Nutrient Efficiency Research Articles

Performance evaluation of a pilot wetland system for wastewater treatment

Wetland systems are inexpensive and easy-to-operate wastewater systems and are widely used globally at different scales for the safe treatment of wastewater. This study aims to evaluate a pilot-scale vertical flow wetland system treating wastewater under different loadings. The wetland system was constructed using indigenous plants (Imperata cylindrical) and operated using actual wastewater for twelve-months. Samples from influent and effluent of the wetland system were collected weekly. They were analyzed for parameters listed in the Kuwait Environment Public Authority standards for reuse in irrigation, such as organic matter, nutrients, heavy metals, and microorganisms. The results showed that the high hydraulic loading rate (1.67 m3/m2.d) phase was more efficient than the low hydraulic loading rate (1.04 m3/m2.d) phase in terms of organics and nutrient removal efficiency. The range of the removal efficiency of organic matter in low and high loading rates was around 48.5–49.0% and 59.1–59.1%, respectively. In addition, the range of the removal efficiency of nutrients in low and high loading rates was around 43.7–67.7% and 24.7–76.6%, respectively. Moreover, the range of the removal efficiency of heavy metals under the low and high loading rates was − 134.3–93.8% and − 1545.7–92.6%, respectively. It was evident that he metals were leaching from the soil. Moreover, it was found that the system performance was closely linked to the ambient temperature effects during the start-up (r = 0.59) and high hydraulic loading (r = 0.43) phases for example. While ambient temperature has wider effects on wetland biota, its effects on the plants are more pronounced. In conclusion, wetland systems can be constructed using indigenous plants to treat office wastewater efficiently under the harsh climate conditions of Kuwait with adjustments in capacity, loading rates, and operational conditions.

Potassium Use Efficiency of Natural Zeolite-Based Potassium Fertilizer in Oil Palm Seedlings (Elaeis guineensis Jacq.) Using Peat Soil Media

Potassium is the most needed macronutrient for oil palm. However, the efficiency of potassium fertilization on peatlands is low due to leaching. One of the exertions to improve this fertilization's efficiency is peat soil amelioration and engineering fertilizer technology so that plants can absorb nutrients more efficiently. This study aims to evaluate the effectiveness of zeka fertilizer, a modified potassium fertilizer made from natural zeolite, on oil palm seedlings in peat soil. The study used a completely randomized design with five treatments and three replications. The treatments were (1) K0 = Control/no fertilizer; (2) K1 = standard fertilizer, namely: urea + TSP + KCl + dolomite; (3) K2 = urea + TSP + zeka-1 + dolomite; K3 = urea + TSP + zeka-2 + dolomite; K4 = urea + TSP + zeka-3 + dolomite. The results proved that, in general, zeka fertilizer (K2, K3, and K4) produced better seedling growth and nutrient use efficiency than the standard fertilization treatment of oil palm seedlings (K1). The best treatment (K3) resulted in the highest growth and nutrient efficiency. K3 treatment resulted in seedling height and stem diameter by 7.7% and 9.2%, respectively, compared to K1. Furthermore, the dry biomass of the shoot and roots produced by the K3 treatment was 39.2% and 33.9% higher, respectively, than that produced by the K1 treatment. The agronomic efficiency, Apparent Recovery efficiency, Physiological efficiency, and Partial Factor Productivity of K3 treatment were 59.91%, 33.23%, 18.57%, and 39.16% higher than K1, respectively.

Effect of Supplementing a Bacillus Multi-Strain Probiotic to a Post-Weaning Diet on Nutrient Utilisation and Nitrogen Retention of Piglets

Probiotics are suggested to improve pig health, nutrient utilisation, performance, and they may reduce nitrogen (N) pollution. However, the effectivity of a single strain might be different from that of a multi-strain. The study was conducted to investigate the effect of a novel Bacillus multi-strain on nutrient digestibility, energy utilisation, and N retention in weaned piglets using an European diet. The experiment consisted of a control diet (CD) and a supplemented diet (SD). The probiotic used for SD consisted of B. amyloliquefaciens—516 and B. subtilis—541. A total of eight boars/treatment were weaned (day 0; 8.5 kg body weight). Only boars were used to ease the collection of urine. Until day 10, piglets were fed ad libitum and were housed in pairs; from day 11, piglets were fed semi ad libitum (feeding level 3.2× metabolic body weight) and were housed individually. From day 14, faecal and urine were collected twice daily. Piglets were humanely euthanised at day 19 (15.0 kg bodyweight) after which the jejunum, ileum, and colon content were collected. In faeces, the apparent total tract digestibility (ATTD) of, amongst others, DM, organic matter (OM), crude protein (CP), non-starch polysaccharides (NSP), and subsequently net energy (NE) were calculated using titanium dioxide as an indigestible marker. In the jejunum and ileum, the apparent digestibility of CP was estimated, and in the ileum, the apparent AA digestibility was measured. In urine, the N content was measured to determine N retention. The volatile fatty acid (VFA), branched-chain fatty acid (BCFA), and lactic acid content were analysed in the colon and faeces. The apparent CP digestibility in the jejunum and ileum was not affected by treatment (p > 0.05), and no effect was observed on the apparent ileal digestibility of AA (p > 0.05). Supplementation with the multi-strain probiotic improved the ATTD of DM (p = 0.01; +1.3%) and OM (p = 0.02; +1.2%) and tended to improve the ATTD of CP (p = 0.10; +2.2%) and NSP (p = 0.07; +1.9%). The multi-strain probiotic also improved the NE value (p = 0.02; +0.2 MJ/kg DM) and improved N retention (p = 0.05; +1.6%). Supplementation did not influence the VFA, BCFA, and lactic acid content in the faeces (p > 0.05). However, in the colon, supplementation did influence the lactic acid content (lower; p = 0.01) and tended to influence the valeric acid content (higher; p = 0.09). In conclusion, results from the current study suggest that the multi-strain probiotic has the potential to contribute to improve nutrient efficiency in weaned piglets. More research needs to be conducted to identify the impact of the improved nutrient utilisation on gut health in post-weaned pigs as well as environmental pollution.

Alteration of carbon and nitrogen allocation in winter wheat under elevated ozone

Tropospheric ozone accelerates senescence and shortens grain filling, consequently affecting the remobilization and allocation efficiency of aboveground biomass and nutrients into grains in cereal crops. This study investigated carbon (C) and nitrogen (N) concentrations repeatedly in shoot biomass during the growth period and in grain after the harvest in eighteen wheat genotypes under control and ozone treatments in open-top chambers. Season-long ozone fumigation was conducted at an average ozone concentration of 70 ppb with three additional acute ozone episodes of around 150 ppb. Although there were no significant differences in straw C and N concentrations between the two treatments, the straw C:N ratio was significantly increased after long-term ozone fumigation, and the grain C:N ratio decreased under elevated ozone without significance. Grain N concentrations increased significantly under ozone stress, whereas N yield declined significantly due to grain yield losses induced by ozone. Moreover, different indicators of N use efficiency were significantly reduced with the exception of N utilization efficiency (NUtE), indicating that elevated ozone exposure reduced the N absorption from soil and allocation from vegetative to reproductive organs. The linear regression between straw C:N ratio and productivity indicated that straw C:N was not a suitable trait for predicting wheat productivity due to the low coefficient of determination (R2). Nitrogen harvest index (NHI) was not significantly affected by ozone stress among all genotypes. However, elevated ozone concentration changed the relationship between harvest index (HI) and NHI, and the reduced regression slope between them indicated that ozone exposure significantly affected the relationship of N and biomass allocation into wheat grains. The cultivar “Jenga” showed optimal ozone tolerance due to less yield reduction and higher NUE after ozone exposure. The genotypes with higher nutrient use efficiencies are promising to cope with ozone-induced changes in nitrogen partitioning.

Impact analysis of hydraulic loading rate and antibiotics on hybrid constructed wetland systems: Insight into the response to decontamination performance and environmental-associated microbiota

Hybrid constructed wetlands (HCWs) are a promising solution for water ecology and environmental treatment, not only for conventional types of water pollution but also for antibiotics. Among the critical parameters for wetlands, the hydraulic loading rate (HLR) is especially important given the challenges of antibiotics treatment and frequent extreme rainfall. To investigate the removal performance of different HLRs on nutrients and antibiotics, as well as the response of antibiotics to nutrient removal, and the impact of HLRs on microbial communities, new HCWs with vertical flow constructed wetlands (VFCWs) and floating constructed wetlands (FCWs) in series were built. The results of the study showed that: (1) HCWs are highly effective in removing chemical oxygen demand (COD), NH4+−N, NO2−−N, and total phosphorus (TP) at low HLR (L_HLR), with removal efficiencies as high as 97.8%, 99.6%, 100%, and 80.5%. However, high HLR (H_HLR) reduced their removal efficiencies; (2) The average removal efficiency of fluoroquinolones (FQs) under different HLRs was consistently high, at 99.9%, while the average removal efficiency of macrolides (MLs) was 96.3% (L_HLR) and 88.4% (H_HLR). The removal efficiency of sulfonamides (SAs) was susceptible to HLRs, and the removal of antibiotics occurred mainly in the rhizosphere zone of wetland; (3) High concentrations of antibiotics in HCWs were found to inhibit and poison plant growth and to reduce the removal efficiency of TP by 12%. However, they had a minor effect on the removal efficiency of carbon and nitrogen nutrients; (4) H_HLR altered the diversity and abundance of microbial communities in different compartments of the wetland and also reduced the relative abundance of Bacillus, Hydrogenophaga, Nakamurella, Denitratisoma and Acidovorax genera, which are involved in denitrification and phosphorus removal processes. This alteration in microbial communities was one of the main reasons for the reduced performance of nitrogen and phosphorus removal.

89 Physiological Mechanisms Related to Feed Efficiency of Beef Cattle

Abstract Improving feed efficiency is essential for the sustainability of the US beef production system. However, achieving this goal is challenging due to various factors such as diet types, genetics, environments, and industry segmentation. To address these difficulties, it is critical to have a fundamental understanding of what contributes to efficient nutrient utilization and feed resources, which can guide future genetic selection and production practices. Despite recent progress, the regulation of feed intake in growing and finishing cattle remains incompletely understood, hindering advances in feed efficiency. Recent research has aimed to advance the hepatic oxidation theory to growing and finishing cattle fed high-concentrate diets and explored the control of appetite by gut peptide hormones. Other factors contributing to variation in feed efficiency include nutrient metabolism and hormonal control of metabolism. Previous research is limited by a lack of in-depth analysis of metabolism due to the inability to time sample collection relative to feed consumption and account for correlations among metabolites. The role of fat metabolism in the rumen has been associated with epithelial inflammation, while inflammation of the gut has been identified as a contributing factor to inefficiencies in nutrient utilization. However, there is still a need to further understand the role of fatty acid metabolism in the induction of inflammation. An issue that limits the further understanding of efficiency is that a wide variety of feedstuffs are utilized by the industry and small changes in the nutrient composition of a diet can have large impacts on efficiency. Therefore, it is important to consider the utilization efficiency of specific nutrients rather than general feed efficiency. Nitrogen utilization efficiency is becoming increasingly important due to the significant economic and environmental ramifications of inefficiencies in nitrogen utilization. There is growing evidence that precision feeding of protein to match requirements can reduce nitrogen excretion without compromising growth and efficiency. In conclusion, a better understanding of the underlying biology contributing to nutrient utilization is crucial for improving feed utilization efficiency in the US beef production system, which will enhance the sustainability of the US beef production system.

221 Increasing Functional Amino Acid Ratios Does Not Improve Growth Performance in Pigs Raised Under Poor Sanitary Conditions When Fed with Individual Precision Feeding Or Conventional Feeding Systems

Abstract Immune system activation redirects dietary nutrients to defense mechanisms, thereby impairing growth performance of pigs. Supplementing pigs with functional amino acids (AA) such as Met, Thr and Trp was shown to support the immune system and reduce the negative effects on growth. However, pigs respond differently to immune stressors which increase herd variability. In this context, individual precision feeding (IPF) might be an alternative approach to reduce herd variability and increase nutrient efficiency in immune challenged pigs. This study aimed to evaluate growth performance, body composition, nitrogen (N) efficiency and haptoglobin and triglycerides serum concentration in growing pigs raised in poor sanitary conditions (PoorSC). The PoorSC was characterized by oral inoculation with 2 × 109 cfu of Salmonella typhimurium and manure spreading on the pen floor. Sixty gilts (23 ± 2.8 kg BW) were distributed in BW blocks according to a 2 dietary (D) × 2 feeding system (FS) factorial arrangement composed of to 2 diets [control (CN): INRA ideal AA ratio or supplemented (AA+) 120% of the ideal ratio for Met, Thr and Trp] and 2 feeding systems [conventional (GP) or IPF]. GP pigs were fed with a unique diet that matched the SID Lys requirement of the 80th-percentile pig at the beginning of the trial whereas the IPF pigs received a diet tailored daily to each pig requirement. All pigs were housed in the same pen and fed ad libitum during 28 experimental days with automatic feeding stations able to provide to each pig the assigned diet. Body composition was obtained by dual X-ray absorptiometry at days 0 and 28 and blood samples were collected at d 28. Data were analyzed with D and FS and their interaction as main fixed factors and body weight (BW) blocks as a random effect (Table 1). Haptoglobin serum concentration increased from d 0 to 28 regardless of FS and D (P < 0.10). IPF pigs fed with CN diet had the lightest BW at the end of the trial (P ≤ 0.10; FS × D), whereas BW was similar for the other treatments. However, across diets, IPF pigs had final BW, and protein, ADG, G:F, protein and lipid deposition, N intake and excretion and circulating triglycerides that were less than GP pigs. N utilization efficiency was similar across treatments. Additionally, increasing the provision of the studied functional AA did not improve pig performance. Thus, showing no benefits in increasing AA ratios for growth and immune response. The increased triglycerides concentration and low protein and lipid deposition suggests that IPF pigs prioritized the immune system to the expense of protein and lipid accretion. In conclusion, AA supplementation and IPF do not improve growth performance and N efficiency of pigs raised in poor sanitary conditions.

Hydrography, inorganic nutrients and chlorophyll a linked to sea ice cover in the Atlantic Water inflow region north of Svalbard

Changes in the inflow of Atlantic Water (AW) and its properties to the Arctic Ocean bring more warm water, contribute to sea ice decline, promote borealisation of marine ecosystems, and affect biological and particularly primary productivity in the Eurasian Arctic Ocean. One of the two branches of AW inflow follows the shelf break north of Svalbard, where it dominates oceanographic conditions, bringing in heat, salt, nutrients and organisms. However, the interplay with sea ice and Polar Surface Water (PSW) determines the supply of nutrients to the euphotic layer especially northeast of Svalbard where AW subducts below PSW. In an effort to build up a time series monitoring the key characteristics of the AW inflow, repeat sampling of hydrography, macronutrients (nitrate, phosphate and silicate), and chlorophyll a (chl a) was undertaken along a transect across the AW inflow at 31°E, 81.5°N since 2012 — first during late summer and in later years during early winter. Such time series are scarce but invaluable for investigating the range of variability in hydrography and nutrient concentrations. We investigate linkages between late summer hydrographic conditions and nutrient concentrations along the transect and the preceding seasonal dynamics of surface chl a and sea ice cover in the region north of Svalbard. We find large interannual variability in hydrography, nutrients and chl a, indicating varying levels of nutrient drawdown by primary producers over summer. Sea ice conditions varied considerably between the years, impacting upper ocean stratification, light availability and potential wind-driven mixing, with a strong potential for steering chl a concentration over the productive season. Early winter measurements show variable efficiency of nutrient re-supply through vertical mixing when stratification was low, related to autumn wind forcing and sea ice conditions. While this re-supply elevates nutrient levels sufficiently for primary production, it likely happens too late in the season when light levels are already low, limiting the potential for autumn blooms. Such multidisciplinary observations provide insight into the interplay between physical, chemical and biological drivers in the marine environment and are key to understanding ongoing and future changes, especially at this entrance to the central Arctic Ocean.

208 Effect of SID LYS Level with Constant Non-Essential Amino Acids

Abstract Many investigations on the effect of low protein diets reduce crude protein (CP) and have a constant standardized ileal digestible (SID) LYS resulting in reductions in ADG, ADFI, and gain:feed is some cases. This experiment was conducted to determine the impact of maintaining constant non-essential amino acids and changing SID LYS and other essential amino acids. For the experiment, 288 pigs (~22 d of age, 6.61 ± 0.95 kg, 8 replicates/treatment, 6 pigs/pen) were stratified by body (BW) and randomly allotted to one of 6 treatments in a randomized complete block design. Non-essential amino acids were fixed in all diets and synthetic amino acids were added to increase SID LYS from 1.15% to 1.4% while maintaining constant ratios of MET+CYS, THR, TRP, VAL, and ILE to LYS. Diets were corn, wheat, barley, and soy based with 1.1% corn starch in the least SID LYS diet. Synthetic amino acids were added to the diet at the expense of corn starch to maintain non-essential amino acid levels. The CP ranged from 17.8% when SID LYS was 1.15% and 18.6% when SID LYS was 1.4%. Experimental diets were fed for 21 d. Body weight, feed disappearance, visual fecal scores, and visual piglet scores were measured. Visual fecal scores (1 = normal to 4 = watery) and visual pig appearance scores (1 = pale and hairy to 4 = normal color and well-rounded muscle) were assessed on ordered likert scales to determine the probabilities of observing a more normal stool quality and a worse visual appearance, respectively. Performance data were analyzed as a general linear model. Stool quality and visual appearance were analyzed as a generalized linear mixed model. Contrasts were used to test linear and quadratic effects of dietary SID LYS. Results of the experiment are presented in Table 1. Increasing SID LYS with constant non-essential amino acids did not affect ADG or BW. The ADFI was linearly decreased (P < 0.1) and gain:feed was linearly increased (P < 0.0001) with increasing SID LYS (Table 1). Stool quality was not affected. Visual appearance of the pigs was quadratically affected (P < 0.05) by changing SID LYS. Pigs that had consumed diets with the lowest or highest SID LYS had the best visual appearance (lowest probability). The results of the current experiment differ suggest SID LYS may regulate feed intake and nutrient efficiency, but BW gain is not affected when non-essential amino acids are held constant. This differs from cases where CP is reduced, which results are decreased growth in many cases.

Occupational safety assessment of biogenic urea nanofertilisers using in vitro pulmonary, and in vivo ocular models

Nanomaterials (NMs) are now gaining popularity to be used in agriculture as fertilisers to reduce the dose of conventional fertilisers and enhance nutrient use efficiency. Urea has found its application as a conventional nitrogenous fertiliser since long, however, the nutrient use efficiency of the bulk form of urea is low due to issues related to ammonia volatilisation. This study proposes a biogenic synthesis route to develop urea nanoparticles that can be used as nano-fertiliser for better uptake and hence improved nutrient efficiency. Large scale production and widespread application of these nano-fertilisers to the agricultural fields will enhance the direct exposure to workers and farmers. Therefore, the occupational safety evaluation becomes critical. In this study, we report a new method for synthesis of urea nanoparticles (TNU, absolute size: 12.14 ± 7.79 nm) followed by nano-safety evaluation. Herein, the pulmonary and ocular compatibilities of TNU were investigated in vitro and in vivo respectively. The assay for cellular mitochondrial activity was carried out on human lung fibroblasts (WI-38) under varied TNU exposure concentrations up to 72 h. The acute biocompatibility effect, ocular irritation and sub-lethal effects were measured on New Zealand Rabbit. The results show that TNU do not exhibit any cytotoxicity and detrimental cell mitochondrial activity up to the highest tested concentration of 1000 μg/mL and 72 h of testing. The animal experiment results also show that neither acute nor sub-lethal toxic effects can be detected after TNU ocular instillation up to 21 days when tested up to environmentally relevant concentration of 15 μg/mL. These results suggest the occupational safety of biogenic urea nanoparticles and support its application as nanofertiliser.

Role of Temporal Zn Fertilization along with Zn Solubilizing Bacteria in Enhancing Zinc Content, Uptake, and Zinc Use Efficiency in Wheat Genotypes and Its Implications for Agronomic Biofortification

Wheat (Triticum aestivum L.) is a vital cereal crop for food security in Pakistan. In Zn-deficient soils, its productivity and quality suffer, affecting grain yield, Zn bioavailability, and nutrition, which can lead to malnutrition. Field experiments were conducted using factorial randomized block design at the Agricultural Research Institute (ARI) Tarnab, Peshawar, Pakistan to evaluate the impact of wheat genotypes (G1-TRB-72-311 synthetic hexaploid, G2-TRB-89-348 advanced line, and G3-Pirsabak-19-approved variety), Zn application methods (AM1: no Zn application, AM2: seed priming with 0.5% Zn, AM3: soil application of 10 kg ha−1 Zn, and AM4: foliar application of 0.5% Zn), and the experiment also explored the use of ZSB (BF1: with bacteria, BF0: without bacteria) to cope with Zn deficiency. The study revealed significant impacts on wheat’s Zn content, uptake, and nutrient efficiency, arising from genotypes variance, Zn application approaches, and ZSB. TRB-72-311 synthetic hexaploid genotype with 0.5% foliar Zn and ZSB excelled, enhancing grain (17.8%) and straw Zn (23.1%), increasing total Zn uptake (55.0%), reducing grain phytic acid (11.7%), and boosting Zn-related efficiencies in wheat. These results prompt further discussion regarding the potential implications for agricultural practices. In conclusion, utilizing the TRB-72-311 genotype with 0.5% foliar Zn application and ZSB enhances wheat’s Zn content, uptake, grain quality, and addresses malnutrition.

Effects of microbial fertilizer and irrigation amount on growth, physiology and water use efficiency of tomato in greenhouse

A pot experiment was conducted to investigate the effect of microbial fertilizer and irrigation regime on growth, physiology, water use efficiency (WUE) of tomato plants and soil nutrients. Microbial fertilizers: bacillus subtilis fertilizer (B.s.), bacillus polymyxa fertilizer (B.p.) and combined bacillus species (B.c.) were used as microbial fertilizers in the study, and plants treated without bacillus fertilizer were taken as control (CK). Three irrigation levels were set, i.e., full irrigation (I1) which plants were irrigated to 95 % field capacity (θf), and two deficit irrigations which were 2/3 I1 (I2) and 1/3 I1 (I3), respectively. The result showed that microbial fertilizers enhanced leaf photosynthesis rate (An), transpiration rate (Tr), relative chlorophyll content (CHL), nitrogen index balance (NBI) and leaf water potential (Ψl) in addition to increased plant root length, root surface area, root volume; and promoted plant water consumption, dry matter (DM) and plant water use efficiency (WUE). The content of nitrogen in leaf ([N]leaf), nitrogen use efficiency (NUE), the mineral nitrogen and soil microbial nitrogen content (MBN) were significantly improved by microbial fertilizer. Compared to CK, B.s., B.p. and B.c. increased An by 17.96 %, 11.77 % and 6.83 %, respectively. B.s. fertilizer significantly increased MBN and root length by 21.99 % and 55.08 % than CK. Deficit irrigations decreased An, Tr, stomatal conductance (gs), and improved intrinsic water use efficiency (WUEi) and instantaneous water use efficiency (WUEinst). Deficit irrigation depressed leaf area, Ψl, CHL, NBI, root length, root surface area and root volume, hereby declined plant water consumption, and optimized plant WUE. In this study, microbial fertilizers mitigated negative effects of deficit irrigation on photosynthesis and DM and improved WUE. Compare to CK and other microbial fertilizers, B.s fertilizer treated plants possessed enhanced plant water status, higher leaf gas exchange rates, more developed root system, higher plant nitrogen accumulation and NUE. Hereby, the B.s. fertilizer is an optimal strategy to mitigate water stress in tomato plants and promoted plants growth.

Efficient Utilization Mechanism of Soil Moisture and Nutrients with Ridge Film Furrow Seeding Technology of Sloping Farmlands in Semi-Arid and Rain-Fed Areas

How to improve the utilizations of water and nutrient is a research hotspot of sloping farmland in semi-arid and rain-fed areas. In this study, the spatial changes of soil moisture, nutrients, and roots under different tillage modes, as well as the efficient utilization mechanism of soil moisture and nutrients from rain-fed maize on three mulching treatments (no surface covering, ridge film and straw mulch and ridge film mulch) and two slope treatments (5° slope and 10° slope) of sloping farmlands were studied at the Nationally Agricultural Environment Fuxin Observation and Experiment Station in China through a micro-zone simulation and a long-term positioning experiment. The results indicated that ridge film mulch and furrow seeding significantly improve the water use efficiency and partial factor productivity of the plants in sloping farmlands, with the highest increases being 51.33% and 45.05%. By analyzing the coordinated relationship between water, nutrients, and roots, it was found that ridge film furrow seeding technology can significantly affect the spatial distribution of water, nutrients, and roots in different soil layers, and improves the effective coefficient of soil water and nutrients. The effective coefficient of ridge film and straw treatment was 2.53, while the average value of the effective coefficient of ridge film treatment was 1.39. Further analysis found that the degree of consistency between the root system, water, and nutrient barycenter was highly correlated with the effective coefficients of water and nutrients. Visual radar map analysis revealed that root development limits the improvement availability of the efficient use of water and nutrients in the soil. Promoting root development indicators and root spatial distribution through ridge film coverage was an effective way to improve the efficient use of maize water and nutrients. The ridge film mulching promoted the root development index and root spatial distribution, thus improving the efficient use of water and nutrients in maize. Overall, the ranking of the regulation effect was as follows: ridge film and straw mulch > ridge film mulch > no mulch, and 5° slope > 10° slope. This research provided a theoretical basis for the enhancement of use efficiency in water and nutrients in sloping farmlands.

Does day length matter for nutrient responsiveness?

For over 2500 years, considerable agronomic interest has been paid to soil fertility. Both crop domestication and the Green Revolution shifted photoperiodism and the circadian clock in cultivated species, although this contributed to an increase in the demand for chemical fertilisers. Thus, the uptake of nutrients depends on light signalling, whereas diel growth and circadian rhythms are affected by nutrient levels. Here, we argue that day length and circadian rhythms may be central regulators of the uptake and usage of nutrients, also modulating responses to toxic elements (e.g., aluminium and cadmium). Thus, we suggest that knowledge in this area might assist in developing next-generation crops with improved uptake and use efficiency of nutrients.

Enhancing Drought Tolerance and Fruit Characteristics in Tomato through Exogenous Melatonin Application

Drought stress not only affects the growth and development of tomato seedlings but also leads to a significant decrease in tomato fruit yield. Previous studies have shown that melatonin plays a crucial role in regulating plant tolerance to drought stress. The present study was conducted to investigate the impact of exogenous melatonin on the growth and development of tomato seedlings under drought stress, as well as its potential in improving fruit yield and quality. Our findings demonstrate that drought stress strongly suppressed growth and biomass accumulation, reduced photosynthetic pigments, and inhibited photosynthesis. Conversely, melatonin treatment led to a notable increase in plant height, stem diameter, aboveground biomass, and relative water content of tomato seedlings by 16.67%, 7.39%, 10.58%, and 13.31%, respectively, compared to the drought treatment. Moreover, the chlorophyll content increased by 40.51%, and the net photosynthetic rate increased by 1.2 times. Furthermore, the application of melatonin under drought stress resulted in a decrease in osmoregulation substances, reduced accumulation of reactive oxygen species, and enhanced activity of antioxidant enzymes in tomato seedlings. Exogenous melatonin was also found to inhibit the expression of abscisic-acid-synthesis-related genes, resulting in a reduction in the abscisic acid content in tomato seedlings. Additionally, it significantly increased the root length, root surface area, and root vitality of the plants. When compared to drought treatment, tomato plants treated with melatonin exhibited a 61.92% increase in average yield and a 37.79% increase in fruit weight per plant. Furthermore, the organic acid content decreased by 23.77%, while soluble solids and sugars increased by 15.07% and 35.49%, respectively. These findings suggest that exogenous melatonin effectively alleviates the inhibition of photosynthesis and growth in tomato seedlings under drought stress. It achieves this by regulating the content of osmotic stress substances and the activity of antioxidant enzymes, thus enhancing the resistance of tomato seedlings to drought stress. Moreover, melatonin regulates root growth by mediating the biosynthesis of endogenous ABA, thereby improving the absorption and utilization efficiency of water and nutrients in plants. Consequently, it enhances tomato fruit yield and quality under drought stress.

Nutrients Use Efficiency in Coupled and Decoupled Aquaponic Systems

Aquaponics is currently undergoing a transformation into an intensive food production system. The initially applied systems focused on small-scale, fish-centric coupled (CAP, the aquaculture, and the hydroponic units are arranged in a single loop, and the water flows continuously from the fish tanks to the plant unit and back) aquaponics. More recently, the primary area of research interest has shifted toward larger-scale, plant-centric decoupled (aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently) systems, aiming to achieve greater economic benefits and employ more environmentally friendly practices. The objective of this study was to address gaps in the expansion of decoupled larger-scale aquaponics and to provide a comprehensive understanding of the water and nutrient flow in the system. For this purpose, experiments were performed in a greenhouse on CAP and DCAP systems, while this study also included measurements in a pure hydroponic system (HP). This study presents an assessment of the water and nutrient flow in four different crops: basil; cucumber; parsley; and tomato, all co-cultivated with a tilapia aquaculture system. Significant nutrient deficiencies and imbalances were identified in the CAP solution, leading to pronounced impacts on nutrient assimilation, particularly for fruiting vegetables. However, the average nutrient use efficiency (NUE) for nitrogen, phosphorous, potassium, and calcium was found to be 42% higher in the CAP treatment compared to HP and DCAP treatments. The nutrient solution in the DCAP treatment did not exhibit differences in water quality parameters and nutrient efficiency when compared to HP, resulting in similar effects on nutrient assimilation. Nonetheless, it was observed that DCAP plants exhibited superior NUE compared to HP plants.

Impact of feeding dried distillers' grains with solubles diet on microbiome and metabolome of ruminal and cecal contents in Guanling yellow cattle.

Dried distillers' grains with solubles (DDGS) are rich in nutrients, and partially alternative feeding of DDGS effectively reduces cost of feed and improves animals' growth. We used 16S rDNA gene sequencing and LC/MS-based metabolomics to explore the effect of feeding cattle with a basal diet (BD) and a Jiang-flavor DDGS diet (replaces 25% concentrate of the diet) on microbiome and metabolome of ruminal and cecal contents in Guanling yellow cattle. The results showed that the ruminal and cecal contents shared the same dominance of Bacteroidetes, Firmicutes and Proteobacteria in two groups. The ruminal dominant genera were Prevotella_1, Rikenellaceae_RC9_gut_group, and Ruminococcaceae_UCG-010; and the cecal dominant genera were Ruminococcaceae_UCG-005, Ruminococcaceae_UCG-010, and Rikenellaceae_RC9_gut_group. Linear discriminant analysis effect size analysis (LDA > 2, P < 0.05) revealed the significantly differential bacteria enriched in the DDGS group, including Ruminococcaceae_UCG_012, Prevotellaceae_UCG_004 and Anaerococcus in the ruminal contents, which was associated with degradation of plant polysaccharides. Besides, Anaerosporobacter, Anaerovibrio, and Caproiciproducens in the cecal contents were involved in fatty acid metabolism. Compared with the BD group, 20 significantly different metabolites obtained in the ruminal contents of DDGS group were down-regulated (P < 0.05), and based on them, 4 significantly different metabolic pathways (P < 0.05) were enriched including "Linoleic acid metabolism," "Biosynthesis of unsaturated fatty acids," "Taste transduction," and "Carbohydrate digestion and absorption." There were 65 significantly different metabolites (47 were upregulated, 18 were downregulated) in the cecal contents of DDGS group when compared with the BD group, and 4 significantly different metabolic pathways (P < 0.05) were enriched including "Longevity regulating pathway," "Bile secretion," "Choline metabolism in cancer," and "HIF-1 signaling pathway." Spearman analysis revealed close negative relationships between the top 20 significantly differential metabolites and Anaerococcus in the ruminal contents. Bacteria with high relevance to cecal differential metabolites were Erysipelotrichaceae_UCG-003, Dielma, and Solobacterium that affect specific metabolic pathways in cattle. Collectively, our results suggest that feeding cattle with a DDGS diet improves the microbial structure and the metabolic patterns of lipids and carbohydrates, thus contributing to the utilization efficiency of nutrients and physical health to some extent. Our findings will provide scientific reference for the utilization of DDGS as feed in cattle industry.

Smart Farming Tool for Monitoring Nutrients in Soil and Plants for Precise Fertilization

The current political, social, and economic conditions place, more than ever, the need to sustainably supply nutrients for plants, integrating low-impact, crop-adapted, variable-rate-application fertilizer solutions, at the center of attention. Fertilization plans should be based on the monitoring of soil fertility to address the proper rate of fertilizer application along with the development of techniques able to increase nutrient uptake efficiency. Monitoring and modelling analysis of the effects of agronomic management in different pedoclimatic conditions can provide several advantages, that include higher nutrient efficiency, increase in plant growth and yield, decreased fertilization costs, increased profit, reduced environmental impact. This approach should enter into a framework of precision farming methodologies for the distribution of nutrients adopted at different levels (region, farm, field, plot), to obtain the maximum efficiency of inputs.

Three environmental dimensions of beef cattle in tropical feedlot: Water, nutrients and land

This study aims to evaluate water, land, and nutrient efficiencies in a tropical beef feedlot system by providing artificial shading and considering local conditions and feed cultivation. The study was conducted at the Experimental Feedlot of Embrapa Southeast Livestock in Brazil. Forty-eight Nellore bulls were divided into two groups, with one group having shade (GS) and the other without shade (GWS). The animals' body weights, water intake, and dry matter intake were recorded. The water footprint was calculated using a product-focused assessment, considering water consumed in feed production and animal drinking. The nutrient balance and land footprint were also assessed. To both treatments, the crop scenario with soybean and corn first crop produced in Maringa resulted in the lowest water and land footprint values. Corn was the main contributor to green water consumption. The efficiency in water use for corn decreased between the first and second crops. The water footprint of soybean meal varied between production locations. GWS had slightly higher average blue water consumption than GS. In terms of nutrient balance, the GS treatment exhibited lower nitrogen and phosphorus balance values, indicating higher efficiency in the use of these elements. The provision of artificial shading was found to reduce the water footprint and improve nutrient use efficiency. The location of grain production and the timing of corn planting were identified as key factors influencing water and land footprint values.

The Mixture of Legumes and Gramineous as Green Manure and Its Effect on Nutrient Efficiency and Soil Solution Characteristics in Three Successive Crops

The Mixture of Legumes and Gramineous as Green Manure and Its Effect on Nutrient Efficiency and Soil Solution Characteristics in Three Successive Crops