Effects of Fermented Nori (<i>Pyropia yezoensis</i>) Seaweed Liquid Fertilizers on Growth Characteristics, Nutrient Uptake, and Iodine Content of Komatsuna (<i>Brassica rapa</i>L.) Cultivated in Soil

We investigated the effects of fermented nori (Pyropia yezoensis) liquid fertilizers on plant growth, soil plant analysis development (SPAD) values, and nutrient uptake of komatsuna (Brassica rapa L. var. wakana komatsuna) plants. The four types of fermented nori seaweed liquid fertilizers (SLFs) evaluated in this study were prepared by anaerobic fermentation of unwashed nori (SLF1), aerobic fermentation of unwashed nori (SLF2), anaerobic fermentation of washed nori (SLF3), and aerobic fermentation of washed nori (SLF4). In Experiment 1, the highest plant growth, SPAD, and nutrient uptake values were obtained from treatment with SLF2 and SLF4. There were no significant differences between the effects of basal and foliar application of SLFs, except for iodine (I) content;plants treated with SLF1 had the highest I content. In Experiment 2, plant growth and nutrient uptake decreased with higher concentrations of SLFs. Plants treated with 25% SLF2 + 75% chemical fertilizer (CF) or 25% SLF4 + 75% CF exhibited significantly higher plant growth and nutrient uptake. The highest I content resulted from treatment with 75% SLF1 + 25% CF or 100% SLF1. Taken together, our results showed that 25% SLF + 75% CF produced the best plant growth characteristics, nutrient uptake, and I content relative to the controls. Therefore, basal application of these liquid organic fertilizers can be used to increase productivity, nutrient uptake, and I content and to reduce nitrate-nitrogen content in komatsuna production.

Analysis and comparison of nutrient contents in different animal manures from Beijing suburbs

Manure samples were collected by floor scrapings in animal stables from Beijing suburbs. Total nitrogen (TN), total phosphorus (TP), and total potassium (TK) were analyzed by conventional wet chemical methods. All manures showed a high variability in nutrient contents. Nutrients contents in different animal manures were significantly different. TN and TK contents in layer manures were higher than swine and dairy manures

Yield of Wheat (<i>Triticum aestivum</i>) and Nutrient Uptake in Grain and Straw as Influenced by Some Macro (S &Mg) and Micro (B &Zn) Nutrients

A wheat variety BARI Gom 26 was cultivated with an objective of evaluating the effects of macro/secondary nutrients as S and Mg, and micro nutrients as B and Zn on yield, yield contributing traits and nutrient uptake status by the crop. The field experiment was con-ducted in the “North Eastern Barind Tract Soils” at Kushadaha, Nawabganj, Dinajpur, Bangladesh from November, 2014 to March, 2015. The surface soil was clay in texture, having pH 5.61, organic matter 1.58%, total N 0.10%, available P 7.03 ppm, exchangeable K 0.11 meq/100g, available S 2.57 ppm, exchangeable Mg 0.55 meq/100g, available Zn 1.30 ppm, available B 0.08 ppm. The experiment was designed with five treatments laid out in a randomized complete block design (RCBD) with three replications. The treatments were T1: NPK (control), T2: NPK + S, T3: NPK + S + Mg, T4: NPK + S + Mg + Zn and T5: NPK + S + Mg + Zn + B. All plots of wheat received 100 kg N/ha, 30 kg P/ha and 70 kg K/ha as basal dose. The secondary and micro nutrients doses were 15 kg S/ha, 6 kg Mg/ha, 2.5 kg Zn/ha and 1.5 kg B/ha. Results revealed that the plant height, tillers/hill, 1000-grain weight, yield of grain and straw, uptake of some specific nutrients in grain and straw were signifi-cantly influenced by all the treatments, though these treatments did not show any identical effect on spike length, content of P and Mg in wheat. Significantly highest amount of 1000-grain weight, yield of grain and straw weight of wheat were obtained in applying T2 treatment that employed the addition of S with recommended dose of NPK. Significant positive effects were also observed for the rest parameters in receiving the treatments composed of secondary and micronutrients (T3, T4, and T5). The highest concentration of nutrient uptake N, P, K and S in grain and straw of wheat were also obtained due to the application of T2 treatment. In the case of Mg, the maximum uptake was recorded in T4 where Mg was added as a component of this treatment. In contrast, the highest content of Zn and B were extracted in receiving the treatment T5 both for grain and straw. However, results suggested that T2 treatment comprising recommended dose of NPK with S might be economic and suitable as for better production of 1000-grain weight, yield of grain and straw, uptake of N, P, K and S in grain and straw of wheat cultivated in the North Eastern Barind Tract Soils of Bangladesh under winter condition. The treatment T5 would also be recommended in the context of addition of micronutrients.

Responses of Contrasting Rice (Oryza sativa L.) Genotypes to Salt Stress as Affected by Nutrient Concentrations

The study was conducted to investigate the effects of applying different concentrations of the macronutrients K＋,Ca2＋,and Mg2＋ on the responses of contrasting rice（Oryza sativa L.） genotypes under salt stress.A solution culture experiment was conducted in a phytotron at the International Rice Research Institute（IRRI）,under controlled temperature and humidity and natural sunlight.When subjected to salt stress of 100 mmol L-1 using NaCl,the salt tolerant genotypes FL478 and IR651,accumulated less Na＋ and maintained lower ratios of Na＋/K＋,Na＋/Ca2＋,and Na＋/Mg2＋ than the sensitive genotypes IR29 and Azucena.These tolerant genotypes also had higher concentrations of K＋ in their shoots and greater root and shoot biomass and green leaf area.Tolerant genotypes also maintained much lower concentration of Na＋ and lower and more favorable ratios of Na＋/K＋,Na＋/Ca2＋,and Na＋/Mg2＋ in their active and developing tissues.Salt tolerance and shoot and root growth of both tolerant and sensitive genotypes were enhanced considerably when higher concentrations of Ca2＋ and Mg2＋ were applied in culture solution.The concentration of Na＋ and the ratios of Na＋/K＋,Na＋/Ca2＋,and Na＋/Mg2＋ in shoots also declined significantly.The beneficial effects of higher calcium were greater than that of magnesium and application of higher concentration of K＋ seems to have minor effects.Responses to salinity in rice can therefore be considerably enhanced through proper nutrient management,by increasing the concentrations of nutrient elements that have favorable effects such as Ca2＋ and Mg2＋.Calcium is particularly more effective than both magnesium and potassium,and can be applied at relatively larger quantities in salt affected soils.

Growth Medium and Soil Amendment Influence on Seedling Growth Responses of African Star Apple (Chrysophyllum albidum)

African Star Apple (Chrysophyllum albidum) classified as a forest food treewith economic potentials requires domestication attention for improvedproductivity. A study conducted in Abeokuta, Nigeria in 2017 using oneyear old C. albidum seedlings determined the plant’s growth responseswhen cultivated using different growth medium and soil amendmentmethods. The 3 x 9 factorial experiment was arranged in a CompletelyRandomized Design (CRD) at three replications. Three textural soil types(sandy, loamy and clayey soils) were evaluated using nine soil amendmentmethods (5, 10, 15t/ha poultry manure (PM) and 150, 250 and 500kg/haNPK, and integrated amendment methods using 5t/ha PM+150kg/ha NPKand 10t/ha PM+150kg/ha NPK), and the un-amended plot as control. Theresults showed that plants in loamy and clayey soils had more leaves comparedto those in sandy soil only at 74WAS. C. albidum had most numerousleaves with 150 kg/ha, taller plant and wider canopy with 250 kg/ha, andthicker girth with all NPK rates compared to control, manure rates and integratedfertilizers. The plants with loamy soil had highest CPC, Ash C, FC,starch and sugar. Plants with inorganic fertilizers and integrated fertilizershad higher FW and DW compared to manure rates. The 5 t/ha manure rateand the 250 kg/ha NPK produced plants with high sugar content and werelowest in starch content compared to other applied rates. In conclusion, C.albidum from juvenile to vegetative stage with proper management can begrown on the different soil types while the 150 kg/ha NPK fertilizer rateappeared as optimum for the plant growth.

农作物秸秆饲料营养价值及经济效益分析研究进展

农作物秸秆作为一种常见的饲料来源,在畜禽养殖中起重要作用。不同农作物秸秆的营养价值和经济效益受地域、气候、农业活动等多种因素影响,不同农作物秸秆的营养含量存在差异,水稻秸秆富含碳水化合物和纤维素,适合作为猪饲料;玉米秸秆中的植物纤维含量较高,适合用于牛羊饲料。合理利用不同种类的农作物秸秆可以提高畜禽的生长速度,降低饲养成本,从而带来经济效益。本文主要探究不同农作物秸秆饲料的产量及营养价值情况,并对畜禽饲养成本及经济效益进行探究,为不同农作物秸秆饲料的利用提供一定参考。

杉木林下七叶一枝花各器官的主要养分含量及其分配特征

[目的]了解和掌握七叶一枝花Paris polyphylla Smith var.chinensis花期各器官的养分含量及其分配特征,为其林下栽培和养分管理提供科学依据。[方法]以杉木Cunninghamia lanceolata林下人工种植的七叶一枝花为研究对象,于花期进行采样,统计分析各器官的N、P、K、Ca、Mg等主要养分含量、分配特征及各养分含量间的相关性。[结果]七叶一枝花各器官中的N含量从高到低依次为叶、花、须根、块茎、茎,叶中N含量最高达29.61 g/kg;P含量从大到小依次为花、叶、须根、块茎、茎,花中P含量最高达4.75 g/kg;钾含量从大到小依次为叶、花、茎、须根、块茎,叶中K含量最高达25.23 g/kg;Ca含量从大到小依次为块茎、须根、茎、叶、花,块茎中Ca含量最高达4.75 g/kg;Mg含量从大到小依次为叶、花、须根、块茎、茎,叶中Mg含量最高达3.11 g/kg;七叶一枝花各器官养分含量从大到小依次为N、K、Ca、Mg、P;各器官养分含量间除了块茎中的N与Mg呈显著负相关外(P<0.05),其余指标间的相关性均未达显著水平。[结论]七叶一枝花花期各器官的养分含量主要集中在叶和花中,N和P可能是限制七叶一枝花生长的主要营养元素。

深圳市典型建筑渣土填海区绿地土壤理化特征研究

由于深圳市填海区土壤没有经过原位自然成土及生物演替过程,加上受经济发展和城市化进程的影响,导致绿地土壤质量下降,理化性质发生改变,因此开展填海区绿地土壤研究对于改善该区域生态环境具有重要意义。为明确该区域生态建设的主要障碍因子,于2018年在深圳前海自贸区采集20个土壤剖面(75个样品),采用物理和化学分析方法,测定了其土壤水分、盐分和养分的分布特征。结果表明:土壤含水量、盐分参数和养分含量在土层间的差异均未达到显著水平(P>0.05),在垂直剖面上的分布较为稳定。土壤容重随着土层深度的增加先上升后下降,以30~60cm土层最高,而含水量的变化趋势相反,其随着土层深度的增加先降低后升高,以120~150cm最高,呈底聚型分布。土壤电导率和Na^(+)随着土层深度的增加先上升后下降,在60~90cm达到峰值,分别为其余土层的1.32~2.42倍、1.13~2.75倍,全盐量、Cl^(-)和SO_(4)^(2-)则呈现“降-升-降”的趋势,且电导率、全盐量与Na^(+)、Cl^(-)和SO_(4)^(2-)间均存在极显著相关关系(P<0.01。)此外,各层土壤的p H值为7.57~8.04,且从表层到底层依次递增。根据土壤类型划分标准,该区域1.5 m土体内的土壤均已发生碱化。不同土层的土壤养分差异较大,变异系数在61.2%~101.5%,且有机质贫乏,供氮能力差,有效磷空间变异强度大。填海区绿地土壤存在轻微的盐碱化、养分含量低且空间异质性大,因此利用时应注意降碱和培肥。

2005-2018年中国科学院桃源农业生态试验站水稻根系生物量及水稻根系元素含量数据集

水稻根系残留于土壤,是水稻土有机质来源的主要因素之一,也是水稻土有机碳含量保持一定稳定性的重要因素。本数据集来源于中国科学院桃源农业生态试验站长期监测样地,包括综合观测场、辅助观测场(3个施肥处理)、2个站区调查点样地2005–2018年相关数据。数据集由7个部分组成,分别是表层根系生物量(0–20 cm)、根系元素含量(全碳、全氮、全磷、全钾)、根系分布(0–10 cm、10–20 cm、20–30 cm、30–40 cm)、样地背景信息、样地肥料投入情况、采样记录、分析方法记录。数据的产生严格遵照CERN生物联网监测规范执行,数据质量由台站与分中心质控人员审核质控。本数据集为调查水稻根系对稻田土壤有机碳及氮磷钾元素的贡献,以及水稻根系对维护稻田土壤地力的作用提供可靠的基础数据。

香榧种子近成熟期各器官的养分含量及分布特征

以浙江省诸暨市不同树龄(20 a、100 a和500 a)的香榧为研究对象,于种子近成熟期分别采集香榧根、茎、叶、种子等器官样品和土壤样品,分析各器官的养分含量、分布特征及其与土壤养分的相关性,为香榧的经营管理提拱依据。结果表明:(1)香榧各器官中的有机碳(TOC)含量在395.63~524.47 g·kg^(-1),平均为448.49 g·kg^(-1),含量从大到小依次为种子>叶>茎>根,种子中的TOC含量显著高于其它各器官中的含量(P<0.05),茎中的TOC含量在不同树龄间有显著差异(P<0.05),其它各器官的TOC含量在不同树龄间的差异不显著(P>0.05)。(2)香榧各器官的全氮(TN)、全磷(TP)、全钾(TK)含量的平均值分别为21.48、2.85、14.55 g·kg^(-1)。其中,20 a树龄香榧各器官中的TN含量从大到小依次为叶>种子>根>茎,TP含量为种子>茎>叶>根,TK含量为种子>根>茎>叶;100 a和500 a树龄香榧各器官中的TN含量从大到小依次为种子>叶>根>茎,TP含量为种子>根>茎>叶,TK含量为种子>叶>茎>根。(3)器官对香榧TOC、TN、TP、TK含量的影响达显著水平(P<0.05),树龄对香榧TOC含量的影响达显著水平(P<0.05),而对香榧TN、TP、TK含量的影响不显著(P>0.05)。(4)香榧各器官中钙(Ca)、镁(Mg)含量的平均值分别为11.70、2.27 g·kg^(-1),Ca含量从大到小依次为叶>茎>根>种子,不同树龄香榧相同器官间的Ca含量均无显著差异,Mg含量在不同树龄、不同器官间均有差异。(5)香榧根、茎、叶中的养分含量与土壤养分间有显著(P<0.05)或极显著(P<0.01)相关性,而种子中的养分含量与土壤养分间的相关性均不显著(P>0.05)。(6)香榧种子近成熟期各器官的养分总量从大到小依次为TOC>TN>Ca>TK>Mg>TP,且以种子器官中的含量为最高。

Effective root depth and water uptake ability of winter wheat by using water stable isotopes in the Loess Plateau of China

A field experiment using PVC growth tubes was conducted in the Loess Plateau of China to determine the effective root depth(ERD)of winter wheat and its relationship with root distributions and soil water conditions.The water stable isotopes technique was used to estimate the water uptake contributions of different root depths during the growth stages.On the basis of IsoSource and the Romero-Saltos model,the ERD was 0-40 cm in the majority of the growth stage.However,in the heading and filling stages,the ERD could reach 60%-75%of the maximum root depth.Furthermore,the contributions to water uptake of different root depths were correlated with variations in soil water and root length density(r=0.395 and 0.368,respectively;p<0.05).However,by path analysis,the low decisive coefficient indicated that root distribution and soil water content did not always follow the same trend as water uptake.The conclusions of this study can help with understanding winter wheat water uptake mechanisms in arid and semi-arid regions and increasing water use efficiency.

高原夏菜种植基地土壤养分含量及分布特征

【目的】旨在掌握高原夏菜种植基地土壤肥力水平及土壤养分分布特征。【方法】以甘肃省榆中县高原夏菜种植区域为研究对象,采用调查研究的方法,利用土壤养分速测仪和农业环境测定仪对高原夏菜种植基地土壤养分进行测定,结合地统计学、地理信息系统(GIS)技术、Kriging插值分析等对土壤养分质量进行分析。【结果】土壤速效磷(AP)、速效钾(AK)变异系数>100%,属于强度变异,碱解氮(AN)、全氮(TN)、全磷(TP)、全钾(TK)、电导率(EC)和有机质(OM)变异系数介于10%~100%,属于中等强度变异;土壤养分最优半方差模型为线性、球形及高斯模型,TN、AP、TP、AK、OM块金效应大于75%,空间相关性较弱,TK块金效应介于25%~75%,TK系统空间相关性为中等;AN呈中部高、四周低,TP分布情况为四周高、中部低,EC、AK分布情况为北部高、南部低,TK、OM分布情况为南部高、北部低,TN、AP呈多峰分布,经Kriging交叉验证结果较为可靠;高原夏菜种植基地7种蔬菜种植地土壤类型肥力水平均为中等,TN、AP、TP、OM含量水平为丰富,AN含量水平为中等,AK、TK含量水平为缺乏。【结论】榆中县高原夏菜种植基地各土壤养分含量差异较大、分布不均,土壤肥力水平中等,钾元素含量低下。因此,在实际生产过程中应注意根据土壤肥力水平及土壤养分分布对不同品种高原夏菜进行合理施肥与轮耕。

旱地高产小麦品种籽粒氮含量与产量形成及氮磷钾吸收分配的关系

【目的】明确高产小麦品种间籽粒氮含量差异及其与产量形成和氮磷钾养分吸收、转移及分配的关系,为旱地高产高氮含量的优质小麦品种选育和小麦丰产优质绿色生产的养分管理提供依据。【方法】于2017—2022年,以14个产量相近、籽粒氮含量差异显著的高产小麦品种为供试材料,在陕西黄土高原旱地连续5年开展田间试验,研究小麦籽粒氮含量差异及其与产量、产量三要素和各器官氮磷钾养分含量的关系,并分析高产高籽粒氮含量小麦品种的生物量累积、产量构成和氮磷钾吸收、转移及分配对施肥的响应。【结果】小麦品种的籽粒氮含量与千粒重显著正相关,籽粒千粒重每增加1.0 g,籽粒氮含量增加0.3 g·kg^(-1)。高产小麦品种间籽粒氮含量差异显著,高氮品种籽粒含氮量平均为24.9 g·kg^(-1),比低氮品种(21.5 g·kg^(-1))高16%。高产高氮品种产量、生物量和穗数在施氮和施磷后增加幅度均高于低氮品种。高产高氮小麦品种籽粒含磷量和茎叶含钾量在不同施肥条件下均高于低氮品种,籽粒和地上部氮磷钾吸收量在施氮和施磷后增幅均高于低氮品种。高产高氮品种颖壳向籽粒转移氮的能力高于低氮品种,茎叶向籽粒和颖壳转移钾的能力却低于低氮品种,施氮后茎叶向籽粒和颖壳转移钾的能力大幅下降。施氮、磷和钾均有利于提高高产高氮小麦品种地上部向茎叶的钾素分配。【结论】高产小麦品种间籽粒氮含量存在显著差异,其中高籽粒氮含量品种的千粒重、籽粒含磷量和茎叶含钾量较高,茎叶向籽粒和颖壳转移钾的能力低,籽粒和地上部氮磷钾吸收量对施氮和施磷响应更敏感。因此,在高产的基础上,选育高籽粒氮含量的优质小麦品种,应关注高千粒重、磷向籽粒和钾素向茎叶转移分配能力强的材料,在生产中应注意磷钾与氮的协同供应,以提高小麦籽粒氮含量。

毛竹林下七叶一枝花各器官养分含量及分配格局

以毛竹林下人工种植的七叶一枝花为试材,研究分析了植株花期各器官的养分含量及分布特征。结果表明:七叶一枝花各器官中的氮含量从高到低依次为叶>花>须根>块茎>茎,叶含量最高,其次为花,磷含量依次为花>叶>茎>须根>块茎,花含量最高,其次为叶,钾含量依次为须根>叶>花>茎>块茎,须根含量最高,其次为叶和花,钙含量依次为茎>须根>块茎>叶>花,镁含量依次为须根>叶>花>块茎>茎;各器官养分含量的平均值从大到小依次为氮>钾>钙>镁>磷,叶片中的N∶P平均为15.34;各器官养分含量间的相关性分析表明:须根中氮含量与钾含量、茎中钾含量与钙含量呈极显著正相关(P<0.01),块茎中的镁含量与钙含量、叶中和花中的磷含量与钾含量呈显著正相关(P<0.05),其余指标间的相关性均未达显著水平。从毛竹林下七叶一枝花的养分含量及化学计量特征来看,氮和磷可能是限制七叶一枝花花期生长的主要营养元素。建议在花期可通过配施氮肥和磷肥,提高土壤养分的供应能力,同时七叶一枝花主要是以收获地下块茎为培育目标,可根据需要摘除花蕾以减少养分消耗。

小麦根系生理活性时空分布与土壤有效养分的关系

为了解小麦根系生理活性时空分布与土壤有效养分含量的关系,在2019-2021年两个小麦生长季,于小麦的不同生育时期采用长方体铁盒(0.2 m×0.05 m×0.2 m)在麦行上、行距1/4处、行距1/2处分别取0~0.2 m和0.2~0.4 m土层的样品,测定不同位点小麦根系生物量、根系活跃吸收面积、根总吸收面积、根系活力,以及土壤碱解氮、有效磷和速效钾含量。结果表明,0~0.2 m和0.2~0.4 m土层中小麦根重密度、根总吸收面积和根系活跃吸收面积随生育时期的推进均呈先升后降的变化趋势;根系活力、根群生理势均呈“低-高-低-高-低”的变化趋势。0~0.2 m土层的根重密度、根总吸收面积、根系活跃吸收面积、根群生理势均显著高于0.2~0.4 m土层。在灌浆之前,0~0.2 m土层根系活力高于0.2~0.4 m土层;在灌浆到成熟期间,下层根系的根系活力显著增大。在整个生育期内,0~0.2 m土层中根重密度、根总吸收面积、根系活跃吸收面积和根群生理势的水平分布表现为行上>行距1/4处>行距1/2处;开花期之前,根系活力在行距1/4处最大,开花到成熟期间根系活力水平分布表现为行距1/2处>行距1/4处>行上;0.2~0.4 m土层中,小麦根系分布较均匀。整个生育时期内,0~0.2 m和0.2~0.4 m土层中,根重密度、根总吸收面积、根系活跃吸收面积与土壤碱解氮、有效磷、速效钾含量均呈负相关;根系活力与土壤碱解氮、有效磷、速效钾含量均呈正相关;根群生理势与土壤速效钾含量呈极显著正相关。土层越深,小麦根系吸收面积越小,根系吸收土壤养分能力则越弱;而在生育后期深层根系活力明显增大。在0~0.2 m土层中,距麦行越远,根系吸收面积越小,吸收土壤养分能力则越弱;而在小麦生育中、后期,距麦行中心线越远,根系活力越大。

小麦根系形态数量性状的时空分布及其与土壤养分的关系研究

为明确小麦根系时空分布及其与土壤有效养分含量之间的相互关系,于2020—2021年进行大田试验,采用裂区设计,主处理为品种,分别选用大穗品种周麦30和多穗品种周麦32,副处理为种植密度,设置1.2×10^(6)、2.4×10^(6)、3.6×10^(6)苗·hm^(-2)3个密度。使用长方体铁盒(20 cm×5 cm×20 cm)在麦行上、行距1/4处、行距1/2处分别取0~20 cm和20~40 cm土层的样品。分析冬前期、返青期、拔节期、开花期、灌浆期、成熟期不同位点小麦根系形态数量性状(根长密度、平均根直径、根体积、根总表面积)及土壤碱解氮、有效磷和速效钾含量。结果表明,随着生育时期的推进,根总表面积、根长密度、根体积表现为先升高后降低的单峰曲线变化趋势;0~20 cm土层平均根直径呈“W”形曲线变化趋势,20~40 cm土层平均根直径呈“V”形曲线变化趋势。小麦根系垂直分布状况表现为:0~20 cm土层中根总表面积、根长密度、根体积均显著高于20~40 cm土层;20~40 cm土层平均根直径高于0~20 cm土层。小麦根系水平分布状况表现为0~20 cm土层的小麦根总表面积、根体积、根长密度大小均为行上>行距1/4处>行距1/2处,平均根直径在行上最大;20~40 cm土层的小麦根总表面积、根长密度、根体积水平分布较为均匀,在行距1/4处略大。0~20 cm土层,中种植密度下周麦32的根总表面积、根长密度、根体积最大,低种植密度下周麦30的平均根直径最大;随着种植密度的增加,根总表面积、根长密度、根体积在行距1/4处和行距1/2处的占比逐渐增加,其中周麦32表现更为明显。整个生育时期内,0~20 cm和20~40 cm土层的根长密度、根总表面积与土壤碱解氮、有效磷、速效钾含量均呈极显著负相关关系;平均根直径与土壤碱解氮、有效磷、速效钾含量均呈显著正相关关系,此外,在0~20 cm土层,根体积与土壤碱解氮、有效磷、速效钾含量呈负相关关系,在20~40 cm土层,根体积与土壤有效磷含量呈极显著负相关关系。综上所述,上层(0~20 cm)麦田根系的水平分布表现为距麦行越远根系越少;而土壤有效养分含量则表现为距麦行越远养分含量越高。周麦32种植密度为2.4×10^(6)苗·hm^(-2)时根量最大;随着种植密度的增加,距麦行越远处的根量占比越大,周麦32表现尤为明显。本研究结果可为协调土壤养分供应与小麦养分需求之间的时空差异,提高土壤养分吸收利用效率提供理论依据。

基于GIS的土壤养分空间分布特征及肥力评价

了解胶州市李哥庄镇北部18个村耕地土壤养分状况,为科学设置施肥方式和高标准农田建设中土壤改良工作提供参考依据。对研究区进行土壤养分含量检测,共设置43个采样点,测定土壤pH、有机质、全氮、碱解氮、有效磷、速效钾的含量。运用ArcGIS的普通克里金插值法分析研究区土壤养分空间分布特征,通过主成分分析法确定指标权重,通过指数和法划分土壤肥力等级并将结果可视化。结果表明:(1)研究区土壤主要呈酸性和中性;有机质、全氮、碱解氮含量缺乏,有效磷含量丰富,速效钾含量中等。(2)从空间分布特征看,pH呈南北低中部高,东侧低西侧高;有机质、全氮、碱解氮含量分布呈东侧高西侧低,表明三者具有显著相关性;有效磷分布呈东侧低西侧高;速效钾分布呈东侧高西侧低的特点。(3)Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ级土地面积分别为365.11、545.80、803.71、547.93、390.85 hm^(2),占研究区总面积的13.76%、20.57%、30.29%、20.65%、14.73%。胶州市李哥庄镇北部18个村整体土壤肥力处于中等水平,土壤肥力呈现东侧丰富、西侧缺乏的特点。治理土壤酸化并提高有机质、全氮、碱解氮含量,对下一步建设高标准农田具有重要意义。

自由空气CO_2浓度升高对水稻营养元素吸收和籽粒中营养元素含量的影响

利用FACE(Free-AirCarbon-DioxideEnrichment)平台技术,用水培试验研究了低氮(14mg/L)和常氮(28mg/L)水平下,大气CO2浓度升高对水稻(OryzasativaL.)N、P、K、Ca、Mg、Cu、Zn、Fe、Mn的吸收和在植株不同部位的分配,并着重分析了CO2浓度升高对稻米中营养元素含量的影响。结果表明,按照当前CO2浓度条件下营养元素的正常供应水平,而且各元素都以有效态供给时,CO2浓度升高对多数被测元素吸收总量影响不大,只增加了K、Ca、Fe的吸收总量;N、P、Mg、Mn向穗部分配增加,K、Ca、Cu、Zn、Fe向穗部的分配比例不变;水稻籽粒中P、Ca、Mg、Cu、Zn、Fe和Mn含量无显著影响,N、K含量显著下降。还初步探讨了CO2浓度升高对稻米中人类必需营养元素的不足(或“隐性饥饿”)的影响。

甘薯的氮磷钾养分吸收及分配特性

探明宁紫1号甘薯的氮磷钾养分吸收和分配特性,为合理施肥提供依据。该研究在田间进行,设5个处理3次重复,从甘薯栽插成活到成熟收获期间,每隔15 d取1次植株样,茎叶和根分别称重、烘干,分析氮磷钾养分含量。结果表明:每生产1 000 kg鲜薯需要吸收的氮磷钾总量为11.24 kg,氮磷钾比例为1.00∶0.69∶2.32;不同生长阶段甘薯的氮磷钾养分累积特征明显不同,氮的吸收主要集中在甘薯生长中前期(移栽后60 d内),生长后期由于落叶使累积量反而下降,磷钾的吸收90%以上发生在甘薯生长的中后期(移栽后30 d至成熟);累积在甘薯茎叶和块根中氮磷钾总量相近,但累积在茎叶中的氮和块根中的磷钾偏多,累积在茎叶中氮磷钾的比例为1.00∶0.60∶2.03,块根中为1.00∶0.82∶2.69;移栽后60～75 d是宁紫1号甘薯"源-库"关系的过渡期。