Search Results (4,707)

Straw return plays a vital role in crop yield and sustainable agriculture. Extensive research has focused on the potential to enhance soil fertility and crop yield through straw return. However, the potential impacts of straw return on saline–sodic soils have been relatively neglected due to the unfavorable characteristics of saline–sodic soils, such as high salinity, poor structure, and low nutrient contents, which are not conducive to crop growth. Therefore, a two-year field experiment was conducted to assess the effects of straw management (retention or removal) with nitrogen fertilizers (0, 90, 180, 270, and 360 kg N ha⁻¹) on soil aggregates, soil chemical properties, and rice yields in saline–sodic soil. The results showed that straw return with nitrogen fertilization significantly decreased the soil exchange sodium percentage (ESP) and the percentage and organic carbon contribution of silty clay particles and also significantly increased the soil aggregate stability, organic matter (SOM), and percentage and organic carbon contribution of macroaggregates. However, there was no significant difference between 270 kg N ha⁻¹ and 360 kg N ha⁻¹ for all soil indicators under straw return. Straw return significantly increased rice grain yield by 5.77% (two-year average) compared to straw removal. The highest grain yield of 8.01 t ha⁻¹ (two-year average) was obtained from straw return combined with 270 kg N ha⁻¹. However, since this experiment was conducted for only two years, the positive effects of long-term straw return on soil and rice yield could have been greater. Therefore, the application of 270 kg N ha⁻¹ in the early stages of straw return is a promising management practice for improving saline–sodic soils and increasing rice yields. Full article

Durum wheat is essential for global food security. Nevertheless, its cultivation is susceptible to hazards, including unpredictability in yield and grain quality. This systematic review and bibliometric analysis identify factors influencing durum wheat yield and quality, assessing the degree of control farmers have over these factors. The goal is to understand their impact on production risks. Peer-reviewed studies in English from 1990 to April 2024 that focused on the yield or quality of durum wheat were included, while those lacking specific data or not peer-reviewed were excluded. Data were acquired via the Web of Science (WoS), with the concluding search conducted in April 2024. Results were synthesized from 2131 studies selected from an initial pool of 5159, using a bibliometric approach to categorize findings into standard, biotic, abiotic, and other factors. Analysis revealed that practices like irrigation and nitrogen fertilization improve yields, while genetic advancements boost stress resilience. These insights support targeted agronomic strategies. Despite potential biases and inconsistencies, the review underscores key strategies to enhance durum wheat risk management and bolster food security. This study was funded by the Italian Ministry of University and Research (CURSA, D.I.Ver.So.) and PRIN—2020 Call. Full article

Coastal saline cropland ecosystems are becoming increasingly vital for food security in China, driven by the decline in arable land and the growing demand for resource-intensive diets. Although developing and utilizing saline land can boost productivity, it also impacts greenhouse gas (GHG) emissions. This study uses the Yellow River Delta as a case study to analyze the spatial-temporal patterns of carbon footprints in saline croplands from 2001 to 2020 and their correlations with climate factors, cropland management scale, and agricultural mechanization. The results reveal that agricultural production in this region is characterized by high inputs, emissions, and outputs, with carbon emission efficiency improving significantly due to a reduction in net carbon emissions. Major sources of carbon emissions include electricity, chemical nitrogen fertilizers, nitrogen input, and straw return, which together account for 65.06% of total emissions. Based on these findings, three key principles have been proposed for policy recommendations to enhance carbon emission efficiency. First, adopt tailored strategies for regions with different salinization levels. Second, strengthen cropland drainage infrastructure to mitigate the adverse effects of heavy rainfall. Third, expand the scale of cropland management through land transfers and promote agricultural mechanization. These insights offer valuable guidance for mitigating GHG emissions in coastal saline cropland ecosystems. Full article

As the global demand for high-quality tea increases, adopting sustainable agricultural practices is crucial to maintaining environmental health and improving crop productivity. Employing organic fertilizers has the potential to boost agricultural output and improve soil health, as well as curb the spread of pests and diseases. The purpose of this survey was to determine the impact of a range of organic fertilizer mixtures on both tea plants and rhizosphere soil characteristics in tea plantations. This study investigated the response of Jin Guanyin tea (Camellia sinensis L.) plants to various organic fertilizer ratios: 2/3 chemical fertilizer + 1/3 organic fertilizer (JTC), 1/2 chemical fertilizer + 1/2 organic fertilizer (JHOC), 1/3 chemical fertilizer + 2/3 organic fertilizer (JTO), and organic fertilizer only (JOF), with chemical fertilizer alone (JCF) as the control. The experiment was conducted in Xingcun Town, Wuyishan, Fujian Province, China, on 13 October 2021. Key metrics measured included tea plant growth indicators, soil physicochemical properties, enzyme activities, and microbial functional diversity. Results show that JTC and JTO produce the largest leaf area and bud weight, significantly surpassing those in JCF. JCF demonstrated the longest new tip length and highest bud density, while JHOC achieved the highest chlorophyll content, significantly exceeding JCF. Soil analysis revealed that total nitrogen, available nitrogen, organic matter, and pH were highest in JOF, significantly overtaking JCF. Conversely, total phosphorus, available potassium, and available phosphorus levels were highest in JCF. JHOC also had the highest total potassium content compared to JCF. Soil enzyme activity assessments showed that polyphenol oxidase and urease activities peaked in JTC, significantly exceeding those in JCF. JHOC exhibited the highest acid phosphatase activity, while JTO exhibited the highest protease activity. Catalase activity was highest in JOF, both significantly surpassing JCF. Microbial functional diversity analysis indicated that combined organic fertilization improved soil microorganisms’ utilization of carbon sources, significantly enhancing the Shannon diversity index and evenness. Key carbon sources identified included $\mathsf{\alpha }$-cyclodextrin, D-galacturonic acid, and 4-hydroxy benzoic acid. Overall, JHOC emerged as the optimal fertilization strategy, yielding superior growth indicators, enhanced soil physicochemical properties, increased enzyme activity, and improved microbial functional diversity compared to JCF. This study has important value for guiding the rational application of fertilizers in tea gardens, improving the soil environment of tea gardens, enhancing the quality of tea leaves, and achieving sustainable tea production. Full article

The rapid increase in fertilizer use has led to the degradation of soil quality, nutrient imbalances, reduced biodiversity, and soil compaction. To address these challenges, hybrid soybeans with efficient biological nitrogen fixation capabilities and broad environmental adaptability were selected as green manure to reduce fertilizer application, thereby improving soil fertility and structure. This study utilized the varieties “Forage Soybean S001” (S001), “Neinong S002 Forage Soybean” (S002), “Mengnong S003 Forage Soybean” (S003), “Mengnong S004 Forage Soybean” (S004), “Mengnong S005 Forage Soybean” (S005), and “Mengnong S006 Forage Soybean” (S006) as green manure materials. The clean tillage (CK) treatment served as the control, ensuring a residue-free soil surface while maintaining consistent practices in soil preparation, irrigation, and field management across all treatments. Field planting of green manure and subsequent crops was conducted at the M-Grass Ecology and Environment (Group) Company’s experimental site in Hohhot in early May of 2023 and 2024. The plots each measured 20 m², with three replications arranged in a randomized block design. A combination of field experiments and laboratory analyses was utilized to investigate the effects of incorporating various hybrid soybean varieties as green manure on soil nutrient levels, soil enzyme activity, soil microbial communities, and the subsequent growth of oats. The results indicated that incorporating various hybrid soybean varieties as green manure into the soil significantly improved soil nutrient levels and enzyme activity. The diversity and richness of soil bacterial communities increased significantly, accompanied by alterations in community structure and composition. These changes enhanced soil fertility and optimized the microbial community structure, promoting the growth of subsequent crops. Among all the treatments, S001 and S004 were particularly effective in enhancing the soil environment, indicating their potential as superior green manure resources for broader application. Full article

Biochar has gained considerable attention as a sustainable soil amendment due to its potential to enhance soil fertility and mitigate nitrogen (N) losses. This study aimed to investigate the effects of biochar application on the abundance of key N-cycling genes in Mollisol and alkaline soils, focusing on nitrification (AOA, AOB, and nxrB) and denitrification (narG, norB, and nosZ) processes. The experiment was conducted using soybean rhizosphere soil. The results demonstrated that biochar significantly altered the microbial community structure by modulating the abundance of these functional genes. Specifically, biochar reduced narG and nosZ abundance in both soil types, indicating a potential reduction in N₂O emissions. In contrast, it promoted the abundance of nxrB, particularly in alkaline soils, suggesting enhanced nitrite oxidation. The study also revealed strong correlations between N-cycling gene abundances and soil properties such as pH, EC (electrical conductivity. Biochar improved soil pH and nutrient availability, creating favorable conditions for AOB and Nitrospira populations, which play key roles in ammonia and nitrite oxidation. Additionally, the reduction in norB/nosZ ratios in biochar-treated soils suggests a shift towards more efficient N₂O reduction. These findings highlight biochar’s dual role in enhancing soil fertility and mitigating greenhouse gas emissions in Mollisol and alkaline soils. The results provide valuable insights into the sustainable management of agricultural soils through biochar application, emphasizing its potential to optimize nitrogen-cycling processes and improve soil health. Further research is needed to explore the long-term impacts of biochar on microbial communities and nitrogen-cycling under field conditions. Full article

Microalgae have gained attention due to their higher reproduction rate and lipid productivity. In particular, various stress conditions lead to an overproduction of lipids in microalgae cells. The study investigated the influence of additional CO₂ introduced with air into the reactor during biomass growth of Chlorella sp. Additionally, increased phosphorus concentration in the medium under stress cultivation (low nitrogen concentration) was examined. The partial pressure of CO₂ and its increased availability to Chlorella sp. in the cultivation medium increased biomass growth (1.4 times) and chlorophyll content (2.5 times) in microalgae cells. A high phosphorus fertilizer significantly increased lipid production under stress conditions with CO₂ supply to 85.2 mg/g (2.6 times) and without CO₂ to 73.8 mg/g (2.2 times). A high concentration of phosphorus in the culture medium stimulated the synthesis of C16:0 (about 38–45%) and C18:1 CIS9 (about 24–30%). The results confirm that the fertilizers can be used as a culture medium to induce stress and stimulate lipid production. Adjusting the composition of the fertilizers and controlling the additional CO₂ supply could prove beneficial to increase the content of the desired fatty acids. Full article

Soil and plant analyzer development (SPAD) value and leaf nitrogen concentration (LNC) based on dry weight are important indicators affecting rice yield and quality. However, there are few reports on the use of machine learning algorithms based on hyperspectral monitoring to synchronously predict SPAD value and LNC of indica rice. Meixiangzhan No. 2, a high-quality indica rice, was grown at different nitrogen rates. A hyperspectral device with an integrated handheld leaf clip-on leaf spectrometer and an internal quartz-halogen light source was conducted to monitor the spectral reflectance of leaves at different growth stages. Linear regression (LR), random forest (RF), support vector regression (SVR), and gradient boosting regression tree (GBRT) were employed to construct models. Results indicated that the sensitive bands for SPAD value and LNC were displayed to be at 350–730 nm and 486–727 nm, respectively. Normalized difference spectral indices NDSI (R497, R654) and NDSI (R729, R730) had the strongest correlation with leaf SPAD value (R = 0.97) and LNC (R = −0.90). Models constructed via RF and GBRT were markedly superior to those built via LR and SVR. For prediction of leaf SPAD value and LNC, the model constructed with the RF algorithm based on whole growth periods of spectral reflectance performed the best, with R² values of 0.99 and 0.98 and NRMSE values of 2.99% and 4.61%. The R² values of 0.98 and 0.83 and the NRMSE values of 4.88% and 12.16% for the validation of leaf SPAD value and LNC were obtained, respectively. Results indicate that there are significant spectral differences associated with SPAD value and LNC. The model built with RF had the highest accuracy and stability. Findings can provide a scientific basis for non-destructive real-time monitoring of leaf color and precise fertilization management of indica rice. Full article

Farmland ammonia (NH₃) volatilization is an important source of NH₃, and the application of chemical fertilizer nitrogen (N) is the main factor affecting NH₃ volatilization. The optimal substitution of chemical fertilizer with organic manure and straw reportedly reduces NH₃ volatilization, while reducing irrigation increases NH₃ volatilization. However, the combined effect of nitrogen fertilizer substitution and reducing irrigation on NH₃ volatilization and the role of microorganisms in this process remains unclear. In a soil column experiment, NH₃ volatilization and microbial composition were measured under both multiple N sources and different irrigation levels by the vented-chamber method and metagenomic sequencing. The results revealed that multiple N sources application reduced cumulative NH₃ volatilization by 16.5–75.4% compared to single chemical fertilizer application, and the decreasing trend of NH₃ volatilization under reduced irrigation conditions was greater. Microorganisms had a more important effect on NH₃ volatilization of reduced irrigation than conventional irrigation. The abundance of nirA, arcC, E3.5.1.49, and E3.5.5.1 (ammonia-producing) genes varied significantly at the two irrigation levels. Overall, multiple N sources could inhibit NH₃ volatilization increasing under reducing irrigation compared to a single chemical fertilizer. Our findings contribute valuable insights into the combined effect of reduced irrigation and multiple N sources on NH₃ volatilization. Full article

The cherry tomato has an important economic value and an increasingly broad market, and the chlorophyll content of cherry tomato leaves can directly reflect the plant’s photosynthetic ability, thus indirectly reflecting its growth status. Therefore, this paper proposes a regression detection method for chlorophyll in cherry tomato leaves by combining machine learning and hyperspectral technology to realize non-destructive, fast, and more accurate detection. Firstly, Moving-Average (MA) preprocessing was chosen as the pretreatment method for this paper, and three regression models of principal component regression (PCR), random forest (RF), and partial least squares regression (PLSR) were established with leaf chlorophyll under different nitrogen concentrations. The CARS_PLSR algorithm has the highest prediction accuracy with accuracy, precision, RMSEC, and RMSEP of 0.8790, 0.9187, 2.9581, and 2.5578, respectively. The study examined the impact of various nitrogen concentrations on the chlorophyll content of cherry tomato leaves, and it was found that the high concentration of nitrogen inhibited the SPAD value of cherry tomato leaves more than that of the low concentration, and the optimal concentration of nitrogen fertilization for tomatoes was 300 mg·L⁻¹. Finally, a regression model was established by using CARS-PLSR combined with the pseudo-color map technology, and a distribution map of chlorophyll content in different SPAD value gradients of cherry tomato leaves was obtained, which could visualize the distribution of chlorophyll and its distribution sites in the leaves and understand the growth status of cherry tomatoes. The distribution of chlorophyll content in different SPAD values of cherry tomato leaves was obtained by using the CARS-PLSR regression model combined with pseudo-color map technology, which can visualize the distribution of chlorophyll in the leaves and the parts of distribution and understand the growth condition of cherry tomatoes. Finally, the optimal model is applied in conjunction with a sprayer to automate fertilizer application. Full article

Oilseed rape is one of the most important oilseed crops, requiring high levels of nitrogen fertilization. Excessive nitrogen use, however, leads to numerous negative environmental impacts, spurring the search for sustainable, environmentally friendly alternatives to reduce reliance on mineral nitrogen fertilizers. One promising approach involves plant-growth-promoting bacteria (PGPB), which can support oilseed rape growth and lessen the need for traditional nitrogen fertilizers. This study evaluates a selected microbial consortium comprising bacterial isolates obtained from soil: Pseudomonas sp. G31 and Azotobacter sp. PBC2 (P1A). The applied PGPB significantly increased seed yield (a 27.12% increase) and, in the initial phase of the study, reduced the ammonium nitrogen content in the soil (a 20.18% decrease). Metataxonomic analyses were performed using Next-Generation Sequencing (NGS) technology by Illumina. Although P1A did not significantly affect alpha diversity, it altered the relative abundance of some dominant soil microorganisms. In the BBCH 75 phase, the P1A consortium increased the abundance of bacteria of Firmicutes phylum, including the genera Bacillus and Paenibacillus, which was considered a beneficial change. In summary, the Pseudomonas sp. G31 and Azotobacter sp. PBC2 consortium increased seed yield and was found to be part of the native rhizosphere community of oilseed rape, making it a promising candidate for commercialization. Full article

The leaching of phosphorus (P), together with nitrogen (N), into deep water and runoff from fields into surface water has caused the dangerous phenomenon of eutrophication, which threatens the Baltic Sea. This process has led to a revision of fertilizer recommendations for farmers in most European countries. The basis for proper recommendations is the determination of soil P using a soil test. There are many different soil tests used in Europe for the determination of plant-available P in soil, which is primarily the result of the different soil conditions in the individual countries. In Poland, two soil P tests are currently used: the Egner–Riehm DL (DL) test and the Mehlich 3 (M3) test. The aim of our study was to determine the extraction efficiency of the DL and M3 tests, to explore the possibility of converting the results of one test to another, and to compare the diagnostic value of the tests. For this purpose, a collection of 237 soil–plant sample pairs was taken from maize fields in Poland. The phosphorus content was determined in all the soil and plant samples, with two methods used in the soil samples: DL and M3. The results of our study show that it is not possible to state unequivocally which test extracts more P from the soil. The extraction efficiency of the tests depends on the specific soil properties, particularly pH and texture. The most reliable conversion of DL test results to M3 is possible for soils that contain a 21–35% fraction characterized by particles less than 0.02 mm in diameter, regardless of soil pH. Furthermore, the DL test has better diagnostic value than M3, especially for alkaline soils. Full article

The degree of proteolytic modification in wheat malts significantly affects their quality, determining their suitability for use in brewing. Nitrogen fertilization at doses of 60 and 80 kg N·ha⁻¹ applied during 3-year field experiments had a positive effect on the content of protein compounds in the analyzed wheat malts. The total protein content of the malts obtained averaged 9.9–10.1% d. m., depending on the cultivar, and from 9.1 to 10.8% dry matter, depending on nitrogen fertilization. The soluble protein content and Kolbach index value were at similar levels (4.60% dry matter and 46.07%, respectively, on average) except for malt obtained from the Elixer cultivar, for which significantly lower values were obtained (by 7.39% and 6.66%, respectively). In contrast, the highest free amino nitrogen value was obtained for malts derived from the Elixer and Gimantis cultivars. The least variation in the quality of malts derived from grains obtained in the three growing seasons during the field experiments was in the cultivar Gimantis. In 2-year commodity field experiments (in commodity farms), under 60 kg N·ha⁻¹ nitrogen fertilization, the cultivar Lawina was characterized by the best indices of the degree of proteolytic modification. Full article

Effective water and fertilizer management is crucial for the forestry production of Pistacia weinmannifolia. This experiment employed an orthogonal design to measure the water potential, anthocyanins, chlorophyll, and photosynthetic parameters of Pistacia weinmannifolia under different water and fertilizer regimes. The effects of different water and fertilizer regimes on the water potential, phenolic compounds, and photosynthetic characteristics of Pistacia weinmannifolia were analyzed. A comprehensive analysis method was used to evaluate and establish the best water and fertilizer regimes system. The results showed that the water and fertilizer regimes increased the water potential, anthocyanins, chlorophyll content, flavonoids, and photosynthesis (p < 0.05). During the mid-growth stage and late mid-stage growth of Pistacia weinmannifolia, the fertilizers with the most significant effects on water potential, chlorophyll, and anthocyanins were nitrogen (N) and phosphorus (P). The supply of a certain amount of N and P had positive effect on water potential, chlorophyll, and anthocyanins. Increasing N content was more effective in improving carboxylation efficiency than increasing P content. The effect of N content on photosynthetic efficiency was greater than that of P content Analyses using the TOPSIS model demonstrate that Pistacia weinmannifolia exhibits superior comprehensive efficiency in water potential, chlorophyll, flavonoid, and anthocyanin content. When applying 0.54 g·plant⁻¹ of pure P and 0.67 g·plant⁻¹ of pure N, with the relative soil moisture content maintained at 85%, the optimal comprehensive benefit for photosynthetic indicators is achieved with 0.34 g·plant⁻¹ of pure P and 0.77 g·plant⁻¹ of pure N, while maintaining the relative soil moisture content at 46.66%. These findings indicate that the water–fertilizer coupling treatment group exhibited improved growth status and photosynthesis. Therefore, the cultivation of Pistacia weinmannifolia should prioritize maintaining a balanced water–fertilizer ratio to optimize resource utilization. Full article

To mitigate the issues of soil quality degradation and environmental pollution caused by excessive fertilizer use in apple orchards, the present study investigated the effects of organic fertilizer substitution combined with chemical nitrogen (N) fertilizer reduction on soil nutrient status, enzyme activity, and microbial communities (bacteria, fungi and archaea) over one year in an apple orchard. Five fertilization treatments were implemented, including 100% chemical fertilizer (CK), 80% chemical fertilizer + 20% liquid humic fertilizer (S1), 60% chemical fertilizer + 40% liquid humic fertilizer (S2), 60% chemical fertilizer + 20% liquid humic fertilizer (S3), and 40% chemical fertilizer + 40% liquid humic fertilizer (S4). Substituting chemical fertilizers with liquid humic fertilizers effectively enhanced the soil organic matter (SOM) content in the topsoil (0–20 cm) for all treatments. Compared to CK, the amounts of available N (NO₃⁻-N and NH₄⁺-N) were decreased in the topsoil and the amounts of total N, total phosphorous and available phosphorous were increased in the subsoil (20–40 cm) for all treatments. The β-diversity of bacterial communities exhibited the highest sensitivity to soil environmental changes, followed by that of archaea, whereas fungi demonstrated the least susceptibility. The higher soil carbon/nitrogen ratio and SOM content in S2 altered the abundance of microorganisms (Proteobacteria, Ascomycota, and Crenarchaeota) that were closely related to the decomposition and mineralization of SOM and N, enhancing the efficiency of SOM decomposition. The activities of sucrase (SUC), urease (UE), and phosphatase were increased, also promoting the conversion efficiency of SOM and improving N fixation and soil fertility. In the organic fertilizer substitution treatments (S1 and S2), the abundance of dominant Actinobacteriota, Ascomycota and Crenarchaeota phyla were increased, as well as the activities of SUC and UE, accelerating the decomposition and mineralization of SOM and improving soil fertility. In the top, organic fertilizer substitution combined with reduced chemical N fertilizer (S3 and S4) treatments increased the abundance of bacteria and fungi. In addition, RDA showed that total potassium content could significantly affect changes in the bacterial and fungal community structure in subsoil. Overall, organic fertilizer substitution enhanced the content of soil available nutrients and improved soil nutrient retention. It is recommended to promote organic fertilizer substitution + chemical N fertilizer reduction (S4) with the supplementation of potassium fertilizer in the subsoil. The findings provide a theoretical basis and practical guidance for improving orchard soil management and achieving sustainable development in the apple industry. Full article