为探讨不同微生物菌群对华北地区中度石油污染土壤的修复效果,在实验室模拟条件下分别进行优势外源石油降解菌群的筛选和优势菌群与植物联合修复试验.结果显示:4种外源石油降解菌群中,PDC-3菌群对中度石油污染土壤总石油烃(TPH,total petroleum hydrocarbons)去除率为84.07％,在各菌群中效果最优;该优势菌群与植物联合修复中度石油污染土壤比单独使用优势菌群修复可获得更好的效果,优势菌群与黑麦草联用及优势菌群与紫花苜蓿联用120 d TPH的去除率分别为91.58％和89.30％,修复后土壤中TPH含量均小于500 mg/kg;同时优势菌群与黑麦草联合修复在90 d即可去除89.32％的土壤TPH,相比选用紫花苜蓿可有效缩短修复周期;优势菌群对土壤TPH的去除起主要作用,其贡献率远高于土著微生物菌群或植物的贡献率;植物对土壤TPH去除的贡献率为4.09％～6.48％,且其作用主要发生在修复过程的中后期;优势菌群单独使用或与植物联合修复中度石油污染土壤120 d均可有效去除C10～C12及C22～C40石油烃组分,去除率为85.14％～100.00％;然而,C13～C21石油烃组分含量表现出阶段性的积累效应;除对土壤石油烃的去除作用外,使用优势菌群进行生物修复存在一定的调节土壤pH、增加土壤肥力,且有利于恢复修复后的土壤功能.
【Objectives】Zinc deficiency is very often happened in maize in saline fluvo- aquic soils in Hexi Oasis Area of Gansu Province,the high soil magnesium levels have been regarded as a major contributor to thisdeficiency. The inhibition effect of magnesium to zinc in saline fluvo- aquic soils in Hexi Oasis Area were discussed in this paper. 【Methods 】 A pot experiment was conducted with maize as materials. Exchangeable magnesium contents of 287. 3,349. 2,411. 6,487. 9 and 755. 2 mg / kg were obtained by irrigating different amount of Mg SO4 solution. The maize plants were harvested at 46 days,the biomass of above and under ground parts were dried and weighed,the Zn contents were measured. The second leaf under the interior leaf was used for the determination of active oxygen and some enzyme activities. 【Results 】1) More high and extremely high exchangeable Mg level in soil inhibits the growth of maize seedlings. When magnesia applied levels is 221 mg / kg,i. e. the exchangeable Mg content in soil is over 487. 9 mg / kg,the growth of maize is stressed,when the Mg2 +applied level is 515 mg / kg,i. e. the exchangeable Mg content in soil is over 755. 2 mg / kg,the plant height is markedly decreased by 14. 5%,showing symptoms of magnesia poison and zinc deficiency,such as withered leaf margins and partial white stripes on the leaves( P 0. 01). 2) With the increase of or exchangeable Mg levels,the dry weight in the of Mg2 +addition maize are reduced by 11. 9%- 38. 3% and 4. 6%- 11. 9% respectively. The reduction in stem weight is significantly higher than in roots. 3) Maize leaf chlorophyll contents are reduced by 9.4%-45. 9% with the increase of the Mg2 +addition. The Mg level of 515 mg / kg would lead to withered and yellow leaves. The blade superoxide dismutase( SOD),peroxidase( POD) and catalase( CAT) activities are increased at first and then reduced quickly,the peak value appears at the exchangeable Mg levels of 147,74 and 147 mg / kg respectively. When the dose reaches 515 mg / kg,the values are reduced by 49. 75%,48. 06% and 32. 21%respectively. The malondialdehyde( MDA) contents are increased consistently in the range of 20. 39%-183. 58%.4) The exchangeable Mg levels significantly inhibit the uptake of Zn. Compared with the CK,the zinc contents in above ground parts are reduced by 4. 05%- 57. 09%,the uptake reduced by 15. 41%- 73. 55%; the root zinc contents are reduced by 7. 55%-18. 99%,and the uptake reduced by 11. 62%- 37. 40%. The zinc content and absorption in stems / leaves are reduced more than in roots. High exchangeable Mg level would also lead to lower upward transfer of zinc. 5) Soil available zinc contents are significantly reduced with the increase of exchangeable Mg levels. When the Mg level reaches 515 mg / kg,i. e. the exchangeable Mg content in soil is over 755. 2 mg / kg,the available zinc content falls to 0. 47 mg / kg,which is below the critical value of zinc deficiency( DTPA- Zn 0.5 mg / kg).【Conclusions】Zinc deficiency of maize in saline fluvo- aquic soil in Hexi Oasis Area is closely related to soil magnesium content. The high levels of exchangeable Mg contents show significant restraining effects on the maize seedling growth and biomass,the leaf chlorophyll content and the activities of superoxide dismutase( SOD),peroxidase( POD) and catalase( CAT). Over high exchangeable Mg levels decrease the zinc absorption by maize seedlings,and the inhibition in stem / leaf is significantly higher than in root system,which inhibites the upward transfer of Zn from root to shoot. The available zinc content in soil will also be reduced,when the Mg level reaches515 mg / kg,the available zinc content is below the critical value of zinc deficiency.
叶绿素是作物进行光合作用合成有机物的主要色素,实时监测烤烟叶片叶绿素含量对跟踪烟株氮素营养状况和判别烟叶成熟度具有重要的指导作用.基于对烤烟叶片光谱特征的分析,以不同供氮水平下实测的烟叶高光谱数据及叶绿素相对含量(SPAD)为数据源,采用一阶导数(1st Der)、多元散射校正(MSC)、标准正态变量(SNV)和SG平滑(SG)对原始光谱数据进行预处理,先采用连续投影法(SPA)挑选出每个预处理条件下的特征波长,后将各特征波段下的光谱反射率作为模型的输入变量,利用反向传播神经网络(BPNN)、随机森林(RF)和支持向量机(SVM)3 种机器学习的方法分别构建烤烟叶片叶绿素含量估测模型.使用决定系数(R2)、均方根误差(RMSE)和平均绝对值误差(MAE)对每个机器学习模型的性能进行了评估和比较.结果表明:3 种机器学习方法训练出的模型相比较,RF模型的预测准确率最高;烤烟叶片原始光谱经MSC和SNV预处理后的光谱信息作为输入变量,经RF算法建模具有较高的精度和良好的预测能力,模型为MSC-SPA-RF(R2=0.96,RMSE=1.15,MAE=0.94)和SNV-SPA-RF(R2=0.96,RMSE=1.14,MAE=0.94).说明基于机器学习利用高光谱数据估算烤烟叶片叶绿素含量具有可行性,这为实时、精确地监控烤烟生长过程中叶片叶绿素含量变化状况以及合理科学的进行田间管理提供了一定的理论基础.
定量分析我国不同条件下紫云英配施化肥对水稻产量的影响,为紫云英配施化肥模式在稻田的推广应用提供科学依据.以单施化肥为对照,通过搜集整理已发表的田间试验数据,运用整合分析(Meta-analysis)的方法,明确紫云英配施化肥对水稻产量的综合效应,量化分析了水稻种植模式、化肥配施比例、紫云英翻压量、施肥量、土壤理化性状对紫云英配施化肥增产效应的影响.结果表明:与单施化肥相比,紫云英配施化肥显著提高了水稻产量,增产率为4.47％(95％CI,3.16％～5.77％),其中单季稻增产率为4.89％(95％CI,3.01％～6.76％),双季稻增产率为4.06％(95％CI,2.26％～5.87％).水稻增产率随化肥配施比例的增加呈逐渐上升趋势,当化肥配施比例≤0.4时,水稻减产4.58％(95％CI,-2.26％～-5.87％).水稻增产率随紫云英翻压量增加呈先上升后下降趋势,以紫云英翻压量为22500～37500 kg/hm2 时,增产率较高.稻田施氮量>180 kg/hm2、施磷量30～60 kg/hm2、施钾量60～120 kg/hm2 时,紫云英配施化肥的水稻增产率较高;土壤有机质含量<20 g/kg,土壤全氮含量<1.5 g/kg,土壤有效磷含量为10～20 mg/kg,土壤速效钾含量<50 mg/kg,土壤pH 6.5～7.5时,紫云英配施化肥的水稻增产率较高.综上所述,与单施化肥相比,紫云英配施化肥可显著提高水稻产量,且在土壤有机质、全氮含量较低,土壤pH偏中性条件下增产效果较好.紫云英配施化肥条件下,化肥减施20％～40％,紫云英翻压22500～37500 kg/hm2 仍能保证水稻增产.
紫色土分布区域降雨集中、土壤养分淋失严重,导致土壤肥力下降、根区养分供应不足、根系发育不良等问题,提升土壤养分的供应强度有利于优化根系空间分布格局和促进根系生长.将原料肥和有机物料混匀后,利用1400 kg/cm2 的强大压力将其压制成砖肥(BF),同时,设置原料肥和有机物料物理混合(CK)为对照.于关键生育期测定垄向截面不同土层深度和离烟株不同远近距离的格点位置的土壤电导率(EC)、不同直径的根系组成和根系生物量,采用Logistic模型、指数模型拟合根系空间分布关键参数和生物量累积关键参数,研究砖肥对烤烟根区电导率及根系生长的影响.结果表明:在烤烟根系主要分布区,即主根系半径12.5 cm处,深度2.5～12.5 cm的土壤剖面,BF处理的EC比CK高90.5～281.6 μS/cm;主根系半径17.5 cm处,深度2.5～17.5 cm的土壤剖面,BF的EC比CK高160.1～392.2 μS/cm.在主根系15～20 cm水平半径内,BF的根系重量比CK提高150％;分布在10～15 cm深度土层的根系重量提高了26.5％,并且土壤剖面10～20 cm之间的侧根伸展性更强、分布更广.移栽后75、90和105 d,BF的田间根系生物量分别比CK提高12.7、11.9和9.7 g/株,烟叶生物量分别比CK高24.5、13.6和17.1 g/株,根系和烟叶生物量最大累积速率分别比CK提高了43.5％和15.7％.对于淋失严重的土壤,施用砖肥可以提高养分供应强度、优化根系分布格局和促进烤烟生长发育.
为系统总结测土配方施肥对我国科学施肥工作的重要贡献,对测土配方施肥项目实施15年的发展进程进行了归纳,划分为启动扩大阶段(2005～2009年)、整建制推进阶段(2010～2014年)、绿色发展阶段(2015～2019年).利用国家测土配方施肥管理系统统计数据,研究了项目在构建我国土壤及作物肥效基础数据库、推动土壤肥料技术普及和提升农民科学施肥水平等方面取得的成效.结果表明,15年来测土配方施肥项目累计采集土壤样品2046.7万个、植株样品152.6万个,分析土壤样品1833.9万个、植株样品129.9万个,开展小区试验40.3万个、大田示范76.7万个,发布肥料配方31.1万个,培训农民3.26亿人次,化肥施用总量和单位面积化肥用量分别较峰值下降10.3％和10.1％,氮肥利用率提升11.7个百分点,2019年实现测土配方施肥推广面积1.38亿hm2.测土配方施肥项目成效显著,但在管理、技术等方面仍存在一些问题,特别是在测试化验、推荐施肥指标体系、技术物化、高效施肥技术推广等方面仍有改进和提升的空间,建议围绕农业绿色发展主线,进一步夯实测土配方施肥基础性工作,加强高效肥料品种和施肥技术的研发,强化技术推广,服务乡村振兴战略实施.
以内蒙古呼伦贝尔草甸草原作为研究对象,探讨土壤微生物化学计量特征在不同刈割频次处理下的变化规律,以期为草原资源的可持续利用提供理论依据.试验设有6个处理,对照区(CK)、1年1割(M1)、2年1割(M2)、3年1割(M3)、6年1割(M6)和12年1割(M12),每个刈割处理设置3个重复.2018年8月中旬在样地内随机设置3个样方,在样方内随机设置3个取样点,分别按0～10、10～20、20～30 cm土层进行均一采样,将土样按层次充分混合并带回实验室,采用氯仿熏蒸法对样品进行处理后,进行土壤微生物生物量碳(MBC)、氮(MBN)、磷(MBP)含量的测定.研究结果表明:刈割没有显著影响MBC、MBN、MBP含量及其化学计量比,表明刈割处理下微生物系统具有相对的稳定性.从6个处理的平均值整体来看,MBC、MBN、MBP含量以及微生物生物量C∶N、C∶P(MBC∶N、MBC∶P)随刈割间隔延长呈现先升高后下降的趋势,并在M2和M3处最高;本研究区各处理梯度MBC∶P平均值大于30,比值较高,微生物生物量N∶P(MBN∶P)低于全球平均水平(6.9或5.6).由于刈割一般在生长季后期进行,对草原生态系的影响比传统刈割要小得多,因此对MBC、MBN、MBP含量及其化学计量比的影响不明显,但适当的刈割不仅利于微生物的繁殖和根系的生长,而且对草原生态系统生产力以及植被群落产生积极影响,进而影响草地生态系统的结构和功能,因此应进行适宜的刈割.
Rare earth is physiologically active elements,which can affect the growth and development of plants,and plant roots can respond to exogenous plant growth regulators and regulate plant growth.Using tomato seedings as materials,the effects of lanthanum and cerium on the growth and root exudates of tomato seedlings were analyzed by hydroponic experiment. The results showed that the application concentration of rare earth elements at 0.05 mmol/kg promoted the increase of tomato plant height and leaf area,but inhibit them when the concentration reached 0.1 mmol/kg.The application of rare earth elements inhibited the growth of plant roots.The components and contents of tomato root exudates were identified and analyzed.There were 110 metabolites with significant difference between rare earth treatment and blank group,belonging to 10 secondary classifications and 38 tertiary classifications,among which the differences among Fatty acyls class ification,Carboxylic acids and derivatives class ification and Organoxygen compounds class ification were the most significant.However,the effect mechanism of various root exudates on tomato growth still needs to be further studied.
The wheat is a plant with fibrous root. Its root system consists of radicle（seed root）,nodal root（secondary root）and lateral root.Lateral root development of plants is not only controlled by genetic factors,but also affected by environmental factors. The study of investigating the development of lateral roots and nitrogen uptake in plants as influenced by local nitrate supply could provide technical support and theoretical basis for the selection and breeding of wheat varieties and increasing nitrogen absorption efficiency. Four wheat cultivars including H10,L14,Hengguan 35 and Shimai 15,were selected as the tested crops. Pot experiment was conducted with three nitrogen application rates of 0,94.5,473.5 kg/hm~2 to study their effects on biomass and aboveground nitrogen accumulation in different varieties of wheat. Nutrient solution split-root culture experiment was conducted with six treatments in two sides with nitrate supply levels of 0/0,0/2.5,0/50,2.5/2.5,2.5/50and 50/50 mmol/L. The results showed that:（1）the biomass and nitrogen accumulation in four varieties of wheat shoots were different under three nitrogen applications. H10 and Hengguan35 had higher biomass and nitrogen accumulation in shoots with the high nitrate treatment. L14 and Shimai 15 had higher biomass and nitrogen accumulation in shoots with the no nitrate treatment.（2）Under the addition of 50.0 mmol/L nitrate in both compartments,dry matter weight and nitrogen concentration of wheat shoots were higher in comparison to those without nitrate supply. More root biomass and lateral root density of Hengguan 35 were in the compartment with 2.50 mmol/L nitrate treatment than those without nitrate addition,while for the wheat cultivar L14,the 50.0 mmol/L nitrate increased root biomass and lateral root density in the nitrogen applied side. In the side with 2.50 mmol/L nitrate application,total lateral root length and average lateral root length of three wheat genotypes H10,Hengguan 35 and Simai 15 were higher than those of no nitrogen side. The stimulatory effect of 2.50 mmol/L nitrate on lateral root elongation was the highest in Shimai 15. Compared with the side without nitrate,total lateral root length and average lateral root length of four wheat genotypes were longer in the side with 50.0 mmol/L nitrate application.The highest increase of lateral root elongation under 50.0 mmol/L nitrate treatment was found in H10.（3）In the root split treatments,nitrogen concentration in wheat shoots was positively correlated with the increase rates of the average lateral roots length induced by nitrate supply,suggesting that localized nitrate supply could stimulate later root elongation of wheat,which would benefit plant nitrogen uptake. Local supply of nitrate obviously promoted the elongation of the lateral roots of wheat,and the induction effect was different between four wheat varieties. The greater inducing effect could benefit for nitrogen accumulation of wheat plants.
A pot experiment was conducted to investigate the effects of four amendments（biochar,biochar compound fertilizer,swine manure and lime） and their application rates on red soil pH,exchangeable acidity,soil nutrients,and maize growth.Ten treatments were included:chemical fertilizers only（CK）,biochar at levels of 1% and 3%（B1,B3）,biochar compound fertilizer at levels of 1% and 3%（BF1,BF3）,swine manure supplied 20%（M20） and 40%（M40） of total N,lime at levels of 0.02% and 0.04%（L0.02,L0.04）,M20+L0.02（M20L0.02）.The results showed that the BF1treatment significantly reduced soil pH by 0.19 units compared to the CK treatment,while the BF3,biochar,swine manure and lime treatments maintained soil pH;The B3,BF1,M40 and L0.04 treatments significantly decreased soil exchangeable acidity.The BF1 and BF3 treatments increased soil available nitrogen by 83 and 305 mg/kg,respectively,relative to CK;The M40 treatment significantly increased soil available phosphorus by 4.1 mg/kg,while the M20 treatment had no change. The B1,B3 and BF3 treatments increased soil available potassium by 46,138 and 171 mg/kg,respectively,compared to CK.Above-ground biomass was significantly reduced by 37% in the BF3 treatment compared to CK,and the highest value was observed in B3 treatment,which was significantly higher than that from BF3,M20,L0.02,L0.04 and M20L0.02treatments.Comparing with CK,the BF3 treatment significantly increased maize nitrogen uptake by 32%.The results showed that four improved materials could improve the acidity of red soil;Based on crop growth and nutrient balance,biochar can be used as a material to improve the acidity of red soil,which can appropriately reduce the input of potassium fertilizer.Carbon-based fertilizer can reduce the input of chemical nitrogen and potassium fertilizer,and swine manure can reduce the input of chemical phosphorus fertilizer.
In order to improve the applicability of multi-spectral image nitrogen nutrition diagnosis,six field trials with different nitrogen levels were set up with flue-cured tobacco as the research object,the multispectral image of flue-cured tobacco growth was regulary taken to test the nitrogen content of the plant.The correlation between vegetation index（NDVI,GNDVI,LCI,NDRE,OSAVI） and traditional nitrogen indicators,and the response between the optimal vegetation index and nitrogen application rate were analyzed.The results showed that the optimal monitoring period for flue-cured tobacco was around 50 days after transplanting,each vegetation index was most sensitive to the nitrogen content of single plant.The judgment standard of using vegetation index guiding the top dressing of field fertilization was N now =1911NDVI-1345.1,which provided new ideas and key technologies for high-quality top dressing of crops in a large area.
探究水肥一体化下磷肥种类和施用方式对棉花产量、磷素积累量、土壤磷素有效性和磷肥利用率的影响,以期为棉田优化磷肥施用方式提供理论依据和技术参考.田间试验于 2021 年在新疆昌吉州棉花主产区进行.试验设不施磷肥对照(CK)、基施重过磷酸钙(TSP)、基施磷酸一铵(MAP-B)、基施+滴施磷酸一铵(50%基施,25%+25%分别在蕾期和花铃前期)(MAP-D)、基施+滴施磷酸一铵(50%基施,25%+25%分别在蕾期和花铃前期)和聚谷氨酸(MAP-P)5 个不同施肥处理,测定指标包括土壤有效磷、植株生物量、植株磷积累量和籽棉产量,并计算磷肥利用率.在棉花盛花期和盛铃期,磷肥滴施显著提高 0～20 cm土层有效磷含量,0～5 cm土层尤为显著,MAP-P处理有效磷含量比CK处理分别提高 136.27%和 113.99%.TSP、MAP-B、MAP-D和MAP-P处理产量比CK处理分别提高 17.65%、16.25%、19.37%和 31.88%.棉花生育期内,磷肥滴施植株累积吸磷量高于基施,各处理植株累积吸磷量在盛铃期达最大,MAP-P处理植株累积吸磷量整体高于其余处理,在苗期、蕾期、盛花期和盛铃期比CK处理分别提高 50.92%、55.38%、81.33%和 84.69%.在等量施磷条件下,磷肥滴灌追施的磷肥利用率高于基施.MAP-P处理磷肥利用率、磷肥累积利用率、磷肥农学效率和磷肥偏生产力均高于其余处理,磷素表观平衡低于其余处理,磷肥利用率达 33.94%,比TSP、MAP-B和MAP-D处理分别提高20.23%、25.28%和 16.71%.水磷一体下,磷肥结合活化剂(聚谷氨酸)滴施显著提高土壤磷素有效性和棉花产量.MAP-P处理提高了棉花产量和磷肥利用率,减少了土壤磷素的盈余.
为探究叶面喷施硼肥对柑橘品质及土壤细菌群落的影响,通过田间小区试验,测定 3 个硼肥施用量水平 5 g/株(0.25%)、10 g/株(0.5%)、15 g/株(0.75%)处理的柑橘土壤、叶片硼含量及果实品质指标(果实横径、纵径、单果质量、可溶性固形物含量、可滴定酸含量、固酸比、维生素C含量)与土壤细菌群落.试验结果表明:适宜的硼肥施用量能较好地改善柑橘果实品质,高水平的硼肥处理反而降低柑橘品质.其中,0.25%硼肥施用量的处理效果最好.相较于CK(硼肥施用量为 0),该处理柑橘果实横径增加20.42%、纵径增加 6.21%、单果质量增加 24.62%;可溶性固形物含量增加 7.86%、可滴定酸含量降低 16.03%、维生素C含量增加 9.07%.硼肥喷施显著提升了土壤中抗病菌如Kaistobacter属、红游动菌属(Rhodoplanes)、芽孢杆菌属(Bacillus)、鞘氨醇单胞菌属(Sphingomonas)的相对丰度(P<0.05),其中 0.75%硼肥施用量土壤中Kaistobacter属从 0.42%提升至2.12%、红游动菌属从 0.37%提升至 1.36%、鞘氨醇单胞菌属从 0.18%提升至 0.59%.0.25%硼肥施用量将土壤中芽孢杆菌属从 0.23%提升至 1.88%,由此说明硼肥喷施可以影响土壤微生物.在提高柑橘品质及保障资源利用最大化的前提下,若柑橘种植生产中土壤有效硼含量缺乏,可以在柑橘的坐果期喷施1 次 0.25%硼酸溶液(即施用硼酸 5 g/株)的硼肥来满足柑橘树对硼营养的需求,进而提升柑橘品质.
为研究福建省农田常用商品肥中重金属的含量及其风险,采集福建省农田常用商品肥样品,用电感耦合等离子体质谱法(ICP-MS)和原子荧光光谱法(AFS)测定了 11 种重金属(Cd、Hg、As、Pb、Cr、Tl、Ni、Co、V、Cu和Zn)含量,对比分析不同商品肥中重金属含量分布并依据国家标准限值进行评价.结果表明:氮肥中Tl和Co未检出,而氮肥中其他9 种重金属以及其他商品肥中11 种重金属均有检出.不同商品肥中重金属含量的差异性较大,Tl和Cr表现为中等变异,其他重金属均表现为强变异.磷肥、有机肥和有机-无机复混肥中的各重金属含量相对较高.有机-无机复混肥中 40%样品的As含量超出《肥料中有毒有害物质的限量要求》(GB 38400-2019)规定的限值,而有机-无机复混肥中其他重金属以及其他商品肥中各重金属含量均在限值之内.不同种类商品肥受生产原料的影响使重金属含量差异较大,应从源头上进行严格控制.所研究的商品肥中重金属含量整体上处于安全水平,但商品肥中重金属可能对农田系统产生的风险不可忽视.考虑到重金属的蓄积性,应从重金属含量、施肥方式及施肥时长等方面重点关注Cd、Hg、As和Pb的潜在污染.
为明确长三角冬油菜种植区专用缓释肥用量(N-P2O5-K2O:25-7-8)对油菜生长和产量形成的影响,以提升油菜增产潜力和资源利用率,2020-2021 年在江苏省苏州市布置田间试验.试验设置 5 个处理,分别为不施肥(CK)和施用缓释肥处理(施用量分别为 750、900、1050 和 1200 kg/hm2,分别以F750、F900、F1050 和F1200 表示),并测定油菜产量和产量构成、干物质积累量和氮吸收量变化特征与肥料利用效率等指标.结果表明:与CK相比,施用缓释肥油菜产量显著增加了 1.81～2.67 倍,且在施用量 900 kg/hm2 时产量和肥料贡献率最高(P<0.05),其他施肥水平间表现相当.油菜产量与分枝数、角果数及株高显著相关.F900 处理油菜角果数显著高于F1050 和F1200 处理(P<0.05).各处理油菜角粒数和千粒重处理间无显著差异.油菜株高随缓释肥用量的增加逐渐增加.缓释肥用量为 750 kg/hm2 时显著抑制油菜苗期地上部干物质积累量和氮素吸收量,施肥量增加至1200 kg/hm2 时苗期地上部生物量显著提高了 38.8%(P<0.05),施肥量为 900 和 1050 kg/hm2 则介于中间.油菜花期时则表现为 900 kg/hm2 水平下作物生长速率与氮素吸收速率显著优于其他处理,缓释肥 750 和 1200 kg/hm2 用量时作物生长速率分别显著降低了 17.4%和 14.9%(P<0.05),作物氮素吸收速率与生长速率表现趋势基本一致.缓释肥用量的增加显著提高了油菜苗期肥料贡献率,但是显著降低了肥料农学利用效率.油菜终花期后土壤中无机氮含量随着缓释肥用量的增加呈先增后降的趋势.综上所述,长三角农区油菜生产缓释肥推荐用量为 900 kg/hm2,其中氮、磷和钾养分投入量分别为N 225 kg/hm2、P2O563 kg/hm2 和K2O 72 kg/hm2,可进一步优化油菜不同阶段干物质积累与氮素吸收,提高油菜分枝数和角果数,从而提高油菜产量和肥料农学利用效率.
鉴于日光温室和农田两种土地利用施肥和农艺措施的差异,研究由农田向日光温室转变后深层土壤磷素累积及分布,为评价磷素有效性及淋失状况,指导日光温室磷肥合理施用,降低磷素损失提供理论参考.对黄土高原东北部日光温室及农田磷肥投入和携出状况调查,同时,采集 0～400 cm土层土壤剖面样品,测定土壤Olsen-P和CaCl2-P含量,比较两种土地利用方式下养分平衡及深层土壤剖面磷素的累积及分布状况.结果显示,日光温室磷肥年均投入量为 897 kg/hm2,显著高于农田,磷盈余量平均为 679 kg/hm2,为农田的 10.9 倍.日光温室 0～20 cm土层土壤Olsen-P含量高达 400.5 mg/kg,为农田对应土层的 44 倍;0～40、40～100、100～200、200～300、300～400 和 0～400 cm土层土壤剖面Olsen-P累积量分别为 1637、443、277、378、258 和 2993 kg/hm2,显著高于农田对应土层累积量(41、54、122、174、163 和 554 kg/hm2);40 cm以下土层Olsen-P累积量占整个 0～400 cm土层土壤剖面累积量的 45.3%,磷素出现了明显的淋溶损失现象.土壤剖面各土层CaCl2-P含量均随Olsen-P含量的增加而增加,二者表现为显著的正相关关系.结果表明,研究区由农田向日光温室转变显著增加了土壤磷素的累积及向深层土壤的淋溶损失.因此,日光温室降低磷肥投入,改善管理措施十分必要.
为了解云南省菠萝蜜主要种植园土壤和叶片养分状况,以期为菠萝蜜园合理施肥提供依据.调查分析了云南省具有代表性的 15 个种植园不同土层(0～20、20～40、40～60 cm)的土壤养分状况和叶片养分含量,结合土壤养分分级标准,分析其相关性.结果表明:(1)土壤养分含量在 0～20 cm土层含量最为丰富;不同土层间除土壤pH、有效硼之外,有机质及其他养分元素均有含量变幅范围、变异系数较大的表现.(2)86.67%土壤pH值小于 6.5,土壤呈酸性,有机质、全氮、全钾、碱解氮、速效钾及各种中、微量元素含量中上水平,磷素含量各种植园表现不一,差异明显.(3)土壤有机质与土壤全氮呈极显著正相关关系;土壤全磷含量与土壤速效钾、有效锌、交换性钙呈极显著正相关关系,与有效磷、有效锰呈显著正相关关系;土壤pH与土壤交换性镁呈显著正相关关系,与叶片氮、锰、锌、铜呈显著负相关关系;叶片钙与土壤交换性钙呈显著正相关关系.因此,建议云南省菠萝蜜种植园施用石灰或者土壤调理剂提高土壤pH,增施有机肥、磷肥、硼肥,适当控制氮肥、钾肥、钙镁中量元素肥及铁锰铜锌微量元素肥的施入量,以达到平衡施肥的目的.
利用低温脱水工艺对氨基酸发酵尾液进行干燥生产固体氨基酸水溶肥料增效物质.将其与普通水溶肥混合,制备氨基酸水溶肥料.在田间试验条件下研究氨基酸水溶肥料对番茄生长的影响.设置等量NPK普通水溶肥料(CF)、等量NPK氨基酸水溶肥料(AF)、减量 20%NPK普通水溶肥料(4/5CF)、减量 20%NPK氨基酸水溶肥料(4/5AF)4 个处理,研究氨基酸水溶肥对设施番茄产量、品质及经济效益的影响.结果表明,与CF处理相比,AF、4/5CF、4/5AF处理分别增产 11.23%、-3.59%、2.62%;通过平均隶属函数值得出氨基酸水溶肥可以显著提高番茄果实品质,以可溶性糖和维生素C含量的提升最为明显,较CF处理平均分别提高 29.4%和 8.25%,AF处理和 4/5AF处理较CF处理经济效益每公顷分别增加 52533.0 和 12049.5 元.氨基酸水溶肥NPK减量 20%仍可确保增产,且其果实品质优于普通水溶肥.
为了研究解钾菌肥是否具有抗光亏缺的作用,模拟自然条件,在培养箱的弱光照(66%)条件下,用解钾菌参与活化的钾长石肥料与其他肥料在相同养分水平下进行玉米盆栽试验.结果表明,在弱光条件下,两种解钾菌处理都能够促进玉米生长.其中,以T1(菌Q22)的效果最明显,且差异显著.显示了微生物肥料具有抗光亏缺的独特优势,值得深入研究.这不仅可为高产栽培提供新的技术支撑,还可为微生物肥料开拓广阔的应用场景.
合理的养分供应对基质栽培蔬菜的优质高效生产尤为重要.通过研究氮、磷、钾不同施肥量及配施比例对戈壁滩日光温室基质栽培辣椒产量和品质的影响,明确获得基质栽培高产优质辣椒的适宜氮、磷、钾用量及养分配比.采用三因素五水平二次通用旋转组合设计,以产量和品质综合得分为目标函数,以氮、磷、钾施用量3个因素为因变量,构建数学模型进行试验研究.研究结果表明,氮、磷、钾肥对基质栽培辣椒产量及品质均有显著影响,对辣椒产量的影响排序为钾肥>氮肥>磷肥;对辣椒品质综合得分的影响排序为氮肥>磷肥>钾肥;当氮、磷、钾肥用量分别达376.22、164.41、595.31 kg/hm2 时,边际产量效应值降至0,当氮、磷、钾肥用量分别达245.13、115.65、367.13 kg/hm2 时,边际品质综合得分效应值降至0.氮磷、氮钾、磷钾互作对产量具有较强的促进作用,对氮而言,钾的交互效应大于磷;对磷而言,钾的交互效应大于氮;对钾而言,氮的交互效应大于磷.利用模型进行计算机模拟,本试验条件下辣椒产量超过53000 kg/hm2 时的氮肥施用量为233.36～307.76 kg/hm2,磷肥施用量为112.71～149.74 kg/hm2,钾肥施用量为360.01～475.88 kg/hm2.辣椒品质综合评分在84分以上的氮肥施用量为193.12～267.17 kg/hm2,磷肥施用量为90.74～153.19 kg/hm2,钾肥施用量为289.67～437.25 kg/hm2.综合来看,获得高产优质的戈壁日光温室秋冬茬基质栽培辣椒的氮肥施用量为233.36～267.17 kg/hm2,磷肥施用量为112.71～149.74 kg/hm2,钾肥施用量为360.01～437.25 kg/hm2,适宜的N、P2O5、K2O施用比例约为1∶0.48∶1.54.
