The AA profile of MP affects mammary gland metabolism and milk N efficiency of dairy cattle. Further, the frequency of dietary protein supplementation may influence N partitioning leading to reduced ...N excretion. This study investigated the effect of source and frequency of rumen-protected (RP) protein supplementation on apparent total-tract digestibility, milk production, mammary gland AA metabolism, and N balance of dairy cattle. Twenty-eight Holstein-Friesian cows (2.3 ± 0.9 lactations; 93 ± 27 d in milk; mean ± SD) were used in a randomized complete block design and fed a basal total mixed ration (TMR) consisting of 41% corn silage, 32% grass silage, and 27% concentrate (DM basis) and formulated to meet 100 and 95% of net energy and MP requirements, respectively. Cows were adapted to the basal TMR in a free stall barn for 7 d, moved to individual tie stalls for 13 d of adaptation to dietary treatments, and then moved into climate respiration chambers for a 4-d measurement period. Treatments consisted of the basal TMR (CON; 159 g CP/kg DM) or the basal TMR including 1 of 3 iso-MP supplements: 1) 315-g mixture of RP soybean meal and RP rapeseed meal fed daily (ST-RPSR), 2) 384-g mixture of RP His, RP Lys, and RP Met fed daily (ST-RPAA), and 3) 768-g mixture of RP His, RP Lys, and RP Met fed every-other day (OS-RPAA). The basal TMR with the addition of treatment supplements was designed to deliver 100% of required MP over a 48-h period. The mixture of His, Lys, and Met was formulated to deliver digestible AA in amounts relative to their concentration in casein. Compared with ST-RPSR, ST-RPAA increased milk protein and fat concentration, increased the arterial concentration of total His, Lys, and Met (HLM), decreased mammary clearance of HLM, and increased clearance of Phe, Leu and Tyr (tendency for Leu and Tyr). Rumen-protected protein source did not affect N balance, but the marginal use efficiency (efficiency of transfer of RP protein supplement into milk protein) of ST-RPAA (67%) was higher than that of ST-RPSR (17%). Milk protein concentration decreased with OS-RPAA compared with ST-RPAA. Arterial concentration of HLM increased on the non-supplemented day compared with the supplemented day with OS-RPAA, and there was no difference in arterial HLM concentration across days with ST-RPAA. Mammary uptake of HLM tended to increase on the non-supplemented day compared with the supplemented day with OS-RPAA. Supplementation frequency of RP AA did not affect N balance or overall milk N efficiency, but the marginal use efficiency of OS-RPAA (49%) was lower compared with ST-RPAA. Overall, mammary glands responded to an increased supply of His, Lys, and Met by reducing efflux of other EAA when RP His, RP Lys, and RP Met were supplemented compared with RP plant proteins. Mammary glands increased sequestration of EAA (primarily HLM) on the non-supplemented day with OS-RPAA, but supplementing RP AA according to a 24-h oscillating pattern did not increase N efficiency over static supplementation.
•Straw return treatments were more likely to improve soil structure, not only in topsoil layers but also in subsoil layers, especially at plough pan.•Nitrogen deficiency moderately significantly ...induced larger root length density of subsoil and its proportion.•The level of significance between soil bulk density of 20–40 cm soil layer and root length density in 0–120 cm soil layer reached a very significant level.•Suitable amount of straw returned back to field, combining with nitrogen deficiency moderately, achieved higher nitrogen efficiency dramatically, on the basis of sacrificing grain yield slightly.
Grain yields of winter wheat are significantly affected by different straw and nitrogen regimes through regulating root growth and distribution in soil, especially in subsoil layers. In this study, three straw regimes used were S0 (no straw return), S1 (4500 kg ha−1 of maize straw returned), S2 (9000 kg ha−1 of maize straw returned) and four nitrogen regimes used were N0 (no nitrogen applied), N1 (150 kg ha−1 nitrogen applied), N2 (225 kg ha−1 nitrogen applied) and N3 (300 kg ha−1 nitrogen applied). Soil bulk density, soil total porosity, root length density, nitrogen efficiency and grain yield of winter wheat were measured. Straw return could not only decrease the soil bulk density and increase the soil total porosity of farming layer, but also in subsoil layers, especially at plough pan. Straw return treatments enhanced grain yield significantly, which was mainly due to the increase of 1000-kernel weight. S1N2 produced the maximum grain yield, however, S1N1 induced larger subsoil root length density and the proportion of root system in subsoil layers. Compared with S1N2, the grain yield of S1N1 decreased by 4.0%, but nitrogen partial factor productivity (PFPN) and agronomic nitrogen use efficiency (NAE) increased by 44.0% and 32.6%, respectively. Overall, this study demonstrates that suitable amount of straw returned back to field, combining with nitrogen deficiency moderately, maybe a more eco-friendly and sustainable agricultural technique in the field production.
The long-term use of conventional management practices coupled with the overapplication of synthetic fertilizers by smallholder family farms to meet food demand has negatively impacted the ...environment of farmland. Therefore, improved agronomic management practices are needed to enhance crop productivity. A 3-year (2016–2019) experiment was conducted to evaluate the effects of integrated rotation-tillage management maize/soybean-wheat (MW/SW); chisel plow tillage (CPT), zero tillage (ZT), and plow tillage (PT) on the farmland environment and wheat productivity in the Loess Plateau of China. The results indicated that SW and conservation tillage (CPT and ZT) increased soil nutrient levels and decreased soil pH and C/N values compared with conventional management practices (MW and PT); meanwhile, conservation tillage substantially increased soil moisture (SM, 3.56–16.06 %) compared with PT. Compared with MW and PT, SW and CPT increased aboveground biomass (0.26–4.45 % and 0.73–2.15 %, respectively) and nitrogen content (1.24–2.30 % and 0.26–2.73 %, respectively) during wheat development. Coincidentally, SW increased wheat actual yield (AY, 2.98 %) and maintained wheat theoretical yield (TY) and harvest index (HI) compared with MW; CPT increased wheat grain yield (AY, 6.72 %; TY, 3.28 %) and HI (2.26 %) compared with PT, while ZT caused significantly opposite results. CPT increased nitrogen fertilizer productivity (NfP, 3.28 %), nitrogen uptake efficiency (NupE, 1.19 %), and nitrogen use efficiency (NUE, 1.67 %) compared with PT regardless of crop rotations, while ZT significantly decreased NfP (9.69 %) and NupE (16.99 %) and increased NUE (8.18 %). Nevertheless, crop rotation did not substantially affect wheat nitrogen efficiency. Further correlation and partial least squares path modeling analysis revealed that elevated SM and nitrogen levels due to improved management practices had the potential to improve wheat productivity by regulating wheat growth characteristics. Overall, integrated SW-CPT management was more positive for improving farmland environment and enhancing wheat productivity in the Loess Plateau, which is suitable as a conservation strategy to adjust the cropping structure of smallholder family farms and promote sustainable agricultural development in arid and semiarid agricultural regions.
•Soybean-wheat (SW) and conservation tillage were positive for improving soil nutrients.•SW and chisel plow tillage (CPT) increased wheat growth characteristics.•Zero tillage was detrimental to the development and productivity of wheat.•Wheat growth dynamics could partially explain variations in productivity.•Integrated SW-CPT management is feasible to improve farmland environment and enhance wheat productivity.
The application of nitrogenous fertilizer synergist to coordinate nitrogen transformation process in soil may be an efficient strategy to increase nitrogen use efficiency and decrease environmental ...pollution. However, there are few reports on the application effects of UAN synergistic nitrification and urease inhibitors under the integration of water and fertilizer.
This study aimed to explore effects of urea ammonium nitrate solution (UAN) combined with urease and nitrification inhibitors on yield and nitrogen efficiency of summer maize and its ecological effects under the fertigation, and to provide scientific basis for the efficient utilization of UAN.
The experimental treatments were as follows: no inhibitor treatment (U), nitrification inhibitor treatment (U-D), urease inhibitor treatment (U-N), and the combination of nitrification and urease inhibitors treatment (U-D+N).
Results showed that UAN combined with urease or nitrification inhibitors could significantly reduce the cumulative emission of N2O, and then significantly decreased the N2O warming potential (GWPN2O) and N2O greenhouse gas intensity (GHGIN2O). Compared with U treatment, the cumulative N2O emissions of U-D+N, U-N, and U-D treatments was reduced by 45.7 %, 25.3 % and 35.8 %, respectively. The GWPN2O of U-D+N, U-N and U-D treatments decreased by 45.7 %, 25.3 % and 35.7 %, while GHGIN2O decreased by 50.9 %, 30.3 % and 38.9 % on average, respectively, compared to those of U treatment. Application of urease inhibitors significantly reduced NH3 volatilization. The cumulative NH3 volatilization of U-N and U-D+N treatments was reduced by 30.7 % and 23.4 %, while U-D treament was significantly increased by 12.3 %, respectively, compared to that of the U treatment. In addition, UAN combined with urease or nitrification inhibitor could significantly increase the contents of NO3--N and NH4--N in the 0–20 cm soil layer, and significantly reduced the leaching of NO3--N to the deep soil. The total nitrogen accumulation, grain nitrogen content, nitrogen transport efficiency and post-anthesis assimilation of summer maize were significantly increased, which were beneficial to the improvement of grain yield and economic benefits.
under the fertigation, the synergistic application of UAN with urease and nitrification inhibitors were beneficial to reduce greenhouse gas emissions and ammonia volatilization, improved the nitrogen use efficiency, and then improved the yield and economic benefits of summer maize.
Under the fertigation, UAN combined with urease and nitrification inhibitors were beneficial to emission reduction, high yield, and high efficiency.
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•The combination of DCD and NBPT reduced N2O and NH3 emission under fertigation.•The combination of UAN with DCD and NBPT improved N use efficiency under fertigation.•The combination of UAN with DCD and NBPT increased maize yield under fertigation.
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•Thousand-kernel weight increased with late harvest, increasing grain yield of summer maize.•Late harvest promoted N accumulation after tasseling and N translocation to grain.•N ...accumulation played a crucial role in the early and middle period, and N translocation did in the mid-late period.
The farmers are accustomed to harvesting summer maize around September 20, but the maize has not yet reached physiological maturity in the Huang-Huai-Hai region, which is adverse for grain yield and mechanized harvest. In order to explore the effect of harvest date on grain yield and nitrogen utilization of summer maize, two treatment in 2016 (CK and 10d) and four treatments in 2017 (CK, 3d, 6d, 10d) were conducted. The sowing dates of all treatments were June 13, and the harvest dates of CK, 3d, 6d and 10d were September 20, 23, 26 and 30, respectively. We found that grain yield and thousand-kernel weight of 10d significantly increased by 17.4–19.8% and 16.8–19.6%, respectively, compared to CK. And partial factor productivity of nitrogen of 10d was 17.4–19.7% higher than that of CK. The grain nitrogen concentration of 3d, 6d and 10d increased by 5.4%, 9.0%, and 9.3–10.8% compared to CK, which promoted nitrogen harvest index, physiological nitrogen use efficiency and partial factor productivity of nitrogen. The reason why nitrogen utilization efficiency increased was that late harvest promoted nitrogen accumulation after tasseling and nitrogen translocation to grain. The nitrogen translocation of 6d was 10.0% in 2017 higher, and that of 10d was 25.1% in 2016 and 15.3% in 2017 higher, respectively, compared to CK. The nitrogen accumulation of 10d increased by 39.0% in 2016, and that of 3d, 6d and 10d increased by 46.5%, 51.3% and 57.3% in 2017, compared to CK. In conclusion, the thousand-kernel weight increased with the delay of harvest date, resulting in increases in grain yield of summer maize. The late harvest promoted nitrogen utilization efficiency resulting from higher nitrogen accumulation after tasseling and higher nitrogen translocation to grain. The contribution of nitrogen translocation to grain yield appeared in the mid-late period (September 23–30), while the contribution of nitrogen accumulation after tasseling did in the early and middle period (September 20–26). Considering annual production of winter wheat-summer maize, the optimized harvest date for summer maize is 6–10 days later than the conventional pattern in this study, that is the cumulative growing degree-days after tasseling reach 613.2–711.5 °C at least.
Objectives of this study were to investigate the effects of supplementing rumen-protected methionine (RP-Met), threonine (RP-Thr), isoleucine (RP-Ile), and leucine (RP-Leu) individually or jointly to ...a low-protein diet, on the performance of lactating dairy cows, as well as to determine the effects of these amino acids (AA) on the mammalian target of rapamycin (mTOR) in vivo. Ten lactating Holstein cows were randomly allocated to a repeated 5 × 5 Latin square experiment with five 19-d periods. Treatments were high-protein diet (16% crude protein, positive control; HP), low-protein diet (12% crude protein, negative control; LP), LP plus RP-Met (LPM), LP plus RP-Met and RP-Thr (LPMT), and LP plus RP-Met, RP-Thr, RP-Ile, and RP-Leu (LPMTIL). The dry matter intakes (DMI) of the LP, LPM, and LPMT diets were lower than that of the HP diet, whereas the DMI of the LPMTIL diet was intermediate between the HP diet and the other LP diets. Supplementing RP-Met to the LP diet increased the yields of milk and milk protein, increased the content of milk urea N, and tended to increase milk N efficiency. Co-supplementation of RP-Thr with RP-Met resulted in no further milk production increase. Co-supplementation of all 4 rumen-protected amino acids (RP-AA) increased milk and lactose yields to the level of the HP diet and tended to increase milk protein yield compared with the LPMT diet. We found no significant differences in the contents and yields of milk components between the LPMTIL and HP diets except for a lower milk urea N content in the LPMTIL diet. Venous concentrations of the measured AA were similar across the LP and LP diets supplemented with RP-AA. Relative to levels of the HP diet, LP diets had higher venous concentrations of Met and Gly and tended to have higher Phe concentration and lower concentrations of Val and BCAA. The LPMTIL diet had higher venous concentrations of Arg, Lys, Met, Phe, and Glu, and a lower Val concentration. Phosphorylation status of the measured mTOR components in LPM and LPMT treatments were similar to those in the LP treatment but phosphorylation status of mTOR and eIF4E-binding protein 1 (4eBP1) in LPMTIL treatment were higher. The phosphorylation rates of eukaryotic elongation factor 2 (eEF2) in the 4 LP and LP plus RP-AA diets were higher than that of the HP diet. Overall, results of the present study supported the concept that under the relatively short time of this experiment, supplementing RP-AA, which are believed to stimulate the mTOR signal pathway, can lead to increased milk protein yield. This increase appears to be due to increased DMI, greater mTOR signaling, and greater eEF2 activity.
•REN and ANUE were 6.8 % and 33 % in Chinese plastic-shed vegetable production.•Exponential relationship well explains the response of N2O emission to N rate.•Combined synthetic fertilizer with ...manure at > 800 kg N ha−1 increase N2O emission.•There is a trade-off between soil fertility improvement and N2O mitigation.
Currently, China has approximately four million hectares of intensively cultivated plastic-shed vegetable production, i.e., with excessive nitrogen (N) fertilization and high irrigation. Plastic-shed vegetable production has helped meet the rapidly increasing consumer demand for fresh vegetables while improving heat, light, and land utilization efficiencies, resulting in very high vegetable yield. We collected all studies from the 1980s to 2020 on N2O emissions and N fertilization associated with plastic-shed vegetable production at 40 field sites in China. Fertilizer N utilization efficiencies and N2O emissions that were affected by fertilizer N rate and type, irrigation, growth duration, nitrification inhibitors, and soil properties were systematically examined. The results revealed that fertilizer N efficiencies in plastic-shed vegetable production significantly decreased with increasing N fertilization rate. The average N recovery efficiency (REN) and apparent N use efficiency (ANUE) were 6.8 % and 33 %, respectively; much lower than those of cereal crop production in the same region. In fruit and leafy vegetable production, N2O emissions exhibited an exponential and linear relationship with the fertilizer N rate, respectively, and the average contributions of fertilizer N to N2O emissions were 68 % and 70 %, respectively. Compared with synthetic N fertilizer or manure alone, combination of synthetic fertilizer with animal manure significantly increased the N2O emissions and emission factors (EFs) at high N fertilization rates (>800 kg N ha−1 season−1), but there were no significant differences among fertilizer types at N rate <800 kg N ha−1 season−1. Nitrification inhibitors reduced N2O emissions by 24.0 % (95 % confidence intervals CI: 19.2 %–28.9 %), and water-saving irrigation is the other effective measure to reduce emissions. Plastic-shed soils with neutral pH, high organic carbon content (> 30 g kg−1), growth period of >100 d, and higher irrigation increased the responses of N2O emission to N fertilization. As plastic-shed soils are continuously and intensively farmed, soil properties will be negatively affected, and should be considered together with fertilization and irrigation to maintain high vegetable yield and low N2O emissions. Our study highlighted that the exponential relationship was more appropriate to predict the N2O emissions in plastic-shed vegetable production, and our findings help to optimize fertilizer N input with consideration of crop yield and greenhouse gas emission.
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•Nutrient Expert (NE), is designed through adoption of 4R nutrient stewardship.•Results show that NE achieved higher yields, higher profitability, and lower environmental risks.•An ...outstanding advantage of NE is user-friendly and can be easily acquired by all farmers with smartphones.
Fertilizer has revolutionized crop production, but a lack of evidence-based fertilizer usage has resulted in negative economic and environmental ramifications, particularly for smallholder farmers. This study aimed at developing an innovative nutrient recommendation approach, Nutrient Expert (NE), for improving yields of maize, wheat, and rice while optimizing fertilizer input through adoption of 4R (applying the right source of nutrients at the right rate, time and place) nutrient stewardship technologies, and evaluating the large-scale performance on crop productivity and the environmental impact of cropping systems. Thus, we compared NE to current farmers’ practice (FP) and soil test-based fertilizer application (ST) for 1,534 farm field experiments in order to validate the benefits of NE on both crop productivity and environmental protection in the main cereal production areas in China. Overall, the NE treatment achieved 4.4 % higher grain yield and 5.8 % more profit over FP, more yield for rice, but no differences for maize and wheat over ST. Nutrient Expert required 29.0 % and 14.7 % less fertilizer N than FP and ST, respectively. The NE recommendations improved the nitrogen (N) recovery efficiency by 10.8–13.4 percent points over FP across the 1,534 sites. Using the NE approach, on average, reactive N losses and greenhouse gas (GHG) emissions were reduced by 36.2 % and 21.5 % over FP, 16.0 % and 9.9 % over ST, respectively. The NE, as a user-friendly tool, is widely applicable across farm types and climatic regions. It could be beneficial for improving fertilizer use efficiency and maintaining strategic food security for smallholder production areas in China where N fertilizer is inappropriate and usually over applied. This approach could potentially be expanded to help reduce N losses and GHG emissions in other regions globally.
This study tested the effects of energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels on whole-body energy and N ...partitioning of dairy cattle. Six rumen-fistulated, second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were randomly assigned to a 6 × 6 Latin square design in which each experimental period consisted of 5 d of continuous abomasal infusion followed by 2 d of rest. A total mixed ration consisting of 42% corn silage, 31% grass silage, and 27% concentrate (dry matter basis) was formulated to meet 100 and 83% of net energy and metabolizable protein requirements, respectively, and was fed at 90% of ad libitum intake by individual cow. Abomasal infusion treatments were saline (LMP-C), isoenergetic infusions (digestible energy basis) of 1,319 g/d of glucose (LMP-GG), 676 g/d of palm olein (LMP-LG; major fatty acid constituents are palmitic, oleic, and linoleic acid), or 844 g/d of essential AA (HMP-C), or isoenergetic infusions of 1,319 g/d of glucose + 844 g/d of essential AA (HMP-GG) or 676 g/d of palm olein + 844 g/d of essential AA (HMP-LG). The experiment was conducted in climate respiration chambers to determine energy and N balance in conjunction with milk production and composition, nutrient digestibility, and plasma constituents. Infusion of GG and LG decreased dry matter intake, but total gross energy intake from the diet plus infusions was not affected by GG or LG. Furthermore, GG or LG did not affect total milk, protein, or lactose yields. Infusing GG or LG at the HMP level did not affect milk production differently than at the LMP level. Infusion of GG stimulated energy retention in body tissue, increased plasma glucose and insulin concentrations, decreased lipogenic metabolites in plasma, and decreased milk fat yield and milk energy output. Nitrogen intake decreased and milk N efficiency increased in response to GG, and N retention was not affected. Infusion of LG tended to increase metabolizable energy intake, increased milk fat yield and milk energy output, increased plasma triacylglycerides and long-chain fatty acid concentrations, and had no effect on energy retention. Infusion of LG decreased N intake but did not affect milk N efficiency or N retention. Compared with the LMP level, the HMP level increased dry matter intake, gross and metabolizable energy intake, and total milk, fat, protein, and lactose yields. Milk energy output increased at the HMP level, and protein level did not affect total energy retention. Heat production increased at the HMP level, but only when GG and LG were infused. The HMP level increased N intake, milk N output, and plasma urea concentration, tended to increase N retention, and decreased milk N efficiency. Regardless of protein level, GG promoted energy retention and improved milk N efficiency, but not through increased milk protein yield. Infusion of LG partitioned extra energy intake into milk and had no effect on milk N efficiency.
The objective of this study was to test the effects of inclusion of hop pellets (HP) and oak tannin extracts (OT) alone or in combination on N efficiency, methane (CH4) emission, and milk production ...and composition in 2 experiments with dairy cows fed low-N rations supplemented with linseed. In both experiments, 6 lactating Holstein cows were assigned to 3 dietary treatments in a 3 × 3 duplicated Latin square design (21-d periods). Cows were fed a total mixed ration at a restricted level to meet their nutrient requirements. In experiment 1, 169 g dry matter (DM) of OT or 56 g DM of HP was included separately in the control diet (C1). In experiment 2, the additives were included together (OT-HP) in the control diet (C2) similar to C1. Diet C2 was compared with a control without linseed (C0). In experiment 1, the supplementation of the control diet with OT decreased urinary N excretion by 12%. In experiment 2, the combination of OT and HP decreased urinary N by 7%. Oak tannin extracts and HP alone or in combination did not influence the daily enteric CH4 production of cows. Cows fed diet C0 produced 17% more enteric CH4 daily than those fed diet C2. Intake of diet C2, which contained 6.7% extruded linseed on a DM basis (experiment 2), decreased the sum of 6:0 to 14:0 fatty acids (−16%) and palmitic acid (−26%) and increased the stearic acid (+50%), oleic acid (+36%), vaccenic acid (trans-11 18:1; +285%), rumenic acid (cis-9,trans-11 18:2; +235%), and α-linolenic acid (+100%) in milk fat. The supplementation of diet C2 with the OT-HP mixture further improved the milk's fatty acid composition. Intake of the OT alone increased α-linolenic acid by 17.7% (experiment 1). The results of this study show that at the economically acceptable dose we tested, hops had no effect on urinary N excretion, CH4 emission, milk production, and milk composition. By contrast, supplementation of diets with oak tannin extract can be considered for reducing urinary N excretion. The combination of oak tannin and hops had no more effect than oak tannin alone except on the milk fatty acid profile, which was favorably influenced from a nutritional point of view.
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