早5564’、‘通杂108’和‘赤杂107’在2年均为氮高效型品种,其中以‘龙杂25’表现最好。因此,东阳地区较为适宜种植的氮高效品种为‘晋杂34’,哈尔滨地区较为适宜种植的氮高效品种为‘龙杂25’。

优化施肥对水稻产量和肥料利用率的影响

依据水稻养分吸收规律,通过设置优化施肥处理组、常规施肥处理组和氮、磷、钾减素处理组,比较了不同处理下水稻产量、养分积累量、肥料偏生产力、肥料农学效率和回收利用率等差异。结果表明:除减氮处理外,其他处理间水稻产量无显著性差异。与常规施肥处理相比,优化施肥处理的水稻产量提高了1.7%,其氮肥、磷肥和钾肥的农学效率分别提高了53.89%、248.02%和34.88%,氮肥、磷肥和钾肥的回收利用率分别提高了14.89%、138.07%和19.60%。结合土壤中的养分含量,发现青浦区土壤中的磷、钾含量较高,氮肥农学效率和回收利用率均低全国平均水平。基于作物养分吸收规律,采用缓释肥料替代传统肥料并减少肥料施用量,是保障水稻产量并提高养分利用率、减少养分流失的重要手段。

沼液不同施用量对水芹生长发育与田面水氮素排放的影响

【目的】探明沼液不同施用量对水芹生长发育与田面水氮素排放的影响,筛选适宜的沼液量与化肥配比,为化肥减量和沼液的资源化利用提供参考。【方法】以宜兴实心芹为研究对象,采用盆栽试验,研究不施肥(CK)、常规施肥(N_(0))、沼液50%替代化肥(N_(50))和沼液100%替代化肥(N_(100))对水芹生长发育、田面水总氮和铵态氮浓度及氮素利用率的影响。【结果】不同施肥处理水芹的生长状况、营养品质、田面水的总氮和铵态氮浓度及氮素利用率不同。沼液50%替代化肥处理可显著提高水芹茎鲜重、叶鲜重、地上部鲜重和株高,分别为46.68 g/Pot、16.20 g/Pot、64.23 g/Pot和49.53 cm;增加茎部和叶部的总叶绿素、类胡萝卜素、维生素C含量,分别为0.21 mg/g FW、0.03 mg/g FW、2.61 mg/100g FW和2.02 mg/g FW、0.31 mg/g FW、28.08 mg/100g FW;硝酸盐含量较常规施肥处理分别显著降低30.52%和48.77%;同时降低了水芹田面水总氮和铵态氮浓度,经2次追肥后分别在11 d和23 d达峰值,为113.14 mg/L和38.49 mg/L;氮肥偏生产力和农学效率均达最大,分别为53.53 kg/kg和12.37 kg/kg。【结论】采用沼液50%替代化肥施用有利于促进水芹生长,提高营养品质,同时降低由降雨等引发的氮素排放风险,可在水芹种植上推广应用。

合理增施有机肥减施化肥对新沂水蜜桃生产的影响

为筛选出适宜新沂地区水蜜桃的最佳有机肥替代化肥比例,研究商品有机肥45 t/hm^(2)施用量下分别减施10%、20%、30%和40%化肥的应用效果,并对水蜜桃的产量和品质进行测定,分析有机肥替代的经济效益和肥料农学效率。结果表明,增施有机肥并减施10%和20%化肥虽然成本较增施有机肥并减施30%和40%高,但产量增加较多,经济效益有所增加,总体经济效益和肥料农学效率提高。有机肥替代化肥均可改善果实品质,可潜在提高经济效益。有机肥替代化肥处理均增加了肥料农学效率,增施有机肥并减施10%和20%化肥对肥料利用效率最佳。

干旱灌区减量灌水下玉米农艺性状、产量及水肥利用效率对间作绿肥的响应

于2020—2022年采用裂区试验设计,主区设玉米‖箭筈豌豆(M‖V)和单作玉米(SM)2个种植模式,裂区设高量(I3,400 mm)、中量(I2,340 mm)、低量(I1,280 mm)3个灌水水平,探究间作绿肥对减量灌水下玉米农艺性状、产量、土壤全氮含量、水分利用效率(WUE)及氮肥偏生产力(PFPF)的影响。结果表明,与SM相比,M‖V玉米株高、茎粗、穗位高分别增加6.3%~14.3%、5.4%~12.0%和12.5%~22.1%,玉米穗长、穗粗、穗行数、行粒数分别增加5.7%~20.2%、3.7%~13.6%、2.7%~5.9%和6.8%~17.7%;间作模式下,M‖VI2与M‖VI3处理间玉米株高、茎粗、穗位高、穗长、穗粗、穗行数、行粒数差异不显著,各指标分别较M‖VI1处理显著增加6.7%~7.7%、4.9%~5.8%、7.7%~11.6%、6.2%~11.3%、2.0%~5.1%、1.0%~2.0%和5.2%~10.3%。M‖V较SM玉米增产效果显著,籽粒产量和生物产量分别提高7.7%~27.9%和5.7%~19.2%;间作模式下,M‖VI2与M‖VI3处理间玉米籽粒产量及生物产量无显著差异,两指标分别较M‖VI1处理显著增加5.7%~15.5%和4.7%~8.0%。M‖V较SM显著增加了0~40 cm土层土壤全氮含量、WUE和PFPF,增幅分别为5.8%~7.9%、12.4%~28.3%和7.7%~27.9%;间作模式下,M‖VI2与M‖VI3处理间PFPF无显著差异,较低灌水处理显著增加5.7%~15.5%,M‖VI2较M‖VI3处理WUE显著增加7.7%~10.8%。相关分析表明,间作箭筈豌豆可通过提升土壤全氮含量改善玉米株高、茎粗、穗位高、穗长、穗粗及穗行数,通过增加穗粒数和千粒重保障中量灌水(340 mm)条件下玉米产量不降低,从而提高水肥利用效率。因此,间作箭筈豌豆结合灌水340 mm可作为河西灌区水资源承载安全范围内的玉米间作绿肥高效生产模式。

施用有机肥和秸秆还田对旱地玉-麦二熟体系作物产量、品质和化肥效率的影响

为探明施用商品有机肥和秸秆还田对旱地夏玉米-冬小麦二熟体系作物产量、品质和肥料利用效率的影响,于2015—2020年度设置不施肥+秸秆不还田(CK)、施氮磷肥+秸秆不还田(NP)、施氮磷肥+秸秆不还田+商品有机肥(NPO)和施氮磷肥+秸秆还田(NPS)4个处理进行田间试验,测定并分析作物产量、氮磷肥农学效率、籽粒养分含量、蛋白质含量以及冬小麦籽粒中蛋白质组分含量。结果表明:(1)与NP和NPO处理相比,NPS处理夏玉米5 a平均产量分别显著提高21.33%和20.77%,周年产量分别显著提高9.99%和13.43%,但3个施肥处理间小麦产量差异不显著。(2)施用商品有机肥和秸秆还田对夏玉米、冬小麦的籽粒品质均有显著影响。与NP处理相比,NPO处理冬小麦籽粒各蛋白质组分含量提高5.69%~8.28%;NPS处理冬小麦籽粒氮含量、钾含量和各蛋白质组分含量分别提高4.68%、3.96%和7.75%~11.38%。相较于NPO处理,NPS处理冬小麦籽粒钾含量、谷蛋白含量、贮藏蛋白含量和谷醇比分别显著提高14.41%、9.86%、5.39%和9.65%,夏玉米籽粒蛋白质含量、产量和籽粒氮、籽粒磷含量以及周年蛋白质产量分别显著提高6.45%、28.89%、6.40%、23.08%和10.43%。(3)相较于NP和NPO处理,NPS处理夏玉米氮肥的农学效率分别提高118.35%和113.25%,周年氮、磷肥农学效率分别提高42.83%和64.36%、42.86%和64.27%,但3个施肥处理间冬小麦氮肥、磷肥农学效率5 a均值无显著差异。综合来看,长期施用商品有机肥和秸秆还田可改善冬小麦籽粒中的蛋白质组分特性,秸秆还田还能增加夏玉米籽粒钾含量和冬小麦籽粒蛋白质含量和蛋白质产量,秸秆还田较施用商品有机肥更利于提高旱地玉-麦二熟区作物产量、品质和肥料利用效率。综上所述,施氮磷肥+秸秆还田的管理模式更适宜在旱地玉-麦二熟区进行推广。

陇中旱农区不同品种马铃薯水氮利用效率研究

以12个马铃薯品种为研究对象,连续2 a(2022—2023年)设置不施氮(0 kg·hm^(-2))和施氮(180 kg·hm^(-2))2个施氮水平,分析不同品种马铃薯产量和水氮效率特征,并采用隶属函数法对各马铃薯品种进行综合评价。结果表明:品种、氮水平和品种×氮水平都对晚熟马铃薯产量均具有极显著影响,而氮水平×品种对中熟品种无显著影响。连续2 a供氮条件下中熟品种产量变幅为8289.39~22011.61 kg·hm^(-2),晚熟品种产量变幅为8192.57~20308.58 kg·hm^(-2)。基于2 a施氮和不施氮条件下各品种块茎产量,将不同马铃薯品种按照不同氮效率划分为4种类型,即双高型(‘京张薯1号’、‘陇薯20号’、‘青薯9号’、‘陇薯15号’、‘陇薯16号’)、低氮高效型(‘V7’、‘陇薯14号’)、高氮高效型(‘陇薯10号’)和双低型(‘冀张薯12号’、‘希森6号’、‘定薯3号’、‘陇薯22号’)。相关性分析结果表明:氮素吸收效率、氮肥表观利用率与产量呈极显著正相关关系(R^(2)=0.4438**,R^(2)=0.4211**),马铃薯产量与块茎含氮量间呈极显著正相关关系(R^(2)=0.5302**,R^(2)=0.4357**),说明在施氮和不施氮条件下,马铃薯块茎含氮量越高则其产量越高。隶属函数分析结果表明:中熟品种‘京张薯1号’(D i=0.90)、晚熟品种‘青薯9号’(D i=0.90)和‘陇薯10号’(D i=0.87)具有较高的综合水氮效率和产量表现,可作为水氮高效品种在陇中旱作区进行推广。

不同水肥模式对机插稻产量形成和氮肥吸收利用的影响

为阐明机插稻返青活棵-分蘖期不同水肥管理方式对其产量形成和氮肥吸收利用的影响,并提出机插稻返青活棵-分蘖期适宜的水肥管理模式,于2022年以南粳9108和南粳5718为供试品种,在返青活棵-分蘖期设置不同水肥管理方式(水稻返青活棵期多次水分灌排与分蘖期增施氮肥(T1)、水稻返青活棵期多次水分灌排与分蘖期不增施氮肥(T2)、水稻返青活棵期减少灌水不排水且分蘖期不增施氮肥(T3)),对比分析不同水肥管理方式下水稻产量形成和氮肥吸收利用的差异。结果表明,返青活棵-分蘖期不同水肥管理方式对机插稻产量和氮肥吸收利用影响显著。相较于T2处理,T1和T3处理显著增加了水稻产量和氮素积累量,产量分别提高8.2%~9.5%和13.3%~13.7%,成熟期氮素积累量分别提高7.0%~8.8%和12.8%~15.2%(p<0.05)。相较于T1处理,T3处理水稻拔节期茎蘖数降低11.4%~11.9%,茎蘖成穗率显著提高11.3%~12.4%,拔节期叶面积指数和干生物量分别显著降低8.2%~9.3%和6.3%~8.6%,抽穗期-成熟期光合势和群体生长率无显著差异。在产量及其构成因素方面,T1和T3处理间无显著差异(p>0.05)。在氮素吸收利用方面,T1和T3处理在氮素积累量方面无显著差异,但T3处理氮肥农学利用率和氮肥回收利用率较T1分别显著增加20.1%~22.2%和22.7%~23.0%(p<0.05)。综上所述,在分蘖期不增施氮肥的基础上,通过返青活棵期减少灌水和不排水的方式可以实现机插稻产量和氮肥利用率的同步提升。

功能性缓释掺混肥料对玉米产量及土壤氮含量的影响

根据玉米需肥规律开发了功能性缓释掺混肥,为考察其对玉米生长及土壤氮素含量的影响,开展了田间小区试验。试验共设6个处理,以不施肥(CK1)、普通掺混肥(CK2)处理为对照,调查了玉米生物学性状、产量以及玉米收获后土壤中硝态氮、铵态氮、碱解氮含量等指标。结果表明:在等施肥量条件下,功能性缓释掺混肥处理的玉米产量比CK2处理的增产7.98%,差异显著;在功能性缓释掺混肥施用量减少20%的条件下,不会造成玉米减产;功能性缓释掺混肥处理的氮素农学利用率比CK2处理的提高7.98%~26.82%;在等施肥量条件下,功能性缓释掺混肥处理的0~20 cm土层中硝态氮和碱解氮含量比CK2处理的分别提高了10.34%和17.39%,铵态氮含量降低了14.29%。

不同缓释肥料用量及运筹方式对杂交晚稻农艺性状及产量的影响

为筛选出适合晚稻生产的肥料运筹方式,减少肥料成本、增加经济效益,以籼粳杂交晚稻甬优7850为试验材料,研究不同缓释肥料用量及运筹方式对产量、农艺性状及氮素效率的影响。结果表明,等养分处理下,有机无机缓释肥有利于提高有效穗、每穗粒数,667 m^(2)基肥使用30 kg加适量分蘖肥较常规施肥增产4.80%,氮肥农学效率最高;等成本情况下,缓释肥处理氮素减少,产量仍较常规施肥增加1.53%,且氮肥农学效率明显高于常规施肥。双季晚稻有机无机缓释肥以667 m^(2)基肥用量30 kg、总氮量在10.7~12.0 kg为宜。

褐潮土长期定位不同施肥制度土壤生产功能演化研究

通过14年长期定位试验,研究了褐潮土不同施肥制度对土壤生产功能、产量可持续性指数及农学效率的影响.结果表明,N、P为褐潮土作物高产的主要限制因子,14年产量平均,NPK比CK、N、NK、PK分别增产459%、386%、280%、205%（小麦）和154%、108%、87%、78%（玉米）;NPK＋M（NPK配施厩肥）比NPK平均增产12%,NPK＋S（NPK加秸秆）与NPK产量相当.NPK及NPK配施有机肥（包括厩肥和秸秆）处理的小麦、玉米产量可持续性指数高于N、P不均衡施用处理.化肥肥效因作物种类、施肥组合而不同,N肥单施时小麦和玉米N的农学效率降低,而NPK配施时N的农学效率有上升趋势,平均分别为16 kg/kg N（小麦）和14 kg/kg N（玉米）;磷肥肥效具有短期的叠加效应,P的农学效率小麦大于玉米,种植10年后P的农学效率最高可达最初的4.5～7倍;K的农学效率在试验进行10年后NK处理平均为负值,同期NPK处理中小麦K的农学效率却急剧增加,K成为作物高产的限制因素;有机肥对小麦和玉米的农学效率分别为21 kg/t和25kg/t,秸秆对小麦和玉米的农学效率分别为负值和37 kg/t.NPK均衡施肥能提高土壤有机质、全N、全P、速效N、速效P等肥力指标;NPK配施有机肥能加快土壤有机质和N、P、K养分的积累;NPK不均衡施肥导致土壤中此种营养元素的耗竭.

当前生产条件下不同作物施肥效果和肥料贡献率研究

【目的】研究在当前生产条件下化肥施用对不同作物产量的影响,明确化肥对不同作物产量的贡献率及肥料的农学利用率现状。【方法】2006年至2008年在湖北省分别布置水稻、小麦、油菜和棉花的田间肥效试验251、47、62和26个,分析研究氮、磷、钾肥配合施用对农作物的增产效果,以及目前不同作物的肥料贡献率和肥料农学利用率现状。【结果】目前农作物平衡施用氮、磷、钾肥的增产效果显著,但不同作物的施肥效应差异较大。与不施肥相比,水稻、小麦、油菜和棉花平衡施用氮、磷、钾肥分别平均增产2269、2200、1438和1617kg·hm-2,增产率分别为46.7%、109.8%、173.7%和68.6%;相对应的肥料对产量的贡献率分别为29.6%、48.6%、56.2%和38.0%,肥料农学利用率分别为7.2、7.7、4.0和3.0kg·kg-1。【结论】现代作物产量的提高和维持必须依赖肥料的施用,并且应该根据不同作物的施肥效应合理配置肥料资源,同时在保证农作物高产的前提下,提高肥料的利用效率。