Nutrient Uptake Efficiency Research Articles

Nutrient uptake and use efficiency of onion seed yield as influenced by nitrogen and phosphorus fertilization

The experiment was conducted at Kulumsa, South East Ethiopia, using four levels of nitrogen (N) (0, 50,100 and 150 kg N ha−1) and four levels of phosphorus (P) (0, 35, 70 and 105 kg P2O5 ha−1) fertilizers arranged in 4 × 4 factorial arrangements in randomized complete block design with three replications. The available P was increased after harvest due to the application of N and P fertilizer at the rates of 100 or 150 kg N ha−1 and 70 or 105 kg P2O5 ha−1. More specifically, nutrients concentration and nutrient uptake were significantly (p < .01) varied among treatment combinations and nutrient use efficiency was declined by increasing N and P after optimum rates. The higher physiological efficiency of N (53.47 kg kg−1) and P (580.41 kg kg−1) and the highest apparent recovery of N (19.62%) and P (2.47%) was recorded from application of 50 kg N ha−1 and P at 70 kg P2O5 ha−1 and the highest agronomic efficiency of N (10.78 kg kg−1) and P (15.25 kg kg−1) was recorded from N at the rate of 50 kg N ha−1 and P at 35 kg P2O5 ha−1, respectively. The combination of N at 100 kg N ha−1 and P at 70 kg P2O5 ha−1 was promising combination that generated highest net benefit 488,878.5 ETB (Ethiopian birr) ha−1 with the highest marginal rate of return (36638%) and gave the highest seed yield (1858.82 kg ha−1) with yield increment of about 57.72% over the control.

Influence of seed size on the growth, productivity, and water use efficiency of bread wheat planted by different methods

ABSTRACT In this two-year field study, influence of seed size on the growth and performance of wheat sown under different sowing methods was evaluated. The experiment comprised of three seed size classes viz. bold size, medium size and small size and five sowing methods, (1) broadcast, (2) line sowing, (3) no-till sowing, (4) bed planting, and (5) broadcast augmented with furrows. Among sowing methods highest yield (4.59 and 4.40 t ha−1) and water productivity (2.02 and 1.92 kg m−3) were recorded in bed planting. During both years, yield of bed planted wheat was significantly higher (5–29%) compared with other sowing methods. However, less cost of production in no-till sowing resulted in higher resource use efficiency (0.91, 0.73) than other wheat planting methods. Among seed size classes, the crop raised from bold seeds performed better for weed competitiveness, nutrient uptake, and resource use efficiency (0.79 and 0.63). The yield of crop raised from bold seeds was the best in all sowing methods except in broadcast where medium sized seeds performed better for yield (4.19, 4.35 t ha−1), nutrient uptake and resource use efficiency (0.73, 0.63). Therefore, planting bold wheat seeds on beds may help harvest better productivity and profitability.

PENGARUH PEMBERIAN PUPUK ORGANIK CAIR LIMBAH IKAN TERHADAP PERTUMBUHAN DAN HASIL TANAMAN TOMAT (Lycopersicum esculentum Mill)

Tujuan dari penelitian ini adalah untuk mengetahui pengaruh pemberian pupuk organik cair dari limbah ikan nila dapat meningkatkan pertumbuhan dan hasil tanaman tomat (Lycopersicon esculentum mill). Metode penelitian ini disusun dengan menggunakan Rancangan Acak Lengkap (RAL) satu faktor dengan 3 ulangan dan di dalam penelitian ini semua unit penelitian diletakkan secara acak (random). Faktor nya adalah pupuk organik cair dengan konsentrasi yang terdiri dari 3 level, dengan rincian berikut : P1 : pupuk 3,5% = 35 ml pupuk dalam 1000 ml, P2 : pupuk 4% = 40 ml pupuk dalam 1000 ml, P3 : pupuk 4,5% = 45 ml pupuk dalam 1000 ml. Pupuk organik cair limbah ikan berpengaruh terhadap pertumbuhan dan hasil tanaman tomat disebabkan oleh beberapa faktor yaitu : a) Mikroorganisme : Mikroorganisme tanah memiliki kegunaan untuk meningkatkan efisiensi serapan hara oleh akar tanaman, b) Mekanisme serapan unsur hara : Unsur hara yang diserap melalui akar dan melalui daun.

Effects of grafting on fruit yield and leaf nutrient contents of pepper (Capsicum annuum L.) inbred lines

A field experiment was conducted to investigate the rootstock effects on the fruit and seed yield and leaf nutrient contents of pepper, four pepper inbred lines (ER? 1227 and ER? 462: Long fruited green pepper type; 21 H-1-2 and 33 H-3-1: Bell shaped pepper type) were grafted onto two pepper rootstock genotypes (46 KB F1 and Scarface F1). The non-grafted scion genotypes were used as control plants. Between grafted and non-grafted plants significant (p&lt;0.001) differences were found in fruit yield, dry matter, diameter, length and fruit number, seed yield, thousand seed weight and leaf P, K, Ca, Mg, Mn and Zn contents. Among the graft combinations, significantly higher fruit yield, dry matter, length of long fruited green pepper genotypes, leaf K content was observed when ?ER? 1227? grafted onto ?Scarface? rootstock; significantly higher Ca and Mn contents were recorded when ?ER? 462? grafted onto ?Scarface? rootstocks. Whereas, significantly highest fruit number and diameter of long fruited green pepper genotypes was recorded at the non-grafted plants of ?ER? 1227?. Overall, the pepper rootstock genotype ?Scarface? showed a better performance for fruit yield, dry matter, length of long fruited green pepper genotypes, fruit diameter of bell shaped pepper genotypes, K, Ca, Mg and Mn contents in leaf tissue, thousand seed weight in different graft combinations as compared to non-grafted pepper plants. All these suggest that the powerful rootstocks, which might be characterized by an efficient nutrient uptake, play a major role in improvement of plant growth performance, fruit, and seed yield.

Nitrogen affecting switchgrass yield, nitrogen removal, and use efficiency

AbstractBest management practices for switchgrass (Panicum virgatum L.) fertilization in the production of biofuel feedstock and forage hay are variable depending on climate, harvest timing, and variety. A study of N fertilization was conducted to evaluate the yield response, nutrient removal, and nitrogen use efficiency (NUE) in 12 yr old switchgrass stands in Stillwater, OK. Seven rates of N fertilizer were applied ranging from 0 to 235.2 kg N ha−1 for 3 consecutive years (2008, 2009, and 2010). Positive linear trends in yield with increasing rates of N fertilizer (P &lt; .05) were observed in two out of three years. Differences in N removal due to N fertilization were found in all studied years although responses were inconsistent. Nitrogen concentration in harvested biomass increased as N rates and biomass yield increased. Nitrogen use efficiency increased with N rate (P &lt; .05) although many NUE values were negative up to application rate of 100.8 kg N ha−1. Better understanding of nutrient uptake and use efficiency, removal with harvests, and cycling within the plant could provide more refined fertilization practices in switchgrass production.

Growth, nutrition and efficiency in the transport, uptake and use of nutrients in african mahogany

The aim of this work was to study the efficiency of nutrient uptake, accumulation, distribution and use in Khaya ivorensis and Khaya senegalensis , in addition to aspects of growth variables and of dry matter partitioning as a function of mineral fertilisation. The experimental design was a 2 x 2 factorial scheme (with and without the addition of nutrient solution, and two species of African mahogany Khaya ivorensis and Khaya senegalensis ). Morphological, physiological and nutritional parameters were determined in the African mahogany plants 140 days after transplanting (DAT). The greatest zinc (Zn) content was detected in the shoots of both the Khaya ivorensis and Khaya senegalensis plants, accounting for more than 50% of the accumulated total of the plants with added nutrient solution. Maintaining the plants of Khaya senegalensis and Khaya ivorensis with the use of nutrient solution provides the best conditions for nutrient use, and allows plants with excellent morphological and nutritional characteristics to be ready for the field within five months after transplanting in a shaded nursery. The most efficient uptake, transport and use of macro- and micronutrients is found in the species Khaya senegalensis with the addition of nutrient solution.

Interlinkages between human agency, water use efficiency and sustainable food production

Efficient use of water and nutrients in crop production are critical for sustainable water and crop production systems. Understanding the role of humans in ensuring water and nutrient use efficiency is therefore an important ingredient of sustainable development. Crop production functions are often defined either as functions of water and nutrient deficiency or are based on economic production theory that conceptualizes production as a result of economic activities that take in inputs such as water, capital and labor and produce crop biomass as output. This paper fills a gap by consistently treating water and nutrient use and human agency in crop production, thus providing a better understanding of the role humans play in crop production. Uptake of water and nutrients are two dominant biophysical processes of crop growth while human agency, including irrigation machine power, land-preparing machine power and human labor force, determine limits of water and nutrient resources that are accessible to crops. Two crops, i.e., winter wheat and rice, which account for the majority of food crop production are considered in a rapidly developing region of the world, Jiangsu Province, China, that is witnessing the phenomenon of rural to urban migration. Its production is modeled in two steps. First water and nutrient efficiencies, defined as the ratios of observed uptake to quantities applied, are modeled as functions of labor and machine power (representing human agency). In the second step, crop yields are modeled as functions of water and nutrient efficiencies multiplied by amounts of water and fertilizers applied. As a result, crop production is predicted by first simulating water and nutrient uptake efficiencies and then determining yield as a function of water and nutrients that are actually taken up by crops. Results show that modeled relationship between water use efficiency and human agency explains 68% of observed variance for wheat and 49% for rice. The modeled relationship between nutrient use efficiency and human agency explains 49% of the variance for wheat and 56% for rice. The modeled relationships between yields and actual uptakes in the second step explain even higher percentages of observed the variance: 73% for wheat and 84% for rice. Leave-one-out cross validation of yield predictions shows that relative errors are on average within 5% of the observed yields, reinforcing the robustness of the estimated relationship and of conceptualizing crop production as a composite function of bio-physical mechanism and human agency. Interpretations based on the model reveal that after 2005, mechanization gradually led to less labor being used relative to machinery to achieve same levels of water use efficiency. Labor and irrigation equipment, on the other hand, were found to be complimentary inputs to water use efficiency. While the results suggest interventions targeting machinery are most instrumental in increasing wheat productivity, they may exasperate rural – urban migration. Policy strategies for alleviating rural-urban migration while ensuring regional food security can nonetheless be devised where appropriate data are available.

High nutrient uptake efficiency and high water use efficiency facilitate the spread of Stellera chamaejasme L. in degraded grasslands

BackgroundStellera chamaejasme L. is a poisonous plant widely distributes in degraded grasslands in China. The mechanism underlying its spread remains unknown. In some degraded grasslands, S. chamaejasme has gradually replaced previous dominant species, such as Leymus chinensis, Stipa krylovii, Artemisia eriopoda on typical steppes. Apart from its unpalatability by livestock, we hypothesized that the survival strategy (nutrient uptake and water use efficiency) of S. chamaejasme in degraded grasslands could be distinct from other coexisting species in the community. Recently, ecological stoichiometry has been suggested as a new approach for studying the demand for natural resources of plants in a changing world, and the leaf carbon isotopic composition (δ13C leaf) as a rapid and effective high throughput phenotyping method for water use efficiency (WUE), both of which can reveal the survival and adaptive strategies of plants. Therefore, in this study we aimed to fill the knowledge gap concerning ecological stoichiometry in the leaf, stem, and root of S. chamaejasme and its surrounding soil on grasslands with different degrees of degradation, and comparing the leaf nutrient content and δ13C of S. chamaejasme with the coexisting species (L. chinensis, S. krylovii, A. eriopoda) in the communities. Toward this goal, we conducted a field survey in which plants and soils were sampled from four different degraded grasslands on typical steppes in China.ResultsOur results showed that there is no significant difference of carbon content (C%) and nitrogen content (N%) in leaves of S. chamaejasme in different degraded grasslands, and all element contents and element ratios in stems did not differ significantly. Meanwhile, ecological stoichiometry of S. chamaejasme is distinct from the coexisting species, with low C%, high N% and phosphorus content (P%) in the leaf, indicating high nutrient uptake efficiency of S. chamaejasme in nutrient-poor environments like degraded grasslands. Additionally, S. chamaejasme showed significant higher WUE than other species.ConclusionsOur results indicated that high nutrient uptake efficiency and high WUE of S. chamaejasme might together contribute to the spread of S. chamaejasme in degraded grasslands.

Synergistic biorefinery of Scenedesmus obliquus and Ulva lactuca in poultry manure towards sustainable bioproduct generation

Exploiting solar energy for growing algal biomass in waters enriched with farm manures is a holistic method of waste management. The proposed cultivation strategy termed SAR'CENA ('Synergistic Algal Refinery for Circular Economy using Nutrient Analogues), involves integrated cultivation of microalga, Scenedesmus obliquus and marine macroalga, Ulva lactuca in litter to harness biorefinery products. From various litters tested, poultry litter manure (PLM) was most amenable for growth. The microalga yielded 410 ± 6.2 g·DW· m−2· d−1 of biomass with total nitrogen (TN) concentration of 70 mg·L−1 in the media, while the macroalgae yielded 334 ± 9.9 g DW m−2 d−1 of biomass with TN concentration of 17.5 mg·L−1. The nutrient uptake efficiency was observed to be >60% with uncompromised biomass composition. Thus, SAR'CENA is projected as an ideal farming solution incorporating efficient waste management and feedstock generation thereby establishing a circular economy towards clean energy.

Impact of Nitrogen Addition on Physiological, Crop Total Nitrogen, Efficiencies and Agronomic Traits of the Wheat Crop under Rainfed Conditions

Optimizing nitrogen (N) application timings and rate can improve nutrient uptake and nutrient efficiencies in wheat, particularly under rainfed conditions. Climatic stress in the form of high temperature and drought resulted in the decreased crop physiological traits, hastened maturity and, ultimately, caused lower grain yield. The impact of N application rates as full and split dose at three diverse locations of rainfed Pothwar, Pakistan was studied through field experiments for two years (2013–14 and 2014–15). Treatments include T1 = control (no fertilizer applied), full dose of N applied at the time of crop sowing, i.e., T2 = 50 kg N ha−1, T3 = 100 kg N ha−1 and T4 = 150 kg N ha−1, and split application of N at different timings at different stages of the crop, called split application of N, i.e., T5: application of 50 kg N ha−1 (15 kg N ha−1 (sowing, BBCH (Biologische Bundesanstalt Bundessortenamt und Chemische Industrie) 0): 20 kg N ha−1 (tillering, BBCH20): 15 kg N ha−1 (anthesis, BBCH 60), T6: application of 100 kg N ha−1 (30 kg N ha−1 (sowing, BBCH 0): 40 kg N ha−1 (tillering, BBCH 20): 30 kg N ha−1 (anthesis, BBCH 60) and T7: application of 150 kg N ha−1 (45 kg N ha−1 (sowing, BBCH 0): 60 kg N ha−1 (tillering, BBCH 20): 45 kg N ha−1 (anthesis, BBCH 60). The three study sites were Islamabad (high rainfall with optimum temperature), University Research Farm (URF)-Chakwal Road, Koont (medium rainfall with moderate temperature), and Talagang (low rainfall with high temperature). Results revealed that the highest stomatal conductance (0.80 mole H2O m−2 s−1), net photosynthetic rate (20.07 μmole CO2 m−2 s−1), transpiration rate (9.58 mmole H2O m−2 s−1), intercellular CO2 concentration (329.25 μmole CO2 mol−1 air), SPAD values (58.86%) and proline contents (35.42 μg g−1) were obtained from split application of N (T6 = split N100) compared to control and full dose N treatments. Among the sites, these physiological traits remained highest at Islamabad and lowest at Talagang, while between the years, the maximum values of the measured parameters were obtained during 2013–14. A similar trend was observed for crop total N, N efficiencies, and agronomic traits of the crop. The results suggested that the optimum N application rate at appropriate timings can help to harvest the real benefits of N. The split dose resulted in the maximum performance of the crop from the physiological parameters to the agronomic traits of the crop.

A differentiation program induced by bone morphogenetic proteins 4 and 7 in endodermal epithelial cells provides the molecular basis for efficient nutrient transport by the chicken yolk sac.

BackgroundThe mammalian yolk sac provides nutrients for the growing fetus during critical early developmental processes such as neural tube closure, which precedes the functional maturation of the placenta. In contrast, oviparous species such as the chicken rely solely on the yolk sac for transfer of nutrients from the yolk to the developing embryo. However, the molecular mechanisms that provide the yolk sac with nutrient transfer competence remain poorly understood.ResultsWe demonstrate that the chicken endodermal epithelial cells (EEC), which are in close contact with the yolk, gain their nutrient‐transport competence by a paracrine crosstalk with the blood‐vessel forming mesodermal cell layer. Bone morphogenetic proteins (BMP) 4 and 7 produced by ectodermal and mesodermal cell layers likely initiate a differentiation program of EECs during the transition from the area vitellina to the area vasculosa. BMPs, by inducing SMAD signaling, promote the up‐regulation of endocytic receptor expression and thereby provide the EECs with the molecular machinery to produce triglyceride‐rich lipoprotein particles.ConclusionThis paracrine signaling cascade may constitute the basis for the EEC‐mediated mechanism underlying the efficient uptake, degradation, resynthesis, and transfer of yolk‐derived nutrients into the embryonic circulation, which assures proper energy supply and development of the growing fetus.

Screening of microalgae and LED grow light spectra for effective removal of dissolved nutrients from cold-water recirculating aquaculture system (RAS) wastewater

Popularity of recirculating aquaculture systems (RAS) is increasing. Because of the high water recirculation rate, dissolved nutrients originating from fish feed are concentrated enough in RAS wastewater (WW) to enable growth of primary producers, e.g. microalgae. This study evaluated nitrate-nitrogen (NO3-N) and phosphate-phosphorus (PO4-P) removal efficiency of ten temperate zone freshwater microalgae species during their exponential growth phase in unfiltered RAS WW at 17 ± 0.5 °C. Growth and nutrient uptake efficiency of six green and four non-green microalgae strains were compared between WW and reference growth medium in batch monocultures. The effect of three different LED grow light spectra on growth and nutrient uptake efficiency were compared for four green microalgae in WW. The specific growth rate (SGR, 0.5-0.8 d−1) and removal of NO3-N (N%, 57–96%) and PO4-P (P%, 78–94%) of green microalgae in WW in 4 days were comparable to the results obtained in the reference medium (SGR, 0.6-0.9 d−1, N%, 59–99%; P%, 86–99%). In contrast, non-green microalgae had negligible growth (SGR, from -0.1 to 0.2 d−1) and poor nutrient removal (N%, 1–29%; P%, 0–34%) in both growth media after 9 days. The three LED spectra did not differ on their effect on growth and nutrient removal of three green microalgae in WW after 4 days, while the fourth tested species, Haematoccocus pluvialis, had its highest nutrient removal after 8 days under a specific LED spectrum. Current results show that RAS WW supports well green microalgae growth in batch cultures in temperatures common in Nordic RAS and that continuous spectrum LED grow lights can induce high removal of dissolved nutrients. Our findings lend support to the concept of using temperate zone microalgae for nutrient removal and recycling from RAS WW.

Irrigation Salinity Effects on Tifway Bermudagrass Growth and Nitrogen Uptake

ABSTRACTSalinity stress is becoming a more prevalent issue for turf managers due to increased use of recycled water for irrigation. While published data are available on electrical conductivity (EC) thresholds for maintaining adequate turf growth and quality, data are lacking on the relationship between increasing irrigation and/or soil EC and turfgrass nutrient uptake efficiency. The objectives of this greenhouse experiment were to evaluate the effects of five irrigation water sources (reverse osmosis, sodic potable, 2.5 dS m−1 saline [SA], 5 dS m−1 SA, and 10 dS m−1 SA) and two soluble fertilizer N sources (15N‐labeled sources of ammonium sulfate and urea) on Tifway bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] growth responses and N uptake efficiency. Results demonstrated that Tifway bermudagrass was capable of tolerating irrigation EC levels up to 5 dS m−1, which corresponded to final soil EC levels (at 2.5‐cm depth) of ∼2 to 2.6 dS m−1. However, with 10 dS m−1 irrigation (corresponding to soil EC levels of ∼3–5 dS m−1), turf quality declined to unacceptable levels and N uptake noticeably declined. Also, under increasing salinity (salinity levels of 2.5, 5, and 10 dS m−1), urea produced superior turf quality relative to ammonium sulfate. Collectively, the results indicate that for well‐watered, sand‐based Tifway bermudagrass, lower N fertilization rates should be considered once irrigation EC levels exceed 5 dS m−1 or corresponding soil EC levels at the 2.5‐cm depth exceed 2 dS m−1. Although N uptake efficiency of ammonium sulfate was greater than that of urea across all water sources in Year 1, results indicate that urea provided higher turf quality than ammonium sulfate under elevated salinity.

English

A field experiment was conducted to evaluate the effects of different blended fertilizer types (NPSB and NPSBZn) and their rates on fruit yield, nutrient concentration, nutrient uptake and nutrient use efficiency of hot pepper at Assosa, Western Ethiopia. The experiment was set with eight treatments (recommended NP, three different blended rates for each NPSB and NPSBZn and unfertilized plot) laid out in randomized complete block design with three replications using a hot pepper variety Mereko Fana. In the blends since N content was low, supplementary N was applied from Urea to optimize N needs of the crop. The results of the study revealed that the crop phonological parameters (days to flowering and maturity, fruit dry yield and average dry fruit weight) were significantly (p&lt;0.05) affected by blended fertilizer type and rates. The days to flowering and maturity were significantly (p&lt;0.05) improved by application of 100 kg NPSBZn + 29 N kg ha-1. The maximum total dry fruit yields (2.44 t ha-1), the highest fruit uptake of nitrogen (50.1), phosphorus (9.9) and sulfur (4.1 kg ha-1), and the highest apparent nutrient recovery for N (47.91%) were recorded with the application of 150 kg + 44 N kg ha-1 NPSBZn; while higher agronomic efficiency of N (9.59 kg pod kg-1) and P (12.80%) were recorded with the application of 100 kg + 29 N kg ha-1 blended fertilizer rate. In general, the nutrient use efficiency of the blended fertilizers tested was acceptable and high. The uptake of N, P, K and S were significantly and highly correlated (p&lt; 0.01) with total dry fruit yield. Therefore, the study recommends 150 kg NPSBZn + 44 N kg ha-1 blended fertilizer for sustainable hot pepper production in Assosa area of Western Ethiopia. Key words: Blended fertilizer, Mareko Fana, nutrient uptake, fruit yield, nutrient use efficiency. &nbsp;

Effects of vermicompost placement on nutrient use efficiency and yield of tomato (Lycopersicum esculentum)

ABSTRACTThis study investigated different methods of applying vermicompost (VC), with the aims of improving yield in organic tomato production and decrease the amount of fertiliser required. Three methods of placement (application) of the VC were used in the field trial: a) VC placed in a row on the soil surface with incorporation behind the planting lines (R), b) broadcast in the field (B), and c) in the transplant hole under the root plug of the transplant (U). As a second factor, VC was applied at three different rates of application (3, 6 and 9 t ha−1 for R and B, and 2, 4 and 6 t ha−1 for U). In both years, the different rates and placement methods had no significant effect on the fresh yield of tomatoes. However, in 2015, the treatment with the higher rate and the U placement of the VC increased the dry matter (DM) yield of the plants by up to 48% (8.4 t ha−1). Evidently, treatments with the U method had 23 % higher nitrogen (N) uptake (156 kg ha−1) compared with the treatments where VC was broadcast in the field (121 kg ha−1). In 2015, the N use efficiency was significantly higher for the U method (102%) compared with the R and B methods (38 and 34%, respectively) and the phosphorous and potassium use efficiency followed a similar pattern. The study demonstrated that the U placement method for VC increased DM yields, nutrient uptake and nutrient use efficiency in organic tomato production.

Shovelomics root traits assessed on the EURoot maize panel are highly heritable across environments but show low genotype-by-nitrogen interaction

The need for sustainable intensification of agriculture in the coming decades requires a reduction in nitrogen (N) fertilization. One opportunity to reduce N application rates without major losses in yield is breeding for nutrient efficient crops. A key parameter that influences nutrient uptake efficiency is the root system architecture (RSA). To explore the impact of N availability on RSA and to investigate the impact of the growth environment, a diverse set of 36 inbred dent maize lines crossed to the inbred flint line UH007 as a tester was evaluated for N-response over 2 years on three different sites. RSA was investigated by excavating and imaging of the root crowns followed by image analysis with REST software. Despite strong site and year effects, trait heritability was generally high. Root traits showing the greatest heritability (> 0.7) were the width of the root stock, indicative of the horizontal expansion, and the fill factor, a measure of the density of the root system. Heritabilities were in a similar range under high or low N application. Under N deficiency the root stock size decreased, the horizontal expansion decreased and the root stock became less dense. However, there was little differential response of the genotypes to low N availability. Thus, the assessed root traits were more constitutively expressed rather than showing genotype-specific plasticity to low N. In contrast, strong differences were observed for ‘stay green’ and silage yield, indicating that these highly heritable traits are good indicators for responsiveness to low N.

Genetic Screening for Mutants with Altered Seminal Root Numbers in Hexaploid Wheat Using a High-Throughput Root Phenotyping Platform.

Roots are the main channel for water and nutrient uptake in plants. Optimization of root architecture provides a viable strategy to improve nutrient and water uptake efficiency and maintain crop productivity under water-limiting and nutrient-poor conditions. We know little, however, about the genetic control of root development in wheat, a crop supplying 20% of global calorie and protein intake. To improve our understanding of the genetic control of seminal root development in wheat, we conducted a high-throughput screen for variation in seminal root number using an exome-sequenced mutant population derived from the hexaploid wheat cultivar Cadenza. The screen identified seven independent mutants with homozygous and stably altered seminal root number phenotypes. One mutant, Cadenza0900, displays a recessive extra seminal root number phenotype, while six mutants (Cadenza0062, Cadenza0369, Cadenza0393, Cadenza0465, Cadenza0818 and Cadenza1273) show lower seminal root number phenotypes most likely originating from defects in the formation and activation of seminal root primordia. Segregation analysis in F2 populations suggest that the phenotype of Cadenza0900 is controlled by multiple loci whereas the Cadenza0062 phenotype fits a 3:1 mutant:wild-type segregation ratio characteristic of dominant single gene action. This work highlights the potential to use the sequenced wheat mutant population as a forward genetic resource to uncover novel variation in agronomic traits, such as seminal root architecture.

Application of compost in mixed media improved oil palm nursery’s secondary root structure thereby reducing the fertilizer requirement for growth

Although conventional inorganic fertilizers increased plant growth and productivity, their excessive use leads to wastage, run-offs and environmental pollution. In order to promote nutrient recycling and zero emission strategy in the palm oil industry, compost was produced from oil palm empty fruit bunch (EFB) and palm oil mill effluent (POME) anaerobic sludge. The main objective of this study is to determine the effect of compost in the mixed media on the growth and inorganic fertilizer requirement in the oil palm nursery. 100% soil as media with 100% inorganic fertilizer as control was compared with mixed media containing 50% compost in soil with inorganic fertilizer at 25%, 50%, 75% and 100% compositions and tested for plant growth and root structure. The results showed that the treatments with compost addition improved plant growth, compared to the control with 100% inorganic fertilizer which did not contain compost in the mixed medium. The improved plant growth corresponded directly to the enhanced secondary root structure, which probably resulted in more efficient absorption and uptake of nutrients by the plants. Furthermore, the plant growth and the secondary root structure in the mixed media with 50% inorganic fertilizer composition was not significantly different to the media with 75% and 100% inorganic fertilizer. Therefore it is suggested that the application of 50% compost in the mixed media enhanced the secondary root structure, resulting in reduced inorganic fertilizer requirement in the oil palm main nursery, without affecting the plant growth.

Green manures and poultry feather effects on soil characteristics, growth, yield, and mineral contents of tomato

Organic amendments are relatively cheap and available source of organic matter for sustaining both the physical and chemical soil characteristics, and crop yield. Therefore, two field experiments were conducted in 2017 and 2018 to determine the sole and combined effects of Tithonia diversifolia and banana leaves, and poultry feather (PF) on soil characteristics, growth, yield, and mineral contents of tomato (Solanum lycopersicum L.). The treatments were: (i). Tithonia leaves alone applied at 10.0 t ha−1, (ii). Banana leaves alone applied at 10.0 t ha−1, (iii). Crushed PF alone applied at 10.0 t ha−1, (iv). PF at 5.0 t ha−1 + banana leaves at 5.0 t ha−1, (v). PF at 5.0 t ha−1 + Tithonia leaves at 5.0 t ha−1, (vi). Tithonia leaves at 5.0 tha−1 + Banana leaves at 5.0 t ha−1, and (vii). Control – no amendment. The seven treatments were arranged in a randomized complete block design with three replications. Green manures and PF either sole or combined significantly (p < 0.05) reduced soil bulk density and increased porosity, soil organic matter (SOM), nutrient contents, growth, yield, and mineral contents of tomato crop compared with the control. When manures were combined, PF + Tithonia has the highest value of these parameters. PF + Tithonia increased tomato yield by 20.0, 53.0, 77.0 and 132.5%, respectively compared with feather alone, Tithonia alone, banana alone and the control for year 2017, and by 28.3, 59.2, 73.0, and 237.3%, respectively for year 2018. The increased growth, yield, and mineral contents of tomato under PF + Tithonia was due to improved soil physical and chemical properties and also due to the fact that slowly decaying poultry feather may allow retention of released nutrients from rapidly decomposing Tithonia within the rooting zone, thereby fostering greater efficiency of nutrient release and uptake. Therefore, locally sourced organic material can be used in improving soil and crop productivity especially when they are combined.

Silicon attenuates sodium toxicity by improving nutritional efficiency in sorghum and sunflower plants

Salt stress is known to negatively affect the fundamental processes in plants, reducing their growth and yield. The role of Silicon (Si) to protect the sorghum and sunflower plants against salinity stress was assessed. The objective of this study was to evaluate the effects of different forms of Si application on the uptake and use efficiency of macronutrients and micronutrients in sorghum and sunflower plants under salinity stress under greenhouse conditions. Two experiments were conducted using sorghum and sunflower under greenhouse conditions. Four Si levels were applied to plants: no Si application; foliar application of 28.6 mmol.L−1; root application of 2.0 mmol.L−1; and combined Si application with both via nutrient solution and foliar spraying. Each Si treatment was applied in the absence and presence of NaCl (100 mM). Thirty days after treatments, sodium (Na+) and Si accumulation, nutrient uptake and use efficiency, and the roots and total plant dry weight were measured. Salinity stress induced nutritional imbalance and decreased dry weight production in both plant species. Our results showed that Si application alleviated the salinity stress by decreased Na+ uptake and increased nutritional efficiency, thereby favoring the total plant dry weight in sorghum by 27% and sunflower by 41%. This occurred when Si was applied either via root or in combination via root and foliar application, respectively. Collectively, our findings indicate that Si application can attenuate the deleterious effects of salt stress and increase yield in sorghum and sunflower plants in a sustainable manner.