Search Results (28)

The N fertilization to reach high cranberry (Vaccinium macrocarpon) yields resulted in high proportions of soft berries. Our objective was to define the mineral nutrient balance of cranberry to reach a high yield of firm berries. The database comprised 393 observations on cv. ‘Stevens’. Berries were analyzed for total S, N, P, K, Ca, Mg, B, Cu, Zn, Mn, Fe, Al, and Si. Random Forest and XGBoost machine learning models were run to predict yield and firmness classes using raw concentrations, centered log ratios (clr) accounting for nutrient interactions, and weighted log ratios (wlr) that also considered the importance of each dual interaction. The wlr returned the most accurate models. The wlr standards elaborated from the high-yielding and nutritionally balanced subpopulation most often differed between the high-yield class and the high-firmness class. The wlr Cu level was significantly (p ≤ 0.01) too high to reach the high-yielding class in the nutritionally imbalanced subpopulation. There was excessive Al and shortage of Si and Mg to reach high berry firmness in the nutritionally imbalanced subpopulation (p ≤ 0.01), indicating the large influence of soil genesis on berry firmness. Despite statistical evidence, cranberry response to Al and Si corrective measures should be tested to elaborate site-specific recommendations based on soil and tissue tests. Full article

As the global food crisis worsens, enhancing crop yields on saline–alkali soils has become a critical measure for ensuring global food security. Wheat (Triticum aestivum L.), one of the world’s most important staple crops, is particularly sensitive to phosphorus availability, making appropriate phosphorus fertilization a key and manageable strategy to optimize yield. Although many studies have explored phosphorus fertilization strategies, most have focused on non-saline soils or generalized conditions, leaving a critical gap in understanding how phosphorus application affects wheat yield, soil nutrient dynamics, and nutrient uptake efficiency under saline–alkali stress. Therefore, further investigation is required to establish phosphorus management practices specifically adapted to saline–alkali environments for sustainable wheat production. To address this gap, the experiment was designed with varying phosphorus fertilizer application rates based on P₂O₅ content (0, 60 kg/hm², 120 kg/hm², 180 kg/hm², and 240 kg/hm²), considering only the externally applied phosphorus without accounting for the inherent phosphorus content of the soil. The results indicated that as the phosphorus application rate increased, the wheat yield first increased and then decreased. The highest yield (6355 kg·hm⁻²) was achieved when the phosphorus application rate reached 120 kg/hm², with an increase of 47.2–63.5% compared to the control (no fertilizer). Similarly, biomass, thousand-grain weight, and the absorption of nitrogen, phosphorus, and potassium in both straw and grains exhibited the same increasing-then-decreasing trend. Mechanistic analysis revealed that phosphorus fertilization enhanced soil alkali–hydrolyzable nitrogen, available phosphorus, and available potassium, thereby promoting nutrient uptake and ultimately improving grain yield. The innovations of this study lie in its focus on phosphorus management specifically under saline–alkali soil conditions, its integration of soil nutrient changes and plant physiological responses, and its identification of the optimal phosphorus application threshold for balancing yield improvement and nutrient efficiency. These findings provide a scientific basis for refining phosphorus fertilization strategies to sustainably boost wheat productivity in saline–alkali environments. Full article

The production of fruit crops plays a vital role in the agricultural sector, contributing significantly to the social and economic development of rural communities. In Brazil, fruit production is diverse due to favorable edaphoclimatic conditions, with avocado (Persea americana Mill.) emerging as an important crop. Its production continues to expand in both cultivated areas and yield, making it a key export to non-producing countries. However, despite its importance, nutritional management information, crucial for achieving high yields, remains limited. Current guidelines on nutrition monitoring are outdated, general, and based on data from other countries with different edaphoclimatic conditions, making them not directly applicable to Brazilian orchards. Furthermore, outdated nutritional information becomes less reliable over time, as climate change alters soil conditions and crop nutrient concentrations and requirements, reinforcing the need for the establishment of up-to-date and specific nutritional information. This study aimed to establish nutritional standards for ‘Hass’ avocado production using the Diagnosis and Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis (CND) methodologies, and to define sufficiency ranges (SRs) and Critical Levels (CLs) for both macronutrients (N, P, K, Ca, Mg, and S) and micronutrients (B, Cu, Fe, Mn, and Zn). The analyses were based on yield (t ha⁻¹) and leaf nutrient content data from commercial orchards, with datasets divided into younger (4–9 years) and older (10–26 years) plant groups. The DRIS effectively established nutritional standards for younger plants, explaining 11% of yield variation through nutritional balance. CND, in turn, was effective for both groups, accounting for 14% of yield variation and outperforming DRIS in associating nutritional status with productivity. SRs and CLs for ‘Hass’ avocado production were defined using both DRIS and CND. Together, these indices and diagnostic parameters offer valuable tools for enhancing nutritional monitoring and fertilization strategies in Brazil. Notably, SRs and CLs varied according to plant age. Full article

Nitrogen (N) is an essential nutrient for crop growth, as N fertilizer application regulates crop nitrogen uptake, affecting leaf photosynthetic rates, crop growth, and yield formation. However, both N deficiency and excess can reduce corn yields. Hence, optimizing the N fertilizer application strategy is crucial for crop production. In this study, a field plot trial with five N fertilization application strategies was conducted in the maize field from 2021 to 2022 in the Ningxia Yellow Irrigation District, Northwest China. These strategies contain zero N application rates (CK, 0 kg ha⁻¹), the farmer practical N fertilizer application strategy (FP, 420 kg ha⁻¹), the optimized N fertilizer application strategy (OPT, 360 kg ha⁻¹), organic fertilizer and chemical fertilizer combination application (ON, 300 kg ha⁻¹), and controlled-release N fertilizer and 33 urea application (CN, 270 kg ha⁻¹). The maize yield and N balance under each treatment were investigated to propose the optimized N application strategy. The results showed that the CN treatment’s grain yield (15,672 kg ha⁻¹) was the highest in both years, which was 109.97% and 8.92% higher than the CK and FP treatments, respectively. The apparent utilization rate and partial productivity of N fertilizer decreased with the increase in the N application rate. Also, the apparent utilization rate of N fertilizer in CN was 23.02%, 19.41%, and 13.02% higher than the FP, OPT, and ON, respectively. Applying controlled-release urea and organic fertilizers improved the physical and chemical properties of the soil, increased the organic matter content and soil fertility, and ultimately increased the spring maize yield. Meanwhile, the TN, NO₃⁻-N, and NH₄⁺-N concentrations in leaching water significantly correlated with the N application rate. With the extension of the maize growth period, the concentrations of TN, NO₃⁻-N, and NH₄⁺-N in leaching water gradually decreased. The N leaching amount in FP was the highest, while the CN was the lowest. The NO₃⁻-N is the primary N leaching form, accounting for 46.78~54.68% of the TN leaching amount. Compared with the CN, the ON significantly increased the inorganic N content in the 0–40 cm soil layer, and it reduced the residual inorganic N content below 40 cm soil depths compared with FP and OPT treatments. Considering the relatively high spring maize yield and N utilization efficiency, as well as the relatively low N leaching amount and soil inorganic N residues, the ON and CN treatments with 270–300 kg ha⁻¹ N application rate were the optimized N application strategies in the spring maize field in the study area. Full article

The cultivated land in the black soil of Northeast China (BSNC), due to long-term high-input and high-output utilization, is facing a series of challenges such as soil erosion, compaction, and nutrient loss. However, the existing cultivated land quality evaluation (CLQE) lacks regional specificity, making it difficult to accurately reflect the cultivated land quality (CLQ) characteristics across different areas. Therefore, this study proposes a comprehensive evaluation framework that integrates both cultivated land functionality and degradation risk, establishing an assessment system consisting of 18 indicators to comprehensively evaluate the CLQ in the BSNC from multiple perspectives. The results indicate that the CLQ in the BSNC exhibits a declining trend from north to south, with second- and third-grade land dominating, accounting for 75.68% of the total cultivated land area. The overall cultivated land functionality increases from west to east, with the Liaohe Plain Region (LHP) performing the best. Low-risk cultivated land is primarily concentrated in the Songnen Plain Region (SNP) and the Western Sandy Region (WS), covering 38.55% of the total cultivated land area. Additionally, this study finds a trade-off between the primary productivity function and the resource utilization efficiency function across different regions, while a synergistic relationship is observed between resource utilization efficiency and soil nutrient maintenance functions. This research emphasizes the necessity of balancing productivity and ecological protection to achieve the sustainable and efficient use of the BSNC. Full article

Efficient management of soil nutrients is essential for optimizing crop production, ensuring sustainable agricultural practices, and addressing the challenges posed by population growth and environmental degradation. Smart agriculture, using advanced technologies, plays an important role in achieving these goals by enabling real-time monitoring and precision management of nutrients. In open-field soil cultivation, spatial variability in soil properties demands site-specific nutrient management and integration with variable-rate technology (VRT) to optimize fertilizer application, reduce nutrient losses, and enhance crop yields. Hydroponic solution cultivation, on the other hand, requires precise monitoring and control of nutrient solutions to maintain optimal conditions for plant growth, ensuring efficient use of water and fertilizers. This review aims to explore recent trends in soil and solution nutrient sensing technologies for open-field soil and facilitated hydroponic cultivation, highlighting advancements that promote efficiency and sustainability. Key technologies include electrochemical and optical sensors, Internet of Things (IoT)-enabled monitoring, and the integration of machine learning (ML) and artificial intelligence (AI) for predictive modeling. Blockchain technology is also emerging as a tool to enhance transparency and traceability in nutrient management, promoting compliance with environmental standards and sustainable practices. In open-field soil cultivation, real-time sensing technologies support targeted nutrient application by accounting for spatial variability, minimizing environmental risks such as runoff and eutrophication. In hydroponic solution cultivation, precise solution sensing ensures nutrient balance, optimizing plant health and productivity. By advancing these technologies, smart agriculture can achieve sustainable crop production, improved resource efficiency, and environmental protection, fostering a resilient food system. Full article

The present study reviews leachate models useful for proactive and rehab actions to safeguard surface and subsurface soft water, which have become even more scarce. Integrated management plans of water basins are of crucial importance since intensively cultivated areas are adding huge quantities of fertilizers to the soil, affecting surface water basins and groundwater. Aquifers are progressively being nitrified on account of the nitrogen-based fertilizer surplus, rendering water for human consumption not potable. Well-tested solute leaching models, standalone or part of a model package, provide rapid site-specific estimates of the leaching potential of chemical agents, mostly nitrates, below the root zone of crops and the impact of leaching toward groundwater. Most of the models examined were process-based or conceptual approaches. Nonetheless, empirical prediction models, though rather simplistic and therefore not preferrable, demonstrate certain advantages, such as less demanding extensive calibration database information requirements, which in many cases are unavailable, not to mention a stochastic approach and the involvement of artificial intelligence (AI). Models were categorized according to the porous medium and agents to be monitored. Integrated packages of nutrient models are irreplaceable elements for extensive catchments to monitor the terrestrial nitrogen-balanced cycle and to contribute to policy making as regards soft water management. Full article

Excessive application of fertilizers in drip-irrigated wheat production can suppress yields, lower nutrient utilization efficiency, and lead to economic and environmental issues such as nitrogen residues in the soil. Based on a recommended fertilizer application (RF) strategy that takes into account target yield and nutrient requirements, this study explores the responses of wheat plant traits, changes in topsoil and subsoil nutrients, fertilizer utilization, and economic benefits under this strategy. From 2022 to 2023, a field experiment was conducted in a typical oasis spring wheat production area at the northern foot of the Tianshan Mountains in Xinjiang. The treatments included no fertilizer control (CK), the farmer’s conventional practice (FP), recommended fertilizer (RF), RF with nitrogen omission (RF-N), phosphorus omission (RF-P), and potassium omission (RF-K). The results showed that compared with FP, the RF reduced 91 kg N ha⁻¹ (30.3%) and 33 kg P₂O₅ ha⁻¹ (24.8%) in 2022, and 69 kg N ha⁻¹ (23.0%) and 2 kg P₂O₅ ha⁻¹ (1.5%) in 2023. The effect in 2023 was better; RF also decreased the NO₃⁻¹-N residue in the 0–100 cm soil layer by 40.1 kg N ha⁻¹ compared with FP, with no significant difference in wheat grain yield (RF: 5382.9 kg ha⁻¹) or economic benefit (RF: USD 1613.1 ha⁻¹). Furthermore, there were no significant differences between RF and FP in pre-anthesis NP transport or post-anthesis NP accumulation; however, RF significantly increased pre-anthesis potassium transport volume (15.8%) and transport rate (12.5%). RF led to a 16.3% increase in nitrogen utilization efficiency (NUE), while there was no significant difference in phosphorus utilization efficiency (PUE) compared with FP. The fertilizer yield effect for RF was evaluated as N > P > K. Correlation analysis indicated that grain yield was significantly positively correlated with pre-anthesis NPK transport and post-anthesis NP accumulation. It was also positively correlated with organic matter, alkali-hydrolyzed nitrogen, and Olsen-P content in both the topsoil (0–20 cm) and subsoil (20–40 cm), but not with available potassium in the soil. Therefore, conducting soil tests and determining fertilizer recommendations based on the proposed RF method at harvest can reduce fertilizer usage and achieve a balance between the conflicting objectives of environmental protection, increased crop yields, nutrient utilization efficiency, and improved economic benefits in oasis agricultural areas facing excessive fertilizer application. Full article

In the cultivation of crops in recent times, in addition to taking care of the balanced supply of nutrients to plants and the protection of soil resources, it is also important to take into account the non-productive factor by implementing production systems based on balanced fertilisation. The aim of this study was to demonstrate the effect of soil kind and the application of a new fertiliser based on a urea and ammonium nitrate solution with potassium thiosulphate (UAN-KTS) on the yielding and biometric characteristics of spring wheat, spring rape, and maize to determine the optimal N:K:S ratio. An increase in the soil kind increased the weight of 1000 spring rape seeds, the yield of maize fresh matter, a reduction in the height of spring wheat and maize plants, a reduction in the yield of spring wheat grains and straw, and the yield of the fresh and dry matter of spring rape straw. A higher nitrogen dose promoted the growth of spring rape at the later growing stage and maize and had a positive effect on the yield of spring wheat grains and straw, spring rape seeds and straw, and the above-ground parts of maize. The application of potassium fertilisers caused a significant increase in the spring rape plant height, an increase in the yield of spring wheat grains and straw and spring rape seeds and straw, the above-ground parts of maize, a reduction in the plant height at the beginning of the spring wheat growing period, and a reduction in the weight of 1000 spring rape seeds (only on the soil with rich quality). The fertiliser with the N:K₂:S₂ ratio had a particularly favourable effect on the yielding of spring wheat. In the cultivation of maize, the same effect was most often obtained under the influence of fertiliser in the ratio of N:K₁:S₁ on the weaker soil fertilised at the same time as a higher dose of nitrogen (N 1) and N:K₂:S₂ (in other cases). In the case of spring rape, generally, fertiliser with N:K₁:S₁ was the strongest, although, in some objects, a higher yield was achieved under the influence of N:K₂:S₂. The existence of statistically confirmed correlations (expressed as the percentage of the variability observed) between the soil kind and the fertilisers applied and the yielding and biometric characteristics of the plants were observed. Full article

Olive tree growing (Olea europaea L.) has considerably increased in the last decades, as has the consumption of extra virgin olive oil in the world. Precision agriculture is increasingly being applied in olive orchards as a new method to manage agronomic variability with the aim of providing individual plants with the right input amount, limiting waste or excess. The objective of this study was to develop a methodology on a GIS platform using GEOBIA algorithms in order to build prescription maps for variable rate (VRT) nitrogen fertilizers application in an olive orchard. The fertilization plan was determined for each tree by applying its own nitrogen balance, taking into account the variability of nitrogen in soil, leaf, production, and actual biometric and spectral conditions. Each olive tree was georeferenced using the S7-G Stonex instrument with real-time kinematic RTK positioning correction and the trunk cross section area (TCSA) was measured. Soil and leaves were sampled to study nutrient variability. Soil and plant samples were analyzed for all major physical and chemical properties. Spectral data were obtained using a multispectral camera (DJI multispectral) carried by an unmanned aerial vehicle (UAV) platform (DJI Phantom4). The biometric characteristics of the plants were extracted from the achieved normalized vegetation index (NDVI) map. The obtained prescription map can be used for variable rate fertilization with a tractor and fertilizer spreader connected via the ISOBUS system. Using the proposed methodology, the variable rate application of nitrogen fertilizer resulted in a 31% reduction in the amount to be applied in the olive orchard compared to the standard dose. Full article

(1) Background: Soil organic carbon (SOC) in agricultural soils plays a crucial role in mitigating global climate change but also, and maybe more importantly, in soil fertility and thus food security. Therefore, the influence of contrasting cropping systems on SOC not only in the topsoil, but also in the subsoil, needs to be understood. (2) Methods: In this study, we analyzed SOC content and δ¹³C values from a crop rotation experiment for biogas production, established in southern Germany in 2004. We compared two crop rotations, differing in their proportions of maize (0 vs. 50%) and perennial legume–grass leys as main crops (75 vs. 25%). Maize was cultivated with an undersown white clover. Both rotations had an unfertilized variant and a variant that was fertilized with biogas digestate according to the nutrient demand of crops. Sixteen years after the experiment was established, the effects of crop rotation, fertilization, and soil depth on SOC were analyzed. Furthermore, we defined a simple carbon balance model to estimate the dynamics of δ¹³C in soil. Simulations were compared to topsoil data (0–30 cm) from 2009, 2017, and 2020, and to subsoil data (30–60 cm) from 2020. (3) Results: Crop rotation and soil depth had significant effects, but fertilization had no effect on SOC content and δ¹³C. SOC significantly differed between the two crop rotations regarding δ¹³C in both depths but not regarding content. Annual enrichment in C₄ (maize) carbon was 290, 34, 353, and 70 kg C ha⁻¹ per maize year in the topsoil and subsoil of the unfertilized and fertilized treatments, respectively. These amounts corresponded to carbon turnover rates of 0.8, 0.3, 0.9, and 0.5% per maize year. Despite there being 50% maize in the rotation, maize carbon only accounted for 20% of the observed carbon sequestration in the topsoil. Even with pre-defined parameter values, the simple carbon model reproduced observed δ¹³C well. The optimization of model parameters decreased the carbon use efficiency of digestate carbon in the soil, as well as the response of belowground carbon allocation to increased aboveground productivity of maize. (4) Conclusions: Two main findings resulted from this combination of measurement and modelling: (i) the retention of digestate carbon in soil was low and its effect on δ¹³C was negligible, and (ii) soil carbon inputs from maize only responded slightly to increased above-ground productivity. We conclude that SOC stocks in silage maize rotations can be preserved or enhanced if leys with perennial crops are included that compensate for the comparably low maize carbon inputs. Full article

Iron chlorosis is common in vineyards grown on calcareous soils, and consists of a chlorophyll deficiency caused by a disorder in iron nutrition. It is manifested by interveinal yellowing of the youngest leaves and decreased growth and production. Most of the vineyards in Spain are planted on calcareous soils, so iron chlorosis is frequent, even in tolerant rootstocks. In the case of Spain, Tempranillo accounts for 20.8% of the total Spanish wine area, with this red variety being the most planted. The study of iron chlorosis and the availability of nutrients is essential for improving the qualitative balance of the wine, as it is one of the most representative in our country. The aim of this work was to evaluate how carbonated irrigation modifies soil pH and increases the absorption of nutrients, as well as to assess the impact of chlorosis on the physiology of the variety and the composition of the grape. In the first instance, a test was carried out on bare soil of calcareous composition, evaluating three different levels of carbonated water, and seeing what response it gave to the pH level. The result showed that the dose of 400 ppm of CO₂ provided the optimal pH. Subsequently, in a potted soil, the dose of 400 ppm of CO₂ was evaluated on the variety cv. Tempranillo, in three different compositions of calcareous soil. Results showed that carbonated irrigation increased the levels of chlorophyll impacting on primary metabolism (acids and sugar), plant growth, and higher crop yield, improving the optimal grape ripeness. Given that irrigation with 400 ppm CO₂ increased the ability to control ferric chlorosis, this strategy could be an easy-to-use alternative to iron-based chelates for preventing Fe deficiency in the grapevine as well as moderating the different levels of iron chlorosis. This strategy could be an alternative to the use of synthetic Fe chelates as EDTA or o,o-EDDHA for preventing Fe chlorosis in susceptible Tempranillo (Vitis vinifera L.) vineyard in calcareous soils, with less of a risk to the environment. Full article

Organic matter (OM) and nutrient nitrogen (N) play vital roles in the fertility and production of soil in accordance with goals of efficient environmental protection. This study aimed to show the extent to which N delivery can contribute to improving nitrogen fertilizer requirements (NFR) through comparative analysis of OM and N. Systems determining the NFR in agricultural practices have thus far been challenged to estimate the annual rate of mineralization of the soil. OM and N turnover was investigated through an available evaluation consisting of 546 representatively distributed permanent test and observation plots (TP) of the German Federal State of Saxony farms. A solid database of at least 10-year field plot card records from 2001 to 2010 was selected for the analysis. A program (BEFU) widely used in agricultural practice, along with the simplified process model CCB, were applied. For the calculation of the amount of mineral N fertilizers used, the results of three different methods for determining the NFR were compared with each other. The determination of the farmers’ demand (=actual condition of the TP) with a mean value of 132 kg N ha⁻¹ did not show a large difference between the calculated values with 137 kg N ha⁻¹ by the BEFU program. Based on the available results for the most important crop species cultivated in Saxony, there were clear differences in the considerations of the N delivery from the soil. The BEFU program was able to calculate an average N delivery of 17 kg N ha⁻¹ from tabulated data, whereas with the CCB process model, 66 kg N ha⁻¹ of mineralization was determined with a distinct higher deviation by taking into account the 10-year field histories. Using the N delivery of the TP by the CCB model, a clear reduction of the mean N fertilization level, to about 80 kg N ha⁻¹, was therefore achieved. These differences were particularly large for TP with organic fertilization (livestock), at a relatively low N fertilization level, and for certain crop species. With a high standard deviation, the average savings potential of mineral N fertilizers was 52–57 kg N ha⁻¹. After including the corrected values for the N mineral fertilization, a decrease in the N balances by an average of 20–25 kg N ha⁻¹ was ultimately achieved. In particular, the heavily oversupplied plots with D and E classification decreased by approximately 50%. The results of our study demonstrate clear improvements; therefore, increased efforts should be made in the future to optimize the determination of NFR using applicable methods that consider N mineralization in agricultural practice and consultation. Full article

Phosphorus (P) is essential for agriculture; however, local P surpluses can have adverse environmental effects, such as eutrophication. Optimal P fertiliser use, therefore, means balancing these effects. Although P fluxes from soil to plants are key research areas, little is known about on-farm use of P fertilisers. As, typically, not all fields or crops are treated with P annually, the transferability of measurements for other nutrients, such as nitrogen, appears limited. This study aims to close this knowledge gap. On-farm P use was described using the farm records of 50 farms in five regions of northern Germany for the period of 2010 to 2018. All sources for P fertilisation were taken into account as either P mineral, P organic or P total. Two indicators for on-farm P use were suggested: frequency, which gives the percentage of the treated area, and amount, which gives the quantity used per ha of the treated area. The frequency for P total ranged from 55.9% to 93.1% of the total farm area being fertilised. Amounts between 24.8 and 41.6 kg ha⁻¹ P total were applied on the treated area of the farm. The results supported the separation of the quantity and frequency in on-farm P use. No decrease in P use was found during the period investigated. Using mixed models, the results further show that explanatory variables, including the farm characteristics and crop choice, explain the substantial variations in P use. It is recommended for the example of Germany to establish an official digital database for P fertilisers that can be updated professionally and is mandatory for all documentation on P use. Full article

Water reuse via land application is old technology; but the water balance only design approach and practice has not worked well. There are many benefits of water reuse by irrigating crops; however, there are some risks if not designed properly. When the design approach uses a combined water-nutrient-salt balance, the most effective and sustainable, long-term system is achieved. This approach provides a design based on land area requirements, on-site water storage, and economic return from the irrigated crops. The single, most often overlooked step in the water balance is accounting for the water stored in the soil. When spread over large areas, this quantity of water results in considerably less required surface water storage, which saves capital costs. This design approach has been used successfully on multiple sites for over 30 years without failure. Full article