Zinc Efficiency of Wheat Cultivars Grown on a Saline Calcareous Soil

Abstract

Zinc (Zn) deficiency is a yield limiting constraint for wheat production in central Iran. A field experiment was conducted for two consecutive years (1999/2000 and 2000/2001) to study Zn use efficiency of five wheat cultivars. Two Zn rates were used, i.e., 0 and 40 kg Zn ha^?1 applied as zinc sulfate. Significant variation was found among wheat cultivars in relation to grain yield, straw yield, Zn use efficiency and yield components. Based on grain yield and Zn use efficiency across two years, cultivar Cross was most efficient and Dur-3 was most inefficient for Zn use efficiency. Cultivars Kavir, Falat, and Rushan were intermediate in Zn use efficiency. Zinc concentration and uptake were higher in the zinc efficient cultivar Cross, while these values were lowest in the Zn inefficient cultivar Dur-3.     

APPLICATION OF INCREASING LEVELS OF ZINC TO SOIL REDUCED ACCUMULATION OF CADMIUM IN LUPIN GRAIN

Yellow lupin (Lupinus luteus L.) and narrow-leafed lupin (L. angustifolius L.) are grown as grain legumes in rotation with spring wheat (Triticum aestivum L.) on acidic sandy soils of south-western Australia. Yellow lupin can accumulate significantly larger cadmium (Cd) concentrations in grain than narrow-leafed lupin. A glasshouse experiment was undertaken to test whether adding increasing zinc (Zn) levels to soil increased Zn uptake by yellow lupin reducing accumulation of Cd in yellow lupin grain. Two cultivars of yellow lupin (cv. ‘Motiv’ and ‘Teo’) and 1 cultivar of narrow-leafed lupin (cv. ‘Gungurru’) were used. The soil was Zn deficient for grain production of both yellow and narrow-leafed lupin, but had low levels of native soil Cd (total Cd <0.05 mg kg^?1) so 1.6 mg Cd pot^?1, as a solution of cadmium chloride (CdCl₂·H₂O), was added and mixed through the soil. Eight Zn levels (0–3.2 mg Zn pot^?1), as solutions of zinc sulfate (ZnSO₄·7H₂O), were added and evenly mixed through the soil. Yellow lupin accumulated 0.16 mg Cd kg^?1 in grain when no Zn was applied, which decreased as increasing Zn levels were applied to soil, with ～0.06 mg Cd kg^?1 in grain when the largest level of Zn (3.2 mg Zn pot^?1) was applied. Low Cd concentrations (<0.016 mg Cd kg^?1) were measured in narrow-leafed lupin grain regardless of the Zn treatment. When no Zn was applied, yellow lupin produced ～2.3 times more grain than narrow-leafed lupin, indicating yellow lupin was better at acquiring and using indigenous Zn from soil for grain production. Yellow lupin required about half as much applied Zn as narrow-leafed lupin to produce 90% of the maximum grain yield, ～0.8 mg pot^?1 Zn compared with ～1.5 mg Zn pot^?1. Zn concentration in whole shoots of young plants (eight leaf growth stage) related to 90% of the maximum grain yield (critical prognostic concentration) was (mg Zn kg^?1) 25 for both yellow lupin cultivars and 19 for the narrow-leafed lupin cultivar. Critical Zn concentration in grain related to 90% of maximum grain yield was (mg Zn kg^?1) 24 for both yellow lupin cultivars compared with 20 for the narrow-leafed lupin cultivar.     

Effect of split application of zinc on yield of rice (Oryza sativa L.) in an inceptisol

Abstract

Rice is mostly transplanted under puddled low land soil conditions in India, where Zinc (Zn) deficiency is a common problem. The objective of this study was to find out the efficacy of split application of Zn on growth and yield of rice in an inceptisol. The split application of Zn as ZnSO₄ · 7H₂O performed better than its single basal application, while the split application of Zn-EDTA did not show any significant difference on yield and yield components of rice over its single basal application. Zn-EDTA was found to be better for growth and yield of rice among the two sources of Zn. The soil application of Zn at 1.0 kg ha^?1 as Zn-EDTA (T₇) recorded highest grain yield of 5.42 t ha^?1, filled grain percentage of 90.2%, 1000-grain weight of 25.41 g and number of panicles m^?2 of 452. The Zn content of grain and straw were found to be maximum in the treatment T₇ i.e. 38.19 and 18.27 mg kg^?1, respectively. Linear regression studies indicated that grain yield of rice is significantly influenced by Zn content of grain, Zn content of straw and DTPA extractable Zn content of soil at the level of 95.96, 96.74 and 95.57%, respectively.     

Evaluation of some rice cultivars’ response to salinity stress using resistance indices

Parts of paddy fields in Mazandaran Province, northern Iran, are confronted with soil and water salinity. To screen proper rice cultivars, an experiment was performed with eight modified rice cultivars under four levels of irrigation water salinity (1, 2, 4 and 6 dS m^?1) with three replications, in Amol, northern Iran. The objective of the present study was the evaluation of eight screening indices for identifying salinity tolerance of these cultivars, so that suitable cultivars can be recommended for the cultivation with saline irrigation water in paddy fields. To evaluate the resistance of these cultivars to salinity stress, different indices were calculated. The results showed that Khazar cultivar was the most salt-sensitive cultivar in all salinity levels. In the irrigation salinity levels of 2 and 4 dS m^?1 Neda cultivar and in the level of 6 dS m^?1 Dasht cultivar were the most salt-resistant cultivars. In the two irrigation salinity levels of 4 and 6 dS m^?1, the mean productivity index was the most effective in the screening of salt-resistant cultivars. Harmonic mean, geometric mean productivity, stress tolerance index and mean productivity indices were found to be the best indices in screening resistant cultivars.     

Increased yield of direct seeded rice (Oryza sativa L.) by foliar fertilization through multi-component fertilizers

Foliar application of fertilizers can guarantee the availability of nutrients to rice for obtaining higher yield. Rice responds favorably to macro- and micronutrients and the tolerance to salinity hazards improves by decreasing the N/S ratio. In this study, results showed that nutrient concentrations (g L^?1) for rice are: nitrogen (N) 108.0, phosphorous (P₂O₅) 6, potassium (K₂O) 81.0, calcium (CaO) 15.0, and magnesium (MgO) 6 g L^?1; and for iron (Fe), manganese (Mn), zinc (Zn), cupper (Cu), boron (B), molybdenum (Mo) and silicon (Si) the recommended concentrations are 0.6, 0.45, 0.21, 0.06, 0.09, 0.0002 and 0.004 g L^?1, respectively. A significant increase was recorded in number of panicles m^?2, 1000 grain weight, biological yield and grain yield with foliar application of nutrients. Five foliar applications of nutrients resulted in maximum number of panicles m^?2, grains panicle^?1, 1000 grain weight and biological yield. It is concluded that five foliar applications of balanced amounts of fertilizers at the seedling stage (two sprays), tillering (single spray) and at panicle initiation and panicle differentiation (two sprays) helped in enhancing yield and yield components of rice. In this research, five foliar applications produced the smallest damaging effects of blast (Pyricularia oryzae) in rice.     

Effects of zinc fertilizer amendments on yield and grain zinc concentration under controlled environment conditions

The application of zinc (Zn) fertilizer to lentil is an agronomic strategy that has the potential to improve yield and enhance grain Zn concentration. A pot study was conducted to determine if Zn fertilizer applied to three popular Saskatchewan lentil cultivars could increase yield and concentration of Zn in the grain. The effects of soil and foliar applied Zn forms, including ZnSO₄, Zn chelated with EDTA, Zn lignosulphonate, and a control were evaluated. Forms of Zn were not found to significantly increase yield (P = 0.828) or grain Zn concentration (P = 0.708) in any of the lentil cultivars tested. Fertilization with soil applied ZnSO₄ resulted in significantly (P < 0.0001) higher amounts of residual available Zn in the soil relative to other Zn treatments. Soil fertilized with ZnSO₄ had 1.13 mg kg^?1 diethylenetriaminepentaacetic acid (DTPA)-extractable Zn compared to 0.84 mg Zn kg^?1 and 0.77 mg Zn kg^?1 in the soil and foliar applied chelated Zn, respectively.     

Quantitative Caloric Energy Distribution and Variations in Two Rice Varieties Related to Different Nitrogen Application Levels in Paddy Field

Abstract

A field experiment was conducted in Hangzhou, Zhejiang Province, P.R. of China in 1999 to investigate the quantitative caloric energy characteristics of two rice cultivars (Oryza sativa L.), early crop rice Jia yu 948 and late crop rice Jia yu 93390 were grown in different nitrogen levels and climate conditions. The two cultivars were grown with 0, 80, 120, 160, and 200 kg ha^?1 of nitrogen fertilizer and in ample water and farming management activities. Analysis of caloric energy showed that significant differences occurred among treatments and plant organs in both rice cultivars. However, no significant differences occurred among same organs under different nitrogen treatments in both cultivars except for the panicles. The mean caloric energy of both cultivars increased with nitrogen fertilizer application. However, no optimal level of nitrogen fertilizer treatment with caloric energy was established, as there was still an increase in caloric energy even at 200 kg N ha^?1 fertilizer treatment. Cultivar Jia yu 948 had a higher mean caloric energy of 4172 cal g^?1 compared to 4117 cal g^?1 of cultivar Jia yu 93390. There were significant differences in caloric energy among the plant organs. The ascending order of energy distribution was as follows; root, stem, husk, leaf, grains, and panicles. Of great interest is the relatively high amount of energy invested in the husks. This amount was similar to that of the leaf. There was a linear relationship between caloric energy and nitrogen application levels. The basic rice caloric values are 4058 cal g^?1, an increase in 1 kg N ha^?1 of nitrogen (pure) resulted in an increase of 0.41 cal g^?1 and 0.29 cal g^?1 of dry weight in the cultivar Jia yu 948 and cultivar Jia yu 93390 respectively. Thus Jia yu 948 had a better utilization efficiency of nitrogen nutrient than Jia yu 93390 considering the caloric value increase.     

Assessment of salinity tolerance threshold for two wheat genotypes in response to zinc

Plants’ tolerance to salt stress is different among species, nevertheless, mineral nutrition might also affect it. A greenhouse experiment was conducted to evaluate the effect of Zinc (Zn) on salinity tolerance using a sigmoid response model in two wheat (Triticum aestivum L.) genotypes ‘Falat’ and ‘Bam’ with different salinity tolerances. The treatments consisted of three Zn rates (0, 5 and 10 mg Zn kg^?1) and five levels of soil salinity (1.1, 6.5, 12.3, 18.7 and 25.1 dS m^?1). The results showed that dry weight of straw and grain decreased, as salinity increased in both genotypes although this decrease in ‘Falat’ genotype was higher than that of ‘Bam’ genotype. Application of 10 mg kg^?1 Zn increased the dry weight by 25% (straw) and 32% (grain) in ‘Falat’ but 67% (straw) and 60% (grain) in ‘Bam’ as compared with the absence of added Zn. According to the fitted function, in the absence of Zn, grain production began to decline at EC_e-values of 4.7 dS m^?1 in ‘Falat’ genotype, and 7.5 dS m^?1 in ‘Bam’ genotype. Application of Zn led to a decrease of salinity tolerance in ‘Falat’ genotype, but an increase in ‘Bam’ genotype. The study found that Zn application under saline conditions, depending on genetic differences of wheat genotypes, would have different effects on their tolerance to salinity.     

Salt Tolerance of Four Potato Cultivars

Abstract

Tests are needed to evaluate the salt tolerance of new and untested potato cultivars under various cultural conditions. Two lysimeter experiments were conducted in two seasons to investigate the influence of irrigation water salinity on tuber yields of four potato (Solanum tuberosum L.) cultivars (Spunta, Alpha, Cara, and King Edward). Four salinity levels [EC_w 0.53 (control), 3.13, 6.25, and 9.38 dS m^?1] established by adding NaCI to fresh water, were used. Increasing irrigation water salinity reduced significantly total and average tuber yield for all cultivars in both seasons. Cara cultivar produced the highest tuber yield of all cultivars in both seasons. The salt tolerance curves of the potato cultivars in both seasons revealed that tolerant rating of the four cultivars can be assigned as follows: Cara > Alpha > Spunta > King Edward. The polynomial cubic equations developed for the four potato cultivars in fall and summer seasons were successful in predicting potato tuber yields response to irrigation water salinity.     

GENOTYPIC VARIATION FOR PRODUCTIVITY,ZINC UTILIZATION EFFICIENCIES,AND KERNEL QUALITY IN AROMATIC RICES UNDER LOW AVAILABLE ZINC CONDITIONS

Zinc (Zn) has emerged as the plant nutrient limiting rice growth in several parts of the world. About 50% of world soils are deficient in Zn and this is also true for India. An analysis of 0.233 million samples taken from different states showed that 47% of Indian soils are deficient in Zn. In India, Zn deficiency is widespread, especially in the rice–wheat cropping system belt of North India, which has high pH calcareous soils. Zinc is also now recognized as the fifth leading health risk factor is developing Asian countries, where rice is the staple food and Zn nutrition of humans and animals has recently received considerable attention. However, no reports are available on the effect of Zn fertilization on kernel quality of aromatic rices. The present study was therefore undertaken to study the effect of Zn fertilization on yield attributes, grain, and straw yield, Zn concentrations in grain and straw, Zn uptake, Zn use indices and kernel qualities of the aromatic rices. A field study at the Indian Agricultural Research Institute, New Delhi, India showed that Pusa Sugandh 4 (‘PS 4’) is a better than the earlier developed aromatic rice variety Pusa Basmati 1 (‘PB 1’) in terms of grain yield (4.08 tonnes ha^?1), kernel quality, zinc (Zn) concentrations in grain and Zn uptake (1,396.9 g ha^?1), recovery efficiency (5.2%), agronomic efficiency (122.7 kg grain increase kg^?1 Zn applied), partial factor productivity (1,064.7 kg grain kg^?1 Zn applied) and physiological efficiency (39,625 kg grain kg^?1 Zn uptake) of applied Zn. From the grain yield (4.64 tonnes ha^?1) viewpoint an application of 5 kg Zn ha^?1 was found sufficient for the aromatic rices grown on ustochrepts of north Indian rice-wheat cropping system belt. Application of 7.5 kg Zn ha^?1 increased Zn concentrations in the grain (37.0 mg kg^?1 DM) and straw (117.3 mg kg^?1 DM) of aromatic rices studied and this is important from the human and animal nutrition viewpoint under Indian conditions.     

Zinc accumulation in lettuce cultivars grown with organic or chemical based nutritional regimes

This study determined the potential to increase Zn density of lettuce (Lactuca sativa L.) through cultivar selection and nutrient management. Organic fertilizer and Hoagland and Arnon no.1 solution factored with three zinc (Zn) levels provided as zinc sulfate (ZnSO₄) were the fertilizer regimes in a greenhouse experiment. Modern cultivars had a 32% higher fresh head weight than heritage cultivars, but each accumulated the same Zn concentration (65 mg kg^?1 dry wt). Butterhead phenotypes had a 38% lower yield than loose-leaf and had the highest Zn concentration (78 mg kg^?1 dry wt) followed by romaine (66 mg kg^?1 dry wt) and loose-leaf (53 mg kg^?1 dry wt). Concentration of Zn did not differ between fertility regimes, being about 66 mg kg^?1 dry wt with each regime. Differences in Zn concentrations were significant among individual cultivars with ranges from 42 mg g^?1 dry wt to 91 mg kg^?1 dry wt. ‘Tom Thumb’, ‘Adriana’, ‘Claremont’, and ‘Focea’ were the top in cultivar ranking, with mean Zn concentration of 63 mg kg^?1 dry wt. The results signify that selection of cultivars may be utilized to increase Zn accumulation in lettuce but that nutritional regimes had little effect on accumulation.     

Zinc Tolerance in Wheat Cultivars as Affected by Varying Levels of Phosphorus

Abstract

The effect of zinc–phosphorus (Zn‐P) interaction on Zn efficiency of six wheat cultivars was studied. The higher dry matter yields were observed when Zn was applied at 5 µg g^?1 soil than with no Zn application. Phosphorus applications also increased dry matter yield up to the application of 25 µg P g^?1 soil. The dry matter yield was significantly lower at the P rate of 250 µg g^?1 soil. At the Zn‐deficient level, the Zn‐efficient cultivars had higher Zn concentrations in the shoots. Zinc concentrations in all cultivars increased when the P level in the soil was increased from 0 to 25 µg P g^?1 soil except for the cv. Durati, in which Zn concentrations decreased with increases in P levels. However, when Zn×P interactions were investigated, it was observed that at a Zn‐deficient level, Zn concentrations in the plant shoot decreased with each higher level of P, and more severe Zn deficiency was observed at P level of 250 µg g^?1 soil.     

Enhancing nutrient translocation,yields and water productivity of wheat under rice–wheat cropping system through zinc nutrition and residual effect of green manuring

Abstract

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice–wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5?×?10³ and 30.5?×?10³ L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5?×?10³, 47?×?10³ and 13?×?10³ L irrigation water per tonne wheat over residual effect of 5?kg Zn ha^?1 through chelated Zn-EDTA as soil application, 2.5?kg Zn ha^?1 through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering?+?flowering?+?grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.     

The effectiveness of seed priming and foliar application of zinc- amino acid chelates in comparison with zinc sulfate on yield and grain nutritional quality of common bean

Abstract

The efficacy of seed priming and foliar application of zinc-amino acid chelates including zinc-histidine [Zn(His)₂] and zinc-methionine [Zn(Met)₂] in comparison with zinc sulfate (ZnSO₄) on yield and grain nutritional quality of two common bean cultivars (Phaseolus vulgaris L., cvs Talash and Sadri) was investigated in a severely Zn-deficient calcareous soil (DTPA-Zn: 0.38?mg kg^?1 soil) in a pot experiment. Bean response to Zn application varied depending on the Zn fertilizer, application method and cultivar. In ‘Talash’, seed priming with [Zn(His)₂] and [Zn(Met)₂] led to 24.1 and 11.6% increase in the grain yield of bean in comparison with ZnSO₄ treatment, respectively. In both cultivars, foliar application of [Zn(His)₂] led to significant increase in the grain yield in comparison with ZnSO₄. The highest grain Zn concentration was obtained by seed priming with [Zn(Met)₂] in ‘Sadri’ and [Zn(His)₂] in ‘Talash’, respectively. For Zn-amino acid chelates, seed priming was more effective than foliar application in increasing grain yield and Zn concentration. Foliar application of [Zn(His)₂] and [Zn(Met)₂] in ‘Sadri’ and [Zn(Met)₂] in ‘Talash’ resulted in higher protein content in bean grain as compared with ZnSO₄. In both cultivars, foliar application of [Zn(Met)₂] was the more effective than seed priming to increase grain protein content. The highest water-soluble carbohydrates concentration of grain was obtained by seed priming with [Zn(Met)₂] and [Zn(His)₂] in ‘Sadri’ and ‘Talash’ cultivars, respectively. Therefore, seed priming with [Zn(His)₂] and ZnSO₄ in ‘Sadri’ and [Zn(Met)₂] in ‘Talash’ can effectively be used for improving yield of common bean in Zn-deficient calcareous soils.     

Zinc Biofortification in Sixty Groundnut Cultivars Through Foliar Application of Zinc Sulphate

A field experiment with 60 groundnut cultivars, in a calcareous soil having 1.20 mg kg^?1 available zinc (Zn), foliar application of 0.2% aqueous solution of zinc sulphate thrice at 40, 55 and 70 days at 500, 500 and 1000 L ha^?1, respectively, increased the number of pods, pod yield, shelling and 100 seed mass and seed zinc (Zn) content, significantly. The seeds Zn content in groundnut cultivars ranged 38–70 mg kg^?1 with an average of 48 mg kg^?1 without Zn and 58 mg kg^?1 with Zn. Foliar Zn application increased 22% Zn in seed. This increase was more than 10% in 48 out of 60 cultivars. The cultivars GG 7, GG 20, Tirupati 4, DH 8, JSP 19, TKG 19 A, CSMG 884 and S 206 showed > 50 mg kg^?1 Zn, > 10% increase in seed Zn with Zn application and > 250 g m^?2 pod yield.     

EFFECTS OF PHYTOHORMONES ON PROLINE CONTENT AND ANTIOXIDANT ENZYMES OF VARIOUS WHEAT CULTIVARS UNDER SALINITY STRESS

Salinity stress is one of the important agricultural problems in the world. A factorial experiment based on completely randomized design with four replications was conducted to evaluate the effects of phytohormones (gibberellic acid and abscisic acid) on the activity of antioxidant enzymes (peroxidase, superoxide dismutase and catalase), rubisco activity and content, and proline in three wheat cultivars (Gascogen, Zagros, and Kuhdasht) under control and salinity stress (3.5 and 7 dS m^?1). The results showed that salinity stress (3.5 and 7 dS m^?1) decreased the activity of catalase, rubisco, carboxylase, but increased peroxidase, superoxide dismutase activity and proline content. Gibberellic acid caused 58.03% increased in rubisco carboxylase activity in Zagros at 7 dS m^?1 in comparison with abscisic acid under salinity stress compared with the control plants in Kuhdasht. Activity of superoxide dismutase in Kuhdasht cultivar at 7 dS m^?1 salinity level showed 76.43% increased in Gascogen under salinity stress compared with the control plants with gibberellic acid application. The highest proline content as an osmolyte was found in Zagros at 7 dS m^?1 salinity level with abscisic acid (194 μmol g^?1 DM) application. Peroxidase activity increased 83.31% and catalase activity decreased 61.27% compared with the control plants in Zagros. Gibberellic acid application significantly prevented reduction in rubisco content under salinity stress. In conclusion, increased in peroxidase and superoxide dismutase activity and proline content decreased the adverse effects of salinity stress on studied cultivars. Also, the foliage spray of gibberellic acid enhanced and improved the growth condition. In this experiment, Zagros cultivar showed more tolerance to salinity stress than the other two cultivars.     

The variation of phosphorous content,grain yield,and rhizosphere microbial biomass among durum wheat cultivars under salinity stress

ABSTRACT

The effectiveness of plant–soil synergies is largely modulated by interaction between cultivar and rhizosphere microbiome. We evaluated the agronomic performance of six durum wheat cultivars, in two semi-arid locations in Tunisia that differed in their irrigation water salinity: S1 (6 dS m^?1) and S2 (12 dS m^?1). The two-consecutive-year field experiments assessed the effects of the microbial biomass carbon (MBC), leaf phosphorus (LP) and rhizosphere phosphorus (P) on the grain yield (GY) and yield components at tillering and flowering stages. Overall, in saline conditions, cultivars differed in above- and below-ground traits, particularly, with tolerant cultivars presenting relatively greater MBC, P and LP. Furthermore, in S2, GY positively correlated with MBC (r = 0.69), LP (r = 0.80) and P (r = 0.79). Additionally, in S2, MBC positively correlated with P (r = 0.87) and LP (r = 0.85) at flowering. This result was further confirmed by multiple linear regression (step-wise) analysis, which revealed that MBC and LP were the determinant components of GY variability under S2. The present study demonstrates that LP and soil P are mandatory for improving the management of durum wheat. Salinity tolerance was largely affected by the cultivars’ rhizosphere MBC.     

Summer green-manuring crops and zinc fertilization on productivity and economics of basmati rice (Oryza sativa L.)

Field experiments were conducted to study the effects of summer green-manuring crops and zinc (Zn) fertilization on the productivity and economics of Basmati rice. Sesbania aculeata summer green-manuring crop residue incorporation (SGMI) gave highest values of all the growth and yield attributes, grain and straw yield, viz. 3.58, 3.69 t ha^?1 and 16.14, 16.25 t ha^?1 of Basmati rice in 2008 and 2009. Among the Zn fertilization treatments, application of 2.0% Zn-enriched urea (ZEU) as ZnSO₄ · H₂O significantly influenced yield attributes and yield of Basmati rice during both years, and the increase in grain yield was 38.5 and 40.0% over absolute control (no N and no Zn) and 11.9 and 13.6% over control (only N) in both years of study. However, 2.0% ZEU (ZnO) was very close in terms of yield attributes and grain, straw yields of Basmati rice. As regards to the economics of Basmati rice, SGMI and 2.0% ZEU (ZnSO₄ · H₂O) Zn fertilization treatments gave the highest gross (SGMI, 85,985 and 91,582 INR ha^?1; 2.0% ZEU, 89,837 and 59,851 INR ha^?1) and net (SGMI, 56,997 and 61,445 INR ha^?1; 2.0% ZEU, 59,851 and 64,442 INR ha^?1) returns, respectively, compared with incorporation of the remaining summer green manuring residue and Zn fertilization treatments in 2008 and 2009. A significantly higher benefit:cost ratio was recorded with SGMI and 2.0% ZEU (ZnSO₄ · H₂O). Overall, Sesbania aculeata green manuring and 2.0% ZEU (ZnSO₄ · H₂O) are excellent sources of N and Zn for improved productivity of Basmati rice.     

Grain yield and nitrogen use efficiency of various modern rice cultivars grown at different nitrogen levels

Field trials were conducted to study the responses of grain yield and nitrogen (N) use efficiency at five input rates (N₀, N_82.5, N₁₆₅, N_247.5, and N₃₃₀ kg ha^?1) in a set of nine of the most representative rice cultivars. Grain yields of rice across the nine cultivars were increased significantly by N level. All the cultivars contained a significant linear plus plateau or quadratic relationship between N levels and grain yields.The minimum yields (means of 2 years) at N₀, N_82.5, N₁₆₅, N_247.5, and N₃₃₀ level all occurred in No. 2 cultivar. Compared with the grain yield of No. 2 at different N levels, those of the maximum cultivars increased by 37.1 (No. 8), 39.1 (No. 7), 48.4 (No.3), 43.3 (No. 4), and 43.9% (No. 3), respectively. In 2011, the highest average apparent nitrogen recovery efficiency (ANRE) in grain of the 4 N levels occurred in No. 3 cultivar (45.9%), followed by No. 4, No. 6, and No. 1, and the highest average agronomic efficiency (AE) in grain of the 4 N levels occurred in No. 9 cultivar [29.0 kg (kg N)^?1], followed by No. 3, No. 1, and No. 4. For the second-season planting, the highest average ANRE occurred in No. 4 cultivar (28.4%), followed by No. 3, No. 5, and No. 6, and the highest average AE occurred in No. 5 cultivar [18.1 kg (kg N)^?1], followed by No. 4, No. 3, and No. 7. Overall, No. 3 and No. 4 cultivars were the ideal ones that not only increased the grain yield but also improved the N use efficiency.     

Influence of arbuscular mycorrhizae on root colonization,growth and productivity of two wheat cultivars under salt stress

Two pot experiments were conducted in the greenhouse of the National Research Center, Egypt during 2003/2004 and 2004/2005 to investigate the efficacy of arbuscular mycorrhizae (AM) on root colonization, growth and productivity in two wheat cultivars, Sakha 8 and Giza 167, under salt stress. The extent of the AM effect on wheat development varied with plant cultivar and salinity level. Maximum root colonization and spore production were observed with the Sakha 8 cultivar, which resulted in greater plant growth and productivity at all salinity levels. AM and plant development were adversely affected by increasing salinity. However, the presence of mycorrhizal fungi protected wheat against the detrimental effect of salinity, and stimulated growth, productivity, total crude protein concentration and nitrate reductase activity. The average enhancement in grain yield due to AM inoculation was 76 and 68% at 0.15 mS cm^?1, 93 and 84% at 3.13 mS cm^?1, 130 and 115% at 6.25 mS cm^?1, and 154 and 120% at 9.38 mS cm^?1 salinity for Sakha 8 and Giza 167, respectively. In general, mycorrhizal inoculation enhanced the ability of wheat to cope with saline conditions and using AM inoculants can help plants to thrive in degraded arid/semi-arid areas.