Wheat Nutrient Research Articles

Soil fertility status and wheat nutrient content in Vertisol cropping systems of central highlands of Ethiopia

Land degradation reduces agricultural productivity and poses a serious threat on food security status of households. In Ethiopia, farmers have been using only urea and di-ammonium phosphate for more than 15 years. Several reports that indicate lack of response to these fertilizers, which could be due to limitation of nutrients other than nitrogen and phosphorus. Therefore, the present study was initiated to evaluate the soil fertility status of ten sites in central highlands Vertisols of Ethiopia and wheat nutrient content. The physico-chemical properties of soils showed that the soils were clayey in texture, neutral to slightly alkaline (pH 7.2–7.9) and low to medium in their organic matter (1.6–3.2 %) content. Total N content was low in 100 % of the samples while 80 % of the soil samples showed P deficiency ( 0.5 mg kg−1), Fe (>5 mg kg−1), and Mn (>1 mg kg−1) contents. However, 70 % of the samples were deficient in Zn ( 0.90) between soil and plant nutrient content was observed for P, K, Mg, Cu, Fe, Mn and Zn, implying that flag leaves at flowering stage can be used to calibrate soil and plant contents for the deficient nutrients.

Estimation of soil mechanical resistance parameter by using particle swarm optimization, genetic algorithm and multiple regression methods

Soil mechanical resistance directly affect seedling emergence and root growth. Tillage and irrigation managements decrease soil mechanical resistance in soil depth and increase root density in rhizosphere, wheat nutrient uptake and the yield. Soil mechanical resistance is high in the site of experiment due to high soil specific surface and cohesion between primary particles. Bulk density, pore size distribution and volumetric soil water content are important soil physical properties in relation to crop production through their effect on mechanical resistance. Determination of mechanical resistance in soils is difficult using penetrometer in fine textured soils particularly in hot and dry season. This study explores potentials of particle swarm optimization (PSO), genetic algorithm (GA) and multiple regression (MR) in the estimation of mechanical resistance value of soils. This research was carried out in a 3000m2 piece of land at Gorgan University of Agricultural Science and Natural Resource Research Farm, Grogan, Iran. The land was ploughed with five tillage methods, namely conventional tillage with moldboard ploughing (MT), rototiller (RT), double disc (DD), chisel plow (CP) and no-tillage (NT). Then bulk density, volumetric soil water content and soil mechanical resistance were measured at six stages during growing season of wheat. Two physical properties of soils that include the soil bulk density (BD) and volumetric soil water content (Өv) were presented to the models as independent parameters to estimate soil mechanical resistance (Es). The performance of models was comprehensively evaluated some statistical criteria. The results showed that among the various tillage methods, Moldboard tillage (MT) reduced soil mechanical resistance which increased plant's root growth, water and nutrient uptake, head number per square meter, and wheat yield. Also, the results revealed that PSO and GA models are promising approach for the estimation of soil mechanical resistance in compare with MR model. The results also show that PSO model can estimate soil mechanical resistance more accurate than GA and MR with R2=0.932 and RMSE=0.301.

Phosphorus amendment decreased cadmium (Cd) uptake and ameliorates chlorophyll contents, gas exchange attributes, antioxidants, and mineral nutrients in wheat (Triticum aestivum L.) under Cd stress

A 28-day pot (sand culture) experiment was carried to evaluate the effects of phosphorus (P) application in alleviating Cd phytotoxicity in wheat plants. Different levels of P (0, 10, and 20 kg ha−1) were applied without and with 100 µM Cd. The results showed that 100 µM Cd concentration decreased plant biomass, chlorophyll contents, gas exchange attributes, and mineral nutrients in wheat plants. Cadmium stress increased tissue Cd and H2O2 concentrations. The activities of superoxide dismutases (SOD), peroxidase (POD) enzymes, increased while the activities of catalase (CAT), ascorbic acid (AsA), α-tocopherol, and phenolics decreased under Cd stress. Phosphorus supply increased shoot biomass, leaf area, photosynthetic pigments, and mineral nutrients and decreased Cd and H2O2 concentrations in shoots. Phosphorus application improved antioxidant enzyme activities and gas exchange attributes which emerged as an important mechanism of Cd tolerance in wheat. We conclude that P application contributes to decreased Cd concentrations in wheat shoots and increased gas exchange attributes and antioxidant enzymes and could be implemented in a general scheme aiming at controlling Cd concentrations in wheat for sustained production of this important grain crop.

秸秆及秸秆黑炭对小麦养分吸收及棕壤酶活性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 秸秆及秸秆黑炭对小麦养分吸收及棕壤酶活性的影响 DOI: 10.5846/stxb201312313071 作者: 作者单位: 山东农业大学资源与环境学院,山东农业大学资源与环境学院 作者简介: 通讯作者: 中图分类号: S181; S154.2 基金项目: 国家"十二五"科技支撑计划(2011BAD11B01, 2011BAD11B02); 国家"948"重点项目(2011-G30); 山东省自主创新成果转化重大专项(2012ZHZX1A0408) Effects of straw and straw biochar on wheat nutrient uptake and enzyme activity in brown soil Author: Affiliation: College of Resources and Environment,Shandong Agricultural University,College of Resources and Environment,Shandong Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:通过小麦盆栽试验,研究了玉米秸秆及其秸秆黑炭施加对小麦养分吸收利用和棕壤酶活性的影响。试验设对照(CK),黑炭(B),秸秆还田(S),尿素(U),尿素+黑炭(UB)及尿素+秸秆还田(US)6个处理,各处理3次重复。结果表明:无氮肥施入下,B处理较CK和S处理籽粒产量显著提高99.4%和77.7%,小麦地上部氮、磷、钾吸收累积量分别显著提高94.1%-140.9%,55.4%-66.3%和53.1%-72.6%;有氮肥施入下,UB和US处理较U处理提高籽粒产量8.2%-8.8%,小麦地上部氮、磷、钾吸收累积量分别显著提高14.3%-27.8%,19.6%-30.9%和24.4%-40.9%。秸秆及秸秆黑炭施加处理的氮素利用率显著提高21.4%-41.7%。黑炭施加显著提高土壤中有机碳、NH4+-N、NO3--N和速效钾含量;在施氮条件下,秸秆还田显著提高土壤中NO3--N含量;秸秆及黑炭施加对有效磷含量无显著影响。秸秆还田显著提高了土壤脱氢酶、过氧化氢酶、脲酶和中性磷酸酶活性;施加黑炭也明显提高了土壤脱氢酶和脲酶活性,但抑制过氧化氢酶和中性磷酸酶活性。土壤脲酶活性与土壤有机碳、无机氮含量呈显著正相关,表明土壤酶可反映土壤肥力水平。 Abstract:Biochar made from crops straw is widely used as a great soil ameliorant that improves soil properties, protects soil environment, and enhances wheat growth. In this study, a potted wheat experiment was conducted to study the effects of corn straw and corn straw biochar on wheat nutrient uptake and utilization, yield, and enzyme activities in brown soil. Six treatments were set up with three replications as follows: control (CK), biochar (B), straw (S), urea (U), Urea+biochar (UB), and Urea+straw (US). In this study, the biochar was made from corn straw at 500 ℃ under anaerobic conditions. The results demonstrated that compared with the treatments of CK and S, the yield of B treatment was significantly increased by 99.4% and 77.7%, and the amount of accumulated N, phosphorus (P), and potassium (K) in the wheat aboveground biomass significantly increased by 94.1%-140.9%, 55.4%-66.3%, and 53.1%-72.6%, respectively. However, application of N fertilizer significantly increased the yield of UB and US treatments by 8.2%-8.8% and the amount of accumulated N, P, and K in wheat aboveground biomass increased by 14.3%-27.8%, 19.6%-30.9%, and 24.4%-40.9%, respectively, compared with the treatment of U. The efficiency of N use in treatments of UB and US increased by 21.4%-41.7% compared with the treatment of U; however, the enhancement of N use efficiency was higher in US than in UB. Biochar application significantly increased the content of organic carbon (C), NH4+-N, NO3--N, and available K in soil. Only does soil NO3--N content have significantly increased in straw incorporation. In the mature stage of wheat, the organic C content in the soil under the treatments of B and UB increased by 34.9%-54.2% in comparison with other treatments without biochar application. Meanwhile, there was no significant difference in soil organic C content under the treatment with straw. In this stage, NH4+-N content in soil of UB treatment was also increased by 10.9%-23.5%, which was higher than in other treatments. From heading stage to maize stage, compared with the treatments of US and U, NO3--N content of UB treatment increased by 30.9%-85.3% and 67.5%-126.7%, respectively. From seedling stage to mature stage, the available K content in soil of UB treatment increased by 23.3%-86.0% in comparison with US treatment. Nevertheless, there was no pronounced effect of biochar and straw on the available P content in soil. Moreover, straw incorporation significantly improved soil dehydrogenase, catalase, urease, and neutral phosphatase activities. Biochar application significantly enhanced soil dehydrogenase and urease activities, but it inhibited soil catalase and neutral phosphatase activities. The positive correlation between soil urease and organic C and inorganic N indicated that soil enzymes reflected the soil fertility level. In conclusion, a long term in-situ study is of great importance to investigate the long-term effects of straw incorporation and biochar on soil properties and yield of crops. 参考文献 相似文献 引证文献

Structural development of wheat nutrient transfer tissues and their relationships with filial tissues development.

Nutrients from spikelet phloem are commonly delivered to endosperm via caryopsis nutrient transfer tissues (NTTs). Elucidation of NTTs development is paramount to developing an understanding of the control of assimilate partitioning. Little information was available on the structural development of the entire NTTs and their functions, particularly those involved in the relationship between development of NTTs and growth of filial tissues including endosperm and embryo. In this study, wheat caryopses at different development stages were collected for observation of the NTTs by light microscopy, stereoscopic microscopy, and scanning electron microscopy. The cytological features of NTTs in the developing wheat caryopsis were clearly elucidated. The results were as follows: NTTs in the wheat caryopsis include maternal transfer tissues that are composed of vascular bundle, chalaza and nucellar projection transfer cells, and endosperm transfer tissues that consist of the aleurone transfer cells, starchy endosperm transfer cells, and endosperm conducting cells. The initiation, development, and apoptosis of these NTTs revealed the pattern of temporal and spatial gradient and were closely coordinated with endosperm and embryo development. These results may give us a further understanding about the functions of NTTs and their relationships with endosperm and embryo development.

Genotypic differences in utilization of nutrients in wheat under ambient ozone concentrations: Growth, biomass and yield

The effects of ambient ozone (O3) on wheat (Triticum aestivum L.) varieties HUW 510 and LOK-1 were studied at recommended and 1.5 times recommended NPK under natural field conditions using open top chambers under varying NPK levels. Ambient O3 was filtered out from air through charcoal filters for control plants (FCs), while non-filtered chambers received ambient O3 (NFCs). Twelve hourly mean concentrations of O3 varied from 10.3 to 110ppb. Plants growing in FCs showed better growth performance and higher biomass accumulation compared to those in NFCs at both NPK levels. There were improvements in yield and its quality parameters in FCs compared to NFCs at both NPK levels with no significant difference in yield between FCs and NFCs at 1.5 times recommended NPK in LOK-1 and at RNPK in HUW 510. Nitrogen utilization efficiency increased in NFCs compared to FCs in both the varieties, but lower capability of N acquisition under ambient O3 led to higher magnitude of reduction in yield of LOK-1 compared to HUW 510 at recommended NPK. The results clearly showed that 1.5 times recommended NPK alleviated the negative effects of ambient O3 pollutant in LOK-1 variety whereas recommended NPK in HUW 510.

Effect of Potassium Sulphate on the Growth and Uptake of Nutrients in Wheat (Triticum aestivum L.) Under Salt Stressed Conditions

Wheat is cultivated throughout the world to meet the needs of food and feed and industrial raw material in several countries. The salinity has been confirmed as main constrain of crop production and major threat to the agriculture. There is a need to increase the wheat production in marginalized soils. Different strategies have been adopted to increase the crop productivity in the world. During the current study effect of potassium sulphate was investigated for crop production in the salt stressed areas. Different application rate of K2SO4 (i. e., 50, 100, 150, 200 mM) under 150mM NaCl stress were used. It has been observed that the application of K2SO4 has increased the biomass production irrespective of the rate of application. The application of 200 mM K2SO4 proved to be the best to increase the maximum biomass in saline environment. It was also observed that the use of fertilizer has also increased the uptake of essential nutrients like potassium, calcium, magnesium and phosphorus in saline soils.

Effects of Mineral Nitrogen and Phosphorus Fertilizers on Yield and Nutrient Utilization of Bread Wheat (Tritcum aestivum) on the Sandy Soils of Hawzen District, Northern Ethiopia

On-farm field experiments were conducted to assess the effects of nitrogen (N) and phosphorus (P) on yield, yield components, nutrients uptake and use efficiencies, protein content of bread wheat, residual soil nitrogen and phosphorus availability and economic return of fertilizer application. The locations of the experiments were in two nearby farmers' field at Hawzen district, Northern Ethiopia. Factorial combinations of five N levels (0, 46, 69, 92 and 138 kg N/ha) and four levels of P (0, 46, 69 and 92 kg P2O5/ha) were laid out in a randomized complete block design with three replications. Experimental Field 1 was relatively better in its soil fertility than experimental Field 2 especially in its phosphorus availability and cation exchange capacity (CEC). However, both fields were low in their total soil nitrogen content. Grain yield of wheat significantly increased by 46% and 15% in Field 1 and Field 2, respectively at nitrogen application rate of 46 kg N/ha than the control. Nitrogen fertilization increased straw yield significantly only in experimental Field 1. Phosphorus application at a rate of 46 kg P2O5/ha increased significantly grain and straw yields by 38 % and 46 %, respectively in Field 2 than control. It is also economical to apply phosphorus at this rate for such farmers’ field because the grain yield marginal rate of return was 179 %. Consistent results were observed on wheat nutrient uptakes and nutrient use efficiencies. Grain and straw yields of wheat were not significantly affected by the main effect of phosphorus application in Field 1. These results are consistent with the soil analysis result before planting where the soil phosphorus was found to be low in Field 1 and very low in Field 2. Previous management by the farmers may have influenced the soil fertility status. There were no interaction effects of nitrogen and phosphorus to affect wheat productivity and nutrient utilization in both fields. Future approach to soil fertility management should consider the past management history and should also be site specific based on soil fertility assessment. As a result, a combined application of 46 kg N/ha and 46 kg P2O5/ha are recommended to achieve sustainable bread wheat production on the sandy soils of Hawzen district. But in fields with higher initial soil phosphorus level, there is no need of applying phosphate fertilizer.

Response of Wheat (Triticum aestivum) to Exogenously Applied Chromium: Effect on Growth, Chlorophyll and Mineral Composition

Heavy metals are very dangerous to environment and harm to all living organisms e.g. plants and animals etc. They enter the plant through soil and damage the internal mechanisms of plants. Chromium is very toxic to plants as well as animals. It has negative influences on plant growth, mineral nutrients and chlorophyll contents. Increasing its concentration causes reduction in plant growth, Chlorophyll contents and mineral nutrients in Wheat (Triticum aestivum L.). All the parameters were found to be reduced if there is increase in the concentration of chromium.

Potassium (K) effects and QTL mapping for K efficiency traits at seedling and adult stages in wheat

Potassium (K) is one of the most important mineral nutrients limiting plant growth in agricultural systems. This study investigated the effects of low-K treatments and detected quantitative trait loci (QTLs) for K efficiency traits at the seedling and adult stages of wheat. Eleven seedling traits under a hydroponic culture trial with five K treatments and nine adult traits in a pot trial and a field trial with three K treatments were investigated using a set of wheat recombinant inbred lines (RILs). Values of most of the seedling and adult traits decreased with decreasing K supply, but the K-use efficiency and ratio of dry weight between seedling roots and shoots (RSDW) increased. A total of 87 QTLs for seedling traits in the hydroponic culture trial and 51 and 29 QTLs for adult traits in the pot and field trials, respectively, were detected. We also identified 15 relatively high-frequency QTLs (RHF-QTLs) which can be detected in over half of the treatments and 21 QTL clusters which is defined as the co-location of QTLs for more than two traits. K efficiency traits and the related QTLs of wheat were greatly affected by K treatments. Several relatively stable QTLs and important QTL clusters may be potential targets for marker-assisted selection for wheat nutrient efficiency.

Vermicompost effects on wheat yield and nutrient contents in soil and plant

Vermicomposting of organic waste can play an important role in integrated waste management strategies. Ability of the earthworm Eisenia foetida to transform anaerobically digested sewage sludge (SS) amended with hazelnut husk (HH) and cow manure (CM) in different proportions (0% SS + 50% HH + 50% CM; 10% SS + 45% HH + 45% CM; 20% SS + 40% HH + 40% CM; 30% SS + 35% HH + 35% CM; 40 SS% + 30% HH + 30% CM; 50% SS + 25% HH + 25% CM) was studied in a greenhouse experiment in terms of the effects of vermicompost on wheat (Triticum aestium) yield and nutrient content in soil and plant. All vermicomposted and non- vermicomposted mixtures exhibited positive effect on the yield and nutrient concentrations of wheat compared to the control pots. The vermicomposted organic waste mixtures showed comparatively better effect on plant production than the non- vermicomposted organic waste mixtures. Vermicomposted 50% SS + 25% HH + 25% CM mixtures showed the highest positive effect on yield compared to the other treatments.

Content of selected nutrients in wheat, barley and oat grain from organic and conventional farming

Content of selected nutrients in wheat, barley and oat grain from organic and conventional farming

Role of soil enzymes produced by PGPR strains in wheat growth and nutrient uptake parameters in the filed conditions

Role of soil enzymes produced by PGPR strains in wheat growth and nutrient uptake parameters in the filed conditions

Major quantitative trait loci for seminal root morphology of wheat seedlings

Vigorous early root growth at seedling stage has been shown to be important for efficient acquisition of nutrients in wheat (Triticum aestivum L.). Identifying quantitative trait loci (QTL) for early root growth can facilitate the selection of wheat varieties with efficient nutrient use. A recombinant inbred line population derived from two Chinese wheat varieties, Xiaoyan 54 and Jing 411, was grown hydroponically at seedling stage. The maximum root length (MRL), primary root length (PRL), lateral root length (LRL), total root length (TRL), and root tip number (RN) of seminal roots were measured using the WinRHIZO Root Analyser. Numerous QTL for the investigated root traits were detected with QTL numbers varying from two to six, depending on the traits. Among them, two loci had major effects on primary (MRL and PRL) and lateral (LRL and RN) root parameters, respectively. The QTL (namely qTaLRO-B1) between Xgwm210 and Xbarc1138.2 on chromosome 2B explained 68.0 and 59.0% of phenotypic variations in MRL and PRL, respectively; the major QTL between Xgwm570 and Xgwm169.2 on chromosome 6A explained 30.5 and 24.5% of phenotypic variations in LRL and RN, respectively. These two major loci showed linkage with previous reported QTL for yield component and nutrient uptake. Detailed analysis of qTaLRO-B1 indicated that the positive allele of qTaLRO-B1 showed dominance over the negative allele, which showed impairment in primary root elongation. The existence of major QTL for root trait and their linkage with agronomic traits and nutrient uptake will facilitate the design of root morphology for better yield performance and efficient nutrient use.

Uptake and use efficiency of N, P, K, Ca and Al by Al-sensitive and Al-tolerant cultivars of wheat under a wide range of soil Al concentrations

The impacts of acidic soils and Al toxicity on wheat nutrient economy have been scarcely researched under field conditions even though these soils are widely spread in wheat production areas around the world. The main objective of this study was to quantitatively evaluate the element (N, P, K, Ca and Al) economy of an Al-sensitive and an Al-tolerant wheat cultivar growing under different soil Al concentrations at field conditions. To reach this objective, two field experiments were conducted in an Andisol in Valdivia (39°47′18″S, 73°14′05″W), Chile. Treatments were a factorial arrangement of: (i) two spring wheat cultivars (Al-sensitive, Domo.INIA and Al-tolerant, Dalcahue.INIA) and (ii) five exchangeable Al levels (0–2.7 cmol (+) kg −1) with three replicates. At harvest, plant biomass was sampled and divided into 5 organ categories: ears, grains, blade leaves, stems plus sheath leaves and roots. The element content (N, P, K, Ca and Al) in each organ was measured to quantify element uptake and concentration, nutrient uptake efficiency (UPE) and nutrient utilization efficiency (UTE). Element uptake (N, P, K, Ca, and Al) was negatively affected by the increased soil Al concentration in above-ground and root biomass in both cultivars ( R 2 = 0.61–0.98, p < 0.01), although clear differences were found between cultivars. On the contrary, the impact of soil exchangeable Al on the plant element concentration was minor, showing weak associations with soil Al levels. However, the Al concentration in above-ground tissues of the Al-sensitive cultivar was an exception because it increased exponentially with the Al soil concentration ( R 2 = 0.96–0.99, p < 0.001). Nutrient uptake efficiencies, UPEs (N, P, K and Ca), were negatively affected by soil Al concentrations and were well described by linear equations in both cultivars ( R 2 = 0.58–0.98, p < 0.05), with notable differences between them. Both nutrient uptake (capture) and UPE were the traits that best explained above-ground biomass production ( R 2 = 0.82–0.99, p < 0.001, n = 20). Nutrient utilization efficiency, UTEs (N, P, K and Ca) responded more conservatively to the soil Al concentration, except for the Al sensitive cultivar under very high soil Al levels.

Effects of Nitrogen and Phosphorus Application from Swine Manure on Winter Wheat Growth and Nutrient Utilization

Two trials were conducted to determine the effect of swine manure application on wheat growth and nutrient uptake. Manure was added to soil on a nitrogen (N) basis at 325 kg plant-available nitrogen (PAN) ha−1 (experiment 1) and on a phosphorus (P) basis at 50 kg P ha−1, while maintaining a rate of 325 kg PAN ha−1 through ammonium sulfate addition (experiment 2). Manure treatments increased overall wheat growth by 29% (P < 0.005) compared to the negative control (NC) and increased plant tissue N mass 48% (P < 0.001) and P mass 61% (P < 0.002) (experiment 1). Fertilizer control tended to increase (P < 0.10) wheat growth and increased total vegetative tissue N mass by 23% (P < 0.006) and potassium mass by 20% (P < 0.002) compared to manure treatments. Manure treatments increased wheat growth by 23% (P < 0.03) compared to the NC at the first harvest (experiment 2).

Pseudomonas bacteria and phosphorous fertilization, affecting wheat (Triticum aestivum L.) yield and P uptake under greenhouse and field conditions

We have recently indicated the plant growth promoting activities of Pseudomonas sp. as well as their alleviating effects on some soil stressors such as salinity. This is because in recent years, biological fertilizers have received special attention by scientists in sustainable agriculture. Accordingly, it is pertinent to specify the beneficiary level of such soil bacteria on plant growth including phosphorous (P) uptake. Hence, the objectives were to determine: (1) the plant growth promoting effects of the tested Pseudomonas sp., and (2) its combined effects with different P fertilization rates on the nutrient uptake (N, P, and K) and yield of wheat (Triticumaestivum L.) under greenhouse and field conditions. The experiments were factorially arranged on the basis of a completely randomized block design with three replicates and were conducted at the Research Farm of Agriculture and Natural Resources Research Center of Khorasan, Mashhad, Iran. P was fertilized at three levels including 0, 25 and 50 kg/ha P2O5. Pseudomonas sp. including Pseudomonasfluorescens 153, P. fluorescens 169, P.putida 4, and P.putida 108 were tested. Activities such as production of ACC deaminase and IAA-like products, as well as P solubilization were among the most important activities of the tested Pseudomonas sp. Such bacterial effects greatly enhanced wheat growth and yield under greenhouse and field conditions. The results also showed that the effects of Pseudomonas sp. on wheat nutrient uptake and the effects of bacteria as well as P fertilization on wheat yield were significant. P.putida 108 was the most effective strain enhancing wheat P uptake and grain yield under greenhouse (96 and 58%) and field (80 and 37%) conditions, respectively. Hence, although Pseudomonas sp. could be a suitable replacement for high P fertilization, however, the optimum wheat yield resulted when the bioinoculants are combined with 50% (25 kg/ha P2O5) P fertilization. This finding has great agricultural and environmental implications.

Effects of biosolids from tomato processing on soil fertility and wheat growth in a Greek alfisol

AbstractThe effects of biosolids from tomato processing on soil properties and wheat growth were investigated in an Alfisol from central Greece. Biosolids were mixed with soil from the surface (Ap) or subsurface (Bt) horizon in plastic containers at rates of 1%, 5%, and 10% by dry weight (d.w.; equivalent to 10, 50, and 100 Mg ha–1). Biosolid treatments were compared to an NH4Cl application (50 mg N kg–1) and an untreated control in (1) a 102 d incubation experiment at 28°C to determine biosolid nitrification potential and (2) a 45 d outdoor experiment to evaluate effects on soil fertility and wheat growth. Mineralization of biosolids in the incubation experiment resulted in accumulation of nitrate‐N and indicated that biosolids were able to supply N that was in excess of crop needs in treatments of 5% and 10%. After 45 d of wheat growth, available soil nutrients (N, P) and P uptake by wheat were distinctly lower in the Bt than in the Ap horizon. However, soil pH, electrical conductivity, organic matter, total N, nitrate‐N, extractable P, and exchangeable K increased with increasing rate of biosolid application in both soils. These were followed by corresponding increases in wheat nutrient uptake and biomass production, thus demonstrating the importance of this organic material for sustaining production in soils of low immediate fertility. Compared to the NH4Cl treatment (50 kg N ha–1 equivalent), biosolid application rates of 5% and 10% had higher available soil nutrients, similar or higher nutrient uptake and higher wheat biomass. But only an application of 10% biosolids provided sufficient N levels for wheat in the surface soil, and even higher applications were required for providing sufficient N and P in the Bt horizon.

Nutrients in wheat, flour, and bread.

Nutrients in wheat, flour, and bread.

Effects of arbuscular mycorrhiza, soil sterilization, and soil compaction on wheat ( Triticum aestivum L.) nutrients uptake

The stress of soil compaction, because of using agricultural machinery, may provide conditions such as limiting nutrient uptake, not suitable for plant growth. Here we hypothesized that using arbuscular mycorrhiza (AM, plant symbiotic fungi), as a biological method, may overcome the stress of soil compaction on wheat ( Triticum aestivum L.) growth by enhancing nutrient uptake. Soil surface layer of the Experimental Research Field of Soil and Water Research Institute in Karaj, Iran, was sieved, sterilized, and compacted at 10 kg pots in two experiments. At seeding wheat seeds were inoculated with different species of Glomus fungi with different origins. Shoot nutrient uptake of N, P, K, Fe, Mn, Zn, Cu was determined. Soil sterilization significantly increased the nutrient uptake of mycorrhizal wheat even at the highest level of compaction. Even under compacted conditions, increased P uptake, due to AM inoculation had an important role to alleviate the stress. This novel finding may indicate the important role of AM to overcome the stress of soil compaction on wheat nutrient uptake, the independency of AM origin on their functionality, and the great importance of managing soil biological communities in agricultural systems.