Availability Of Macronutrients Research Articles

Effects of microbial bio-fertilizers on soil physicochemical properties under different soil water regimes in greenhouse grown eggplant (Solanum Melongena L.)

ABSTRACT The aims of this research were to investigate the effects of microbial bio-fertilizer (BF) application on physicochemical properties of sandy-clay-loam (SCL) soil under three different soil moisture regimes in greenhouse-grown eggplant (Solanum melongena L.). Correlations between the physicochemical soil properties in a greenhouse condition were determined. The microbial bio-fertilizers included Azotobacter chroococum and Azotobacter vinelandii. Experiments were conducted in randomized plots design with three replications. Three different irrigation levels (100% (I100), 60% (I60) and 40% (I40) of field capacity-FC) were applied. Post-harvest soil samples were analyzed for soil physical and chemical characteristics. Bio-fertilizers had positive impacts on physicochemical soil properties. Bio-fertilizers accelerated mineralization of organic residues, thus improved the availability of macronutrients (N, P, K, Ca, and Mg) and micronutrients (Fe, Mn, Zn, and B). The highest total N value (0.143%) was observed in I100 treatment of bio-fertilizer (BF+I100) and the lowest total N (0.087%) was observed in I40 treatment without bio-fertilizer. Bio-fertilizers improved aggregate stability, total porosity, moisture-retention capacity and infiltration rate, and decreased bulk density of the soils. Bio-fertilizers increased water uptake and decreased drought susceptibility of the plants. It was concluded that bio-fertilizers could reliably be used to improve soil physical and chemical characteristics under different irrigation levels.

Evaluation of Vermicompost and Zeolite Ability to Improve Water and Nutrients Retention in A Sandy Soil تقییم قدرة الفیرمیکومبوست والزیولیت على تحسین الاحتفاظ بالمیاه والمغذیات فى أرض رملیة

Improving water retention and nutrients in sandy soils is crucial for agricultural productivity under water shortage. Vermicompost (V) and Zeolite (Z) were applied to soil as alone or mixture to quantify their effect on sandy soil properties, physiological efficiency of nutrientsand water use efficiency of cultivated wheat under three levels of moisture content (100, 80 and 60% from filed capacity) for 60 days in pot experiment. Treatments of vermicompost and zeolite were control-,1 and 2% as alone and 0.5%V+0.5%Z ,0.5%V+1%Z, 1%V+0.5%Z and1%Z+1%V as combined. The mixture of 1% Z+0.5% V had higher fresh and dry weights of wheat, macro nutrients content and uptake by wheat under all levels of moisture content as compared to other treatments. The WUE and Physiological efficiency of NP and K increased significantly by increasing the rates of zeolite and vermicompost either alone or mixture, especially at the lowest moisture content of field capacity. Soil porosity, bulk density, and the availability of soil macronutrients and water were associated by applications of zeolite and vermicompost. So, the synergistic effect of zeolite and vermicompost that carried out during the period of experiment on soil properties and nutrients uptake clearly occurred. Hencethese results are enhancing plant growth under water shortage which can be used to improve, cultivate new areas and to enhance water use efficiency of wheat plant.

The Effect of Macronutrient Availability on Pomegranate Reproductive Development

Pomegranate cultivation has expanded significantly in the last two decades. However, there is limited information on its fertilization requirements and the effect of macronutrient availability on its reproductive development. Two commercial pomegranate cultivars—“Wonderful” and “Emek”—were grown in 500-L containers for 3 years, using a fertigation system. Development and reproduction indices were measured to explore the trees’ responses to elevated levels of nitrogen (N), phosphorus (P) and potassium (K) in the irrigation solution. Andromonoecy rate was affected by nutrient levels only in the first year of the experiment, with higher levels of N and P leading to a greater proportion of hermaphrodites out of total flowers. P level had a positive effect on the total number of hermaphrodites per tree in both varieties. Differences recorded between hermaphroditic and staminate flowers included nutrient concentrations and dry weight. Fruit set and aril number were positively affected by N concentration in the irrigation solution. We conclude that only a severe deficiency of N and P affects the andromonoecy trait, and that at the levels examined in this study, K hardly influences pomegranate reproduction.

Nutrient Timing: A Garage Door of Opportunity?

Nutrient timing involves manipulation of nutrient consumption at specific times in and around exercise bouts in an effort to improve performance, recovery, and adaptation. Its historical perspective centered on ingestion during exercise and grew to include pre- and post-training periods. As research continued, translational focus remained primarily on the impact and outcomes related to nutrient consumption during one specific time period to the exclusion of all others. Additionally, there seemed to be increasing emphasis on outcomes related to hypertrophy and strength at the expense of other potentially more impactful performance measures. As consumption of nutrients does not occur at only one time point in the day, the effect and impact of energy and macronutrient availability becomes an important consideration in determining timing of additional nutrients in and around training and competition. This further complicates the confining of the definition of “nutrient timing” to one very specific moment in time at the exclusion of all other time points. As such, this review suggests a new perspective built on evidence of the interconnectedness of nutrient impact and provides a pragmatic approach to help frame nutrient timing more inclusively. Using this approach, it is argued that the concept of nutrient timing is constrained by reliance on interpretation of an “anabolic window” and may be better viewed as a “garage door of opportunity” to positively impact performance, recovery, and athlete availability.

A meta-analysis on environmental drivers of marine phytoplankton C : N : P

Abstract. The elemental stoichiometry of marine phytoplankton plays a critical role in global biogeochemical cycles through its impact on nutrient cycling, secondary production, and carbon export. Although extensive laboratory experiments have been carried out over the years to assess the influence of different environmental drivers on the elemental composition of phytoplankton, a comprehensive quantitative assessment of the processes is still lacking. Here, we synthesized the responses of P:C and N:C ratios of marine phytoplankton to five major drivers (inorganic phosphorus, inorganic nitrogen, inorganic iron, irradiance, and temperature) by a meta-analysis of experimental data across 366 experiments from 104 journal articles. Our results show that the response of these ratios to changes in macronutrients is consistent across all the studies, where the increase in nutrient availability is positively related to changes in P:C and N:C ratios. We found that eukaryotic phytoplankton are more sensitive to the changes in macronutrients compared to prokaryotes, possibly due to their larger cell size and their abilities to regulate their gene expression patterns quickly. The effect of irradiance was significant and constant across all studies, where an increase in irradiance decreased both P:C and N:C. The P:C ratio decreased significantly with warming, but the response to temperature changes was mixed depending on the culture growth mode and the growth phase at the time of harvest. Along with other oceanographic conditions of the subtropical gyres (e.g., low macronutrient availability), the elevated temperature may explain why P:C is consistently low in subtropical oceans. Iron addition did not systematically change either P:C or N:C. Overall, our findings highlight the high stoichiometric plasticity of eukaryotes and the importance of macronutrients in determining P:C and N:C ratios, which both provide us insights on how to understand and model plankton diversity and productivity.

Control of ecological outcomes through deliberate parameter changes in a model of the gut microbiome.

The generalized Lotka-Volterra (gLV) equations are a mathematical proxy for ecological dynamics. We focus on a gLV model of the gut microbiome, in which the evolution of the gut microbial state is determined in part by pairwise interspecies interaction parameters that encode environmentally mediated resource competition between microbes. We develop an in silico method that controls the steady-state outcome of the system by adjusting these interaction parameters. This approach is confined to a bistable region of the gLV model. In this method, a dimensionality reduction technique called steady-state reduction (SSR) is first used to generate a two-dimensional (2D) gLV model that approximates the high-dimensional dynamics on the 2D subspace spanned by the two steady states. Then a bifurcation analysis of the 2D model analytically determines parameter modifications that drive an initial condition to a target steady state. This parameter modification of the reduced 2D model guides parameter modifications of the original high-dimensional model, resulting in a change of steady-state outcome in the high-dimensional model. This control method, called SSR-guided parameter change (SPARC), bypasses the computational challenge of directly determining parameter modifications in the original high-dimensional system. SPARC could guide the development of indirect bacteriotherapies, which seek to change microbial compositions by deliberately modifying gut environmental variables such as gut acidity or macronutrient availability.

Interactive effects between vegetation structure and soil fertility on tropical ground-dwelling arthropod assemblages

The development of forests undergoing restoration determines the structure of the vegetation, influencing ground-dwelling arthropod composition. Soil fertility can interact with vegetation structure, influencing the diversity and composition of arthropod assemblages through bottom-up effects on developing forests. We evaluated if soil fertility (here defined by the attributes directly related to macronutrient availability) and the vegetation structure in three adjacent areas from different land-use/cover categories (abandoned pasture, riparian forest undergoing restoration, and remnant riparian forest) influences ground-dwelling arthropod assemblages. These areas were subject to a gradient of soil fertility due to the presence of a corral that resulted in a local increase of soil nutrients in the three areas, enabling to evaluate the interaction between soil fertility and vegetation structure. We hypothesized that ground-dwelling arthropod assemblages have lower diversity in pasture, intermediate in forest undergoing restoration and higher diversity in the remnant forest. Furthermore, we expected that increasing soil fertility would have a positive effect in these assemblages through bottom-up effects. Environmental conditions were characterized by vegetation structure and soil chemical attributes variables, whereas arthropods were sampled with pitfalls and identified to morphospecies. Diversity indicators responded differentially to the studied effects. Abundances decreased with soil fertility, and were higher in the forest undergoing restoration, followed by pasture and remnant forest. Species richness also varied among categories, following the same pattern as abundances. On the other hand, diversity indices indicated an interaction between soil fertility and land use category, with larger effects of soil fertility on diversity in the more simplified habitats (pasture and forest undergoing restoration), whereas no bottom-up effects were recorded in the remnant forest; species evenness increased with soil fertility in all studied areas. A redundancy analysis (RDA) indicated that both vegetation structure and soil attributes significantly influenced arthropod composition. Arthropod assemblages in areas undergoing restoration with higher soil fertility and low grass cover were more similar to assemblages in remnant forest when compared to areas with low soil fertility, independently of the vegetation structure, indicating an interaction between these two effects. Therefore, ground-dwelling arthropod assemblages responded both to increasing vegetation complexity resulting from the different land use/cover categories, and to increasing soil fertility, so that they are effective indicators to evaluate the recovery of ecosystems in forest restoration projects and to determine the importance of soil fertility in this process.

Long-term Effect of Integrated Nutrient Management on Soil Nutrient Status, Content and Uptake by Finger Millet Crop in a Typic Kandiustalf of Eastern Dry Zone of Karnataka

ABSTRACTMacronutrients support the most essential functions of the plant. Impact of integrated use of organic and inorganic fertilizers on the macronutrient status in soil and plant were studied in an ongoing 40-year old long-term fertilizer experiment (LTFE) under finger millet mono-cropping system at All India Co-ordinated Research Project for Dry land Agriculture (AICRPDA), Gandhi Krishi Vignana Kendra, University of Agricultural Sciences, Bengaluru, during kharif 2018. The experimental plot in the field was laid out following a randomized complete block design (RCBD) with eight treatments and three replications. Results indicated that continuous application of 100% NPK with Farm Yard Manure (FYM) increased the macronutrient availability in soil N (345.35 kg ha−1), P2O5 (66.58 kg ha−1), K2O (136 kg ha−1), nutrient content and uptake by finger millet grain, straw, roots, and stubbles. Application of FYM @ 10 t ha−1 + 100% RDF over a period of 40 years significantly increased the macronutrient content in soil and uptake by finger millet grain, straw, roots, and stubbles against 100% NPK treatment and control.

PEMBERIAN ABU SEKAM PADI DAN FOSFAT ALAM PADA MEDIUM ULTISOL UNTUK MENINGKATKAN PERTUMBUHAN DAN HASIL PADI GOGO (Oryza sativa L.)

ABSTRACT Rice as a staple food for most of Indonesia's population,their needs increase with increasing population, conversely production decreases. One effort to meet the needs of rice is by planting upland rice in dry land. Ultisol is the most extensive dry land in Indonesia. The yield of upland rice in Ultisol is very low, this is caused by various problems including acid reaction, high Al saturation and P fixation, availability of macro nutrients (N, P, K, Ca, Mg), low micro nutrients (Mo). Rice husk ash and natural phosphate can be used to increase pH and nutrient availability. The purpose of study was to study the effect of the interaction of rice husk ash and natural phosphate in increasing the growth and yield of upland rice ( Oryza sativa L.) on Ultisol medium. The study was conducted at the Faculty of Agriculture greenhouse, University of Riau from March to July 2019. The research was an experiment in the form of a 4x3 factorial using a completely randomized design. The first factor consists of four levels of rice husk ash (0.0; 1.5; 3.0; and 4.5 tons ha -1 ), the second factor of natural phosphate consists of 3 levels (0, 25 and 40 kg P 2 O 5 ha -1 ), each repeated three times. The results showed the interaction between rice husk ash with a dose of 1.5 tons ha -1 and natural phosphate with a dose of 25 kg P 2 O 5 ha -1 increased plant height, number of productive tillers, panicle length, number of paddy grains with pan, paddy grains and dry grain weight milled compared without rice husk ash and natural phosphate, each of these parameters tends to increase higher at the highest dose (4.5 tons ha -1 rice husk ash and 40 kg P 2 O 5 ha -1 natural phosphate).

Evaluate the Effect of Green Fertilizer and Two Sources of Potassium on Growth , Yield , some Chemical Constituents of Roselle Plants (Cv. Sabaheia 17) and the Availability of Macronutrients in Soil after Harvest

Evaluate the Effect of Green Fertilizer and Two Sources of Potassium on Growth , Yield , some Chemical Constituents of Roselle Plants (Cv. Sabaheia 17) and the Availability of Macronutrients in Soil after Harvest

In Vitro Digestion for Control and Monitoring of Food Effects in Relation to Micellarization Index of Carotenoids.

The multifactorial system that influences the availability of macronutrients, micronutrients, and phytoconstituents with relevant bioactivities has been assessed by in vitro digestion protocols, which have become an effective technique to support the health-through-food strategy. The measurement of the significance of food structure, food matrix, synergies and competitive effects, processing features, and even some physiological issues has created valuable scientific and technological information, and the development of harmonized protocols. Now it is possible to make further advances by applying this knowledge to obtain data regarding the potential availability of target compound(s) in the food source within a standard meal context. This protocol describes the measurement of the micellarization index of carotenoids from dietary rich sources with test meals accounting the effects of high vs. low fat and normo-, hypo-, and hypercaloric content.

Soybean macronutrient availability and yield as affected by tillage system

The effect of tillage system (NT-no tillage; CT-conventional tillage; MT-minimum tillage; and NT/scarification, every three years) on soybean nutrient availability and yield was evaluated on Oxisol after 12 years of cultivation. Soil samples were collected at depths of 0.00-0.05, 0.05-0.10, and 0.10-0.20 m and were analyzed for P, K, Ca, Mg, carbon (C), organic matter (OM), pH value, potential CEC, base saturation (BS%), and number of semiquinone organic radicals. The macronutrient concentration in the leaves and amount accumulated in the plants at the blooming stage were determined, as well as the yield of the two soybean crops. The soil pH value, BS% and K, Ca, and Mg concentrations were not influenced by the tillage system. The soil P and OM in the surface layer, however, were inversely proportional to the intensity of soil preparation. The P content in the soil surface layer under NT was twice as high as that of soil under CT. The P content in the soybean leaves under NT was also higher compared to that in the plants under CT and MT. The number of semiquinone radicals was low in the soil surface layer under NT, indicating a small degree of humification. However, soybean yield was not affected by the tillage system.

Sedimentation of ballasted cells-free EPS in meromictic Fayetteville Green Lake.

Fayetteville Green Lake (FGL) is a recognized, extensively studied present-day model of the stratified Proterozoic ocean. Nonetheless, biomass sedimentation in FGL remains hard to explain: while virtually all sediment pigments belong to photosynthetic sulfur bacteria from a chemocline, the isotopic carbon signature of the bulk organic matter suggests its epilimnetic phytoplankton origin. To explain the epilimnetic origin of sedimented carbon, we studied the dominant Synechococci, isolated from FGL. Here, we present experimental evidence that FGL Synechococci produce copious extracellular polysaccharides (EPS) especially when availability of inorganic carbon (Ci ) is high relative to availability of other macronutrients, for example phosphorus. The accumulating EPS become impregnated with calcium, magnesium, and sodium cations and are released to the environment as ballasted cell coverings. Sedimentation of these cell-free EPS can constitute the bulk of pigment-free organic material in FGL sediment. Because increased availability of Ci specifically stimulates production of EPS and the accumulated EPS adsorb cations and become ballasted, we propose the universal role of cyanobacterial EPS in biomass sedimentation in the high-Ci Paleoproterozoic ocean as well as in modern aquatic systems like FGL.

Macronutrient deficiency and anatomic modifications in crambe leaves

This study had the objective of assessing growth, deficiency symptoms and leaf anatomy of crambe plants submitted to macronutrient availability. The experimental design was the complete randomized with four replications. The first treatment consisted of cultivating crambe plants in a nutrient solution completed with N, P, K, Ca, Mg, and S. Using the diagnosis by subtraction, the other treatments consisted of the same solution with individual omission of each nutrient, totaling seven treatments. Supplement of different solutions took place two weeks after emergence. One week forward, visual symptoms of deficiency started to be evaluated. By the end of the experiment, the number of leaves, number of branches, shoot dry matter and leaf anatomic parameters were evaluated. Nutrient deficiency limited shoot dry matter in the following order: N > Ca > P>Mg > S > K. Subtracting Ca from the solution was most limiting to crambe growth once plants did not even reach reproductive stages. Individual subtractions of each macronutrient anatomically altered crambe leaves, especially omitting Ca, K, and S, which reduced tissue thickness.

Anaerobic Conversion of Biodegradable Municipal Solid Waste to Biogas: A Review

Huge quantity of Municipal Solid Waste (MSW) is generated daily. This waste comprises a biodegradable portion which can be converted into biogas (bioenergy) by anaerobic digestion (AD). This study reviews MSW and its management, AD feedstock and their characteristics, factors affecting biogas production in a biodigester and anaerobic co-digestion of Organic Fraction of MSW (OFMSW) with other substrates. Municipal solid waste is managed through waste diversion (reduction, reuse, recycling and recovery) and waste disposal (controlled incineration, landfilling and controlled dumping). AD feedstock includes agricultural waste/residues, animal wastes, energy crops, food waste, forestry crops and residues, organic industrial waste and wastewater, weeds, aquatic algae, sewage and OFMSW. The essential factors that influence the production of biogas are temperature, pH, mixing rate, carbon/nitrogen ratio, organic loading rate, micro and macro-nutrient availability, retention time, nature of the feedstock and digester type. Anaerobic co-digestion of OFMSW with other substrates results in improved AD process stability, enhanced biogas productivity, maximization of the capacity of available feedstock for anaerobic digestion. It is also a cost-effective and improved technique to optimize anaerobic digestion process via the increase in nutrients and bacterial variety in substrates. The generation rate and composition of MSW, as well as the characteristics of OFMSW feedstock for anaerobic digestion, are required for the design of a full-scale biodigester for municipal use. The information provided in this review is invaluable to researchers, governments, industries and other stakeholders interested in anaerobic conversion of biodegradable solids to bioenergy.

PGPR-induced defense responses in the soybean plant against charcoal rot disease

This study aimed to assess the role of two Plant growth promoting rhizobacteria (PGPR), Pseudomonas stutzeri (KX574858) and Pseudomonas putida (KX574857) against charcoal rot instigated by Macrophomina phaseolina in soybean (Glycine max L.) varieties; Ajmeri and NARC grown in pots under greenhouse condition. Macrophomina inocula were added to the soil at the time of sowing. Disease incidence and severity were recorded on 90th day of sowing. Seeds were inoculated with PGPR prior to sowing. Growth parameters such as germination index, shoot height and shoot fresh weight were measured at flowering stage. P. stutzeri significantly (p < 0.05) increased germination index (147% and 115%), shoot height (117% and 103%) and shoot fresh weight (120% and 100%) in cv. Ajmeri and cv. NARC, respectively, in infected plants. Both P. stutzeri (76% and 60%) and P. putida (23% and 22%) significantly decreased the disease severity index of charcoal rot in cv. Ajmeri and cv. NARC, respectively. P. stutzeri induced polyphenol oxidase (435% and 386%), phenylalanine ammonia-lyase (257% and 180%), superoxide dismutase (290% and 240%), peroxidase (733% and 666%) and catalase activities (1867% and 1424%) were linearly increased in cv. Ajmeri and cv. NARC, respectively, after 90 days of infection. Significantly higher accumulation of leaf proline and soluble proteins was recorded in both varieties due to P. stutzeri under infected condition. PGPR enhanced the availability of macronutrients in the rhizosphere of infested soil. The antioxidant and defense enzymes in plant were significantly correlated with disease suppression. The PGPR can be used as a supplement with fungicides to combat adverse effect of disease.

The ‘omnivorous badger dilemma’: towards an integration of nutrition with the dietary niche in wild mammals

Abstract Laboratory studies have demonstrated that, given plenty of food, many animals can achieve a species‐specific macronutrient intake target by selecting nutritionally balanced foods or combining complementary foods. Wild‐living, broad‐scope omnivorous species often face great heterogeneity in the composition of available resources. Hence they may be precluded, either locally or seasonally, from meeting their nutritional preferences. With the aim of shedding light on the nutritional niche breadth of a wild‐living omnivore, the European badger Meles meles, we reviewed available scat‐based studies on badger diet and applied right‐angled mixture triangles to examine the relationships between macronutrient availability and composition of diets. Moreover, to assess the potential of scat analysis to investigate nutritional balancing, we analysed badger diet in two habitats of NW Italy, focusing on identifying the total weight of each food item ‘as ingested’ as accurately as possible. The average macronutrient content of the European badger's diet comprised 40–45% protein‐energy, 30–35% lipid‐energy, and 20–25% carbohydrate‐energy. Macronutrient intake was not constant throughout the year, suggesting that, in some seasons, badgers may be unable to reach their macronutrient target, and that diet balancing is achieved over longer periods. The macronutrient selection strategy of badgers suggests that their feeding habits are close to those of obligate carnivorous mammals, although badgers were found to be more tolerant towards carbohydrates than obligate carnivores. Macronutrient ratios as assessed by scat analysis matched well with those obtained by reviewing available data, confirming that meta‐analyses of diet studies can provide useful information on the macronutrient requirements of elusive wild mammals.

Physico-Chemical Behavior of Natural Minerals along with Synthetic Soil Conditioners on Nutritional Status and Yield Productivity

A field experiment was carried out for two successive seasons (summer season 2017 and winter season 2017/2018) on sandy soil at Ismailia Agric. Res. Station, Ismailia Governorate, Egypt (Latitude, 30˚35' 41.901 N and longitude, 32˚16' 45.834 E) cultivated with sesame and wheat crops respectively, to highlight the effect of applying natural minerals and synthetic soil conditioners alone or in combined on some sandy soil properties and productivity of sesame and wheat crops. Three natural clay minerals (bentonite, vermiculite and zeolite) were added at the rate of 2 ton fed-1. Alone or in combination with three synthetic soil conditioners; hydrogel (HG), polyvinyl alcohol (PVA) and anionic polyacrylamide (PAM) which were added at the rate of 6 Kg fed-1. Results indicated that application of natural minerals and synthetic soil conditioners alone or in combination increased significantly values of soil moisture characteristics (field capacity (FC), wilting point (WP), available water( AW), total porosity(TP)), soil nutrients availability (N, P and K), yield components and total content of macronutrients (N, P and K) in straw, seeds and grains of sesame and wheat. Bentonite being superior as compared to other clay minerals for increasing (FC), (WP), (AW),(TP), EC values , soil nutrients availability (N, P and K), yield components and total content of macronutrients (N, P and K) in straw, seeds and grains of sesame and wheat followed by vermiculite and zeolite while values of soil reaction decreased slightly as compared to control. As for the effect of synthetic soil conditioners, application of synthetic soil conditioners significantly increased total porosity (TP), field capacity (FC), wilting point (WP), available water (AW), EC values, soil nutrients availability (N, P and K), yield components and total content of macronutrients (N, P and K) in straw, seeds and grains of sesame and wheat while pH values decreased as compared to control especially in presence of hydrogel combined with bentonite. Bentonite combined with hydrogel recorded the highest values of soil moisture characteristics (FC, WP and AW), TP, EC values, soil nutrients availability (N, P and K), yield components and total content of macronutrients (N, P and K) in straw, seeds and grains of sesame and wheat. While the inferior treatment values were zeolite combined with polyvinyl alcohol (PVA).

Submerged harvest reduces invasive Typha and increases soil macronutrient availability

We examined how mechanical management of invasive macrophyte, Typha × glauca alters plant-soil interactions underlying carbon processes and nutrient cycling, which are important to wetland function but under-represented in restoration research. In the northern Great Lakes, we compared plant biomass, light transmittance, soil nutrient availability and carbon mineralization rates of Typha-dominated controls with Typha stands harvested above the waterline (harvest) and at the soil surface (submerged harvest). Relative to controls, harvested stands had 50% less litter and twice as much light transmittance to the water surface after one year. However, Typha stems re-grew, and soil nutrient availability rates were similar to controls. Submerged harvest eliminated Typha litter and stems, and increased light transmittance through the water column. P and K soil availability rates were 70% greater with submerged harvest than in controls. Soil C mineralization rates were not affected by treatment (mean ± 1 SE; 40.11 ± 2.48 μg C-CO2 and 2.44 ± 0.85 μg C-CH4 g−1 soil C hr.−1), but were positively correlated with soil Fe availability. While submerged harvest effectively decreased invasive Typha biomass after one year, it increased soil nutrient availability, warranting further examination of macronutrient cycling and export during invasive plant management.

Soil Macronutrient Responses in Diverse Landscapes of Southern Tallgrass to Two Stocking Methods

Macronutrient (N, P, S, K, Ca, and Mg) availability and distribution in soils of grassland ecosystems are affected by diverse factors, including landscape position, climate, and forms of management. This study examined flux in plant-available macronutrients in production-scale (60 to 80 ha) paddocks of southern tallgrass prairie of central Oklahoma, United States, managed (2009–15) under two contrasting stocking methods (continuous yearlong; rotational stocking among 10 sub-paddocks). Macronutrient availability within the 0–7.5 cm and 7.5–15 cm soil depths were determined with sets of anion-cation exchange membrane probes at 16 locations within paddocks, oriented along transects from water sources to far corners. No clear overall effect related to stocking method was recorded for all macronutrient distributions. The only significant stocking method × location interaction occurred for K (p = 0.01). All other macronutrients displayed significant (p &lt; 0.08) location effects that were common across stocking methods. Effects relatable to stocking method occurred in interactions with soil depth or time of year (p &lt; 0.10), but responses of macronutrient flux to stocking method in these interactions varied. Higher flux occurred in available S, Ca, and Mg in proximity (&lt;24 m) to water sources, which may be related to grazing, but local features of the landscape may also have been involved. More attention to landscape features included within paddocks, and standardized organization of water and other features within paddocks, would improve the potential to define grazing effects on macronutrient distribution.