Plant Nutrient Dynamics Research Articles

Dynamics of major plant nutrients and enzymatic activities in soil influenced by application of biochar and organic waste.

The concentration of salt ions influences the availability and plant nutrients dynamics in the soil. Proper management of these ions can enhance food grain production, helping to feed the growing population. In this experiment, nine fertility combinations were followed to enhance the soil organic carbon and reduce the salt toxicity and monitor the plant nutrient availability. An incubation experiment was conducted for the period of one year with different organic soil amendments in combinations including biochar (BC), pressmud (PM), and farm yard manure (FYM) as follow: T1-control, T2-RDF, T3-FYM (10 t/ha), T4-PM (10 t/ha), T5-BC (10 t/ha), T6-FYM (5 t/ha) + PM (5 t/ha), T7-FYM (5 t/ha) + BC (5 t/ha), T8-PM (5 t/ha) + BC (5 t/ha), T9-FYM (5 t/ha) + BC (2.5 t/ha) + PM (2.5 t/ha). Results showed that addition of organic substance (10 t/ha) significantly (p < 0.05) affected soil pH and electric conductivity. Plant nutrient availability (N, K, and S) was also influenced by application of organic substance (10 t/ha). Organic C and available N were recorded the highest in the treatment T7 (FYM-5 t/ha + BC -5 t/ha); whereas, the highest available K and S were observed in treatment T5 (BC-10 t/ha). The microbial soil fertility indicators (alkaline phosphatases, arylsulphatase, dehydrogenase activity and microbial biomass carbon) were measured the highest in FYM (5 t/ha) + BC (5 t/ha) applied treatment. In conclusion, application of organic substance 10 t/ha (biochar alone or with FYM) improved the plant nutrient availability and soil microbial activities in saline soil. It could be a suitable option for enhancing the soil fertility in saline soils.

Zinc fortification and legume incorporation in forage based cropping systems: Implications for yield and nutrient dynamics

Aim: To evaluate the synergistic effects of legume intercropping and zinc fortification on forage yield, and plant and soil nutrient dynamics. Methodology: The experiment was laid out in a Factorial Randomized Block Design. Treatment combinations included five cropping systems, i.e., sole maize, sole cowpea, sole soybean, maize + cowpea (2:1), maize + soybean (2:1) and three zinc levels; Zn0= control or no zinc application, Zn1 = 20 kg ZnSO4 ha-1 (basal soil application) and Zn2 = 20 kg ZnSO4 ha-1 (basal soil application) + 0.5% ZnSO4 sprayed twice (30 DAS and 50 DAS). Results: Sole maize recorded highest dry matter (11938 kg ha-1) yield. Soil + foliar zinc application (Zn2) recorded an increase of 37.93 % increase in dry matter yield over control (Zn0). Maize + legumes recorded higher nitrogen uptake. There was an overall increase (122.34%) in zinc uptake from Zn0 to Zn2. Soil + foliar applied Zn increased ZnUE by 27.60 % (619.14 kg) over soil applied Zn (485.19 kg). Zn application increased Zn values of soil to 0.50 ppm with soil application and 0.56 ppm with soil + foliar application from the initial value of 0.36 ppm. Interpretation: Intercropping of legumes and application of 20 kg ZnSO4 as basal soil application plus two foliar applications of 0.5% ZnSO4 at 30 and 50 days after sowing significantly increased forage yield, nutrient uptake and enhanced soil zinc levels. Key words: Cropping systems, Intercropping, Legumes, Nutrient dynamics, Yield, Zn fortification

Optimizing nitrogen fertilization in maize: the impact of nitrification inhibitors, phosphorus application, and microbial interactions on enhancing nutrient efficiency and crop performance.

Despite the essential role of nitrogen fertilizers in achieving high crop yields, current application practices often exhibit low efficiency. Optimizing nitrogen (N) fertilization in agriculture is, therefore, critical for enhancing crop productivity while ensuring sustainable food production. This study investigates the effects of nitrification inhibitors (Nis) such as Dimethyl Pyrazole Phosphate (DMPP) and Dimethyl Pyrazole Fulvic Acid (DMPFA), plant growth-promoting bacteria inoculation, and phosphorus (P) application on the soil-plant-microbe system in maize. DMPFA is an organic nitrification inhibitor that combines DMP and fulvic acid for the benefits of both compounds as a chelator. A comprehensive rhizobox experiment was conducted, employing varying levels of P, inoculant types, and Nis, to analyze the influence of these factors on various soil properties, maize fitness, and phenotypic traits, including root architecture and exudate profile. Additionally, the experiment examined the effects of treatments on the bacterial and fungal communities within the rhizosphere and maize roots. Our results showed that the use of Nis improved plant nutrition and biomass. For example, the use of DMPFA as a nitrification inhibitor significantly improved phosphorus use efficiency by up to 29%, increased P content to 37%, and raised P concentration in the shoot by 26%, compared to traditional ammonium treatments. The microbial communities inhabiting maize rhizosphere and roots were also highly influenced by the different treatments. Among them, the N treatment was the major driver in shaping bacterial and fungal communities in both plant compartments. Notably, Nis reduced significantly the abundance of bacterial groups involved in the nitrification process. Moreover, we observed that each experimental treatment employed in this investigation could select, promote, or reduce specific groups of beneficial or detrimental soil microorganisms. Overall, our results highlight the intricate interplay between soil amendments, microbial communities, and plant nutrient dynamics, suggesting that Nis, particularly DMPFA, could be pivotal in bolstering agricultural sustainability by optimizing nutrient utilization.

INFLUENCE OF MINERAL NUTRITION ON THE SOIL HEALTH AND PRODUCTIVITY OF COCONUT PALMS (Cocos nucifera L.) IN TROPICAL LAND USE SYSTEMS

Perennial plantation crops, such as coconut trees require the systematic addition of nutrients for sustained growth and productivity. This study aimed to understand plant and soil nutrient dynamics, root health and soil biological properties upon addition of specific nutrients in tropical land use systems. Field experiments in randomised block design were conducted in Agro-Ecological Unit-3 (AEU-3) and Agro-Ecological Unit-9 (AEU-9) from 2014 to 2020. Treatments were T1 (site-specific nutrient management practices (SSNM), T2 (SSNM without sodium chloride); T3 (SSNM without gypsum); T4 (SSNM along with the 50 g microbial formulation Kera Probio); T5 (Farming practice without any amendments or nutrients). Root health parameters, cumulative nut yield and nutrient dynamics in soil and leaf samples were estimated at the beginning and the end of the study. Systematic provision of all the essential nutrients resulted in significant increase content of N (1.39%), P (0.164%), K (1.71%), Ca (0.406%) and Mg (0.175%) in index leaves of coconut trees in sandy soils. Foliar nutrient levels of coconut trees grown in laterite soils were 1.21% N, 0.142% P, 1.27% K, 0.504% Ca and 0.146% Mg. In AEU-3, treatment that received all amendments and nutrients showed highest organic carbon content at the three depths as 6.79 g kg-1soil, 5.39 g kg-1 soil and 3.82 g kg-1, soil, respectively. In AEU-3, 61% increase in yield was observed, while in AEU-9,40% increase was recorded. Application of gypsum resulted in downward displacement of K and Mg indicating that gypsum is required for the amelioration of sub soil acidity in sandy soils. However, the displacement effect was less pronounced in laterite soils and beneficial effect of gypsum was evident with the enhancement of exchangeable Ca. Hence sandy soils require application of inputs as per T3 (T1 without gypsum), with external organic inputs and palm residues whereas in laterite soils application of treatments as per T1 is required with in situ palm residue recycling. Key words: coconut, leaf nutrients, sandy soil, laterite soil, root health, dehydrogenase.

Time since fire affects ecological stoichiometry of plant–soil–microbial systems of Betula platyphylla, a pioneer species in burnt areas of China’s boreal forest

Plant stoichiometry and nutrient allocation may reflect adaptation strategies to environmental nutrient changes. Fire, as a major disturbance in forests, mediates soil nutrient availability that may influence plant nutrient dynamics. However, plant–soil stoichiometric allocation strategies during different post-fire periods and the effects of soil, enzymes, and microbial biomass on plant stoichiometry are largely unknown. The pioneer tree species Betula platyphylla in burnt forests of northern China was the object of this study, and severely burned areas selected with different fire years. Nearby unburned areas acted as a control. Carbon (C), nitrogen (N), and phosphorus (P) contents in leaves, branches, and fine roots and rhizosphere soil, C-, N- and P-acquiring enzyme activities were examined. Microbial biomass C, N, and P were measured, and factors influencing C:N:P stoichiometry of plants during the burned area restoration were explored. Our results show that C and N contents in leaves increased with time since fire, while C and P in branches and C, N and P in fine roots decreased. Activities of C-, N-, and P-acquiring enzymes and microbial biomass N increased with time since fire. Redundancy analysis showed that changes in soil N-acquiring enzyme activity, microbial biomass C, and N had significant effects on plant ecological stoichiometry. These results show a significant flexibility in plant nutrient element allocation strategies and C:N:P stoichiometric characteristics. Soil extracellular enzyme activity drives the changes in stoichiometry during the process of post-fire restoration.

Change in the Ecological Stoichiometry of Carex thunbergii in Response to Seasonal Dynamics and Environmental Factors in Shengjin Lake, China

Exploring the effects of environmental factors and plant physiological processes on plant nutrient stoichiometry is of great significance to understanding how wetland vegetation distributes and maintains function. However, we have a limited understanding of how the combination of plant communities and seasonality with soil physicochemical properties affects nutrient stoichiometry in wetland plants. In this study, we examined these factors in Carex thunbergii and soil across four types of plant communities dominant in the riparian zone of Shengjin Lake during the non−flooding periods of December 2020 and March 2021. In winter, the total foliar C, N, and P concentrations decreased along with an increase in plant coverage, which did not differ in spring. The C, N, C: P, and N: P of foliage significantly increased over the season, while soil C, N, C: P, and N: P significantly decreased over the season. Both in winter and spring, soil C and soil N decreased along with the increase of plant coverage. Our results suggest that both plant community and soil physicochemical properties have a significant influence on plant nutrient stoichiometry. This study improves our understanding of the seasonal dynamics of plant nutrients under different communities and soil physicochemical properties.

Broadleaf trees switch from phosphorus to nitrogen limitation at lower latitudes than conifers

Nitrogen (N) and phosphorus (P) are common limiting elements for terrestrial ecosystem productivity. Understanding N–P nutrient limitations patterns is crucial for comprehending variations in productivity within terrestrial ecosystems. However, the global nutrient limitation patterns of woody plants, that dominate forests, especially across different functional types, remain unclear. Here, we compiled a global dataset of leaf N and P concentrations and resorption efficiency (NRE and PRE) to explore latitudinal nutrient limitation patterns in natural woody plants and their environmental drivers. Based on published fertilization experiments, we compiled another global woody plant nutrient database to validate such identified patterns. The results showed that with increasing latitude, the relative P vs N resorption efficiency (PRE minus NRE) and the N and P ratio decreased in woody plant leaves, suggesting that the nutrient status of woody plants shifts from P to N limitation as latitude increases, with a switching point of N–P balance occurring at mid-latitudes (42.9°–43.6°). Different functional types exhibited similar trends, but with different switching latitudes of N vs P limitation. Due to the lower N uptake capacity of broadleaves than conifers, broadleaves reached N–P balance at lower latitudes (39.6°–43.3°) than conifers (57.1°–59.1°) in both hemispheres. Data from fertilization experiments successfully identified 81 % of the N limitation cases and 91 % of the P limitation cases identified using the first database. N and P limitation cases for conifers and broadleaves were also well identified separately. The latitudinal nutrient limitations in global woody plants are primarily shaped by climate and soil. Our study demonstrates the switching latitudes of N vs P limitation which varies between broadleaves and conifers. These findings enhance our understanding of plant nutrient dynamics in global climate change and aid in refining forest management.

Retraction Note: Plant nutrient dynamics: a growing appreciation for the roles of micronutrients

Retraction Note: Plant nutrient dynamics: a growing appreciation for the roles of micronutrients

Can Plant Nutrient Dynamics and Indian Mustard Yield Be Influenced by Addition of Organic Amendments Under Saline Sodic Soils?

ABSTRACT Arid and semi-arid regions are having huge potential for agricultural production but also have limitations of salinity and alkalinity. By mediating rhizospheric environment with the application of organic and inorganic nutrient sources, Indian mustard yield could be enhanced in these areas. For this, a field experiment was conducted to study the effect of organic (FarmYard Manure and vermicompost) and inorganic (urea) amendments with irrigation water of different sodium absorption ratios (SAR; 6, 10, 20 and 30). The experiment was laid out in a split-plot design (SPD) with 24 treatment combinations keeping different SAR in main plots and organic and inorganic nitrogen sources in sub plots. Experiment results revealed that increasing SAR levels reduced the availability of major plant nutrients, i.e. nitrogen, phosphorus and potassium. The soil organic carbon mineralization rate and Indian mustard seed yield were also deceased with increasing levels of SAR. Application of nitrogen through farm yard manure (FYM) and vermicompost decreased the electrical conductivity (EC), pH, and enhanced the cation exchange capacity (CEC) of soil solution. Application of 50% recommended dose of nitrogen (RDN) through urea and 75% through vermicompost produced maximum seed and stover yield of Indian mustard. Thus, supply of recommended dose of nitrogen as inorganic (50%) and organic (75%) sources improved the soil health and Indian mustard yield of arid lands with sodic irrigation water. The use of organic sources in place of sole application of N fertilizer may be a potential management option in sodic groundwater irrigated areas for enhancing mustard crop yield.

Management of plant nutrient dynamics under alkaline soils through graded application of pressmud and gypsum.

An incubation experiment was conducted to monitor the effect of different organic matter inputs with the graded application of gypsum at different time intervals on soil pH, sodium (Na) content and available plant nutrients like nitrogen (N) and sulphur (S) in alkaline soil. The experiment was formulated with nine treatments, i.e. control (T1), recommended dose of fertilizer (RDF) (T2), RDF+Gyp1 (T3), RDF+FYM5+Gyp2 (T4), RDF+FYM10+Gyp1 (T5), RDF+PM5+Gyp2 (T6), RDF+PM10+Gyp1 (T7), RDF+FYM2.5+PM2.5+Gyp2 (T8), RDF+FYM5+PM5+Gyp1 (T9) with three replications. Periodical soil samples were taken at six and twelve months intervals. Results showed that the addition of organic matter reduced the pH and Na content in the soil. More reduction was observed at one year period as compared to six months. The addition of farmyard manure (FYM) and pressmud (PM) at 10 t/ha with gypsum (1 t/ha) improved available N and available S content as compared to organic inputs (5 t/ha) with gypsum (2 t/ha) in soil. Pressmud application with FYM showed better availability of plant nutrients and a reduction of soil pH (8.39 to 7.79) and Na content from 626 to 391 mEq/L in the soil during the incubation period. During the study, the application of treatment T9 (FYM and PM in equal ratio with 1 t/ha gypsum) showed a better availability of available N (175 to 235 kg/ha) and S (15.44 to 23.24 kg/ha) and reduced the active ion concentration of Na. This study is very useful for the management of sodium toxicity, improving soil health and the mineralization rate of organic matter through the application of organic inputs for sustainable crop production.

Effects of Temperature Variation on Plant Growth in East African Countries

Purpose: The aim of this study was to explore the effects of temperature variation on plant growth in East African countries.&#x0D; Methodology: The study adopted a desktop research methodology. Desk research refers to secondary data or that which can be collected without fieldwork. Desk research is basically involved in collecting data from existing resources hence it is often considered a low cost technique as compared to field research, as the main cost is involved in executive’s time, telephone charges and directories. Thus, the study relied on already published studies, reports and statistics. This secondary data was easily accessed through the online journals and library.&#x0D; Findings: The findings revealed that there exists a contextual and methodological gap relating to the effects of temperature variation on plant growth in east African countries. Preliminary empirical review revealed that temperature variation influences plant nutrient uptake, nutrient assimilation and utilization by plants, impacting their growth and nutritional status. The findings emphasize the need to consider temperature effects on plant nutrient dynamics in agriculture and ecosystem management. The effects of temperature on plant growth were found in most of the studies reviewed.&#x0D; Unique Contribution to Theory, Practice and Policy: The Optimal Temperature Theory, Temperature Stress Theory (Acclimation and Heat Shock Proteins), Photoperiodism and Vernalization Theory may be used to anchor future studies on the Effects of Temperature Variation on Plant Growth in East African Countries. Studying the molecular mechanisms underlying plant responses to temperature variation is essential. Uncovering the genetic and molecular pathways involved in temperature stress responses will enable the development of crops with enhanced temperature tolerance and resilience. Additionally, the development of robust predictive models that integrate climate data, physiological processes, and crop responses is crucial. These models will assist in assessing the potential impacts of future temperature scenarios on plant growth and enable the implementation of adaptive measures in agriculture.

Macro and Micro-Nutrient Accumulation and Partitioning in Soybean Affected by Water and Nitrogen Supply.

This study aimed to investigate the influence of water availability and nitrogen fertilization on plant growth, nutrient dynamics, and variables related to soybean crop yield. Trials were performed in Teresina, Piauí, Brazil, using randomized blocks in a split-split plot arrangement. The plots corresponded to water regimes (full and deficient), the split plots to N fertilization (0 and 1000 kg ha-1 N-urea), and the split-split plots to harvest times of soybean plants (16, 23, 30, 37, 44, 58, 65, 79 and 86 days after emergence), with three replicates. In general, the accumulation and partitioning of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulphur (S), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn) and boron (B) were decreased in plants subjected to water deficit and without N fertilization. Although nitrogen fertilization promoted elevated N accumulation in tissues, it did not result in any significant yield gain, and the highest seed yields were found in plants under full irrigation, regardless of N supplementation. However, deficient irrigation decreased the seed oil content of N-fertilized plants. In conclusion, N fertilization is critical for nutrient homeostasis, and water availability impairs biomass and nutrient accumulation, thereby limiting soybean yield performance.

RETRACTED ARTICLE: Plant nutrient dynamics: a growing appreciation for the roles of micronutrients

RETRACTED ARTICLE: Plant nutrient dynamics: a growing appreciation for the roles of micronutrients

Can Application of Pressmud Mediated Plant Nutrient Dynamics Under Lead Contaminated Soils of Indian Vertisol?

Long- term application of marginal quality water accumulated significant amount of pollutant into the soil. It reduces soil health parameters, and crop yield and their quality. In this regards, graded application of pressmud (PM), i.e. 0, 2.5, 5 and 10g/kg was applied on lead (Pb) contamination level (0, 100, 150, 300mg/kg) and evaluated interaction effect on plant nutrients uptake by spinach. Analytical data showed that increasing the PM levels enhanced the macro (phosphorus, potassium, sulphur) and micro-nutrient (zinc, copper, manganese, iron) concentration into the soil. Whereas, increasing the level of Pb significantly (p ≤ 0.05) reduced the P, K and S nutrient concentration and uptake pattern by spinach crop. Increasing PM levels (control to 10g/kg soil) improved P, K and S by 46.99, 98.96 and 76.79%, respectively in soil. This study is useful to formulate management strategies for minimizing Pb contamination in the food chain by the application of PM mostly in peri-urban areas.

Effects of hydrological regime on Taxodium ascendens plant decomposition and nutrient dynamics in the Three Gorges Reservoir riparian zone

Riparian plants are an integral part of the river ecosystem and have significant impacts on the water quality of the reservoir area. The special hydrological process of the riparian zone makes it possible to become a “source” or “sink” of organic matter and nutrients. This study quantifies the flooding period on the decomposition as well as nutrient dynamics of leaves from artificially regenerated Taxodium ascendens in the riparian zone of the Three Gorges Reservoir (TGR) in China. Five decomposition treatment groups were exposed to 10, 30, 60, 90, and 180 days of decomposition: conventional water (T1), mild drought stress (T2), saturated water content (T3), light flooding stress (T4), and severe flooding stress (T5). In T4 and T5, the decomposition rate of T. ascendens leaves was significantly higher than that of T1, T2, and T3. All the leaf C, N, P, and K concentrations at the end of the test were lower than their respective starting values. The concentrations of N and P in the overlying water decrease to various degrees due to decomposition. At the end of the study, the TN content was 1.34 times (T4) and 1.16 times (T5) higher than that of the control group, and the TP content was 3.97 times (T4) and 3.21 times (T5) higher than that of the control group. Leaf decomposition increases the content of N and P in the overlying water under flood conditions, which adversely affects the water environment. This study establishes a theoretical framework for understanding how hydrological processes affect leaf decomposition and nutrient release in riparian areas, providing a scientific basis for riparian zone management in TGR.

Soil and Plant Nutrient Dynamics in Castor-based Cropping Systems as Influenced by Conservation Agricultural Practices

A field experiment was conducted during kharif 2021, at Narkhoda farm, ICAR-Indian Institute of Oilseeds Research, to study the effect of conservation agricultural practices on soil and plant nutrient dynamics. The experiment was laid out in split-plot design with 3 replications on red sandy loam soil (Alfisols) under rainfed conditions. The treatments comprised of three tillage treatments in main plots viz., conventional tillage, reduced tillage, zero tillage and four cropping systems with residue incorporation in subplots viz., sole castor, castor + redgram (1:1), castor + greengram (1:3) and castor + groundnut (1:3). The results indicated that at harvest, highest soil organic carbon (SOC) content was found in reduced tillage (0.64%) followed by zero tillage (0.63%) and the lowest in conventional tillage (0.56%). Among inter cropping systems, SOC was recorded highest (0.67%) in castor + redgram (1:1) and lowest (0.55%) in sole castor treatment. The status of post-harvest soil available N, P, K (kg/ha) was recorded highest in reduced tillage (208.6, 54.03, 515.9 kg N, P, K /ha respectively) and lowest in conventional tillage (196.7, 38.57, 486.8 kg N, P, K /ha) while, zero tillage (203.6, 47.15, 506.7 kg N, P, K /ha) was at par with the reduced tillage. Among the cropping systems, castor + redgram (208.1, 60.12, 517.9 kg N, P, K /ha) recorded highest available N, P, K while lowest in sole castor (201.6, 38.60, 494.0 kg N, P, K /ha) treatment. Total N, P, K uptake (kg/ha) by castor crop at harvest was highest in conventional tillage (56.13, 19.99, 31.97 kg N, P, K /ha respectively) followed by reduced (49.24, 16.81, 26.28 kg N, P, K /ha) and the lowest (38.36, 13.15, 21.99 kg N, P, K /ha) was recorded in zero tillage. Among intercropping cropping systems N, P, K uptake by castor crop was recorded highest in sole castor (60.22, 18.66, 32.35 kg N, P, K /ha) treatment while lowest was recorded in castor + redgram (1:1) (26.65, 10.28, 15.93 kg N, P, K /ha). In general, the interaction effect between tillage and intercropping system were found non-significant.

Long-term nitrogen addition alters peatland plant community structure and nutrient resorption efficiency

As an elemental carbon (C) and nitrogen (N) pool in the world, peatlands are very sensitive to environmental changes. Under global warming, the increase in available N affects the dynamic changes of plant community structure and nutrients in a permafrost peatland. This study was based on a long-term in situ N addition experiment that had been conducted for 9 years. It utilized the peatland in the permafrost area of Great Hing'an Mountain as the research object to analyze the effects of N addition on the growth characteristics, community structure, and nutrient dynamics of peatland plants. The N inputs were N1: 6 g N m−2·year−1, N2: 12 g N m−2·year−1 and N3: 24 g N m−2·year−1, respectively. Our results showed that the adding N can affect the plant community structure of peatland by affecting the plant growth characteristics. The diversity and richness of plant species in the peatland decreased as the concentration of added N increased. The long-term N addition can reduce the N limitation of plants to some extent. Still, it could further aggravate their phosphorus (P) limitation, resulting in the joint limitation of N and P or the complete limitation by P. The N resorption efficiency decreased with the increase of N addition level. The P resorption efficiency of different plants had varied responses to the changes in the N nutrient environment. Our study clarified the impact of long-term N addition on the plant community structure and nutrient dynamics of peatland in a permafrost area and provided an important theoretical basis to accurately evaluate the carbon and nitrogen balance of peatland in a permafrost area owing to future climate change.

The 2/3 scaling of twig nitrogen to phosphorus in woody plants

Nitrogen (N) and phosphorus (P) are important elements for plant metabolism and growth. Therefore, the quantification of the scaling relationship of N to P in plant organs can help us understand many fundamental ecological processes. The general scaling relationships between N and P in leaves and in fine roots have been reported. As compared to leaves and fine roots, however, little information is available on the N versus P scaling relationship in the stems of woody plants, especially for twigs. In this study, a comprehensive dataset comprising 2,038 ​N=P paired observations for a total of 536 woody species was compiled and analyzed to determine whether a general scaling relationship exists. The global mean values of twig N and P concentrations and N:P ratios were 9.33 ​mg·g −1 , 1.12 ​mg·g −1 and 10.16, respectively. Twig N and P concentrations and N:P ratios differed significantly within and across functional groups and biomes. Across all of the species, a uniform 0.67 scaling exponent of twig N to P was observed across different functional groups and biomes, i.e., a 2/3-power scaling relationship was observed. However, this numerical value differed across different sites, albeit converging onto 0.67 with increasing sample sizes. Soil total phosphorus was the largest contributor to the variation in the numerical value of the scaling exponent. These results provide useful parameters for stoichiometric growth models, and advance our understanding of the mechanisms underlying plant nutrient dynamics. This study has potential implications in predicting responses of nutrient cycling in terrestrial ecosystem responses to changes in the environment.

Rangeland application of biochar and rotational grazing interact to influence soil and plant nutrient dynamics

Few studies have been conducted to evaluate the use of wood biochar in temperate rangeland ecosystems and none have investigated the interactive influence of wood biochar and cattle trampling activity (associated with short-term rotational grazing) on soils and plants. We conducted a field study on a semi-natural pasture in western Montana, USA to evaluate how wood biochar, with or without short-term intensive trampling affected biochar incorporation depth, soil physicochemical properties, nutrient dynamics, and grass nutrient concentrations with a particular focus on nitrogen (N) and phosphorus (P). We hypothesized that cattle trampling alone would induce soil compaction and generally reduce soil nutrient cycling rates and/or availability, but the presence of biochar prior to trampling could improve soil aeration and grass nutrition. After three months, we found that trampling alone significantly increased surface soil bulk density and reduced the values of nearly all soil N metrics examined in this study; however, the application of biochar prior to trampling improved infiltration rate and increased net nitrification. Trampling also facilitated biochar incorporation into soils. Biochar additions significantly increased soil available organic P (i.e., enzyme extractable P) while reducing soil inorganic P (i.e., CaCl2-P, citrate-P) with or without trampling. Soil P responses appeared to be associated with biochar ortho-P sorption capacity and was more pronounced in soils that had undergone cattle trampling. Changes in soil P were reflected in grass P concentration after three months. Overall, our field study demonstrated that the use of biochar on rangeland soils with short-term rotational grazing could result in a neutral to positive effect on soil and plant nutrients.

Sustainable Community Forest Management in Mexico: An Integrated Model of Three Socio-ecological Frameworks.

The sustainability of management practices in forest ecosystems should provide ecosystem services and maintain the livelihoods that largely depend on the benefits directly derived from forests; but this goal requires various theoretical and analytical approaches. This research aims to develop a conceptual model for sustainable forest management based on the integration of three conceptual frameworks founded on the society-ecosystem interaction: socio-ecological systems, sustainable forest management, and ecosystem services. The results offer a methodological, analytical, organizational, and operational route to integrate a scientific model at the material, causal, and dynamic levels, considering theoretical and empirical information; it uses grounded theory methodology to select the interactions between variables and socio-ecological dynamics of forest ecosystems under community management. For example, it integrates social components (local knowledge, governance, and social organization) and ecological components (diversity and composition of plant species, carbon pools, and nutrient dynamics) to understand their interactions through management practices and the magnitude of the ecosystem services provided according to the local contexts. We illustrate this process by analyzing the influence of governance, decision-making, resource use, and management practices on forest management and ecosystem services; this exemplifies the factors, interactions, and effects on socio-ecological systems based on experience in forest communities. These integrated frameworks provide steps through which our understanding of specific socio-ecological approaches produces better outcomes for sustainable forest management, preserves ecosystems services and benefits livelihoods in Mexican temperate forests.