Shoot Yield Research Articles

In vitro clonal micropropagation of selected Malus niedzwetzkyana Dieck forms demonstrating high resilience when introduced into urban environments

Background. Currently, the use of an interdisciplinary approach based on a combination of traditional introduction methods and clonal micropropagation techniques makes it possible to solve one of the key problems of introduction – the establishment of bioresource collections consisting of selected plant accessions with valuable agronomic traits and resistance to unfavorable urban environments. Materials and methods. A plant introduction study resulted in identifying seven specimens of Malus niedzwetzkyana Dieck with resilience to urban environments, high rate of crown development, and longevity. They served as source material for the development of a clonal propagation protocol and in vitro preservation of selected genotypes of this species. Results. It was shown for M. niedzwetzkyana that the most favorable time for taking its plant material for introduction into in vitro culture is the beginning of the active growth of vegetative shoots after flowering. The most optimal sterilization technique for such plant material was a stepwise regime using alcohol, sodium hypochlorite, and silver nitrate: it provided from 50 to 70% of sterile explants and the maximum percentage of meristem proliferation. Combining 0.8 mg/L of benzylaminopurine (BAP) with 0.14 mg/L of indole-3-butyric acid (IBA) at the stage of microclonal propagation ensured a significant increase of the reproduction coefficient (on average up to 5.3 ± 0.7) and an improvement in morphometric parameters of microshoots; the maximum frequency of shoot proliferation was 100%. The yield of shoots adapted to ex vitro conditions was 90%. Conclusion. The developed clonal micropropagation protocol made it possible to introduce selected M. niedzwetzkyana forms into in vitro culture and reproduce them in order to set up a resource base for further fundamental and applied research into the system of the genus Malus Mill.

The Mutual Effects of Pinching and Promalin® on Root Architecture in Two Boxwood Species

Boxwoods are constantly pinched to shape and form hedges, and Promalin® application is used to boost their shoot yield. Having good root development is crucial for the healthy development of plants; however, the effects of such applications on plant root development have generally been ignored in previous studies. Hence, this study evaluated the effects of applications on the root growth of two boxwood species (Buxus sempervirens L. and Buxus balearica Lam.) during the summer dormancy period. Pinching and Promalin® (0, 1 000, 2 000, and 4 000 ppm) were applied to one-year-old seedlings at three different times. Results showed that pinching had a negative effect on root development in both species and both years. Root development was lower in pinched plants than in control plants, which were not pinched. Promalin® at 2 000 ppm was found to be the most effective application on the root parameter. Root development was also higher in the second year than in the first year, depending on temperature, humidity, and the duration of sunshine. It is recommended to apply 2 000 ppm of Promalin® and not prune B. sempervirens. However, if pinching is to be performed, application of Promalin® will be useful to improve root development. For B. balearica, applying pinching and Promalin® together will help increase root development depending on the application time (in periods when the temperature is high).

Foliar spraying KH2PO4 promotes shoot development by inducing stomatal opening and sugar transport in tea leaves

Tea plant is a perennial woody plant that is mostly harvested for its new shoots. Photoassimilates made from mature leaves are the material basis for the formation of yield and quality of new shoots. Potassium dihydrogen phosphate (KH2PO4) as a common foliar fertilizer has been widely used to improve crop yield and quality formation. However, the effect of KH2PO4 on photosynthesis, photoassimilates formation and transportation in tea plants and underlying molecular mechanism remain unclear. Therefore, in the present study, physiological, metabolomics, and transcriptomics analysis between tea plants spraying KH2PO4 and control were performed. The results showed that spraying KH2PO4 could significantly enhance the growth of new shoots. Further, spraying KH2PO4 could effectively increase the proportion of stomatal opening of mature leaves, and significantly increase net photosynthetic rate (Pn), transpiration rate (Tr), and stomatal conductance (Gs). The targeted metabolomics analysis of phloem exudates revealed a significant elevation of sorbitol, arabinitol, d-glucuronic acid, and d-arabinose in mature leaves spraying KH2PO4. Combined with the transcriptome sequencing results, it was found that spraying KH2PO4 significantly induced the up-regulation of genes controlling stomatal opening including HAK17, POT2, ALMT2, ALMT14, PYL4 and PYL2. And the expression levels of photosynthetic antenna proteins such as RA, LHCII type III CAB-13, Lhca3 and LHCI type III LHCA6 were also significantly up-regulated. At last, we found that two polyol transporters, PLT4 and PLT5 were up-regulated. The results revealed the molecular mechanism of KH2PO4 in regulating stomatal opening and the transportation of photoassimilates, laying a theoretical foundation for the application of KH2PO4 in tea plants.

Effect of foliar chelated forms spraying on grape yield and mineral status of shoots

The aim of this study was to evaluate the foliar chelated forms of Mg and Fe, on grape yield and mineral status of the shoots of vine cultivar Cardinal. Field trials were organized using a random block system with three variants, including a control (Variant I), each replicated three times. Foliar fertilizers were applied at a concentration of 0.5% on four occasions throughout the vegetation period: before and after blooming, during buckshot berry stage, and at the verasion stage. Over the ivestigation of three years, the application of foliar Mg and Fe fertilizers significantly influenced grape yield. The variant treated with Fe (VFe) demonstrated a higher average yield of 14.87 t/ha. Furthermore, a noticeable impact of foliar fertilizers on the concentration of analyzed elements in grapevine shoots was observed. Over the three-year period, the average content of macro elements, including nitrogen, phosphorus, calcium, magnesium, and iron, was higher in the treated variants compared to the control. Additionally, results from shoot tissue analysis confirmed the existence of an antagonistic relationship between magnesium and potassium.

Root systems of peanut cultivars respond differently to soil P availability to improve P uptake

AbstractBackgroundPeanut (Arachis hypogaea L.) is regarded as a crop with high nutrient use efficiency, but there may be differences between cultivars. Furthermore, there is little information on the strategy of peanut cultivars to adapt to soil P availability and to what extent they explore non‐labile P pools.AimsOur objective was to evaluate growth, root morphology, enzymatic activity in the rhizosphere, and P uptake of peanut cultivars grown under different soil P status.MethodsThe study was conducted in a greenhouse in 6‐L pots. Soils with low P (without fertilization) and high P content (with fertilization) and seven peanut cultivars of different origins, different maturation groups, and release years were investigated. Peanut shoot yield, phosphorus uptake, root growth, soil P fractions as well as phosphatase activity in the rhizosphere soil were determined.ResultsIn P‐deficient soil, a higher dry matter yield was associated with longer root hairs and root length, which resulted in decreased soil non‐labile P was observed mainly with cultivars developed in Argentina (ARG‐medium‐old and ARG‐medium‐new) and the late maturity Brazilian cultivar (BR I‐late new). These cultivars adapted well to P deficiency and were less dependent on labile P. New Brazilian early and medium maturity cultivars developed less, shorter root hairs, and showed low acid phosphatase activity in the rhizosphere under P deficiency, resulting in lower P uptake and dry matter yield. Under high P availability, new Brazilian cultivars of medium and late maturity showed the highest dry matter yield (9.0 and 9.8 g plant−1, respectively) and longest roots, around 120 m plant−1. High P availability decreased root hairs in all cultivars.ConclusionOverall, the adaptation of peanut cultivars to P‐deficient soils was lower for the new mid‐ and early‐maturing Brazilian cultivars compared with the Argentinian and old or late‐maturing Brazilian cultivars. The main strategies of P‐efficient cultivars under low P availability are to increase root length, root hair length, and root hair density.

Pengaruh Kombinasi BAP (Benzyl Amino Purine) dan Kinetin Terhadap Multiplikasi Tunas Tanaman Tebu (Saccharum officinarum L.) Varietas AAS Agribun

Sugarcane (Saccharum officinarum L.) is a plantation commodity crop and raw material for making sugar. The need for sugar increases every year so it is necessary to provide superior sugarcane seeds in large quantities in a relatively short time. This can be done by propagating using the plant tissue culture method. The research method used was an experimental method using a combined Completely Randomized Design (CRD) with 4 replications and 8 treatments consisting of: Control (P0); 0.5 ppm BAP + 0 ppm kinetin (P1); 1 ppm BAP + 0 ppm kinetin (P2); 2 ppm BAP + 0 ppm kinetin (P3); 0 ppm BAP + 0.1 ppm kinetin (P4); 0.5 ppm BAP + 0.1 ppm kinetin (P5); 1 ppm BAP + 0.1 ppm kinetin (P6); and 2 ppm BAP + 0.1 ppm kinetin (P7). The data then explained the variations and then continued with the DMRT test at the 5% level. The results showed that treatments P3 and P7 showed the best results at the time of shoot emergence. The P3 treatment also showed the best results in the number of shoot (8.25) and number of leaves (16.50). The P7 treatment showed the highest shoot yield (4.58). Keywords: sugarcane, BAP, kinetin, shoot multiplication

Determining the effect of Nitrogen and Sulphur on Growth and Yield of Mustard (Brassica juncea L.)

The experiment was carried out entitled “effect of interaction between nitrogen and sulphur on growth and yield of mustard (Brassica juncea L.)” at the Agronomy Research Farm of Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya (U.P.), India, during Rabi (winter) season of 2021-22. The experiments were conducted in Factorial randomized block design which comprised of 25 treatment combinations in which five levels of Nitrogen (0,40,80,120 and 160 kg N ha-1) and five levels of sulphur (0,25,35,45 and 55 kg S ha-1). The experiments were laid out in the two factors RCBD with three replications, The plant height, number of branches plant-1, dry matter accumulation, seed and stover yield increased with increasing N level of 160 kg N ha-1 which was at par with 120 kg N ha-1 and while significantly superior over rest of the levels of nitrogen. On the other hand, with increasing S levels plant height, increased significantly up to 55 kg S ha-1. However, the number of branches plant-1 and seed yield and shoot yield increased up to the highest dose of S (55 kg S ha-1). Considering the combined effect of N and S, the treatment combination (120 kg n ha-1 and 45 kg S ha-1) produced the maximum seed yield (21.32 q ha-1).

Preferential Phosphorus Placement Improves the Productivity and Competitiveness of Tropical Pasture Legumes

ABSTRACTExtensive grazing systems often receive minimal fertiliser due to the risk associated with using relatively expensive inputs. Nevertheless, nutrient applications are known to improve pasture productivity, and the benefit of applying fertiliser is being more widely accepted. Two tropical pasture mixes (Digit/Desmanthus and Rhodes/Centro) were established in plastic boxes containing phosphorus (P) responsive soil to investigate shoot yield and P fertiliser recovery. The grasses and legumes were planted in separate rows, and three P treatments were applied along with the seed (‘BOTH low‐P’ had 2 kg P ha−1 banded below both components, ‘BOTH high‐P’ had 12 kg P ha−1 banded below both components and ‘LEGUME superhigh‐P’ had 12 kg P ha−1 banded below the legume only). The P applied below the legumes was labelled with 32P‐radioisotope tracer. When P fertiliser was applied below both components, the grasses consistently out‐yielded the legumes (avg. legume content = 29%). Preferential fertiliser application below the legumes increased the average legume content of the two pasture mixes to 66%. Legume tissue P derived from applied P fertiliser increased from 20% to 77% as the P application rate was increased. However, total recovery of applied P by the legumes was relatively low in each of the treatments (≤ 7% of applied P). These collective results demonstrate that a preferential application of P fertiliser can benefit legume productivity, with applied P being a significant proportion of plant tissue P. Although only a small proportion of applied P was recovered within the seven‐week growth period, it is expected that this fertiliser application at planting will remain beneficial for a large proportion of the growing season following pasture establishment.

Phenotypic Variability in Resistance to Anthracnose, White, Brown, and Blight Leaf Spot in Cassava Germplasm.

Despite fungal diseases affecting the aerial parts of cassava (Manihot esculenta Crantz) and causing significant yield losses, there is a lack of comprehensive studies assessing resistance in the species' germplasm. This study aimed to evaluate the phenotypic diversity for resistance to anthracnose disease (CAD), blight leaf spot (BliLS), brown leaf spot (BLS), and white leaf spot (WLS) in cassava germplasm and to identify genotypes suitable for breeding purposes. A total of 837 genotypes were evaluated under field conditions across two production cycles (2021 and 2022). Artificial inoculations were carried out in the field, and data on yield and disease severity were collected using a standardized rating scale. The top 25 cassava genotypes were selected based on a selection index for disease resistance and agronomic traits. High environmental variability resulted in low heritabilities (h2) for CAD, WLS, and BLS (h2 = 0.42, 0.34, 0.29, respectively) and moderate heritability for BliLS (h2 = 0.51). While the range of data for disease resistance was narrow, it was considerably wider for yield traits. Cluster analysis revealed that increased yield traits and disease severity were associated with higher scores of the first and second discriminant functions, respectively. Thus, most clusters comprised genotypes with hybrid characteristics for both traits. Overall, there was a strong correlation among aerial diseases, particularly between BLS and BliLS (r = 0.96), while the correlation between CAD and other diseases ranged from r = 0.53 to 0.58. Yield traits showed no significant correlations with disease resistance. Although the mean selection differential for disease resistance was modest (between -2.31% and -3.61%), selection based on yield traits showed promising results, particularly for fresh root yield (82%), dry root yield (39%), shoot yield (49%), and plant vigor (26%). This study contributes to enhancing genetic gains for resistance to major aerial part diseases and improving yield traits in cassava breeding programs.

Substrates based on carbonized rice husk combined with phosphate fertilization in coriander and mustard seedlings

Combinations of substrates of easy acquisition and nutrients availability favor the production of quality seedlings with lower production cost. Aiming at an alternative for the production of quality seedlings from the insertion of low-cost, sustainable raw material into the commercial substrate, the present work aimed to evaluate the effect of different proportions of the composition of the carbonized rice husk mixture, sand and soil (3:1:3 V:V:V) with commercial substrate (composed of peat fiber and vermiculite), with or without added phosphorus, without development of coriander and mustard seedlings. The experiment was executed in a greenhouse under a randomized block design with six seedlings per plot and seven replications. The treatments were arranged in a 5x2 factorial scheme with 0, 25, 50, 75 and 100 % of the combination added to the commercial substrate with or without addition of triple superphosphate. After 35 days of emergency, plant height, shot dry mass production and roots dry mass production were evaluated. The results showed that there was no effect on the phosphate fertilizer addition to the substrates tested in any evaluated trait, as well as significant interaction between the factors studied in the development of seedlings. The height and dry matter yield of shoots and roots were higher when the combination of carbonized rice husk, sand and soil was added to the commercial substrate in proportions of 50 % and 75 % and 100 % in both vegetables. Carbonized rice husk proved to be an efficient alternative substrate for the production of coriander and mustard seedlings.

Growth, phytochemical concentration, nutrient uptake, and water consumption of butterhead lettuce in response to hydroponic system design and growing season

Two hydroponic system designs (nutrient film technique: NFT, and deep water culture: DWC) were set up in a climate-controlled greenhouse to compare growth, nutrients and water uptake patterns, yield and quality of lettuce (Lactuca sativa cv. Butterhead) during fall (October through November) and summer (July-August) growing conditions. The research was conducted with four system replicates for each hydroponic design and each system contained nine lettuce plants. Plant photosynthetic properties, growth parameters, and irrigation solution nutrient concentrations were measured weekly. At the end of the production cycle, plants were harvested for leaf area, fresh and dry yield of shoots and roots, nutritional and phytochemical concentrations. In the study, DWC system had better water quality properties than NFT including less seasonal water temperature fluctuation, which supported lettuce with better photosynthetic rates, growth rate and fresh yield in fall. Tipburn symptoms were only observed in summer, and NFT grown lettuce had significantly lower shoot calcium and magnesium concentrations than DWC in both fall and summer seasons, which led to more severe tip burn symptom in summer. In addition, better water quality in DWC also benefited lettuce with higher antioxidant concentrations than NFT, which included 9.4 % higher vitamin C in fall, 34.6 % higher total carotenoids in fall, 40.6 % higher non-acidified phenols in fall, as well as 12.9 % higher total chlorophyll in summer. Although there were marginal differences in fresh yield, most types of mineral nutrients and antioxidants between DWC and NFT, DWC performed better than NFT with less tipburn in summer as well as increased yield, total carotenoids, vitamin C and non-acidified phenols in fall.

Assessing the growth dynamics of alfalfa varieties (Medicago sativa cv. Bilensoy 80 and Nimet) response to varied carbon dioxide (CO2) concentrations

Rising atmospheric CO2 levels drive greenhouse effects, elevating temperatures, and diminishing water accessibility in semi-arid regions, affecting agriculture. Alfalfa contributes to climate change mitigation by sequestering carbon, enhancing soil fertility and carbon storage, reducing synthetic nitrogen fertilizer use, preventing soil erosion, supplying high-quality livestock feed, and serving as a bioenergy source. This research examined the effects of elevated CO2 levels in climate change scenarios (600, 800, and 1000 ppm, with control at 400 ppm) on two alfalfa varieties, Medicago sativa cv. Nimet and Bilensoy-80. The experiments were conducted in specialized Climate Change Simulation Greenhouses, allowing control of CO2, water, and temperature variables. Results revealed a positive relationship between higher CO2 concentrations and increased photosynthesis (P ≤ 0.001), promoting the plant growth leaf area (P ≤ 0.001), yields and both leaf (P ≤ 0.05) and stem dry biomass (P ≤ 0.001). At 1000 ppm CO2, a saturation point was reached, halting further photosynthesis. This down-regulation was linked to decreased intercellular CO2 levels, which expedited chlorophyll and breakdown and potentially induced leaf senescence. High CO2 levels led to greater biomass, as anticipated. However, total protein levels, a forage quality indicator, initially decreased with high CO2 concentrations (up to 1000 ppm) due to an inverse relationship with shoot yield. Surprisingly, the 1000 ppm CO2 concentration mitigated this protein reduction in both alfalfa varieties.

Effects of Compound Fertilizer Decrement and Water-Soluble Humic Acid Fertilizer Application on Soil Properties, Bacterial Community Structure, and Shoot Yield in Lei Bamboo (Phyllostachys praecox) Plantations in Subtropical China

Lei bamboo (Phyllostachys praecox) is an economically viable bamboo species with rich nutrition, a good taste, and a high yield. However, heavy fertilization and covering cultivation are used to produce off-season bamboo shoots, resulting in soil degradation and a decline in site productivity. This study investigated how compound fertilizer decrement and water-soluble humic acid fertilizer application affects soil properties and shoot yield in Lei bamboo plantations of subtropical China. The soil nutrients, enzyme activities, and shoot yield were examined, the bacterial community structure was determined using the high-throughput sequencing method, and their relationships were evaluated under different fertilization treatments: single compound fertilizer and compound fertilizer decrement with water-soluble humic acid fertilizer applications. Compared with those after single compound fertilizer treatments (CF1, CF2), water-soluble humic acid fertilizer addition (CF2HA1, CF2HA2) increased soil organic carbon (SOC), available phosphorus (AP), microbial biomass nitrogen (MBN) contents, the ratio of SOC to total nitrogen (C/N), and sucrase and acid phosphatase (Acp) activities, and decreased alkali hydrolyzed nitrogen (AN) and microbial biomass carbon (MBC) contents. The bacterial community phyla comprised 83.62%–86.16% Proteobacteria, Acidobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi. Water-soluble humic acid fertilizer application also significantly increased yields by over 30%. AP and MBN were important drivers affecting soil bacterial communities, whereas SOC, MBN, and Chloroflexi affected Lei bamboo shoots. Overall, compound fertilizer decrement and water-soluble humic acid fertilizer application shifted the available soil nutrients, sucrase and Acp activity, bacterial community diversity, and shoot yield. An improved understanding of humic acid and the application of humic acid water-soluble fertilizer are of great significance for soil improvement, ecological restoration, and the sustainable management of bamboo forests in the future.

Effect of GA3 and Potassium on Growth and Yield in Red Radish (Raphanus sativus L.) under Subtropical Conditions of Jammu

An experiment was carried out at Vegetable Experimental Farm, Division of Vegetable Science, SKUAST Jammu during Rabi season of 2022-2023. The experiment was laid out under factorial RBD design with three replications comprising of sixteen treatments. The treatments consisted of four doses of Potassium i.e., 40, 50, 60 and 70 kg/ha and four concentrations viz. 0,100,200 and 300 ppm of GA3. The growth and yield parameters maximum viz. shoot length (34.15 cm), root length (18.73 cm), number of leaves/root (14.30), root weight (220.49 g), shoot weight (119.47 g), root- shoot ratio (2.04), fresh root shoot yield (112.42 q/ha) were recorded with 200 ppm GA3 application. Similarly, highest shoot length (29.06 cm), root length (17.53 cm), number of leaves/root (11.18), root weight (171.67 g), shoot weight (104.84 g), root-shoot ratio (1.87), fresh root shoot yield (92.31 q/ha), were recorded with 50kg/ha K2O application. However; highest root length (19.20 cm), number of leaves/root (14.87), root weight (226.14 g), shoot weight (123.54 g), root-shoot ratio (2.10), fresh root shoot yield (115.90 q/ha) were recorded with treatment combination G3K2 (200 ppm GA3 + 50 K2O/ha). Based on the investigation, it can be concluded that the application of 200 ppm GA3 at 30 days after sowing with 50 kg potassium/ha resulted in the highest growth parameters and yield.

АКТУАЛЬНОСТЬ ПРОВЕДЕНИЯ МОНИТОРИНГА СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР И ХВОЙНОГО ПОДРОСТА В ВЕГЕТАТИВНЫЙ ПЕРИОД

Modern agriculture faces a number of challenges, including climate change, resource constraints and the need to increase productivity. In this context, the assessment of quantitative parameters of crop growth by technical means during the growing season becomes particularly relevant. The scientific approach to this problem is becoming a key tool for optimizing production and ensuring food security, sustainable development of forest ecosystems. (Research purpose) To substantiate the relevance of monitoring crops and undergrowth during artificial reforestation during the vegetative period. (Materials and methods) Video monitoring of agricultural crops, automated segment recognition, geospatial data, literature review, statistical analysis were used. (Results and discussion) The statistics and problems of existing measures for monitoring coniferous undergrowth after reforestation measures were analyzed. The methods of using video monitoring of agricultural crops, in particular, for analyzing the yield of corn shoots, were considered. The use of a video monitoring system to control the care of coniferous undergrowth in the first five years after reforestation was substantiated. Key limitations and difficulties were cited, including high labor costs, insufficient monitoring, lack of systematic approach, limited human labor and low speed and accuracy of data processing. It has been shown that these factors emphasize the need for innovations in methods of controlling the growth of crops and caring for coniferous young. (Conclusions) It was revealed that the video monitoring system of coniferous undergrowth is one of the solutions to the problems of monitoring the condition of forest areas. It was determined that it allows assessing the quality of planting work, determining the growth and health indicators of seedlings, monitoring the environment by indirect signs and, due to a high level of digitalization and automation, responding quickly to violations. It was stated that the assessment of the parameters of crop growth in real time with the use of technical solutions makes it possible to identify problems such as diseases and parasites at an early stage, which will improve the possibilities for their prevention.

Plant testing with hemp and miscanthus to assess phytomanagement options including biostimulants and mycorrhizae on a metal-contaminated soil to provide biomass for sustainable biofuel production

The need of biofuels from biomass, including sustainable aviation fuel, without using agricultural land dedicated to food crops, is in constant demand. Strategies to intensify biomass production using mycorrhizal fungi, biostimulants and their combinations could be solutions for improving the cultivation of lignocellulosic plants but still lack well-established validation on metal-contaminated soils. This study aimed to assess the yield of Miscanthus x giganteus J.M. Greef & Deuter and Cannabis sativa L. grown on a metal-contaminated agricultural soil (11 mg Cd, 536 mg Pb and 955 mg Zn kg−1) amended with biostimulants and/or arbuscular mycorrhizal fungi, and the shoot Cd, Pb and Zn uptake. A pot trial was carried out with soil collected from a field near a former Pb/Zn smelter in France and six treatments: control (C), protein hydrolysate (a mixture of peptides and amino acids, PH), humic/fulvic acids (HFA), arbuscular mycorrhizae fungi (AMF), PH combined with AMF (PHxAMF), and HFA combined with AMF (HFAxAMF). Metal concentrations in the soil pore water (SPW), pH and electrical conductivity were measured over time. Miscanthus and hemp shoots were harvested on day 90. Both PH and PHxAMF treatments increased SPW Cd, Pb, and Zn concentrations (e.g. by 26, 1.9, and 22.9 times for miscanthus and 9.7, 4.7, and 19.3 times for hemp in the PH and PHxAMF treatments as compared to the control one, respectively). This led to phytotoxicity and reduced shoot yield for miscanthus. Conversely, HFA and HFAxAMF treatments decreased SPW Cd and Zn concentrations, increasing shoot yields for hemp and miscanthus. Shoot Cd, Pb, and Zn uptakes peaked for PH and PHxAMF hemp plants (in μg plant-1, Cd: 310–334, Pb: 34–38, and Zn: 232–309 for PHxAMF and PH, respectively), while lowest values occurred for PH miscanthus plants mainly due to low shoot yield. Overall, this study suggested that humic/fulvic acids can be an effective biostimulant for increasing shoot biomass production in a metal-contaminated soil. These results warrant further investigations of the HFAxAMF in field trials.

Sulfur-improved manganese fertilization for sweet cassava under an overlimed organic management system

The current farm management practices used to cultivate cassava, in a farm from Lago Oeste, Federal District, increased soil pHwater value to 7.11, lowering Mn availability to plants, leading to low root yields. The soils were overfertilized and overlimed. The objective of this work was to evaluate Mn availability for cassava plants, as well as its yield under MnSO4 and elemental sulfur (S0) fertilization, in a high pH soil. An experiment was designed for evaluating MnSO4 (0, 2.5, 5 and 10 kg Mn ha-1) and S0 (0 and 150 kg S0 ha-1) doses on cassava yield. The application of 150 kg S0 ha-1 increased cassava fresh root yield (25.7%), fresh shoot yield (17%), the number of roots (20%) and the starch percentage (7%), and decreased the cooking time (-13%), when compared with treatments without S0. The application of 10 kg Mn ha-1 increased the fresh root yield by 70% as compared to the control treatment. The highest yield was obtained when 10 kg Mn ha-1 and 150 kg S0 ha-1 were applied, rendering 20.16 t fresh roots ha-1, contrasting to the control, which produced 8.83 t ha-1. The applied treatments were essential to increase cassava yield, however, were unable to provide adequate levels of Mn to plants.

The effect of exogenous plant growth regulators on elevated Cd phytoremediation by Solanum nigrum L. in contaminated soil.

Maximizing amendment potential is an emphasis in the HM-contaminated field of phytoremediation by hyperaccumulators due to the low bioavailability of HMs in soils and small biomass yields of plants. This study investigated the influence of different types and concentrations of plant growth regulators on Cd phytoremediation by Solanum nigrum in contaminated soil. Our conclusions showed that the shoot Cd extractions (μg plant-1) and the root and shoot biomasses at all the treatments remarkedly increased compared with that of the CK (p < 0.05), while the Cd concentrations at root and aboveground parts by S. nigrum, the extractable Cd concentrations, and pH value of soils did not change significantly compared with the CK (p < 0.05). Furthermore, correlation analysis showed that the shoot Cd phytoaccumulation and the root and aboveground biomasses of S. nigrum were particularly dependent upon the application of CTK and GA3 concentration gradient (p < 0.05). Moreover, some related physicochemical indexes were determined for supervising the growth conditions of plants, and these results pointed out that after exogenous PGRs treatments, the chlorophyll content and antioxidative enzymes POD and SOD activities in vivo of plants clearly advanced, while the H2O2 and MDA contents and CAT apparently declined. These consequence demonstrated that the exogenous PGR addition prominently reinforced the Cd phytoextraction capacity of S. nigrum in contaminated soil by stimulating plant growth and increasing shoot yields.

Emergence and Early Growth of Four Desmanthus Species in Three Alkaline Clay Soils

Tropical pasture legumes such as Desmanthus are expected to improve pasture productivity in the extensive grazing systems of Northern Australia. However, the soils in these areas are often hostile (e.g., hard-setting and nutrient-deficient), which reduces legume emergence and establishment. Furthermore, these soils are often not ameliorated with amendments such as gypsum or starter fertilisers before planting. A pot trial was conducted to investigate differences in the emergence and early growth of four Desmanthus species. The legumes were grown in three alkaline clay soils that were unamended or amended with either gypsum (1 t CaSO4.2H2O ha−1 equivalent), a starter MAP fertiliser (12 kg P ha−1 equivalent), or both gypsum and the starter fertiliser. Seedling emergence was recorded daily and shoot yield was determined after six weeks’ growth. Final seedling emergence (as a percentage of viable seeds) varied among the Desmanthus species (c.f. D. leptophyllus = 63%, D. pernambucanus = 68%, D. bicornutus = 85%, and D. virgatus = 86%). On average, across the treatments, gypsum increased seedling emergence by 15%, whereas the starter fertiliser had no effect. The shoot yields and shoot phosphorus content of the Desmanthus species generally increased in response to the starter fertiliser. The collective results demonstrated that there were differences in emergence and early growth among the four Desmanthus species, which indicates that Desmanthus cultivar selection may be important in the relatively hostile soils of Northern Australia. Gypsum was an effective amendment for seedling emergence, whereas the starter fertiliser was an effective amendment to increase legume productivity.

Influence of subsoil and soil volume on the accumulation of nickel by Odontarrhena corsica grown on a serpentine soil

Odontarrhena corsica was grown for three months on Chrome loam topsoil and subsoil from near Reisterstown, MD, to examine the effects of varying soil masses (2.8 and 5.6 kg pot−1) and soil layers (topsoil vs. subsoil) on plant growth and Ni accumulation. The subsoil position effect was simulated by placing a pot of topsoil on top of a pot filled with subsoil. Shoot Ni concentrations were similar for all treatments at 7 g Ni kg−1. Shoot yield was significantly higher in the 5.6 kg treatments compared to the 2.8 kg treatments (>18 g pot−1 vs. ∼12 g pot−1) and also greater in the topsoil treatment compared to the subsoil treatment (24.0 g pot−1 vs. 18.6 g pot−1), resulting in significantly higher phytomining. Soil depth had no statistically significant effect on shoot and root yield. Subsoil fertilization increased yield (25.8 g pot−1 vs. 19.7 g pot−1), enough to suggest that further research is warranted to optimize Ni phytomining. This study confirms the importance of soil volume and root access to the subsoil when evaluating the potential for Ni phytomining by Odontarrhena species. The use of small pots may lead to an underestimation of phytomining potential.