Negative Nutrient Balance Research Articles

Integrated plant nutrient supply modules for enhancing crop growth, productivity and nutrient balance in maize - chickpea cropping sequence

A long-term field study was conducted to evaluate integrated plant nutrient supply (IPNS) system in maizechickpea cropping sequence. In this study, twelve IPNS modules of Soil Test Crop Response (STCR) based fertilizers, recommended dose of fertilizers (RDF), farmyard manure (FYM), poultry manure (PM), urban compost (UC), maize residue (MR) and Gliricidia loppings (GL) were investigated. Results indicated that plant height, dry biomass, yield parameters (cob length and girth, grains/cob and 1000-grains weight) and yields (grain and stover) of maize significantly (p=0.05) improved with IPNS module (75% NPK +5 t FYM) and increased 31.8 and 23.8% grain yield over the RDF and 100% NPK of STCR, respectively. In chickpea, the higher plant height, dry biomass, pods/ plant and yields (grain and straw) were obtained with the residual fertility of FYM @ 25 t/ha every year and followed by IPNS module (75%NPK +5 t FYM). However, residual fertility of PM and UC based IPNS modules also considerably improved the crop growth and yields of chickpea. Substantially higher system productivity was also noticed with 75% NPK +5 t FYM and followed 75% NPK +1 t PM based IPNS modules which was 1.86 and 0.99 t/ ha higher than RDF. A positive nutrient balance was recorded with addition of higher level FYM only (25 t/ha) Whereas, a negative nutrient balance was noticed for N and K in all plots excluding higher level of organic manures. However, there has been substantial build-up of N, P and K in plots receiving 25 t FYM every year. The additional supply of nutrients (organic + inorganic) is crucial for positive nutrients balance. Thus, STCR based fertilizers (75% NPK) along 25% nutrients through organic manures (FYM and PM) sustained the crop yield while the addition of FYM (25 t/ha) is essential for a positive balance of nutrients in the soil.

283 Awardee Talk: Effects of Late Gestational Maternal Nutrient Balance on Nutrient Partitioning to the Gravid Uterus in Beef Cattle

Abstract Successful intrauterine growth relies on adequate placental nutrient transfer capacity and is determined by placental size, placental morphology, uteroplacental blood supply, nutrient transporter abundance, and the nutrients available in maternal circulation. The majority of bovine fetal growth occurs during late gestation and must be accompanied by similar exponential increases in uteroplacental development to allow for necessary nutrient delivery. Competition for nutrients in young females between maternal growth and satisfying pregnancy, lactation, and maintenance requirements is still poorly understood. Our current work investigated the relationships between maternal, fetal, and uteroplacental factors and the impacts of late gestational nutrient restriction on prenatal nutrient delivery to the calf. Analysis of 113 full-term expelled placentas revealed that primiparous dams and dams in thin body condition had smaller placentas than their older or fleshier counterparts, suggesting the addition of growth requirements or exhausted nutrient reserves limited placental and fetal development. Calf size at birth and placental weight were positively correlated among all females, but it is still unknown which controls and signals for the growth of the other. Uterine blood flow measured during late gestation was positively correlated with calf birth weight; however, uterine blood flow and placental weight were only positively correlated closer to parturition at 40 and 20 d before calving. Additionally, contralateral uterine blood flow may have a disproportionately greater contribution to placental and fetal growth as it more closely resembled total blood flow associations than did ipsilateral. In 2 experiments, primiparous females fed 70% of energy and protein requirements during late gestation lost body weight and condition, had less metabolites in circulation, and had lower maternal heart rates than those fed to meet requirements. In Exp. 1, nutrient restricted dams had less contralateral placental growth, yet total uterine blood flow and placental weight were maintained and ensured fetal growth similar to control offspring. In Exp. 2, nutrient restriction reduced calf birth weight by 15%. Fetal growth perturbations were largely driven by a 17% reduction in placental size along with less nutrients available from maternal circulation, independent of a concomitant decrease in uterine blood flow. At 48 h of age, calf visceral organs were smaller due to nutrient restriction, but asymmetrical growth allowed for growth of the brain, lungs, and bone to be spared. Ongoing analysis of cotyledonary nutrient transporter and angiogenic factor gene expression will provide crucial insight into another determinant of placental nutrient transfer capacity. These findings demonstrate that pregnant beef females in a negative nutrient balance will attempt to spare fetal growth but at a certain threshold placental adaptation can be compromised, resulting in intrauterine growth restriction. A better understanding of nutrient delivery to the gravid uterus will allow for improved management strategies to ensure optimal fetal growth.

Postruminal choline supply during negative nutrient balance alters components of hepatic mTOR signaling and plasma amino acids in lactating Holstein cows

Choline requirements for dairy cattle are unknown. However, enhanced postruminal supply of choline may increase flux through the methionine cycle to spare Met for other functions such as protein synthesis and phosphatidylcholine (PC) synthesis during periods of negative nutrient balance (NNB). The objective was to investigate the effects of postruminal choline supply during a feed restriction-induced NNB on hepatic abundance and phosphorylation of mTOR (mechanistic target of rapamycin)-related signaling proteins, hepatic lipidome and plasma AA. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 DIM) were used in a replicated 5 × 5 Latin square design with 4 d of treatment and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements to induce NNB) with abomasal infusion of water (R0) or restriction plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected via biopsy on d 5 after infusions ended and used for Western blot analysis to measure proteins involved in mTOR signaling and untargeted lipidomics. Blood was collected on d 1 to 5 for plasma AA analysis. Statistical contrasts for protein and AA data were A0 versus R0 (CONT1), R0 versus the average of choline dose (CONT2) and tests of linear and quadratic effects of choline dose. Analysis of lipidomic data were performed with the web-based metabolomic processing tool MetaboAnalyst 5.0. Ratios of p-RPS6KB1:tRPS6KB1, p-EEF2:tEEF2, and p-EIF2:tEIF2 were greater with R (CONT1). Among those, supply of choline led to decreases in p-EEF2:tEEF2 (CONT2), p-EIF2:tEIF2 and tended to decrease p-EIF4BP1:tEIF4BP1. However, the effect was quadratic only for p-EEF2:tEEF2 and p-EIF2A:tEIF2A, reaching a nadir at 6.25 to 12.5 g/d choline ion. The ratio of p-RPS6KB1:tRPS6KB1 was not affected by supply of choline and was close to 2-fold greater at 25 g/d choline versus A0. Plasma Met concentration decreased with R (CONT1), but increased linearly with choline. Restriction also increased plasma 3-methyl-histidine (CONT1). The partial least squares discriminant analysis model of liver lipids distinguished treatments, with 13.4% of lipids being modified by treatment. One-way ANOVA identified 109 lipids with a false discovery rate ≤0.05. The largest group identified was PC species; all 35 detected decreased with R versus A0, but there were few differences among choline treatments. Overall, data suggested that dephosphorylation of EEF2 and EIF2A due to enhanced choline supply potentially helped maintain or increase protein synthesis during NNB. While activation of mTOR was not altered by choline, this idea of increased protein synthesis is partly supported by the increased circulating Met. However, enhanced postruminal choline had limited effects on the species of lipid produced during a period of NNB.

Influence of farmers’ socio-economic characteristics on nutrient flow and implications for system sustainability in smallholdings: a review

The rise in global human population, coupled with the effects of climate change, has increased the demand for arable land. Soil fertility has been the most affected, among other things. Many approaches to soil fertility management have been proposed by studies in Sub-Saharan Africa (SSA); however, the question of sustainability remains. Nutrient monitoring (NUTMON), which combines biophysical and socio-economic features for soil fertility management, gives an in-situ soil fertility status of a given land use system, which ultimately provides guidance in proposing appropriate soil management techniques in a given land use system. In this review, the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) approach was deployed for a systematic search of the literature materials. The review evaluated various studies on nutrient monitoring in SSA soils in order to understand the socioeconomic attributes and their influence on farming systems, as well as nutrient flow and balances. The review identified two dominant smallholder farming systems in SSA: mixed crop-livestock and mixed crop farming systems. Also, this review revealed that most nutrient balance studies in SSA have been done in mixed crop and livestock farming systems. However, regardless of the farming systems, the overall mean nutrient balances in all studies, particularly those of nitrogen (N) and potassium (K), were negative, indicating significant nutrient mining. The review further revealed a vast range of biophysical soil fertility management technologies; however, their adoption has been limited by socio-economic aspects including land ownership, gender, financial position, literacy level, and access to inputs. Therefore, in view of this situation, integrating biophysical and socioeconomic disciplines could address the problem of soil nutrient depletion holistically, thus decreasing the existing negative nutrient balances in the SSA region.

Understanding the Dynamics of Soil Nutrient Balance and Its Management Option of a Common Bean Farm: The Case of West Arsi, Ethiopia

The yield of Common bean (Phaseolus vulgaris), the important legume crop for large percentage of the world's population is challenged by soil fertility declining in the most growing regions. The survey was conducted in Goto Onomo kebele, West Arsi Zone, Ethiopia during June 15, 2017 to understand the dynamic of soil nutrient balance in common bean farm and its management option. The Combinations of field observation and semi-structure interview data collection methods and NUTMON (nutrient monitoring for tropical farming systems) method of FAO data analysis in micro level approach were applied. Accordingly, a total of 10kg/day of cow dung was recorded. Total inputs of 45.75kg/season was recorded as Nitrogen sources from different inputs. Additionally, 48.83kg/season of nutrient out flow was recorded. As a result, negative nutrient balance (-3.08kg/season) was exhibited due to the high nutrient removal rates by harvested biomass that leads to poor nutrient management and low use efficiency. Hence, the farm has been exposed for nutrient deficiency by -3.08kg/season that farm level nutrient management such as crop residue management, addition of farmyard manure, and inorganic fertilizer sources are recommended as better alternative management options for legume crop production. Keywords: Common bean, Goto Onomo, nutrient balance, West Arsi DOI: 10.7176/JBAH/12-13-01 Publication date: July 31 st 2022

Blood and adipose tissue steroid metabolomics and mRNA expression of steroidogenic enzymes in periparturient dairy cows differing in body condition

In high-yielding dairy cows, the rapidly increasing milk production after parturition can result in a negative nutrient balance, since feed intake is insufficient to cover the needs for lactation. Mobilizing body reserves, mainly adipose tissue (AT), might affect steroid metabolism. We hypothesized, that cows differing in the extent of periparturient lipomobilization, will have divergent steroid profiles measured in serum and subcutaneous (sc)AT by a targeted metabolomics approach and steroidogenic enzyme profiles in scAT and liver. Fifteen weeks antepartum, 38 multiparous Holstein cows were allocated to a high (HBCS) or normal body condition (NBCS) group fed differently until week 7 antepartum to either increase (HBCS BCS: 3.8 ± 0.1 and BFT: 2.0 ± 0.1 cm; mean ± SEM) or maintain BCS (NBCS BCS: 3.0 ± 0.1 and BFT: 0.9 ± 0.1 cm). Blood samples, liver, and scAT biopsies were collected at week −7, 1, 3, and 12 relative to parturition. Greater serum concentrations of progesterone, androsterone, and aldosterone in HBCS compared to NBCS cows after parturition, might be attributed to the increased mobilization of AT. Greater glucocorticoid concentrations in scAT after parturition in NBCS cows might either influence local lipogenesis by differentiation of preadipocytes into mature adipocytes and/or inflammatory response.

186 Young Scholar Presentation: Immunometabolism during periods of negative nutrient balance or heat stress is altered by dietary methyl donor supply in dairy cows

Abstract Our research examined the effects of enhancing methyl donor supply on immunometabolism during periods of negative nutrient balance (NNB) or heat stress (HS). The first experiment examined the effects of post-ruminal choline supply during NNB on production and pathways of 1-carbon metabolism. Ten primiparous rumen-cannulated cows (158±24 DIM) were used in a replicated 5×5 Latin square design with 4d treatment periods and 10d of recovery. Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements) with abomasal infusion of water or R plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected at the end of each treatment period. Enhancing choline supply increased milk yields, but decreased liver triacylglycerol. Activity of betaine homocysteine methyltransferase increased with choline, while methionine synthase tended to increase, and cystathionine β-synthase was decreased. These changes were associated with increased liver and plasma Met. Overall, enhanced supply of choline during NNB increases flux through the Met cycle to regenerate Met and reduce liver triacylglycerol. The second experiment examined the effects of rumen-protected Met (RPM) during HS on mTOR (mechanistic target of rapamycin)-related signaling proteins in the mammary gland. Thirty-two multiparous cows (184±59 DIM) were assigned to an environmental treatment, and a dietary treatment [TMR with RPM (0.105% DM) or without (CON)] in a crossover design. There were 2 periods with 2 phases per period. In phase 1 (9d), all cows were in thermoneutral conditions (TN) and fed ad libitum. During phase 2 (9d), group 1 (n=16) was exposed to HS using electric heat blankets while group 2 (n=16) remained in TN but were pair-fed to HS counterparts. After a washout period (21d), the study was repeated (period 2), with environmental treatments being inverted and dietary treatments remaining the same. Mammary tissue was collected at the end of phase 2. Abundance of phosphorylated mTOR was greater with RPM and tended to be greater with HS. Control cows had a greater decrease in milk protein (%) during phase 2 (difference from phase 1) compared with RPM cows, suggesting that RPM supplementation during HS may support greater milk protein synthesis via mTOR activation. The third experiment investigated the effects of RPM during HS on the response of mammary gland explants to lipopolysaccharide (LPS). Twenty-five mg of tissue obtained from cows in the second experiment was incubated with 0 or 3 μg/mL of LPS for 2h. Incubation with LPS increased abundance of genes associated with inflammation, while HS decreased genes associated with antioxidant responses. Expression of NFKB1was greater in LPS-treated explants from non-HS compared with HS cows. These data indicate that HS reduced immune and antioxidant responses while RPM did not attenuate the inflammatory response induced by LPS in vitro. Overall, data indicated a beneficial effect of choline during NNB and Met during HS on immunometabolism in dairy cows.

112 Young Scholar Presentation: Protein and Amino Acid Nutrition in Fresh Cows

Abstract During the 4 weeks after parturition, postpartum dairy cows (i.e., fresh cows) have the highest risk of disease and metabolic disorders. This is largely because nutrient requirements for lactation outweigh the cow’s metabolizable intake. As a result, cows enter negative nutrient balances and mobilize endogenous protein and energy stores to meet demands. Although negative energy balance, in terms of mass, is more negative than protein balances over this time frame, intake of metabolize protein (MP) and its amino acid (AA) profile may influence the performance and health of fresh cows more than increasing energy intake. Better performance from greater MP and AA supplies may also carry over and enhance milk production further into lactation. In our recent experiment, increasing MP supplies to fresh cows by feeding a greater rumen undegradable protein concentration (RUP; 7 vs 10% of DM) also increased milk and milk component yields. However, when the AA profile of the supplemental RUP was optimized to mimic the AA profile of casein, the greater yields were sustained much further into lactation. This may be because fresh cows fed the “casein like AA profile” had improved health and less body protein catabolism than cows fed a similar MP concentration. However, production responses with a greater MP intake depended on what the RUP replaced in the diet and on parity. When replacing forage fiber with RUP instead of nonforage fiber, multiparous cows had a reduction in milk and milk fat yields whereas primiparous cows performed similarly regardless of what type fiber was replaced. This suggested reducing forage fiber in a high MP diet will not increase overall MP intake, and multiparous cows may require more forage fiber during the fresh period than primiparous cows. Overall, MP intake and the AA supply is important for the health and production of fresh cows.

Nutrient Balance of Farming Systems in Tigray, Northern Ethiopia

The purpose of this study was to explore how soil fertility management and farm nutrient balances varied across socio-economic groups in northern Ethiopia. Field surveys were carried out in 32 farms in Tigray, northern Ethiopia using different socio-economic groups, viz.: model/non model and female/male farmers. The nutrient input flows and output flows were monitored and analysed using Monitoring for Quality Improvement (MonQI) toolbox. Results of the study showed that average nitrogen (N), phosphorus (P) and potassium (K) balances in the highlands were − 30.8, 4.08 and − 42.75 kg ha−1, respectively while in the lowland the average nutrient balance were − 19.5, 2.09 and − 15.35 kg ha−1 for N, P and K, respectively. All farms had negative N and K nutrient balances, with lower negative N and K balance recorded in highlands than the lowlands. The reported values account about 0.6% and 2.7% of the total soil N and K pools in the highland and 0.3% and 0.8% in the lowland, respectively. Nutrient depletion rates in the highlands were 0.6% year−1 and 2.7% year−1 for N and K, respectively while for the lowlands the rates were 1.5% year−1 and 3.4% year−1 for N and K, respectively. Depletion rates were higher in the lowlands than highlands due to monocropping, crop residue removal and absence of soil water conservation. Most farms belonging to model farmers of both categories and non-model male farmers show more negative nutrient balance. We conclude that socio-economic status and being model farmers had less role in soil fertility maintenance. However, the more positive balance in female-headed households points to the need for adequate attention and support for the female-headed households. This study underscores the need for sustainable nutrient management. More so, agricultural policy should target female-headed households to help reduce the productivity gap between male-headed households and female-headed households.

Quantification of Soil N, P and K Balance In Peat Soils: Influence of Fluctuating Water Table

This study intends to develop the soil N, P and K balance in peat soils by quantifying the input, internal flow and output of the nutrients under different water table conditions, with and without the pineapple crops uptake. The soil samples for each water table conditions were analyzed for total-N, mineral-N, available-P and exchangeable K. Results showed that pineapple of the variety Moris requires high input of N and K compare to P. Without crops uptake, all treatments indicate positive soil nutrient balance where the treatment with fluctuating water table between 40-80 cm depth showed highest positive balances. In contrast, negative nutrient balance occurred in the presence of uptake by pineapple, where treatment with fluctuating water table between 0-40 cm recorded the highest nutrient deficiency. It is suggested that fluctuating water table influence the soil nutrient dynamics and soil nutrient balance and in this case act as the main pathways of nutrient loss through leaching.

THE IMPACT OF AGRICULTURAL ACTIVITY ON THE BALANCE OF NUTRITIONAL SUBSTANCES IN SOILS OF ZHYTOMIR REGION

It is known that in Ukraine agriculture is much more developed than industry. This is due to the presence in our country of high-yielding lands, in particular, the black earth, which is a national wealth and protected by the constitution of Ukraine. This is what determines Ukraine’s belonging to the agrarian states of the world. As a result, the level of land plowing in our country is quite high, and the acreage occupies a considerable share of agricultural land. On the other hand, intensive involvement of land in the production of agricultural products leads to a deterioration of the soil condition, reducing their natural fertility. The lack of tight control by the state on the use of land by producers only exacerbates the effects of anthropogenic impact on soil quality. The Zhytomyr region is located in the Polissya and Forest-Steppe zones. The predominant soil type in its territory is sod-podzolic (more than 60.0%), with humus content up to 1.5%. Such soils are typical of northern part of the region. The forest-steppe part of Zhytomyr region is characterized by more fertile soils with humus content of more than 2.5%. The acreage of Zhytomyr region is 648,1 thousand hectares. Agricultural enterprises mainly have a grain direction, since in the structure of acreage the major part is occupied by grain and legumes, corn for grain, sunflower, soybean and rapeseed. The areas with the highest share of arable land are Andrushivskiy, Berdychivskiy, Ruzhinskiy, Popilnyanskiy, Chudnivskiy, Chernyakhivskiy and Brusylivskiy, with an area of arable land 38.2–53.6% of the total area of the district. Minerals and organic fertilizers are not sufficiently used in the agricultural system of the region. This is evidenced by the negative nutrient balance, which amounts to 35.5 tonnes from the entire acreage. With regard to mineral fertilizers, it is used more intensively by producers than organic fertilizers cultures. Fertilized areas in the sections of Zhytomyr region are shown on the corresponding map diagrams. According to our research, Chudnivskiy (2.54%), Andrushivskiy (2.62%), Zhytomyrskiy (2.63%) and Ruzhynskiy (2.9%) regions have the highest weighted average humus. It is in this area that land use can be considered environmentally sound. In total, 838888 tones of humus were formed in the area under crops at an area of 607.1 thousand hectares. However, the main share in the process of humification is plant residues, not organic fertilizers. Therefore, the low level of fertilizer use by agricultural enterprises causes a shortage of nutrients in the soil of the acreage and indicates the irrational use of land in agricultural production.

Choline supply during negative nutrient balance alters hepatic cystathionine β-synthase, intermediates of the methionine cycle and transsulfuration pathway, and liver function in Holstein cows

Although choline requirements for cows are unknown, enhanced postruminal supply may decrease liver triacylglycerol and increase flux through the Met cycle to improve immunometabolic status during a negative nutrient balance (NNB). Our objectives were to investigate the effects of postruminal choline supply during a feed restriction-induced NNB on (1) hepatic activity cystathionine β-synthase and transcription of enzymes in the transsulfuration pathway and Met cycle; (2) hepatic metabolites in the Met cycle and the transsulfuration pathway, bile acids, and energy metabolism; and 3) plasma biomarkers of liver function, inflammation, and oxidative stress. Ten primiparous rumen-cannulated Holstein cows (158 ± 24 d postpartum) were used in a replicated 5 × 5 Latin square design with 4-d treatment periods and 10 d of recovery (14 d/period). Treatments were unrestricted intake with abomasal infusion of water, restricted intake (R; 60% of net energy for lactation requirements) with abomasal infusion of water, or R plus abomasal infusion of 6.25, 12.5, or 25 g/d choline ion. Liver tissue was collected on d 5 after infusions ended, and blood was collected on d 1, 3, and 5. Statistical contrasts were A0 versus R0 (CONT1), R versus the average of choline doses (CONT2), and tests of linear and quadratic effects of choline dose. Activity of cystathionine β-synthase was lower with R (CONT1) and decreased linearly with choline. Hepatic glutathione was not different with R or choline, but taurine tended to be greater with choline (CONT2). Betaine and carnitine were greater with R (CONT1) and further increased with choline (CONT2). Concentrations of NAD+ were greater with choline (CONT2). Cholic and glycol-chenodeoxycholic acids were decreased by R and choline, while taurocholic and tauro-chenodeoxycholic acids were not altered. Plasma aspartate aminotransferase and bilirubin were greater with R (CONT1) but decreased with choline (CONT2). Paraoxonase was lower with R and increased with choline (CONT2). Data suggest that enhanced supply of choline during NNB decreases entry of homocysteine to the transsulfuration pathway, potentially favoring remethylation to Met by acquiring a methyl group from betaine. As such, Met may provide methyl groups for synthesis of carnitine. Along with production data indicating that 12.5 g/d choline ion improved milk yield and liver fatty acid metabolism during NNB, the changes in blood biomarkers also suggest a beneficial effect of choline supply on liver function and oxidative stress.

Rice-Residue Management Practices of Smallholder Farms in Vietnam and Their Effects on Nutrient Fluxes in the Soil-Plant System

In Vietnam, approximately 39 million tons of rice (Oryza sativa) residues accrue every year. In this study, we quantified soil nutrient balances of paddy rice fields under different crop-residue management practices in northern Vietnam. On twelve farms, we calculated nutrient balances for the four prevalent rice-residue management practices, i.e., (1) direct incorporation of rice residues into the soil, (2) application of rice-residue compost, (3) burning of rice residues on the field, and (4) the use of rice residues as fodder for livestock. Soils under practices (1) to (3) showed a positive nutrient balance, which indicates that soil fertility can be maintained under these practices and that the amounts of chemical fertilizers can be considerably reduced. If not, there is a risk of eutrophication in the surrounding surface waterbodies. Practice (4), in contrast, resulted in a negative nutrient balance, which indicates the need for returning nutrients to the soils. From our findings we conclude that knowledge about the effects of rice-residue management practices on nutrient cycles may help to optimize the use of fertilizers, resulting in a more sustainable form of agriculture.

Phosphorus mobilization in low-P arable soils may involve soil organic C depletion

Organic farming systems often show negative nutrient balances that may compromise the availability of phosphorus over the mid-term. Calcareous soils with low organic matter generally show low or very low phosphorus availability. Under these conditions, P retained in soil organo-mineral complexes -either in organic or inorganic forms-after its solubilization and -in the case of organic P compounds-subsequent mineralization may be a source of P to plants and soil organisms. By studying the changes in soil retained and soluble P pooloccurring during the growth of two legumes in two scenarios of contrasting P availability we aimed to describe the release of soil retained P, organic and inorganic, into the soluble pools and to relate it to changes in organic C during crop growth.The experimental design was a split-plot of two nearby fields with contrasting P availability. In each field, two species of legumes, chickpea and bitter vetch, were planted and manure was added in alternating plots. During the legume growth we monitored soil P by analyzing soluble inorganic and organic P (NaHCO3-Pi and NaHCO3-Po), the soil retained inorganic and organic P pools (H2SO4-P before and after ashing), and acid and alkaline phosphatase activities in each plot at sowing time and at the late flowering stage.All P forms were higher in the high-P field than in the low-P field, except for soluble Po, which was higher in the low-P field at sowing time. In the high-P field during legume growth we detected an increase of the soluble Po and soluble Pi pools and of the soil retained Po that may have originated from a reduction of the soil retained Pi pool. In contrast, in the low-P field, the decrease of the soil retained Pi pool coincided with a decrease of the soluble Po pool, while the soil retained Po did not show any significant change. In low-P soils, the soil retained Po pool appeared to be the main source of soluble Pi. Changes in the soil retained Pi pool during legume growth occurred in all soils and were much larger than the amount of P required by plants. Likewise, the most likely P transformations in our soils involved changes between inorganic and organic forms suggesting that these changes were mainly mediated by soil microbiota. P transformations in low-P soils reduced soil organic C and the C/Po ratio, thus suggesting that crops growing in low-P soils may deplete organic matter from protected mineral-organic associations in low organic matter arable soils likely by promoting organic acid exudation by roots and soil microbiota.

Defining malnutrition: A plea to rethink

In a recent consensus report in Clinical Nutrition the undernourished category of malnutrition was proposed to be defined and diagnosed on the basis of a low BMI or unintentional weight loss combined with low BMI or FFMI with certain cut off points. The definition was endorsed by ESPEN despite recent endorsement of a very different definition. The approach aims to assess whether nutritional intake is sufficient but is imprecise because a low BMI does not always indicate malnutrition and individuals with increasing BMI's may have decreasing FFM's. The pathophysiology of individuals, considered to be malnourished in rich countries and in areas with endemic malnutrition, results predominantly from deficient nutrition combined with infection/inflammation. Both elements jointly determine body composition and function and consequently outcome of disease, trauma or treatment. When following the consensus statement only an imprecise estimate is acquired of nutritional intake without knowing the impact of inflammation. Most importantly, functional abilities are not assessed. Consequently it will remain uncertain how well the individual can overcome stressful events, what the causes are of dysfunction, how to set priorities for treatment and how to predict the effect of nutritional support. We therefore advise to consider the pathophysiology of malnourished individuals leading to inclusion of the following elements in the definition of malnutrition: a disordered nutritional state resulting from a combination of inflammation and a negative nutrient balance, leading to changes in body composition, function and outcome. A precise diagnosis of malnutrition should be based on assessment of these elements.

Post-partum serum albumin as a predictor of metritis

The transition cow is in a negative nutrient balance, recognized largely as a negative energy and calcium balance. In response to the negative energy state, the body begins to mobilize body fat. In response to the negative calcium balance, the body begins to mobilize calcium stores from bone. A negative protein balance has also been documented, and results in mobilization of protein reserves from skeletal muscles. Total serum protein has been associated with cow health, but serum albumin is more specific and plays an important role in transporting triglycerides and calcium. Albumin has been proposed as a potential biomarker for health in the transition cow. The objective of this study was to determine whether low serum albumin concentrations 2 days after calving would result in an increased risk of developing acute puerperal metritis (APM). A secondary objective was to establish whether total or ionized calcium levels 48 hours post calving were associated with serum albumin levels early postpartum.

Aspects and mechanisms of low fertility in anovulatory dairy cows

Postpartum anovulation is a natural process that is observed in most mammals, including women. In lactating dairy cows, the interval from calving to first ovulation typically averages 4 to 5 weeks, but a substantial proportion of cows have not resumed estrous cyclicity by 60 days postpartum. Extended delay in resumption of first postpartum ovulation is known to exert long-lasting detrimental effects on fertility in dairy cows including the lack of spontaneous estrus and subsequent timely insemination postpartum, but when anovular cows have the estrous cycle synchronized for artificial insemination (AI), still pregnancy per AI is reduced and the risk of pregnancy loss increased. Many risk factors exist for extended postpartum anovulatory periods such as negative nutrient balance and diseases, and these risk factors are also known to depress fertility by themselves. A key feature in anovular cows when inseminated is that they develop the ovulatory follicle under subluteal or low concentrations of progesterone. Progesterone from the corpus luteum is pivotal for follicle development, oocyte competence, embryo growth, and endometrial function; however, many of these effects exerted by progesterone are mediated either by secretion of gonadotropins influencing follicular function and oocyte competence or by endometrial histotroph secretion influencing embryo/conceptus growth and developmental biology. Sub-optimal concentrations of progesterone during follicle growth in anovular cows affect morula and early blastocyst quality, alter conceptus gene expression and affect endometrial function increasing the synthesis of prostaglandin F2α. When anovular cows receive sufficient supplemental progesterone during the antral stages of development of the ovulatory follicle, then pregnancy per AI is reestablished and resembled that of estrous cyclic cows that developed the follicle during diestrus. Preliminary data suggest that a minimum concentration of progesterone during follicle growth is needed to optimize fertility in anovular cows, at least 2.0 ng/ml.

Delicate Artistic Cereal Provision to Reduce Negative Nutrient Balance and Improve Dairy Cow Health

This article introduces a pragmatic approach of delicate cereal grain feeding to improve high-merit cow health in modern dairy farms. Meticulous inclusion of moderate amount of wheat and barley grains along with corn or sorghum grain has the capacity to moderately manipulate milk fat. This manipulation attempts to reduce the intense pressure on high-producing cows in meeting increased nutrient requirements. As a result of attenuated negative energy balance, liver and splanchnic metabolism and cow's systemic immunity can improve.

Agronomic survey to assess crop yield, controlling factors and management implications: a case-study of Babati in northern Tanzania

Improved agronomic management is important to reduce yield gaps and enhance food security in sub-Saharan Africa. This study was undertaken to understand contributing factors to observed yield gaps for maize in farmer fields and to demonstrate appropriate agronomic survey methods. The study aimed to (1) demonstrate an approach for farm-level agronomic survey, (2) identify key crop production constraints and (3) define the nutrient input and output balances of different fields. Agronomic survey was conducted in 117 farmer fields randomly distributed in a 10 km by 10 km block in Babati, northern Tanzania. A semi-structured questionnaire and production measurements were used to collect data which were analyzed with regression classification and mixed effect models. The exploitable maize yield gap at farm-level reaches up to 7.4 t ha−1, and only <5 % of fields achieve maize grain yield of 5 t ha−1. Slope, plant density, distance from homestead, crop variety, timing of planting and period since conversion significantly influenced maize yields. For example, fields on flat land had up to 1.6 t ha−1 more maize grain yield than those on steep slopes while fields with plant density >24,000 plants ha−1 had 900 kg ha−1 more yield than those with less density. At least 52 % of the fields had negative nutrient balances. We conclude that cropping systems used in Babati should be preferentially supplemented with mineral fertilizers while optimizing plant density, increasing manure application and appropriate varietal choice in order to reduce the yield gaps.

Carbon and nutrient fluxes and balances in Nuba Mountains homegardens, Sudan

Management intensification has raised concerns about the sustainability of homegardens in the Nuba Mountains, Sudan. This study aimed at assessing the sustainability of these agroecosystems following the approach of carbon (C) and nutrient balances. Three traditional (low input) and three intensified (high input) homegardens were selected for monitoring of relevant input and output fluxes of C, nitrogen (N), phosphorus (P) and potassium (K). The fluxes comprised those related to management activities (soil amendments, irrigation, and biomass removal) as well as estimates of biological N2 fixation, C fixation by photosynthesis, wet and dry deposition, gaseous emission, and leaching. Annual balances for C and nutrients amounted to −21 kg C ha−1, −70 kg N ha−1, 9 kg P ha−1 and −117 kg K ha−1 in high input homegardens and to −1,722 kg C ha−1, −167 kg N ha−1, −9 kg P ha−1 and −74 kg K ha−1 in low input homegardens. Photosynthesis C was the main C input flux with averaged of 7,047 and 5,610 kg C ha−1 a−1 in high and low input systems, respectively. Biological N2 fixation (17 kg N ha−1 a−1) was relevant only in low input systems. In both systems, the annual input of 77 kg K ha−1 through dust was highly significant and annual gaseous C losses of about 5,900 kg C ha−1 were the main C loss. In both garden types, the removal of biomass accounted for more than half of total nutrient exports of which one-third resulted from weeding and removal of plant residues and two-third from harvest. The observed negative nutrient balances may lead to a long-term decline of crop yields. Among other measures the reuse of C and nutrients in biomass removals during the cleaning of homegardens may allow to partially close C and nutrient cycles.