Phosphorus Losses Research Articles

Phosphorus fractions and speciation in an alkaline, manured soil amended with alum, gypsum, and Epsom salt.

Snowmelt runoff is a dominant pathway of phosphorus (P) losses from agricultural lands in cold climatic regions. Soil amendments effectively reduce P losses from soils by converting P to less soluble forms; however, changes in P speciation in cold climatic regions with fall-applied amendments have not been investigated. This study evaluated P composition in soils from a manured field with fall-amended alum (Al2(SO4)3·18H2O), gypsum (CaSO4·2H2O), or Epsom salt (MgSO4·7H2O) using three complementary methods: sequential P fractionation, scanning electron microscopy with energy-dispersive X-rays (SEM-EDX) spectroscopy, and P K-edge X-ray absorption near-edge structure spectroscopy (XANES). Plots were established in an annual crop field in southern Manitoba, Canada, with unamended and amended (2.5 Mg ha-1) treatments having four replicates in 2020 fall. Soil samples (0-10cm) taken from each plot soon after spring snowmelt in 2021 were subjected to P fractionation. A composite soil sample for each treatment was analyzed using SEM-EDX and XANES. Alum- and Epsom salt-treated soils had significantly greater residual P fraction with a higher proportion of apatite-like P and a correspondingly lower proportion of P sorbed to calcite (CaCO3) than unamended and gypsum-amended soils. Backscattered electron imaging of SEM-EDX revealed that alum- and Epsom salt-amended treatments had P-enriched microsites frequently associated with aluminum (Al), iron (Fe), magnesium (Mg), and calcium (Ca), which was not observed in other treatments. Induced precipitation of apatite-like species may have been responsible for reduced P loss to snowmelt previously reported with fall application of amendments.

Spring applied phosphorus loss with cover crops in no-till terraced field

Cover crops (CC) can improve phosphorus (P) cycling by reducing water related P losses and contributing to P nutrition of a rotational crop. This is particularly important in claypan soils with freeze-thaw cycles in early spring in the Midwest U.S. This 4-year study (2019–2022) examined the impact of CC monoculture and mix of CC species on P losses from a fertilizer application, and determined the P balance in soil compared to no cover crop (noCC). The CC mix consisted of wheat (Triticum aestivum L.), radish (Raphanus raphanistrum subsp. Sativus), and turnip (Brassica rapa subsp. Rapa) (3xCCmix) in 2019 and 2021 before corn, and cereal rye (Secale cereale L.) was planted as monoculture before soybean in 2020 and 2022. The 3xCCmix had no effect on total phosphorus (TP) and dissolved reactive phosphorus (PO4–P) concentration or load in 2019 and 2021. Cereal rye reduced TP and PO4–P load 70% and 73%, respectively, compared to noCC. The variation in soil moisture, temperature, and net precipitation from fertilizer application until CC termination affected available soil P pools due to variability in CC species P uptake, residue decomposition, and P loss in surface water runoff. Overall, the P budget calculations showed cereal rye had 2.4 kg ha−1 greater P uptake compared to the 3xCCmix species which also reduced P loss in water and had greater differences in soil P status compared to noCC. This study highlights the benefit of CCs in reducing P loss in surface runoff and immobilizing P through plant uptake. However, these effects were minimal with 3xCCmix species and variability in crop residue decomposition from different CC species could affect overall P-soil balance.

Effects of different protein sources in low-phosphorus diets on calculated basal endogenous loss of phosphorus by growing pigs

The objective of this experiment was to test the hypothesis that the basal endogenous loss (BEL) of P from pigs fed a diet containing spray dried plasma, casein, or potato protein concentrate is not different from that of pigs fed a diet containing gelatin. Forty pigs (body weight: 19.34 kg; SD = 0.80) were housed individually in metabolism crates and allotted to four low-P diets using a completely randomized block design with two blocks of 20 pigs and five pigs per diet in each block. Diets were based on cornstarch and sucrose and contained 200 g/kg gelatin, 200 g/kg spray dried plasma, 185 g/kg casein, or 200 g/kg potato protein concentrate. With the exception of Ca and P, diets were formulated to meet requirements of all nutrients. Feces and urine samples were collected for 4 d following a 5-d adaptation period. Fecal samples were dried and ground, and fecal and urine samples were analyzed for P. Data were analyzed using a model that included diet as fixed effect and block as random effect. Results indicated that feed intake and fecal excretion of dry matter were greater (P < 0.05) in pigs fed diets containing spray dried plasma, casein, or potato protein concentrate compared with pigs fed the gelatin diet, with pigs fed potato protein concentrate having the greatest (P < 0.05) excretion. The apparent total tract digestibility (ATTD) of dry matter was least (P < 0.001) in pigs fed the diet containing potato protein concentrate, but there were no differences among gelatin, spray dried plasma, and casein diets. The ATTD of P was greater (P < 0.001) in pigs fed diets containing spray dried plasma or casein compared with pigs fed gelatin or potato protein concentrate diets. The BEL of P was not different between the gelatin and casein diets (i.e., 176 and 234 mg/kg dry matter intake), but pigs fed diets containing spray dried plasma or potato protein concentrate had greater (P < 0.001) BEL of P (i.e., 338 and 374 mg/kg dry matter intake) compared with pigs fed gelatin or casein diets. In conclusion, the BEL of P was greater if calculated from diets containing spray dried plasma or potato protein concentrate compared with gelatin. However, casein may be an alternative to gelatin to estimate the BEL of P because casein provides a greater amount of P compared with gelatin, which compensates for the deficient level of P in gelatin, but does not affect the BEL of P.

Divergent responses of phosphorus solubilizing bacteria with P-laden biochar for enhancing nutrient recovery, growth, and yield of canola (Brassica napus L.)

The growing global population has led to a heightened need for food production, and this rise in agricultural activity is closely tied to the application of phosphorus-based fertilizers, which contributes to the depletion of rock phosphate (RP) reserves. Considering the limited P reserves, different approaches were conducted previously for P removal from waste streams, while the adsorption of ions is a novel strategy with more applicability. In this study, a comprehensive method was employed to recover phosphorus from wastewater by utilizing biochar engineered with minerals such as calcium, magnesium, and iron. Elemental analysis of the wastewater following a batch experiment indicated the efficiency of the engineered biochar as an adsorbent. Subsequently, the phosphorus-enriched biochar, hereinafter (PL-BCsb), obtained from the wastewater, underwent further analysis through FTIR, XRD, and nutritional assessments. The results revealed that the PL-BCsb contained four times higher (1.82%) P contents which further reused as a fertilizer supplementation for Brassica napus L growth. PL-BCsb showed citric acid (34.03%), Olsen solution (10.99%), and water soluble (1.74%) P desorption. Additionally, phosphorous solubilizing bacteria (PSB) were incorporated with PL-BCsb along two P fertilizer levels P45 (45 kg ha−1) and P90 (90 kg ha−1) for evaluation of phosphorus reuse efficiency. Integrated application of PL-BCsb with half of the suggested amount of P45 (45 kg ha−1) and PSB increased growth, production, physiological, biochemical, and nutritional qualities of canola by almost two folds when compared to control. Similarly, it also improved soil microbial biomass carbon up to four times, alkaline and acid phosphatases activities both by one and half times respectively as compared to control P (0). Furthermore, this investigation demonstrated that waste-to-fertilizer technology enhanced the phosphorus fertilizer use efficiency by 55–60% while reducing phosphorus losses into water streams by 90%. These results have significant implications for reducing eutrophication, making it a promising approach for mitigating environmental pollution and addressing climate change.

New phosphorus losses via tile drainage depend on fertilizer form, placement, and timing.

Agricultural phosphorus (P) losses are harmful to water quality, but knowledge gaps about the importance of fertilizer management practices on new (recently applied) sources of P may limit P loss mitigation efforts. Weighted regression models applied to subsurface tile drainage water quality data enabled estimating the new P losses associated with 155 P applications in Ohio and Indiana, USA. Daily discharge and dissolved reactive P (DRP) and total P (TP) loads were used to detect increases in P loss following each application which was considered new P. The magnitude of new P losses was small relative to fertilizer application rates, averaging 79.3g DRP ha-1 and 96.1g TP ha-1 , or<3% of P applied. The eight largest new P losses surpassed 330g DRP ha-1 or 575g TP ha-1 . New P loss mitigation strategies should focus on broadcast liquid manure applications; on average, manure applications caused greater new P losses than inorganic fertilizers, and surface broadcast applications were associated with greater new P losses than injected or incorporated applications. Late fall applications risked having large new P losses applications. On an annual basis, new P contributed an average of 14% of DRP and 5% of TP losses from tile drains, which is much less than previous studies that included surface runoff, suggesting that tile drainage is relatively buffered with regard to new P losses. Therefore old (preexisting soil P) P sources dominated tile drain P losses, and P loss reduction efforts will need to address this source.

Rainfall impacts on nonpoint nitrogen and phosphorus dynamics in an agricultural river in subtropical montane reservoir region of southeast China

The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers. However, little information is available on how the rainfall affect nutrient dynamics in subtropical montane rivers with complex land use. This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu, a montane reservoir of southeast China. The results showed that riverine total nitrogen (TN) and total phosphorus (TP) concentrations increased continuously with increasing rainfall intensity, while TN:TP decreased. The heavy rainfall and rainstorm drove more than 30% of the annual N and P loading in only 5.20% of the total rainfall period, indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs. NO3−-N is the primary nitrogen form lost, while particulate phosphorus (PP) dominated phosphorus loss. The main source of N is cropland, and the main source of P is residential area. Spatially, forested watersheds have better drainage quality, while it is still a potential source of nonpoint pollution during rainfall events. TN and TP concentrations were significantly higher at sites dominated by cropland and residential area, indicating their substantial contributions to deteriorating river water quality. Temporally, TN and TP concentrations reached high values in May-August when rainfall was most intense, while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities. The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads, providing guidance for nutrient load reduction planning for Lake Qiandaohu.

The importance of consensus science to managing phosphorus in the environment: SERA‐17 and the legacy of Andrew Sharpley

AbstractPhosphorus (P) loss from agricultural systems to surface waters, and ultimately, eutrophication, presents a wicked problem requiring transdisciplinary solutions. The mission of SERA‐17 (Southern Extension and Research Advisory Information Exchange Group‐17) has been to address this problem by developing “Innovative Solutions to Minimize Phosphorus Losses from Agriculture.” Over the course of his career, Dr. Andrew Sharpley demonstrated a rare ability to collaboratively achieve consensus around issues related to the science and management of P. The SERA‐17 organization served as the central community of experts and stakeholders where that consensus was built and applied. The consensus‐based approach, demonstrated by Sharpley and at the core of the SERA‐17 organization, was routinely applied to key areas of P science to produce applied outcomes that have been readily adopted: advance foundational science to resolve knowledge gaps and to promote innovation; promote consistency in methods to facilitate comprehensive investigations and conclusions across a diversity of systems; engage diverse stakeholders to prioritize research, and ultimately, ensure that outcomes reflect a plurality of perspectives; and deliver pragmatic solutions that reflect the best information available at a particular time. We review the history of SERA‐17 in delivering new science and management recommendations for P, with an eye to elucidating Sharpley's role and legacy in this process.

Manure derived hydrochar reduced phosphorus loss risk via an alteration of phosphorus fractions and diversified microbial community in rice paddy soil

Phosphorus (P) loss caused by the irrational use of manure organic fertilizer has become a worldwide environmental problem, which has caused a potential threat to water safety and intensified agricultural non-point source pollution. Hydrothermal carbonization is method with a low-energy consumption and high efficiency to deal with environmental problems. Application of pig manure-derived hydrochar (PMH) to soil exhibited potential of sustainable development compared with the pristine pig manure (PM). However, the effects of PMH on the distribution of P among the fractions/forms and the interaction between microorganisms and P forms and its relevance to the potential loss of P in paddy fields has not been clarified. Therefore, in this study, a soil column experiment was conducted using the untreated soil (control), and the PM, PMH1 (PMH derived at 180 °C), and PMH2 (PMH derived at 260 °C) treated soils (at the dose of 0.05 %) and rice was cultivated to investigate the effects of PM and PMH on the P fractions, mobilization, ad potential loss via the induced changes on soil microbial community after a complete growing season of rice. The trend of P utilization was evaluated by P speciation via continuous extraction and 31P NMR. The addition of PMH reduced the proportion of residual P in soil by 23.8–26.3 %, and increased the proportion of HCl-P and orthophosphate by 116.2–158.6 % and 6.1–6.8 % compared to PM. The abundance of gcd gene developed after the application of PMH2, which enhanced the mobile forms of soil P utilization via secreting gluconic acid. The network diagram analysis concluded that the changes in various P forms were mainly related to Proteobacteria, Bacteroides, Firmicutes and Acidobacteria. The results illustrated that PMH mitigate the potential risk of P loss more than PM by altering P fractions and affecting soil microbial community.

Soil texture as a regulatory pathway for the enrichment of aggregate‐associated phosphorus

AbstractSoil phosphorus (P) loss induced by erosion is an imminent threat to global food security, and as the linkage between erosion and P loss, aggregate is the unit for soil P storage. This study investigated the impacts of soil texture on aggregate‐associated P and its enrichment rate by using soils with four typical textures (silty clay, clay loam, silty clay loam, and loam) from croplands with the same field management in Danjiangkou (Hubei, China), the water source for the Middle Route of South‐to‐North Water Diversion. The initial P concentration in the range of 36.5 to 411.2 mg kg−1 was generated by laboratory incubation, and aggregate‐associated P was determined by the combination of wet sieving and molybdenum blue colorimetric method. Aggregate‐associated P was shown to be mainly concentrated in &lt;0.05 mm aggregates (23.20–315.52 mg kg−1), accounting for 30.71%–35.28% of P concentration for a unit mass of soil. In addition, aggregate‐associated P and its enrichment rate generally decreased with the decline of clay content (333.76–63.25 mg kg−1 in 1–0.5 mm size aggregate) under the same aggregate size fraction, while they all exhibited a unimodal distribution (increasing first and then decreasing) with decreasing aggregate size. Moreover, clay content made the most contribution to the increase of aggregate‐associated P (R2 &gt; 0.56) and its enrichment rate (R2 = 64.4%, p &lt; 0.01), while CaCO3 showed a contrary trend (R2 &gt; 0.56, and R2 = 49.1%, p &lt; 0.01). Collectively, variations of aggregate‐associated P and ERi were mainly attributed to soil clay fraction‐regulated P adsorption.

Effects of type of fiber sources in the phosphorus-free diet on the endogenous losses of phosphorus in growing pigs

An experiment was conducted to investigate the influence of fiber sources in phosphorus (P)-free diets on the endogenous losses of P in growing pigs. Eight barrows with an initial body weight of 37.4 kg (standard deviation = 2.7) were individually housed in metabolism crates. The animals were allotted to dietary treatments in a replicated 4 × 4 Latin square design with 4 diets, 8 animals, and 4 periods. Four P-free diets were based mainly on cornstarch, sucrose, and gelatin, and contained 10% purified cellulose, pectin, silica sand, or sawdust as a fiber source in each P-free diet. Each period consisted of a 4-d adaptation period and a 4-d collection period. Feces were collected quantitatively according to the marker-to-marker procedure. The feed intake of pigs fed the sawdust diet was less (P < 0.05) than that of pigs fed the silica sand diet. The total fecal output of pigs fed the purified cellulose or silica sand diet was greater (P < 0.05) than that of pigs fed the pectin diet. Fecal P concentrations were less (P < 0.05) in the pigs fed the purified cellulose or silica sand diet compared with the pigs fed the pectin diet. Total P output was not affected by fiber sources. The endogenous loss of P was 206, 350, 252, and 431 mg/kg dry matter intake (standard error of the means = 45.2) in the purified cellulose, pectin, silica sand, and sawdust diets, respectively. There were differences (P < 0.05) in the coefficient of apparent total tract digestibility of dry matter, organic matter, crude protein, ether extract, and calcium among experimental diets. In conclusion, fiber sources may have different effects on the endogenous P losses and the apparent total tract digestibility of nutrients.

Characteristics of nitrogen and phosphorus contents in soil and water in an agricultural catchment of the three Gorges reservoir area

To explore the impact of different land use modes on the contents of nitrogen and phosphorus in soil and water in the agricultural basin of the Three Gorges Reservoir, the differences in the nitrogen and phosphorus contents in soil and shallow groundwater under different land use modes were studied by using sample data collected in the field. The typical agricultural small watershed at the heart of the reservoir area was selected as the research object. The differences in the nitrogen and phosphorus loss concentrations during the rainfall process and in the daily surface runoff of the two subcatchments with different land use compositions and spatial layouts were compared. The results show that under the five land use modes, the average total nitrogen (TN) content of the paddy soil (1.51 g/kg) was the highest and was significantly higher than that of the other four land use modes (p &amp;lt; 0.05); the average nitrate nitrogen (NO3−-N) content of the terraced soil in dry land (30.05 mg/kg) was the highest, and the dispersion degree was the greatest; and the total phosphorus (TP) content of the three types of sloping farmland was higher than that of terraced farmland, among which the total phosphorus content of the dryland sloping farmland (1.37 g/kg) was the highest and was significantly greater than that of the other types (p &amp;lt; 0.05); moreover, the available phosphorus (AP) content in the soil of the closely planted mulberry garden was the highest, with an average of 36.85 mg/kg. Under the different land use modes, the concentrations of TN and NO3−-N in the shallow groundwater varied greatly, while there were no obvious differences in the TP concentrations. Influenced by fertilization, the concentrations of TN and NO3−-N in the shallow groundwater clearly increased after fertilization in spring and autumn. The concentration of TP increased slightly, and the concentration was the highest when the rainfall was concentrated in summer. A comparison of the two subcatchments revealed that the interplanted mulberry and paddy fields at the bottom of the basin effectively reduced TN and TP outputs of surface runoff in the subcatchment.

Assessment of phosphorus flow of canteen food waste in educational institutions in Bangkok area

This study was to investigate the occurrence of food waste in educational institutions and their current food waste management. Three educational institutions in Bangkok area were selected, and sampling were conducted for three days in a row for each institution. The results showed that the amount of food waste ranging from 20 to 198 kg/day, accounting of 40 – 90% of total waste. Most of food waste was eventually ended up in landfills. The phosphorus proportion of uncooked food waste (UCFW) was in the range of 0.09 – 0.29 mg P/g, while that of cooked food waste (CFW) was in the range of 0.53 – 0.76 mg P/g. Total phosphorus mass entering the waste management system was ranging from 8 to 141 g P/d, while loss of phosphorus was in the range of 1.5 – 13.5 g P/d. Under the composting scenario used in this study, the yield of fertilizer-like product ranged from 0.3 to 37.2 tons per year resulting in calculated cost saving as high as 391 USD per year. From this study, food waste separation was highly recommended to improve assessment of phosphorus flow and recovery. Expectation of phosphorus recovery for agricultural sector benefits should be prioritized.

Effects of climate change and land use change on runoff, sediment, nitrogen and phosphorus losses in the Haihe River Basin

Effects of climate change and land use change on runoff, sediment, nitrogen and phosphorus losses in the Haihe River Basin

Ciclagem de Nitrogênio, Fósforo e Potássio em Ecossistemas de Pastagem

Abstract Inadequate management practices are the main factors that can cause pasture degradation, and one of the key factors is to understand the nutrient cycling in pasture ecosystems. This review aimed to describe the cycling processes of important nutrients in pasture ecosystems (nitrogen, phosphorus, and potassium), analyzing the interactions of soil-plant-animal components. The use of forage legume species intercropped with grasses is a strategy to increase the nitrogen content in the soil, minimizing costs with nitrogen fertilization in pastures. Manure and plant residues are great organic sources of phosphorus and potassium but are also fundamental for supplying microminerals. Nitrogen losses in pastures are mainly caused by leaching, runoff, and volatilization. The addition of phosphorus to the soil must be performed carefully, as there is an increase in phosphorus losses with increasing accumulation in the soil. Phosphorus is often returned to the soil far from where it was used, so the stock transfer represents a loss in pasture ecosystems that can account for approximately 5% of the inputs of phosphate fertilizers. Potassium losses mostly occur by leaching and runoff. Improving management practices is essential for balanced nutrient cycling in pasture ecosystems.

Effect of Soil Amendment of Greening Waste on Leaching Loss of Soil Nitrogen and Phosphorus

It is of great practical significance for comprehensively promoting the green development of agriculture to explore practical products for preventing and controlling nitrogen and phosphorus leaching. In this study, PVC soil column experiments and field experiments were used to evaluate the interception effect of soil amendments produced by green wastes on nitrogen and phosphorus leaching. The pH value, EC value, the nutrient contents of ammonium nitrogen (NH4 +-N), nitrate nitrogen (NO3 −-N), total nitrogen (TN), and available phosphorus (AP) in different soil layers and leaching solution were determined, and the interception effects of soil amendment on nitrogen and phosphorus leaching were comprehensively evaluated. The results showed that the soil amendments of green waste had significant inhibition and control effects on the leaching of NH4 +-N, NO3 −-N, APs, and TN. The interception mechanism of the soil amendments of green waste on nitrogen and phosphorus leaching was mainly to absorb a large amount of leaching solution and various forms of nitrogen and phosphorus nutrients. The results also showed that the soil amendment of green waste had a certain nutrient content and buffering effect on acid and alkali and the main form of nitrogen leaching was NO3 −-N. This study provides a theoretical basis for the development of cheap and effective physical products to prevent and control nitrogen and phosphorus leaching from farmland.

Loss of nitrogen, phosphorus, and potassium through surface runoff under simulated rainfall in different soil management systems

Loss of nitrogen, phosphorus, and potassium through surface runoff under simulated rainfall in different soil management systems

Effect of Fertilizer, Furrow Length, and Irrigation Flow Rate on Soil Nutrient and Yield of Apple Orchard

The objective of this study was to evaluate the impact of furrow irrigation with a length of 96, 144, and 192 m and a flow rate of between 0.2 and 0.4 Ls−1 on the leaching of nitrogen, phosphorus, and humus from dry subtropical soils in Azerbaijan. Moreover, the impact of six fertilizer levels, namely, control (without fertilizer), 10 t ha−1 of cow manure, N90P90K90 + 10 t ha−1 of cow manure, N120P90K90 + 10 t ha−1 of cow manure, N120P120K90 + 10 t ha−1 of cow manure, and N120P90K120 + 10 t ha−1 of cow manure, on the performance of apple orchards, has been examined. The findings indicate that the brown soils of the irrigated grassland exhibit normal humus, total nitrogen, and weak phosphorus levels, with a gradual decline observed in the lower layers. Applicable to the agricultural and subsurface layers, the aggregates are 0.25–1.0 mm in diameter, with an agricultural value of 12.9% and 21.8%, respectively. This indicates a poor structural condition of the apple orchard soil. The elevation of the water flow rate from 0.2 to 0.4 Ls−1 resulted in a greater extraction of humus, nitrogen, and phosphorus from the soil. Both water flow rates increased the nutrients and humus leaching from the soil. By extending the furrow length to 192 m, the losses of humus (3.25%), nitrogen (0.36%), and phosphorus (0.30%) from the soil in both water flows significantly increased in comparison to the 96‐m length. By extending the length of furrows to 192 m, the yield (21.97 t ha−1) was significantly reduced in comparison to the 96‐m length (22.31 t ha−1). As a consequence of the application of N120P90K120 + 10 t ha−1 of cow manure, the yield of 27.3 t ha−1 was significantly elevated in comparison to other fertilizer treatments and the control treatment (17.9 t ha−1). Therefore, management of fertilizer systems, furrow length, and water flow can improve soil fertility and plant yield by reducing erosion in the meadow‐brown soil of Azerbaijan.

Phosphorus recycling and loss from compost‐amended urban gardens: Results from a 7‐year study

AbstractUrban vegetable gardens provide an opportunity to recycle nutrients from food waste back into the human food system through the application of compost. However, a reliance on compost for soil fertility can lead to excess phosphorus (P) inputs that can build up in garden soil and potentially be exported via leachate or runoff. We report the results of a 7‐year experiment in a campus research garden in which replicated raised‐bed garden plots received manure‐based compost or municipal compost that was applied at a higher rate targeted to meet crop nitrogen demand or a lower rate targeted to meet crop P demand. Control plots received either no soil inputs or targeted synthetic fertilizer. Higher input treatments for both types of composts showed steadily increasing concentrations of soil plant‐available P, with a corresponding increase in leachate phosphate concentration. For both higher input compost treatments, approximately 30% of P added as compost was recovered in harvested crops over the 7‐year period, compared to &gt;88% in the lower input compost treatments. In both high‐ and low‐input manure compost treatments, export of P as leachate accounted for approximately 10% of total P input, compared to 4% for the municipal compost. Over the 7‐year study period, P exported as leachate ranged from 0.8 g P/m2 in the no‐input treatments to 6.5 g P/m2 in the higher input manure compost treatments. These results show that tradeoffs are not inevitable as targeted compost applications can lead to high yield and low leachate export.

Pervasive soil phosphorus losses in terrestrial ecosystems in China

AbstractFuture phosphorus (P) shortages could seriously affect terrestrial productivity and food security. We investigated the changes in topsoil available P (AP) and total P (TP) in China's forests, grasslands, paddy fields, and upland croplands during the 1980s–2010s based on substantial repeated soil P measurements (63,220 samples in the 1980s, 2000s, and 2010s) and machine learning techniques. Between the 1980s and 2010s, total soil AP stock increased with a small but significant rate of 0.13 kg P ha−1 year−1, but total soil TP stock declined substantially (4.5 kg P ha−1 year−1) in the four ecosystems. We quantified the P budgets of soil–plant systems by harmonizing P fluxes from various sources for this period. Matching trends of soil contents over the decades with P budgets and fluxes, we found that the P‐surplus in cultivated soils (especially in upland croplands) might be overestimated due to the great soil TP pool compared to fertilization and the substantial soil P losses through plant uptake and water erosion that offset the P additions. Our findings of P‐deficit in China raise the alarm on the sustainability of future biomass production (especially in forests), highlight the urgency of P recycling in croplands, and emphasize the critical role of country‐level basic data in guiding sound policies to tackle the global P crises.

Contributions From a Southern Minnesota Saturated Buffer Field Site: Agricultural Best Management Practices and Dissolved Phosphorus Loss

Contributions From a Southern Minnesota Saturated Buffer Field Site: <i>Agricultural Best Management Practices and Dissolved Phosphorus Loss</i>