Evaluating the Impact of Crop Layout Changes on N and P Nutrient Balance: A Case Study in the West Liaohe River Basin, China

Regional crop layout has changed significantly due to climate, policy, and other factors, which has impacted farmland nutrient balance. Here, we evaluated the impact of crop layout changes on N and P nutrient balance in the West Liaohe River Basin from 2000–2015. The study area has long been in a N and P surplus state. The unit N surplus exhibited a downward trend and the unit P surplus showed an increasing trend. Significant correlations existed between planting areas and nutrient surplus. The N and P surplus layout was mainly concentrated in the West Liaohe River lower reaches basin. The planting area of wheat must be reduced and the areas of maize and soybean must be controlled to adjust the N and P balance and reduce the environmental pollution risk. Chemical fertilizer and seed inputs are the main sources of N input. Furthermore, combining farming and pastoral farming is conducive to improving N and P use efficiency. Manure can be absorbed by farmland, the ratio of organic and chemical fertilizers can be reasonably set, and chemical fertilizer application can be reduced.

Changes in Crop Layout, Effects on Farmland Nutrient Balance: A Case Study in The West Liaohe River Basin, China

Estimating regional soils Nitrogen and phosphorus balance in cropland is essential to improve management practices, reduce environmental risks and develop sustainable agriculture. In this study,spatial and temporal variations in crop layout, the impact on soil N and P nutrient balance were assessed from 2000 to 2015 in the West Liaohe River Basin between 2000 and 2015. The result shows that the area of cropland is on the rise, and the spatial distribution of arable land is consistent with the distribution of the main tributaries of the West Liaohe River basin. The change in planting layout for maize and soybeans has a significant impact on the nutrient balance of farmland, which plays a critical role in modifying surplus nutrients. Nutrient surpluses on farmland were mostly concentrated in areas where maize planting layout changed between 2000 and 2015. The N nutrient surplus rate decreased by 39.3%, N utilization efficiency, increased by 70.7%; P nutrient surplus rate decreased by 3.8%, and P utilization efficiency increased by 49.3%. The average utilization efficiencies of N and P nutrients were 27.8% and 9.1%, respectively, and the utilization efficiency was low. Chemical manure is the main source of nutrients. The risk of phosphorus pollution was higher than the risk of nitrogen pollution in the West Liaohe River Basin. The lower Liaohe River Basin (below the Sujiapu) was the region with the most violent changes in nitrogen and phosphorus nutrient balance. It is recommended that reduce the amount of chemical fertilizer application, especially, reduce the amount of P application, improve the ef-ficiency of nutrient use, and focus on strengthening pollution control in key areas such as the West Liaohe River lower reaches basin (below Sujiabao), reducing the risk of agricultural nonpoint source pollution.

Süt Sığırcılığı İşletmelerinde Ahır Gübresi Kullanımının ve Yönetiminin Ekonomik Analizi: Burdur İli Örneği

The objective of research was to economic analysis of manure utilization for fertilizer and manure management practices at the different size dairy farms engaged also in crop production in Burdur province. Data were obtained by conducting a questionnaire with 102 farmers which had dairy and crop productions. It was determined that as farm size increased ratio of crop nutrient demand met by manure increased. Crop nutrient demand met by manure was 29.9, 58.9 and 45.2 % for Group I, II and all farms average, respectively. When farmers used manure as fertilizer, amount of saving were 51.8, 107.1 and 80.6 TL/decare for Group I, II and all farms average, respectively. These results indicate that manure use can become economical for farmers. However, it has been found that nutrient losses are related to the excess in use of chemical fertilizers in all farms. Nutrient surplus due to extra chemical fertilizer use were 7.1, 15.9 and 11.8 kg for Group I, II and all farms average, respectively. Economic losses due to surplus nutrient substances usage were 65.1, 152.6 and 110.6 TL for Group I, II and all farms average, respectively. It was determined that farmers' knowledge level on manure use, management and chemical fertilizer were low in the research area. One major issue to be solved before manure use is to inform farmers about the importance of soil testing.

Using hillslope-scale groundwater model to bridge the gap between basin inputs and river concentrations. The case of nitrates in Brittany (France).

<p>Over the past decades, intensive agriculture has altered surface water and groundwater resources quality. Nutrient surplus increased nitrate concentrations in groundwater and rivers resulting in eutrophication or drinking water risk having ecosystem, sanitary and economic repercussions. Legislations led to a reduction of agricultural inputs of nitrogen since 1990’s followed by a decrease of nitrate concentrations in rivers, but still difficult to predict and evaluate. Indeed, the incomplete knowledge of the spatial variability of climate and nitrogen inputs, cumulated to the unknown groundwater heterogeneity,  leads to hydrological and biogeochemical processes difficult to model. This study deals with the long-term variations (~decades) of nitrate concentrations in three rivers (~30 km² catchment) located in Brittany. Thus, we focus on groundwater modelling because they constitute the bigger hydrological reservoir. We developed a parsimonious equivalent hillslope-scale groundwater model. The model parameterization, which controls hydrological functioning such as mean groundwater residence times, young water contribution to the river or denitrification, relies on long-term monitored streamflow and nitrate river concentrations. In addition, dissolved CFC were sampled in the catchments. Finally, we found that uncertainty on simulated nitrate river concentrations is low. The physically-based model also brings information on temporal and spatial variability of groundwater residence times highlighting the relative importance of young (1-5 yr) and old waters (~decades) for nitrate river concentrations. Moreover, calibrated models show similar trends looking at two fictive input scenarios from 2015 to 2050.</p>

Nutrient Budgeting of Primary Nutrients and Their Use Efficiency in India

The imbalanced use of fertilizers in India is evident from the fact that the current ratio of nitrogen, phosphorus and potassium in agricultural soil in several states is skewed towards nitrogen. This imbalance causes problems, right from stagnating or declining productivity to soil sickness, widespread deficiency of macro nutrients and micronutrients, and soil alkalinity and salinity. Eventually, it results in reduced efficiency of fertilisers, low yields and low profitability for farmers. Also, nitrogen pollution of surface and groundwater due to excessive fertiliser use has reached alarming levels in several states. Chemical fertilizers are currently the major emitters of nitrous oxide gas, a potent greenhouse gas and ozone depleting substance. Nutrient budget is an important tool to provide an early indication of potential problems arising from nutrient surplus and nutrient deficit. Balanced use of all types of fertilizers, including traditional organic manures and biofertilizers are needed to bring about a change in the prevailing regime that encourages excessive use of chemical fertilizers. However, meeting future food security targets in an over-populated developing country like India, needs to increase the nutrient use efficiency. This ultimately leads to site-specific need-based nutrient application and minimizing nutrient losses from fields. This leads to the 4R Nutrient Stewardship concept, applying the Right Source of nutrients, at the Right Rate, at the Right Time and in the Right Place. This paper provides a historical overview of the nutrient budgeting efforts and systematically reviews major challenges, opportunities, in defining, quantifying, and applying nutrient budgets and improving nutrient use efficiency.

Adipokines set neural tone by regulating synapse number

SummaryEnergy sensing neural circuits decide to expend or conserve resources by integrating tonic steady-state energy store information with phasic signals for hunger and food intake. Tonic signals, in the form of adipose tissue-derived adipokines, set the baseline level of energy-sensing neuron activity, providing context for interpretation of phasic messages. However, the mechanism by which tonic adipokine information establishes baseline neuronal function is unclear. Here we show that Upd2, a Drosophila Leptin ortholog, regulates actin-based synapse reorganization by reducing inhibitory synaptic contacts, thereby providing a permissive neural tone for insulin release under conditions of nutrient surplus. Unexpectedly, Insulin acts on the same upstream inhibitory neurons to conversely increase synapse number, hence re-instating negative tone. Our results suggest that two surplus-sensing hormonal systems, Leptin/Upd2 and Insulin, converge on a neuronal circuit with opposing outcomes that establish tonic, energy-store-dependent neuron activity.HighlightsThe adipokine Upd2 regulates number of inhibitory synaptic contacts on Insulin neurons.Upd2 activates an actin-regulating complex of Arouser, Basigin, and Gelsolin in target neurons.Arouser, Basigin, and Gelsolin reduce the extent of inhibitory contact on Insulin neurons.Insulin resets negative tone by increasing the number of synaptic contacts made by its own upstream inhibitory neurons.

Early podocyte injury and elevated levels of urinary podocyte-derived extracellular vesicles in swine with metabolic syndrome: role of podocyte mitochondria

Metabolic syndrome (MetS) is associated with nutrient surplus and kidney hyperfiltration, accelerating chronic renal failure. The potential involvement of podocyte damage in early MetS remains unclear. Mitochondrial dysfunction is an important determinant of renal damage, but whether it contributes to MetS-related podocyte injury remains unknown. Domestic pigs were studied after 16 wk of diet-induced MetS, MetS treated with the mitochondria-targeted peptide elamipretide (ELAM; 0.1 mg·kg−1·day−1 sc) for the last month of diet, and lean controls ( n = 6 pigs/group). Glomerular filtration rate (GFR) and renal blood flow (RBF) were measured using multidetector computed tomography, and podocyte and mitochondrial injury were measured by light and electron microscopy. Urinary levels of podocyte-derived extracellular vesicles (pEVs; nephrin positive/podocalyxin positive) were characterized by flow cytometry. Body weight, blood pressure, RBF, and GFR were elevated in MetS. Glomerular size and glomerular injury score were also elevated in MetS and decreased after ELAM treatment. Evidence of podocyte injury, impaired podocyte mitochondria, and foot process width were all increased in MetS but restored with ELAM. The urinary concentration of pEVs was elevated in MetS pigs and directly correlated with renal dysfunction, glomerular injury, and fibrosis and inversely correlated with glomerular nephrin expression. Additionally, pEV numbers were elevated in the urine of obese compared with lean human patients. Early MetS induces podocyte injury and mitochondrial damage, which can be blunted by mitoprotection. Urinary pEVs reflecting podocyte injury might represent early markers of MetS-related kidney disease and a novel therapeutic target.