Change of Zinc Forms in Rhizosphere and Nonrhizosphere Soils of Maize (Zea mays L.) Plants as Influenced by Soil Drought Condition

A rhizobox experiment was conducted to study the changes of various zinc (Zn) forms in rhizosphere and nonrhizosphere soils of maize (Zea mays L.) plants grown under well-watered and drought conditions. The tested soil was earth-cumulic orthic anthrosol sampled from the Shaanxi Province of China. The experiment was set at two levels of Zn, 0 and 5.0 mg Zn kg^?1 soil, and at two treatments of soil water content, 45%–50% (drought) and 70%–75% (well watered) of soil water-holding capacity. A completely randomized factorial design (2 Zn treatments × 2 water levels × 3 replicates) was set up. Adequate soil water supply enhanced growth and Zn accumulation of maize plants. Applying Zn increased plant biomass and Zn content more notably under well-watered conditions rather than drought conditions. Soil Zn was defined as water-soluble plus exchangeable (WSEXC) Zn, carbonate-bound Zn (CA), iron–manganese oxide–bound Zn (FeMnOX), organic matter–bound Zn (OM), and residual Zn (RES) forms using the sequential extraction procedure. Most of Zn was predominantly in the RES fraction. Zinc application increased the contents of WSEXC Zn, CA Zn, and FeMnOX Zn in soil. When Zn was added to the soil, the concentrations of CA Zn within 0–2 mm and 0–4 mm apart from the central root compartment (CC) were greater than other zones under the conditions of adequate and limited soil water supplies, respectively. Zinc application also resulted in an accumulation of FeMnOX fractions at a distance of 2 mm from CC. The FeMnOX Zn content in this compartment increased with soil drought. Under well-watered conditions, dry-matter weight and Zn concentration of shoots presented better correlations with CA Zn and FeMnOX Zn fractions in and near the rhizosphere as compared with drought conditions. It is suggested that in an earth-cumulic orthic anthrosol, soil moisture conditions affect the transformation of the added Zn into the CA and FeMnOX fractions near the rhizosphere and their bioavailability to maize plants.     

玉米单倍体胚性愈伤的诱导与鉴定

为建立一套适合玉米单倍体胚性愈伤培养和快速筛选体系,以单倍体诱导系MT-1为父本,18-599红为母本进行单倍体诱导,设置暗培养、全光照培养和光暗周期培养3种光照培养方式,均分别培养0、1、5、10、20、40 h后,观察幼胚形态和颜色。结果表明,自交系18-599红的单倍体和二倍体幼胚均能正常诱导形成胚性愈伤组织;不同光照培养方式对紫色(二倍体)愈伤率的检出效果依次为光培养>光暗周期培养>暗培养。通过光照筛选的方法可在早期鉴定愈伤组织,其二倍体愈伤的筛选率在培养20 h时可达68%,40 h时为71%,剔除了大部分非单倍体愈伤,综合分析确定光照强度为2 000 lx、20℃处理20 h为最适光照筛选处理。染色体压片技术获得的拟单倍体愈伤中有二倍体愈伤的检出,但经流式细胞仪检出获得的拟单倍体愈伤再经染色体压片检测,无二倍体愈伤,表明流式细胞仪检测单倍体愈伤的准确性高于染色体压片技术。通过光照初步筛选结合流式细胞仪的精确鉴定,迅速从3 000个单倍体愈伤中获得110个单倍体愈伤,单倍体愈伤率3.67%。本研究结果为以玉米单倍体愈伤为转基因受体,快速获得转基因植株提供了一定的技术支撑和理论参考。     

Characterization of Zinc Oxide Nano Particles and Their Effect on Growth of Maize (Zea mays L.) Plant

In the current literature, the impact of nano-particles (NPs) on growth of higher plants has scantly been reported. An investigation was carried out to study the effect of zinc oxide nano-particles (<100 nm) on growth of maize (Zea mays L.) plant, as one of the major agricultural crops, in a solution culture system. Various concentrations of zinc (Zn) were applied through nano-zinc oxide (ZnO) particles (<100 nm) in suspension form and in ionic form through zinc sulfate (ZnSO₄) salt in Hoagland solution culture. Experimental results showed that nano zinc oxide particles could enhance and maintain the growth of maize plant as well as conventional Zn fertilizer (as ZnSO₄). The plant parameters like plant height, root length, root volume, and dry matter weight were all improved due to application of zinc oxide nano-particle. These findings indicate that plant roots might have the unique mechanism of assimilating nano-Zn and using for its growth and development. Different enzymatic activities were also studied and experimental results revealed that nano-ZnO particles (<100 nm) also governed the enzymatic activity of maize plant. A separate laboratory experiment was also carried out to characterize the zinc oxide nano particle for its size, zeta potential, etc.     

Effects of Lead on Iron,Manganese, and Zinc Concentrations in Different Varieties of Maize (Zea mays)

To investigate the effects of different levels of lead (Pb) on the concentration of iron (Fe), manganese (Mn), and zinc (Zn) in Zea mays, an experiment was conducted in a completely randomized design and 4 × 8 factorial arrangement with three replicates on a calcareous soil in a greenhouse. Factors included four levels of Pb (0 as control, 100, 200, and 400 mg Pb kg^?1 soil) from PbCl₂ source and eight varieties of maize (single cross 260, 301, 302, 500, 604, and 647 and double cross 370). Results showed that the accumulation of Pb was greater in roots than shoots in the maize varieties studied. Increased Pb concentration in soil decreased Mn and Fe in shoot and elevated Fe concentration in roots. The Mn concentration of roots on different levels of Pb was not affected. Zinc concentration of almost all varieties increased in shoots and decreased in roots with the increase of Pb in soil.     

Corn (Zea mays L.) Grain and Stover Yield as Affected by Soil Residual Mineral Nitrogen

Evaluation of nitrogen (N) dynamic in soil using regression equations is important for proper determination of N fertilization. A 3-year field experiment was conducted to (1) develop the best-fitted regression model relating corn grain and stover yield to soil residual ammonium (NH₄)-N and nitrate (NO₃)-N for corn yield prediction and (2) evaluate how such a model can be beneficial to the health of ecosystem by predicting the appropriate rates of N fertilization for corn production. Soil NH₄-N and NO₃-N were determined at corn harvest at the depths of 0–30 and 30–60 cm. Nitrogen fertilizer rates and soil mineral N accounted for a maximum of 93% variation in corn grain yield. Soil mineral N enhanced corn yield more than N fertilizer. Totals of 63.1 and 14.1 kg/ha of soil residual NO₃-N and NH₄-N were found in the 0- to 60-cm depth, indicating the importance of performing soil N tests.     

Interaction of Iron with Copper,Zinc, and Manganese in Wheat as Affected by Iron and Manganese in a Calcareous Soil

Iron (Fe) availability is low in calcareous soils of southern Iran. The chelate Fe-ethylenediamine di (o-hydroxy-phenylacetic acid) (Fe-EDDHA), has been used as an effective source of Fe in correcting Fe deficiency in such soils. In some cases, however, its application might cause nutritional disorder due to the antagonistic effect of Fe with other cationic micronutrients, in particular with manganese (Mn). A greenhouse experiment was conducted to evaluate the influence of soil and foliar applications of Fe and soil application of manganese (Mn) on dry matter yield (DMY) and the uptake of cationic micronutrients in wheat (Triticum aestivum L. var. Ghods) in a calcareous soil. Results showed that neither soil application of Fe-EDDHA nor foliar application of Fe sulfate had a significant effect on wheat DMY. In general, Fe application increased Fe uptake but decreased that of Mn, zinc (Zn), and copper (Cu). Application of Mn increased only Mn uptake and had no significant effect on the uptake of the other cationic micronutrients. Iron treatments considerably increased the ratio of Fe to Mn, Zn, Cu, and (Mn + Zn + Cu). Failure to observe an increase in wheat DMY following Fe application is attributed to the antagonistic effect of Fe with Mn, Zn, and Cu and hence, imbalance in Fe to (Mn + Zn + Cu) ratio. Due to the nutritional disorder and imbalance, it appears that neither soil application of Fe-EDDHA nor foliar application of Fe-sulfate is appropriate in correcting Fe deficiency in wheat grown on calcareous soils. Hence, growing Fe-efficient wheat cultivars should be considered as an appropriate practice for Fe chlorosis-prone calcareous soils of southern Iran.     

Residual effects of poultry litter on silage maize (Zea mays L.) growth and soil properties derived from volcanic ash

Abstract

Poultry litter (PL) is a cheap alternative to conventional fertilizers. The use of PL in this way also reduces the environmental problems normally associated with its disposal. The residual effect of PL may reduce the amount of fertilizer (especially N fertilizer) required by subsequent crops. This study examines the residual effects of PL (with and without additional mineral fertilizer) on the properties of a volcanic ash soil and on silage maize (Zea mays) yields in central Chile. Poultry litter and mineral fertilizer were applied in 2002–2003 and their residual effects were determined in 2004–2006. The dry matter (DM) yield, nutrient balance and apparent nitrogen recovery efficiency (ANRE) of the silage maize were determined for each season, and the soil properties were analyzed at three depths (0–20, 20–40 and 40–60 cm) at the end of the third season. Crop yield showed a positive response to all fertilizer treatments. The residual effect, the nutrient balance, N uptake and ANRE also improved with fertilizer treatment, especially with the PL treatments. The average DM yield for the PL treatments was higher than that observed using mineral fertilizer by 2.8 and 1.2 Mg ha^?1 in the third and fourth years, respectively. The ANRE was generally higher in the PL treatments, although it decreased over time (12.4 and 1.7% for the last 2 years, respectively). The mean ANREs for the mineral fertilizer treatment were 4.1 and 1.6% for the same years. The results suggest that the PL treatments had an important positive residual effect in terms of N supply. This should be taken into account when planning the next crop. After two annual applications of PL, slight increases were observed in soil NO₃-N at a depth of 0–20 cm, and extractable P at depths of 20–40 cm and 40–60 cm. No other soil variables were significantly affected by any of the treatments. An additional source of K was found to be necessary to maintain an adequate soil K level.     

Zinc Application Enhances Biological Yield and Alters Nutrient Uptake by Cotton (Gossypium hirsutum L.)

Zinc (Zn) deficiency is often associated with calcareous soils throughout the world, whereas application of Zn not only enhances biological yield but exhibits significant interactions with nutrients. Hence, a two-year field experiment was performed in 2004 and 2005 to assess the crop Zn requirements as well as nutrient interactions in cotton. The present study followed a randomized complete block design with five Zn levels: 0.0, 5.0, 7.5, 10.0, and 12.5 kg Zn as ZnSO₄.7H₂O. The biological yield of cotton increased progressively with increasing Zn rates. In general, cotton yield was higher in 2005 over 2004. Interestingly, Zn fertilization resulted in increased accumulation of nitrogen (N), potassium (K), boron (B), and Zn, whereas decreased the phosphorus (P), calcium (Ca), magnesium (Mg), iron (Fe), copper (Cu), and manganese (Mn) (p ≤ 0.05) uptake by cotton. The enhanced macronutrients accumulation in cotton by Zn application improved the cotton yield. In conclusion, biological yield and nutrient composition of the cotton plant are greatly influenced by Zn supply under irrigated environments.     

Silicon Effects on Metal Tolerance and Structural Changes in Maize (Zea mays L.) Grown on a Cadmium and Zinc Enriched Soil

Water, Air, & Soil Pollution - The southern sector of the Guadiana River basin (GRB) drains the central-western part of the Iberian Pyrite Belt, an area with many polymetallic sulfide deposits...     

Effects of Soil Fertility Management on Growth,Yield, and Water-Use Efficiency of Maize (Zea mays L.) and Selected Soil Properties

Maize was grown for two cropping years to investigate the supplementary effect of inorganic fertilizer with cow dung on growth, yield, water-use efficiency, and soil properties. Five treatments were imposed: unfertilized control and four different fertilization packages comprising two different levels of inorganic fertilization with cow dung as supplements, sole inorganic fertilizer, and sole cow dung. Results analyzed after the two cropping years showed significant differences in growth and yield. A reduction in yield was observed for the unfertilized plots, whereas yields in the plots of supplemented inorganic fertilizer with cow dung increased and were significantly at par with the sole inorganic fertilizer plot. Water-use efficiency was improved for the fertilized plots. Significant improvement was observed in the water-stable aggregates with plots that received cow dung as organic manure either in part with inorganic fertilizer or as sole cow dung.     

Maize (Zea mays L.) yield and soil properties as affected by no tillage in the black soils of China

A four-year tillage experiment on maize was conducted in the high latitude region of Northeast of China. The main objective of this study was to investigate the effects of different field tillage practices on maize grain yield, soil physical properties, and soil water and temperature dynamics in Northeast of China. The tillage practices included moldboard plow tillage (MOT), rotary tillage (ROT), reduced tillage (RET), combined tillage (COT), and no tillage (NOT). The surface soil water content at depths of 0–20 cm was higher under NOT compared with other tillage practices, but not different at the deeper soil depths in 2011. The soil temperatures under NOT and RET were lower than those under moldboard plow tillage and ROT at depths of 5 and 15 cm, respectively, measured at 9:00 am in 2005. From the hourly dynamics of soil temperature, the differences among the tillage practices mainly appeared during the daytime (from 8:00 am to 7:00 pm). Among all the practices, the average daily soil temperature under ROT was the highest, while that under NOT was the lowest. MOT, ROT, and RET had higher soil accumulative infiltration compared with NOT and COT. The surface soil bulk density under NOT was higher than or equal to that under the other four tillage practices. The maize yields under NOT were the lowest among all the tillage practices for three years straight. Meanwhile, the yields under MOT were the highest, which were about 47%, 61%, and 38% higher than those under NOT. NOT practice is not recommended for use in spring-planted maize under the high latitude humid cool climate Mollisol region in Northeast of China.     

High Sodium in Irrigation Water Caused B Toxicity at Low Soil Solution and Shoot B Concentration in Maize (Zea mays L.)

Sodium (Na) and calcium (Ca) in brackish water differentially affects boron (B) nutrition of plants grown on calcareous and salt-affected soils. A glasshouse experiment was conducted to evaluate the effect of brackish irrigation water with different sodium adsorption ratio (SAR_iw) [distilled-water control, 8, and 16 (mmol_c L^?1)^1/2] on B nutrition of maize. Plants were grown for 40 days with 5 levels of B (0, 1.29, 2.30, 3.22, and 4.46 mg kg^?1 soil). Boron application significantly improved plant growth at lower rates. High B rates and application of high SAR_iw decreased plant growth independently, and the reduction in growth was further aggravated due to combined effect of both B and high SAR_iw. Decreased growth was attributed mainly to increased shoot B and Na concentration, while decreased Ca concentration. These ionic changes also altered internal and external B requirements. Yield decrease was observed at lower B concentration in soil solution B and plants shoot grown with high SAR_iw than in plants grown with distilled water and low B application rates.     

干旱胁迫对玉米根系生长及根际养分的影响

通过盆栽模拟干旱试验，测定了干旱胁迫下玉米根系生长情况和根际土壤中速效N、P、K的含量。结果表明，干旱胁迫抑制了玉米拔节期和抽雄-开花期玉米根系的生长，减弱了玉米根系的吸收能力。干旱胁追下玉米根际NH4^＋-N、NO3^--N、速效P和速效K均发生根际富集现象。其中有效N和速效K含量高于正常供水．而速效P却呈现低于正常供水的趋势。干旱胁追抑制玉米根系生长、减弱根系吸收能力是玉米减产的重要原因。     

Zinc Concentration in Rice (Oryza sativa L.) Grains and Allocation in Plants as Affected by Different Zinc Fertilization Strategies

Concern over the food chain transfer of zinc (Zn) is increasing because of its importance in human health. A field experiment was conducted on a low Zn soil to determine the effect of different Zn fertilization strategies on grain Zn concentration and Zn allocation in different plant tissues of rice. Six treatments were used: (1) no Zn fertilization; (2) soil fertilization at transplanting; (3) Zn soil fertilization at transplanting and flowering; (4) foliar application during grain filling; (5) foliar applications during tillering, flowering, and grain filling; and (6) combination of treatments 3 and 5. Zn fertilization significantly increased Zn concentration in brown rice. The largest effect on grain Zn was observed by combination of soil and foliar applications. The increase in brown rice was much smaller (20%) than the increase in the vegetative parts (100%), indicating that grain Zn concentration of rice is not strongly increased by Zn fertilization. More increased Zn by Zn fertilization was allocated into straw not into grain. From the perspective of human nutrition, it seems that there is too little scope to enhance Zn concentration in rice by fertilization alone. the major bottleneck to increase Zn concentration in rice grain seems to be internal translocation/retranslocation of Zn from shoot to panicle or from rachis to grain, rather than root uptake of Zn from the soil.     

N-utilization by maize (Zea mays L.) as influenced by crop rotation and field pea (Pisum sativum L.) residue management

Abstract. A five year field experiment was conducted to assess the influence of crop rotation and field pea residue incorporation into the soil on maize yield. The data indicated a 30% increase in maize yield grown in rotation with field pea compared to when it was grown after wheat and a further increase of 35% when field pea residues were incorporated into the soil. The effect of field pea and residue incorporation was greater in the presence of fertilizer nitrogen indicating the enhanced capacity of the crop to utilize N from the residue. Legume residue management in sub-tropical regions of the world, having coarse textured soils low in organic matter, could help to increase the yield of cereals besides saving some of the expensive fertilizer input.     

控释钾肥对玉米产量、钾肥利用率和土壤速效钾的影响

通过玉米—小麦轮作条件下连续2年的大田定位试验,以钾空白(CK)、普通氯化钾常量(K1)、普通氯化钾高量(K2)为对照处理,研究通过控释氯化钾常量(CRK1)、控释氯化钾高量(CRK2)、氯化钾与控释氯化钾等比掺混常量(BBF1)、氯化钾与控释氯化钾等比掺混高量(BBF2)处理对玉米产量、钾肥利用率和土壤速效钾的影响。结果表明:(1)BBF2玉米-小麦季产量分别为11 697.8kg/hm2和11 921.1kg/hm2,增产和增收效果最好,较K1分别显著增产13.3%和15.7%,较K1分别显著增收16.6%和19.6%;(2)BBF2钾肥农学利用率较K1分别显著提高了49.0%和41.9%,生理利用率较K1分别显著提高了17.6%和34.8%;BBF1钾肥表观利用率最高,玉米—小麦分别为23.73%和35.22%;(3)施用钾肥显著提高了玉米的株高和茎粗;BBF2提高了玉米吐絮后期至成熟期的株高;CRK1、CRK2、BBF1、BBF2均提高了玉米吐絮后期叶片SPAD值。本试验条件下,控释氯化钾与普通氯化钾掺混施用可满足玉米整个生育期的钾素需求,提高玉米产量和钾肥利用率,BBF2处理为玉米最佳钾肥施用方案。     

Soil temperature,growth and yield of maize (Zea mays L.) as affected by wheat straw mulch

Maize crop is grown mostly in tropical/subtropical environments where drought adversely affects its production. A field experiment was conducted on sandy loam soil for four years (1999 – 2002) to study the effect of wheat straw mulch (0 and 6 t ha^?1) and planting methods (flat and channel) on maize sown on different dates. Maximum soil temperature without mulch ranged from 32.2 – 44.4°C in channel and 31.6 – 46.4°C in flat planting method. Mulching, however, lowered soil temperature by 0.8 – 7.0°C in channel and 0 – 9.8°C in flat planting. Mulching, on an average, improved leaf area index by 0.42, plant height by 14 cm, grain yield by 0.24 t ha^?1 and biomass by 1.57 t ha^?1, respectively. Mulching improved grain yield only in flat sowing. Interaction between sowing date and planting method was significant. Seasonal variation in biomass were significantly correlated (p = 0.05) with mean air temperature during 0 – 45 days after planting (DAP) (r = ?0.95), pan evaporation during 0 – 15 DAP (r = 0.79) and negative correlation with rainfall in entire cropping season (r = ?0.89), whereas biomass increase with mulch in different cropping seasons had negative relation (r = ?0.74) with amount of rain during 0 – 15 DAP.     

施用腐植酸对夏玉米产量、氮素吸收及氮肥利用率的影响

为了探究腐植酸与无机肥料配施对夏玉米产量、氮素吸收及氮肥利用率的影响,于2014年始在河南省南阳市卧龙区英庄镇开展田间定位试验,共设置单施磷钾肥、常规施肥、常规施肥+3 000kg·hm~(-2)腐植酸、常规施肥减氮15%+3 000 kg·hm~(-2)腐植酸、常规施肥减氮30%+3 000 kg·hm~(-2)腐植酸等5个处理,分析不同氮肥运筹下夏玉米产量和氮肥利用的特征。结果表明,施用腐植酸可以有效改善夏玉米的农艺性状,提高夏玉米的产量,促进植株对氮素的累积和提高氮肥的利用率。其中,以常规施肥减氮15%+腐植酸处理效果最佳,与常规施肥相比,产量增加8.68%~12.96%,籽粒氮含量、籽粒氮累积量、地上部总氮累积量分别增加2.83%~3.92%、11.75%~19.74%、8.83%~19.41%,氮肥利用率增加52.00%~116.55%。因此,常规施肥减氮15%+3 000 kg·hm~(-2)腐植酸是本研究区域最佳的施肥模式,对实现现代农业生产的高产高效、资源节约和生态环境保护具有重要意义,是值得推荐的肥料运筹方式。     

Morphology and Physiology of the Seminal Root System of Young Maize (Zea mays L.) Plants as Influenced by a Locally Restricted Nitrate Supply

In water culture the effect of a locally restricted NO₃ supply to the seminal root system of maize seedlings was studied. For this purpose plants were cultivated in containers with a wide-bore polyethylene tube positioned horizontally. Roots were suited through small holes in this tube and after sealing the holes with a non-toxic silicon putty, root segments in the tube could be exposed to a different nutrient solution from the rest of the root system in the outer compartment. In case of a locally restricted NO₃ supply (NO₃ was just supplied to the root segment within the tube), we observed an increase in root growth beginning at the fifth day after onset of the treatment. NO₃ uptake rate (¹⁵N) within the tube was significantly higher than in control plants (receiving NO₃ to the entire root system) as early as two days after onset of the treatment. One day later respiration (O₂ consumption) of the root segment exposed to NO₃ increased and at the same day we observed an accumulation of ¹⁴C activity (after pulse labelling of the shoots with ¹⁴CO₂) suggesting an increased phloem unloading. It is argued that this leads to the measured increase in IAA activity (Radio Immuno Assay) in the zone of NO₃ supply. Beginning at the fifth day we observed a stimulation of cell division rate (incorporation of ³H-methylthymidine), accompanied by an increase in length of first order lateral roots.