Concentrations Of Most Nutrients Research Articles

Comparing the Nutritional Needs of Two Solanaceae and One Cucurbitaceae Species Grown Hydroponically under the Same Cropping Conditions.

Switching over to closed-loop soilless culture systems, thus preventing pollution of water resources by nitrates and saving water and fertilizers, requires accurate estimations of the mean nutrient-to-water uptake ratios. To contribute to this objective, three fruit vegetable species (tomato, eggplant, cucumber) were grown hydroponically in a floating system under identical cropping conditions to quantify species differences in nutrient uptake. The composition of the nutrient solution used to feed the crops was identical for all species. The total water consumption and the concentrations of most nutrients (K, Ca, Mg, N, P, Fe, Mn, Zn, Cu, B) in the nutrient solution and the plant tissues were measured at crop establishment and at two different crop developmental stages. The obtained data were used to determine the uptake concentrations (UCs) using two mass balance models, one based on nutrient removal from the nutrient solution and a second based on nutrient recovery in the plant tissues. The experiment was conducted in the spring-summer season. The results revealed that the nutrient uptake concentrations were substantially different between species for all nutrients except for N, while there were also significant interactions between the two methods used for their estimation of some nutrients. Thus, the UCs of N, P, Ca, and some micronutrients were significantly higher when its estimation was based on the removal of nutrients from the nutrient solution compared to recovery from plant tissues, presumably because with the first method, losses due to denitrification or precipitation could not be separated from those of plant uptake. The comparison of the three greenhouse vegetables revealed a similar UC for nitrogen, while cucumber generally showed significantly lower UCs for P and for the micronutrients Fe, Zn, and Cu at both cropping stages compared to the two Solanaceae species. The obtained results can be used to precisely adjust the nutrient supply in closed-loop soilless cultivations to the plant uptake thus avoiding both depletion and accumulation of nutrients in the root environment.

Maize experiment in a traditional Zuni agroecosystem: nutrient composition

ABSTRACT Maize has sustained the Zuni and other peoples of the arid American Southwest for more than four millennia. In Zuni dryland agriculture, fields on alluvial fans and other valley-edge landforms are managed to receive supplemental water and nutrients by retaining storm runoff and associated sediment and organic material transported from adjoining uplands. An experiment with Zuni blue maize (Zea mays L.) and commercial hybrid maize was conducted in two Zuni fields to study traditional maize and its productivity as part of a larger study of Zuni agroecosystems. Following a closely related paper on maize growth and productivity, studies of maize nutrient composition and quality are presented here. More nutrient differences occurred between Zuni and hybrid maize than between runoff and other treatments. Zuni grain had higher concentrations of more nutrients than hybrid maize, and for several elements, there was an inverse pattern in grain vs. leaf nutrient concentration between cultivars. Zuni grain had a higher N (protein) concentration than hybrid maize, and a higher proportion of N in grain vs. leaf, indicating an ability to partition more N and other nutrients into grain. Parallel differences in maize and soil N and P were found between the two fields, though the cultivars had different P content patterns. Overall, agronomically sufficient concentrations of most nutrients were present across cultivars and treatments. Long-term production and nutrient management of maize grown without conventional irrigation or fertilization reflect a traditional agroecosystem that incorporates sustainable practices intended to maintain productivity with conservation of soil and water resources.

New oil and forage producing plant species evaluated on phosphorus doses and row spacing

Nicandra physaloides is a non-domesticated plant species, a potential oil and forage supplier. Its adaptation to the agricultural production system needs to be investigated. The aim of this study was to evaluate the response of N. physaloides to eight treatments resulting from the factorial combination of two spacings (0.25 and 0.50 m) and four phosphate fertilizers (0, 40, 80, 160 kg ha−1 of P2O5). Row spacing did not influence grain yield, oil content, or plant growth. Grain yield is influenced by phosphate fertilization, increasing at the rate of 1.33 kg of grains for each kilogram of P2O5 supplied, with a maximum yield of 581 kg ha−1 in the fertilization of 160 kg ha−1 of P2O5. Phosphate fertilization also influences shoot growth, with an increase of 0.26 g plant−1 for each kilogram of P2O5 supplied, with a maximum production of 7.8 t ha−1. The concentration of potassium, sulfur and copper in the aerial part of plants is influenced by phosphate fertilization. The greater spacing results in a greater concentration of most nutrients in the biomass. The average oil content in the seeds is not influenced by spacing or phosphorus fertilization, being estimated at 16.32% of the dry mass of the grains.

NPK Fertilization of Serianthes Plants Influences Growth and Stoichiometry of Leaf Nutrients

The genus Serianthes has not received adequate research attention, leaving large gaps in the knowledge required to inform conservation decisions. For example, nutrient management protocols are not understood due to lack of research. Serianthes grandiflora, Serianthes kanehirae, and Serianthes nelsonii plants were grown in container culture to determine the influence of increasing edaphic nitrogen (N), phosphorus (P), or potassium (K) content on stem growth and leaf nutrient relations. Addition of N alone increased leaf N, stimulated stem height and diameter growth, increased leaf number, and reduced leaf tissue concentrations of most nutrients including P and K. Addition of K alone increased leaf K, did not influence stem growth, did not reduce N or P concentration, but caused substantial changes in leaf tissue stoichiometry. Addition of P alone increased leaf P, did not influence stem growth, did not reduce leaf N or K concentration, and exerted minimal influence on concentrations and stoichiometry of other nutrients. The results indicate that single element P fertilization may be used to mitigate P deficiencies of Serianthes saplings without the risk of causing substantial nutrient imbalances. This knowledge may be used to inform nutrient management decisions in Serianthes conservation projects.

A statistical framework for testing impacts of multiple drivers of surface water quality in nearshore regions of large lakes

In nearshore regions of large freshwater ecosystems, complex biophysical processes across large geographic regions, combined with the common logistical challenges of data collection by multiple research agencies and shifting monitoring survey designs over time, present challenges for detecting and managing the influence of multiple sources of nutrients and pollution. We present a statistical framework using linear mixed models (LMMs) to test impact of multiple drivers on nearshore water quality of large lakes. Under this framework, we analyzed a 12-year dataset of water quality variables that were measured from a nearshore region along the Canadian shoreline of Lake Ontario (~86 km2), near Pickering and Ajax. Spatial interpolation showed that almost all water quality parameters decreased in magnitude from the shoreline to the offshore. Two exceptions to this nearshore-offshore gradient occurred in a region that extended ~8 km southwest from the outfall of the Duffin Creek Water Pollution Control Plant (DCWPCP) where ammonia + ammonium (NH3+4) increased and pH decreased slightly. Other LMMs combined explanatory factors into major groups (geographic proximities to shoreline tributary mouths and stormwater drains [inflows], tributary discharges, discharge or loading from the DCWPCP, and climate factors). These models showed that geographic proximity to shoreline inflows and/or tributary discharges were the most important drivers for most water quality parameters including concentrations of phosphorus, a key variable for regulating proliferation of harmful algae blooms and nuisance benthic algae in the Great Lakes. Air temperature was correlated with decreased phosphorus concentrations and nitrate + nitrite, whereas total precipitation and snow were correlated with increased concentrations of most nutrients except NH3+4, which was negatively correlated with duration of lake ice cover in winter. Our framework highlights how influence of individual nutrient sources can be distinguished from climate factors within a dominant nearshore-offshore gradient in water quality within nearshore regions of large lakes.

Abatement of water nutrient load in a fish culture system using the aquatic trophic levels.

Integrated aquatic systems are used to decrease the nutrient loads of effluents negating the negative environmental impacts of aquacultural systems. Some of these systems have a separate algae compartment requiring high maintenance. An integrated culture system was set up with different trophic levels: algae, zooplankton, and fish. The algal tank was in-line with the fish and zooplankton components to minimize the maintenance required for the algae. A control flow-through system was also set up without the algae and zooplankton compartments. The systems were run for 6weeks, and water temperature, pH, dissolved oxygen, NO3 , NO2 , NH4 , and PO4 concentrations were measured. A removal rate was determined for each water parameter and the densities of the algae and zooplankton species were measured in each compartment of the integrated system. The concentrations of most nutrients in the integrated system were similar to those of the control system. The density of algae increased during the first 3 weeks and remained almost stable until the end of the experiment. There was an inverse relationship between the densities of two zooplankton suggesting compensatory effects on the control of the algal bloom. The integrated system improved water quality with minimal algal culture maintenance, water exchange, and no fish mortality. PRACTITIONER POINTS: An integrated system could effectively reduce the nutrient load of water. Water replacement in the integrated system was significantly lower than that of a flow through system. The inline plankton culture tanks decreased greatly the maintenance of the system.

Ensiling of maple leaves and its use in winter nutrition of mantled guereza (Colobus guereza).

Young leaves are favored by mantled guereza (Colobus guereza) and the gastrointestinal tract of this species is well adapted to such a high fiber diet. Fresh maple leaves are often used in the diets for guereza in captivity but their use in winter feeding time is limited. The aim of the study was to evaluate the effect of additives on chemical composition and fermentation parameters of maple leaf silage, as well as inclusion of maple leaf silage in the diet for mantled guereza on feed and nutrient intake. Maple leaves were ensiled without additives (MLS), with a mixture of bacterial inoculants (MLS + BI) and with carrot additives (MLS + C). The chemical composition and fermentation parameters were determined in fresh and ensiled material. A group of seven mantled guerezas were fed a standard diet, and afterwards shifted to a diet with maple leaf silage (contained 20% of MLS; as fed). Each diet was fed for 7 days when the feed and nutrient intake were measured. The ensiling process did not change the concentration of most nutrients compared to the fresh material. The inclusion of leaf silage increased dry matter intake by guereza (125.3 vs. 163.3 g dry matter/day). Therefore, higher nutrient intake (crude protein, NDF, ADF) was observed when maple leaf silage was included in the diet. In conclusion, the ensiling process (even without additives) proved to be a good conservation method for maple leaves. Furthermore, inclusion of maple leaf silage in the winter diets for guereza, and possibly other folivorous primates, may increase dry matter and nutrients (particularly fiber) intake.

Nutritional status of ‘Hass’ and ‘Fuerte’ avocado (Persea americana Mill.) plants subjected to high soil moisture

In this study, the effect of increased soil moisture on the nutritional status of two key commercial avocado (Persea americana Μill.) cultivars, ‘Fuerte’ and ‘Hass’, was examined. The results revealed that prolonged exposure of plants to high soil water content conditions (waterlogging) reduced the total nutrient content (absolute quantity) of almost all of the nutrients in scion’s tissues (leaves and stems) of both cultivars. The decrease of nutrient content in the ‘Fuerte’ leaves was more prominent/severe compared to the ‘Hass’ leaves, which could be the outcome of the reported higher sensitivity of the cultivar to soil waterlogged conditions in previous studies. Interestingly, the inability of ‘Fuerte’ avocado plants to withstand high soil moisture conditions was not reflected in the relative concentrations of most nutrients, both in leaves and stems. Indeed, significantly higher concentrations of P, K, B, Fe, and Zn were found in the leaves of ‘Fuerte’ waterlogged plants than in well-watered ones. This fact reveals that under marginal/stressful conditions, like waterlogging, nutrient concentration in tissues does not reflect potential negative effects on total nutrient uptake of avocado plants, obviously due to concentrated nutrient phenomena primarily created by the stress-dependent growth inhibition. Therefore, total nutrient content is proposed as a more representative indicator for assessing plant response to waterlogged conditions.

Silicon stimulates initial growth and chlorophyll a/b ratio in rice seedlings, and alters the concentrations of Ca, B, and Zn in plant tissues

Silicon (Si) is considered a beneficial element for plants due to the far-reaching benefits it confers, including enhanced growth, yield, and crop quality, as well as stress resistance. In this study, we evaluated the effect of Si during germination and initial growth (0.0, 0.5, 1.0, or 1.5 mM Si) and during vegetative growth (0, 1, 2, or 3 mM Si) in rice (Oryza sativa) cv. Morelos A-98. Si did not affect germination but stimulated seedling height, root length, number of roots, as well as fresh and dry biomass weight of shoots and roots during initial growth. During vegetative growth, the application of 3 mM Si significantly increased the chlorophyll a/chlorophyll b ratio, but no major changes were observed either in growth or in concentrations of most nutrients, with the exception of Ca (which increased with 3 mM Si), and B and Zn (which decreased in the presence of Si). In conclusion, applying Si had positive effects during the initial stage of growth, increasing seedling height, root length, root number, and fresh and dry biomass weight. Under our experimental conditions, Si did not affect germination and vegetative growth, but increased Ca concentrations and decreased B and Zn concentrations.

Responses of plant biomass and nutrients to fire vary with functional group and slope aspect in a semiarid restored grassland on the Loess Plateau

Fire and topography both have important impacts on grassland ecosystems. Still, the interactive effects between them on plant nutrients remain unclear, hindering the precise prediction of fire effects at larger spatial scales. Here, we examined the effects of fire on aboveground biomass, as well as on carbon and nutrient concentrations, in a semiarid restored grassland (under grazing exclusion) on the Loess Plateau. We compared these effects between graminoid and forb, as well as at the total community level. The influence of slope aspect and slope position on these effects were also examined. Fire significantly increased the aboveground biomass of graminoid but did not affect that of forb. Fire significantly decreased the concentrations of most nutrients in aboveground biomass. Graminoid on the north-facing slope had higher dominance and aboveground biomass but lower nutrient concentrations than that on the south-facing slope. Forb on the north slope had similar aboveground biomass and nutrient concentrations but lower dominance than that on the south slope. Furthermore, the effects of fire on nutrient concentrations in graminoid varied with slope aspect, with more fire-induced decrease in nitrogen and potassium but less decrease in carbon on the north slope than that on the south slope. However, the effects of fire on nutrients in forb and in total community were not varied with slope aspect. Slope position had minimal effect on aboveground biomass and nutrient concentrations and their responses to fire. These results indicate that slope aspect and fire have interactive effects on plant nutrient concentrations in semiarid restored grasslands on the Loess Plateau, and thus should be considered when predicting nutrients cycling in grasslands.

Degradation of soil nutrients and slow recovery of biomass following shifting cultivation in the heath forests of Sarawak, Malaysia

Heath forests which are tropical forests on sandy soils are widely distributed in Borneo and provide many ecosystem services, such as carbon storage and non-timber forest products. Over the past several decades, such forests have been disturbed by non-traditional shifting cultivation, which is usually conducted in unsuitable land with short fallow duration. Anthropogenic disturbances in forests growing on sandy soils that have low nutrient retention capacities may promote further reductions in soil fertility. Long-term monitoring of soil nutrients and biomass accumulation is rare in degraded tropical rainforests growing on sandy soils despite the known negative effects of non-traditional shifting cultivation practices on soil fertility, vegetation and biomass recovery, and the growth of trees planted to rehabilitate forests. The objective of the current study was therefore to elucidate changes in soil fertility and biomass recovery potential in degraded forests on sandy soils in Borneo. We monitored soil nutrients and chemical properties in fifty-four 12 × 12 m plots located on different topographical positions along upper and lower slopes. Samples were collected in plots aged 7 and 14 years after abandonment of shifting cultivation. The biomass of secondary forest trees in all plots 12 years after the abandonment was also measured to determine the relationship between biomass accumulation and changes in soil nutrients. We found that soil pH and cation exchange capacity, and the concentrations of most nutrients, including nitrogen, magnesium, and phosphorus, had decreased significantly 7–14 years after abandonment; biomass accumulation in the plots was also limited 12 years after abandonment (<0.8 Mg ha−1 year−1). These changes in soil traits within the study plots were similar regardless of topographical position, and the changes were not related to the amount of biomass. Soil nutrients in the plots may have leached out as a result of removal of thick root mats in the surface soil, high sand content, and large amounts of rainfall in the area rather than uptake by recovering trees. These results indicate that it may be difficult to recover soil fertility on steep slopes in sandy soil conditions because of high leaching rates and erosion when the soil surface layer is destroyed by shifting cultivation. It is therefore important to carefully manage shifting cultivation practices in tropical forests on sandy soils in Borneo.

Nutrient retention and release in coarse woody debris of three important central European tree species and the use of NIRS to determine deadwood chemical properties

BackgroundCoarse woody debris (CWD) is very important for forest ecosystems, particularly for biodiversity and carbon storage. Its relevance as a possible reservoir and source of nutrients is less clear, especially in central Europe.MethodsBased on a chronosequence of known ages of logs, we analyzed the nutrients stored in CWD of Fagus sylvatica, Picea abies, and Pinus sylvestris at different sites in Germany. To quantify nutrient concentrations, we assessed the use of Near Infrared Reflectance Spectroscopy (NIRS) to determine the chemical properties of CWD.ResultsNIRS models were suitable to predict concentrations of C, N, P, lignin and extractives. Concentrations of most nutrients increased with mass loss, with the exception of potassium, which decreased for beech and pine and remained relatively constant for spruce. The highest nutrient concentrations (N, P, S, Ca and Mn, except Mg and K) were generally observed in highly decomposed spruce logs. The net effect of decreasing CWD mass and increasing nutrient concentrations was either a decreasing (N, P and K in beech; P, Mg, K and Mn in pine), constant (S, Ca and Mg in beech; N, S and Ca in pine) or increasing amount of nutrients (N, P, S and Ca in spruce; Mn in beech) in the logs over the course of decomposition. The C/N ratio decreased for all tree species, most markedly for spruce from ca. 1000 at the beginning of the decomposition process to 180 at 36 years. The N/P ratio converged to a value of about 30 for all three species. Lignin concentrations increased for spruce and beech and remained constant for pine.ConclusionsOur results indicate that most nutrients remain in CWD for long periods. Nutrients may be used and cycled by microorganisms within CWD, but with the exception of P (in beech), Mg (in pine) and K (in beech and pine), there appears to be little net nutrient export until two thirds of the mass is lost. Instead, N, P, S and Ca were accumulated in spruce logs, indicating that CWD became a net sink rather than a net source of some nutrients for several decades.

Geo‐ecological studies on two ultramafic sites in western Ireland

AbstractUltramafic soils are found in many sites around the world where they can vary from exceptionally barren to reasonably fertile. Two ultramafic sites in western Ireland were studied: grassland at Dawros, County Galway and grassy heath near the base of Croagh Patrick, County Mayo. Rock and soil chemistry was examined along with foliar nutrients (at Dawros only). Ellenberg reaction values of all plant species recorded were determined. Two bioassays were conducted to determine relative differences in fertility between ultramafic and adjacent non‐ultramafic soils and to assess nutrient limitation in the Croagh Patrick soil. Both soils showed many of the chemical characteristics typical of other ultramafic sites including a moderately high nickel concentration; in general, soil metal concentrations were higher in Dawros soils. However, nitrogen, phosphorus and calcium (with a calcium:magnesium ratio c. 0.6) were all at high concentrations at Dawros leading to a fertile grassland with both calcicole and calcifuge species present spanning six Ellenberg reaction values. Foliar nutrient concentrations were not unusual although calcium:magnesium ratios were approximately double in non‐ultramafic soils compared to ultramafic soils. Croagh Patrick soil had lower concentrations of most nutrients and presented a grassy heath vegetation with more acidic reaction values. The bioassays showed plant growth to be reduced in this soil relative to that at Dawros and to be clearly limited by phosphorus availability. Whilst these two Irish ultramafic sites do not show the extreme features associated with other sites across the world they indicate the global diversity of serpentine ecologies.

Productivity and nutrient concentration in spineless cactus under different fertilizations and plant densities

The objective was to evaluate the productivity and nutrient concentration in spineless cactus ‘Miuda’ (Nopalea cochenillifera Salm Dyck) under levels of nitrogen (N) fertilization (0, 150, 450 and 600 kg N ha-1 year-1), P fertilization (0 and 150 kg P2O5 ha-1 year-1), plant densities (5,000 and 40,000 plants ha-1) in two sites (Caruaru and Sao Bento do Una). The productivity was greater in plots with 40,000 plants ha-1, regardless of the site, with average of 16.8 and 7.2 t DM ha-1 two years-1, for 40,000 and 5,000 plants ha-1, respectively. In plots with 5,000 plants ha-1, nitrogen fertilization did not affect productivity, however, there was a linear increase in plots with 40,000 ha-1 plants. The plant N concentration increased with nitrogen fertilization and ranged from 7.3 to 9.9 g kg-1. The plant phosphorus (P) concentration was influenced by the interaction between all the factors evaluated and reduced until estimated fertilization of 322 kg N ha-1 in plots with 40,000 plants ha-1 and 150 kg P ha-1 and only in Sao Bento do Una, with P concentration of 1.19 g kg-1. Nitrogen fertilization increased N concentration in cladodes and productivity when using high plant density. The increase in planting density increases productivity and reduces the concentration of most nutrients, except sulphur (S).

Mycorrhizal associations and soil properties of native Allanblackia stuhlmannii stands in the Eastern Usambara Mountains, Tanzania

AbstractAllanblackia stuhlmannii is a tree species currently under domestication. Potential mycorrhizal relationships of A. stuhlmannii and soil properties of native stands were investigated to determine the soil–environmental requirements of the species. Roots and soil samples were collected from five sites with A. stuhlmannii stands along an altitudinal transect in Amani Nature Reserve, Tanzania. Mycorrhizal status was investigated by combining microscopy with molecular analysis of the fungal communities. Soil adjacent to the A. stuhlmannii seedlings was analysed for physical and chemical properties and the sites were characterised. We showed that A. stuhlmannii form symbiosis with arbuscular mycorrhizal fungi, and that there was a diverse microbiome associated with the roots. The soils, classified as Ferralsol and Acrisol, were very well drained, had a pHCaCl2 generally at or below 4, high exchangeable acidity and content of sesquioxides and low effective cation exchange capacity and concentrations of most nutrients. We conclude that A. stuhlmannii is tolerant to high Al availability and possesses mechanisms for acquisition of P and other macronutrients at low soil availability, possibly through mycorrhizal symbiosis. However, being adapted to low‐pH soils, it may be less efficient in acquiring Fe, Mn and/or Zn at higher soil pH. Thus, it may be most suited to introduction on farms situated on acid soils.

Improving performance of olive trees by the enhancement of key physiological parameters of olive leaves in response to foliar fertilization

Most of the studies investigated the effects of nutrient-based fertilizers on olive fruits and oil quality; few studies have been interested in the modification of the chemical composition of olive leaves in response to fertilization. Thus, the current study aims to examine the effects of foliar fertilization on the mineral profile of olive leaves as well as the concentrations of chlorophyll, antioxidants (phenolic compounds) and carbohydrates. Experimentation consists of the annual application of six treatments during two successive growing seasons (2009–2010): TC (untreated trees), P1 (nitrogen-based fertilizer), P2 (contains boron, magnesium and manganese), P3 (phosphorus and potassium based fertilizer), P4 (rich in calcium and phosphorus), T5 (P1 and P2 application) and T6 (P1, P2, P3 and P4 application). At the end of the experiment, mineral analysis of olive leaves showed an increase in the concentrations of most nutrients which induced changes in biochemical composition: an increase of chlorophyll content, a reduction of total phenols and oleuropein concentrations coupled with an increase of hydroxytyrosol level. Moreover, an increase of total sugar content and most individual sugars, principally translocated forms of sugars (mannitol, sucrose and raffinose), was also observed. The accumulation of these key physiological parameters by foliar fertilization suggests an improvement of physiological performance and photosynthetic capacity of olive trees. Moreover, from a biological point of view, the results of the study revealed the possibility to improve plants of medicinal interest by enhancing the accumulation of some bio-active compounds, such as hydroxytyrosol and mannitol, via foliar nutrient supply.

Rainfall-induced nutrient losses from manure-fertilized farmland in an alluvial plain

Nutrient transport and loss in farmlands are affected by factors such as land cover, fertilization, soil type, rainfall, and management practices. We investigated the temporal and spatial changes in macronutrient transport and loss after fertilization and precipitation in manure-fertilized eggplant farmland in an alluvial plain. Upon adding topical fertilizer, concentrations of most nutrients in runoff and groundwater increased, and nitrogen runoff increased from 22.11 to 35.81 kg/ha, although eggplant yield did not increase correspondingly. Incorporation of fertilizer by plowing reduced nutrient losses (nitrogen runoff/fertilizer decreased from 18.40 to 12.29 %). Measurements taken along the nutrient transport route (runoff, drainage ditch, groundwater, river water, and finally rainfall) revealed that concentrations of most nutrients declined at each stage. Nutrient characteristics varied by transport, and the forms of nitrogen and phosphorus differed greatly between runoff and groundwater (nitrate/nitrogen in runoff was ~43.49 %, while in groundwater ~5.41 %). Most nutrient concentrations in runoff decreased greatly during the planting season (total nitrogen decreased from 62.25 to 4.17 mg/L), correlated positively with temperature and stage of plant growth, but little temporal change was observed in groundwater. This field investigation during one planting season exemplifies the basic principles of nutrient loss and transport from manure-fertilized farmland in an alluvial plain.

Uptake and Partitioning of Nutrients in Blackberry and Raspberry and Evaluating Plant Nutrient Status for Accurate Assessment of Fertilizer Requirements

Raspberry and blackberry (Rubus sp.) plantings have a relatively low nutrient requirement compared with many other perennial fruit crops. Knowledge of annual accumulation of nutrients and periods of rapid uptake allows for better management of fertilization programs. Annual total nitrogen (N) accumulation in the aboveground plant ranged from 62 to 110 and 33 to 39 lb/acre in field-grown red raspberry (Rubus idaeus) and blackberry (Rubus ssp. rubus), respectively. Research on the fate of applied 15N (a naturally occurring istope of N) has shown that primocanes rely primarily on fertilizer N for growth, whereas floricane growth is highly dependent on stored N in the over-wintering primocanes, crown, and roots; from 30% to 40% of stored N was allocated to new growth. Plants receiving higher rates of N fertilizer took up more N, often leading to higher N concentrations in the tissues, including the fruit. Reallocation of N from senescing floricanes and primocane leaves to canes, crown, and roots has been documented. Accumulation of other macro- and micronutrients in plant parts usually preceded growth. Primocanes generally contained the highest concentration of most nutrients during the growing season, except calcium (Ca), copper (Cu), and zinc (Zn), which often were more concentrated in roots. Roots typically contained the highest concentration of all nutrients during winter dormancy. Nutrient partitioning varied considerably among elements due to different nutrient concentrations and requirements in each raspberry and blackberry plant part. This difference not only affected the proportion of each nutrient allocated to plant parts, but also the relative amount of each nutrient lost or removed during harvest, leaf senescence, and pruning. Macro- and micronutrient concentrations are similar for raspberry and blackberry fruit, resulting in a similar quantity of nutrient removed with each ton of fruit at harvest; however, yield may differ among cultivars and production systems. Nutrient removal in harvested red raspberry and blackberry fruit ranged from 11 to 18 lb/acre N, 10 to 19 lb/acre potassium (K), 2 to 4 lb/acre phosphorus (P), 1 to 2 lb/acre Ca, and 1 to 4 lb/acre magnesium (Mg). Pruning senescing floricanes in August led to greater plant nutrient losses than pruning in autumn. Primocane leaf nutrient status is often used in nutrient management programs. Leaf nutrient concentrations differ with primocane leaf sampling time and cultivar. In Oregon, the present recommended sampling time of late July to early August is acceptable for floricane-fruiting raspberry and blackberry types, and primocane-fruiting raspberry, but not for primocane-fruiting blackberry, where sampling leaves on primocane branches during the green fruit stage is recommended. Presently published leaf tissue standards appear to be too high for K in primocane-fruiting raspberry and blackberry, which is not surprising since the primocanes are producing fruit at the time of sampling and fruit contain a substantial amount of K.

Effects of barley-based diets with 3 different rumen-degradable protein balances on performance and carcass characteristics of feedlot steers

ABSTRACT The objective of this experiment was to determine the effect of varying the dietary degradable protein balance (DPB) on finishing cattle performance. Crossbred yearling steers (n = 300; BW = 460 ± 26 kg) were allotted to 12 pens (25 steers/pen) and fed barley grain-based finishing diets with negative DPB (− 12 g/kg of DM), neutral DPB (0 g/ kg of DM), or positive DPB (14 g/kg of DM). The diet with negative DPB contained 88.3% barley grain and 4.7% barley silage. For the neutral and positive DPB diets, 11 and 22% of dietary barley grain, respectively, was replaced by wheat-based dried distillers grains with solubles. Increasing DPB in the diet increased the concentration of most nutrients linearly (P 0.05) starch (88.3 ± 1.36%), whereas protein supply in the small intestine (78.8 to 91.2 g/kg of DM) increased (P 0.05) among treatments. In conclusion, when diets were formulated to meet or exceed nutrient requirements for targeted performance, changing dietary DPB from − 12 to 14 g/kg had no major effect on animal performance and carcass characteristics.

Harvesting as an Alternative to Burning for Managing Spinifex Grasslands in Australia

Sustainable harvesting of grasslands can buffer large scale wildfires and the harvested biomass can be used for various products. Spinifex (Triodiaspp.) grasslands cover ≈30% of the Australian continent and form the dominant vegetation in the driest regions. Harvesting near settlements is being considered as a means to reduce the occurrence and intensity of wildfires and to source biomaterials for sustainable desert living. However, it is unknown if harvesting spinifex grasslands can be done sustainably without loss of biodiversity and ecosystem function. We examined the trajectory of plant regeneration of burned and harvested spinifex grassland, floristic diversity, nutrient concentrations in soil and plants, and seed germination in controlledex situconditions. After two to three years of burning or harvesting in dry or wet seasons, species richness, diversity, and concentrations of most nutrients in soil and leaves of regenerating spinifex plants were overall similar in burned and harvested plots. Germination tests showed that 20% of species require fire-related cues to trigger germination, indicating that fire is essential for the regeneration of some species. Further experimentation should evaluate these findings and explore if harvesting and intervention, such as sowing of fire-cued seeds, allow sustainable, localised harvesting of spinifex grasslands.