Effects of three types of soil amendments on yield and soil nitrogen balance of maize–wheat rotation system in the Hetao Irrigation Area, China

Excessive fertilization combined with unreasonable irrigation in farmland of the Hetao Irrigation Area(HIR), China, has resulted in a large amount of nitrogen(N) losses and agricultural non-point source pollution.Application of soil amendments has become one of the important strategies for reducing N losses of farmland.However, there is still no systematic study on the effects of various soil amendments on N losses in the HIR.In this study, three types of soil amendments(biochar, bentonite and polyacrylamide) were applied in a maize–wheat rotation system in the HIR during 2015–2017.Yields of maize and wheat, soil NH3 volatilization, N2O emission and NO3– leaching were determined and soil N balance was estimated.The results showed that applications of biochar, bentonite and polyacrylamide significantly increased yields of maize by 9.2%, 14.3% and 13.3%, respectively, and wheat by 9.2%, 16.6% and 12.3%, respectively, compared with the control(fertilization alone).Applications of biochar, bentonite and polyacrylamide significantly reduced soil N leaching by 23.1%, 35.5% and 27.1%, soil NH3-N volatilization by 34.8%, 52.7% and 37.8%, and soil N surplus by 23.9%, 37.4% and 30.6%, respectively.Applications of bentonite and polyacrylamide significantly reduced N2O-N emissions from soil by 37.3% and 35.8%, respectively, compared with the control.Compared with application of biochar, applications of bentonite and polyacrylamide increased yields of maize and wheat by 5.1% and 3.5%, respectively.Our results suggest that soil amendments(bentonite and polyacrylamide) can play important roles in reducing N losses and increasing yield for the maize–wheat rotation system in the HIR, China.

Diversity Analysis of Chlorophyll, Flavonoid, Anthocyanin, and Nitrogen Balance Index of Tea Based on Dualex

The chemical compositions of tea(Camellia sinensis)are affected by numerous factors,such as cultivar,climate,leaf position,and cultivation pattern.However,under the same conditions,the chemical compositions are mainly determined by varieties.Therefore,we investigated the genetic diversity of chemical compositions of tea tree resources in China to screen excellent germplasm resources.Three chemical compositions index(including chlorophyll index,flavonoid index,and anthocyanin index)and the nitrogen balance index of tea leaves were measured in 102 tea germplasms planted in Chinese Tea Plants Improved Variety Germplasm Resources Nursery(CTPIVGRN)by Dualex on April 152019.Results showed that the chlorophyll,flavonoid,and anthocyanin contents and the nitrogen balance index significantly differed between the 102 tea germplasms.The genetic diversity index values were 2.005,2.246,1.599,and 1.838,and the average genetic diversity was 1.922.The 102 tea germplasms can be divided into four categories by cluster analysis under the genetic distance threshold of 11.These results suggest that the genetic diversity of tea germplasm resources in China is rich.This study’s results can serve as a basis for the diversified development and utilization of tea plant.

Protein Requirements in Healthy Adults: A Meta-analysis of Nitrogen Balance Studies

Objective The goal of this study was to analyze protein requirements in healthy adults through a meta-analysis of nitrogen balance studies. Methods A comprehensive search for nitrogen balance studies of healthy adults published up to October 2012 was performed, each study were reviewed, and data were abstracted. The studies were first evaluated for heterogeneity. The average protein requirements were analyzed by using the individual data of each included studies. Study site climate, age, sex, and dietary protein source were compared. Results Data for 348 subjects were gathered from 28 nitrogen balance studies. The natural logarithm of requirement for 348 individuals had a normal distribution with a mean of 4.66. The estimated average requirement was the exponentiation of the mean of the log requirement, 105.64 mg N/kg·d. No significant differences between adult age, source of dietary protein were observed. But there was significant difference between sex and the climate of the study site （P〈0.05）. Conclusion The estimated average requirement and recommended nutrient intake of the healthy adult population was 105.64 mg N/kg·d （0.66 g high quality protein/kg·d） and 132.05 mg N/kg·d （0.83 g high quality protein/kg·d）, respectively.

Effects of Supplemental Carbohydrate Sources on Lactation Performance, Nitrogen Balance,and Ruminal Fermentation in Dairy Cows Fed Energy-Deficient Total Mixed Rations

The effects of supplemental carbohydrate （CHO） sources on milk yield and composition, nitrogen （N） balance,and ruminal fermentation were evaluated in lactating dairy cows fed energy-deficient total mixed rations （TMR） . Fifty-six lactating Holstein cows （36. 8 ± 3. 4 kg / d of milk yield; 152 ± 26 days in milk [DIM]） were randomly assigned to one of four diets： （1） basal TMR （control） ; （2） basal TMR ＋ 1. 25 kg / d sucrose （SUC） ; （3） basal TMR ＋ 2. 12 kg /d steam-flaked corn （SFC） ; （4） basal TMR ＋ 2. 23 kg / d wheat （WHE） . The trial lasted 70 days,including the first 10 days of adaptation. Simultaneously, a 4 × 4 Latin square trial was conducted with four ruminally cannulated cows of similar DMI （Dry Matter Intake） fed on the above four diets. Each testing period lasted 18 days： 15 days for adaptation and 3 days for sampling. Cows fed SUC-,SFC-,and WHE-supplemented diets produced 1. 6,2. 9,and 0. 8 kg / d,respectively,more milk than those on the basal TMR control diet,but the difference was not significant （P = 0. 160） . However,the production of energy-corrected milk of cows fed CHO-supplemented diets improved significantly （P = 0. 020） ,and the yield of 4% fatcorrected milk tended to be higher （P = 0. 063） than in control animals. Percentages of milk protein,lactoseand solids-not-fat （SNF） increased significantly in cows fed CHO-supplemented diets （P 〈 0. 05） ,and yields of milk protein and SNF were significantly higher （P 〈0. 05） ; yields of milk fat and lactose were somewhat higher （P 〈 0. 10） . Cows receiving supplementary CHO diets consumed more DM （Dry Matter） （P = 0. 023） ; however,there was no significant difference in N retention,digestibility,or utilization efficiency among the treatments （P 〉 0. 10） . The average ruminal pH was lowest in cows supplemented with SUC,while that in cows supplemented with SFC and WHE was only slightly reduced （P = 0. 025） . Ruminal NH 3 -N concentration was highest with no supplementary CHO （P = 0. 017） ,and changes in postfeeding time were similar across the diets. Total volatile fatty acid concentration was significantly lower in control animals than in those on SUCand WHE-supplemented diets （P = 0. 001） ; significant dietary responses were observed in the concentrations of acetate,butyrate,and branchedchain fatty acids and in the acetate-to-propionate ratio （P 〈0. 001） . These results indicate that supplementation with different CHO sources in energy-deficient diets substantially improved the balance of energy and N in the rumen,altered ruminal fermentation,and improved lactation performance in dairy cows.

Metabolizable energy,nitrogen balance,and ileal digestibility of amino acids in quality protein maize for pigs

Background：To compare the nutritional value and digestibility of five quality protein maize（QPM） hybrids to that of white and yellow maize,two experiments were carried out in growing pigs.In experiment 1,the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize.In experiment 2,the apparent and standardized ileal digestibility（AID and SID,respectively） of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize.In both experiments,the comparisons were conducted using contrasts.Results：The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids（P 〈 0.05） than in the pigs fed white or yellow maize.Energy digestibility（P 〈 0.001） and metabolizability（P 〈 0.01） were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets.The AID of lysine was higher（P〈 0.01） in the QPM diets than in the white and yellow maize.The AIDs of leucine,isoleucine,valine,phenylalanine,and methionine were lower in the QPM diets than those of maize（white and yellow）（all P 〈 0.05）.Maize（white and yellow） had greater SIDs of leucine,isoleucine,valine,phenylalanine,glutamic acid,serine,alanine,tyrosine,and proline（P 〈 0.05）.Conclusions：Based on these results,it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize.

Postponed and reduced basal nitrogen application improves nitrogen use efficiency and plant growth of winter wheat

Excessive nitrogen(N) fertilization with a high basal N ratio in wheat can result in lower N use efficiency(NUE) and has led to environmental problems in the Yangtze River Basin, China. However, wheat requires less N fertilizer at seedling growth stage, and its basal N fertilizer utilization efficiency is relatively low; therefore, reducing the N application rate at the seedling stage and postponing the N fertilization period may be effective for reducing N application and increasing wheat yield and NUE. A 4-year field experiment was conducted with two cultivars under four N rates(240 kg N ha–1(N240), 180 kg N ha–1(N180), 150 kg N ha–1(N150), and 0 kg N ha–1(N0)) and three basal N application stages(seeding(L0), fourleaf stage(L4), and six-leaf stage(L6)) to investigate the effects of reducing the basal N application rate and postponing the basal N fertilization period on grain yield, NUE, and N balance in a soil-wheat system. There was no significant difference in grain yield between the N180 L4 and N240 L0(control) treatments, and the maximum N recovery efficiency and N agronomy efficiency were observed in the N180 L4 treatment. Grain yield and NUE were the highest in the L4 treatment. The leaf area index, flag leaf photosynthesis rate, flag leaf nitrate reductase and glutamine synthase activities, dry matter accumulation, and N uptake post-jointing under N180 L4 did not differ significantly from those under N240 L0. Reduced N application decreased the inorganic N content in the 0–60-cm soil layer, and the inorganic N content of the L6 treatment was higher than those of the L0 and L4 treatments at the same N level. Surplus N was low under the reduced N rates and delayed basal N application treatments. Therefore, postponing and reducing basal N fertilization could maintain a high yield and improve NUE by improving the photosynthetic production capacity, promoting N uptake and assimilation, and reducing surplus N in soil-wheat systems.

Nitrogen Use Efficiency as Affected by Phosphorus and Potassium in Long-Term Rice and Wheat Experiments

Improving nitrogen use efficiency （NUE） and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N agronomic efficiency （NAE） and N loss in long-term （16- or 24-yr） experiments carried out at three rice-wheat rotation sites （Chongqing, Suining and Wuchang） in subtropical China. Three treatments were examined： sole chemical N, N＋phosphorus （NP）, and NP＋potassium （NPK） fertilizations. Grain yields at three sites were significantly increased by 9.3-81.6% （rice） and 54.5-93.8% （wheat） under NP compared with N alone, 1.7-9.8% （rice） and 0-17.6% （wheat） with NPK compared with NP. Compared to NP, NUE significantly increased for wheat at Chongqing （9.3%） and Wuchang （11.8%）, but not at Suining, China. No changes in NUE were observed in rice between NP and NPK at all three sites. The rice-wheat rotation＇s NAE was 3.3 kg kg1 higher under NPK than under NP at Chongqing, while NAE was similar for NP and NPK at Suining and Wuchang. We estimated that an uptake increase of 1.0 kg N hal would increase 40 kg rice and 30 kg wheat ha-1. Nitrogen loss/input ratios were -60, -40 or -30% under N, NP or NPK at three sites, indicating significant decrease of N loss by P or PK additions. We attribute part of the increase in NUE soil N accumulation which significantly increased by 25-55 kg ha-1 yr1 under NPK at three sites, whereas by 35 kg ha-1 yr-1 under NP at Chongqing only. This paper illustrates that apply P and K to wheat, and reduce K application to rice is an effective nutrient management strategy for both the NUE improvement and N losses reduction in China.

Comparative Study on Nitrogen Metabolism and the Nitrogen Maintenance Requirement in Lohmann Brown Roosters and Layers

The objective of this study was to in- vestigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohm- ann Brown adult roosters and layers. The nitrogen ma- intenance requirement （Nm ） was determined based on the nitrogen balance. Thirty Lohmann Brown adult roosters and 30 laying hens at 27 weeks of age were randomly divided into five groups of six birds per group. The birds were fed with one of five diets con- taining 10.46%, 11.77%, 13.79%, 16.77% or 18.29% of crude protein. Nitrogen intake, nitrogen retention and nitrogen retention efficiency were higher in roost- ers than in laying hens, and the average nitrogen re- tention rate for groups fed with CP level of 11.77%, 13.79%, 16.77% and 18. 29% was improved by9.14%. The nitrogen maintenance requirement for Lohmann Brown roosters and laying hens at 27 weeks of age were 0.4245 g/d and 0.5059 g/d, respective- ly, and Nm based on average body weight （BW） and metabolic body weight （ BW^Ts ） was 0.2364 g/kg BW and 0. 2739 g/kg BW~＇75 for laying hens and 0. 2754 g/kg BW and 0. 3208 g/kg BW^72 for roost- ers, respectively. The regression equations for daily N gain （NB, protein accretion） vs. daily N intake （NI ） for Lohrnann Brown layers and roosters were NB = 0.3743NI -0.1589（R2 =0.79） and NB =0.6228NI - 0.3151 （ R2 = 0.85 ）, respectively. The results of this study indicate that nitrogen intake and nitrogen reten- tion at the same dietary CP level were higher in roost- ers than in laying hens.

Integrated application of February Orchid(Orychophragmus violaceus) as green manure with chemical fertilizer for improving grain yield and reducing nitrogen losses in spring maize system in northern China

The development of more efficient management systems is crucial to achieving high grain yields with high nitrogen use efficiency（NUE）. February Orchid-spring maize rotation system is a newly established planting system with the benefits of ground cover and potential wind erosion in northern China. A field experiment was conducted to evaluate the effects of integrated application of February Orchid as green manure with reduction of chemical fertilizers（INTEGRATED） on spring maize yield, N uptake, ammonium volatilization, and soil residual mineral N in northern China. Compared to farmers＇ traditional fertilization（CON）, integrated application of February Orchid as green manure with 30% reduction of nitrogen fertilizers（INTEGRATED） increased maize grain yield and biomass by 9.9 and 10.2%, respectively. The 0–100 cm soil residual Nmin at harvest was decreased by 58.5% and thus nitrogen use efficiency was increased significantly by 26.7%. The nitrogen balance calculation further demonstrated that the INTEGRATED approach performed better than CON with lower apparent nitrogen loss（decreased by 48.9%） which evidenced by the ammonium volatilization of top-dressing fertilizer was decreased by 31.1%, the N_（min） movement to the deeper soil layers was reduced, and the apparent nitrogen leaching loss nearly equal to 0 under the INTEGRATED treatment. Therefore, in northern China, integrated application of green manure and chemical fertilizers is an efficient management approach for improving maize yields and NUE simultaneously.

Nitrogen mobility,ammonia volatilization,and estimated leaching loss from long-term manure incorporation in red soil

Nitrogen（N） loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practices. The aim of this study was to evaluate the fate of N fertilizers applied to acidic red soil（Ferralic Cambisol） after 19 years of mineral（synthetic） and manure fertilizer treatments under a cropping system with wheat-maize rotations. Five field treatments were examined： control（CK）, chemical nitrogen and potash fertilizer（NK）, chemical nitrogen and phosphorus fertilizer（NP）, chemical nitrogen, phosphorus and potash fertilizer（NPK） and the NPK with manure（NPKM, 70% N from manure）. Based on the soil total N storage change in 0–100 cm depth, ammonia（NH_3） volatilization, nitrous oxide（N_2O） emission, N plant uptake, and the potential N leaching loss were estimated using a mass balance approach. In contrast to the NPKM, all mineral fertilizer treatments（NK, NP and NPK） showed increased nitrate（NO_3~–） concentration with increasing soil depth, indicating higher leaching potential. However, total NH_3 volatilization loss was much higher in the NPKM（19.7%） than other mineral fertilizer treatments（≤4.2%）. The N_2O emissions were generally low（0.2–0.9%, the highest from the NPKM）. Total gaseous loss accounted for 1.7, 3.3, 5.1, and 21.9% for NK, NP, NPK, and NPKM treatments, respectively. Estimated N leaching loss from the NPKM was only about 5% of the losses from mineral fertilizer treatments. All data demonstrated that manure incorporation improved soil productivity, increased yield, and reduced potential leaching, but with significantly higher NH_3 volatilization, which could be reduced by improving the application method. This study confirms that manure incorporationis an essential strategy in N fertilization management in upland red soil cropping system.

Intake,digestibility and nitrogen utilization in cattle fed tropical forage and supplemented with protein in the rumen,abomasum,or both

Background： There is little information in the tropics with regard the comparative understanding of how an increased nitrogen supply in the rumen or in the intestines affects efficiency of nitrogen utilization in cattle. This study evaluated the effects of supplementation with nitrogenous compounds in the rumen, abomasum, or both on intake, digestibility and the characteristics of nitrogen utilization in cattle fed tropical forage. Four rumen- and abomasum-fistulated Nellore bulls （227 ± 11 kg） were used. Four treatments were evaluated： control, ruminal supplementation （230 g/d of supplemental protein in the rumen）, abomasal supplementation （230 g/d of supplemental protein in the abomasum）, and ruminal and abomasal supplementation （115 g/d protein in both the rumen and the abomasum）. The basal forage diet consisted of Tifton 85 hay with a crude protein （CP） level of 78.4 g/kg dry matter. Casein was used as a supplement. The experiment was conducted using a 4 x 4 Latin square. Results： There were no differences between the treatments （P 〉 0.10） with regard to forage intake. The intake and tota digestibility of CP increased （P 〈 0.01） with supplementation. The nitrogen balance in the body increased （P 〈 0.01） and muscle protein mobilization decreased （P 〈 0.01） with supplementation, regardless of the supplementation site. The efficiency of nitrogen utilization did not differ among the treatments （P 〉 0.10）. Conclusions： The supplementation of cattle fed tropical forage with protein in the rumen, abomasum, or both similarly increased the nitrogen accretion in animal, which reflects improvements on nitrogen status in animal body.

Energy and protein requirements for maintenance of Hu sheep during pregnancy

This study aimed to determine the effect of stage and level of feed intake on energy metabolism, carbon-nitrogen （C-N） balance, and methane emission to determine energy and protein requirements for maintenance of maternal body including pregnancy tissues during pregnancy using the method of C-N balance. Twenty-one ewes carrying twin fetuses were randomly divided into three groups of seven ewes each in the digestion and respirometry trial at d 40, 100, and 130 of gestation, respectively. Three groups were fed a mixed diet either for ad lib#urn intake, 70 or 50% of the ad libfum intake during pregnancy. The results showed that the apparent digestibility of C and N were increased as feeding levels decreased at each stage of gestation. The daily net energy requirements for maintenance （NEro） were 295.80, 310.09, and 323.59 kJ kg-1 BW0.75 （metabolic body weight） with a partial efficiency of metabolisable energy utilization for maintenance of 0.664, 0.644, and 0.620 at d 40, 100, and 130 of gestation, respectively. The daily net protein requirements for maintenance were 1.99, 2.35, and 2.99 g kg-1 BW0.75 at d 40, 100, and 130 of gestation, respectively. These results for the nutritional requirements of the net energy and protein may help to formulate more balanced diets for Hu sheep during pregnancy.

Industrial application prospects and key issues of the pure-hydrogen reduction process

The industrial application prospect and key issues in basic theory and application are discussed by the methods of theoretical analysis and calculation to promote the development of the pure-hydrogen reduction process.According to the discussion of thermodynamics and kinetics of pure-hydrogen reduction reaction,the reduction reaction of iron oxide by pure hydrogen is an endothermic reaction,and the reaction rate of hydrogen reduction is significantly faster than that of carbon reduction.To explore the feasibility of the industrial applications of pure-hydrogen reduction,we design the hydrogen reduction reactor and process with reference to the industrialized hydrogen-rich reduction process and put forward the methods of appropriately increasing the reduction temperature,pressure,and temperature of iron ore into the furnace to accelerate the reaction rate and promote the reduction of iron oxide.The key technical parameters in engineering applications,such as hydrogen consumption,circulating gas volume,and heat balance,are discussed by theoretical calculations,and the optimized parameter values are proposed.The process parameters,cost,advantages,and disadvantages of various current hydrogen production methods are compared,and the results show that hydrogen production by natural gas reforming has a good development prospect.Through the discussion of the corrosion mechanism of high-temperature and high-pressure hydrogen on heat-resistant steel materials and the corrosion mechanism of H_2S in the hydrogen gas on steel,the technical ideas of developing new metal temperature-resistant materials,metal coating materials,and controlling gas composition are put forward to provide guidance for the selection of heater and reactor materials.Finally,the key factors affecting the smooth operation of the hydrogen reduction process in engineering applications are analyzed,offering a reference for the industrial application of the purehydrogen reduction process.

Lipopolysaccharide immune stimulation but not β-mannanase supplementation affects maintenance energy requirements in young weaned pigs

Background: Pathogen or diet-induced immune activation can partition energy and nutrients away from growth,but clear relationships between immune responses and the direction and magnitude of energy partitioning responses have yet to be elucidated. The objectives were to determine how β-mannanase supplementation and lipopolysaccharide(LPS) immune stimulation affect maintenance energy requirements(MEm) and to characterize immune parameters, digestibility, growth performance, and energy balance.Methods: In a randomized complete block design, 30 young weaned pigs were assigned to either the control treatment(CON; basal corn, soybean meal and soybean hul s diet), the enzyme treatment(ENZ; basal diet + 0.056% β-mannanase),or the immune system stimulation treatment(ISS; basal diet + 0.056% β-mannanase, chal enged with repeated increasing doses of Escherichia coli LPS). The experiment consisted of a 10-d adaptation period, 5-d digestibility and nitrogen balance measurement, 22 h of heat production(HP) measurements, and 12 h of fasting HP measurements in indirect calorimetry chambers. The immune chal enge consisted of 4 injections of either LPS(ISS) or sterile saline(CON and ENZ), one every48 h beginning on d 10. Blood was collected pre-and post-challenge for complete blood counts with differential,haptoglobin and mannan binding lectin, 12 cytokines, and glucose and insulin concentrations.Results: Beta-mannanase supplementation did not affect immune status, nutrient digestibility, growth performance,energy balance, or MEm. The ISS treatment induced fever, elevated proinflammatory cytokines and decreased leukocyte concentrations(P < 0.05). The ISS treatment did not impact nitrogen balance or nutrient digestibility(P > 0.10),but increased total HP(21%) and MEm(23%), resulting in decreased lipid deposition(-30%) and average daily gain(-18%)(P < 0.05).Conclusions: This experiment provides novel data on β-mannanase supplementation effects on immune parameters and energy balance in pigs and is the first to directly relate decreased ADG to increased MEm independent of changes in feed intake in immune challenged pigs. Immune stimulation increased energy partitioning to the immune system by 23% which limited lipid deposition and weight gain. Understanding energy and nutrient partitioning in immune-stressed pigs may provide insight into more effective feeding and management strategies.

Nitrogen mass balance in a constructed wetland treating piggery wastewater effluent

The nitrogen changes and the nitrogen mass balance in a free water surface flow constructed wetland （CW） using the four-year monitoring data from 2008 to 2012 were estimated. The CW was composed of six cells in series that include the first settling basin （Cell 1）, aeration pond （Cell 2）, deep marsh （Cell 3）, shallow marsh （Cell 4）, deep marsh （Cell 5） and final settling basin （Cell 6）. Analysis revealed that the NH4＋-N concentration decreased because of ammonification which was then followed by nitrification. The NO4＋-N and NO4＋-N were also further reduced by means of microbial activities and plant uptake during photosynthesis. The average nitrogen concentration at the influent was 37,819 kg/year and approximately 45% of that amount exited the CW in the effluent. The denitrification amounted to 34% of the net nitrogen input, whereas the accretion of sediment was only 7%. The biomass uptake of plants was able to retain only 1% of total nitrogen load. In order to improve the nutrient removal by plant uptake, plant coverage in four cells （i.e., Cells 1, 3, 4 and 5） could be increased.

Clinical Comparative Study of Parenteral Nutritionvia Portal Vein or via Peripheral Vein

The purpose of this study was to evaluate the metabolic effects of parenteral nutrition(PN) via portal vein or peripheral vein. Fourteen patients undergone operations for colorectal cancer were divided into two groups randomly. Seven patients had portal venous catheter inserted during the operation. The nutrition support was started on the second postoperative day and continued for consecutive 5 days. The PN was given as a mixture which provided 6.2 gN/d and 5607 kJ/d of nonprotein energy with carbohydrate/fat energy ratio of 62%:38%. The mixture was infused via portal vein in seven cases(PV group) and via peripheral vein in the other seven cases as control (CTR group). Nitrogen balance was monitored and plasma albumin, triglyceride, cholesterol, bilirubin, alanine transaminase, and blood sugar were measured before and after PN in both groups, and no significant difference was found between the two groups. However, by the end of PN cumulative nitrogen balance in the PV group and CTR group was -0.53±2.30 gN/5d and -5.39±2.8 gN/5d (P<0.05), respectively. An increased serum potassium level was observed after fivedays PN in CTR group. The results suggest that PN via portal vein provides a beneficial effect on maintaining nitrogen balance in postoperative patients.

Soil mineral nitrogen dynamics in fallow periods in a rainfed semiarid Mediterranean agricultural system

Rainfed agricultural systems in semiarid Mediterranean environments are subject to erratic but often heavy rainfall events.As an agronomic practice,fallow periods can be included even within the existing European Union common policy for crop diversification.This study aimed to quantify the effects of previous mineral fertilization on soil mineral nitrogen(N_(min))content and potential nitrate leaching during no-till fallow periods of crop rotation.The Leaching Estimation and Chemistry Model(LEACHM)was used for soil N_(min)prediction after fallow.During fallow periods,N_(min)measured in the soil profile increased by an average of 125 kg N ha^(-1),whereas the model showed an average increase of 95 kg N ha^(-1).The amount of nitrogen(N)leached was estimated to be 11–38 kg N ha^(-1).The N balance simulated using LEACHM might differ from the actual situation.The calibrated LEACHM underestimated soil N_(min)after a drought period followed by soil water replenishment,probably due to a pulse in soil C and N mineralization caused by the wetting of dry soil,but overestimated soil N_(min)after occasional rainy spells when soil quickly became saturated,probably due to occasional nitrous oxide emissions not being fully accounted for by the model and specific preferential water flow,which might lead to greater nitrate leaching than that simulated by LEACHM using the convection-dispersion equation.The results show that soil N_(min)measurements after fallow periods cannot be well predicted by LEACHM.The findings of this study provide a support for fertilization planning for crop rotation systems including a fallow period to avoid overfertilization in the following cropping season and reduce N environmental impacts.

Numerical study of regional environmental carrying capacity for livestock and poultry farming based on planting-breeding balance

In consideration of the need to maintain planting-breeding balance, this article examines the capacity of the soil in Putian City, Fujian Province to absorb livestock and poultry excreta, and computes the environmental carrying capacity for livestock and poultry farming （ECCLPF） in each district of the city in terms of the fertility characteristics of the soil in the city, as well as its mix of crops cultivated and farming methods. On the basis of the computations, this work proceeds to classify the alarm grades of the city＇s environmental carrying capacity for livestock and poultry framing, and assess the environmental impact of the livestock and poultry farming industry. The results of our study indicate that, the city＇s ECCLPF ranges from 8.27 to 23.23 heads per ha when computed on the basis of nitrogen, and from 5.79 to 24.53 heads per ha when computed on the basis of phosphorus. A comparison between our research findings and the existing farming scale in Putian reveals that, in certain parts of the city, ECCLPF is overburdened to varying degrees. Specifically, Chengxiang District is severely overburdened, Hanjiang District and Meizhou Island have a level of overburdening between virtual overburdening and significant overburdening, Licheng District is virtually overburdened, and Xiuyu, Xianyou, and Bei＇an Districts have not exceeded their environmental carrying capacity and therefore have varying levels of potential for growth.

Characterization of Bacillus subtilis Ab03 for efficient ammonia nitrogen removal

An efficient ammonia nitrogen degrading bacterial strain was isolated from a fish and shrimp pond and identified as Bacillus subtilis(Ab03).Firstly,the strain was continuously domesticated in ammonium solution to improve its nitrogen removal capacity.The performance of the strain in terms of nitrogen removal efficiency under different culture conditions was then examined.Finally,the nitrogen removal process and related strain mechanisms were analyzed by nitrogen balance.The results showed the strain Ab03 could remove 91.67% of NH_(4)^(+)-N at 300 mg/L under the conditions of glucose as the single carbon source,C/N of 15,pH of 7.5,the temperature of 35℃ and dissolved oxygen of 7-8 mg/L.It was also found that under conditions where ammonia nitrogen was the only nitrogen source,strain Ab03 could also undergo aerobic denitrification for simultaneous conversion,with a final gas conversion rate of 74.81%.