Soil acidification regulates the mobility of aluminum (Al) and manganese (Mn), thereby affecting legumes growth. Bioenergy by-products (BBP) including biochar, bottom ash and biogas slurry, can mitigate soil metal toxicity in acidic soils; however, the precise impacts of these amendments in soil-plant system remains unknown. Therefore, different treatments of BBP namely Control (T1), Biogas slurry (T2), Bottom ash (T3), Biochar (T4), Biogas slurry with bottom ash (T5), Biogas slurry with biochar (T6), Bottom ash with biochar (T7), and Biochar along with bottom ash and biogas slurry (T8) were used to mitigate the bioavailability and toxicity of Al and Mn. Results revealed that T8 reduced Al and Mn content by 63 % and 78 % in soil and 64 % and 65 % in soybean plants, respectively. Notably, T8 mitigates oxidative damage and improves rubisco activity, photosynthetic efficiency, and antioxidant activities as compared to other treatments. Furthermore, Transmission electron microscopy (TEM) shows that cell structure restoration was obvious under T6 and T8 than that of other treatments. The antioxidant genes (GmSOD, GmCAT1, and GmPOD1) and photosynthesis genes (GmRbcS and GmRCA beta) expressions were upregulated in T7 and T8 than that of other treatments. Our correlations analysis shows that BBP improved soil organic matter and further enhanced the availability of NO3-, P, and K in the soil. Furthermore, increased soil pH by BBP significantly decreased the NH4+ availability in the soil. In conclusion, our study demonstrates that BBP can enhance soybean physiological characteristics by modulating soil pH and improving nutrient availability.

Apolygus lucorum is one of the most important piercing-sucking insect pests of tea plant. In this study, we assessed the impact of intercropping young tea plants with garden pea Pisum sativum on the populations of A. lucorum and natural enemies, tea plant growth and metabolites, and soil nutrient status of tea plantation. Intercropping with flowering P. sativum var. arvense reduced the population density of A. lucorum, particularly between June 1, 2020, and June 15, 2021, with a peak reduction of 90.87%. The percentage of A. lucorum-damaged tea leaves in the tea-pea intercropping was also reduced, with the maximum reduction of 8.96% observed on June 15, 2021, in the intercropping group compared to the control. The tea-P. arvense intercrop had a minor impact on the populations of natural enemies, such as coccinellids, parasitoids, and syrphids in the tea plantations. The tea-pea intercropping increased the contents of soluble sugar, tea polyphenols, caffeine, and anthocyanins, and decreased the contents of free amino acids and catechins of the tea plant leaves, and finally improved the quality of tea. Effective phosphorus and quick acting potassium decreased significantly in the plots intercropped. Our research indicated that tea-pea intercropping has the potential to manipulate the population of A. lucorum and tea leaf damage, and improve tea quality, while also enhancing soil fertility in tea plantations. The findings from this study offer important insights into the use of intercropping as a sustainable agricultural practice.

The production of citrus, a dominant fruit crop globally, is declining due to biotic constraints such as Huanglongbing (HLB) and abiotic stresses such as low or high soil pH. This study aimed to investigate the influence of soil pH on citrus root morphology, nutrient uptake dynamics, and overall root health. Forty 'Valencia' sweet orange [Citrus sinensis (L.) Osbeck] trees grafted on Swingle citrumelo rootstock [C. paradisis x Poncirus trifoliata (L.) Raf] were divided into four groups by pH treatment (n = 10). Trees planted in rhizotron boxes were irrigated three days a week with four different water pH levels: 5.5, 6.5, 7.5, and 8.5. Soil acidity and alkalinity were routinely monitored with pH probes. The concentration of essential macronutrients and micronutrients from the soil, plant tissue, and leachates was also analyzed monthly to evaluate nutrient uptake efficiency. Parameters such as root length, root surface area, and root diameter were measured to assess the morphological changes in citrus tree roots under different pH treatments. After irrigation, soil pH on treatment with pH = 5.5 decreased drastically since sandy soils acidify more quickly. Soil pH levels for treatments irrigated with solutions at pH 6.5 and 7.5 consistently maintained near-neutral levels, with the former gradually decreasing soil pH over time and then later increasing the soil pH to alkaline levels. The soil P and S concentrations were high at pH = 5.5, contrary to the Mg and Ca concentrations, which were low at the same pH level. Soil pH showed a significant and negative correlation with S, P, and Fe, indicating a decrease in these soil nutrients as soil pH decreased and a nonsignificant positive correlation with Cu. At pH = 5.5, there was significantly higher root growth, which indicates that acidic soils (similar to pH = 5.5) can enhance root growth in citrus trees. Acidic soils stimulate root growth, particularly around a pH of 5.5; citrus roots exhibit remarkable resilience and internal compensation mechanisms in response to pH changes. Optimizing soil pH and nutrient management can mitigate the impacts of HLB and promote the resilience of citrus trees. Trees irrigated at pH of 8.5 showed a trend of fewer living roots and lower cumulative root growth, emphasizing the possibility of root damage due to high soil pH.

Polymer-coated controlled-release fertilizers (PC-CRFs) are valued for nutrient efficiency, but concerns remain about the long-term impacts of their plastic coatings on soil health. This study investigates the physicochemical characteristics of two commercially available PC-CRFs, type A and B, and their changes during nutrient release. Accelerated nutrient release experiments were conducted for 25 d in ultrapure water (free water) and saturated soil with five wet-dry cycles. Total phosphorus and total nitrogen release were measured, with lower concentrations found in soil column effluent compared to water. Additionally, studying microplastic (MP) release from type A PC-CRFs during nutrient release showed that a significantly greater number of MPs were released in the soil column than in water. The results also indicated a preferential migration of smaller MPs to the deeper layers of the soil column. Microscopic pores and cracks were observed through surface morphology analysis, likely caused by osmotic pressure during nutrient release, potentially contributing to MP generation. Mechanical degradation of the type A PC-CRF microcapsules was assessed through surface wear and shear tests to simulate the forces exerted by soil particles and agricultural machinery. Our results showed that longer surface wear duration increased the number of generated MPs, while higher loading in surface wear experiments resulted in a larger median diameter of the MPs.

Cadmium (Cd) contamination in agricultural soil and accumulation in rice poses serious threat to human health. It is reported that Selenium (Se) can mitigate the toxic effect of Cd in rice. But the underlying mechanism of Se preventing the Cd accumulation and restoring the micronutrient content in rice grains have not been studied before. Therefore, our main aim is to reduce Cd content and restore micronutrient content in rice grain and study the mechanism. Two indigenous rice genotypes (Maharaj and Jamini) were exposed to 10 and 50 mu M Cd in presence and absence of Se (5 mu M) with a control set and assessed for plant growth, biomass, Cd content, ROS and antioxidants for Cd induced toxicity and amelioration. Genes for micronutrient transporters were studied by RT-PCR. Grain Cd and micronutrient content and agronomic parameters were also studied. Se supplementation increased plant growth, biomass, and yield under Cd stress. SEM and EDX analysis revealed that Se-Cd complex formed on root surfaces restricted Cd uptake by the roots preventing root damage. Soil analysis confirmed that Se decreased Cd bioavailability, restricted root to shoot Cd translocation, ultimately reducing Cd accumulation and restoring micronutrients in grain. This was further validated by fluorescent Leadmium dye staining. In (Se + Cd) treated seedlings, up-regulation of S metabolism and nutrient transporter genes also contributed to the mitigation of Cd stress. The Se supplementation can be considered as a cost-effective, ecofriendly and sustainable approach to produce Cd free rice cultivation in Cd polluted soil.

Purslane (Portulaca oleracea L.) is an herbaceous species that is traditionally consumed across the world due to its nutraceutical quality, boasting anticancer, anti-inflammatory and antidiabetic properties. These traits render purslane an attractive wild edible species for research and commercial exploitation. The current study examined the effect of different nitrogen (N) concentrations (100-200 mg L-1; as N100, N200) in combination with different levels (decreased 0.66-fold: dec, recommended 1-fold: rec, or increased 1.5-fold: inc) of phosphorus (P; 47-70-105 mg L-1) and potassium (K; 250-350-525 mg L-1) in the nutrient solution (NS) used in hydroponic nutrient film technique (NFT) cultivation. The N200_PKinc NS resulted in improved crop growth compared to N200_PKrec NS, suggesting a positive correlation between optimal N levels (i.e., 200 mg L-1) and increased P and K levels (105 and 525 mg L-1, respectively). Plants grown in N200_PKinc revealed decreased antioxidant activity (e.g., DPPH, FRAP, and ABTS), phenols and flavonoids, while simultaneously increased total soluble solids levels. The recommended levels of P and K mirrored low levels in lipid peroxidation, mainly due to the increase in catalase enzymatic activity. Higher nutrient use efficiency was observed when both N100_PKinc and N200_PKinc were applied, resulting in higher yield and enhanced plant growth, while N100_PKinc produced plants with increased antioxidant activity. These findings suggest that both (N200_PKinc and N100_PKinc) NS have potential benefits for the hydroponic cultivation of purslane, with the latter NS offering additional advantages in terms of higher produce quality.

D ROUGHT is a highly damaging abiotic stress that affects crops' development, functioning, productivity, and quality. In contemporary farming, nanoparticles are advantageous because of their extensive surface area and enhanced ability to penetrate plant leaves when applied as a spray. Lately, nano-fertilizers have been employed in agriculture to help reduce the negative impacts of drought stress. This study aims to investigate the effects of different forms (nano and chelated) of iron (Fe), zinc (Zn), and manganese (Mn) foliar application, as well as their combinations, on the growth, yield, and water productivity of faba bean plants under different soil moisture levels (100, 80, and 60% of field capacity, FC). The results indicated the best readings of traits studied in the faba bean plant were observed under soil moisture at 100% of FC (control) compared to 60% of FC. On the other hand, results showed that the combined foliar application (FA) of FeZnMn-nanofertilizers (FeZnMn-NFs) to faba bean plants yielded the most favorable growth characteristics and chlorophyll content compared to the untreated plants (control). Also, the FA of FeZnMn-NFs treatment resulted in the highest seed yield and macronutrient (NPK) content in both straw and seed. The seed yield under FeZnMn-NFs treatment (21.24 g pot-1) was significantly more significant than the control (15.47 g pot-1). Regarding water use efficiency (WUE), the FeZnMn-NFs treatment achieved the highest WUE for the faba bean (2.44 kg m-3) compared to the control (1.60 kg m-3). Conversely, the amount of irrigation water applied (IWA) was lowest with the FeZnMn-NFs treatment (8.72 L pot-1) compared to the control (9.64 L pot-1). Concerning the interaction between irrigation levels and foliar spray treatments of faba bean plants, there were no significant differences in seed yield between the 100% irrigation level and the 80% level when foliar application of FeZnMn-NFs. Additionally, nano-fertilizers (NFs) demonstrate greater effectiveness than chelated fertilizers (EDTA), significantly enhancing yield and macronutrient content. Thus, the results highlight the crucial role of NFs in mitigating damage from drought stress, improving growth characteristics, and saving 20% of the amount of IWA for faba bean plants, allowing it to be used elsewhere in agriculture. Consequently, these findings suggest that using NFs of Fe, Zn, and Mn as foliar applications (FA) could be a promising approach to boost the growth parameters, seed yield, and WUE of faba bean plants in arid and semi-arid regions.

A major global concern for food security and human health is the indiscriminate discharge and consequent accumulation of heavy metals from various anthropogenic sources into the environment. Chromium (Cr) is one of the most common toxic effluents that pollute agricultural soil. Chromium intake affects plant metabolism, photosynthetic activity, growth, and productivity. In the present study, triacontanol (TRI) was exogenously supplied via seed priming and foliar spraying (10 ppm and 20 ppm) to alleviate Cr (60 mg/kg) stress in Raphanus sativus L. (radish). Chromium reduced shoot length by 65.21%, roots length by 66.28%, gas exchange attributes by 36.23%, mineral content by 52.55%, and phenol content by 11.11%, but the ascorbic acid content increased by 43.23%. Moreover, 2,2-diphenyl-1-picrylhydrazyl (DPPH) activity increased by 26.34%, which reduced the degree of oxidative damage caused by Cr. Additionally, elevated nutritional contents (Zn+2, Mg+2, K+, and Na+), total photosynthetic pigments (34.42%) and proline contents were correlated with relatively higher levels of ascorbic acid. Interestingly, exogenous TRI administration reduced the oxidative damage caused by Cr. In general, our findings demonstrated that seed priming and foliar supplementation with TRI improved R. sativus plant's tolerance to Cr by reducing its accumulation and restoring oxidative equilibrium.

Generally, with increasing elevation, there is a corresponding decrease in annual mean air and soil temperatures, resulting in an overall decrease in ecosystem carbon dioxide (CO2) exchange. However, there is a lack of knowledge on the variations in CO2 exchange along elevation gradients in tundra ecosystems. Aiming to quantify CO2 exchange along elevation gradients in tundra ecosystems, we measured ecosystem CO2 exchange in the peak growing season along an elevation gradient (9-387 m above sea level, m.a.s.l) in an arctic heath tundra, West Greenland. We also performed an ex-situ incubation experiment based on soil samples collected along the elevation gradient, to assess the sensitivity of soil respiration to changes in temperature and soil moisture. There was no apparent temperature gradient along the elevation gradient, with the lowest air and soil temperatures at the second lowest elevation site (83 m). The lowest elevation site exhibited the highest net ecosystem exchange (NEE), ecosystem respiration (ER) and gross ecosystem production (GEP) rates, while the other three sites generally showed intercomparable CO2 exchange rates. Topography aspect-induced soil microclimate differences rather than the elevation were the primary drivers for the soil nutrient status and ecosystem CO2 exchange. The temperature sensitivity of soil respiration above 0 degrees C increased with elevation, while elevation did not regulate the temperature sensitivity below 0 degrees C or the moisture sensitivity. Soil total nitrogen, carbon, and ammonium contents were the controls of temperature sensitivity below 0 degrees C. Overall, our results emphasize the significance of considering elevation and microclimate when predicting the response of CO2 balance to climate change or upscaling to regional scales, particularly during the growing season. However, outside the growing season, other factors such as soil nutrient dynamics, play a more influential role in driving ecosystem CO2 fluxes. To accurately upscale or predict annual CO2 fluxes in arctic tundra regions, it is crucial to incorporate elevation-specific microclimate conditions into ecosystem models.

Fibrous plants with higher biomass, particularly industrial hemp, have ability to withstand and accumulate significant quantities of heavy metals from contaminated environments. The present study aimed to evaluate the dynamics of different levels (ratios) of macronutrients nitrogen, phosphorus and potassium (NPK) viz., NPK1--NPK (1:1:1); NPK2--NPK (2:1:1); NPK3--NPK (3:1:2); NPK4--NPK (4:1:2) on hemp growth and Cu contents under various levels of Cu stress (100, 400 and 800 mg kg- 1 on dry soil basis using CuSO4 & sdot;5H2O). Results revealed that by increasing the Cu stress, growth and biomass decreased linearly and lipid per oxidation and enzymatic antioxidants increased. Balanced application of NPK improved the biomass and decreased the membrane damage by the modulation of malonaldehyde contents. Maximum concentration of Cu in roots (377.47 +/- 4.90 mg kg-1), shoots (137.45 +/- 5.60 mg kg-1) and (150.07 +/- 3.57 mg kg-1) was recorded at Cu3NPK2 treatment as compared to control. Maximum translocation factor (TF) and bioaccumulation coefficients (BAC) in the shoots and leaves of hemp plant were noticed where Cu stress was applied at the rate of 100 mg kg- 1. However, BAC and TF were below 1. The NPK2 treatment enhanced biomass and increase Cu content both in leaves and stems, rather than the roots. Our study suggests that balanced application of NPK is a practicable approach to alleviate Cu stress and improve biomass production of industrial hemp plant. These findings indicate that optimum nutrient supply, under Cu stress, can maximize the growth potential and overall health of industrial hemp, making it a viable option for phytoremediation and sustainable agriculture on contaminated soils.