Journal of Soil Science and Plant Nutrition最新文献

Arbuscular mycorrhizal fungi (AMF) make associations with the roots of different plant species to improve crop development in a sustainable way. The objective of the present study was to evaluate the effect of different doses of AMF (Rhizophagus intraradices) on the ex vitro development of vanilla (Vanilla planifolia Jacks. ex Andrews) plantlets. Vanilla plantlets were inoculated with different doses: 0, 50, 100, 200, and 300 spores per plantlet (s/p) of R. intraradices during the acclimatization stage. At 120 days of inoculation, the colonization percentage, survival percentage, different growth variables, dry matter, chlorophyll and macro and micronutrient contents of the plantlets were evaluated. An effect of the AMF doses on the evaluated variables was observed. AMF at a dose of 50 s/p showed an efficient symbiotic interaction according to the development variables evaluated. At this dose, with 17% colonization, 96% survival was obtained, while, at doses of 200 and 300 s/p, with 65.3% and 73.3% colonization, the lowest survival percentages were observed, with 63.3% and 53.3%, respectively. In addition, AMF had an effect on the content of the nutrients N, P, Zn, Mn and B, while, for K, Ca, Mg, Fe and Cu, no significant differences were observed. Applying suitable inoculation doses of R. intraradices in vanilla plantlets under greenhouse conditions is an alternative to improve survival and physiological development during acclimatization and allows conditioning prior to transplanting for cultivation.

This study aims to illustrate the temporal and spatial patterns of rhizosphere microecological characteristics of plants highly adapted to heavy metals under different levels of heavy metal stress, to reveal the rhizosphere nutrient cycling and the mechanism of enhanced stress tolerance. The dynamic changes of rhizosphere microecology of Trifolium repens L. (white clover) were studied under different concentrations of Cd treatment. The spatial variation of soil enzyme activities was investigated in situ and microscopically by in situ zymography and the spatial distribution models of enzyme activities were developed. The results showed that the rhizosphere ecosystem remained relatively stable under 40 days of stress, with pH ranging from 7.13 to 7.26 and organic matter contents ranging from 14.83 to 18.09 g kg^− 1. In addition, pH and soil organic matter (SOM) were important ecological factors affecting Cd activation in the rhizosphere. Based on soil zymography analysis, both phosphatase and N-acetyl-glucosaminidase hotspots had root effects, and a maximum hotspot area of 21.51 and 10.19% at 10 mg kg^− 1 Cd treatment, respectively. Besides, the maximum activities of both enzymes were observed at 5 mg kg^− 1 Cd treatment and the rhizosphere extension distance up to 1.82 and 1.59 cm. This study reveals the potential rhizosphere regulatory mechanism of white clover. It was emphasized that the Cd bioavailability was increased in the rhizosphere, the activities of enzymes related to N and P cycling were stimulated under 5–10 mg kg^− 1 Cd stress, and thus soil N loss due to Cd could be compensated in the rhizosphere.

Biochar is considered to have the potential of managing plant diseases by activating plant defense response and influencing the soil-plant-microbe interactions. Therefore, in this study we assessed the soil biochar amendments against bacterial wilt of chilies (Ralstonia solanacearum). Cultivar specific response of chilies to biochar was characterized with reference to physiological and biochemical alterations of the plants. The biochar prepared from leaf waste (LWB) of Syzygium cumini, was applied as a soil amendment at 3 and 6% concentrations along with compost (20%) and the plants were inoculated with or without R. solanacearum. All the cultivars of chilli (Capsicum annumm L.) i.e., F1 Zenia, Desi Chilli and F1 green queen showed a positive impact of biochar amendment on plant growth even under bacterial wilt stress. Although, the reduction in percentage disease index (PDI) and disease incidence (DI) was significant for all cultivars in biochar amended treatments but resistant plant response against wilt was only recorded in cultivar F1 green queen with 6% biochar. The disease response of chili cultivars was not only dependent upon the concentration of biochar in soil but also on the phenolics, catalases and flavonoid contents of the cultivars used. Different chilli cultivars exhibited varied defense response under different biochar concentration. Different chilli cultivars showed variable plant growth in response to the leaf waste biochar amendment. Plant response to disease stress depends not only on the concentration and source of biochar but also on the cultivar. These findings will certainly add to our existing understanding of biochar induced plant resistance as well as cultivar specific chilies defense response against R. solanacearum.

Purpose

Grass pea (Lathyrus sativus L.) has significant nutritional value and broad-spectrum resistance properties. However, the neurotoxin β-N-oxalyl-L-α, β-diaminopropionic acid (β-ODAP) in its seeds increases exponentially during drought stress, and overconsumption can lead to neurogenic hypoparalysis. Superabsorbent polymer (SAP) has the potential to improve soil physicochemical properties and alleviate plant drought stress, but the effects of different SAP concentrations on soil water availability, physiological traits, and β-ODAP content of grass pea under drought conditions are unclear. The objective of this study was to elucidate the impact of SAP on the physiological and biochemical characteristics, as well as the β-ODAP content, of grass pea under drought conditions.

Methods

We conducted potting experiments of natural drought with L. sativus cv. Wugong Yongshou (WGYS), L. sativus cv. Jingbian (JB), L. sativus cv. Aksu (AKS), and cultivated grass pea (ZP) materials with different SAP ratios (0.00%, 0.25%, 0.50%, 0.75%, 1.00%).

Results

The research confirmed that the addition of 0.50% SAP had a positive effect on soil physicochemical properties and growth parameters of grass pea, including plant height, leaf area, leaf water potential, seed yield, and straw yield per plant; Following an eight-day cessation of irrigation, the transpiration rate (E), stomatal conductance (GH₂O), intercellular CO₂ concentration (Ci), and net photosynthetic rate (A) of the four grass pea leaves exhibited a notable optimization in comparison to the control without SAP; The levels of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), malondialdehyde (MDA), and β-ODAP (leaves, seeds, and straw) of four grass pea plants treated with 0.50% SAP were significantly decreased.

Conclusion

SAP can improve soil water-holding capacity, leaf photosynthesis to alleviate oxidative damage caused by drought stress in grass pea, reduce β-ODAP content, and promote low-toxicity and high-yield planting.

Detailed information on the spatial variability of soil aggregate-size fractions (SASF) is crucial for soil erosion modelling and agricultural production. The effects of intrinsic and extrinsic factors on SASF have been widely studied at the grain to small-watershed scales, but rarely studied at the regional scale. This study aimed to investigate the influence of 19 environmental factors on the spatial variability of SASF in southwestern China, where similar tillage practices were used in local tobacco fields. A total of 2238 soil samples were randomly collected from the topsoil (0–20 cm) for analysis. The random forest model was used to identify the relationship between SASF and environmental factors. Random Forest explained 43–54% of SASF variability. Total precipitation during the non-growing period (NGP) was the main factor influencing the variation of SASF, which was 2 to 3 times more important than total precipitation during the growing season (GP) and nitrogen fertilizer application, which ranked second or third, respectively. After NGP exceeded the threshold values, aggregate formation slowed down, while after GP exceeded the threshold values, aggregate fragmentation accelerated. Additionally, excessive nitrogen fertilization not only negatively affected soil aggregate formation, but also weakened the promotional effects of NGP. Overall, our regional-scale study identified the effects of precipitation and nitrogen fertilization on SASF, which might be useful for regional soil erosion modelling and climate-adapted agricultural policies.

Dryland rainfed agriculture needs an appropriate fertilization strategy to achieve sustainable yield with good soil health. This study was aimed at assessing the impact of long-term fertilization on soil available nutrients, its enzymatic activities, and yield and quality of crops. Depth-wise soil samples were collected from a 34-year-old long-term fertilizer experiment (LTFE) with a rainfed rice-lentil cropping system. Treatments used for comparison were: control, 100% NPK (recommended NPK), 50% NPK, 50% FYM (50% of recommended nitrogen from farmyard manure), 100% FYM, and 50% NPK + FYM. Collected samples were analyzed for the physico-chemical and biological properties of soils along with the quality and yield of crops harvested. Among the treatments, 50%NPK + FYM showed the highest activities of dehydrogenase (DHA) (72.7%), alkaline phosphatase (ALKP) (48%), arylsulphatase (ASP) (92.8%) and urease (URE) (112%) compared with the control at the surface layer. It (NPK + FYM) also enhanced soil macro- (available N, P, K and S) and micro-nutrients (available Zn, Cu, Fe, Mn and B). The use of FYM either alone or in combination with inorganic fertilizer, had significant impacts on uptake of macro- and micro-nutrients by grains and straw of rice. Conjoint use of FYM and inorganic fertilizer also improved grain yield of rice (2038 kg ha^-1) and lentil (965 kg ha^-1), values of sustainable yield index (SYI), and quality of rice in terms of enrichment of N, P and K (1.34%, 0.37% and 0.24%) in grains. Results also revealed an improved agronomic efficiency (AE) and apparent recovery efficiency (ARE) of N (38.8%), P (33.7%) and K (91.4%) with FYM. With the exception of control, there was a positive apparent N and P balance shown in all the treatments, whereas negative apparent K balance in all except the FYM-treated plots. Application of NPK with FYM improves soil physico-chemical and biological properties, crop productivity and also its quality. It also ensures a steady supply of N, P and K to crops enhancing their use efficiencies. A balanced and conjoint application of inorganic fertilizer and FYM to rainfed rice-lentil cropping system is recommended for upkeeping soil health, improving crop productivity and its quality under Indo-Gangetic Plains.

Yerba mate (Ilex paraguariensis A.St.-Hil.) can provide many valuable phytochemicals such as methylxanthines, caffeine and theobromine, and caffeoylquinic acids (CQA or CGA– chlorogenic acids). It is necessary to establish cultivation protocols to meet the demand for raw materials with specific phytochemical profiles.

In this study, we analyzed the content and yield of bioactive compounds in leaves of two yerba mate clones submitted to increasing concentrations of nitrogen for two years in a semi-hydroponic cultivation system. The leaves were classified as young or mature and ground after drying in a microwave. The aqueous extracts were analyzed using an Ultra-Fast Liquid Chromatograph (UFLC). The yield was calculated by multiplying compound contents by the leaf dry mass.

Young leaves had higher contents of all compounds than mature leaves. Clone EC40 showed higher contents of caffeine, 4-CQA, and 5-CQA, and this genotype showed a higher yield of all compounds, except for theobromine, when compared to EC22. Increasing nitrogen concentration increased methylxanthines contents; however, the yield of compounds decreased with higher N concentration due to reduced leaf mass production. At the concentration of maximum productivity, 206 mg L^-1 of N, the compound yield reached up to 21 g m^-2 year^-1 of caffeine, and 126 g m^-2 year^-1 of CQAs in clone EC40.

These results demonstrate that the proposed cultivation system is viable, especially with the industrial purpose of extracting yerba mate bioactive compounds. The increase of N in this system does not favor the productivity of bioactive compounds, as it reduces leaf production. The most viable way to suit the desired level of these bioactive compounds in yerba mate leaves seems to be by selecting leaves and clones.

Taurine (TRN) plays a paramount function in protecting against reactive oxygen species (ROS), effectively curbing lipid peroxidation in biological membranes. Additionally, TRN plays a pivotal role in the osmoregulation. Nevertheless, there is a gap in understanding the mechanisms through which TRN brings cellular homeostasis and redox balance, upholds glutathione pool, and curtails copper phytotoxic effects. The current investigation was initiated to assess the impact of TRN seed priming (0.5 and 1 mM) as a mitigative approach to counteract the phytotoxic effects of copper stress (50, 100, and 150 μM) on canola (Brassica napus L.) plants. Copper (Cu) toxicity (50, 100, and 150 μM) notably subsided growth attributes, photosystem efficiency, photosynthetic pigments, leaf relative water content, and acquisition of essential nutrients in plants. Plants encountered increased oxidative injury due to a visible surge in ROS (hydrogen peroxide and superoxide radicals), methylglyoxal, lipoxygenase activity, and lipid peroxidation. A profound increase in the activities of enzymatic antioxidants and levels of non-enzymatic compounds was recorded in plants under Cu stress. Taurine priming significantly diminished oxidative injury by promoting the antioxidant system and visibly abated methylglyoxal levels alongside increasing hydrogen sulphide and nitric oxide content. Plants subjected to TRN-priming exhibited a minimal accumulation of Cu content in aerial parts that could have curbed oxidative stress. The mitigation of oxidative stress notably improves electron transport, photosystem II integrity, and energy dissipation mechanisms. Our study conclusively illustrates that TRN-priming is an efficacious strategy for alleviating the detrimental impacts of Cu toxicity on canola plants. Taurine application reduced oxidative damage and Cu buildup inside plant parts to promote growth, chlorophyll content, ROS metabolism, and methylglyoxal detoxification.

The fertilization with nitrogen plays a crucial role in today’s agriculture characteristic with a high demand for production. The utilization of coated fertilizers represents a possible option to lower the number of applications, lower the dose and limit the risk of environmental losses. The effect of conventional calcium ammonium nitrate (CAN) applied in a single application in blend (1:1 or 1:2) with oil-based polymer coated CAN in thicknesses of 4 (cCAN₄) or 6% (cCAN₆) by weight of the fertilizer on the yield and quality of winter wheat and oilseed rape was evaluate. The average yields of winter wheat were not significantly influenced by the examined fertilization in either the growing season (GS) or the experimental site. On the contrary, the qualitative parameters on average resulted in lower values in comparison with the control (split N fertilization), possibly due to the single application of nitrogen in early spring. The examined treatments significantly influenced the seed yield of oilseed rape in both GS and both experimental sites. On average, the highest yield of seed (2.8 t/ha) was observed on treatment cCAN₄ in a 1:2 ratio. This represents a significant increase by 24.8% compared to the control (2.2 t/ha). Similarly, to winter wheat, the qualitative parameter of oilseed rape (oil content) was lower after the examined blends with coated CAN. The fertilization of oilseed rape with blends of uncoated and coated CAN applied in the single application is a validate alternative to commonly used split nitrogen doses applied repeatedly during vegetation.

Globally, mangrove forests have been impacted by several environmental stressors including overloading with heavy metal pollution. The objective of the current study was to develop a predictive model for estimating heavy metal accumulation at Avicennia marina populations based on sediment characteristics. A transect (170 km) along Saudi Arabia’s southern coast of the Red Sea was selected and three major regions were sampled, and both sediment and plant organs (aerial roots, stems, and leaves) were collected. For both sediment and plant materials, the following metals (mg kg⁻¹) were analyzed: Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, and Zn. Metal Bioaccumulation Factors (BAFs) and Translocation Factors (TFs) were calculated. Moreover, model efficiency (ME) and validation parameters were calculated including coefficient of determination (R²), mean normalized average error (MNAE), and mean normalized bias (MNB). On average, A. marina sediment was moderately to heavily polluted with Pb and Zn (311.2 ± 56.34 and 141.9 ± 19.11 mg kg⁻¹, respectively). Cu, Zn, Mo, Cr, and Pb were translocated from A. marina’s aerial roots to the stems (TF > 1), while Cr, Cu, Zn, Fe, Mo, and Co were translocated from A. marina’s aerial roots to the leaves (TF > 1). The statistical analysis using t-tests showed no significant differences between the observed heavy metal contents and the model-estimated contents within the mangrove's leaves, stems (except for Cd), and aerial roots. Our predictive model to estimate heavy metals in different tissues of A. marina based on sediment characteristics was significantly valid (with exception for stem Cd content). Our results confirm the efficacy of A. marina as a bioindicator of toxic metal for monitoring pollution and application of A. marina as a natural phytoremediation tool.