Effects of the nitrification inhibitor nitrapyrin on urea-based fertilizers in a Mediterranean calcareous soil: N dynamics and microbial functional genes.

2020 ◽  
Author(s):  
Georgios Giannopoulos ◽  
Lars Elsgaard ◽  
Georgios Zanakis ◽  
Rima B. Franklin ◽  
Bonnie L. Brown ◽  
...  
Keyword(s):  
Calcareous Soil ◽  
Crop Yields ◽  
Nitrification Inhibitor ◽  
Urea Hydrolysis ◽  
Nitrification Inhibitors ◽  
Agricultural Practice ◽  
Soil N ◽  
N Transformations ◽  
Total N ◽  
Significant Difference

<p>Nitrogen (N) fertilization is an essential agronomic practice, which increases crop yields and improves soil fertility. Globally, more than 110 x 10<sup>9</sup> kg of chemical N fertilizers are applied each year with urea-N being one of the most affordable options. Upon urea hydrolysis, any portion not assimilated by crops is either volatilized as NH<sub>3</sub> or microbially nitrified (i.e., NH<sub>4</sub><sup>+</sup> oxidized) to leachable NO<sub>3</sub><sup>-</sup> and NO<sub>2</sub><sup>-</sup>. Nitrification inhibitors (NI) are increasingly co-applied as a sustainable agricultural practice and block the process of nitrification, resulting in a temporal increase of NH<sub>4</sub><sup>+</sup> in the soils. Several studies have documented the effectiveness of NIs in retaining soil NH<sub>4</sub><sup>+</sup> and increasing crop yields, but less is known about the effects of NIs on the fate of urea–N and the overall impact of NIs on the soil microbial community.</p><p>In a 60 day soil mesocosm experiment, we investigated the effects of Nitrapyrin (NI; 2-chloro-6-(trichloromethyl)pyridine) co-applied with a selection of urea-based fertilizers: urea (U); U with urease inhibitors (U+UI); methylene-urea (MU); and zeolite-coated urea (ZU), on a typical Mediterranean soil under ambient summer conditions. We showed that NI applied with urea fertilizers resulted in a slower decay of extractable NH<sub>4</sub><sup>+</sup> with a concurrent increase in NH<sub>3</sub> volatilization. Integrated measures of soil NH<sub>4</sub><sup>+</sup> were 1.5 to 3.3-fold greater when NI was applied. At the same time, there was a 10 to 60% reduction in integrated measures of NO<sub>3</sub><sup>-</sup> and NO<sub>2</sub><sup>-</sup> when NI was applied with the tested fertilizer types, except MU fertilizer where the integrated measures of NO<sub>3</sub><sup>-</sup> and NO<sub>2</sub><sup>-</sup> doubled. Upon urea hydrolysis, the released NH<sub>4</sub><sup>+</sup> was transformed to NO<sub>3</sub><sup>-</sup> and NO<sub>2</sub><sup>-</sup>, which subsequently decreased in concentration following a typical nitrification - denitrification pathway in the absence of plants. Soil N<sub>2</sub>O emissions from urea fertilizers were reduced by 40% with UI, 50% with NI, and 66% with NI + UI.</p><p>Interestingly, 15 days after the application of NI, there was a decrease in bacterial abundance (eub genes; qPCR) in all fertilized treatments. NI dramatically reduced the abundance of ammonia-oxidizing microbes (amoA genes) and there were fewer bacteria associated with denitrification genes (nirK, nirS, nosZ) when NI was applied. </p><p>At the end of the experiment, there was no significant difference in total N among all fertilized soils. Total N was in excess when compared to the control, and it was a considerable N pool potentially immobilized in microbial biomass in the absence of crops.</p><p>In conclusion, the use of NI doubled NH<sub>4</sub><sup>+</sup> retention in the soil and decreased soil N<sub>2</sub>O emission by 50%, through negatively affecting ammonia oxidizing and denitrifying microbes and subsequently reducing soil available NO<sub>3</sub><sup>-</sup> and NO<sub>2</sub><sup>-</sup>. The application of NIs should be carefully planned and synchronized (timing) with crop growth to reduce subsequent N transformations and N loss to the environment.</p><p><strong>Keywords</strong><strong>:</strong> urea, zeolite, methylene-urea, nitrification inhibitor, nitrapyrin, calcareous soil, soil nitrogen</p>

scholarly journals Innovative Controlled-Release Polyurethane-Coated Urea Could Reduce N Leaching in Tomato Crop in Comparison to Conventional and Stabilized Fertilizers

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1827
Author(s):  
Luca Incrocci ◽  
Rita Maggini ◽  
Tommaso Cei ◽  
Giulia Carmassi ◽  
Luca Botrini ◽  
...  
Keyword(s):  
Controlled Release ◽  
Crop Yields ◽  
Nutrient Use Efficiency ◽  
Nitrification Inhibitor ◽  
Fruit Production ◽  
N Leaching ◽  
Vegetable Production ◽  
Tomato Crop ◽  
Total N ◽  
Coated Urea

Large amounts of fertilizers are being used in agriculture to sustain growing demands for food, especially in vegetable production systems. Soluble fertilizers can generally ensure high crop yields, but excessive leaching of nutrients, mainly as nitrate, can be a major cause of water pollution. Controlled-release fertilizers improve the nutrient use efficiency and lower the environmental hazard, usually without affecting the production. In this study, an innovative controlled-release coated urea fertilizer was compared to conventional nitrogen (N) fertilizers and a soluble ammonium-based fertilizer containing a nitrification inhibitor, in a round table tomato cultivation. Both the water and N balance were evaluated for each treatment, along with the yield and quality of the production. The experiment was repeated in three different seasons (spring, autumn and summer-autumn) in a glasshouse to prevent the effect of uncontrolled rainfall. The results indicated that N leaching decreased by increasing the percentage of coated urea. The application of at least 50% total N as coated urea strongly reduced N leaching and improved N agronomic efficiency in comparison with traditional fertilizers, ensuring at the same time a similar fruit production. Due to reduced leaching, the total N amount commonly applied by growers could be lowered by 25% without detrimental effects on commercial production.

The nitrification inhibitor dicyandiamide increases mineralization–immobilization turnover in slurry-amended grassland soil

2014 ◽  
Vol 152 (S1) ◽  
pp. 137-149 ◽  
Author(s):  
M. ERNFORS ◽  
F. P. BRENNAN ◽  
K. G. RICHARDS ◽  
K. L. MCGEOUGH ◽  
B. S. GRIFFITHS ◽  
...  
Keyword(s):  
Nitrification Inhibitor ◽  
Organic N ◽  
Nitrification Inhibitors ◽  
N Losses ◽  
N Transformations ◽  
Autotrophic Nitrification ◽  
Gross Mineralization ◽  
Soil N Mineralization ◽  
Inhibition Of Nitrification ◽  
Gross N Transformation

SUMMARYNitrification inhibitors are used in agriculture for the purpose of decreasing nitrogen (N) losses, by limiting the microbially mediated oxidation of ammonium (NH4+) to nitrate (NO3−). Successful inhibition of nitrification has been shown in numerous studies, but the extent to which inhibitors affect other N transformations in soil is largely unknown. In the present study, cattle slurry was applied to microcosms of three different grassland soils, with or without the nitrification inhibitor dicyandiamide (DCD). A solution containing NH4+and NO3−, labelled with15N either on the NH4+or the NO3−part, was mixed with the slurry before application. Gross N transformation rates were estimated using a15N tracing model. In all three soils, DCD significantly inhibited gross autotrophic nitrification, by 79–90%. Gross mineralization of recalcitrant organic N increased significantly with DCD addition in two soils, whereas gross heterotrophic nitrification from the same pool decreased with DCD addition in two soils. Fungal to bacterial ratios were not significantly affected by DCD addition. Total gross mineralization and immobilization increased significantly across the three soils when DCD was used, which suggests that DCD can cause non-target effects on soil N mineralization–immobilization turnover.

Influence of different nitrogen inhibitors on maize yield

2021 ◽  
Author(s):  
Maria Heiling ◽  
Mahdi Shorafa ◽  
Rayehe Mirkhani ◽  
Elden Willems ◽  
Arsenio Toloza ◽  
...  
Keyword(s):  
Block Design ◽  
Nitrification Inhibitor ◽  
Maize Yield ◽  
N Fertilizer ◽  
Control Treatment ◽  
Nitrification Inhibitors ◽  
Stable Form ◽  
N Losses ◽  
N Fertilizers ◽  
Significant Difference

<p>Nitrogen (N) fertilizer management is challenging due to the many factors and have low N use efficiency (NUE). Heavy N losses from soil reduce plant yield and have negative impacts on the environment. Nitrogen processes inhibitors, such as urease and nitrification inhibitors (UI and NI), are chemical compounds which reduce urea hydrolysis and nitrification respectively. By coating ammonium based chemical fertilizers with N process inhibitors allows N to stay in a more stable form of ammonium (NH<sub>4</sub><sup>+</sup>) thus minimising N losses as well as improving NUE and consequently enhancing crop yield.</p><p>A field experiment was established at the Soil and Water Management and Crop Nutrition Laboratory (SWMCNL) in Seibersdorf, Austria to determine the effect of different N fertilizers coated with N process inhibitors on maize yield in summer 2020. The field site is characterised by a moderately shallow Chernozem soil with significant gravel content. Three combinations of N fertilizer (urea or NPK) with N process inhibitors (UI and/or NI)) were tested and compared with a control treatment (without N fertilizer) and a urea application without any inhibitor. All treatments received 60 kg ha<sup>-1</sup> P<sub>2</sub>O<sub>5</sub> and 146 kg ha<sup>-1</sup> K<sub>2</sub>O. The amount of N added to each treatment receiving N fertilizer was 120 kg N ha<sup>-1</sup>. The inhibitors used were (i) UI (2-NPT: N-(2-nitrophenyl) phosphoric acid triamide), (ii) NI-1 (MPA: N-[3(5)-methyl-1H-pyrazol-1-yl) methyl] acetamide), and (iii) NI-2 (DMPP: 3,4-dimethylpyrazole phosphate). DMPP, a nitrification inhibitor, was used in combination with NPK fertilizer. A randomized complete block design with four replications was used in this study. Treatments were: T<sub>1</sub> (control treatment - without N fertilizer), T<sub>2</sub> (Urea only), T<sub>3</sub> (Urea + UI), T<sub>4</sub> (Urea + UI + NI-1), and T<sub>5 </sub>(NPK + NI-2). Urea was applied through two split applications in the T<sub>2</sub> treatment. In T<sub>3</sub>, T<sub>4</sub>, and T<sub>5</sub> treatments, N fertilizers were applied only once. Supplemental irrigation was only applied in the early stages of growth, to ensure that the crop could establish. Harvest was carried out at 98 days after planting.</p><p>The yield data showed that different fertilizer treatments had a significant (p ≤ 0.01) effect on maize yield (dry matter production). There was no significant difference between treatments 4 and 5, which had the highest yield followed by treatments 2 and 3. The comparison between T<sub>2</sub> and T<sub>3</sub> showed that the application of a urease inhibitor avoids the need for a split application of urea, which decreases labour costs. Adding NI-1 (under T<sub>4</sub>) further increases the yield. Also, the package of NPK, a common choice by farmers in Austria, in combination with the nitrification inhibitor NI-2 showed equally good results as urea combined with two inhibitors. Based on the yield results, it can be concluded that N process inhibitors play a significant role in enhancing maize yields.</p>

scholarly journals Using the Nitrification Inhibitor Nitrapyrin in Dairy Farm Effluents Does Not Improve Yield-Scaled Nitrous Oxide and Ammonia Emissions but Reduces Methane Flux

2021 ◽  
Vol 5 ◽  
Author(s):  
Ana Gabriela Pérez-Castillo ◽  
Jimmy Arrieta-Méndez ◽  
Jorge Alberto Elizondo-Salazar ◽  
Mayela Monge-Muñoz ◽  
Mohammad Zaman ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Block Design ◽  
Nitrification Inhibitor ◽  
Dairy Farm ◽  
Previous Treatment ◽  
Costa Rican ◽  
Experimental Conditions ◽  
N Losses ◽  
Total N ◽  
Significant Difference

The application of dairy farm effluents (DFE) without previous treatment in paddocks was intensified due to the approval of this practice in Costa Rican legislation since 2012. Applying DFE instead of synthetic N fertilizer in grasslands is an opportunity to reach a circular economy; however, this practice increases the risk of emissions of nitrous oxide (N2O), methane (CH4), and ammonia (NH3), which contribute to global warming. A field experiment was carried out using a permanent grassland (90% Star grass and 10% Kikuyo grass) to simultaneously assess the effect of nitrapyrin on yield-scaled emissions of NH3, CH4, and N2O. The experiment lasted for 5 months in 2017, based on a randomized complete block design, including three treatments of control (CK) without N application, surface application of DFE with nitrapyrin (SNI), and without nitrapyrin (S). Total N applied was 149 ± 12 kg N ha−1 for both S and SNI treatments split into five applications. CH4 emissions from S, SNI, and CK showed a high temporal variation. Daily fluxes of CH4 from SNI were significantly lower than those of S in August (P < 0.05). Cumulative emissions of CH4, the majority produced in the soil, ranged from 4 to 168 g ha−1 for S, and from −13 to 88 g ha−1 for SNI. The ratio between the N2O cumulative emissions and the N applied as DFE were 1.6 ± 0.5 and 1.7 ± 0.2% for S and SNI, respectively. NH3 volatilization potential was very low (i.e., 0.6 ± 0.2% of the N applied). Under the prevailing experimental conditions, no significant difference between yield-scaled NH3 and N2O emissions were found between S and SNI, suggesting that nitrapyrin may not be a viable mitigation option for gaseous N losses from DFE application in Costa Rican grasslands in rainy season.

scholarly journals Synergistic Effect of Urease and Nitrification Inhibitors in the Reduction of Ammonia Volatilization

2021 ◽  
Author(s):  
Asim Hussain, ◽  
Zara Jabeen ◽  
Nadia Afsheen ◽  
Hamza Rafiq ◽  
Zill e Huma ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Crop Yields ◽  
Ph Value ◽  
Good Practice ◽  
Urea Hydrolysis ◽  
Nitrification Inhibitors ◽  
Maximum Height ◽  
The Novel ◽  
N Loss ◽  
Use Efficiency

<p>Nitrogen (N) is deficient in more than 90% of soils of Pakistan mainly because of low organic matter contents. The use of nitrogenous fertilizers is a common practice for sustainable and profitable crop yields. A significant portion of added fertilizers is lost through volatilization, leaching, and denitrification. Low use efficiency of these fertilizers in our climate is a serious concern because of high costs and environmental issues. The present study evaluated the novel synergistic effect of urease and nitrification inhibitors such as ammonium thiosulfate (ATS) and 2-Chloro-6-(trichloromethyl)pyridine (Nitrapyrin) to reduce the urea hydrolysis in the soil of Faisalabad, Gujranwala, and Sheikhupura to manage the ammonia as well as N loss. Three different combinations such as A1, A2, and A3 of both inhibitors were prepared with different ratios of 1:1, 0.25:0.75, 0.75:0.25, respectively. Results showed that the minimum urea hydrolysis of about 2.41, 2.79, and 4.68 IU/g soil with A1 combination after 4<sup>th</sup>-day observation with the rate of 0.50% concentration for Faisalabad, Gujranwala, and Sheikhupura, respectively. In addition, results showed the better urease activity at a pH value of 6.50, incubation time of 30 min, and temperature of 37 ℃ for all A1, A2, and A3 combinations with 0.50% concentration. Moreover, inhibitors treated urea showed the plant maximum height of 111, 101, and 101 cm, and root length of 15, 11, and 5 cm, number of tillers of 14, 16, and 19 per panicle, and number of spikes of 37, 21 and 38 per panicle with A1, A2, and A3 combination at 0.50% dose respectively in Faisalabad soil. Overall, it is concluded that 0.50% inhibitor concentration showed the much impressive urease inhibition results followed by 0.25 and 0.10%. However, the application of inhibitors was a good practice to reduce the N loss from soil.</p>

FARMER’S PERCEPTION OF CLIMATE CHANGE AND ITS ASSOCIATION WITH DEMOGRAPHIC CHARACTERISTICS IN MAIZE PRODUCING AREA OF NORTHERN, NIGERIA

2021 ◽  
Vol 4 (4) ◽  
pp. 200-206
Author(s):  
Buba Adamu Ndawayo ◽  
Abdullahi Adamu
Keyword(s):  
Climate Change ◽  
Crop Yields ◽  
Northern Region ◽  
Agricultural Practice ◽  
Demographic Information ◽  
Chi Square ◽  
Maize Production ◽  
Significant Difference ◽  
Cross Tabulation ◽  
And Gender

This study was designed to found farmers’ perception on climate change and weather changeability using farmers’ demographic information to analyze gender exertion with education level in maize producing areas of the northern region, and its impacts on crop yields. Purposive sampling was used to select a sample size of 400 households. Information was composed from heads of households using a questionnaire and the data obtained were analyzed using statistical analysis. The results showed that farmers perceived climate change and weather variability correctly. The result of the independent-sample t-test on-farmers’ perception about climate change and farming status shows that there was a significant difference in perception of climate change between farmers and non-farmers. chi-square cross-tabulation also demonstrated that there is a significant association between farmers’ level of perception of climate change and gender. Lastly, the study outcome indicates that there was no significant difference in farmers’ perception based on the educational level of the farmers. These findings will be used by both institutions and government in formulating policies and funding for better maize production and agricultural practice in genera

Kinetics and thermodynamics of urea hydrolysis in the presence of urease and nitrification inhibitors

2020 ◽  
pp. 1-11
Author(s):  
Ahmed A. Lasisi ◽  
Olalekan O. Akinremi
Keyword(s):  
Soil Temperature ◽  
Half Life ◽  
Nitrification Inhibitor ◽  
Inhibitory Effect ◽  
Urea Hydrolysis ◽  
Hydrolysis Rate ◽  
Effect Of Temperature ◽  
Nitrification Inhibitors ◽  
Urease Inhibitor ◽  
N Losses

Urease inhibitor [N-(n-butyl) thiophosphoric triamide (NBPT)] and nitrification inhibitor (NI) (3,4-dimethylpyrazole phosphate) have been used to reduce nitrogen (N) losses from urea-based fertilizers. This study evaluated the effect of temperature, NBPT, and NI on kinetic and thermodynamic properties of urea hydrolysis in six soils. Soils were amended (250 kg N·ha−1) with urea (UR), NBPT treated urea (URNBPT), or NBPT + NI treated urea (URDI), incubated at 5, 15, or 25 °C, and destructively sampled eight times during an 18 d incubation. We measured urea hydrolysis rate by the disappearance of urea with time and determined the rate constant (k; d−1) assuming first-order kinetics. Our results showed that k increased with temperature in the order of 0.07 (5 °C), 0.12 (15 °C), and 0.20 (25 °C) across soils and inhibitor treatments. In addition, k declined in the order of UR (0.19) > URDI (0.11) > URNBPT (0.08) across soils and temperatures. Although urease inhibitor, NBPT, increased the half-life of urea from 3.8 to 8.3 d across soil–temperature, the addition of a NI significantly reduced the half-life of NBPT treated urea by approximately 2 d across soil–temperature. Thermodynamics parameters showed that urea hydrolysis was nonspontaneous, and enthalpy and entropy changes were not significantly different among inhibitor treatments in five of the six soils. We conclude that the often-reported greater ammonia volatilization from URDI than URNBPT may not only be due to the persistence of ammonium in the presence of NI but also because NI reduced the inhibitory effect of NBPT on urea hydrolysis.

The impact of mineral soil cover fill on N2O emissions in peatland drained for agriculture

2020 ◽  
Author(s):  
Yuqiao Wang ◽  
Sonja Paul ◽  
Markus Jocher ◽  
Christine Alewell ◽  
Jens Leifeld
Keyword(s):  
Soil Moisture ◽  
Soil Cover ◽  
Mineral Soil ◽  
Experimental Period ◽  
Organic Soil ◽  
Soil N ◽  
Total N ◽  
Significant Difference ◽  
N Input ◽  
The Impact

&lt;p&gt;Drainage for agriculture has converted peatlands from a carbon sink to one of the world&amp;#8217;s major greenhouse gas (GHG) sources. In order to improve the sustainability of peatland management in agriculture, and to counteract soil subsidence, mineral soil coverage is becoming an increasingly used practice in Switzerland. Cover fills may change the GHG balance from the corresponding organic soil. To explore the effect of cover fill on soil N&lt;sub&gt;2&lt;/sub&gt;O emissions, we carry out a field experiment in the Swiss Rhine Valley and measure the soil &amp;#8211; borne N&lt;sub&gt;2&lt;/sub&gt;O exchange from two adjacent sites: drained organic soil without mineral soil cover (DN), and drained organic soil with mineral soil cover (DC). Mineral soil material was applied 12 years ago and varies in thickness between 20 &amp;#8211; 80 cm. Both sites have the identical farming practice (intensive permanent meadow). In our experiment, an automatic chamber system is used for collecting the N&lt;sub&gt;2&lt;/sub&gt;O at an interval of 3 h. Soil moisture, expressd as volumetric water content (VWC), is recorded every 10 min. After ten month (303 days) of continous measurement, the data reveal that: (1) The average N&lt;sub&gt;2&lt;/sub&gt;O emission from DN is higher than DC by a factor of 11 (11.24 &amp;#177; 3.46 &lt;em&gt;vs&lt;/em&gt; 0.97 &amp;#177; 0.22 mg N&lt;sub&gt;2&lt;/sub&gt;O-N m&lt;sup&gt;-2&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt;). Hence, mineral soil cover of organic soil seems to induce a strong reduction in N&lt;sub&gt;2&lt;/sub&gt;O emissions. (2) Exogenous N inputs (mineral N fertilizer and cow slurry) are the main drivers of N&lt;sub&gt;2&lt;/sub&gt;O emissions. N&lt;sub&gt;2&lt;/sub&gt;O peaks occured shortly after the N application and lasted for 2 to 3 weeks before returning to background N&lt;sub&gt;2&lt;/sub&gt;O emission. At the DC site post N- input N&lt;sub&gt;2&lt;/sub&gt;O emissions accounted for 68 % of the total N&lt;sub&gt;2&lt;/sub&gt;O emission over the whole measurement period. An equivalent of around 1 % of the exogenous N- input was emitted as N&lt;sub&gt;2&lt;/sub&gt;O. At the DN site, emission peaks after fertilization accounted for 79 % of the total N&lt;sub&gt;2&lt;/sub&gt;O emission, equivalent to around 13 % of the exogenous N- input. Background emissions between peak events shows no significant difference between DC (0.51&amp;#177; 0.15 mg N&lt;sub&gt;2&lt;/sub&gt;O-N m&lt;sup&gt;-2&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt;) and DN (2.73&amp;#177; 2.44 mg N&lt;sub&gt;2&lt;/sub&gt;O-N m&lt;sup&gt;-2&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt;). The comparison of peak and background fluxes tentatively indicates that higher average emission rates from the DN site are related directly to fertilization. Finally, surface soil characteristics (soil pH, bulk density, and soil N) changed after mineral soil cover, and soil moisture content differed between sites. During the experimental period, the mean daily soil moisture from DN site (24.1 % VWC &amp;#8211; 60.18 % VWC) is higher than DC site (20.17 % VWC &amp;#8211; 51.26 % VWC). In summary, our data from this first experimental period suggest that mineral soil cover fill could strongly reduce the N&lt;sub&gt;2&lt;/sub&gt;O emission from drained organic soil, and may therefore be an interesting GHG mitigation option in agriculture.&amp;#160;&amp;#160;&lt;/p&gt;

scholarly journals Dried Pig Manure from a Cogeneration Plant as a Fertilizer for Nitrate Vulnerable Zones

Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 46 ◽  
Author(s):  
Mercedes Sánchez-Báscones ◽  
Juan Antolín-Rodríguez ◽  
Carmen Bravo-Sánchez ◽  
Jesús Martín-Gil ◽  
Pablo Martín-Ramos
Keyword(s):  
Crop Yields ◽  
Block Design ◽  
Nitrification Inhibitor ◽  
Pig Manure ◽  
Mineral Fertilizers ◽  
Agricultural Practice ◽  
Mineral Fertilization ◽  
Good Agricultural Practice ◽  
Four Blocks ◽  
Vulnerable Zones

Nitrate vulnerable zones (NVZs) are areas considered to be at high risk of water pollution due to an excess of nitrates and, according to European regulations, codes of good agricultural practice are to be implemented by farmers, such as reducing doses of the applied fertilizers, or the use of fertilizers that minimize nitrate leaching. In this work, the influence of organic fertilization with dried pig manure (DPM) as compared to mineral fertilization with ammonium sulfate nitrate with 3,4-dimethylpyrazole phosphate nitrification inhibitor was studied in a barley crop planted in a NVZ in Fompedraza (Valladolid, Spain). Organic and mineral fertilizers were applied at different rates (85, 133 and 170 kg N·ha−1·year−1 vs. 90 and 108 kg N·ha−1·year−1, respectively) over a three-year period, in a randomized complete block design with six treatments and four blocks. DPM-based fertilization resulted in a 65% increase in crop yield as compared to the control soil, reaching 1800 kg·ha−1 for an application rate of 85 kg N·ha−1·year−1. Higher DPM rates were found to increase the electrical conductivity and assimilable phosphorus, potassium, magnesium and organic matter contents, but did not lead to yield enhancements. Final nitrate and ammonium concentrations were lower than 10 mg·kg−1 and 20 mg·kg−1, respectively, and no increase in soil salinity or heavy metal pollution was observed. DPM fertilization should be supplemented with small doses of inorganic fertilizers to obtain crop yields similar to those attained with mineral fertilization.

EFFECT OF MANURE AND P FERTILIZER ON PROPERTIES OF A BLACK CHERNOZEM IN SOUTHERN SASKATCHEWAN

1986 ◽  
Vol 66 (4) ◽  
pp. 601-614 ◽  
Author(s):  
C. A. CAMPBELL ◽  
V. O. BIEDERBECK ◽  
F. SELLES ◽  
M. SCHNITZER ◽  
J. W. B. STEWART
Keyword(s):  
N Mineralization ◽  
Crop Yields ◽  
Biological Properties ◽  
Microbial Biomass C ◽  
Net N Mineralization ◽  
Soil N ◽  
Total N ◽  
Soil C ◽  
Soil P ◽  
P Fertilizer

The effects of application of manure and P fertilizer on wheat yields in a fallow-wheat-wheat rotation on a Black Rego Chernozemic clay soil have been studied for 36 yr. The objective of this study was to identify the effects of manure on soil characteristics that could be related to the reported progressive yield increases over time and an apparent improvement in soil tilth. Soil samples were taken in 1982 from the check (no treatment), and from treatments receiving 13.4, 20.2 and 26.9 t ha−1 of manure applied each fallow year, and 112 kg ha−1 of seed-placed 11-48-0 applied to wheat after summerfallow. Soil physical and P-related parameters were determined for depth increments to 30 cm; the total-N and 15N data to 90 cm; other data were for the 0- to 7.5-cm depth. Manure had no effect on bulk density or hydraulic conductivity. However, it increased the total C and humic acid (HA) content of the soil, the percent of soil C as HA-C, the C concentration in humin, and the percent of total soil N as humin-N. Manure significantly increased the percent of HA-N but not humin-N present as amino acid and amino sugar-N, but increased amino acids and the amino sugars in the humin hydrolysate. The net rate of N mineralization and the available forms of inorganic P were all increased significantly by manure. The natural 15N-abundance technique showed that a significant though small proportion of soil N was derived from manure. Manure had no effect on soil microbial biomass C and N, soil respiration, and the quantity of potentially mineralizable N. Applied P had no effect on N-related parameters measured; its effect on available P was not measured. It was concluded that manure increased crop yields by improving the N- and P-supplying power of the soil, and improving the physical environment of the soil through its effects on the humic colloids. Key words: Humic substances, soil P fractions, soil biological properties, natural 15N abundance, net N mineralization

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