Journal of Soil Science and Plant Nutrition最新文献

Magnesium (Mg) helps improve tea yield and quality, yet many tea plantations in China commonly exhibit magnesium deficiency. Therefore, studying the mechanisms of Mg²⁺ leaching in tea plantation soils is of significant importance. This study investigates how nitrogen fertilizer application affects the leaching mechanisms of magnesium in soil through pot experiments. The control group (N0) consisted of pots without tea seedlings and no nitrogen fertilizer solution added, only an equivalent amount of ultrapure water was used. The experimental groups were: N1 (no tea seedlings, 0.75 mmol L^− 1 nitrogen), N2 (no tea seedlings, 1.5 mmol L^− 1 nitrogen), N3 (no tea seedlings, 3.0 mmol L^− 1 nitrogen), TN0 (tea seedlings, no nitrogen), TN1 (tea seedlings, 0.75 mmol L^− 1 nitrogen), TN2 (tea seedlings, 1.5 mmol L^− 1 nitrogen), and TN3 (tea seedlings, 3.0 mmol L^− 1 nitrogen). The results show that the correlation between nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), and Mg in the soil with tea seedlings is higher than in soil without tea seedlings. This indicates that tea planting promotes the leaching of Mg²⁺ in the soil. Further investigation revealed that excessive nitrogen application reduces the soil pH, activates aluminum ions (Al³⁺) in the soil, and competes with Mg²⁺ for net adsorption sites, further exacerbating the leaching of Mg²⁺. Additionally, excessive use of nitrogen fertilizer limits the roots’ ability to absorb nutrients, indirectly leading to the leaching of Mg²⁺. We believe that excessive application of nitrogen fertilizer in tea gardens will exacerbate the leaching of Mg²⁺ in the soil.

In purple soil areas of China, there is a traditional practice of breaking up bedrock to obtain soil matrix by hoeing. Purple soil is formed by the development of mud shale with low hardness and high brittleness, which is easy to break under mechanical action. Research on the effect of deep vertical rotary tillage (DVRT) in breaking up the bedrock on soil infiltration performance is still lacking. This study selected a hillslope with 18 cm, 25 cm, and 40 cm soil depths at the upper, middle, and lower slopes, respectively. They investigated differences in soil infiltration capacity after DVRT and rotary tillage (RT) and identified the main controlling factors responsible for differences. The effects of different bedrock fragment contents (RFC, range 0-70%) and the bedrock size (0-5, 5-10, 10-20 mm) on saturated hydraulic conductivity (Ks) were investigated with laboratory tests by constant head method. Results are that (1) stabilized soil infiltration rates for the DVRT treatment increased by 150% and 81% relative to the RT treatment at the upper and middle slope positions, and the lower slope position decreased by 80%. (2) The Kostiakov model shows that the DVRT broken bedrock promotes soil infiltration performance on the upper and middle slopes but inhibits this at lower slope. (3) With increased RFC, saturated hydraulic conductivity decreased and then increased, and RFC thresholds existed to change the inhibition/promotion effect. The thresholds for bedrock fragments with grain sizes of 0-5, 5-10, and 10-20 mm were 74%, 59%, and 53%, respectively. It is suggested that DVRT can regulate the soil infiltration in shallow hillslopes and promote rainwater in-situ utilization.

Purpose

The goal of global carbon (C) neutralization has raised concerns about the potential of soil organic carbon (SOC) storage, particularly regarding the role of soil microbial activities across aggregate classes. Reasonable tillage methods drive microbial community within soil aggregates, so have a stronger ability to utilize carbon sources. However, simultaneously studying the effects of tillage methods through microbial activity, functional and structural diversity at the aggregate level is relatively rare, and seasonal changes in the ability to utilize carbon sources of microbial communities remain largely unknown.

Methods

Initial from 2002, a 14-year long-term tillage experiment started; then in 2016–2017, we tested the following tillage methods: no tillage (NT), rotary tillage (RT), subsoiling (ST) and conventional tillage (CT).

Results

Compared with CT, ST had the most significant promoting effect on microbial activity across aggregate classes, and microbial activity (ATP and SIR) decreased with the aggregate classes decreasing. ATP and SIR increased by 3.23 µmol·g^− 1 and 15.94 µg CO₂·g^− 1·d^− 1 in winter wheat growth, and increased by 2.39 µmol·g^− 1 and 31.16 µg CO₂·g^− 1·d^− 1 in summer maize growth. Microbial communities in aggregates under ST and NT had greater diversity and ability to utilize carbon sources compared with CT, and those function showed the order of 5 − 2 > 2-0.25 > 0.25–0.053 mm. The microbial activity and diversity were higher in summer maize growth.

Conclusions

Therefore, ST is a promising tillage method for enhancing the soil microbial activity and diversity. Our study provides a fundamental understanding for the utilization of carbon sources by microbial community whithin aggregate level and highlights the importance of reasonable tillage methods.

Purpose

Our purpose is to reveal the natural enrichment patterns of metals in the Holocene soils of the Southern Loess Plateau.

Methods

Element and mineral contents and particle size were measured using X-ray fluorescence spectrometry, X-ray diffractometry, and laser diffraction, respectively.

Results

The study area has a subtropical climate with average annual precipitation and temperature of ~ 800 mm and ~ 15.3 °C during the mid-Holocene. At this time the summer monsoon and non-summer monsoon supplied ~ 440 mm and ~ 360 mm of precipitation, respectively. Soil moisture was in a positive balance and persistent gravity water occurred with a moisture content > 20% in the mid-Holocene paleosol.

Conclusions

Natural enrichment of heavy metals occurred in the mid-Holocene paleosol, and the enrichment of heavy metals in the mid-Holocene paleosol do not meet the soil pollution standards and is safe for agricultural production. The mechanism of natural heavy metals enrichment in the mid-Holocene paleosol was as follows: The warm and humid climate enhanced the summer monsoon precipitation, causing a positive soil moisture balance, and persistent gravity water and soil moisture content > 20% caused strong leaching and hydrolysis of minerals, which resulted in enhanced clay formation and heavy metals enrichment.

Production systems can affect soil properties, such as soil fertility and microbiological community and activity, favoring plant growth and crop yield. This study aimed to investigate the effect of successive cropping systems on the chemical, biochemical, and biological properties of a tropical Oxisol and their relationship with cotton initial growth and nutritional status. soil samples were collected in areas with different soybean/maize/cotton cropping system histories (T0—consolidated soybean/corn system; T1—first year of soybean/cotton system; T2—second year of soybean/cotton system; T3—third year of the soybean/cotton system, and T4—fourth year of the soybean/cotton system; T10—tenth year of soybean/cotton system). First, we evaluated the effect of T0—T4 on soil properties and cotton initial growth (cropping history experiment). Then, we evaluated the effect of dilution and autoclaving in T10 samples on soil properties and cotton growth (soil dilution/autoclaving experiment). Both experiments were carried out under greenhouse conditions. in the cropping history experiment, we observed that longer soybean/cotton systems increased P availability and legacy P index in soil and favored arbuscular mycorrhizal colonization in cotton roots and P uptake by cotton plants. Similarly, we observed in the soil dilution/autoclaving experiment that the sterilization limited the mycorrhizal colonization and induced P deficiency, even with available P above the critical limit in soil. the results indicated that the successive soybean/cotton cropping for several years (long-term) stimulates root mycorrhizal colonization of cotton and increases legacy P in soil compared to the recent soybean/cotton cropping, improving legacy P exploration, P uptake, and the growth and development of cotton plants.

The objective of this study was to investigate the influence of composting method on changes in compost structure and to evaluate the effects compost, phosphorous levels and Streptomyces inoculation on soil biochemical properties and the growth of forage maize in a loess soil. The effect of simultaneous application of urea and Streptomyces inoculation in the decomposition of wheat straw and the formation of mature compost was investigated. A 90-day pot experiment was conducted to assess the alterations in soil microbial activity, enzymatic activity, nutrient concentrations in both soil and plants, and the growth characteristics of maize plants The soil was thoroughly mixed with 2% compost (simple (C1) and enriched (C2)) and four levels of phosphorus (0, 10, 40, and 100 mg kg⁻¹); Additionally, two levels of Streptomyces were inoculated on maize seeds. Field emission scanning electron microscopy and Fourier transform infrared spectroscopy revealed compositional and morphological changes during composting. Pot experiment demonstrated enhanced maize growth with enriched compost, Streptomyces inoculation and phosphorus fertilization. These treatments significantly increased plant biomass and nutrient content. Soil biochemical analysis showed increased microbial activity, enzyme levels, and organic carbon content with compost and Streptomyces. Phosphorus application improved soil fertility and enzymatic activity. Simultaneous application of compost, triple superphosphate and inoculation with Streptomyces led to a significant increase in soil-available phosphorus and plant phosphorus content. The findings of this study highlight the importance of combining compost, phosphorus, and Streptomyces for optimal maize growth and enhancing crucial soil microbial and biochemical functions.

The aim of the manuscript was to verify the hypothesis whether the algal biomass of Chlorella vulgaris added as a fertilizer affects the properties of a sandy soil and the leachates from that soil. A pot experiment was conducted using sandy soil, which was enriched with a suspension of live Chlorella vulgaris cells. The concentrations of total nitrogen (N_total), ammonium nitrogen, nitrate nitrogen, total phosphorus (P_total), phosphate phosphorus, potassium, sulphates, turbidity, pH and electrolytic conductivity (EC) were determined in the leachates from soil. Soil samples from each pot were analysed for N_total, P_total, P_available, K_available, calcium (Ca), organic carbon (C_org.) and pH. Soil fertilized with suspended biomass of Chlorella vulgaris was enriched with nutrients, mainly nitrogen, phosphorus and calcium. The use of algae has also helped reduce nutrient losses in the soil. There was an increase in the concentration of SO₄²⁻ ions in the tested leachates, which could pose a potential threat to the environment. Conducted studies confirm the hypothesis that Chlorella vulgaris added to sandy soil as a suspension of living cells affects the fertilizing properties of the soil and the composition of leachates from the fertilized soil. Soil fertilized with Chlorella vulgaris biomass is more resistant to nutrient leaching. An important conclusion of the study is that the composition of soil leachates needs to be monitored when testing and applying this type of fertilizer, due to the risk of sulphates entering into the groundwater.

This study investigates the ecological stoichiometric characteristics and driving factors of carbon (C), nitrogen (N), and phosphorus (P) in deep sediments within the critical zone of South Dongting Lake Wetland. Correlation analysis, partial least squares structural equation modeling (PLS-SEM), and gradient boosted decision tree (GBDT) algorithm were employed for this investigation. The results showed that the mean values of the total carbon (TC), soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP) contents in sediments are 9.0, 7.3, 0.9, and 0.5 g kg^− 1, respectively. Sediment C, N, and P contents tended to decrease with increasing burial depth (H). The mean ratios of C/N, C/P, and N/P in sediments were 10.5, 46.5, and 5.1, respectively, notably lower than the averages in wetland soils across China. Lower C/N and C/P ratios indicate that the decomposition rate of organic matter is relatively fast and organic P is prone to mineralization in sediments. Additionally, the lower N/P ratio implies N limitation within the sediments. The TC, SOC, TN, and TP exhibited significant negative correlations with both H and redox potential (Eh), while showing positive associations with water content (W). Moreover, these factors influence ecological stoichiometric ratios (ESR) by directly affecting C, N, and P contents in sediments. The GBDT modelling revealed that TN primarily influenced C/N ratios, while TP predominantly controlled C/P and N/P ratios. The contents of C, N, and P, as well as their ESR in deep sediments of wetland are mainly controlled by H, Eh, and W.

Climate change has significantly led to the intensification of its associated stresses such as salinity, drought, and extreme temperature in agriculture, threatening global food security and safety. In this review, we performed a bibliometric analysis to provide information on the research trends in abiotic stress. The results show that salinity has been revealed to be the most alarming stress in recent years. Salinity or salt stress, is the primary abiotic stressor that significantly impacts plant development, yield, and productivity, particularly in arid and semi-arid regions worldwide. This stress causes a significant loss of crop productivity by disrupting water and nutrient uptake. Plant symbionts, particularly fungal endophytes play a key role in mitigating salinity stress in crop plants. Endophytic fungi, particularly Piriformospora indica, and several species of dark septate endophyte (DSE) living symbiotically within plant tissues, are revealed as sustainable and promising tools to mitigate the destructive impacts of salinity stress. Their interaction with the host plants induces the production of osmolytes and antioxidative enzymes, modulates plants to manage osmotic stress, and prevents the accumulation of harmful reactive oxygen species (ROS). Despite these advancements, understanding the specific mechanisms of how these fungi enhance salinity tolerance in host plants remains a research gap. This review synthesizes existing literature, identifies research gaps, and proposes future research directions. It provides a comprehensive overview of the role of endophytic fungi in ameliorating salinity stress, optimizing agricultural practices, and developing sustainable solutions in the context of climate change.

Understanding how phosphorus (P) deficiency during the reproductive phase of soybean [Glycine max (L.) Merril] affects nitrogen (N) acquisition via biological N fixation (BNF), and seed yield per unit of the accumulated nutrient remains incomplete. Soybean plants were fertigated with a sufficient concentration of P in the nutrient solution (500 µmol L^-1 P) until flowering. Subsequently, plants were maintained under this condition or subjected to nutrient deficiencies (20 or 100 µmol L^-1 P), resulting in three regimes of P supply during the reproductive phase. At the onset of maximum grain-filling rate and physiological harvest, various parameters were assessed, including nodulation traits, plant nutritional status and biomass production, accumulation, partitioning, and utilization efficiency of P and N. P deficiency after flowering negatively impacted soybean yield and dry mass production, as well as the concentration of P and N in plant organs, their total shoot content, and partitioning to grains. The poor BNF performance was associated with a reduction in the number and dry mass of nodules, triggered by a decrease in plant’s N demand. Nevertheless, low-P stress did not affect seed yield per unit of acquired nutrient, which was related to the fact that the decline in N partitioning to grains was accompanied by a proportional decreasing in their N concentration. The down-regulation of BNF, rather than an impaired N utilization efficiency, contributes to explaining reduced yield of soybean plants facing post-flowering P deficiency. Therefore, the development of precise P fertilization management approaches to maximize BNF and crop yield should prioritize strategies that ensure adequate P supply across the reproductive phase of soybean.