Evaluation of p as a limiting macronutrient in volcanic ash soils of guatemala

Abstract

P status of soils derived from volcanic ash in Guatemala was investigated. Growth chamber and greenhouse studies were conducted with H‐3 hybrid corn (Zea mays). All plants exhibited P deficiency symptoms and yielded less dry matter when they were grown on soils that received only lime at a rate equivalent to 2,240 and 4,480 kg/ha. The P content of plants was low and correlated with P deficiency symptoms. Application of P (336 and 672 kg/ha) under constant liming corrected the P deficiencies and increased dry matter. In comparative studies, plants grown on a highly fertile, non‐volcanic soil showed vigorous growth and yielded high dry matter. Apparently, P was limiting productivity in volcanic ash soils of Guatemala, and due to low exchangeable Al, addition of only lime did not produce beneficial results. The soils responded to P fertilization and they should be supplied large quantities of this macronutrient.     

The determination of ‘L’ values by discrete and integrated sampling procedures

Abstract

A discrete and an integrated sampling procedure were used to determine ‘ L ‘ values for maize plants grown in a soil. In the discrete procedure a plant was grown in a sand culture labelled with ³³P solution and then transferred in a soil which was labelled with ³²P. In the integrated sampling procedure plants were grown entirely in a P label led soil.

The discrete procedure permits point of time observation so that changes in the equilibrium between solution and surface P and mineralization rates can be monitored.     

Plant availability of isotopically exchangeable and isotopically nonexchangeable phosphate in soils

Isotopically exchangeable P (IEP) is usually considered to be completely plant‐available and the major source of P for plant uptake. The aim of the present study is to test whether plants can, besides IEP, also use non‐IEP and if part of the IEP has an equilibrium concentration in soil solution which is below the minimum concentration, C_Lmin, and can therefore not be taken up by plants. A pot experiment was carried out with maize for two years on two soils, an acid sandy and a neutral loamy soil, either without P fertilizer or fertilized with ten P sources of different solubility. Throughout both years of the study, pots were kept moist either without plants or planted twice with maize (Zea mays L., cv. Athletico). At the end of the experiment, plant P uptake, P concentration in the soil solution (C_L), and P accessible to isotopic exchange within 5 d (E_5d) were measured. Plant growth decreased the E_5d which was about equal to P uptake by maize for most treatments in the acid soil. But for some treatments, i.e., five in the acid and eight in the neutral soil, P uptake was up to 50% larger than the decrease of E_5d, indicating that plants had, besides IEP, also used P from non‐IEP sources. At adequate P supply, both soils had an E_5d of about 100 mg P (kg soil)^–1, but about 30 to 40 mg kg^–1 of this IEP had an equilibrium P concentration in the soil solution below C_Lmin of 0.1 μmol L^–1 at which P would actually not be plant‐available. This study shows that plants take up P mainly from IEP, but not the whole IEP is plant‐available. Furthermore, plants may also use P from non‐IEP sources.     

Effect of one phosphorus rate placed in different soil volumes on p uptake and growth of wheat

Abstract

The volume of soil treated with P fertilizer affects P uptake by the crop. Earlier studies have shown that the stimulation of root growth in P‐fertilized soil was similar for both corn (Zea mays L.) and soybean (Glycine max L. Merr). The objective of this research was to determine the effect of fertilizer P placement on P uptake and shoot and root growth of spring wheat (Triticum vulgare L.). Wheat was grown for 34 days in Raub silt loam (Aquic Argiudolls) in a controlled climate chamber. One rate of phosphate per pot, 150 mg P per three kg of soil, was mixed with 2, 5, 10, 20, 40 and 100% of the soil in the pot. The P was equilibrated with moist soil for 5 days at 70°C followed by 21 days at 25° C before transplanting 8‐day‐old wheat plants into each 3 L pot. The P stimulation of root growth in the P‐treated soil was similar to that for corn and soybeans. The effect could be described by the equation y = x^0.7 where y is the fraction of the root system in the P‐fertilized soil where P is mixed with x fraction of the soil. The greatest P uptake and plant growth occurred when added P was mixed with 20% of the soil.     

Iron‐reducing bacteria can enhance the activation and turnover of the Fe(III)‐fixed phosphorus for mycorrhizal plants

In a greenhouse experiment, Medicago sativa was grown in iron‐rich soil colonized with iron‐reducing bacteria (IRB) and/or Glomus mosseae (GM) under different inorganic phosphorus levels, which was to understand the effects of IRB and GM on the activation and turnover of the Fe(III)‐fixed phosphorus. The results showed that at the both P rates, dual‐inoculation treatment stimulated the hyphal growth and increased the shoot P content. IRB could accelerate mycorrhizal colonization, and showed a positive effect on plant biomass and P uptake at both P levels. Compared to sole‐IRB or GM treatment, the dual inoculation treatment increased the soil available P content at both P rates (p < 0.05), which was in the following order: the dual IRB+GM > the sole IRB > the sole GM > control for soil SMP content at low P rate, whilst the dual IRB+GM > the sole IRB ≈ the sole GM > control treatment at high P rate. Compared with the IRB treatment, the GM treatment significantly decreased the soil available P content and the MBP content at low P rate, but made no difference at high P rates. The soil MBC in dual‐inoculation treatment was greatest under the high P level, while the highest soil MBC was the sole‐GM treatment under the low P level. The sole GM treatment showed significantly (p < 0.05) higher soil MBC than that of sole IRB at low P rate (p < 0.05), while there was no significant differences between sole IRB and sole GM at high P rate. Our results suggested that the interaction between GM and IRB had synergetic effect on the mobilization of Fe(III)‐fixed P and their relationship could be regulated by the turnover of MBP. The fact that plants acquired more P via mycorrhizal pathway in the GM‐IRB system suggested that the three symbiont of plant‐GM‐IRB had great ecological and functional significance for P activity in tropical and subtropical soil.     

Phosphorus Uptake from Green Manures and Phosphate Fertilizers Applied in an Acid Tropical Soil

Abstract

Quantifying the relative contribution of different phosphorus (P) sources to P uptake can lead to greater understanding of the mechanisms that increase available P in integrated P management systems. The ³²P–³³P double isotope labeling technique was used to determine the relative contribution of green manures (GMs) and P fertilizers to P uptake by Setaria grass (Setaria sphacelata) grown in an amended tropical acid soil (Bungor series) in a glasshouse study. The amendments were factorial combinations of GMs (Calopogonium caeruleum, Gliricidia sepium and Imperata cylindrica) and P fertilizers [phosphate rocks (PRs) from North Carolina (NCPR), China (CPR) and Algeria (APR), and triple superphosphate (TSP)]. Dry matter yield, P uptake, and P utilization from the amendments were monitored at 4, 8, and 15 weeks after establishment (WAE). The GMs alone or in combination with P fertilizers contributed less than 5% to total P uptake in this soil, but total P uptake into Setaria plants in the GM treatments was three to four times that of the P fertilizers because the GMs mobilized more soil P. Also, the GMs markedly increased fertilizer P utilization in the combined treatments, from 3% to 39% with CPR, from 6–9% to 19–48% with reactive PRs, and from 6% to 37% with TSP in this soil. Both P_GM and the other decomposition products were probably involved in reducing soil P‐retention capacity. Mobilization of soil P was most likely the result of the action of the other decomposition products. These results demonstrate the high potential of integrating GMs and PRs for managing P in tropical soils and the importance of the soil P mobilization capacity of the organic components. Even the low‐quality Imperata GM enhanced the effectiveness of the reactive APR more than fourfold.     

Soil phosphorus availability to millet roots

Abstract

Soil solution P level is believed to be important in determining P uptake rates from soil. The objective of this research was to investigate the relation between initial P concentration in the soil solution and P flux into the root. Millet (Panicum milaceum) was grown on five soils each of which was adjusted to six C_li levels by addition of P. Millet was also grown in solution culture and P influx vs. P concentration in solution measured. There was a curvilinear relation between P influx and relative yield of the C_li levels on each soil (R²=0.74). A P influx of at least 16 pmoles cm^‐1 sec^‐1 was needed to obtain 90% of maximum yield. However, yield response was not correlated with C_li, indicating C_li was not a suitable indicator of P availability on these soils. Influx of P on soils with C_li less than 6 μM was greater than occurred at similar P concentrations in solution culture indicating P influx was increased by the effect of the root on the soil.     

Improvement of wheat and maize crops by inoculating Aspergillus spp. in alkaline soil fertilized with rock phosphate

Aspergillus tubingensis and A. niger were isolated from the landfills of rock phosphate mines and tested for their efficacy to solubilize rock phosphate (RP), and improve plant growth and phosphate (P) uptake by plants grown in soil amended with RP. The results showed that they effectively solubilized RP in Pikovskaya's (PKV) liquid medium and released significantly higher amounts of P into the medium. A. tubingensis solubilized and released 380.8 μg P mL^?1, A. niger showed better efficiency and produced 403.8 μg P mL^?1. Field experiments with two consecutive crops in alkaline agricultural soil showed that inoculation of these fungi along with RP fertilization significantly increased yield and nutrient uptake of wheat and maize plants compared with control soil. P uptake by wheat and maize plants and the available P increased significantly in the RP-amended soil inoculated with fungi compared with control. These results suggest that the fertilizer value of RP can be increased, especially in alkaline soils, by inoculating P-solubilizing fungi.     

Phosphorus nutrition of white lupine grown on a Calciaquoll

Abstract

White lupine (Lupinus albus L.) and navy bean (Phaseolus vulgaris L.) are legumes with and without the proteoid root characteristic, respectively. The influence of P (0, 40, 80, and 120 mg/kg of NaH₂PO₄‐P) and source of nitrogen (N) [inoculation with Bradyrhizobium lupini or Rhizobium phaseoli vs. NH₄NO₃] on phosphorus (P) uptake by navy bean and white lupine grown on a Calciaquoll low in available P and N was studied under greenhouse conditions. Both species responded to P fertilizer, but P accumulation in navy bean tops was much greater than in white lupine. Inoculated white lupine plants accumulated more P than their NH₄NO₃‐treated counterparts. Growth and P uptake of 17‐day‐old flax (Linum usitatissium L.) plants grown in pots previously planted to white lupine, but not in their navy bean counterparts, was severely retarded. White lupine did not enhance the availability of soil P in the calcareous soil.     

Phosphorus source,organic matter,and arbuscular mycorrhiza effects on growth and mineral acquisition of chickpea grown in acidic soil

Abstract

Plants grown in acidic soil usually require relatively high amounts of available phosphorus (P) to optimize growth and productivity, and sources of available P are often added to meet these requirements. Phosphorus may also be made available at relatively high rates in native soil when roots are colonized with arbuscular mycorrhizal fungi (AMF). Addition of P to soil usually reduces root‐AMF colonization and decreases beneficial effects ofAMF to plants. In glasshouse experiments, soil treatments of P [0 P (Control), 50 mg soluble‐P kg^?1 as KH₂PO₄ (SP), and 200 mg P kg^?1 as phosphate rock (PR)], organic matter (OM) at 12.5 g kg^?1, AMF (Glomus darum), and various combinations of these (OM+SP, OM+PR, AMF+SP, AMF+PR, AMF+OM, AMF+OM+SP, and AMF+OM+PR) were added to steam treated acidic Lily soil (Typic Hapludult, pH_w=5.8) to determine treatment effects on growth and mineral acquisition by chickpea (Cicer areitinum L.). The various treatment applications increased shoot dry matter (DM) above the Control, but not root DM. Percentage AMF‐root colonization increased 2‐fold or more when mycorrhizal plants were grown with AMF, OM+SP, and OM+PR. Regardless of P source, plant acquisition of P, sulfur (S), magnesium (Mg), calcium (Ca), and potassium (K) was enhanced compared to the Control, and mineral enhancement was greater in PR compared to SP plants. Mycorrhizal plants also had enhanced acquisition of macronutrients. OM+SP and OM+PR enhanced acquisition of P, K, and Mg, but not Ca. Concentrations of Fe, Mn, Cu, and Al were generally lower than Controls in SP, RP, AMF+PR, AMF+SP, and OM plants, and mycorrhizal plants especially had enhanced micronutrients. Relative agronomic effectiveness values for shoot DM and shoot P, Ca, and Mg contents were considerably higher for PR, including OM+PR, AMF+PR, and AMF+OM+PR, than for SP. PR and OM applications to AMF plants are low‐cost attractive and ecologically sound alternatives to intensive use of P fertilizers for crops grown in acidic soils.     

Effects of Stoichiometric Traits of Nitrogen and Phosphorus in Soil on Photosynthetic Characteristics of Wheat

ABSTRACT

To improve the use efficiency of fertilizer in agricultural production, effects of stoichiometric traits of soil available nitrogen (N) and phosphorus (P) on photosynthetic gas exchange parameters and fluorescence parameters of wheat were revealed in a full factorial pot experiment with our N and P fertilizer rates each. Results showed that at the same level of soil available N, the net photosynthetic rate (Pn), stomatal conductance (Cond), photochemical quenching (qP), the quantum yield of PSII photochemistry (ΦPSII), and apparent electron transport rate (ETR) of wheat generally increased with a decline of soil N/P ecological stoichiometric ratio (by increasing soil available P), whereas the intercellular CO₂ concentration (Ci) and nonphotochemical quenching (NPQ) of wheat decreased with a decline of soil N/P. At the same level of soil available P, Pn, Cond, qP, ΦPSII, and ETR of wheat initially increased and then decreased with an increase of soil N/P ecological stoichiometric ratio (by increasing soil available N), whereas the dynamics of Ci and NPQ of wheat were exactly opposite to those of the above parameters. A limiting effect of soil available P on the photosynthesis of wheat occurred during the entire experiment. It was deduced that the cultivated soil, with the available N of 258.4 mg·kg^?1, available P of 89.6 mg·kg^?1, and stoichiometric N/P of 2.88, was suitable for weak gluten wheat cultivar Yangmai15. Therefore, another approach to improves nutrient use efficiency was provided on the basis of ecological stoichiometry theory.     

Differential Access to Phosphorus Pools of an Oxisol by Mycorrhizal and Nonmycorrhizal Maize

Abstract

This study investigated whether arbuscular mycorrhizal fungi (AMF) could take up phosphorus (P) from pools that are normally considered unavailable to plants. An aluminum (Al) resistant maize variety, inoculated with three species of Glomus or uninoculated, supplied with nutrient solution without P, was cultivated (90 days) in the A and B horizons of a P‐fixing Oxisol. Plant uptake of P was calculated by assessing P content of shoots and roots and correcting for seed P. Soil P fractionation was done prior to and at the end of the experiment. Phosphorus in the A and B soil horizons (～270 mg soil kg^?1) was differently distributed among the pools. Nonmycorrhizal plants did not acquire any P from the soil, and all P found in the plants was from the seeds. Mycorrhizal plants depleted the inorganic Resin‐P and NaHCO₃‐P, used part of the inorganic NaOH‐P, and used neither the recalcitrant inorganic P nor the organic P fractions. Changes in plant P content matched changes in the soil P pools. Mechanisms by which maize through the mycorrhizal association acquires P are discussed. In the cultivar used, the mechanisms to cope with P deficiency and Al excess are different.     

Nutrient uptake and growth of potato: Arbuscular mycorrhiza symbiosis interacts with quality and quantity of amended biochars

Aims : The aim of this study was to explore interactive effects between quality (types) and quantity (application rates) of biochar as well as of arbuscular mycorrhiza (AM) symbiosis on the growth of potato plants. Methods : A low P sandy loam soil was amended with 0%, 1.5%, or 2.5% (w/w) of either of 4 types of biochar, which were produced from wheat straw pellets (WSP) or miscanthus straw pellets (MSP) pyrolyzed at temperatures of either 550°C or 700°C. Potato plants grown in pots containing the soils or soil biochar mixture were inoculated with or without AM fungus (AMF), Rhizophagus irregularis. The experiment was carried out under fully irrigated semi‐field conditions and plants were harvested 101 days after planting. Results : Application of high temperature biochar decreased growth, biomass and tuber yield of potato plants, while the low temperature biochar had a similar effect on yield as plants grown without biochar amendment. Total biomass of potato plants were decreased with the increasing rate of biochar. Arbuscular mycorrhizal fungus inoculation stimulated the growth of potato plants in all organs, increased tuber biomass significantly in 1.5% MSP700 amended plants, and to a lesser degree for WSP700, MSP550, and WSP550. In addition, plant biomass gain was linearly related to N, P, and K uptake, the ratio of P to N in the leaf of plants indicated that all treatments were mainly P‐limited. A multiple linear regression using P uptake and biochar rate as independent variables explained 91% of the variation in total biomass. The single effect of AMF inoculation, type and rate of biochar affected plant N, P and K uptake similarly. While AMF inoculation significantly increased P uptake in potato plants grown in soil with WSP700 or MSP700 despite of the rate of biochar. In general, application of biochar significantly increased AMF root colonization of potato plants. Conclusions : The application of MSP550 at 1.5% combined with AMF stimulated growth of potato the most. Furthermore, the results indicated that the interactive effect of AMF inoculation, biochar type and application rate on potato growth to a large extent could be explained by effects on plant nutrient uptake.     

Phosphorus Management of Lucerne Grown on Calcareous Soil in Turkey

ABSTRACT

Lucerne or alfalfa (Medicago sativa L.) is grown as a forage crop on many livestock farms. In calcareous soils in eastern Turkey, lucerne production requires phosphorus (P) additions as the soils are naturally P deficient. Phosphorus sorption isotherms were used to estimate P fertilizer needs for lucerne grown for two years in a 3-cut system on a calcareous P deficient Aridisol in eastern Anatolia, Erzurum province, Turkey. Annual P applications ranged from 0–1200 kg P ha^?1. The Langmuir two-surface adsorption equation was used to derive the maximum P sorption capacity of unamended soil and to determine soil solution P, maximum buffer capacity (MBC), equilibrium buffer capacity (EBC), and P saturation at the optimum economic P rate (OEPR) for dry matter (DM) production. Soils were tested for Olson P at the onset of the study and after two years of P applications. In both years, tissue was analyzed for P content at flowering prior to first cutting. The OEPR (2-year average) was 754 kg P ha^?1 yr^?1 corresponding with a soil solution P concentration of 0.30 mg L^?1, a DM yield of 8725 kg DM ha^?1, and $528 ha^?1 annual profit. The P content of leaves at flowering increased linearly with P application beyond 100 kg P ha^?1 and was 3.2 g kg^?1 P at the OEPR. The unfertilized soil had an EBC, MBC, P saturation, and X_max of 3304 mL g^?1, 3401 mL g^?1, 6%, and 1086 mL g^?1, respectively, whereas two years of fertilization to the OEPR decreased EBC and MBC to 358 mL g^?1 and 540 mL g^?1, and increased P saturation and Olsen P to 56% and 32 mg kg^?1, respectively. These results suggest a P saturation >50% or Olsen P >30 mg kg^?1 are needed to maintain an optimum soil solution concentration of 0.30 mg L^?1 in this calcareous Aridisol. Similar studies with different soils and initial soil test P levels are needed to conclude if these critical soil test values can be applied across the region.     

Assessing the Effect of Phosphorus Fertilizer Levels on Soil Phosphorus Fractionation in Rhizosphere and Non-Rhizosphere Soils of Wheat

This study evaluated the effects of phosphorus (P) fertilizer levels on inorganic P fractions. Wheat cultivars (Azadi and Marvdasht) were grown in the soils amended with the four rates of P fertilizer levels (no fertilizer, 10, 15, and 25 mg available P kg^?1 soil). Soils were sampled from rhizosphere and non-rhizosphere areas after 6 weeks. The mean of all P fractions was significantly different in various P fertilizer levels. The smallest and the largest amounts of all P fractions were observed in the soil with no P and in 25 mg kg^?1 soil P level, respectively. The Azadi cultivar, as P-efficient, showed the smallest increase in soil P fractions with increasing soil P levels. The means of all P fractions except Al-phosphates (Al-P) were significantly higher in non-rhizosphere soil. There were differences between these cultivars associated with the more inaccessible fractions at the 15 mg P kg^?1 soil level.     

Doybean growth and composition as affected by K,Ca, and Mg rates and corn rotation

Abstract

Different rates of K, Ca, and Mg were applied to bulklots of Decatur clay loam (pH 5.8) which had been collected from an area under natural vegetation. Nitrogen and P were each applied at the rate of 100 ppm. Soybean (Glycine max L.) and corn (Zea mays L.) were planted to pots in four replications of each treatment. Plants were grown for 6 weeks and subsequently all the pots were re‐planted to soybeans. This crop rotation was repeated until six crops had been harvested from each pot.

Potassium fertilization did not affect soybean growth but increased the dry matter of corn plants. Calcium application affected the growth of neither crop, but Mg addition to the soil reduced the growth of both crops. The composition of the plants generally reflected the available amounts of each nutrient. Additionally, Mg consistently decreased K in soybeans but increased Mn in the two crops. The inclusion of corn in rotation with soybeans resulted in the following effects on the succeeding soybean harvests: more tolerance to high Mg, greater reduction of plant Ca and Mg caused by K application, and lower levels of available K and Ma in soils and soybeans. However, the greater rate of depletion of soil K and Mn under corn rotation did not appear Co affect the dry matter yields of the following soybean plants relative to the plants under the continuous soybean cropping system.     

Available soil nutrients and water content affect leaf nutrient concentrations and stoichiometry at different ages of Leucaena leucocephala forests in dry-hot valley

Purpose

The carbon (C), nitrogen (N), and phosphorus (P) concentrations of leaves can reflect soil nutrient supply conditions and changes in soil. An understanding of species adaptability and nutrient use efficiency in extreme ecosystems can help land managers choose effective methods to improve management and community structure of introduced plants which may induce biological invasion and limit the regeneration of native species.

Materials and methods

We selected the Leucaena leucocephala forests in three ages (9, 15, and 26 years old) in the Jiangjiagou Gully to study the relationships between (i) soil factors and forest age and (ii) leaf nutrient concentrations. Soil factors and leaf nutrients were measured in nine sampling quadrats of 10?×?10 m of each plot. We used ANOVA to examine differences in leaf variables and soil factors at different ages of L. leucocephala forest. Pearson’s correlation analysis and linear regression analysis were conducted to identify the relationships between soil factors and leaf variables. Then, we used analysis of covariance to examine combined effects of forest ages and soil factors on leaf variables.

Results and discussion

Leaf N was significantly correlated with available P, while leaf P was significantly correlated with both available P and available N. Leaf N and P had no significant relationship with soil total N and P. Leaf C:N:P stoichiometries had a higher significant correlation with total N, available N, and soil water content.

Conclusions

Our findings illustrate that available N and available P are the main limitations for L. leucocephala, though available P imposed a stronger limitation than available N. Moreover, soil water content played an indispensable role on nutrient accumulation and the soil ecological environment. Our results provide useful information to improve L. leucocephala community structure and reduce soil degradation in a dry-hot valley.

     

Nutrient distribution around roots of Brachiaria,maize, sorghum,and upland rice in an Andisol

Plants grown on Andisols often have an insufficient phosphorus (P) supply, since active aluminium (AI) and iron bind P in low available forms to the plants. The objectives of the present studies were to examine the differences in growth associated with the P-uptake ability among four Gramineae, to determine which P-forms are utilised, and to relate plant growth to the distribution of nutrients in soil close to the roots. Rhizosphere soil was separated from bulk soil by using a rhizobox system. Shoot and root yields and nutrient contents of maize (Zea mays L.), Sorghum bicolor (L.), Brachiaria dictyoneura (Stapf), and upland rice (Oryza sativa L.) were determined after cultivation in rhizoboxes for 105 d. Soil was sampled at increasing distances from the roots and analysed for P compounds, other nutrients, and pH. Maize gave the highest yield by using P reserves in its large seeds, resulting in the greatest depletion of K in the root soil of maize. Brachiaria showed the highest efficiency while upland rice the lowest in using soil P, respectively. The amounts of Bray-2 P and acetic acid-extractable P were significantly lower in root soil compared to bulk soil. Soil pH increased in the root soil of all crops, mainly around the Brachiaria roots.     

Effects of P fertilization level on phosphorus uptake and agronomic traits under deficit irrigation in winter wheat (T. aestivum L.)

Abstract

Enhancing the phosphorus (P) use efficiency is critical for the sustainable cultivation of winter wheat. In this study, we investigated the effects of P fertilization level on plant P-uptake and agronomic traits under deficit irrigation, by using two wheat cultivars sharing contrasting water responses (i.e., Jimai 585 and Shimai 22). The high P level treatment (P120) improved plant biomass and P accumulation at each growth stage, grain yields, P remobilization amount to grain (PRA), P remobilization rate (PRR), and P contribution rate (PRR) of the cultivars with respect to the low P treatments (i.e., P90 and P60). Compared with Jimai 585, a cultivar acclimated to affluent water, the drought tolerant cultivar Shimai 22 exhibited similar behaviors on plant biomass, P-associated traits at each stage, and agronomic traits at maturity under P120. However, Shimai 22 was more improvement on P-associated and agronomic traits than Jimai 585 under P60 and P90. P contents were increased whereas moisture contents decreased in soil profile treated by P120 with respect to those by P60. Meanwhile, the soil profile cultivated by Shimai 22 displayed reduced moisture and P contents under P deprivation (i.e., P90 and P60) respect to that by Jimai 585, suggesting the contribution of more consumption of soil P and water storage to improved agronomic traits of Shimai 22. Together, our investigation suggested that suitable P input management positively mediates plant P-associated traits and grain formation capacity under deficit irrigation by improving supply and internal translocation of P across tissues in winter wheat plants.     

An investigation of the impact of Glomus clarum (mycorrhiza) on the growth of tomato (Lycopersicum esculentum mill.) on both sterilized and non-sterilized soils

Abstract

A greenhouse experiment was carried out to investigate the influence of Glomus clarum (mycorrhiza) on the growth of tomato seedlings grown in both sterilized and non-sterilized soils. Highest growth parameter values were recorded in tomato plants inoculated with mycorrhiza but grown in sterilized soil, followed by those grown in non-sterilized soil but inoculated with mycorrhiza also. Sterilized but non-inoculated tomato plants also had growth and were closely followed by non-sterilized, non-inoculated tomato plants. There was no significant difference in all the treatments when girth of the tomato plants used was measured in this study. Nutrient uptake (N,P,K) was significantly found highest in the inoculated sterilized tomato plants while it was found lowest in the non-sterilized, non-inoculated tomato plants. Generally, mycorrhizal-inoculated tomato plants (whether sterilized or non-sterilized) showed better growth in all the treatments used.