科尔沁沙地固定沙丘土壤氮素空间分布特征研究

为了研究固定沙丘土壤N素空间分布特征,选择以栽植小叶锦鸡儿25年后的固定沙丘为研究对象,从迎风坡、顶坡和背风坡3个位置4个层次(0～5、5～10、10～20和20～40 cm)进行取样分析.研究结果表明:全N、NO_3~--N和NH_4~+-N含量均随着土层加深而呈现出减少的趋势,0～5 cm土层显著高于其他各层.表层土壤受凋落物的影响较大,从而相对于深层土壤来说积累了更多的N素.全N、NO_3~--N和NH_4~+-N含量在不同坡位间存在显著差异(p＜0.01):全N和NO_3~--N含量在迎风坡较高,而NH_4~+-N含量在背风坡较高.丛下全N、NO_3~--N和NH_4~+-N的含量显著高于丛间(p＜0.01).土壤电导率与全N、NO_3~--N、NH_4~+-N含量呈显著正相关,而pH与NO_3~--N、NH_4~+-N含量呈显著负相关,NO_3~--N、NH_4~+-N的富集降低了土壤pH值.小叶锦鸡儿的栽植对沙土改良具有重要意义.     

氮肥基追比对小麦产量、土壤水氮分布及利用的影响

为解决区域土壤质地类型针对性氮肥施用问题,在轻壤土和黏壤土上分别设置不施氮肥,氮肥基追比3∶7,4∶6,5∶5,6∶4和7∶3处理,研究小麦产量、水氮利用效率以及土壤含水量、贮水量、NH_4~+-N、NO_3~--N动态变化规律。结果表明:轻壤质土壤氮肥基追比4∶6的处理小麦产量、水分利用效率、氮肥生产效率最高分别为8 265.3 kg/hm~2,27.6 kg/(hm~2·mm),34.4 kg/kg。黏壤质土壤氮肥基追比5∶5的处理小麦产量、水分利用效率、氮肥生产效率最高分别为8 363.2 kg/hm~2,28.3 kg/(hm~2·mm),34.8 kg/kg。小麦不同生育期各土层含水量垂直分布变化较大,轻壤质土壤含水量在9.3%～26.2%,而黏壤质为9.7%～27.6%;小麦全生育期内土壤贮水量呈先升高后降低趋势,黏壤质土壤贮水量高于轻壤质。氮素追施量越多土壤表层NH_4~+-N与NO_3~--N含量越高,且随土层加深土壤NH_4~+-N与NO_3~--N含量降低,受降水影响轻壤质土壤NH_4~+-N与NO_3~--N更易于向土层深处淋溶,成熟期黏壤质各土层的NH_4~+-N和NO_3~--N含量均多于轻壤质。说明黏壤质土壤保水保氮肥能力强于轻壤质,氮肥基追比可以适当增加。     

不同施氮水平对深层包气带土壤氮素淋溶累积的影响

为研究深层包气带土壤中氮素的迁移规律,采用田间小区试验,研究了不同施氮水平(142.5、285和427.5kg/hm2)对夏玉米种植期间0～500cm包气带土壤中氮素淋溶累积的影响。结果表明,不同施氮水平对NO3--N、NH4+-N和总氮有显著影响,施氮越多,NO3--N、NH4+-N和总氮在土壤中的淋溶累积也就越多,夏玉米生育期间土壤中氮素的淋溶累积含量随着夏玉米生长逐渐减少。在0～200cm土层中,收获后不同施肥水平土壤中NO3--N和总氮累积量随施氮量增加而增多,285kg/hm2施氮水平NH4+-N累积量最多,427.5kg/hm2施氮水平NH4+-N累积量最少,但相差不超过0.1kg/hm2,收获后土壤中氮素累积量有损失。夏玉米生育期间不同施氮水平对土壤NO3--N、NH4+-N和总氮的影响深度主要为0～145cm。粉砂壤土中氮素更易累积,砂质壤土中氮素较易随水分淋溶至下层。142.5kg/hm2施氮水平可有效减少NO3--N在土壤中的淋溶损失,降低土壤中NH4+-N和总氮的含量,对地下水构成的潜在污染风险最小。北京地区地下水埋深较深,NO3--N不易淋溶至地下水,但长期大量施用氮肥、田间土壤大孔隙的存在等会加速NO3--N向深层土壤迁移,对地下水水质构成威胁。     

施用磷肥对土壤NO3——N累积的影响

在黄土高原南部的国家黄土肥力和肥料效益监测基地进行的长期定位试验结果表明 ,在小麦 玉米轮作中 ,当年施氮量为N 352kg/hm2 时 ,单施氮肥或氮钾配合的 0～4m土壤剖面的NO3--N累积量达 1000kg/hm2 以上 ,其中约 50%～60%的NO3--N分布在 2～ 4m以下的土层中 ,而氮磷配合的 0～ 4m土壤剖面的NO3--N累积量仅为 220kg/hm2,且 80 %的NO3--N分布在 0～2m的土层中 ,增施磷肥由于增加了氮的吸收和对水分的利用而有效地降低了土壤中NO3--N的累积。     

黄土区退果还耕对黑垆土硝态氮积累和迁移的影响

在黄土高原沟壑区王东沟小流域,针对塬面、梁地和坡地三种地形,分别选取了盛果期果园、老果园和退果还耕地等,研究了退果还耕条件下,三种地貌类型土壤剖面中水分含量变化及NO3--N、NH4+-N积累和迁移规律。结果表明,无论塬面、梁地或者坡地上,果园土壤水分含量显著降低（10%～14%）;果园退耕后,土壤水分开始缓慢恢复。盛果期,塬面NO3--N峰值主要处于100—200 cm之间,退果还耕后,100 cm以上土层中NO3--N含量降低,100 cm以下NO3--N积累量在增加,并且峰值不断向下移动。盛果期果园NO3--N积累量为631～3032 kg/hm2;退果还耕地、老果园NO3--N积累量都显著高于盛果期果园。盛果期40%以上的NO3--N积累在100—200 cm土层,但退果还耕地上50%左右集中分布在200—300 cm土层。土地利用与管理方式的变化对NH4+-N分布特征的影响并不明显。     

祁连山哈溪林区移植前后土壤氮对比研究

研究不同海拔梯度森林土壤氮的分布特征,对于合理利用森林资源、改善森林的生态功能都有重要意义。采用封顶埋管法,对祁连山东段哈溪林区不同海拔梯度和不同植被类型的土壤氮进行了研究。结果表明:(1)海拔2 650m青海云杉林土壤的初始TN,NH_4~+-N和NO_3~--N含量均最低,海拔2 950 m青海云杉林土壤的初始TN,NH_4~+-N和NO_3~--N含量均最高;各海拔梯度青海云杉林土壤经培养后,其TN,NH_4~+-N和NO_3~--N含量均减小。(2)就不同植被类型而言,青海云杉林土壤TN,NH_4~+-N和NO_3~--N含量均最高,草地和灌丛土壤TN,NH_4~+-N和NO_3~--N含量较低,且二者差异不大。草地和灌丛土壤培养后TN和NH_4~+-N含量显著升高,NO_3~--N含量变化不大。(3)某一海拔青海云杉林土壤移植到其他海拔青海云杉林培养后,土壤TN,NH_4~+-N和NO_3~--N含量变化不大;不同植被类型之间土壤相互移植培养后,土壤TN,NH_4~+-N和NO_3~--N含量变化明显,不同植被类型对土壤氮的含量差异显著。     

黄土高原丘陵沟壑区植被恢复过程对土壤剖面矿质氮累积影响--以纸坊沟流域试验区为例

根据不同植被类型和不同植被恢复年限,在位于半干旱黄土高原丘陵沟壑区延安安塞纸坊沟流域采集68个剖面样品,探讨植被恢复过程土壤剖面中残留矿质态氮的变化;同时采取该流域连续14年施用不同肥料处理的坡地长期定位试验剖面土样,研究连续施肥对农田土壤剖面残留NO3--N累积的影响。结果表明,NH4 -N在土壤剖面中的分布和累积基本不受植被恢复及植类型的影响,但NO3--N在土壤剖面中的累积量随植被恢复而下降。林地、草地和农田0～50cm土层平均累积的NO3--N分别为17 4kg/hm2,14 9kg/hm2和39 9kg/hm2;林地和草地剖面中NO3--N累积量所占矿质氮总累积量比例远小于NH4 -N,而对农田土壤,剖面中NO3--N累积量所占比例与NH4 -N所占比例基本相当;农田土壤剖面中NO3--N累积量所占比例显著大于林地和草地。长期定位试验结果进一步证明了在农田连续施用氮肥会显著增加土壤剖面中残留NO3--N累积,当农田退耕还林还草后,累积的这一部分NO3--N因植物吸收利用、土壤生物固定和损失等途径而下降,最终达到低而稳定的水平。     

膜孔直径对浑水膜孔灌土壤水氮运移特性的影响

通过对西安粉壤土进行4种膜孔直径(6,8,10,12cm)的浑水膜孔肥液自由入渗室内试验,观测并分析了湿润锋运移距离、累积入渗量、湿润体内水分分布以及NO_3~--N和NH_4~+-N运移特性的变化规律。结果表明:膜孔直径对浑水膜孔灌土壤水氮运移特性具有较为显著的影响。不同膜孔直径的浑水膜孔灌肥液自由入渗累积入渗量符合Philip入渗模型;湿润锋运移距离与入渗时间呈极显著的幂函数关系;在相同的入渗时间内,膜孔直径越大,湿润锋运移距离越大,单位膜孔面积累积入渗量越小,同一位置处土壤NO_3~--N和NH_4~+-N含量越大。入渗400min内,在膜孔中心附近区域NO_3~--N和NH_4~+-N含量较高,湿润体内土壤NO_3~--N主要集中分布在距膜孔中心15cm范围内,而NH_4~+-N主要集中分布在距膜孔中心8cm范围内。     

螃蟹对闽江河口互花米草湿地土壤活性养分变化的影响

为阐明螃蟹活动对湿地土壤活性养分含量变化的影响,对闽江河口湿地不同潮滩螃蟹干扰下的土壤DOC、MBC、NH_4~+-N、NO_3~--N、Fe及其价态含量特征进行测定和分析。结果表明:有螃蟹组土壤DOC和MBC含量分别为95.98,11.13mg/kg,对照组含量分别为106.99,7.54mg/kg,螃蟹组土壤DOC含量略低于对照组(P0.05),螃蟹组土壤MBC含量高于对照组(P0.05);两者含量最高值和最低值分别出现在夏季和冬季,且夏季显著高于其他季节(P0.05)。螃蟹组土壤NH_4~+-N和土壤NO_3~--N含量分别为22.45,1.08mg/kg,对照组含量分别为23.65,1.44mg/kg,螃蟹组土壤NH_4~+-N含量低于对照组(P0.05),螃蟹组土壤NO_3~--N含量低于对照组(P0.05);不同季节,土壤NH_4~+-N和NO_3~--N含量存在显著差异(P0.01)。螃蟹组土壤总铁含量略高于对照组(P0.05);螃蟹组土壤Fe2+含量显著高于对照组(P0.05);螃蟹组和对照组土壤Fe3+含量差异不明显(P0.05)。不同季节,土壤总Fe、Fe~(2+)和Fe~(3+)含量存在显著差异(P0.01)。     

黄土高原不同树龄苹果园土壤水分及硝态氮剖面特征

为揭示黄土高原农田转变为苹果园后土壤水分及硝态氮剖面变化特征,以洛川县为研究区,采集农田(对照)和8,17,25年苹果园共40个0-600 cm剖面土样,分析土壤水分、NO3--N浓度及其储量。结果表明:与农田相比,8年苹果园0-600 cm土壤水分含量及贮水量偏高(旧县镇)或相当(槐柏镇),而NO3--N浓度及其累积量则没有显著差异;17,25年苹果园0-600 cm土层贮水量则显著降低(P<0.05),分别下降150,230 mm,且该差异主要与300 cm以下土层水分变化有关;0-500 cm土层NO3--N浓度随苹果种植年限显著增加,17,25年苹果园0-600 cm土层NO3--N累积量分别为6 830,8 370 kg/hm2,二者显著高于农田(695 kg/hm2)和8年果园(440 kg/hm2)。综合可知,农田转变为苹果园这一土地利用方式变化可导致深层土壤水分亏缺(>300 cm)和硝态氮累积,黄土高原大力发展苹果种植过程中应重视蓄水保墒及氮肥减施等措施。     

“绿色革命”以来大气CO2浓度升高对C3作物营养品质的影响

自20世纪60年代"绿色革命"以来,育种技术和农耕技术的发展促进了农作物产量的大幅提升,然而作物的营养品质出现下降趋势。在相似的遗传背景下,大气CO_2浓度升高会使单位体积农作物产品的营养元素含量下降,因此"绿色革命"至今,农作物产品的营养元素下降可能受大气CO_2浓度升高影响。通过植物生长箱模拟"绿色革命"初期和目前的大气CO_2浓度水平(310μmol/mol和400μmol/mol),针对主要C_3作物水稻、小麦和大豆,研究"绿色革命"以来大气CO_2浓度升高对其籽粒的C、N、Fe、Zn元素含量的影响,结果表明:CO_2浓度升高对3种作物籽粒的C元素含量几乎没有影响,变化幅度在±1.5%之间;籽粒的N、Fe、Zn元素含量普遍呈现下降趋势,但均未达到显著水平。     

Potential of wild species for genetic enhancement of some semi-arid food crops

Discovery and incorporation of genes from wild species provide means to sustain crop improvement, particularly when levels of resistance in the cultigens are low and virulent strains of pests and pathogens overcome the host plant resistance. The extent of utilization and the potential of the wild genepool for genetic enhancement were reviewed in five important food crops viz. sorghum, pearl millet, chickpea, pigeonpea and groundnut grown in the semi-arid tropics. Introgression from compatible wild germplasm in the primary gene pool resulted in transfer of new cytoplasmic male sterility systems in pearl millet and pigeonpea, development of high protein, cleistogamous flower and dwarf pigeonpea lines and foliar disease resistant groundnut cultivars. Utilization of wild species in secondary and tertiary gene pools has been generally limited due to sterility, restricted recombination or cross incompatibility. Nevertheless, these species are extremely important as they contain high levels of resistance to several important biotic and abiotic stresses. Several of them, like those belonging to the Parasorghum section and the rhizomatous Arachis species are sources of multiple resistances and hold great promise to sustain crop productivity.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications     

Soil-profile distribution of primary and secondary plant-available nutrients under conventional and no tillage

Nutrient distributions under no tillage (NT) compared with conventional disk-and-bed tillage (CT) management in the warm, humid region of the southeastern USA need to be assessed so that future placement, quantity, and type of fertilizers can be altered, if necessary, to efficiently match crop demands. We determined soil-profile distributions of pH, N, P, S, K, Ca, Mg, Na, Zn, Fe, Mn, and Cu to a depth of 0.9 m at the end of 8.5 years of continuous CT and NT management on a Weswood silty clay loam (fine, mixed, thermic Fluventic Ustochrept) in southcentral Texas. Most dramatic changes occurred within the 0–0.05 m depth, where soil under NT had lower pH, Fe, and Cu than under CT, but greater P, K, Zn, and Mn. Greater P and K under NT than under CT also occurred below the till-zone (0.15–0.3 m). At a depth of 0–0.3 m, soil under NT contained greater amounts of extractable P, K, Zn, Fe, Mn, and Cu than under CT. Nitrogen fertilization had little effect on nutrient distributions, except resulting in greater extractable K at 0–0.05 m and greater nitrate at 0–0.15 m. Few changes in soil-profile distributions were observed for extractable S, Ca, Mg, and Na. Long-term continuous use of NT on this fine-textured, high-fertility (except for N) soil had no apparent adverse effects on nutrient distributions relative to CT, but enhanced conservation and availability of P, K, Zn, Fe, Mn, and Cu near the soil surface where crop roots proliferate.     

Assessing the effectiveness of conservation measures: Resolving the “wicked” problem of the Steller sea lion

“Wicked” problems are those that are complex and that change when solutions are applied. Many conflicts in conservation fall into this category. The study approached the problem of how to constrain the apparent wickedness of a problem in the conservation management of a species by using simple empirical indicators to carry out iterative assessment of the risk to a population and to document how this risk evolves in relation to the addition of new data and the implementation of management actions. Effects of high levels of uncertainty within data and also concerning population structure were examined through stochastic simulation and by exploration of scenarios. Historical trends in the example used, the Steller sea lion, showed rapid declines in abundance in some regions during the 1980s. The current total population is 130,000-150,000 Steller sea lions through Alaska and British Columbia and this number has been stable since about 1990 in spite of regional differences in population dynamics. Regional differences in the sequence of changes in the number of pups and non-pups, suggested that an internal re-distribution of juveniles could have happened between 1980 and 1990. Current productivity also appears close to the long-term mean. Stochastic population projection using various scenarios showed that, based upon this history, the risk of extinction for the population has declined and is below reasonable thresholds for considering the population to be endangered. The trends in risk suggest that management actions taken since 1990 have probably been effective. Consequently, the conservation management objectives for the Steller sea lion are probably being met. The approach provides a mechanism, based upon experience and scenario analysis, for exploring future policy options and may help to constrain the debate amongst stakeholders about the cost-benefit trade-offs associated with different options.     

Collection and preliminary evaluation of native turfgrass accessions in Italy

Despite a raising interest on turfs in Italy, all theavailable varieties of this kind in the Country are of foreign origin, and areoften poorly adapted to the prevailing climatic conditions. This prompted tobegin a collection activity of indigenous turfgrass species, with the ultimategoal of identifying promising materials for future breeding based on localgenetic resources. The collection was carried out in three areas of Italy, viz.the northern Po Plain, the coastal region of Liguria, and the island of Sardiniathat are characterised, respectively, by subcontinental, warm temperate, andtypical Mediterranean climate. Altogether, 141 sites were visited, yielding 226accessions belonging to eight species of potential interest for turfs:Poa pratensis, Poa trivialis,Festuca rubra, Festuca arundinacea,Lolium perenne, Agrostis stolonifera,Agrostis tenuis, and Cynodon dactylon,this last being a warm-season grass. Poa pratensis andCynodon dactylon were mostly collected in northern Italyand Sardinia, respectively, whereas Festuca arundinacea andLolium perenne were rather ubiquitous. The collection sitesranged from 0 to 1040 m asl, but sites over 750 m wereonly visited in the inner part of Sardinia. All the accessions, collected aswhole plants, were transplanted at Lodi, northern Italy, where they are beingevaluated. Their preliminary evaluation for traits of importance for turf use,such as sward colour and overall quality, highlighted the great variation andthe occurrence of interesting accessions in all species. Other characters wererecorded, bearing specific importance in individual species, and in all casespromising accessions were identified. The germplasm of Festucarubra, Festuca arundinacea, and Loliumperenne proved highly infected by endophytic (symbiotic) fungi of thegenus Neotyphodium.     

Enhanced establishment and growth of giant cardon cactus in an eroded field in the Sonoran Desert using native legume trees as nurse plants aided by plant growth-promoting microorganisms and compost

To evaluate the feasibility of long-term desert reforestation technology of mixed vegetation, cardon cactus (Pachycereus pringlei) seedlings from indoor and outdoor nurseries were planted in the field adjacent to one seedling of potential legume nurse trees: mesquite amargo (Prosopis articulata), yellow palo verde (Parkinsonia microphylla), and blue palo verde (Parkinsonia florida). Some of the planting holes were also supplemented with common dairy compost. Additionally, the combinations of legume tree–cactus were inoculated with either a consortium of desert arbuscular mycorrhizal (AM) fungi, plant growth promoting bacteria (PGPB; the diazotroph Azospirillum brasilense Cd, and the phosphate solubilizer Paenibacillus sp.), or a mixture of all. The field experiments were evaluated periodically during 30 months for survival and growth. Cardons reared in an outdoor screen house survived better in the field than those reared in a controlled growth chamber and hardened later outdoors. Association with any legume nurse tree increased survival and enhanced growth of untreated cardons. For cardons growing alone, application of either compost, AM fungi, and all the treatments combined increased survival. For these plants, no treatment affected plant growth during the first 3 months after transplanting. Later, all treatments, except for AM fungi, enhanced plant growth. However, only 2 years after transplanting the enhanced growth effect of AM fungi was also significant. In the presence of the legume nurse trees, transient positive effects on cardon growth were recorded. General evaluation after 30 months of cultivation showed that the treatments positively affected cardon growth when growing alone or in combination only with mesquite amargo but not with the other two legume trees. This study proposes that young legume trees have the capacity to enhance survival and growth of cardon cactus, depending on the legume cactus combination. Additional treatments such as compost or PGPB can either amplify the effect or else attenuate it.     

Karyotypic and genome size variation in Cajanus cajan (L.) Millsp. (pigeonpea) and some wild relatives

Detailed karyotypes and 4C DNA amounts have been studied in five cultivars of Cajanus cajan and 20 species belonging to Cajanus, Rhynchosia, Dunbaria, Flemingia and Paracalyx. C. cajan shows intraspecific variability and its karyotype is most similar to that of C. cajanifolius (sect. Cajanus) in the morphology and number of satellite chromosomes and the lack of any correlation between chromosome size within the complement and asymmetry. Karyotypes of C. lineatus and C. sericeus belonging to sect. Atylia are similar with respect to maximum r-index and the ratio of longest and shortest chromosomes in their respective complements. C. acutifolius (sect. Frutocosa) is distinct in having a very low ratio (1.44) between the longest and the shortest chromosomes, while in C. albicans, C. goensis, C. scarabaeoides (sect. Cantharospermum) there is no chromosome pair with r-index >2.0. C. mollis and C. volubilis (sect. Volubilis) show similarity with regard to ratio between the longest and the shortest chromosomes and a distinct chromosome pair with an arm ratio of 2.7 and C. platycarpus is distinct (sect. Rhynchosoides) in having the smallest ratio (1.36) between the longest and the shortest chromosomes. 4C DNA amounts in Cajanus and Rhynchosia vary between 3.28 pg to 11.69 pg and 4.92 pg to 11.13 pg respectively, while in Dunbaria, Flemingia and Paracalyx these vary between 4.70 and 7:06 pg. In the genus Cajanus karyotypic features and 4C DNA amounts agree with the sectional classification and bring out a close relationship between C. cajan and C. cajanifolius. This is supported by studies based on seed protein patterns, isozyme analysis, trypsin and chymotrypsin inhibitor patterns, RFLP and RAPD data and crossability relationships. A clear relation between DNA amount and abnormalities effecting the extent of pairing and recombination in interspecific hybrids shows the importance of this study in developing future breeding programme involving C. cajan and its wild relatives that are of potential value.     

Effect of some fungicide seed treatments on the survival of Bradyrhizobium japonicum and on the nodulation and yield of soybean [Glycine max. (L) Merr.]

Several commercial fungicide seed treatments were evaluated for their possible effect on the survival of Bradyrhizobium japonicum on seeds and on the nodulation and yield of soybeans in a greenhouse and a field experiment. quinolate Pro (carbendazim and oxine copper), Vitavax 200FF (carboxin and thiram), and Monceren (pencycuron) had a small effect or no effect on the survival of B. japonicum and on the nodulation and yield of soybeans. They can thus be considered compatible with soybean seed inoculation. Germipro UFB (carbendazim and iprodione), Apron 35J (metalaxyl), and Tachigaren (hymexazol) decreased B. japonicum survival and the nodulation and yield of soybeans and thus cannot be considered compatible with soybean seed inoculation.     

Leaf position and genotype differences for mineral element concentrations in sorghum grown on tropical acid soil 1

Mineral element deficiencies and toxicities are common problems associated with sorghum [Sorghum bicolor (L.) Moench] production on acid soils. To better understand some of the mineral element problems and the analysis of plant tissue of sorghum plants grown on acid soils, four sorghum genotypes were grown on an acid Oxisol at Carimagua, Colombia limed with dolomite at 2 and 6 Mg ha^‐1.

Samples for mineral element analyses were obtained from leaves at different positions on the four genotypes. Concentrations of P and Mg were highest in the flag leaf (Leaf No. 1) and decreased as the position on the plant declined from the top of the plant for plants grown at 2 Mg lime ha^‐1. Similar decreases in P, Mg, K, and Zn concentrations occurred in plants grown with 6 Mg lime ha^‐1. Concentrations of Ca, S, Si, Mn, Fe, Cu, and Al increased as leaf position declined from the flag leaf for plants grown at 2 and 6 Mg lime ha^‐1. The higher lime supply enhanced Ca and reduced Mn and Fe concentrations in leaves. Differences in mineral element concentrations for the four genotypes used were fairly extensive. The elements to show the greatest range among genotypes were Al and Si and the elements to show the least range among genotypes were P, K, and S. Care should be used in collecting leaf samples for plant analysis and genotypic differences for accumulation of mineral elements should be considered in interpretation of results.