浅埋滴灌水氮运筹对春玉米产量及水分利用效率的影响

采用二因素二次饱和D-最优设计，于2016-2017年在辽西半干旱区移动遮雨棚内进行了水氮精量控制试验，设灌溉量和施氮量2个因素，灌溉量分别设145.4、271.7、348.2、436.2 mm 4个水平，施氮量分别设0、84.6、136.1、195.0 kg·hm^-2 4个水平，共6个处理。试验分析了水氮交互作用对春玉米产量和水分利用效率的影响，建立了产量回归模型。研究结果表明：浅埋滴灌条件下，灌溉量在145.4~350.5 mm时，春玉米产量随灌溉量的增加而增高至11 005.60 kg·hm^-2；灌溉量在350.5~436.2 mm时，产量随灌溉量的增加而降低至10 730.09 kg·hm^-2；施氮量在0~146.9 kg·hm^-2时，产量随施氮量的增加而增高至10 983.19 kg·hm^-2，施氮量在146.9~195.0 kg·hm^-2时，产量随施氮量的增加而降低至10 862.39 kg·hm^-2。灌溉量因素的影响大于施氮量，水氮之间有明显的正向交互效应，当灌溉量为373.1 mm，施氮量为165.6 kg·hm^-2时产量最高。作物耗水量在拔节-抽雄期和灌浆-收获期较大，分别为115.64、127.50 mm；水分利用效率随灌溉量的增加呈逐渐降低趋势，降低幅度达到52.21%，随着施氮量的增加则呈先升高后降低趋势，增幅为14.73%~20.08%；其中处理6（灌溉量348.2 mm，施氮量195.0 kg·hm^-2)最利于水分利用效率的提高。综合产量和水分利用效率两方面的因素，初步建立了春玉米浅埋滴灌水氮施用优化模式，参数组合为灌溉量348.2 mm、施氮量165.6 kg·hm^-2。     

滴灌模式和水分调控对夏玉米干物质和氮素积累与分配及水分利用的影响

采用裂区试验设计探究了地下滴灌和地表滴灌(drip underground, DU; drip surface, DS)模式下土壤水分调控(分别为田间持水量的40%～50%、60%～70%和80%～90%,记为W40、W60和W80)对夏玉米干物质和氮素积累与分配及水分利用效率的影响。结果表明,DU处理的吐丝后氮素积累量及水分利用效率分别较DS显著提高了6.18%和4.85%～8.61%。夏玉米的干物质、氮素指标及产量对滴灌模式的响应依赖于土壤水分调控水平,在W40和W60处理条件下,DU处理显著增加夏玉米的净光合速率,提高了吐丝后干物质和氮素的积累量及向籽粒的转运,最终DU处理的干物质积累量、籽粒氮素积累量、产量及氮肥偏生产力分别提高了3.29%～19.94%、?1.10%～20.65%、3.29%～19.94%和3.31%～23.64%。而在W80处理条件下, DS处理的干物质积累量、吐丝后氮素积累量、产量及蒸散量比DU处理分别提高了6.80%～12.24%、5.93%、8.39%～14.91%和9.73%～14.57%。综上所述,在限水灌溉条件下,地下滴灌能够增加吐丝后干物质积累量、氮素积累量及其对籽粒氮素的贡献率,最终增加产量。在充分供水条件下,地表滴灌更有利于干物质及氮素的积累,但由于消耗过多的水分,因此水分利用效率未显著增加。     

Intercropping fenugreek (Trigonella foenum‐graecum L.) and barley (Hordeum vulgare L.) with and without biochar: Tests along a competition gradient

Integrating soil amendment biochar to legume‐based intercropping systems may amplify the intercropping benefits and lead to more sustainable production due to its positive effects on the soil physicochemical and biological environment. Fenugreek (Trigonella foenum‐graecum) is a legume used in an intercropping system in several countries in Southern Europe, the Middle East, and Asia. A barley cultivar and an Iranian fenugreek ecotype were studied in two replacement series experiments to find the best combination of the two species as well as the effect of adding biochar to the soil. Fenugreek and barley were grown in 4‐L pots in five density combinations (20:0, 15:5, 10:10, 5:15, 0:20) with and without application of biochar in sandy loam soil. The biomass, nitrogen (N) and carbon (C) amount of the two crops were measured fifty days after sowing, and the Relative Yield Total (RYT) was estimated. Our results showed that biochar application resulted in a higher total biomass, N and C amount in all combinations of fenugreek and barley. Total biomass was increased by biochar 19.2% when fenugreek was grown alone and 8.1 and 12.9% in series with 25 and 50% barley when biochar was added, respectively. Biochar increased dry matter, N and C accumulation in both crop species in the mixtures. An exception was the C amount of barley which was not influenced by biochar in intercropping. RYT values were largest for biomass, C and N amount in mixtures with 15 fenugreek plants per pot and 5 barley plants per pot corresponding to approximately 400 fenugreek plants per m mixed with 130 barley plants per m². Biochar application increased RYT of the total dry weight by 2.7 and 5.5% in mixtures of 25 and 50% barley plants, RYT of the total nitrogen by 0.8% in mixtures with 25% barley plants, and RYT of the total carbon by 2.7 and 6.6% in mixtures with 25 and 50% barley plants. The RYT values declined with increasing number of barley plants as a result of a less competitive ability of fenugreek when growing in high barley densities. The yield was highest with intercropping but monoculture of barley also resulted in high yields. The total highest yield was found when approximately 130 fenugreek plants per m² were mixed with 400 barley plants per m². Mixtures with 75% fenugreek and 25% barley obtained RYT values larger than 1 for biomass, carbon and nitrogen percentages.     

Diversity in daytime and night‐time transpiration dynamics in barley indicates adaptation to drought regimes across the Middle‐East

A challenge to breeding drought‐tolerant barley in the Middle‐East is that precipitation and evaporative demand patterns dictate opposite water use strategies (conservative vs. risk‐taking). To characterize these strategies, we examined high‐resolution, whole‐plant transpiration rate (TR) responses to increasing vapour pressure deficit (VPD) and nocturnal TR (TR_N) dynamics among 25 local barley genotypes, using a novel phenotyping system. These traits were specifically selected because they exist under modalities enabling the expression of both strategies. The genotypes were selected from locations spread across a large aridity gradient represented by temperature and precipitation data spanning 30 years. Here, we uncovered a substantial diversity in TR responses to VPD where slopes of the linear responses correlated negatively with local maximal temperatures, pointing to opposite drought tolerance strategies. Low canopy conductance (low slopes) was associated with higher aridity, likely to enable water‐saving, while higher conductance was associated with wetter areas, likely to enable a more aggressive water use to maximize physiological activity. TR_N was highly diverse and represented up to 15% of maximal daytime TR, pointing to the possibility of increasing water‐saving by reducing TR_N. Furthermore, we detected pre‐dawn variation in TR_N that negatively correlated with local precipitation, indicating that a tighter circadian control is associated with adaptation to drought, consistently with a circadian resonance mechanism. These findings indicate that canopy conductance and TR_N are potentially beneficial to design drought‐tolerant barley germplasm adapted to different drought regimes taking place in the Middle‐East.     

不同控释氮肥运筹对粳稻养分吸收与氮素利用的影响

以绥粳18为供试材料,通过盆栽试验,在一次性施入控释氮肥免追肥条件下,设置不同施肥量(高、中、低、无)和施肥深度(5 cm、10 cm),探讨不同氮肥施用方式对粳稻养分吸收和氮素利用的影响。结果表明,在不同氮肥运筹条件下,粳稻各生育期氮、磷、钾的吸收、转运均存在明显的协同效应,施肥深度5 cm组,随着氮肥施用量的增加,粳稻的氮吸收总量增加,同时可促进磷的吸收,但影响幅度较小。钾变化与氮、磷变化有所不同。施肥深度10cm组,施高量氮肥抑制了粳稻对磷的吸收、减少了对氮的吸收,但有利于提高氮素利用率,对钾的吸收无显著影响。施用树脂包膜控释肥,纯氮用量为153 kg/hm^2、施肥深度5 cm、一次性施肥免追肥可获得最优水稻氮素利用效率并显著提高磷钾肥利用效率。     

泰州市稻田综合种养产业发展分析及建议

系统阐述了泰州市稻田综合种养产业的发展现状,包括分布区域、经营主体、种养模式等,统计了不同种养模式的应用面积、产量及收益,对稻田综合种养及常规稻麦种植两种模式下的经济效益进行了对比。结果表明,稻田综合种养模式能显著提高土地利用率,促进当地农业增效和农民增收。通过对稻田综合种养模式推广应用过程中的比较优势以及存在问题进行系统分析,提出了针对性的解决措施和建议。     

覆膜方式对雨养饲用玉米生长、产量及水分利用效率的影响

为促进冀西北坝上高寒半干旱区旱地饲用玉米稳产、高产和提高水分利用效率，于2016—2017年在农业部张北农业资源与生态环境重点野外观测试验站，进行了露地平作(ck)，双垄沟覆膜、微垄覆膜、土下覆膜处理对饲用玉米叶面积指数、干物质积累、土壤水分、产量和水分利用效率影响的试验研究。结果表明，在丰水年，双垄沟覆膜处理效果最好，与露地相比叶面积指数、干物质积累量、土壤蓄水量分别提高36.45%、70.24%、13.25%，产量和水分利用效率提高了67.24%和87.66%；在欠水年，土下覆膜处理效果最佳，较露地增产71.31%，水分利用效率提高81.69%。双垄沟覆膜是寒旱区提高饲用玉米产量和高效利用降水的有效技术，土下覆膜则更适用于土壤贮水丰富农田的高水效生产。     

油草混播种类对油菜生产和草地生产性能的影响

为筛选与门源油菜混播效益最高的牧草种类,解决油菜连作障碍问题,提高青藏高原高海拔区土地的生产能力,本研究采用油菜混播箭筈豌豆、青稞和燕麦的方式,分时段取样,探究了油菜混播不同牧草对在不同时段牧草自身生产能力的影响,并通过土地当量比判断各混播组合的优劣。研究表明油菜-燕麦混播处理在7月6日时表现干重最高,单位面积达174.48 g；在7月21日表现为鲜重和鲜干比最高,在8月15日时表现为株高显著高于单作油菜(p＜0.05),较单作油菜高97.02%；鲜重最高,达2817.00 g。在9月11日,油菜-青稞和油菜-燕麦混播处理的株高显著高于单作油菜(p＜0.05),分别较单作油菜高64.33%和99.68%,以油菜-青稞混播处理的干重最高,达589.00 g,较单作油菜处理高147.51%。油菜-箭筈豌豆混播和油菜-燕麦混播有产量优势,油菜-燕麦混播的土地当量比最高,为1.11,土地利用效果最好。     

华南地区主要蔬菜磷钾肥料利用率研究现状

总结了近年来在华南地区主要蔬菜生产区进行的田间试验结果,分析了施磷钾肥对叶菜、瓜类、豆类蔬菜产量和养分吸收的影响,以及目前条件下华南地区蔬菜磷钾肥的偏生产力、农学效率、肥料表观利用率、生理利用率、肥料贡献率和地力贡献率。结果表明,叶菜、瓜类和豆类蔬菜施用磷钾肥均能促进蔬菜产量的增加和磷钾养分的吸收。叶菜、瓜类、豆类蔬菜磷肥偏生产力分别为781.9 kg/kg、257.6 kg/kg、211.9 kg/kg,农学效率为30.5 kg/kg、64.1 kg/kg、23.1 kg/kg,表观利用率为17.2%、9.7%、6.1%,生理利用率为222.3 kg/kg、370.6 kg/kg、292.7kg/kg,肥料贡献率为16.4 %、19.4%、12.9%,地力贡献率为83.6 %、80.4%、87.1%。叶菜、瓜类、豆类蔬菜钾肥偏生产力分别为298.8 kg/kg、164.3 kg/kg、165.8 kg/kg,农学效率为29.5 kg/kg、39.5 kg/kg、25.8 kg/kg,表观利用率为24.8%、24.3%、13.0%,生理利用率为152.3 kg/kg、218.6 kg/kg、229.1kg/kg,肥料贡献率为13.8 %、21.6%、17.4%,地力贡献率为86.2 %、78.3%、82.6%。分析肥料利用率分布频率可以看出,磷肥表观利用率＜20%的试验样本和钾肥表观利用率＜30%的试验样本均占总样本的80%以上,表明目前试验条件下各类蔬菜的磷钾肥利用率较低,生产上需同时解决蔬菜产量及肥料利用效率提高的问题。     

氮肥利用率的研究进展

为了提高作物的氮肥利用率，减少资源浪费、降低环境污染和提高作物产量提供科学依据。文章回顾了国内外近年来氮肥利用率的研究成果，从氮肥利用率的研究方法及影响因素等方面分析了氮肥利用率的研究历史、现状和存在问题。归纳得出中国氮肥利用率较低，施肥缺乏科学性，具体表现为氮肥施用量过大、氮肥挥发及硝化反硝化损失严重、施肥时期及施用量与作物氮素吸收规律不协调、肥料品种较单一等。建议结合测土配方施肥、实时监控管理等技术，合理地确定氮肥种类、用量、施用方式及时期，加强新型肥料及肥料增效剂等新技术的研发和推广，并注重作物氮高效品种资源的挖掘和应用，进而从土壤、肥料、品种、管理方式等多方面提高氮肥利用率。