Polymer coated DAP helps in enhancing growth,yield and phosphorus use efficiency of wheat (Triticum aestivum L.)

Low phosphorus use efficiency (PUE) is one of the major reasons of poor wheat production worldwide. Among the various approaches used to enhance PUE, polymer coated fertilizers are relatively a new concept. Keeping this in view, a field study was conducted to evaluate polymer coated di-ammonium phosphate (DAP) to enhance growth, yield and PUE of wheat. Commercial DAP and polymer coated DAP (50%, 75% and 100% of recommended dose) were tested in wheat. Results revealed that application of 50% polymer coated DAP produced the same results or higher than 100% commercial DAP. However, the maximum increase in growth (plant height, root length, number of tillers m^?2, inter-nodal distance), yield (number of grains per spike, 1000 grain weight, grain yield and biological yield) and phosphorus acquisition by wheat was observed with 100% polymer coated DAP. Moreover, 100% polymer coated DAP increased phosphorus recovery and agronomic efficiency compared to other treatments.     

磷素子粒生产效率不同品种的小麦磷素吸收利用差异

盆栽试验研究了130份小麦不同生育时期的干物重、磷素含量、子粒产量等指标,采用组内最小平方和的动态聚类方法将供试品种按磷素子粒生产效率从低到高依次分为Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ和Ⅵ 6个类型,研究不同类型磷素吸收利用的差异。结果表明: 1）供试品种的磷素子粒生产效率差异较大（CV=1660%）,Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ和Ⅵ类品种的平均磷素子粒生产效率为P 13629、15167、16916、18589、20132、24466 g/g。子粒产量随磷素子粒生产效率提高呈增加趋势（r=03203**）。2）不同生育时期,小麦植株磷浓度与吸磷量类型间差异显著或极显著。成熟期磷素子粒生产效率与植株磷浓度极显著正相关（r=06969**）,子粒产量与抽穗期、成熟期植株吸磷量显著或极显著相关（r=02966*、r=09271**）。3）不同生育时期磷素干物质生产效率的类间差异均达显著水平; 成熟期磷素干物质生产效率与磷素子粒生产效率极显著正相关 （r=07391**）。4）拔节期、抽穗期和成熟期干物重均表现出随磷素子粒生产效率增加而增加的趋势,成熟期尤为突出。拔节期成熟期磷素吸收量是影响子粒产量形成的重要因素,磷素子粒生产效率高的品种在拔节期后有较强干物质和子粒产量形成能力。     

Introduction of composted rock phosphate and poultry manure enhances winter wheat phosphorus use efficiency,grain yield and soil quality

This field study evaluates the integrated impact of poultry manure (PM), rock phosphate (RP), composted rock phosphate (CRP) and single super phosphate (SSP) on the growth, yield, and phosphorus use efficiency (PUE) of winter wheat and their effect on postharvest soil characteristics. The seven treatments were as follows: T₁ = control; T₂ = SSP full; T₃ = PM full; T₄ = RP full; T₅ = CRP full; T₆ = 50% SSP + 50% CRP (50:50); T₇ = 50% PM + 50% CRP (50:50) at a recommended P rate of 90 kg ha^?1. The combined treatment with PM + CRP produced the highest straw yield of 3582 kg ha^?1, grain yield of 2226 kg ha^?1, P uptake of 21.3 kg ha^?1, and PUE of 18%. The postharvest soil organic carbon, total nitrogen and soil available phosphorus were sig-nificantly higher in integrated treatments.     

Improvement of wheat (Triticum aestivum) drought tolerance by seed priming with silicon

Silicon has the potential to improve drought tolerance in crops. Seeds primed with silicon were used in the present study to explore its potential benefit to withstand water stress. Seeds of two wheat varieties, NARC-2009 and Chakwal-50, were sown in pots after priming with distilled water and different concentrations (0.5%, 1.0% and 1.5%) of silicon sources (silicic acid, sodium silicate and silica gel) at PMAS, Arid Agriculture University, Rawalpindi. Maximum silicon uptake at three-leaf stage (0.028 µg g^?1 dry weight (DW)), anthesis (0.072 µg g^?1 DW) and maturity (0.103 µg g^?1 DW) was recorded for silica gel. Silicon uptake increased significantly in response to increase in Si concentration from 0.5% to 1.5%. Leaf membrane stability index, epicuticular wax, relative water content and proline remained maximum – 78.90%, 2.6 mg g^?1 DW, 83.88% and 54.90 µg g^?1 – for silica gel treatments compared with others. Silica gel with 1.5% silicon concentration resulted in maximum spike length (14.3 cm), biological yield (7.63 g pot^?1), hundred-grain weight (3.97 g pot^?1) and grain yield (2.46 g pot^?1). Based on the study outcomes, it is concluded that silica gel might be a good priming option with 1.5% silicon concentration to establish plant under drought stress.     

Root architectural responses of wheat cultivars to localised phosphorus application are phenotypically similar

Differences in nutrient recovery from fertiliser bands may improve cereal variety selection. The objective of this study was to identify the variation in root plasticity across commonly grown Australian wheat (Triticum aestivum L.) cultivars in response to a phosphorus (P)‐enriched band. Ten wheat cultivars were screened for root proliferation within a 150 mg P kg⁻¹ band in P‐responsive soil. Plants were destructively harvested at the four‐leaf phenological stage and various growth parameters, including root length density (RLD), were measured on banded and uniformly adequate P treatments. All wheat cultivars increased RLD between three and nine times in the P band. However, there was no significant difference in root plasticity among the cultivars tested. Although all cultivars produced longer, though ≈ 9% thinner roots when responding to the P band, the phenotypic response was unable to compensate fully for the lower P status encountered in the soil. Despite 23% longer root lengths in the P‐band treatments, P uptake per unit root length was 78% lower than in uniformly adequate P treatments. Our results indicate that root plasticity of wheat cultivars in a P‐enriched band was phenotypically similar. Further research is necessary before selecting for wheat cultivars that respond to localised nutrient patches with increased RLD.     

Foliar Applied Phosphorous Enhanced Growth,Chlorophyll Contents,Gas Exchange Attributes and PUE in Wheat (Triticum aestivum L.)

A pot experiment was conducted to evaluate the foliar applied phosphorous with and without pre-plant dose (50 kg hac.^?1) of phosphorous on growth, chlorophyll contents, gas exchange parameters and phosphorous use efficiency (PUE) of wheat. The experiment was conducted in net house at Department of Crop Physiology, University of Agriculture Faisalabad, Pakistan. Two promising wheat cultivar AARI 2011 and FSD 2008 were used as a test crop with 5 foliar phosphorus (P) rates (0, 2, 4, 6, 8 kg ha^?1). The foliar applied P with pre-plant performed better than without pre-plant and control treatments. Foliar treatment of phosphorus at 6 kg ha^?1 P proved to be the best among other foliar treatments followed by 8 kg ha^?1 P. The foliar application of phosphorous at 6 kg hac.^?1 with pre-plant soil applied P increased the shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight. The chlorophyll contents (Chl. a and b) were increased with the foliar application of phosphorous. The gas exchange parameters (net carbon dioxide (CO₂) assimilation rate, transpiration rate, stomatal conductance and sub-stomatal CO₂ rate) were significantly improved by foliar applied P. The maximum values of net CO₂ assimilation rate (5.27 μ mol m^?2 sec.^?1), transpiration rate (3.44 μ mol m^?2 sec.^?1), stomatal conductance (0.81 μ mol m^?2 sec.^?1) and sub-stomatal CO₂ (271.67 μ mol m^?2 sec.^?1), were recorded in the treatment where P was foliar applied at 6 kg hac.^?1 with pre-plant soil applied Phosphorous. The foliar application of phosphorous with pre-plant soil applied P enhanced Phosphorous use efficiency (PUE) in both varieties. The maximum value of PUE (15.42%) was recorded in the treatment where foliar feeding of P was done at 6 kg hac.^?1 with pre-plant soil applied P in both genotypes.     

Phosphorus use efficiency of improved faba bean (Vicia faba) varieties in low‐input agro‐ecosystems

The use of phosphorus (P)‐efficient legumes is a prerequisite for sustainable intensification of low‐input agro‐ecosystems. A study was undertaken in a farmer's field in the tropical highlands of Ethiopia to assess the agronomic performance, P acquisition efficiency (PAE), and P utilization efficiency (PUE) of six improved faba bean varieties (Vicia faba L. var. CS‐20DK, Degaga, Gebelcho, Moti, Obse, Walki) without and with P application. Varieties showed significant variations in PUE, but P application had no significant effect on PUE. Variety Moti demonstrated highest PUE of 272 kg grain kg^?1 P, which was 1.6‐fold higher than the lowest PUE (164 kg grain kg^?1 P) of Gebelcho. PUE was significantly and positively correlated with grain yield (r = 0.542) and negatively correlated with shoot PAE (r = –0.541), indicating that PUE is important for grain yield. The results demonstrate that variations in grain and biomass yield of faba beans were largely due to differences in PUE and not due to PAE. Therefore, we argue that genetic resources of faba bean varieties showing optimal agronomic performance and high PUE in low‐input agro‐ecosystems should be better explored. Introduction of such varieties in low‐input cereal‐based cropping systems could improve and enhance P use efficiency at the system level.     

Contribution of fertilisation,precipitation, and variety to grain yield in winter wheat on the semiarid Loess Plateau of China

Wheat yield is influenced by fertilisation, precipitation and variety, among other factors. There is limited research identifying the most important factors affecting wheat yield and assessing their relative importance in the long run. In this study, we evaluated the contribution of fertilisation, precipitation and variety to wheat yield using a long-term field experiment (1984–2014) on the semiarid Loess Plateau in China. The experiment consisted of six treatments: fertilisation with nitrogen (N), phosphorus (P), manure (M), NP, NPM, and a control without fertilisation. We monitored the yield of three varieties of winter wheat over time and assessed the changes in grain yield, soil properties, fertiliser-contribution rate (FCR) and precipitation-use efficiency (PUE) with different fertilisation treatments and precipitation patterns. Stepwise multiple linear regression was used to identify the most important factors affecting wheat yield and examine their relative importance. The results showed that fallow-season precipitation and annual precipitation (AnP) positively correlated with wheat yield in the N, M, NP, and NPM treatments. The amount of fertilisation, AnP, and monthly precipitation of February and September were included in the linear regression model; however, the influence of variety on yield could be ignored. With 30 years of fertilisation, soil organic matter, total nitrogen, and available potassium levels with NPM was higher than the control by 70.6%, 70.5%, and 319.2%, respectively. Yield, FCR, and PUE with M increased annually at rates of 89?kg?ha^?1?y^?1, 1.47?kg?kg^?1?y^?1, and 0.13?kg?mm^?1?y^?1, respectively. The yields and FCR, but not PUE, of all fertilised treatments were higher in wet than normal and dry years. The FCR with P was negative in all the three precipitation patterns. This study has implications for maximising the long-term winter yield with various factors in the rain-fed winter wheat cropping system of the Loess Plateau.     

Impact of Arbuscular-Mycorrhizal Fungi on Phosphorus Efficiency of Wheat,Rye, and Triticale

Genotypic variation and mycorrhiza play an important role in plant uptake of phosphorus (P). A pot experiment was conducted with three cereals, wheat (Triticum aestivum L. cv. PBW-34), rye (Secale cereale L. cv. R-308), and triticale (Triticale octoploide L. cv. DT-46), a hybrid of wheat and rye, to examine the genetic variation in the degree of arbuscular-mycorrhizal (AM) infection and its inheritability from parents (wheat and rye) to their progeny (triticale). The soil used for pot culture was low in available P (7.8 mg P kg^?1soil). Inoculation with AM fungi showed a significant increase in extent of root colonization for all three cereals (average 70%) compared with their performance without AM (average 19.1%). However, among the three cereals, this increase was significantly greater in rye than in the other two crops, while wheat and triticale did not differ significantly. Mycorrhizal infection resulted in 1.6, 1.7, and 1.8-fold increases in shoot, root, and total plant dry matter, respectively, compared with the un-inoculated treatment. Among the three cereals, rye recorded maximum shoot, root, and total plant dry mass and P content with AM inoculation. The P uptake by wheat, rye, and triticale was 10%, 64%, and 35%, respectively, higher with rather than without mycorrhizal infection. Rye was most responsive to AM inoculation, with mycorrhizal dependency of 193%; here again, triticale followed wheat, with similar mycorrhizal dependency. Rye showed an increase in P utilization efficiency (PUE) without AM inoculation while the PUE of triticale was intermediate between wheat and rye. High efficiency of AM symbiosis in terms of P uptake exists in rye and most of these traits in triticale seem to be inherited from wheat rather than rye.     

Identification and selection of low-phosphate-tolerant germplasm in barley (Hordeum vulgare L.)

Phosphorus (P) deficiency is one of the major constraints to crop yield worldwide, and genotypes or cultivars with high phosphate use efficiency (PUE) sustain growth when exposed to phosphate stress. Therefore, it is imperative to develop the genotypes or cultivars with high PUE. A pot experiment was conducted to evaluate the PUE among 150 barley (Hordeum vulgare L.) genotypes. Two high-tolerant and -sensitive accessions were selected. These two candidate materials were used to investigate the differences among the root morphology characteristics, antioxidant enzyme activity, inorganic phosphate (Pi) content and gene expression of HvPT5 under P-deficiency and P-sufficiency conditions. The values of these parameters were higher in the low-P-tolerant genotype than in the sensitive one. In pot experiment 1, all genotypes showed a significant difference in low-P tolerance, with variety GN121 achieving the highest tolerance, and GN42 being most sensitive. The results of this study may provide elite genetic germplasms for future work on isolation of P-related genes, and the improvement of PUE in barley.

Abbreviations: PUE: phosphate use efficiency; CAT: catalase; POD: peroxidase; SOD: superoxide dismutase; DMSO: dimethyl sulphoxide; MDA: malondialdehyde; TOPSIS: technique for order preference by similarity to an ideal solution; MCDM/MADM: multi-criteria (or attribute) decision making     

Grain phosphorus and phytate contents of wheat genotypes released during last 6 decades and categorization of selected genotypes for phosphorus use efficiency

Grain phosphorus (P) and phytate contents are important for early growth and quality of wheat, respectively. We studied seed P and phytate contents of 57 wheat genotypes released during last 6 decades. The grain total P and phytate P concentrations ranged from 2.0 to 8.9 mg g^?1 and 1.6 to 4.7 mg g^?1, respectively. Grain P was higher in genotypes released in current or last decade than pre-green revolution period and it correlated well with grain phytate contents. Indicating that breeders worked only for increased grain P and did not consider the phytate contents. Twenty-five genotypes were selected based on differences in grain P and phytate contents to observe the P use efficiency under field conditions. Genotypes differed significantly for grain P and yield at both 0 and 60 kg ha^?1 P levels. In conclusion, phytate fraction in grains of recent wheat genotypes was more as compared to old genotypes and genotype Inqlab-91 and Chakwal-86 had maximum grain total P. Moreover, number of productive tillers, spikelet per spike, grain weight, harvest index and grain P concentration and uptake were found responsible for P tolerance under P deficiency.     

EFFECT OF DIFFERENT PHOSPHORUS SOURCES ON THE GROWTH,YIELD, ENERGY CONTENT AND PHOSPHORUS UTILIZATION EFFICIENCY IN MAIZE AT RAWALAKOT AZAD JAMMU AND KASHMIR,PAKISTAN

Effect of poultry manure (PM) and four inorganic phosphorus (P) fertilizers sources, i.e., diammonium phosphate (DAP), single super phosphate (SSP), nitrophos (NP) and triple super phosphate (TSP) on crop production and P utilization efficiency (PUE) of maize was studied. Both inorganic P fertilizers and PM applied alone or combined in 50:50 proportions at equivalent rate of 90 kg P₂O₅ ha^?1. Results indicated that inorganic P sources with PM significantly increased plant height, leaf area and chlorophyll content. Average values showed that combined application of inorganic P with PM increased grain yield by 19 and 41% over inorganic P and PM alone, respectively. Similarly, increase in P-uptake due to the combined application of inorganic P + PM was 17% compared to sole inorganic P. Phosphorus utilization efficiency of inorganic P was increased with PM and the highest PUE was recorded in DAP + PM. Generally, combination of DAP + PM proved superior over the remaining P fertilizers.     

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.     

Enhancing phosphorus availability,soil organic carbon,maize productivity and farm profitability through biochar and organic–inorganic fertilizers in an irrigated maize agroecosystem under semi‐arid climate

Biochar amendments offer promising potential to improve soil fertility, soil organic carbon (SOC) and crop yields; however, a limited research has explored these benefits of biochar in the arid and semi‐arid regions. This two‐year field study investigated the effects of Acacia tree biomass‐derived biochar, applied at 0 and 10 t ha^?1 rates with farmyard manure (FYM) or poultry manure (PM) and mineral phosphorus (P) fertilizer combinations (100 kg P ha^‐1), on maize (Zea mays L.) productivity, P use efficiency (PUE) and farm profitability. The application of biochar with organic–inorganic P fertilizers significantly increased soil P and SOC contents than the sole organic or inorganic P fertilizers. Addition of biochar and PM as 100% P source resulted in the highest soil P (104% increase over control) and SOC contents (203% higher than control). However, maize productivity and PUE were significantly higher under balanced P fertilizer (50% organic + 50% mineral fertilizer) with biochar and the increase was 110%, 94% and 170% than 100%‐FYM, 100%‐PM and 100% mineral fertilizer, respectively. Maize productivity and yield correlated significantly positively with soil P and SOC contents These positive effects were possibly due to the ability of biochar to improve soil properties, P availability from organic–inorganic fertilizers and SOC which resulted in higher PUE and maize productivity. Despite the significant positive relationship of PUE with net economic returns, biochar incorporation with PM and mineral fertilizer combination was economically profitable, whereas FYM along biochar was not profitable due to short duration of the field experiments.     

Understanding the response of sorghum cultivars to nitrogen applications in the semi-arid Nigeria using the agricultural production systems simulator

Abstract

The Agricultural Production Systems simulator (APSIM) model was calibrated and evaluated using two improved sorghum varieties conducted in an experiment designed in a randomized complete block, 2014–2016 at two research stations in Nigeria. The results show that the model replicated the observed yield accounting for yield differences and variations in phenological development between the two sorghum cultivars. For early-maturing cultivar (ICSV-400), the model indicated by low accuracy with root means square error (RMSE) for biomass and grain yields of 20.3% and 23.7%. Meanwhile, Improved-Deko (medium-maturing) cultivar shows the model was calibrated with low RMSE (11.1% for biomass and 13.9% for grain). Also, the model captured yield response to varying Nitrogen (N) fertilizer applications in the three agroecological zones simulated. The N-fertilizer increased simulated grain yield by 26–52% for ICSV-400 and 19–50% for Improved-Deko compared to unfertilized treatment in Sudano-Sahelian zone. The insignificant yield differences between N-fertilizer rates of 60 and 100 kgha^?1 suggests 60 kgNha^?1 as the optimal rate for Sudano-Sahelian zone. Similarly, grain yield increased by 23–57% for ICSV-400 and 19–59% for Improved Deko compared to unfertilized N-treatment while the optimal mean grain yield was simulated at 80 kgNha^?1 in the Sudan savanna zone. In the northern Guinea savanna, mean simulated grain yield increased by 8–20% for ICSV-400 and 12–23% for Improved-Deko when N-fertilizer was applied compared to unfertilized treatment. Optimum grain yield was obtained at 40 kgha^?1. Our study suggests a review of blanket recommended fertilizer rates across semi-arid environments for sorghum to maximize productivity and eliminate fertilizer losses, means of adaptation strategies to climate variability.     

Effect of Foliar Application of Phosphorus on Winter Wheat Grain Yield,Phosphorus Uptake,and Use Efficiency

ABSTRACT

One would expect foliar applied phosphorus (P) to have higher use efficiencies than when applied to the soil, but limited information is available concerning this. Experiments were conducted in 2002, 2003, and 2004 to determine the effect of foliar applications of P on winter wheat grain yields, P uptake, and use efficiency. Twelve treatments containing varying foliar P rates (0, 1, 2, and 4 kg ha^{? 1} in 2002 and 2003 and additional 8, 12, 16, and 20 kg ha^{? 1} in 2004) with and without pre-plant rates of 30 kg ha^{? 1} were evaluated. Foliar applications of P at Feekes 7 generally increased grain yields and P uptake versus no foliar P. Use efficiency was higher when P was applied at Feekes 10.54. Results from this study suggested that low rates of foliar applied P might correct mid-season P deficiency in winter wheat, and that might result in higher P use efficiencies.     

施磷量对不同磷效率小麦氮、磷、钾积累与分配的影响

在土培盆栽条件下,以磷高效小麦(CD1158-7、省A3宜03-4)和磷低效小麦(渝02321)为材料,研究了不施磷、施磷(P)10、20和30mg/kg对小麦不同生育时期生物量、籽粒产量及氮、磷、钾的积累与分配的影响。结果表明:(1)随施磷量的减少,不同磷效率品种小麦籽粒产量和生物量均减少;同一施磷处理,磷高效品种籽粒产量和生物产量高于磷低效基因型。不施磷、施磷10mg/kg,高效品种CD1158-7、省A3宜03-4的籽粒产量为低效品种渝02321 的1.84 倍和1.74倍、1.64倍和1.27倍。(2)低磷处理,磷高效品种小麦植株能够积累较多的氮素;扬花期之前,磷高效品种氮素积累量占小麦全生育期积累量的比例高于低效品种。拔节期、孕穗期氮素分配比例为叶>茎>根,扬花期为叶>茎>穗>根,而成熟期为籽粒、颖壳>茎>叶>根。拔节期和孕穗期磷高效品种根的氮素分配比例高于低效品种,而扬花期和成熟期磷高效品种穗(籽粒)氮素分配比例较高。(3)小麦植株磷素积累量主要集中在拔节期以后的生育时期,占全生育期的82.32%~94.23%。低磷处理,高效品种在拔节期和孕穗期磷素积累量高于低效品种,孕穗期尤为突出。扬花期之前,不施磷处理下,磷高效品种根的磷素分配比例较高。(4)不同施磷处理下,拔节期、孕穗期及扬花期,磷高效品种小麦的钾积累量高于低效品种。不同器官钾素分配比例拔节期和孕穗期均为叶>茎>根,扬花期为茎>叶>穗>根,成熟期为茎>叶>籽粒、颖壳>根。磷高效品种在颖壳和籽粒的钾素分配比例高于低效品种。     

Influence of Biochars on Yield and Nitrogen and Phosphorus Use Efficiency of Pisum sativum under Groundwater and Wastewater Irrigation in Arid Climate

ABSTRACT

Present study evaluated the influence of slow-pyrolyzed wood-derived and cow manure-derived biochars on growth performance (i.e., yield production, nitrogen use efficiency (NUE), and phosphorus use efficiency (PUE)) of Pisum sativum under groundwater and municipal wastewater irrigation. Biochars were applied at 5, 10, and 15 t ha^?1 rates for 2 years. The amendment of biochars did not enhance yield during first year under both irrigation types; rather, small-particle-sized (<0.65 mm) wood-derived biochar reduced significantly yield at higher application rates under groundwater irrigation. During second year, amendment of biochars significantly increased the yield especially at higher application rates under groundwater irrigation while no influence of biochars was observed for wastewater irrigation treatment. The yield was significantly lower under wastewater irrigation for all treatments as compared to first year. The NUE and PUE of pods and stover were not different during first year and second year under both irrigation treatments except for the small-particle-sized wood-derived biochar applied at 10 and 15 t ha^?1, which tended to reduce significantly the NUE and PUE of pods and stover under groundwater irrigation during first year of cropping. The NUE and PUE were significantly lower during following year under wastewater irrigation. Our results suggest that amendment of biochars had positive influence on the growth of P. sativum under groundwater irrigation during second year of cropping while these amendments had no influence under wastewater irrigation.     

Elevated CO2 Improves Growth and Phosphorus Utilization Efficiency in Cereal Species Under Sub-Optimal Phosphorus Supply

Cultivars of Triticum aestivum, T. durum, and Secale cereale were grown at low (2 μM) and sufficient (500 μM) phosphorus (P) under ambient carbon dioxide (380 μmol mol^?1; aCO₂) and elevated CO₂ (700 μmol mol^?1, eCO₂) to study responses of cereal species in terms of growth and P utilization efficiency (PUE) under P x CO₂ interaction. Dry matter accumulation increased under eCO₂ with sufficient P. Nevertheless, dry matter accumulated at eCO₂ with low-P was similar to that obtained at aCO₂ with sufficient P. Leaf area was 43% higher under eCO₂ with sufficient P. Significant increase in lateral root density, length and surface area were noted at low-P under eCO₂. Phosphorus use efficience (PUE) increased by 59% in response to eCO_2­ in low-P plants. Thus, eCO₂ can partly compensate effect of low-P supply because of improved utilization efficiency. Among cereals, durum wheat was more suitable in terms of PUE under high CO₂ and limiting P supply.     

Soil and Plant Responses to the Application of Ascophyllum nodosum Extract to No-Till Wheat (Triticum aestivum L.)

A field trial consisting of four granule formulation doses and five liquid formulation sprays of a seaweed extract from Ascophyllum nodosum commercially known as Biovita, along with the recommended dose of nitrogen (N)–phosphorus (P)–potassium (K), was conducted during 2008 and 2009 in BHU, Varanasi, India, to evaluate its effect on wheat (var. HUW 468) under a no-tillage system. Among the granule doses, the 10 kg ha^?1 basal application and the two liquid sprays of 500 cm³ ha^?1 each at 25 and 50 days after sowing significantly improved the performance of wheat. On an average under these two treatments, the greatest grain and straw yields were observed were 3454.5, 3446.5 and 5187.5, 5220.0 kg ha^?1, respectively. The greatest protein content was found when further high doses of extract were applied. A faster decomposition of the paddy residue was also observed as indicated by an earlier decline in carbon (C)/N ratio of the soil in the treated plots.