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The chestnut tree (Castanea sativa Mill.) is gaining importance in the mountainous regions of southern Europe due to the high value of its fruits. It is essential to establish effective cultivation protocols, considering that this species is still relatively understudied. In this study, we present the outcomes of the initial establishment of a chestnut orchard conducted through a nutrient omission trial for four years. The treatments included a fertilization plan with nitrogen, phosphorus, potassium, and boron (NPKB), the control, and four other treatments corresponding to the omission of each nutrient (-NPKB, N-PKB, NP-KB, NPK-B). The -NPKB and NP-KB treatments showed significantly lower trunk circumferences and canopy volumes compared to the other treatments. The NPK-B treatment resulted in the lowest fruit production, with a total accumulated yield (2020–2022) of 0.56 kg tree–1, a value significantly lower than that of NPKB (1.12 kg tree–1) and N-PKB (1.19 kg tree–1). The assessment of nutrient concentrations in the leaves revealed plants with deficient levels of B and K in treatments that did not receive these nutrients. Conversely, N levels in the leaves in the -NPKB treatment fell within the sufficiency range (20 to 28 g kg–1). This suggests that the sufficiency range should be adjusted to higher values, given the treatment's effect on tree growth. It was also observed that the -NPKB treatment led to lower soil organic matter compared to the other treatments, likely due to reduced herbaceous vegetation development under the canopy, leading to decreased organic substrate deposition in the soil. The main findings of this study are that N and K were crucial elements for the optimal growth of chestnut trees, while B played a significant role in fruit production. [ABSTRACT FROM AUTHOR]

Seed inoculation with symbiotic bacteria is a commonly employed practice in soybean cultivation. As a result, nodulation proceeds properly and plants self-supply atmospheric nitrogen, requiring either minimal or no additional nitrogen fertilization. The aim of the study was to investigate the response of soybeans to the application of the recommended or double dose of commercial inoculants (HiStick® Soy or TURBOSOY®) and/or mineral nitrogen fertilization compared to the untreated control. It was demonstrated that a double dose of the tested preparations had the most favorable effect on nodulation. However, the impact of weather conditions modified their effectiveness during the study years, which was especially visible in 2022. Sowing seeds without inoculation (control) resulted in the formation of sparse root nodules and consequently the lowest leaf area index (LAI) and soil plant analysis development (SPAD) measurements. In addition, the values of SPAD and LAI indices varied across the years of the study, indicating that weather conditions modified nitrogen uptake by plants. Overall, seed inoculation and/or nitrogen fertilization positively influenced the chemical composition of seeds compared to the control. The only decrease observed was in the oil content, while the double dose of HiStick® Soy preparation reduced the polyphenol content. The double dose of the tested inoculants had the most favorable impact on yield components and seed yield. However, applying inoculation at the recommended dose or in combination with nitrogen fertilization yielded similar or slightly worse results, depending on the year. Therefore, soybean seed inoculation should be recommended, although the effectiveness of the procedure will depend on various factors, including the type of inoculant, dosage, nitrogen fertilization, and weather conditions. [ABSTRACT FROM AUTHOR]

Both southern and northern regions of Italy are experiencing reduced precipitation and increased heat waves due to climate change, negatively affecting agricultural sector. Urban wastewater could be a solution to this problem, providing a constant source for irrigation and reducing synthetic fertilizer use. This research presents a two-year field study on using tertiary treated wastewater for processing tomato crop irrigation through an innovative smart fertigation system, designed to supply the exact doses of NPK nutrients considering those already delivered to the plants via the irrigation water. With the aim of studying the effects of irrigation with treated wastewater, three water sources were compared: fresh water added with chemical fertilizer, tertiary treated wastewater added with chemical fertilizer and tertiary treated wastewater without addition of fertilizer. The proposed system was efficient and consistent with the design, it saved considerable amounts of fertilizers, handling nutrient fluctuations in wastewater. Of the three irrigation water types that have been tested, only the one that used tertiary treated wastewater alone without additional fertilizers was not capable of meeting tomato nutritional needs, despite the fact that significant macronutrient savings were achieved. No negative effects on soil or plant physiological performances were observed. Plants irrigated with wastewater showed similar growth and productivity to those irrigated with fresh water and no significant differences in fruit quality were found, highlighting the benefits of wastewater reuse for crop irrigation.

Context. Root symbionts affect forage production by influencing host plant growth, but their specific effects on canopy intercepted photosynthetically active radiation (IPAR) and its conversion to plant biomass have not been investigated. Aims. We evaluated the extent to which changes in plant biomass resulting from arbuscular mycorrhizal fungi (AMF) and rhizobia can be explained by alterations in IPAR and aboveground and total radiation-use efficiency (RUE: the ratio between shoot or total biomass and IPAR). Methods. Under controlled greenhouse conditions, we evaluated single and dual inoculation effects of AMF and rhizobia on the forage legume white clover (Trifolium repens L.). Experimental units comprised canopies created in trays (50 cm by 34 cm by 13 cm deep). Key results. On average, AMF inoculation increased IPAR by 43%, owing to greater leaf area and density, and decreased total RUE by 30%. Aboveground RUE was lower in AMF-inoculated plants without rhizobial inoculation, despite their higher leaf phosphorus status and greenness during the vegetative and reproductive stages, respectively. Rhizobial inoculation reduced the negative effect of AMF inoculation on aboveground RUE. Conclusions. Both AMF and rhizobia alter white clover structure and function at canopy level. These variations may not be detected if the analysis considers only the impact of root symbionts on plant biomass. Implications. These findings offer valuable insights into the intricate interactions between root symbionts and canopy-level processes, providing a basis for further research at agricultural scale. [ABSTRACT FROM AUTHOR]

Seed inoculation with symbiotic bacteria is a commonly employed practice in soybean cultivation. As a result, nodulation proceeds properly and plants self-supply atmospheric nitrogen, requiring either minimal or no additional nitrogen fertilization. The aim of the study was to investigate the response of soybeans to the application of the recommended or double dose of commercial inoculants (HiStick® Soy or TURBOSOY®) and/or mineral nitrogen fertilization compared to the untreated control. It was demonstrated that a double dose of the tested preparations had the most favorable effect on nodulation. However, the impact of weather conditions modified their effectiveness during the study years, which was especially visible in 2022. Sowing seeds without inoculation (control) resulted in the formation of sparse root nodules and consequently the lowest leaf area index (LAI) and soil plant analysis development (SPAD) measurements. In addition, the values of SPAD and LAI indices varied across the years of the study, indicating that weather conditions modified nitrogen uptake by plants. Overall, seed inoculation and/or nitrogen fertilization positively influenced the chemical composition of seeds compared to the control. The only decrease observed was in the oil content, while the double dose of HiStick® Soy preparation reduced the polyphenol content. The double dose of the tested inoculants had the most favorable impact on yield components and seed yield. However, applying inoculation at the recommended dose or in combination with nitrogen fertilization yielded similar or slightly worse results, depending on the year. Therefore, soybean seed inoculation should be recommended, although the effectiveness of the procedure will depend on various factors, including the type of inoculant, dosage, nitrogen fertilization, and weather conditions.

Due to the high value of the fruit, the European chestnut (Castanea sativa Mill.), usually grown in agroforestry systems, has been planted as a single species in orchards managed with increasingly intensive cropping practices, such as the regular use of fertilisers. This justifies research into establishing fertilisation programmes oriented towards ecological intensification. In this study, the results of fruit production, plant nutritional status and soil properties are reported from a field trial in which three NPK fertilisers (20:7:10, 13:11:21 and 7:14:14) and a control treatment were used. Chestnut yields did not vary significantly between treatments, although the mean values of the control showed a clear downward trend. N supplied by the fertilisers seems to have been the most important factor in the difference between the fertilised and control treatments, since leaf N concentrations were lower in the control and often below the lower limit of the sufficiency range. Soil inorganic N levels in the autumn, and tissue N concentrations of the herbaceous vegetation developing beneath the trees, indicated risks of N loss to the environment and highlighted the importance of this vegetation remaining during the winter. The chestnuts' poor response to fertiliser applications was attributed to the buffering effect of the large perennial structure of the trees on the distribution of nutrients to the growing plant parts. In large trees, it seems appropriate to base the annual fertilisation plan on leaf nutrient concentration. Thus, farmers probably should avoid spending money on fertilizer applications as long as leaf nutrient concentrations do not approach the lower limits of sufficiency ranges. [ABSTRACT FROM AUTHOR]

Municipal solid waste compost (MSWC) is a source of organic C and other nutrients, which, when free from potential contaminants, can be used as a soil amendment. This study was carried out over three years in a vineyard with soil pH close to neutral under an experimental design consisting of two treatments (with and without MSWC). Application of MSWC is currently authorized under national legislation to be used in vineyards, orchards and forests at a maximum rate of 10 t ha−1 year−1. In this study, for experimental purposes, a double rate (20 t ha−1 year−1) was used. The accumulated grape yield increased in the amended plot by 28% and the dry biomass of weeds between rows by 119%. The MSWC significantly increased some relevant soil properties such as organic C, pH, cation exchange capacity (CEC) and extractable P, K and B. The concentration of K increased significantly in several tissues, and the concentration of P decreased. However, the concentration of K, P and other essential nutrients in the leaves remained within their sufficiency ranges. Tissue levels of heavy metals (Cr, Cd, Pb and Ni) did not increase with the MSWC application, and the values in the pulp remained below the limits established for foodstuffs. The results from this study indicate that the continuous application of the MSWC does not seem to be sustainable, because of the risk of causing nutritional disorders. Products with similar composition should therefore be used only on more acidic soils and should never exceed the legally established rates. [ABSTRACT FROM AUTHOR]

Farmers are increasing the use of fertilizers in chestnut, the only cash crop produced in the mountainous areas of northeastern Portugal. This calls for more studies to guide them towards a more ecological intensification. The effects of three controlled-release fertilizers, two that release nutrients over three months (BoskGrow 20:05:20_3m, Exactyon 18:05:13_3m) and one over six months (Exactyon 18:05:12_6m), and an organic amendment authorized for organic farming (Humix 12:03:05) were compared with an untreated control during a three-year field trial (2019–2021). BoskGrow 20:05:20_3m, Exactyon 18:05:13_3m and Humix 12:03:05 gave significantly higher nut yields (90.6 to 97.0 kg tree−1, average 2019 + 2021) than Exactyon 18:05:12_6m (66.3 kg tree−1) and the control (69.5 kg tree−1). Leaf concentrations of nitrogen and potassium tended to be higher in the BoskGrow 20:05:20_3m and Exactyon 18:05:13_3m treatments, and they were stated as the most important causes in the establishment of the two productive groups. Humix 12:03:05, although less concentrated in nutrients, led to a chestnut yield at the level of the most productive treatments, possibly due to the multiple positive effects of organic matter on soil and plants. Under the conditions of this experiment, where rainfall is low in the summer, fertilizers whose nutrient release takes a long time, such as Exactyon 18:05:12_6m, seem not to be a good fertilization option due to reduced nutrient uptake and increased levels of soil inorganic nitrogen at the end of the growing season. Humix 12:03:05 emerged as a possible solution for organic producers.

ABSTRACT The use of saline water in agriculture has increased in the Brazilian semiarid due to low availability of good quality water for irrigated agriculture, being the selection of salt tolerant hybrids an alternative to reduce the effect of salinity on nutritional status of plants. So, the objective of this work was to evaluate the effect of salinity of irrigation water in the accumulation and partition of nutrients in the vegetable tissue of watermelon cultivars, in the region of Mossoro in the State of Rio Grande do Norte, Brazil. The treatments studied consisted of applying irrigation water with five electrical conductivities (EC1 = 0.57, EC2 = 1.36, EC3 = 2.77, EC4 = 3.86 and EC5 = 4.91 dS m-1), two watermelon cultivars and four samplings times (15; 29; 43 and 60 days after transplanting), arranged in a scheme of split plot(5x2x4) and outlined in complete blocksrandomized with four replications. The accumulated nutrients in plants were influenced by ECw, occurring a loss in comparison with the higher ECw of 24.1 and 36.4% in the accumulationof N and P in the vegetative part of plant and 37.8 and 30.1 % in the accumulation of P and K in the aerial part. The accumulation of N, P and K in the watermelon was influenced by plant age, with reduction at the end of the cycle.

Abstract Extrafloral nectaries (EFNs) are nectar secretory structures involved in the indirect defense of plants. In the sponge gourd (Luffa cylindrica), EFNs commonly occur on the lower surface of leaf blades and stipules and remain functional until leaf senescence. To test the hypothesis that the development of EFNs is influenced by herbivore damage and resource availability, we grew Luffa cylindrica under different concentrations of Hoagland's nutrient solution (nutrient-poor conditions: 10%, 50%; and control condition: 100%) and two herbivory treatments (damaged and undamaged leaves). We collected ten leaves from treated plants to quantify leaf area and EFN density. Overall, leaf area increased and EFN decreased in damaged plants, but this significantly depended on nutritional status. In undamaged plants, EFN density tended to remain constant, whereas foliar area increased with nutrient input. Under herbivory, foliar area increased at 10% but decreased at 50 and 100% of nutrients in relation to undamaged plants, whereas EFN density tended to increase with nutrient availability to exceed undamaged plants under control concentrations. Plants under nutrient-poor conditions subjected to herbivory exhibited an increased foliar area, characterizing a compensatory mechanism. Our results suggest that herbivore-induced indirect defense is a damage- and resource-dependent response in Luffa cylindrica. These findings contribute to understanding the factors that modulate indirect defenses and plant-herbivore-environment interactions. Highlights • Luffa cylindrica produces numerous herbivore-induced extrafloral nectaries (EFNs). • This species shows an herbivore- and resource-induced indirect defense response. • In experimentally-damaged plants, leaf area increased and EFN density decreased. • The effect of herbivory on foliar area and EFN density depends on nutritional status. • Nutrient-poor plants subjected to herbivory exhibited a compensatory mechanism. [ABSTRACT FROM AUTHOR]

This study was conducted to compare the yield, yield parameters and nutrient contents of leaves and pseudostems of leeks grown organically with those of leeks grown conventionally and control (received no treatments). In the study, three different plant activators (Crop-Set, Soil-Set and Manda 31) were used to perform organic production. At the end of the study conducted for two years, it was determined that the yield, plant weight, plant length, pseudostem length, and pseudostem diameter varied among treatments between 4.6-8.4 tons/da, 136.47-252.44 g, 107.3-123.6 cm, 38.2-42.7 cm and 15.93-21.57 mm respectively. Moreover, while the amounts of nitrogen, phosphorus and potassium in the leaves varied between 2.32-3.42%, 0.61-0.71% and 3.82- 4.50% respectively, their amounts in the pseudostems showed changes between 1.53-2.98%, 0.36-0.44% and 2.68-3.42% respectively. [ABSTRACT FROM AUTHOR]

Nowadays, treated municipal wastewater is considered as an alternative water source for irrigation, crucial mainly under dry environments; however, if not well managed, it could negatively affect crops and environment. Four irrigation water sources were tested in order to evaluate their impact in a nectarine orchard: three unconventional wastewaters – including a secondary-treated municipal wastewater (SW), a wastewater made by a simplified lagoon treatment pilot plant (LW), and a tertiary-treated wastewater (TW) – and one conventional freshwater source (FW). Fruit and water chemical composition and fruit quality were evaluated also using a multivariate analysis. The effect on soil chemical fertility was also investigated. As a consequence of various water sources with different nutrient loads, soil nutrient availability, plant uptake and fruit quality were significantly affected by the water source supplied. Plots irrigated with unconventional waters (LW, TW and SW) showed positive impacts on fruit quality (e.g., soluble solids and acidity) and negative nutritional aspects. These results could be attributed to higher soil pH (with lower micronutrients availability) and high concentration of N and K in unconventional wastewater sources. The results obtained with principal component analysis suggested us that water, enriched with mineral nutrients, may affect fruit quality; in our study, a lower fruit firmness while higher h° value and total soluble solids of fruits were observed, indicating an earlier ripening. Further studies are needed in order to understand better the long-term effect of municipal wastewater on nectarine orchard. [ABSTRACT FROM AUTHOR]

Urban agriculture is increasing in both developing and developed countries. In spite of its multiple benefits, urban agriculture can cause unwanted aspects such as environmental damage and health risks to consumers. This work was carried out in a social garden project developed by the Polytechnic Institute of Bragança, Portugal. It checked if cropping practices were environmentally sound and monitored the quality of the edible vegetables, in particular their concentration of trace metals. Bragança is a small city of 25,000 inhabitants located in Northeastern Portugal. In this study the plant nutritional status and the inorganic nitrogen (N) levels in the soil as indirect indicators of the risk of N loss to the environment; and the concentrations of trace metals in the soil and plant tissues as a measure of the exposure of gardeners to trace metals were studied. The results showed the existence of low leaf N concentrations, often close to the deficiency range of the respective species, and also low inorganic N levels in the soil during the winter, suggesting reduced risks of nitrate leaching and denitrification. Trace metal concentrations were low in the soils when compared with the limits set by national and international legislation. As a result, the content of trace metals in edible plant parts was also low. The positive results found in this urban agriculture project might be due to its organic farming basis and to the absence of major sources of pollution in the vicinity of the gardens. This information is useful to local gardeners, since they can trust the products they take home, but also to other urban agriculture projects in even more populated cities. [ABSTRACT FROM PUBLISHER]

The main aim of the present study was to evaluate the influence of the chemical composition of a nutrient solution (NS I, NS II), seed inoculation with Effective Microorganisms (EM), and assimilation illumination (AI) of plants on the growth, development and nutritional status of lettuce (Lactuca sativa L.) in hydroponic cultivation and microbiological changes in the medium. The measurements were as follows: quantity of leaves per plant (LQ), surface area of the biggest leaves of plants (SBL), relative chlorophyll content (SPAD units), total fresh weight (TFW), total dry weight (TDW), percentage (%) of dry matter (% DM), chemical composition of leaves, nutrient uptake (N, P, K, Ca, Mg, Na) of the aboveground parts of the plant. It was shown that the simultaneous inoculation of seeds with EM and application of NS II had an effect on improving seed germination (1st–5th day after sowing), but a significantly positive influence of NS I on seed germination was found from the 5th to 9th day. The application of NS II and EM-A had a positive influence on the development of leaves on the plant. The chemical composition of the nutrient solution was found to have a significant effect on the biometrical parameters of plants. The use of supplemental lighting in cultivation of lettuce affected positively both the growth and development of plants. The chemical composition of the nutrient solution significantly modified the macronutrient nutrition status of plants, while the illumination of plants only in case of phosphorus – but at the same time it had a significant influence on the uptake of all nutrients by the plant. The influence of EM was not proved. The microbiological analysis showed a significant influence of the chemical composition of nutrient solutions on the changes in the numbers of the analyzed groups of microorganisms, showing an increase in their numbers in nutrient solutions with higher contents of chemical elements. However, there were no significant changes in the number of microorganisms relative to the treatment with assimilation illumination and to that of seed inoculation with EM solutions.

We evaluated the effects of the addition of two types of spent mushroom substrate ( SMS), SMS from an Agaricus bisporus crop ( SMS1) and a mixture of SMSs from an A. bisporus crop and a Pleurotus crop (50% v/v each) ( SMS2), on the characteristics of a calcareous clayey-loam soil and the yield and nutritional status of lettuce ( Lactuca sativa L.), relative to crops receiving mineral fertilizer (M) and a control (C) without amendment. The application of SMS, especially SMS1, improved soil fertility compared with C and M soils. Moreover, the use of these organic substrates as soil amendments did not harm the plants and gave yields similar to that obtained with mineral fertilizer. The nutritional contents of the lettuce plants were greater than or similar to those of the plants from treatment C or M, except for the plant tissue concentrations of K, Fe and Zn, which were significantly reduced by SMS application. However, this latter fact did not reduce the lettuce yield in the amended soils. Therefore, the use of SMSs as organic amendments contributes to residue utilization, in an environmentally friendly way, and to improved soil fertility and crop yield. [ABSTRACT FROM AUTHOR]

Foliar urea application provides an alternative strategy for minimizing the risk of nitrogen (N) over-fertilization in green tea (Camellia sinensisL.) production. Solution and pot experiments were conducted with the objective to evaluate the utilization efficiency of foliar applied urea and the impact of plant nitrogen (N), potassium (K), magnesium (Mg) and sulfur (S) nutritional status. In the solution experiment, the dynamic absorption and translocation of foliar N was followed by scheduled samplings at 2 and 6 h, 1, 2, 3, 7 and 13 d after application. In the pot experiment, foliar urea-N absorption was measured for tea plants supplied with adequate nutrients (Control, CK) or low levels of respective nutrients (–N, –K, –Mg, and –S) in soil. The results showed that foliar-15N uptake rate was the highest within the earliest 6 h and the15N amount in treated leaves reached a maximum within 2 d after application in the solution experiment. The absorbed15N was mainly transported to young shoots, and the export rate became significant after 1 d. The total15N absorption in plants increased significantly within 2 d and increased slightly but constantly afterwards until 13 d. In the pot experiment, the low supply of nutrients except S significantly decreased their concentrations in mature leaves. The Ndffvalues in urea-treated leaves and young shoots were 8.1–16.4% and 7.1–19.2%, respectively, and were the highest in the –N treatment compared to the other treatments, suggesting the most remarkable contribution of foliar N application to the N status of –N plants. Low N (–N) supply reduced the total15N absorption and its allocation to young shoots. Low K (–K) supply significantly diminished the15N amount in young shoots without affecting the total absorption. Total15N absorption in tea plants was decreased by low S (–S) but unaffected by low Mg (–Mg) status. The amount of15N in the young shoots correlated closely (r = 0.94, p < 0.001) with its biomass and also with the biomass of whole above-ground plants, to a lesser extent (r = 0.51, p < 0.05). It was concluded that foliar urea-N was rapidly absorbed and exported mainly to the young shoots, representing the major sink. The utilization efficiency of foliar-N was reduced by depleted N, K and S nutritional status which weakened the N sink strength resulting from poor young shoot growth. [ABSTRACT FROM AUTHOR]

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Abstract: Efficient use of fertilizers is a main goal that research in agriculture shall address. Dynamic fertilization management is a way of bringing nutrients to the plant when they are crucial for its development. However, destructive measurements of crop nitrogen status are still too costly and time consuming to justify their use, and the implementation of methodologies based upon non-destructive, quick and easy to use tools for plant nutritional status monitoring appears as an appealing opportunity. In this paper vegetation indices based on crop reflectance through the use of a multispectral radiometer (MSR-87, Cropscan Inc.) are compared. Results from three years of experimentation are provided in order to evaluate (a) relations existing between several vegetation indices and both leaf chlorophyll and nitrogen content; (b) the ability of the tool to respond to different nutrient supply and/or (c) to predict yield. A methodological approach for the definition of the most reliable index is proposed and the adopted procedure allows to define the NIR/R560, even with some degrees of incertitude, as the most suitable index for the evaluation of tomato crop nutritional status. [Copyright &y& Elsevier]