Mineral NPK Fertilizer Research Articles

Pig slurry as a nutrient source in wheat/corn succession

ABSTRACT Wheat and corn are important grains in the agricultural scenario of Brazil, and demand adequate supply of nutrients, particularly nitrogen, in crop succession. The use of pig slurry (PS) as a full and/or partial alternative to mineral fertilization in crop areas has been identified as an important alternative for the disposal of this waste. Therefore, the objective of this study was to evaluate the utilization of PS as fertilizer in wheat/corn succession under some plant parameters and grain yield. The experiment was conducted under field in randomized block design with four replications and five treatments, three with PS (40, 80, 160 m³ ha-1) and two controls (no fertilization and mineral NPK fertilization), which were applied manually in the soil shortly after sowing the crops. The application of PS proved to be a significant source of nutrients in wheat/corn succession. In comparison to NPK fertilization, this increase was only of 5.4% and 4.7% for wheat and corn, respectively. PS is an efficient alternative and it can be used as a source of these nutrients in wheat/corn succession, and the use of 80 m3ha-1 provides satisfactory results for all evaluated variables.

Effect of Some Different Sourses of Organic Fertilizers and Seaweed Extract on Growth and Essential Oil of Sweet Fennel (Foeniculum vulgare Mill.) Plants.

This work was carried out during the two successive winter seasons of 2014/ 2015 and 2015/ 2016 at Meet Assas village, (Private Farm) Gharbieh Governorate, Egypt, on sweet fennel plants, to investigate the utilization of some different sources and rates of organic manure (chicken and farmyard manure) at 50 and100 % of recommended rate / fed., foliar fertilizer of seaweed extracts ( without and with 2 g / liter) compared with mineral NPK fertilizer at 50 and 100 % of recommended rate /fed., and their interaction on plant growth, yield (bulb and fruit fennel) and chemical composition. The application of farmyard manure at 100 % with seaweed extract showed increased growth compared to the chicken manure at 100% or inorganic fertilizer at 100% with seaweed extracts in the plant fresh and dry weight, plant height, number of leaves, bulb and fruits yield, as well as essential oil. Similarly, chemical parameters have also shown increased from farmyard manure over the inorganic fertilizers. Thus our study provides the evidence for using seaweed extract with organic fertilizer like farmyard manure by farmers to have better yield to produce from bulbs and fruits, organic manure is easy available, environmentally safe and cost effective in sweet fennel plants

Efficiently Treated Sewage Sludge Supplemented with Nitrogen and Potassium Is a Good Fertilizer for Cereals

AbstractSewage sludge contains phosphorus (P), nitrogen (N), potassium (K) and organic matter in both soluble and particulate forms. However, agricultural use of sludge is limited because of possible problems due to hygiene, heavy metals, inner quality variation and non‐balanced ratios of nutrients. We tested sustainable fertilization of cereals with (i) urea‐spiked granulated sludge, (ii) composted anaerobic sludge digestate, (iii) dried (dewatered), anaerobic thermophilic digestate sludge mixture and (iv) dried (dewatered) sludge. The sludge products were applied to barley and wheat with variable combinations of N and K supplements in Nordic climate. Sludge products supplemented with N and K and mineral NPK fertilizers containing soluble 70 kgN ha−1 achieved barley dry yields above 3500 kg ha−1. The grain N content was 22·3 g kg−1 in barley fertilized with granulated sludge fortified with NK (soluble N 83 kg ha−1), while grain N content was 20 g kg−1 when fertilized with 90 kgN ha−1 NPK. The wheat dry yields were 2890 and 2850 kg ha−1 fertilized with granulated sludge fortified with NK when soluble N was 49 kg ha−1 and NPK with 110 kgN ha−1 of these grains containing N 29·2 and 29·0 g kg−1. The results mean that correctly treated and formulated sludge products can be used. The risks caused by enteric microorganisms or heavy metals could be managed. The residual nitrate concentrations in soil were low. Sludge products could be developed by optimizing nutrient ratios and their structure. Sludge producers should provide farmers with detailed physicochemical data about each sludge portion. Copyright © 2016 John Wiley & Sons, Ltd.

Potential Application of Glomus Intraradices (AMF) and Different Isolates of PGPR (Biotol) to Enhance the Yield and Quality of Wheat Grown in The Field in Calcareous Soil Under Different Salinity Levels

Two field experiments were carried out at the farm of Nubaria Agricultural Research Station during the two winter seasons of 2012/2013 and 2013/2014, to study the effect of the arbuscular mycorrhizal fungus, Glomus intraradices and the plant growth promoting rhizobacteria (Biotol) on growth, yield parameters and chemical contents of two wheat cultivars (Sakha 93 and Gemmeza 9) grown in calcareous soil under four levels of soil salinity and four rates of NPK mineral fertilizers. Results indicated that, wheat plants inoculated with AMF and Biotol together significantly decreased Na shoot content (mg/kg), increased NPK uptake, proline and salicylic acid contents, chlorophyll and grain protein at all the tested salinity levels compared to un-inoculated plants. Under normal salinity level (≤4 dSm-1), dual inoculation with AMF and Biotol resulted total grain yield to 6.5 and 6.7 t/ha for Sakha 93 and Gemmeza 9, respectively, in the presence of NPK100%with a percentage increases of 41 and 29 more than un-inoculated plants. Results clearly indicated that, proline and Salicylic acid content were significantly increased in dual inoculated plants in Sakha 93 comparing to Gemmeza 9 under soil salinity up to 8 dSm-1. The percentage increases were 38.6 and 37.54 for proline and 192.57 and 135.42 for salicylic acid in case of Sakha 93 and Gemmeza 9, respectively, in the presence of NPK75% and soil salinity 8-12 dSm-1. No significant differences were observed among plants inoculated with G. intraradices and PGPR either in the presence of 75 or 100% of the recommended dose of NPK. Summing up it could be concluded that inoculation with AMF and Biotol successfully improve the growth, yield and salt stress tolerance of the tested cultivars in calcareous soil.

Effect of Mineral and Bio- Fertilization on Vegetative Growth and Flowering of Anthurium andreanum L. Plants under Greenhouse Condition

The present study was designed to estimate the effect of mineral fertilizer NPK (19:19:19) at 0.0, 5.0, 10.0 and 15.0 g / plant, bio-fertilizer (active dry yeast) at levels 0.0, 2.0, 4.0, and 6.0 g/ l and their combination on growth, flowering and leaves chemical composition of Anthurium andreanum, L. plants. The experiment was carried out during 2010 and 2011 growing seasons in Alexandria university's nursery. The results indicated that planting Anthurium andreanum, L. under greenhouse conditions with applying 10 g / pot of mineral NPK monthly during the growing seasons, combined with active dry yeast at 6 g / l improved the vegetative growth and flowering parameters ( plant height, number of leaves, leaf area, leaf dry weight, number of flowers / plant, flower dry weight and leaf chemical composition parameters [ total chlorophyll and mineral content (N, P and K %)]. These results can be used for improving Anthurium fertilizing programs for economic production.

RESPONSE OF MORINGA OLEIFERA TO ORGANIC BIOFERTILIZERS AND MINERAL NPK FERTILIZATIONS

This investigation was conducted to investigate the response of Moringa oleifera to compost fertilization at four levels (0, 5, 10 and 15 ton/fed) and bio. and/or mineral NPK treatments [(control, 100% NPK, 75% NPK + phosphorein + Minia Azotein, 50% NPK + phosphorein + Minia Azotein and phosphorein + Minia Azotein (Bio)] on vegetative growth traits, yield and pigments. The obtained results indicate that, plant height, stem diameter, number of branches, number of pods/plant, number of seeds/pod and seed yield/plant, as well as, pigments were gradually increased by increasing the levels of compost fertilizer. All bio. and/or mineral NPK fertilization treatments significantly increased all the previous parameters. Bio. + 75% NPK dose followed by mineral NPK (full dose) treatments were more effective in this concern. The highest values for vegetative growth traits, yield and yield components and pigments were obtained due to compost at 15 ton/fed in combination with bio. + 75% NPK dose.

Study on some soil quality changes obtained from long-term experiments

Agricultural practice often causes soil structure degradation and as a result it leads to changes in soil fertility and quality. The aim of this study was to compare soil aggregate stability (SAS) and soil organic matter (OM) quantity and quality in different systems of soil management. Three adjoining long-term experiments established on Chernozem were chosen; they were all set up in different years with different crop rotations and comparable fertilization treatments: control (without fertilization); NPK; manure; NPK + manure; N + manure; OM and NPK + OM. SAS was statistically significantly lower in the trial with the highest proportion of cereals in the crop rotation. Differences among the fertilization treatments were noticeable, but not significant; the lowest SAS was observed at treatments with the mineral NPK fertilization. Significant correlation was found out between SAS and C/N ratio (R = -0.571; P < 0.05) and between SAS and soil pH (R = 0.30; P < 0.05). Further, the individual trials differed in soil pH. A significant positive influence of the treatment NPK + manure was observed in the content of hot water-extractable carbon (Chwl) and total soil organic carbon and nitrogen. The significant correlation between the 3000-2800/cmpeak area of fourier transform infrared (FTIR) spectra and labile organic compounds in soil (Chwl) was confirmed.

Energizing marginal soils – The establishment of the energy crop Sida hermaphrodita as dependent on digestate fertilization, NPK, and legume intercropping

Growing energy crops in marginal, nutrient-deficient soils is a more sustainable alternative to conventional cultivation. The use of energy-intensive synthetic fertilizers needs to be reduced, preferably via closed nutrient loops in the biomass production cycle. In the present study based on the first growing season of a mesocosm experiment using large bins outdoors, we evaluated the potential of the energy plant Sida hermaphrodita to grow in a marginal sandy soil. We applied different fertilization treatments using either digestate from biogas production or a commercial mineral NPK-fertilizer. To further increase independence from synthetically produced N-fertilizers, the legume plant Medicago sativa was intercropped to introduce atmospherically fixed nitrogen and potentially facilitate the production of additional S. hermaphrodita biomass. We found digestate to be the best performing fertilizer because it produced similar yields as the NPK fertilization but minimized nitrate leaching. Legume intercropping increased the total biomass yield by more than 100% compared to S. hermaphrodita single cropping in the fertilized variants. However, it negatively influenced the performance of S. hermaphrodita in the following year. We conclude that a successful establishment of S. hermaphrodita for biomass production in marginal soils is possible and digestate application formed the best fertilization method when considering a range of aspects including overall yield, nitrate leaching, nitrogen fixation of M. sativa, and sustainability over time.

Long-term effects of alternative and conventional fertilization II: Effects on Triticum aestivum L. development and soil properties from a Brazilian ferralsols

The influence of long-term fertilization on plant development and soil properties was investigated. Soil samples were taken from a long-term field experiment which was conducted for 5 years to explore the effect of three treatments: control (non-fertilization), conventional (mineral fertilizers—NPK), and alternative (organic fertilizers—farmyard manure). The highest values of plant yield and soil properties were found in the alternative fertilization system after the thirty year of its utilization. Conventional fertilization showed positive effects until the second year of its utilization where enhanced soil fertility (total nitrogen and available phosphorous content) and plant development (plant yield, plant dry biomass, plant phosphorous concentration, and plant nitrogen concentration). After the thirty year the conventional fertilization system showed lower values for these studied variables compared to alternative fertilization system. Our findings suggest that inputs of organic matter source can change positively the wheat growth and soil fertility, and these results highlight the importance of considering the long-term effect of mineral and organic fertilizers on these variables.

Residual value of inorganic fertilizer and farmyard manure for crop yields and soil fertility after long-term use on a loam soil in Norway

Mineral NPK fertilizer and manure have been compared since 1922 in a ley–arable rotation. During 1982–2003, cattle manure at 20–60 Mg ha−1 year−1 yielded 10–20 % less than mineral fertilizer at 100 kg N:25 kg P:120 kg K ha−1 year−1. The higher manure rates gave large nutrient surpluses. Both manure and mineral fertilizer had increased soil organic carbon (SOC), by 11.3 and 3.4 Mg ha−1 in 1996. In order to study possible residual effects, no manure was applied in 2004–2007 and mineral fertilizer was withheld from some NPK plots. Effects on yield and nutrient uptake were evaluated in relation to plots with no nutrient supply since 1922 and plots still receiving 100 kg N, 25 kg P and 120 kg K ha−1 annually. No residual response of mineral fertilizer was found, but previous manure use gave large effects. The latter yields remained around 85 % of those obtained with mineral fertilizer. Previous use of both mineral fertilizer and manure still increased available soil nutrients and pH in 2007. Differences between treatments in SOC had by then declined slightly, to 9.7 and 2.8 Mg ha−1 for manure and mineral fertilizer respectively, relative to the unfertilized control. Manure and fertilizer applications were resumed in 2008, except at the highest previous manure rate, where mean residual responses up to 2014, relative to the unfertilized control, amounted to 55 % higher yield and increases in nutrient uptake of 47 kg N, 8 kg P and 53 kg K ha−1.

Evaluating crop response and environmental impact of the accumulation of phosphorus due to long-term manuring of vertisol soil in northern China

The availability of soil phosphorus (P) is one of the key factors that regulate crop productivity. Fertilization practices with P fertilizers carry a high risk of non-point environmental pollution due to water run-off and leaching. The present work discusses data from a 29-year (1982–2011) fertilization experiment with wheat–soybean rotation. Its aim was to quantify and evaluate the dynamic of soil P availability in relation to P accumulation, crop yield, and environmental safety in northern China. This study included six treatments with four field replicates: CK (no fertilizer), NPK (mineral fertilizers), 1/2SNPK (mineral fertilizers plus 50% wheat straw return), SNPK (mineral fertilizers plus 100% wheat straw return), PMNPK (mineral fertilizers plus pig manure), and CMNPK (mineral fertilizers plus cattle manure). Continual additional application of farmyard manure (i.e., PMNPK and CMNPK) produced significantly (P<0.01) better soil total P and Olsen-P than NPK treatment, and both factors showed increasing trends. However, straw incorporation (i.e., 1/2SNPK and SNPK) had no effect on soil P or Olsen-P. There were significant positive correlations between P budget and increase in Olsen-P and total P. These correlations indicated that, with each 100kgha−1 of P budget, there were about 1.0–1.1 and 22.5–26.0mgkg−1 increases in Olsen-P and total P for the straw incorporation treatments, whereas there were 5.7–5.9 and 26.5–30.8mgkg−1 increases in Olsen-P and total P for use of manure. Average P activation coefficients for soil Olsen-P in the PMNPK and CMNPK treatments increased sharply by 87.2% and 121.3% compared to the NPK treatment (P<0.01). Two segment regression analyses indicated there to be observable changes in the relationships between Olsen-P and relative crop yield, and in Olsen-P and soluble-P, indicating critical Olsen-P levels of 11mgkg−1 for crop yield, and 18mgkg−1 for soluble P, respectively. In conclusion, much more P is available in the soil under long-term farmyard manure than crop straw incorporation when the amount of P accumulation is uniform. Long-term, continuous, excessive use of farmyard manure to increase crop yield is not sustainable and has a high risk of P environmental pollution. The incorporation of crop straw is a recommended means of managing which decreases the risk of P environmental pollution without compromising crop productivity of vertisol soil in northern China.

Effects of long-term (23 years) mineral fertilizer and compost application on physical properties of fluvo-aquic soil in the North China Plain

The influence of compost and mineral fertilization on soil organic carbon (SOC) and physical properties varied greatly in previous studies because of differences in site conditions such as climate and soil. This study was conducted as a long-term (1989–2012) field experiment to evaluate the effects of mineral fertilization and compost application on SOC content and some physical properties of an intensively cultivated sandy loam soil in the North China Plain. The experiment consisted of seven treatments: organic compost (OM); half organic compost plus half mineral fertilizer NPK (1/2OM1/2NPK); mineral fertilizer NPK (NPK); mineral fertilizer NP (NP); mineral fertilizer PK (PK); mineral fertilizer NK (NK); and unfertilized control (CK), each with four replicates. Relative to CK, the SOC content was higher in all of the compost and mineral fertilizer treatments, but increments in SOC under the compost application treatments were higher than mineral fertilization application. Compost application (OM, 1/2OM1/2NPK) decreased soil bulk density and increased total porosity significantly in comparison with that in the CK plots. Soil bulk density and total porosity for the mineral fertilization treatments, except NP, did not significantly differ from CK. The lowest penetration resistance at 0–20cm soil depth was observed in the NK plots, and the highest penetration resistance was found in the CK plots. Compost application increased the total amount of water-stable macro-aggregates (>0.25mm); however, MWD was not significantly affected by compost application. The MWD in the NK treatment was lower than in CK by 0.2mm, while its variation among NPK, OM, 1/2OM1/2NPK, NP, PK, and CK was not significant. The compost- and mineral fertilizer-treated soil had 34.6–91.7% higher volume of macropores than the CK soil. The OM and 1/2OM1/2NPK-treated soil had a significantly higher proportion of small pores (<3.3μm), and the mineral fertilizer-treated soil did not differ from CK. The hydraulic conductivity in the balanced fertilization plots (OM, 1/2OM1/2NPK, NPK) tended to be higher than in the unbalanced fertilization treatments (NP, PK, and NK) and CK. The results indicated that supplementation with organic manure such as compost is more beneficial to enhance soil fertility and maintain the sustainability of crop production in the North China Plain.

Long-term effects of alternative and conventional fertilization I: Effects on arbuscular mycorrhizal fungi community composition

The influence of long-term fertilization on arbuscular mycorrhizal fungi community composition was investigated. Soil samples were taken from a long-term field experiment which was conducted for 5 years to explore the effect of three treatments: control (non-fertilization), conventional (mineral fertilizers—NPK), and alternative (organic fertilizers—farmyard manure). The highest values of AMF community composition were found in the alternative fertilization system after the thirty year of its utilization. After the thirty year the conventional fertilization system showed lower AMF diversity compared to alternative fertilization system. In conclusion the alternative fertilization system enhanced mycorrhizal effectiveness that contributes to increase wheat growth after a long-term experiment. Our findings also suggest that inputs of organic matter source can change positively the AMF community composition, and these results highlight the importance of considering the long-term effect of mineral and organic fertilizers on the AMF community diversity. Thus, the long-term utilization of an alternative fertilization system with continuous input of organic matter may exploit positive situations of jointly beneficial biotic and abiotic conditions.

Long-term effects of alternative and conventional fertilization on macroarthropod community composition: a field study with wheat (Triticum aestivum L) cultivated on a ferralsol

The influence of long-term fertilization on macroarthropod community composition from a field study with wheat (Triticum aestivum) was investigated. Soil samples were taken from a long-term field experiment which was conducted for 5 years to explore the effect of three treatments: control (non-fertilization), conventional (mineral fertilizers—NPK), and alternative (organic fertilizers—farmyard manure). The highest values of macroarthropod community composition were found in the alternative fertilization system after the 30 years of its utilization. After 30 years, the conventional fertilization system showed lower values for these studied variables compared to alternative fertilization system. Our findings suggest that inputs of organic matter source can change positively the macroarthropod community composition, and these results highlight the importance of considering the long-term effect of mineral and organic fertilizers on the diversity of this biological component and their effect on wheat growth and soil fertility. Thus, the long-term utilization of an alternative fertilization system with continuous input of organic matter may exploit positive situations of jointly beneficial biotic and abiotic conditions.

Long-term effect of residue return and fertilization on microbial biomass and community composition of a clay loam soil

SUMMARYA field study was carried out to examine the response of microbial communities of a clay loam soil to long-term (30 years) effects of residue return and fertilization. The experimental design was a split-plot arrangement of treatments, consisting of three residue treatments (crop residues returned at rates of 0, 2500 and 5000 kg/ha) in combination with eight fertilization treatments (control, no fertilizer; N, mineral nitrogen (N) fertilizer; P, mineral phosphorus (P) fertilizer; K, mineral potassium (K) fertilizer; NP, mineral NP fertilizer; NK, mineral NK fertilizer; PK, mineral PK fertilizer; and NPK, mineral NPK fertilizer). Soil microbial communities were characterized by phospholipid fatty acid analysis. Results indicated that the more crop residues were returned, the lower ratio of fungi to bacteria was observed. However, soil microbial biomass was only found to be significantly higher in plots with residues returned at a rate of 5000 kg/ha but not 2500 kg/ha. This suggested there was a threshold for microbial biomass to increase under residue return for the clay loam soil studied. The fertilization effect on soil microbial biomass gradually decreased with increases in the amount of crop residues returned. A significant composition change was observed under N fertilization. Structural equation modelling indicated that soil microbial communities were influenced directly by residue return and indirectly by residue-induced change in ratio of carbon to N and fertilization-induced change in soil pH.

The Response of Sorghum, Groundnut, Sesame, and Cowpea to Seed Priming and Fertilizer Micro-Dosing in South Kordofan State, Sudan

This study was undertaken with the objective of evaluating micro-dosing of mineral fertilizer combined with seed priming in sorghum, groundnut, sesame, and cowpea. On-station and on-farm trials were conducted for two consecutive seasons (2009/2010 and 2010/2011) at Al-Tukma village (12°00′57.60′′ N and 29°46′12.15′′ E) in South Kordofan State, 15 km southeast of Dilling city. Heavy cracking clay soil is the dominant soil type in the region with low fertility. The experiments for each crop consisted of two priming levels (primed seeds vs. non-primed) and four micro-doses of NPK mineral fertilizer (0, 0.3, 0.6 and 0.9 g per planting pocket or hole). On-farm trials in 15 fields consisted of control, seed priming, and seed priming + micro fertilizer (0.3 g/planting hole). Data collected included plant vigor, stand count, plant height, grain and straw yield, seed weight, and other relevant agronomic traits. This study shows that it is possible to increase productivity of sorghum, sesame, groundnut, and cowpea in the semi-arid cracking clay of South Kordofan State at a low cost and with a moderate risk for farmers through seed priming and micro-dosing of fertilizers. Seed priming combined with micro-dosing NPK mineral fertilizer of 0.9 g was the best treatment for plant establishment, seedling vigor, grain yield, and hay yield in sorghum and groundnut, whereas the combination of seed priming and 0.3 g micro-doing of fertilizer was the best in sesame. Seed priming and micro-dosing of fertilizer of 0.6 g was the best combination for cowpea. On-farm trial results indicated that priming alone and priming combined with fertilizer application significantly increased the yields of sorghum, groundnut, and cowpea over the control (P = 0.01). Of the crops tested, groundnut responded most favorably to micro-dosing and seed priming, with a value to cost ratio (VCR) of 26.6, while the highest VCR for sorghum, sesame, and cowpea was 12.5, 8.0 and 4.4, respectively. For the best productivity and profitability, we recommend using seed priming in combination with the micro-dosing of 0.9 g/hole of 15:15:15 NPK fertilizer for sorghum and groundnut, of 0.3 g/hole for sesame, and of 0.6 g/hole for cowpea grown in the semiarid South Kordofan State of Sudan.

Mechanisms of soil N dynamics following long-term application of organic fertilizers to subtropical rain-fed purple soil in China

In this study, a 15N tracing incubation experiment and an in situ monitoring study were combined to investigate the effects of different N fertilizer regimes on the mechanisms of soil N dynamics from a long-term repeated N application experiment. The field study was initiated in 2003 under a wheat-maize rotation system in the subtropical rain-fed purple soil region of China. The experiment included six fertilization treatments applied on an equivalent N basis (280 kg N ha−1), except for the residue only treatment which received 112 kg N ha−1: (1) UC, unfertilized control; (2) NPK, mineral fertilizer NPK; (3) OM, pig manure; (4) OM-NPK, pig manure (40% of applied N) with mineral NPK (60% of applied N); (5) RSD, crop straw; (6) RSD-NPK, crop straw (40% of applied N) with mineral NPK (60% of applied N). The results showed that long-term repeated applications of mineral or organic N fertilizer significantly stimulated soil gross N mineralization rates, which was associated with enhanced soil C and N contents following the application of N fertilizer. The crop N offtake and yield were positively correlated with gross mineralization. Gross autotrophic nitrification rates were enhanced by approximately 2.5-fold in the NPK, OM, OM-NPK, and RSD-NPK treatments, and to a lesser extent by RSD application, compared to the UC. A significant positive relationship between gross nitrification rates and cumulative N loss via interflow and runoff indicated that the mechanisms responsible for increasing N loss following long-term applications of N fertilizer were governed by the nitrification dynamics. Organic fertilizers stimulated gross ammonium (NH4+) immobilization rates and caused a strong competition with nitrifiers for NH4+, thus preventing a build-up of nitrate (NO3−). Overall, in this study, we found that partial or complete substitution of NPK fertilizers with organic fertilizers can reduce N losses and maintain high crop production, except for the treatment involving application of RSD alone. Therefore, based on the N transformation dynamics observed in this study, organic fertilizers in combination with mineral fertilizer applications (i.e. OM, OM-NPK, and RSD-NPK treatments) are recommended for crop production in the subtropical rain-fed purple soils in China.

Effects of meat bone meal as fertilizer on yield and quality of sugar beet and carrot

Meat and bone meal (MBM) is a by-product of the meat industry and is an important pathway for recycling of N and P. MBM contains about 8% N, 5% P, 1% K and 10% Ca. Field trials compared the effects of MBM and mineral fertilizer on yield and quality of sugar beet (2008-2009) and carrot (2010-2011) in Finland. MBM fertilisation of sugar beet grown on clay loam and sandy clay soil gave 11.4% (2008) and 19.6% (2009) lower yields than mineral fertilizers. The lower root yield in 2008 was compensated by higher extractable sugar content and lower amino-N, K and Na in root but no such compensation in root quality was detected for 2009. Mixing MBM with mineral NPK fertilizers had similar effects as MBM-alone. MBM (80 kg N ha-1 2010 and 60 kg N ha-1 2011) together with K fertilizer (Patentkali®, 180 kg K ha-1) were applied for carrot to a fine sandy till soil in 2010 and sandy loam in 2011. MBM alone gave 14% lower total and marketable root yield than mineral fertilization. The lower yield was compensated by improved quality, lower NO3- content in the carrot and good storability. Adding extra fertilizer during growth or separating fertilization applications had no effect on root yield or quality. MBM performed in these cases mainly as an organic N fertilizer. The N supply from MBM is not sufficient for achieving same yields as with mineral fertilizers. The relative N efficiency of total N of MBM was 83% that of mineral fertilizers. MBM should be targeted on soils with low P status.We conclude that MBM is a reasonably competitive alternative to mineral fertilizers, and as a recycled fertilizer it is a good option for organic production.

Long-term application of organic manure changes abundance and composition of ammonia-oxidizing archaea in an acidic red soil

Ammonia-oxidizing archaea (AOA) have more importance in ammonia oxidation than ammonia-oxidizing bacteria (AOB) in acidic red soils. The aim of this study was to investigate if the abundance and composition of AOA could be altered by long-term application of organic manure in an acidic red soil. The abundance and composition of AOA were evaluated by polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) targeting archaeal amoA genes after long-term (24-year) application of mineral fertilizer and/or organic manure. The treatments were: non-fertilized control, mineral nitrogen (N) fertilizer only, mineral N, phosphorus (P) and potassium (K) fertilizer only, organic manure only, and organic manure plus mineral NPK fertilizer. The abundance of archaeal amoA genes was significantly increased after the long-term application of organic manures, either with or without mineral NPK fertilizer. So were the Shannon and Richness diversity indices of AOA deduced from the DGGE patterns. Phylogenetic analyses showed that most of the AOA sequences from various fertilization treatments were affiliated with group 1.1b thaumarchaea and only one with the group 1.1a-associated thaumarchaea. Nitrification potential was significantly increased after the long-term application of organic manures in comparison with the non-fertilized control. Our results strengthened the importance of organic manure in promoting the growth of AOA and thus nitrification potential in the acidic red soils.

Improving grain yield and reducing N loss using polymer-coated urea in southeast China

The efficiency of classical mineral NPK fertilizers is usually low because a major part of these fertilizers does not reach plant roots and ends up polluting groundwaters with nitrates and phosphates. Recently, a novel polymer-coated urea made from recycled plastics was proposed to enhance N availability in cereal production. To evaluate the efficiency of this polymer for rice production, we set up field plots, microplots, and pot experiments with 15N tracing. We compared rice yield, N uptake, and N loss between conventional three split applications of urea and a single basal application of four derivatives from the polymer-coated urea. The four derivatives included a blend with 70 % of N from 6 % (w/w) coated urea and 30 % from urea and three coated urea fertilizers with 6, 8, and 12 % coating at an identical N application rate during two rice-growing seasons. Results show that 6 % coated urea improved 15N recovery, reduced 15N loss, and increased grain yield slightly due to an initial 15N burst occurring at high field temperatures after basal fertilization; 8 or 12 % coated urea better met plant N demand from transplanting to heading, greatly enhanced 15N recovery, and decreased 15N loss and NH3 volatilization. Nevertheless, unlike a significant increase of yield for 12 % coated urea, 8 % coated urea did not increase yield due to 15N release and excessive 15N uptake by plants at ripening. Overall, our findings show that a single basal polymer-coated urea application improves N use efficiency and reduces N loss in rice agroecosystem.