Phosphorus Use Efficiency Research Articles

Efficiency of phosphorus use in potato clones in two contrasting growing seasons

In Rio Grande do Sul the potato (Solanum tuberosum L.) can be grown in fall and spring. However, due to the contrasting weather conditions between these two seasons, which directly influence the growth of plants and the formation of tubers, it is necessary to identify potato clones adapted to such growing conditions. Thus, this work was carried out to characterize the efficiency of P use in potato clones grown in two contrasting seasons, in an off-soil growing system using sand as a substrate. The treatments were combined in a 2 x 4 x 2 factorial, consisting of two levels of P in the nutrient solution (2.32 and 23.2 mg P L-1), four potato clones (Asterix, Atlantic, SMIC 148-A and SMINIA 793101-3) and two growing seasons (spring and fall). The number of leaves and tubers per plant, the fresh and dry mass of the tubers, fresh mass of the shoot, P concentration in shoot and tubers, and efficiency of P use were determined. There is a difference between the potato clones in terms of the efficiency of P use in the spring and autumn crops of Rio Grande do Sul. Asterix and SMINIA 793101-3 clones show higher productivity in the spring growing and without P. restriction. SMIC 148-A clone was not influenced by the growing season, as long as the availability of P is not a limiting factor. Atlantic clone shows good production when grown in the fall, regardless of the level of P used

Growth, Rhizosphere Carboxylate Exudation, and Arbuscular Mycorrhizal Colonisation in Temperate Perennial Pasture Grasses Varied with Phosphorus Application

Phosphorus (P) fertiliser is applied regularly to the nutrient-poor sandy soils in southwestern Australia to elevate and/or maintain pasture production. This study aimed to characterise differential growth, root carboxylate exudation, and mycorrhizal responses in three temperate perennial pasture grasses at variable P supply. Tall fescue (Festuca arundinacea L. cv. Prosper), veldt grass (Ehrharta calycina Sm. cv. Mission), and tall wheatgrass (Thinopyrum ponticum L. cv. Dundas) with five P rates varying from 0 to 100 mg P kg−1 soil were evaluated in a controlled environment. Rhizosphere carboxylate exudation and mycorrhizal colonisation were assessed. Veldt grass produced the maximum shoot dry weight, highest agronomic phosphorus-use efficiency at low P supply, as well as the highest specific root length and shoot P content at all P rates. Across species, the maximum shoot weight was obtained at 20 and 50 mg P kg−1 soil, which differed significantly from the two lowest P rates (0 and 5 mg P kg−1 soil). Phosphorus application influenced carboxylate exudation, with plants exuding acetate only in the zero P treatment, and citrate and malonate in the P-supplemented treatments. In all three species, acetate and malonate were the major carboxylates exuded (37–51% of the total). Only tall wheatgrass released trans-aconitate. Citrate and malonate concentrations in the rhizosphere increased with P supply, suggesting their important role in P acquisition. Phosphorus applications reduced arbuscular mycorrhizal colonisation and increased root diameter as the P rate increased. Root carboxylate exudation in low-P soil played a role in mobilisation of P via P solubilisation, but the role of exuded carboxylate in soils well supplied with P might be diminished.

Supplemental application of phosphorus improves yield, quality and net returns of Gossypium hirsutum

Cotton is a white gold due to its high economic values. Phosphorus is an important constituent that is essential for seed development and yield. Efficient use of phosphorus plays a significant role to achieve quality production in form of yield to overcome the problems. A field study comprised of four phosphorus levels viz. (P0= 0 kgha-1, P1 =50 kgha-1, P2 =100 kg ha-1 P3 =150 kg ha-1) and cultivars viz CIM-598, MNH-886, CIM-616, CIM-612, FH-LALAZAR during 2015 and 2016. Application of phosphorous significantly improved quality and yield in terms of plant height (161.33 cm), bolls number plant-1 (31.667), number of nodes plant-1 (49.000), boll weight (2.200 g), seed cotton harvest (3481.3 %), seed cotton yield (2928.3 kg ha-1), seed lint yield (56.667 kg ha-1), biological yield (0.960 kg ha-1), and ginning out turn (0.0227 %). Significant increase was observed for leaf area index (0.980 m-2), crop growth rate (1.416 g m-2 day-1), net assimilation rate (1.480 g m-2 day-1), leaf area duration (871.33), phosphorus concentration (0.270), fiber uniformity (70.667), staple length (47.500 mm), fiber strength (33.500 tppsi) and micronair (5.166 µg inch-1). Phosphorus spray of 150 kg ha-1 is more suitable for greater cotton production. Keywords: Cotton; Cotton quality; Economic benefits; Fiber uniformity; Phosphorus http://dx.doi.org/10.19045/bspab.2020.90274

Interaction of liming and long-term fertilization increased crop yield and phosphorus use efficiency (PUE) through mediating exchangeable cations in acidic soil under wheat\u2013maize cropping system

Low phosphorus use efficiency (PUE) is one of the main problems of acidic soil that limit the crop growth. Therefore, in the present study, we investigated the response of crop yield and PUE to the long-term application of fertilizers and quicklime (CaO) in the acidic soil under wheat–maize rotation system. Treatments included, CK (no fertilization), NP (inorganic nitrogen and P fertilization), NPK (inorganic N, P and potassium fertilization), NPKS (NPK + straw return), NPCa (NP + lime), NPKCa (NPK + lime) and NPKSCa (NPKS + lime). Results showed that, fertilizer without lime treatments, significantly (p ≤ 0.05) decreased soil pH and crop yield, compared to the fertilizer with lime treatments during the period of 2012–2018. Average among years, compared to the CK treatment, wheat grain yield increased by 138%, 213%, 198%, 547%, 688% and 626%, respectively and maize yield increased by 687%, 1887%, 1651%, 2605%, 5047% and 5077%, respectively, under the NP, NPK, NPKS, NPCa, NPKCa and NPKSCa treatments. Lime application significantly increased soil exchangeable base cations (Ca2+ and Mg2+) and decreased Al3+ cation. Compared to the NP treatment, phosphorus use efficiency (PUE) increased by 220%, 212%, 409%, 807% and 795%, respectively, under the NPK, NPKS, NPCa, NPKCa and NPKSCa treatments. Soil pH showed significant negative relationship with exchangeable Al3+ and soil total N. While, soil pH showed significant (p ≤ 0.05) positive relationship with exchangeable Ca2+, PUE and annual crop yield. PUE was highly negatively correlated with soil exchangeable Al3+. In addition, soil exchangeable Ca2+, pH, exchangeable Al3+ and available N were the most influencing factors of crop yield. Therefore, we concluded that lime application is an effective strategy to mitigate soil acidification and to increase PUE through increasing exchangeable base cations and reducing the acidic cations for high crop yield in acidic soil.

Field pea (Pisum sativum L.) shows genetic variation in phosphorus use efficiency in different P environments

Field pea is important to agriculture as a nutritionally dense legume, able to fix nitrogen from the atmosphere and supply it back to the soil. However, field pea requires more phosphorus (P) than other crops. Identifying field pea cultivars with high phosphorus use efficiency (PUE) is highly desirable for organic pulse crop biofortification. This study identified field pea accessions with high PUE by determining (1) the variation in P remobilization rate, (2) correlations between P and phytic acid (PA), and (3) broad-sense heritability estimates of P concentrations. Fifty field pea accessions were grown in a completely randomized design in a greenhouse with two replicates under normal (7551 ppm) and reduced (4459 ppm) P fertilizer conditions and harvested at two time points (mid-pod and full-pod). P concentrations ranged from 332 to 9520 ppm under normal P and from 83 to 8473 ppm under reduced P conditions across all tissues and both time points. Field pea accessions showed variation in remobilization rates, with PI 125840 and PI 137119 increasing remobilization of P under normal P conditions. Field pea accessions PI 411142 and PI 413683 increased P remobilization under the reduced P treatment. No correlation was evident between tissue P concentration and seed PA concentration (8–61 ppm). Finally, seed P concentration under limited P conditions was highly heritable (H2 = 0.85), as was mid-pod lower leaf P concentrations under normal P conditions (H2 = 0.81). In conclusion, breeding for PUE in field pea is possible by selecting for higher P remobilization accessions in low P soils with genetic and location sourcing.

A genome-wide association study reveals the quantitative trait locus and candidate genes that regulate phosphate efficiency in a Vietnamese rice collection.

The crucial role of phosphate (Pi) for plant alongside the expected depletion of non-renewable phosphate rock have created an urgent need for phosphate-efficient rice varieties. In this study, 157 greenhouse-grown Vietnamese rice landraces were treated under Pi-deficient conditions to discover the genotypic variation among biochemical traits, including relative efficiency of phosphorus use (REP), relative root to shoot weight ratio (RRSR), relative physiological phosphate use efficiency (RPPUE), and relative phosphate uptake efficiency (RPUpE). Plants were grown in Yoshida nutrient media with either a full (320μM) or a low Pi supply (10μM) over six weeks. This genome-wide association study led to the discovery of 31 significant single nucleotide polymorphisms, 18 quantitative trait loci (QTLs), and 85 candidate genes. A common QTL named qRPUUE9.16 was found among thethree investigated traits. Some interesting candidate genes, such as PLASMA MEMBRANE PROTEIN1 (OsPM1), CALMODULIN-RELATED CALCIUM SENSOR PROTEIN 15 (OsCML15), phosphatases 2C (PP2C), STRESS-ACTIVATED PROTEIN KINASE (OsSAPK2), and GLYCEROPHOSPHORYL DIESTER PHOSPHODIESTERASES (GDPD13), were found strongly correlated to the Pi starvation. RNA sequencing transcriptomes revealed that 45 out of 85 candidate genes were significantly regulated under Pi starvation. Furthermore, nearly two-thirds of genotypes did not possess the OsPsTOL1 gene; however, no significant difference was observed in response to Pi deficiency between genotypes with or without this gene, suggesting that other QTLs in rice may resist Pi starvation. These results provide new information on the genetics of nutrient use efficiency in rice and may potentially assist with developing more phosphate-efficient rice plants.

Genome-Wide Association Analysis for Phosphorus Use Efficiency Traits in Mungbean (Vigna radiata L. Wilczek) Using Genotyping by Sequencing Approach.

Mungbean (Vigna radiata L. Wilczek) is an annual grain legume crop affected by low availability of phosphorus. Phosphorus deficiency mainly affects the growth and development of plants along with changes in root morphology and increase in root-to-shoot ratio. Deciphering the genetic basis of phosphorus use efficiency (PUE) traits can benefit our understanding of mungbean tolerance to low-phosphorus condition. To address this issue, 144 diverse mungbean genotypes were evaluated for 12 PUE traits under hydroponics with optimum- and low-phosphorus levels. The broad sense heritability of traits ranged from 0.63 to 0.92 and 0.58 to 0.92 under optimum- and low-phosphorus conditions, respectively. This study, reports for the first time such a large number of genome wide Single nucleotide polymorphisms (SNPs) (76,160) in mungbean. Further, genome wide association study was conducted using 55,634 SNPs obtained by genotyping-by-sequencing method. The results indicated that total 136 SNPs shared by both GLM and MLM models were associated with tested PUE traits under different phosphorus regimes. We have identified SNPs with highest p value (–log10(p)) for some traits like, TLA and RDW with p value (–log10(p)) of more than 6.0 at LP/OP and OP condition. We have identified nine SNPs (three for TLA and six for RDW trait) which was found to be present in chromosomes 8, 4, and 7. One SNP present in Vradi07g06230 gene contains zinc finger CCCH domain. In total, 71 protein coding genes were identified, of which 13 genes were found to be putative candidate genes controlling PUE by regulating nutrient uptake and root architectural development pathways in mungbean. Moreover, we identified three potential candidate genes VRADI11G08340, VRADI01G05520, and VRADI04G10750 with missense SNPs in coding sequence region, which results in significant variation in protein structure at tertiary level. The identified SNPs and candidate genes provide the essential information for genetic studies and marker-assisted breeding program for improving low-phosphorus tolerance in mungbean.

Delayed greening in phosphorus-efficient Hakea prostrata (Proteaceae) is a photoprotective and nutrient-saving strategy.

Hakea prostrata R.Br. (Proteaceae) shows a 'delayed greening' strategy of leaf development characterised by reddish young leaves that become green as they mature. This trait may contribute to efficient use of phosphorus (P) during leaf development by first investing P in the development of leaf structure followed by maturation of the photosynthetic machinery. In this study, we investigated the properties of delayed greening in a highly P-efficient species to enhance our understanding of the ecological significance of this trait as a nutrient-saving and photoprotective strategy. In glasshouse-grown plants, we assessed foliar pigments, fatty acids and nutrient composition across five leaf developmental stages. Young leaves had higher concentrations of anthocyanin, P, nitrogen (N), copper (Cu), xanthophyll-cycle pigments and saturated fatty acids than mature leaves. As leaves developed, the concentration of anthocyanins decreased, whereas that of chlorophyll and the double bond index of fatty acids increased. In mature leaves, ~60% of the fatty acids was α-linolenic acid (C18:3 n-3). Mature leaves also had higher concentrations of aluminium (Al), calcium (Ca) and manganese (Mn) than young leaves. We conclude that delayed greening in H. prostrata is a strategy that saves P as well as N and Cu through sequential allocation of these resources, first to cell production and structural development, and then to supplement chloroplast development. This strategy also protects young leaves against photodamage and oxidative stress during leaf expansion under high-light conditions.

Long-term effects of 7-year warming experiment in the field on leaf hydraulic and economic traits of subtropical tree species.

Rising temperature associated with climate change may have substantial impacts on forest tree functions. We conducted a 7-year warming experiment in subtropical China by translocating important native forest tree species (Machilas breviflora, Syzygium rehderianum, Schima superba and Itea chinensis) from cooler high-elevation sites (600m) to 1-2°C warmer low-elevation sites (300 and 30m) to investigate warming effects on leaf hydraulic and economic traits. Here, we report data from the last 3years (Years 5-7) of the experiment. Warming increased leaf hydraulic conductance of S. superba to meet the higher evaporative demand. M. breviflora (300m), S. rehderianum, S. superba and I. chinensis (300 and 30m) exhibited higher area-based and mass-based maximum photosynthetic rates (Aa and Am , respectively) related to increasing stomatal conductance (gs ) and stomatal density in the wet season, which led to rapid growth; however, we observed decreased growth of M. breviflora at 30m due to lower stomatal density and decreased Aa in the wet season. Warming increased photosynthetic nitrogen-use efficiency and photosynthetic phosphorus-use efficiency, but reduced leaf dry mass per unit area due to lower leaf thickness, suggesting that these tree species allocated more resources into upregulating photosynthesis rather than into structural investment. Our findings highlight that there was trait variation in the capacity of trees to acclimate to warmer temperatures such that I. chinensis may benefit from warming, but S. superba may be negatively influenced by warming in future climates.

Phosphorus Nutrient Management through Synchronization of Application Methods and Rates in Wheat and Maize Crops.

Management of inorganic fertilizer is very important to obtain maximum crop yield and improved nutrient use efficiency in cereal crops. Fixation of phosphatic fertilizers in alkaline soils due to calcareousness is one of the major hurdles. It induces phosphorus nutritional stress that can decrease the yield of maize and wheat. Selection of a suitable application method and proper stage of crop for phosphorus (P) fertilizer has prime importance in better uptake of P and crop production. Among different application methods, soil and foliar application are widely adopted. In wheat and maize, knee height + tasseling and stem elongation + booting are critical stages towards P deficiency. That is why field trials were conducted to evaluate the supplemental effect of foliar P on maize and wheat yields. For that, 144 mM KH2PO4 was applied as foliar at knee height + tasseling and stem elongation + boot stages in maize and wheat, respectively. Soil application of 0, 20, 40 and 60 kg P ha−1 was done through broadcast and band methods. Results showed that foliar spray of 144 mM KH2PO4 at knee height + tasseling and stem elongation + boot stages in wheat and maize significantly enhanced grains yield and phosphorus use efficiency (PUE) where P was applied as banding or broadcast at the time of sowing. A significant decreasing trend in response to increasing soil P levels validated the efficacious role and suitability of foliar P. In conclusion, the use of P as foliar at knee height + tasseling and stem elongation + boot stages is an efficacious way to manage P fertilizer.

Polymer-Paraburkholderia phytofirmans PsJN Coated Diammonium Phosphate Enhanced Microbial Survival, Phosphorous Use Efficiency, and Production of Wheat

Low bioavailability of phosphorus (P) in alkaline/calcareous soils leads to low yields due to its precipitation/fixation with calcium (Ca). An effective method to enhance phosphorus use efficiency (PUE) and its availability to plants is the application of alginate bioaugmented coated di-ammonium phosphate (DAP). In this study, the pre-isolated P solubilizing Paraburkholderia phytofirmans (PsJN) coated with different concentrations of polymer (alginate) on DAP with and without carbon source was tested in incubation, pot, and field experiments to investigate microbial survival, Olsen P release, and its availability to plants. Results indicated that the maximum recovery of PsJN loaded on alginate at 30 days incubation with and without carbon source was 199 × 1010 and 82 × 106 CFU mL−1 respectively. Application of alginate bioaugmented DAP released 962 mg kg−1 Olsen P after 60 days of incubation compared to 280 and 370 mg kg−1 Olsen P released by uncoated and simple alginate coated DAP, respectively. Results from pot trial revealed that application of 100% alginate bioaugmented DAP increased 26% plant height, 31% photosynthetic rate, 55% grain yield, and 6 × 105 CFU g−1 root bacterial population, compared to uncoated DAP. Field trial results indicated that 22% grain yield, 14% straw yield, and 44% agronomy P efficiency were increased by applying 100% alginate bioaugmented DAP compared to uncoated DAP. This new approach resulted in controlled release of P from coated DAP that not only reduced phosphorus fixation but also enhanced the bioavailability of P to plants.

Effect of Phosphorus on Yield, Nutrient Acquisition and Use Efficiency of Groundnut in West Bengal, India

Background: Phosphorus is the crucial element to enhance yields as well bio-chemical properties namely protein and oil content in groundnut. Buildup of insoluble phosphates and chemical fixation in soil reduces phosphorus consumption ability in plants. Phosphorus use efficiency (PUE) can be increased with higher levels of phosphorus rate. The study was framed to investigate the effect of phosphorus fertilization on yield, nutrient acquisition, use efficiency and bio-chemical compositions of groundnut. Methods: The experiment was conducted in summer seasons of 2016 and 2017, using split plot design with three varieties (‘JL-24’, ‘Gangapuri’, ‘TAG-24’) in main plot and four fertilization levels (0, 40, 60, 80kg P2O5 ha-1) in sub plots. Result: The study revealed that pod yield enhanced significantly by 15.4%, 27.3% and 39.9% with increase in fertilization rates from 40kg to 80kg ha-1 compare to unfertilized plots. Protein and oil content showed a positive response with phosphorus application. Agronomic efficiency, recovery efficiency and utilization efficiency were also increased with phosphorus rates, whereas, partial factor productivity, agro-physiological efficiency and physiological efficiency had decreasing trends. ‘Gangapuri’ gave higher pod yield (1.80t ha-1), protein (24.27%) and oil (45.41%) content than other selected varieties. Enhanced phosphorus rate also increases nutrient uptake in groundnut.

Agronomic Performance of Corn Cultivars as a Function of Phosphorus Use

Aims: The research was carried out to evaluate the agronomic performance of corn cultivars in contrasting phosphorus environments in the state of Pará, Brazil.
 Study Design: The experimental design was randomized blocks with ten treatments and three replications. The treatments were composed of ten cultivars: AG 1051, AG 8088PRO2, BR 206, BRS 3046, PR 27D28, 2B655PW, AL BANDEIRANTE, ANHEMBI, CATIVERDE 02 and ORION
 Place and Duration of Study: In the 2017/18 crop, two competition trials of corn cultivars were carried out at Sítio Vitória, municipality of Santa Maria das Barreiras, state Pará, Brazil.
 Methodology: Two competition trials of corn (Zea mays L.) cultivars were carried out under contracting conditions of phosphorus: high P (100 kg ha-1 of P2O5) and low P (50 kg ha-1 of P2O5), using simple superphosphate (18% P2O5) as the source. The agronomic efficiency of phosphorus use was obtained by the difference between grain yield in both levels, divided by the difference between doses. The variables evaluated were: ear height, plant height, ear diameter, number of rows per year, number of grains per rows and grain yield.
 Results: The mean grain yield of the cultivars ranged from 5,446 kg ha-1 (low P) to 11,486 kg ha-1 (high P), and the means of all cultivars were higher in high P. The means agronomic efficiency ranged from 25.1 kg kg-1 (AL BANDEIRANTE) to 96.6 kg kg-1 (AG 1051).
 Conclusion: The highest phosphorus dose (100 kg ha-1 of P2O5) resulted in higher values in the variables studied. The cultivars that stood out the most, under high and low phosphorus, were AG 8088PRO2, AG 1051 and BRS 3046, the last two being agronomically efficient.

Towards an integrated nutrient management in crop species to improve nitrogen and phosphorus use efficiencies of Chaohu Watershed

Low nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE) of crop farming has been causing serious environmental consequences. Here, we established a NUECF (nutrient use efficiency of crop farming) model with substance flow analysis (SFA) method to examine NUE and PUE of cultivating nine main crops in Chaohu Watershed in 2015. We collected data mainly from questionnaires, interview, literature, and governmental statistical yearbooks. We found that the total NUE and the total PUE were low, bellowing 12.3% and 5.2%, respectively. The nutrient inputs especially large-scale livestock manure, domestic livestock manure, and chemical fertilizers far exceeded the crop products. Different crops also showed the various patterns of nutrient use efficiencies. Rice consumed the largest nutrient inputs (807 kg N ha−1 and 367 kg P ha−1) and contributed the lowest nutrient use efficiencies (NUE: 5.8%, PUE: 2.7%). This was mainly resulted from its large fertilizer application intensity and the largest cultivated area. Rapeseed, vegetable, and wheat also contributed the great nutrient inputs and low nutrient use efficiencies, due to the similar reasons. Concerning the various patterns of fertilizer-application and cultivated areas of these crops, we analyzed six scenarios focusing on rice, wheat, rapeseed, and vegetable for 2030 and 2050 to explore an efficient nutrient management. We selected the four key factors including application intensity of chemical fertilizer, application rate of domestic livestock manure, application rate of large-scale livestock manure, and cultivated area to design the scenarios. The scenario results showed that though current policy of controlling chemical fertilizer application is a good start to manage nutrient, we have to enhance an integrated nutrient management, including reducing chemical fertilizers on specific crops, enlarging livestock manure, and controlling cultivated areas of specific crops. With the integrated nutrient management, we can expect the nutrient inputs to reduced by 26% and hence improve the nutrient use efficiencies efficiently from 2015 to 2050. The study managed the nutrients from examining nutrient use efficiencies among different crops, and could provide an effective way to mitigate the environmental problems from crop farming.

Studies on effect of phosphorus levels, time of it’s application along with arbuscular mycorrhiza on yield, quality and phosphorus use efficiency in sugarcane

A field experiment was conducted in clayey textured soil at N.M. College of Agriculture, Research farm, Navsari Agril., University, Navsari, Gujarat during 2017-18 and 2018-19 with the view to evaluate an appropriate phosphorus level (100 and 75% of RD of P2O5), determining the time of P2O5 application (Basal and 50-50% Split), with and without use of biofertilizer as arbuscular mycorrhiza (AM) on the yield, quality and Phosphorus use efficiency (PUE) of sugarcane. The pooled data of two seasons indicated that sugarcane crop responded significantly with phosphorus management. Significantly highest yield attributes, cane, green top and quality of juice were recorded with 100 percent RD of P2O5, splitting of phosphorus and with the use of AM in Sugarcane. Similar significant results in terms of P content in juice and sugar yield were recorded. The Agronomic phosphorus use efficiency and partial factor productivity were enhanced significantly with splitting of P2O5 and AM in sugarcane.

Improving Tuber Yield and Phosphorus Use Efficiency Using Split Phosphorus Application to Potatoes in Inner Mongolia

Increasingly, phosphorus (P) fertilizer is being applied in Inner Mongolia of China to overcome the problem of insolubility of phosphorus in calcareous soil and meet the growth demand of potato plants. As a result, phosphorus use efficiency (PUE) in potatoes decreases continually. In this four-year study in sandy soils, drip fertigating potatoes with phosphorus during the growth season improved phosphorus uptake, plant growth, tuber yield, and PUE. Results show that relative to a single phosphorus application, using a split phosphorus application regime through drip irrigation significantly increased the leaf area index (LAI) and phosphorus uptake rate in the mid and late growth stages of potatoes, and enhanced potato yield and PUE. We concluded that split phosphorus application has the potential to benefit sustainable potato production in Inner Mongolia of China.

Strategic timing and rate of phosphorus fertilization improves phosphorus-use efficiency in two contrasting cultivars of subirrigated greenhouse-grown chrysanthemum

Greenhouse floriculture operations pose significant environmental risk due to extensive inputs of fertilizer, especially nitrogen and phosphorus (P). Recent evidence shows that the use efficiency for nitrogen or sulphur is markedly improved in subirrigated potted chrysanthemums (Chrysanthemum morifolium Ramat.) by supplying a moderate level of the nutrient during vegetative growth, and removing the entire nutrient suite at the onset of reproductive growth, without adverse effects on plant quality. Here, two split-plot experiments were conducted with subirrigated, potted, disbudded chrysanthemums grown in a peat:perlite mixture under greenhouse conditions (high- or low-ambient light) with inorganic orthophosphate (Pi) treatment (2.6 mmol L−1 Pi supplied during the vegetative and reproductive stages, and 2.6, 1.95, or 1.3 mmol L−1 Pi supplied during the vegetative stage only) as the main plot and cultivar (‘Olympia’ and ‘Covington’) as the subplot. Market quality plants with sufficient tissue P were produced even when Pi delivery was reduced by approximately 75% over the crop cycle, compared with industry standards. The primary mechanism for sustaining plant growth with decreasing Pi delivery was improved acquisition or uptake efficiency, although some changes in internal P-utilization efficiency were evident, including the remobilization of both organic P and Pi during inflorescence development. Differences in biomass yields, tissue P concentrations, content-based P-use efficiency (PUEC = mg shoot dry mass/mg shoot P content) with constant Pi acquisition, and uptake- versus remobilization-based P supply for inflorescence growth established that ‘Olympia’ has a greater P-utilization efficiency than ‘Covington’. This modified subirrigation practice could contribute significantly to low-input production of floricultural crops.

Optimizing the nutritional quality and phosphorus use efficiency of alfalfa under drip irrigation with nitrogen and phosphorus fertilization

AbstractAppropriate fertilization is an important management practice for optimizing the nutritional quality and increasing the phosphorus use efficiency (PUE) of field‐grown alfalfa (Medicago sativa L.). A 2‐yr field experiment in 2017 and 2018 in Xinjiang, China, involving fertilization with different amounts of N (0, 105, and 210 kg ha−1, referred to as N0, N1, and N2, respectively) and P (0, 50, 100, and 150 kg ha−1, referred to as P0, P1, P2, and P3, respectively) was established and resulted in the production of high‐quality alfalfa under drip irrigation. The crude protein (CP) content in the N1 treatment was greater than that in the N2 treatment under the P0, P2, and P3 treatments. Compared with that in the N1P0 and N2P3 treatments, the relative feed value (RFV) in the N1P2 treatment increased by 9−21% and 8−18%, respectively. The annual total CP yield in the N1P2 treatment was the greatest. Compared with that in the N1P3 treatment, the total PUE in the N1P2 treatment increased by 76.69−99.69%. At each clipping, the CP yield and PUE of alfalfa were significantly different between the N and P treatments. Therefore, we conclude that when N was applied at 105 kg ha−1 and P was applied at 100 kg ha−1, alfalfa presented the greatest nutritional quality and PUE under drip irrigation.

Coating phosphorus fertilizer with renewable natural polymers

Low phosphorus use efficiency (PUE) is one of the major reasons of poor production worldwide. Among the various approaches used to enhance PUE, polymer coated fertilizers are relatively a new concept. Its main advantages are that they dissolve slowly and release nutrients to plants gradually during the growing season. Keeping this in view, a study was performed in the laboratory to evaluate polymers coated monoammonium phosphate (MAP) to enhance PUE. Commercial MAP and MAP coated with biodegradable polymers with Krafit black liquor (BL) and cellulose acetate (CA) in the concentration (0.5, 1.0, 2.0 wt % coating). The effectiveness of these coatings was assessed by the electrical conductivity (EC) and phosphorus release (PR) in a kinetic experiment. The kinetic study was carried out in a controlled environment (± 25 °C), following the release pattern of P from 1.5 g of fertilizer in 50 mL of H2O, with and without the coatings. The objective of this work was to study different lignin-based coatings and the phosphorus release behavior of the resulting fertilizer. EC showed to be an effective method of indirect analysis of P releasing from coated MAP. The BL coating presented better results than the CA in terms of controlling the release of P, and the higher the coating ratio (1.0 and 2.0 %) the slower the release of P.

Effect of lime, organic matter and boron on the use efficiency of phosphorus in lentil (Lens culinaris L.)

An experiment with lentil (Lens culinaries L.) was conducted at the terai situation of West Bengal (India) under different combination of phosphorus, boron and farm yard manure (FYM). The soil was acidic (pH-5.35) in reaction with sandy -loam in texture and hence, liming material was applied to find out the use efficiency of the phosphorus (P) in determining the yield potential of the crop (lentil). The maximum grain yield of lentil was 13.93 qha-1 at the lime- treated soil compared to the untreated control (6.63qha-1). The seed yield was increased from 9.64 to 13.85 qha-1 with the increasing level of P. The effect of P was relatively lower in a soil not treated with lime. The Physiological Harvest Index (PHI) was higher (56.67) when P @ 60 kgha-1 was applied irrespective of any treatment combinations and was minimum (54.95) at the lower rate of P (30 kgha-1) application. The maximum Agronomic efficiency (AE) was 18.3 and that of Physiological Efficiency (PE) was 85.16 at the lower rate of P (30 kgha-1) application. Hence, application of lime in soil with organic matter and B can improve the use efficiency of P for lentil in an acidic soil of a region.