Phosphorus Balance Research Articles

Modeling whole farm profitability and environmental performance of four alfalfa‐grass binary mixtures in eastern Canadian dairy farms

AbstractForages are a major source of nutrients for milk production, but little is known about the effects of forage species on whole‐farm profitability and environmental performance. Using a whole‐farm approach, the N‐CyCLES (Nutrient‐Cycling Crops‐Livestock‐Environment‐Soil) optimization model, and experimentally measured data, this study aimed to compare the profitability and environmental performance of dairy farms when four alfalfa (Medicago sativa L.)‐grass binary mixtures harvested and stored as silage and hay are used in ration formulation of heifers and lactating and dry cows: (a) alfalfa‐timothy (Phleum pratense L.) (Al+Tim), (b) alfalfa‐tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] (Al+TF), (c) alfalfa‐meadow fescue fescue [Schedonorus pratensis (Huds.) P. Beauv.] (Al+MF), and (d) alfalfa‐meadow bromegrass (Bromus biebersteinii Roem. & Schult.) (Al+Bro). Simulations were conducted on two virtual eastern Canadian dairy farms: southwestern (SWQ) and eastern Quebec (EQ). Comparisons were based on net income, greenhouse gas emissions, and nutrient balances. In SWQ, Al+Bro and Al+Tim led to the highest net income, but only slight differences were calculated between the four mixtures (maximum difference of 1.4%). In EQ, results suggested that Al+TF is the most viable alternative to Al+Tim mixtures as it allowed the farm to reach the highest profit (maximum difference of 8%). The choice of grass in alfalfa‐grass binary mixture had little impact on the farm's total greenhouse gas emissions: the lowest total greenhouse gas emissions were with Al+ MF in SWQ and with Al+TF in EQ. In SWQ, phosphorus balance was low for the four mixtures and the lowest nitrogen balance was reached with Al+MF and Al+Tim. Finally, in EQ, the lowest phosphorus balance was reached with Al+MF, whereas the lowest nitrogen balance was reached with Al+Bro. In conclusion, despite slight differences, all grass species tested allowed the farm to reach similar profits and environmental performance.

On-farm assessment of the phosphorus balance of paddy soil fertilized with cow dung compost in mixed crop–livestock systems and with rice straw in conventional practice in Yamagata, Japan

ABSTRACT Rice straw (RS) and cow dung compost (CDC) are good sources of phosphorus (P) to support rice production. Our previous research found that CDC application in mixed crop-livestock systems supplied more total P to the paddy soil than RS, but available P did not differ significantly between the CDC and RS fields. To explain these results, we investigated the soil total P and soil P balance in RS and CDC fields. From the 79 paddy fields managed by farmers in Mamurogawa, Yamagata, Japan, which were investigated in previous research, we selected 10 pairs of adjacent RS and CDC fields, then measured soil total P, P inputs (RS or CDC and fertilizer), and P outputs (plant uptake and leaching), and calculated the resulting soil P balance. The result showed that soil total P did not differ significantly between treatments. The higher P input from CDC would let farmers apply less fertilizer P in CDC fields than in RS fields, but there was no significant difference in total P input between treatments. Plant P uptake and leaching did not differ significantly between treatments. The soil P balance was positive (i.e., net P accumulation) and did not differ significantly between treatments. The lack of differences in the total P input, total P output, and soil P balance between treatments explains the non-significant differences in soil total P and available P.

Effects of Farming Practices on Soil Nitrogen and Phosphorus Concentrations and Its Loss in the Drawdown Area of the Tributary Embayment of the Three Gorges Reservoir

As the Three Gorges Reservoir (TGR) periodically operates at low water levels, its drawdown area has been utilized for cultivation by local farmers due to the overlap of the non-inundated period and the crop-growth period. However, traditional agricultural planting may affect the aquatic environment of the TGR area. To explain the effects of agricultural farming and abandoned farming on the water environment, a study was conducted in the drawdown area in an embayment of the Pengxi River (a tributary of the TGR). Corn, potato, and peanut fields were investigated for nitrogen and phosphorus content in surface soil, during the farming period (March to September 2018) and the conversion period (March to September 2019). Nitrogen and phosphorus balance models were constructed for farmland and abandoned farmland, to compare and analyze the budgets and loss risk of nitrogen and phosphorus from soil in the drawdown area. The results showed that the ammonia nitrogen (NH4+-N), total phosphorus (TP), and inorganic phosphorus (IP) content of soil in the corn field varied significantly across different planting periods. The concentrations of ammonium nitrogen and nitrate nitrogen (NO3--N) were significantly higher in farmland soil than in abandoned farmland soil, and the concentrations of total phosphorus (TP), inorganic phosphorus (IP), and calcium-bound phosphorus (Ca-P) were significantly lower in farmland soil than in abandoned farmland soil. The different soils were ranked according to the intensity of nitrogen and phosphorus surplus as follows:corn field>potato field>peanut field. The apparent surplus values in the different farmland soils were 76.89 kg ·hm-2(corn field), 51.92 kg ·hm-2(potato field), and 43.74 kg ·hm-2(peanut field) for nitrogen, and 79.69 kg ·hm-2(corn field), 75.76 kg ·hm-2(potato field), and 17.78 kg ·hm-2(peanut field) for phosphorous. Overall, the surplus intensities of nitrogen and phosphorus in all three croplands were higher than the respective risk thresholds, indicating potential nitrogen and phosphorus pollution in the three farmland types. Agricultural farming in the drawdown area may therefore increase the risk of nitrogen and phosphorus loss and is not conducive to the protection of the aquatic environment.

Spent marigold flower meal as an alternate feed for goats.

This research trial is aimed to study the nutritional qualities and significance of feeding spent marigold flower meal (SMFM) in goats. SMFM and diet containing iso-nitrogenous concentrate mixture with different levels of spent marigold flower meal (0-30%) were studied for in vitro degradation. Depending upon the in vitro results, concentrate mixture containing 15% level of SMFM was selected for in vivo trial. In vivo studies were conducted for a period of 60days, and 12 local, non-descript, adult male goats (10-14months age; 31.09 ± 2.91kg body weight) were randomly assigned to two groups and were fed on ad libitum wheat straw with either conventional (control) or SMFM containing concentrate mixture (treatment). Results of the study showed that there was no variation in body weight of the goats between periods and between groups. DM and OM intake along with their digestibility were similar among the two groups. The digestibility of all other nutrients was comparable between the two groups. Nitrogen, calcium and phosphorus balance were positive in both the groups without any significant disparity. Moreover, experimental goats did not differ in biochemical parameters, without any significant difference between periods and dietary treatments except AST level which was significantly higher (P > 0.05) in treatment group. So, this study successfully demonstrates that SMFM could be incorporated in the concentrate mixture, up to 15% without any discernable difference in the performance of goats.

Neuro fuzzy evaluation of circular economy based on waste generation, recycling, renewable energy, biomass and soil pollution

In a closed loop structure, the circular economy reflects a concept for converting material and energy wastes into capital for other purposes. The circular economy's key goal is to reduce energy and material waste. The best-case scenario will be to eliminate wastes and repurpose them, which is one of the key goals of the circular economy. One of the most important purposes of incorporating of circular economy are decreasing of environmental pollution and improving of sustainably development. The sustainably development could be represented by gross domestic product (GDP). The main goal of the study was to analyze the effect of waste generation, recycling, renewable energy, biomass and soil pollution on the GDP. For such a purpose adaptive neuro fuzzy inference system (ANFIS) was implemented since the methodology is suitable for statistical investigation of strongly nonlinear data sample due to features of fuzzy logic system. The combination of generated municipal waste, renewable energy supply and phosphorus balance per hectare represents the most influential combination for GDP prediction. The obtained results could represent the best practices for implementation of circular economy concept.

Ultrasound-assisted preparation of calcium malate and its absorption.

In this experiment, response surface methodology was used to study the preparation of malic acid calcium salt from bovine bones assisted by ultrasonication. The results showed that the optimum conditions for ultrasound-assisted preparation of calcium malate from bovine bone were as follows: solid-liquid ratio 1:15, solid-acid ratio 1:1.5, ultrasonic power 200 W, ultrasonic temperature 35°C, and ultrasonication time 17 min. The efficiency of calcium recovery was 66.16%, and the purity was 92.54%. After three ultrasonic treatments of 17 min each, the calcium malate conversion rate of bovine bone reached 95.73%. Animal experiments showed that feeding bovine bone-derived calcium malate significantly increased alkaline phosphatase (ALP) activity and bone calcium content, reduced tartrate-resistant acid phosphatase (TRAP) activity, and maintained the balance of serum calcium and phosphorus. These results indicated that the ultrasonic method effectively ionized calcium in bovine bone, which provides a reference point for the industrial production of calcium products with bovine bone as the raw material.

Dissolved organic carbon drives nutrient cycling via microbial community in paddy soil

Microbial mediated iron cycling drives the biogeochemical cycling of carbon, nitrogen, sulfur, and phosphorus. However, the fate of the microbial community and the relative metabolic pathways in paddy soil after the addition of biogas slurry are poorly understood. In this study, the response of functional genes was investigated by growing one-season rice in paddy soils in a pot experiment. Seven treatments were prepared: 1) control (CK); 2) organic carbon (OC); 3) fertilizer (F); 4) 5% of biogas slurry (B05); 5) 10% of biogas slurry (B10); 6) 15% of biogas slurry (B15); 7) 20% of biogas slurry (B20). In the biogas slurry treatments, Geobacter increased more than in the other treatments during rice growth, which were structured by TOC. Particularly, in the B10 treatment, the relative abundance of Geobacter was 1.6 and 14.8 times higher than that of CK at the heading and mature stages, respectively. At the heading stage, the addition of biogas slurry and OC shifted the microbial phosphorus-transformation communities differently. There were no significant differences in the carbon, nitrogen, and sulfur metabolic pathways between the two treatments. At the mature stage, the carbon: nitrogen: phosphorus balance was significantly influenced by the regulation of functional gene expression and metabolic activities. These findings provide insight into the key factors affecting carbon, nitrogen, sulfur, phosphorus, and iron during rice growth after carbon inputs.

Phosphorus balance in a tropical shallow urban pond in Southeast Brazil: implications for eutrophication management

ABSTRACT A detailed mass balance that evaluates nutrient inputs and outputs is fundamental to determining the most promising strategies to mitigate eutrophication and its undesirable effects. However, such analyses are rare in Brazilian urban ponds where water quality impairment remains a significant issue. We performed a mass balance to identify the main phosphorus (P) sources in a hypereutrophic tropical shallow urban pond. We used the PCLake model to estimate the P loading required to reduce phytoplankton biomass. The water column was considered the primary unit in the model. The P balance was calculated from external inputs, internal inputs from bed sediment to the water column, and outputs from the water column through surface water outflow and to the bed sediments over a full hydrological year. The total P input into the pond water (external and internal) was 35.3 mg m−2 d−1 and the output was 35.2 mg m−2 d−1. The P balance revealed that contributions to the water column from external and internal sources were 82.5% and 17.5%, respectively. Birds were the main contributor to P input (76.0%). The highest P loss from the water column was to the sediment (97.6%). Most of the P leaving the water column to the sediment was retained in the sediment, and part was returned to the water column through internal loading. Measures to reduce eutrophication in this pond should focus on integrated management to decrease both the external and internal P sources by managing birds and avoiding P release from sediment, and to decrease water residence time in the pond.

Effect and Mechanism of the Integrated Ecological Floating Bed on Eutrophic Water Treatment

A series of floating beds consisting of biounits were constructed for eutrophic water treatment in the field. Dynamic changes in water quality under each treatment were monitored to investigate treatment performance, and the mass balances of nitrogen (N) and phosphorus (P) in the integrated ecological floating bed (IEFB) were studied to reveal the interaction mechanisms operating within the beds. Water quality improvement was examined under different biounit arrangements to optimize configuration parameters. The test results showed that the concentrations of total nitrogen (TN) and total phosphorus (TP) declined linearly during the first 6 days, and the highest removal of TN (58.9%) and TP (59.1%) was observed in the IEFB, in which TN and TP removal rates reached up to 0.407 and 0.041 mg·L−1·day−1, respectively. The mass balance analysis of N/P indicated that TN was mainly removed through microbial denitrification (72.5%), with sedimentation accounting for 59.1% of TP removal. Compared with each independent biounit, the IEFB composed of multiple biounits exhibited superior performance in eutrophic water purification. The removal of N and P in the IEFB mainly depended on the bacteria and algae attached to the artificial carrier medium. Meanwhile, the aquatic animal unit enhanced the removal efficiency of TN and TP from the water by means of inorganization of particle N and P, which simultaneously improved water diaphaneity.

Agricultural nitrogen and phosphorus balances of Korea and Japan: Highest nutrient surplus among OECD member countries

Excessive nutrient balance is a very crucial issue for environmental hazards. The constant addition of high-amounts of nutrient sources in agricultural production generates negative environmental conditions in Korea and Japan yet to be resolved. Therefore, it is obligatory to comprehend the nutrient (nitrogen (N) and phosphorus (P)) balance that is assessed by the difference between nutrient input and output in the soil surface in Korea and Japan. Among 34 Economic Co-operation and Development (OECD) countries, Korea and Japan had the highest N and P balances and thus both countries are primarily responsible for severe environmental pollution via nutrient release. The cultivable land area in both countries has constantly decreased during 1990–2017 at approximately 20 and 15% in Korea and Japan, respectively. Even N and P use efficiency sharply decreased with increasing N and P balance in both targeted countries. Japanese P balance, Korean N and P balances were decreased after the mid-1990s whereas, Japanese N balance almost unchanged for the last 28 years. Unlike chemical fertilizer input, Korean manure input level significantly increased from 78 kg N ha−1 in 1990 to 157 kg N ha−1 in 2017. Japanese manure input level was higher than that of chemical fertilizer without any big change for the last 28 years. The lion share of high N and P balance in both countries could generate from manure inputs, therefore, the number of livestock and their produced debris need to be used with more cautious for the reduction of national N and P surpluses at a benchmark level. These findings ensure to make a more environment friendly policy that can further reduce nutrient balance as well as improve soil health.

Long-term effect of poultry litter application on phosphorus balances and runoff losses.

Assessment of annual and cumulative impacts of phosphorus (P) management strategies at field and watershed scales is needed to improve crop use efficiency and minimize environmental impacts. The objectives of this study were (a) to assess relationships among P balance, soil test P (STP) concentration, and runoff dissolved reactive P (DRP) concentration from fields receiving different poultry litter application rates (0.0-13.4 Mg ha-1 ) and (b) to determine the effect of long-term poultry litter application to fields on watershed DRP loss. Nutrient management practices, crop yield, STP, and runoff losses were assessed from nine fields and two watersheds located near Riesel, TX, from 2000 to 2015. Field-scale P balances were largely controlled by P application rate and exhibited a positive relationship with STP and runoff DRP flow-weighted mean concentration. Using a before-after control-impact experimental design that included monitoring at both field and watershed scales showed the influence of field P management on watershed DRP loss varied according to both source (i.e., P application rate, impacted area) and transport (i.e., hydrological connectivity) factors. Increased risk of watershed DRP loss was observed during wet years and years with two poultry litter applications to fields within the watershed. The percentage of the total watershed area receiving high rates of poultry litter also played a critical role in determining the risk of DRP loss. Findings highlight the impact of long-term P management strategies on DRP loss at both field and watershed scales and show the importance of incorporating hydrologic connectivity when assessing conservation effects on water quality.

Comparison of C:N:P Stoichiometry in the Plant–Litter–Soil System Between Poplar and Elm Plantations in the Horqin Sandy Land, China

Afforestation is among the most effective means of preventing and controlling desertification. Silver poplar (Populus alba) is commonly planted tree species for afforestation of the Horqin Sandy Land of China. However, this species has exhibited some drawbacks such as top shoot dieback, premature senescence and mortality, and soil and ecosystems degradation. In contrast, Siberian elm (Ulmus pumila) rarely experiences these problems in the same regions. Ecological stoichiometry plays a vital role in exploring ecological processes and nutrient cycle relationships in plant–litter–soil systems. To explore the differences in the carbon (C), nitrogen (N), and phosphorus (P) balance, the stoichiometry characteristics and stoichiometric homeostasis in elm and poplar plantations in the Horqin Sandy Land, we measured C, N, and P concentrations in leaves, branches, roots, litter, and soils and analyzed N and P resorption efficiencies in the two plantations. The results showed that soil C and N concentrations, C:P, and N:P were greater in the elm plantation than in the poplar plantation. The leaf and root C:P and N:P during summer and litter N and P concentrations were greater, whereas N and P resorption efficiencies were lower, in the elm plantation than in the poplar plantation. Generally, elm exhibited greater N:P homeostasis than poplar. N and N:P homeostasis were greater in roots than in leaves and branches in the elm plantation, but they varied with soil N concentration and N:P in the poplar plantation. These findings indicate that poplar exhibited more developed internal nutrient conservation and allocation strategies but poor nutrient accumulation in soil, which may contribute to degradation of poplar plantation. In contrast, elm tended to return more nutrients to the soil, showing an improved nutrient cycle in the plant–litter–soil system and increased soil C and N accumulation in the elm plantation. Therefore, compared with poplar, elm may be a more suitable afforestation tree species for the Horqin Sandy Land, in terms of promoting the accumulation of soil nutrients and enhancing nutrient cycling in the plant–litter–soil system.

An overview on deficit and requirements of the Irish national soil phosphorus balance

Phosphorus (P) is an essential life-supporting nutrient for which there is no substitute. Modern farming practice and food production are supported by the application of mineral P fertiliser derived from finite mined phosphate rock. The European Union does not have indigenous mineral phosphate reserves, which poses a significant issue to food security. This research paper assesses the potential of indigenous recycled P sources to replace imported P fertiliser within the Republic of Ireland. The research is undertaken at NUTS 3 (Nomenclature of Territorial Units) regional level, the nutrient soil P requirement is established, and the extent to which the regional production of indigenous recycled P sources can offset this requirement is determined. The soil P requirement was derived from analyzing the regional soil P indexes, stocking rate and land-use. It was established that to optimise Irish agricultural production, approximately 95,500 t of P fertiliser is required by Irish agriculture per annum. Indigenous P sources were reviewed to determine their contribution to the Irish P balance; the sources included sewage sludge, dairy processing waste, and animal manures. Regional indigenous P quantities vary greatly with the South-West Region producing the largest quantity of indigenous recycled P at 42.4% of required P than the Mid-West Region only producing 22.0% of its P requirement indigenously. Sources of indigenous P also vary greatly from region to region depending on population and industry, with the highest quantity of sewage sludge being produced in the Dublin plus Mid-East Region while the greatest contributor of dairy waste is the South-West Region. In total, over 28,500 t of P is recovered from indigenous sources per annum. This indicates that approximately 30% of the national P requirement could be met by indigenous P recycling.

Rapid Onset Development of Myocardial Calcifications in the Setting of Renal Failure and Sepsis

Myocardial calcifications can arise following damage to myocardial tissue or in the setting of disturbances in the calcium and phosphorus balance. They are associated with a number of cardiac sequelae, as well as higher mortality. Three cases of rapid-onset myocardial calcifications that developed within the course of 5 to 13 weeks in patients who had a history of sepsis and renal failure while undergoing hemodialysis are described. Baseline imaging from several weeks prior without myocardial calcification are shown for each of the three patients, demonstrating the rapid onset of these calcifications. The clinical significance of these findings is discussed. © RSNA, 2021.

The influence of enzyme probiotics on the growth, development and metabolism in young cattle

The purpose of the research was to make a comparative study of the use of enzymatic probiotics in the feeding of young cattle Black-and-White breed and to determine their effect on growth, development and metabolic processes. Under the conditions of the Amur region the use of enzymatic probiotics in the feeding of young cattle has been justified in two scientific and economic experiments. In physiological experiments the digestibility of nutrients in rations has been determined; the balance of nitrogen, calcium and phosphorus has been studied. As a result of the first scientific and economic experiment, a comparative study of the feeding of enzymatic probiotics Cellobacterin and Vitacell to calves has been carried out. It has been found that the inclusion of the enzymatic probiotic Vitacell in the rations of calves had a better effect on growth, digestibility and balance of nutrients as well as improved hematological parameters, bringing them to the physiological norms. In the second experiment the effect of the enzymatic probiotics Vitacell and Promilk on the dynamics of the live weight of young cattle, their growth, development and metabolic processes has been studied. It has been found that the enzymatic probiotic Vitacell had a better effect on growth, digestibility and nutrient balance compared to the probiotic Promilk. Thus, physiological, biochemical, zootechnical and economic research methods proved the feasibility of using probiotics in the rations of calves of Black-and-White breed, but the best results were obtained when using the probiotic Vitacell. The data of the production inspection confirmed the results obtained in scientific and economic experiments.

Nutrient Metabolism of Young Cattle in the Conditions of Yakutia When Non-Traditional Feed Additives are Included in Their Rations

The work is aimed to develop innovative ways to increase effectiveness of a process of acclimatization and adaptation of the Hereford breed youngsters of Siberian selection, to increase its beef productivity, to enhance its usage of nutrient materials in the diet through inclusion to the diet of animals the local mineral feed supplements (Hongurin’s zeolite and putrid mud) with mineral salt that compensate a deficit of mineral materials in the diet. The number of hemoglobin was larger in the experimental groups of animals than in the control group of bull-calves, which demonstrates better metabolic processes. Balance of nitrogen, calcium, and phosphorus in every studied group was positive. High rates of the usage of nitrogen, calcium, and phosphorus, from taken to digested, were in the first and the second experimental groups of bull-calves. The usage of the local mineral feed supplements in the Hereford breed bull-calves’ diet provided increasing in their digestibility of nutrient materials, such as, in average, crude protein by 2,63 and 2,78%, crude fat by 2,32 and 3,24%, crude fiber by 1,77 and 3,27%, nitrogen-free extractable substances by 5,12 and 8,40%. Higher indicators of fixed nitrogen, calcium, and phosphorus from taken to digested were in the first and the second experimental groups of bull-calves. Results of the experiment established relevance and effectiveness of the inclusion in the diet the local mineral feed supplements for the Hereford breed bull-calves.

Effects of phosphorus application rates on spring rape yield and soil phosphorus balance.

Excessive application of phosphorus fertilizer leads to high soil available phosphorus content but low phosphorus use efficiency in the main production areas of spring rape in eastern Qinghai. Understanding the effects of phosphorous application rates on the growth, phosphorus absorption, soil phosphorus balance in the field of spring rape could improve nutrient management of spring rape, and benefit for the sustainable development of agriculture in Qinghai-Tibet Plateau. A field experiment was carried out in Huzhu County of Qinghai Province from 2017 to 2018. We mea-sured seed yield, phosphorus uptake and oil content of spring rape under five phosphorous fertilizer rates (0, 30, 60, 90 and 120 kg P2O5·hm-2). In 2017, the seed yield and oil production of spring rape with the rate of 60 kg·hm-2 were significantly higher than that of no phosphorus fertilizer treatment. In contrast, seed yield and oil production did not increase when the phosphorus rate exceeded 60 kg·hm-2 in 2017. Phosphorus rate did not affect seed yield, phosphorus accumulation, and oil production of spring rape in 2018. The phosphorus use efficiency was low in both years, with a mean value of 6.7%. Phosphorus fertilizer application caused phosphorus surplus in soils, which was low when the application rate was less than 60 kg·hm-2. Our results suggest that the rate of 60 kg·hm-2 is suitable for spring rape production in the eastern Qinghai Province.

Nutrients balance under organic rice farming system in Central Java, Indonesia

Understanding and calculation the net nutrient balance in an organic rice farming system is crucial to determine its ability to maintain soil fertility in the long term. The objective of this study is to calculate simple nutrient balances of nitrogen (N), phosphorus (P), and potassium (K) under different sources of organic fertilizer in organic rice farming. The results indicated an imbalance between nutrients, a general surplus for P budget +0.8 to +43.5 kg ha−1 season−1 and deficit for N budgets from -49.2 to +38.5 kg ha−1 season−1; and K -56.8 to +38.6 kg ha−1 season−1. The application of 5t ha−1 of chicken manure combined with 500 kg ha−1 of azolla and 2 t ha−1 of straw compost gave better growth, yield and positive N, P, K balance for local rice variety Mentik Wangi.

Effects of Infusing and Feeding Antibiotic on Growth and Nutrient Balance in Sheep

TWO growth trials and nutrient digestibility studies were done using 12 Hampshire Rambouillet crossbred lambs given antibiotic orally or abomasally. Daily gain and efficiency of feed utilization were lower in the abomasally-infused animals. Crude fibre, protein, dry and organic matter digestibility was significantly lower [P<0.05] in those on oral antibiotics, as was the statistically significant difference in phosphorus intake [P<0.05). A 2-way analysis of variance showed that antibiotic administered orally or intra-abomasally did not significantly effect any changes in serum calcium and phosphorus balance. The average daily gain obtained in the second growth trial when the abomasally-infused group was switched on to oral antibiotic was the same as those on oral antibiotic from the start. These data indicate that oral route of antibiotic administration is preferable.

БАЛАНС ЭЛЕМЕНТОВ ПИТАНИЯ В СЕВООБОРОТАХ В УСЛОВИЯХ БИОЛОГИЗИРОВАННОГО АДАПТИВНО-ЛАНДШАФТНОГО ЗЕМЛЕДЕЛИЯ

In the light of recent developments, the use of biological techniques in crop cultivation technologies needs to be expanded. The role of crop rotations with a high proportion of legume grasses, green manure crops and intermediate crops is increasing. The purpose of the research is to study soil fertility dynamics in terms of the main nutritional elements and determine their balance for the development of the adaptive landscape farming system in the North-Eastern region of the European part of Russia. Experiments were carried out on the experimental plots of the FARC of the North-East in 2002–2009. Soil – sod-podzolic middle loamy. We analyzed data of a long-term stationary experiment in four grain-fallow-grass field crop rotations. Meteorological conditions during the years of research were close to the average long-term values and favorable for crop cultivation. The introduction of low doses of fertilizers (N45P45K45 as mineral, 11.5–22.5 t/ha as green manure) increased the content of mobile phosphorus in the soil by 11–14 mg/kg (LSD05 = 9.5) in crop rotations with occupied and green manure fallows. An increase in exchangeable potassium by 15 mg/kg (LSD05 = 14.1) was noted in crop rotation with two clover fields for green manure. A positive balance of nitrogen and phosphorus was obtained in crop rotation with occupied and green manure fallows. The nitrogen balance was with a higher intake of +157.8 – +483.5 kg/ha and balance intensity – 115–140 %. The balance of phosphorus has developed at +6.0…+49.6 kg/ha. The positive balance of potassium was only in crop rotations with the introduction of green manure fertilizers and intermediate crop (+69.9…+175.8 kg/ha). The intensity of the balance of these elements was 101–118 %. In the control crop rotation with bare fallow at a minimum intake of nutrients, the negative balance of nitrogen, phosphorus and potassium was obtained; the intensity was below 100 %. Productivity of crop rotation was at the level of 4.90–5.41 thousand fodder units. According to the optimal combination of productivity and the balance of nutritional elements, crop rotation with two clover fields for green manure and an intermediate crop stood out.