Comparison of growth and nutrient uptake capacities of three dominant species of Qinhuangdao green tides

Since 2015, green tides have been blooming in offshore waters of Qinhuangdao, with serious impacts on the local ecological environment and tourism. Ulva australis, Bryopsis plumosa, and U. prolifera are the dominant species of Qinhuangdao green tides, following a sequential succession pattern. Ulva prolifera is the dominant species,with the highest biomass and the greatest influence on the local ecological environment. To study the reason of green tide dominant species succession and U. profilera became the dominant species with the largest biomass,we compared and analyzed the growth and nutrient uptake capacity of the three algae. The results showed that temperature significantly affects the growth of the three species. Within the temperature range of the experimental setup, the optimum temperature for the growth of U. australis, B. plumosa and U. profilera is10℃, 15℃, and 20–25℃, respectively. Combined with the temperature variation trend during green tide bloom development, we believe that temperature is the key environmental factor for the succession of the dominant species. Ulva prolifera has a higher growth rate than U. australis and B. plumosa under the same nitrate,ammonium, and phosphate levels. Significant differences in the maximum absorption rate(R_(max)) and R_(max)/Ks(the relationship between uptake rate and substrate concentration) values indicated that U. prolifera had an apparent competitive advantage over U. australis and B. plumosa regarding nutrient uptake. Therefore, the strong growth and nutrient uptake capacities of U. prolifera might be the main reason for becoming the dominant species with the largest biomass in Qinhuangdao green tides.

Effects of Nitrogen Application Level on Rice Nutrient Uptake and Ammonia Volatilization

The effects of different nitrogen application levels on nutrient uptake and ammonia volatilization were studied with the rice cultivar Zheyou 12 as a material.The accumulative amounts of nitrogen,phosphorus and potassium in rice plants across all growth stages showed a trend to increase with increasing nitrogen application levels from 0 to 270 kg/hm 2,but decreased at nitrogen application levels exceeding 270 kg/hm 2.Moreover,the accumulative uptake of nitrogen,phosphorus and potassium by the rice plants was increased by application of organic manure in combination with 150 kg/hm 2 nitrogen.The nitrogen uptake was high during the jointing to heading stages.Correlation analysis showed that rice yield was positively correlated with the accumulative uptake of nitrogen,phosphorus and potassium by the rice plants.The highest correlation coefficient observed was between the amount of nitrogen uptake and rice yield.The rate and accumulative amounts of ammonia volatilization increased with increasing nitrogen fertilizer application level.Compared with other stages,the rate and accumulative amount of ammonia volatilization were higher after base fertilizer application.The ammonia volatilization rates in response to the nitrogen application levels of 270 kg/hm 2 and 330 kg/hm 2 were much higher than those in the other treatments.The loss of nitrogen through ammonia volatilization accounted for 23.9% of the total applied nitrogen at the nitrogen application level of 330 kg/hm 2.

Nutrient deficiency limits population development,yield formation,and nutrient uptake of direct sown winter oilseed rape

Direct-sowing establishment method has great significance in improving winter oilseed rape（Brassica napus L.） production and guaranteeing edible oil security in China. However, nutrient responses on direct sown winter oilseed rape（DOR） performance and population development dynamic are still not well understood. Therefore, five on-farm experiments were conducted in the reaches of the Yangtze River（RYR） to determine the effects of nitrogen（N）, phosphorus（P）, and potassium（K） deficiencies on population density, dry matter production, nutrient uptake, seed yield, and yield components of DOR plants. Four fertilization treatments included the balanced NPK application treatment（NPK, 180 kg N, 39.3 kg P, 100 kg K, and 1.8 kg borax ha–1） and three nutrient deficiency treatments based on the NPK treatment, i.e., –N, –P, and –K. The results indicated that DOR population density declined gradually throughout the growing season, especially at over-wintering and pod-development stages. Nutrient deficiency decreased nutrient concentration in DOR plants, limited dry matter production and nutrient uptake, and thereby exacerbated density reduction during plants growth. The poor individual growth and reduced population density together decreased seed yield in the nutrient deficiency treatment. Averaged across all the experiments, seed yield reduced 61% by N deficiency, 38.3% by P deficiency, and 14.4% by K deficiency. The negative effects of nutrient deficiency on DOR performances followed the order of –N–P–K, and the effects were various among different nutrient deficiencies. Although N deficiency improved DOR emergence, but it seriously limited dry matter production and nutrient uptake, which in turn led to substantial plants death and therefore resulted in a very low harvested density. The P deficiency significantly reduced initial density, limited plants growth, and exacerbated density reduction. The K deficiency mainly decreased individual growth and yield, but did not affect density dynamic. Our results highlighted the importance of balanced NPK application in DOR production, suggesting that management strategy of these nutrients should be comprehensively considered with an aim to build an appropriate population structure with balanced plant density and individual growth.

Comparative short-term effects of sewage sludge and its biochar on soil properties, maize growth and uptake of nutrients on a tropical clay soil in Zimbabwe

Soil application of biochar from sewage could potentially enhance carbon sequestration and close urban nutrient balances. In sub-Saharan Africa, comparative studies investigating plant growth effect and nutrients uptake on tropical soils amended with sewage sludge and its biochar are very limited. A pot experiment was conducted to investigate the effects of sewage sludge and its biochar on soil chemical properties, maize nutrient and heavy metal uptake, growth and biomass partitioning on a tropical clayey soil. The study compared three organic amendments; sewage sludge （SS）, sludge biochar （SB） and their combination （SS＋SB） to the unamended control and inorganic fertilizers. Organic amendments were applied at a rate of 15 t ha-1 for SS and SB, and 7.5 t ha-1 each for SS and SB. Maize growth, biomass production and nutrient uptake were significantly improved in biochar and sewage sludge amendments compared to the unamended control. Comparable results were observed with F, SS and SS＋SB on maize growth at 49 d of sowing. Maize growth for SB, SS, SS＋SB and F increased by 42, 53, 47, and 49%, respectively compared to the unamended control. Total biomass for SB, SS, SS＋SB, and F increased by 270,428, 329, and 429%, respectively compared with the unamended control. Biochar amendments reduced Pb, Cu and Zn uptakes by about 22% compared with sludge alone treatment in maize plants. However, there is need for future research based on the current pot experiment to determine whether the same results can be produced under field conditions.

Effect of NPK Application on Yield,Nutrients and Water Utilization Under Sudangrass and Ryegrass Rotation Regime

Sudangrass and ryegrass rotation is a new type of cropping system in Jianghan Plain,which develops very fast in recent years.So,it is essential to work out the optimal nutrients and water management measures in this new system.The effect of NPK fertilizer on yield of forage grass,nutrients and water utilization under sudangrass and ryegrass rotation was studied through continuous pot experiments for three years.The results showed that NPK combination could significantly improve the yield of forage grasses.The total yields during the periods of 2005-2006,2006-2007 and 2007-2008 were 1 690.0,2 091.3 and 1 770.7 g/pot,respectively.The yields in PK treatment were 700.7,1 256.9 and 856.3% lower than those of NPK treatment,while the yields in NK treatment were 426.3,384.9 and 792.3% lower than those of NPK treatment,respectively.Similarly,the yields in NP treatment were 15.9,4.4 and 10.6% lower than those of NPK treatment,respectively.The NPK combination was found to improve the nutrients uptake,and the total N uptakes during the above periods were 10.0,14.8 and 10.6 times higher than that of PK treatment,respectively,and 3.7,1.8 and 5.1 times higher than those of NK treatment,respectively,but,were similar to NP treatment.The total P uptakes were 4.6,6.8 and 5.3 times higher than those of PK treatment,and were 2.4,2.3 and 2.9 times higher than those of NK treatment,respectively,but were similar to NP treatment.The total K uptakes were 5.2,8.4 and 4.9 times higher than that of PK treatment,3.9,2.3 and 3.9 times higher than those of NK treatment,and 80.9,57.4 and 200.5% higher than those of NP treatment,respectively.Water productivity for three years time periods were 16.5,16.1 and 16.2 kg m-3,and were 3.8,5.4 and 4.2 times higher than those of PK treatment,2.3,1.3 and 2.6 times higher than those of NK treatment,and were 16.4,8.8 and 22.4% higher than those of NP treatment,respectively.The soil pH was decreased and soil organic matter was increased in all treatments with increase in the time of sudangrass and ryegrass rotation system.The total soil N was increased in NP,NK and NPK treatments,while it was stable in PK treatment.The available P in NP,PK and NPK treatments was increased significantly,while it was stable in NK treatment.The slow releasing K and available K were increased significantly in NK and PK treatments,but decreased in NP and NPK treatments.The treatment with NPK combination was found to improve the yield of forage,nutrient uptake and soil fertility in sudangrass and ryegrass rotation system.

Selenium Alleviates Carbohydrate Metabolism and Nutrient Composition in Arsenic Stressed Rice Plants

This study reported the influence of selenium(Se)on carbohydrate composition and some related enzymes and nutrient compositions of arsenic(As)stressed rice plants.Rice plants of cultivar PR126 were grown on soil amended with As in a range of 25-100μmol/kg with and without 0.5 or 1.0 mg/kg Se.Total soluble sugars(TSS)and reducing sugars(RS)increased in leaves of As stressed plants at the tillering and grain filling stages whereas sucrose and starch contents showed the reverse trend.Se supplementation to As stressed plants further increased TSS and RS,and enhanced sucrose phosphate synthase activity in rice leaves,thus improving sucrose content and the tolerance to As stress of the plants.Se alone or in combination with As resulted in lower As accumulation in rice husk and grains,and the highest reduction was observed in Se applied at 1.0 mg/kg compared to the corresponding As treatments alone.As may limit the accumulations of Na,Mg,K,Ca,Fe,Zn and Mn in rice grains,which are essential for humans.Binary application of different combinations of As and Se protected the plants against As and increased the mineral content in rice grains.Addition of Se in As treated soil significantly alleviated As stress by enhancing grain yields compared to the corresponding As treatment.It is concluded that Se induced amelioration of the toxic impact of As in rice either by modulating carbohydrate composition and/or nutrient uptake is one of the mechanisms to alleviate As stress in plants.

Effect of cold plasma treatment on seedling growth and nutrient absorption of tomato

The effects of cold plasma(CP) treatment on seed germination, seedling growth, root morphology, and nutrient uptake of a tomato were investigated. The results showed that 80 W of CP treatment significantly increased tomato nitrogen(N) and phosphorus(P) absorption by12.7% and 19.1%, respectively. CP treatment significantly improved the germination potential of tomato seed by 11.1% and the germination rate by 13.8%. Seedling growth characteristics,including total dry weight, root dry weight, root shoot rate, and leaf area, significantly increased after 80 W of CP treatment. Root activity was increased by 15.7% with 80 W of CP treatment,and 12.6% with 100 W of CP treatment. CP treatment(80 W) markedly ameliorated tomato root morphology, and root length, surface area, and volume, which increased 21.3%, 23.6%, and29.0%, respectively. Our results suggested that CP treatment improved tomato N and P absorption by promoting the accumulation of shoot and root biomass, increasing the leaf area and root activity, and improving the length, surface area, and volume of root growth. Thus, CP treatment could be used in an ameliorative way to improve tomato nutrient absorption.

Effects of Microbial Inoculants on Nutrient Availability and Rice Yield

Under field conditions, an experiment was conducted to study the effects of ammonification bacteria, potassium bacteria and phosphorus bacteria on nutrient availability in soil and yield of rice in the cold region of China and compared to the conventional fertilization. Results showed that DF1P2 treatment （ammonifiers 1.5× 108 cfu· m2, phosphorus bacteria 1.5× 108 cfu. m2, and potassium bacteria 1.5× 108 cfu· m2） increased available nutrient concentrations in soil, increased the concentrations of N, P, and K in plant organs and increased the rice yield and was the most significantly among all the treatments. This treatment could be recommended as the best suitable biological fertilizer application rate for the rice production in the cold region of China.

Effect of Effluent from Biodigestion of Pre-Treated Rice Bran and Animal Manure on the Dry Matter Yield and Nutrient Uptake of <i>Amaranthus viridis</i>

The effect of effluents from biodigestion of pre-treated rice bran in combination with two types of animal manure on dry matter yield of Amarathus viridis was investigated using two pre-treatment methods: Soaking in ordinary distilled water and boiled in distilled water at 100°C. The pre-treated rice bran and animal manure were mixed (w/w basis) to give carbon to nitrogen ratio of 35:1 and 37:1 prior to loading into the digester to make eight different treatment combinations as follow: 1) Cow dung with no rice bran (NRB + CD);2) Raw rice bran + cow dung (RRB + CD);3) Soaked rice bran in ordinary distilled water + cow dung (SRB + CD);4) Boiled rice bran + cow dung (BRB + CD);5) Poultry manure with no rice bran (NRB + PM);6) Raw rice bran + poultry manure (RRB + PM);7) Soaked rice bran + poultry manure (SRB + PM);8) Boiled rice bran + poultry manure (BRB + PM). Samples of different treatment combinations were collected before digestion, both the samples and resultant effluents were subjected to elemental analysis using AAS. The effluents from the biodigestion of these combinations were applied at two rates (80 and 150 kg N ha-1) to 3 kg air-dried and sieved soil samples (0 - 20) cm in the greenhouse, control (0 kg N ha-1) and reference pot with NPK fertilizer at the 80 kg N ha-1 were arranged in a completely randomized design replicated three times. Amaranthus plants were introduced into each treated pot, left for four weeks before harvest, dry matter yields were recorded. Results of chemical analysis of raw materials and effluents obtained after biodigestion revealed the presence of all plant nutrients in both the raw materials and resultant effluents though the former had higher values in some nutrients than the effluent, for examples treatment combination of CD, the values for organic carbon (42.85%), Ca (3.41%) and Mg (0.61%) were higher than in the resultant effluent for CD, a similar trend was observed with other treatment combinations. Drastic reduction in heavy metal concentration was observed after digestion, Pb content in the raw materials for poultry manure reduced by 94.7% in the resultant effluent from BRB: PM thus making the effluent a better soil amendment. Raw chicken manure was richer in the nutrients needed for optimal crop growth however, raw cow dung had the highest. The amendment of effluent from boiled rice bran with poultry manure at 150 kg N ha-1 significantly increased the dry matter yield of Amaranthus viridis over control pots, NPK pots and all other amendments thus making it a good alternative to NPK fertilizer.

Yield of Wheat (<i>Triticum aestivum</i>) and Nutrient Uptake in Grain and Straw as Influenced by Some Macro (S &Mg) and Micro (B &Zn) Nutrients

A wheat variety BARI Gom 26 was cultivated with an objective of evaluating the effects of macro/secondary nutrients as S and Mg, and micro nutrients as B and Zn on yield, yield contributing traits and nutrient uptake status by the crop. The field experiment was con-ducted in the “North Eastern Barind Tract Soils” at Kushadaha, Nawabganj, Dinajpur, Bangladesh from November, 2014 to March, 2015. The surface soil was clay in texture, having pH 5.61, organic matter 1.58%, total N 0.10%, available P 7.03 ppm, exchangeable K 0.11 meq/100g, available S 2.57 ppm, exchangeable Mg 0.55 meq/100g, available Zn 1.30 ppm, available B 0.08 ppm. The experiment was designed with five treatments laid out in a randomized complete block design (RCBD) with three replications. The treatments were T1: NPK (control), T2: NPK + S, T3: NPK + S + Mg, T4: NPK + S + Mg + Zn and T5: NPK + S + Mg + Zn + B. All plots of wheat received 100 kg N/ha, 30 kg P/ha and 70 kg K/ha as basal dose. The secondary and micro nutrients doses were 15 kg S/ha, 6 kg Mg/ha, 2.5 kg Zn/ha and 1.5 kg B/ha. Results revealed that the plant height, tillers/hill, 1000-grain weight, yield of grain and straw, uptake of some specific nutrients in grain and straw were signifi-cantly influenced by all the treatments, though these treatments did not show any identical effect on spike length, content of P and Mg in wheat. Significantly highest amount of 1000-grain weight, yield of grain and straw weight of wheat were obtained in applying T2 treatment that employed the addition of S with recommended dose of NPK. Significant positive effects were also observed for the rest parameters in receiving the treatments composed of secondary and micronutrients (T3, T4, and T5). The highest concentration of nutrient uptake N, P, K and S in grain and straw of wheat were also obtained due to the application of T2 treatment. In the case of Mg, the maximum uptake was recorded in T4 where Mg was added as a component of this treatment. In contrast, the highest content of Zn and B were extracted in receiving the treatment T5 both for grain and straw. However, results suggested that T2 treatment comprising recommended dose of NPK with S might be economic and suitable as for better production of 1000-grain weight, yield of grain and straw, uptake of N, P, K and S in grain and straw of wheat cultivated in the North Eastern Barind Tract Soils of Bangladesh under winter condition. The treatment T5 would also be recommended in the context of addition of micronutrients.

Effects of phosphorus on nutrient uptake and rhizosphere acidification of soybean (G/ycine max L.)

Pot experiment was conducted to examine how application of KH2PO4 （0-165 mg·kg^-1 P） to affect nutrient ion uptake and rhizosphere acidification of soybean （Glycine max L.） grown in greenhouse for 90 days. When supplied of 82 and 165 mg·kg^-1 P, soybeans showed excessive poison. Under all kinds of P levels, the K, Ca, Na and Mg concents in plant tissues were as below order K was nodules 〉 roots 〉 pods 〉 shoots; Ca was shoots 〉 roots 〉 nodules 〉 pods; Na was roots 〉 nodules 〉 pods 〉 shoots and Mg was shoots 〉 nodules 〉 roots 〉 pods. K concent in plant tisssues had greater effect on rhizosphere acidification than other cations in this experiment irrespective of P supply, and was significantly negative to pH. Na concentration was significantly positive to pH. Excessive P supply induced rhizosphere acidification, pH decreased as P supply increased from 82 to 165 mg·kg^-1. Ash alkalinity in shoots and roots was significantly positively correlated with rhizosphere pH irrespective of P supply. All these results suggested that P supply affected nutrient uptake, induced ash alkalinity to increase and rhizosphere pH to decrease in soybean.

Biomass,nutrient uptake and fatty acid composition of Chlamydomonas sp.ICE-L in response to different nitrogen sources

Nitrogen removal from media by microalgae provides the potential benefit of producing lipids for biodiesel and biomass. However, research is limited on algal growth and biomass under different nitrogen sources and provides little insight in terms of biofuel production. We studied the influences of nitrogen sources on cell growth and lipid accumulation of Chlamydomonas sp. ICE-L, one of a promising oil rich micro algal species. Chlamydomonas sp.ICE-L grown in NH_4 Cl medium had maximum growth rate. While the highest dry biomass of 0.28 g/L was obtained in media containing NH_4NO_3, the highest lipid content of 0.21 g/g was achieved under nitrogendeficiency condition with a dry biomass of 0.24 g/L. In terms of total polyunsaturated fatty acids（PUFAs）production, NH_4NO_3 and NH_4 Cl media performed better than nitrogen-deficiency and KNO_3 media.Furthermore, NH_4NO_3 and NH_4 Cl media elucidated better results on C18：3 and C20：5 productions while KNO_3and-N conditions were better in C16：0, C18：1 and C18：2, comparatively.

Effects of dietary menthol-rich bioactive lipid compounds on zootechnical traits,blood variables and gastrointestinal function in growing sheep

Background:The present study aimed at investigating the influence of 90%menthol-containing plant bioactive lipid compounds(PBLC,essential oils)on growth performance,blood haematological and biochemical profile,and nutrient absorption in sheep.Twenty-four growing Suffolk sheep were allotted into three dietary treatments:Control(without PBLC),lower dose of PBLC(PBLC-L;80 mg/d)and higher dose of PBLC(PBLC-H;160 mg/d).Sheep in all groups were fed meadow hay ad libitum plus 600 g/d of concentrate pellets for 28 d.Results:Average daily gain was not affected by treatment.Feeding of PBLC increased hay and total feed intake per kg body weight(P<0.05).Counts of total leucocytes,lymphocytes and monocytes were not different among treatments.However,neutrophil count decreased(P<0.05)in PBLC-H with a similar trend in PBLC-L(P<0.10).Concentrations of glucose,bilirubin,triglycerides,cholesterol,urea and magnesium in serum were not different among sheep fed different doses of PBLC.However,serum calcium concentration tended to increase in PBLC-H(P<0.10)and serum concentrations of aspartate&asparagine(P<0.01)and glutamate&glutamine(P<0.05)increased linearly with increasing PBLC dose.In ruminal epithelia isolated from the rumen after killing,baseline conductance(Gt;P<0.05)and short-circuit current(Isc;P<0.01)increased in both PBLC groups.Ruminal uptakes of glucose and methionine in the presence of Na+were not affected by the dietary PBLC supplementation.In the absence of Na+,however,glucose and methionine uptakes increased(P<0.05)in PBLC-H.In the jejunum,Isc tended to increase in PBLC-H(P<0.10),but baseline Gtwas not affected.Intestinal uptakes of glucose and methionine were not influenced by PBLC in the presence or absence of Na+.Conclusion:The results suggest that menthol-rich PBLC increase feed intake,and passive ion and nutrient transport,the latter specifically in the rumen.They also increased serum concentrations of urea precursor amino acids and tended to increase serum calcium concentrations.Future studies will have to show whether some of these findings might be commonly linked to a stimulation of transient receptor potential(TRP)channels in the gastrointestinal tract.

Coinoculation of bioinoculants improve Acacia auriculiformis seedling growth and quality in a tropical Alfisol soil

We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.

Temporal patterns of storage and flux of N and P in young Teak plantations of tropical moist deciduous forest,India

Teak （Tectona grandis Linn. f.） ranks among the top five tropical hardwood species and is being promoted for use in plantations in its non-native range due to its high economic value. However, there is a general lack of data on ecosystem functioning of teak plantations. We aimed at understanding storage and flux of nutrients related to young plantations of teak. Cycling of nitrogen （N） and phosphorus （P） in a chronosequence of plantations （1, 5, 11, 18, 24 and 30 years） was studied in the Moist Deciduous Forest Region of North India with the objective of investigating the nutrient cycling pattern at younger age since the current trend of harvesting age of the species in several tropical countries is being drastically reduced for quick return from this high value crop. Standing state, nutrient uptake, nutrient return and nutrient retransloca-tion in these plantations were estimated by tree harvesting and chemical analysis methods. The range of total standing nutrient across all these plantations was 20.3 to 586.6 kg？ha-1 for N and 5.3 to 208.8 kg？ha-1 for P. Net uptake of N ranged from 19.4 to 88.9 kg？ha-1？a-1 and P from 3.8 to 18.1 kg？ha-1？a-1. Retranslocation of N and P among all the stands ranged from 8.7 to 48.0 kg？ha-1？a-1 and 0.01 to 3.5 kg？ha-1？a-1, respectively. Range of total nutrient return was 25.8 to 91.3 kg？ha-1？a-1 for N and 2.7 to 10.1 kg？ha-1？a-1 for P. N and P use efficiency was between 107.4 and 192.5 g dry organic matter （OM） g-1N, and 551.9 and 841.1 g OM g-1P, respec-tively. The turnover time ranged from 2.04-13.17 years for N and be-tween 2.40-22.66 years for P. Quantity of N and P in the soil nutrient pool ranged from 2566.8 to 4426.8 kg？ha-1 and 372 to 520 kg？ha-1, re-spectively. Storage and flux of components in different plant parts of different aged plantations were assessed and depicted in compartment models. Percentage storage in soil, litter and vegetation ranged from 82% to 99%, 0.6% to 2.4% and 0.5% to 15% for N, respectively, and from 63% to 98%, 0.5% to 2% and 1% to 35% for P, respectively. This infor-mation could be useful in managing external nutrient manipulation to crops of different ages for optimum biomass production or carbon se-questration.

Efficiency of seed bio-priming technique for healthy mungbean productivity under terminal drought stress

Recently, drought-induced damaging impact in reducing the crop growth and development is drastically ranked at the top under various abiotic stresses. And especially water stress at the reproductive growth stages termed as terminal drought has become a severe threat for mungbean productivity. To mitigate the drought stress condition, "bio-priming" has emerged as a newly agronomic and sustainable technique in improving the mungbean production. A 2-year field study during Kharif season 2017–2018 was conducted to investigate the efficacy of rhizobacteria seed priming in mungbean(AZRI mung-06), at Agronomic Research Area, Department of Agronomy, Bahauddin Zakariya University, Multan, Pakistan. The experiment comprised two factors containing FA(seed treatments, control(dry seeds), hydro-priming, silicon(Si)-priming, and bio-priming(mixture strains of Pseudomonas fluorescens+Rhizobium phaseoli)) and FB(irrigation water-regimes at various growth stages including leaf formation(L), stem elongation(S)+flowering(F)+pod formation(P) containing treatments are normal irrigation(I(L+S+F+P)) and terminal drought stress(I(F+P))). All the treatments were arranged in randomized complete block design under factorial design and were replicated thrice. Results indicated that the exposure of drought stress at flowering and pod formation stages hampered the morpho-physiological growth and yield of mungbean. Nevertheless, seed priming treatments particularly bio-priming were effective in alleviating the detrimental effects of drought stress. Bio-priming significantly increased the yield and yield components(seeds/plant, 1 000-grain weight and harvest index) of mungbean and regulated the activities/levels of antioxidants(superoxide dismutase, catalase, peroxidase, ascorbic acid, and total phenolics) under drought stress. Compared with the control, bio-priming increased the seed yield of mungbean by 8–12% under normal as well as drought stress conditions during both years of study. Bio-priming also improved the nutrient uptake behavior followed by Si-and hydro-priming treatments under terminal drought stress. The study emphasized the effectiveness of bio-priming as dual seed treatment method may be helpful for vigorous germination of mungbean production along with plant tolerance against terminal drought stress. Among the various treatments, plants treated with bio-priming technique compensated the grain yield due to having strong antioxidant defense system and better nutrient uptake behaviour under terminal drought stress. Economic analysis also concluded that bio-priming is the easiest, cost-effective, friendly, and sustainable approach for the maximization of the mungbean production.

Dynamics of fine root N,Pand K in high elevation forests of central Himalaya

Fine root nutrient dynamics were calculated for one year in three high elevation forests of Indian central Himalaya. In all sites, fine root nutrient concentrations varied with respect to forests and seasons. N concentration in fine roots was highest followed by K and P. In general, fine roots showed their highest nutrient concentrations during the rainy season and lowest in winter. Higher nutrient concentrations during the rainy season may be related to favorable moisture and temperature regimes which in turn results in increased plant growth activities. Present fine root nutrient amounts and nutrient uptake values decreased towards high elevations. In general, the highest amounts of nutrients in both live and dead fine roots were observed in September and the lowest in the month of June. Turnover rates of the nutrients in the fine roots also decreased with an increase in elevation.

Photosynthetic Behaviour and Mineral Nutrition of Tamarix gallica Cultivated Under Aluminum and NaCl Combined Stress

The lack of knowledge of plant tolerance and differential response to aluminum(Al)encouraged many researchers,in the last decade,to elucidate Al toxicity and tolerance mechanisms.The current study reported the impact of Al,a toxic element with negative effects on plant growth and development,in halophytic plant Tamarix gallica.Plants were subjected to different Al concentrations(0,200,500 and 800μM)with or without NaCl(200 mM)supplementation.Growth,photosynthesis and mineral content were assessed.Al stress had a significant decrease on shoots’biomass production between 19 to 41%,and a little variation on chlorophyll content and photosynthetic efficiency(Fo,Fm,Fv fluorescence’s and Fv/Fm).Furthermore,the Al-treatments did not affect significantly the content of potassium,calcium,and magnesium in different plant parts,whereas NaCl addition to the medium induced a decrease in these elements’concentrations.Our results have shown that T.gallica is able to accumulate the high levels of Al in shoots and roots,6288μg.g^(-1) DW and 7834μg.g^(-1) DW respectively.It is considered as a hyperaccumulator plant of Al.In addition,Na+contents in shoots and roots exceed 23000μg.g^(-1) DW.Therefore,T.gallica presents a high tolerance at the same time to Al and NaCl phytotoxicity,so it is interesting to use in phytoremediation programs.

Modelling the Relationship Between Summer Maize NPK Uptake and Yield on the Basis of Soil Fertility Indices

Quantitative estimation of fertilizer requirements can help to increase maize （Zea mays L.） yields and improve the fertilizer use efficiency. The model for the Quantitative Evaluation of the Fertility of Tropical Soils （QUEFTS） was calibrated for maize by use of soil fertility data and fertilizer trials at different sites of the Huang Huai Hai river plain in China. The QUEFTS model accounts for interactions between nitrogen （N）, phosphorus （P） and potassium （K）. It describes the effects of soil characteristics on maize yields in four steps： （1） assessment of the potential supply of N, P and K based on soil chemical data; （2） calculation of the actual uptake of N, P and K, in function of the potential supply as determined in step 1 ; （3） draft the yield ranges as a function of the actual uptake of N, P and K as determined in step 2; （4） calculation of the maize yield based on the three yield ranges established in step 3. Data of field experiments with different fertilization treatments of various regions in China during the years of 1985 to 1995 were used to calibrate the QUEFTS model for summer maize. In step 1 the N, P and K recovered from their amount applied were described by new equations. The minimum and maximum accumulated N, P and K （kg grain kg^-1） in summer maize were determined as （21-64）, （126-384） and （20-90）, respectively. The simulated yields were in good agreement with the observed ones. It was concluded that the calibrated and adjusted QUEFTS model could be useful to improve fertilizer recommendations for maize in the Huang Huai Hai plain of China.

Source of mycorrhizal inoculum influences growth of Faidherbia albida seedlings

Poor land use management and practice inhibit the growth and establishment of tree seedlings in dryland areas.We assessed arbuscular mycorrhizal fungi(AM)status of Faidherbia albida(Del.)A.Chev.trees grown on different land uses.We quantified the growth and nutrient uptake of F.albida seedlings inoculated with AM from different sources.These efforts were based on soil and fine root samples from the rhizosphere soils of F.albida trees.AM root colonization was determined using the gridline intersect method.Spores were extracted by the wet sieving and decanting method and identified to genus level.The seedling experiment had a completely randomized onefactorial design with four treatments and five replications.Faidherbida albida seedlings were grown in a greenhouse.All in situ F.albida trees were colonized by AM fungi.AM root colonization of F.albida trees was significantly higher(P<0.0086)in area exclosures than on lands used for grazing or cultivation.Spore abundance was significantly higher(P<0.0014)in area exclosures followed by cultivated land and grazing land.Glomus was the dominant genus in all land-uses.AM-inoculated F.albida seedlings grew better(P<0.05)than non-inoculated controls.Seedlings inoculated with AM from area exclosure had significantly(P<0.05)higher growth and nutrient uptake than those inoculated with AM from grazing and cultivated land.This emphasizes the importance of the native soil AM potential for better establishment of seedlings to achieve optimum plant growth improvement and assist in rehabilitation of degraded arid lands.