NPK Chemical Fertilizer Research Articles

Impacts of nano- and non-nanofertilizers on potato quality and productivity

Today, to achieve sustainable agriculture with maximum yield and minimum environmental risks, the use of nanofertilizers has riveted ample consideration. Field experiments were conducted during binary season of 2016 and 2017 at Research Farm, Faculty of Agriculture, Minia University, Egypt to estimate whether NPK nanofertilizers applied in equivalent or lower rates could replace recommended levels of NPK chemical fertilizers in potato farming systems without retrograde effects upon yield production or quality. Impacts of recommended rates of NPK chemical fertilizers (control treatments) compared to NPK nanofertilizers in equivalent or lower rates (100%, 50% and 25%), foliar or soil applied on potato productivity and quality were studied.Compared with control treatments, plots receiving foliar application of NPK nanofertilizers at 50% or 25% of recommended level showed higher values of economic yield (23.59-ton ha−1), starch rates (79.62%), NPK nutrient use efficiency (67.74, 278.92, 118.54 kg potato/kg nutrient), harvest index (59.24%) and only lower potato nitrate content (1.15 g kg−1) as a harmful indicator. Among all treatments, foliar application of NPK nanofertilizers at 50% rate was found to be the most economical treatment as it gave highest potato yield and quality plus highest profit: cost ratio of potato production. This research recommends foliar application of nanofertilizers in potato production to increase production and quality compared to soil applications. As yet, using lower rates of nanofertilizers as foliar application in the present study proved to be an eco-friendly environmental and economic alternative to recommended rates of chemical fertilizers with significant increase in potato productivity and quality.

Partial substitution of chemical fertilizers with organic amendments increased rice yield by changing phosphorus fractions and improving phosphatase activities in fluvo-aquic soil

The aim of this study was to investigate the effect of combined use of chemical fertilizers with wheat straw and swine manure on rice yield and phosphorus (P) fractions distribution. We selected two field experiments, both located in Hefei, Anhui province of China. We named these experimental sites as HF-1 and HF-2. The experiments HF-1 and HF-2 were initiated on 2013 and 2015 respectively in fluvo-aquic soil. Treatments included CK (no fertilizer), NPK (chemical fertilizers), NPKS (chemical fertilizers plus wheat straw), and NPKM (chemical fertilizers plus swine manure at HF-1, and chemical fertilizers plus fermented wheat straw at HF-2). Results showed that NPKS and NPKM treatments increased grain yield, P use efficiency (PUE), P recovery efficiency, and partial factor productivity, and decreased apparent P balance compared with CK and NPK at both sites. NPKS and NPKM improved pH, organic matter, and nutrient contents in surface soil (0–20 cm) and also improved pH and organic matter content in sub-surface soil (20–40 cm), compared with CK and NPK treatments. Olsen P content in both soil depths was highest under NPKM, but NPKS had lower Olsen P content in sub-surface soil compared with that of NPK. Organic amendments changed P fractions and increased labile P and moderately labile P fractions, and decreased residual P compared with NPK. Organic amendments with chemical fertilizers also improved acid phosphomonoesterase and phosphodiesterase activities compared with chemical fertilization. In addition, path analysis showed relationship between soil properties and P mobility, and also explained soil properties influencing grain yield by changing PUE. Our results suggested that organic amendments improve crop yield through improving PUE by changing soil P fractions and increasing the phosphatase activities.

Short-Term Effects of Tillage Intensity and Fertilization on Sunflower Yield, Achene Quality, and Soil Physicochemical Properties under Semi-Arid Conditions

Inappropriate soil management practices and specific climatic conditions in semi-arid region cause loss of soil organic matter (SOM), decline soil fertility, and trigger soil erosion processes and desertification. A two-year field study was carried out to investigate the effects of tillage intensity and fertilizer regime treatments on the productivity of sunflower (Helianthus annus L.) and soil physicochemical properties in the semi-arid highland region in northwest Iran (37°31′ north (N), 46°53′ east (E)). Five fertilizer treatments were included under conventional (CT) or reduced tillage systems (RT): F1, no fertilizer application; F2, 20 t∙ha−1 farmyard manure (FYM); F3, 40 t∙ha−1 FYM; F4: 20 t∙ha−1 FYM + 50% of the recommended dose of nitrogen–phosphorus–potassium (NPK) chemical fertilizer; F5: full dose of the recommended chemical NPK fertilizer. Results showed that utilization of FYM decreased bulk density (BD); its effects were more evident under the highest SOM content for the F2 and F3 treatments, whereas application of mineral fertilizer had no significant effect upon SOM content, and elevated levels of FYM preserved higher organic carbon contents in topsoil. The highest N, P, and K contents of the soil were obtained with FYM plus inorganic fertilizer application in the RT system. Hydraulic conductivity and soil moisture content were significantly improved by RT and FYM application. The highest root growth was observed for F3 and F4 under the RT system. The effect of fertilizer and tillage treatments was more pronounced during the second year. Traits related to growth and seed quality such as achene oil content, leaf area, and harvest index were enhanced by chemical fertilization in the CT system. The highest achene yield and oil percentage were recorded for plants grown with F3 and F4. The best option for enhancing sunflower productivity and quality in semi-arid, high-altitude environments is the application of organic fertilizers amended with reduced amounts of chemical fertilizers.

Small wetted proportion of drip irrigation and non-mulched treatment with manure application enhanced methane uptake in upland field

Methane oxidation in upland areas plays a critical role in the global methane budget. A three-year field experiment was conducted to investigate the effects of two soil surface treatments including soil covered with black plastic film mulch (BM) and non-mulched treatment (NM), three fertilizer treatments including chemical NPK fertilizer (CF), cattle manure (CM) and their combined application of 50% chemical NPK fertilizer and 50% cattle manure (CF+CM), and three soil wetted proportion levels under drip irrigation including: 35% (P1), 55% (P2) and 75% (P3) on methane oxidation in potato field in the arid area of northwestern China. Results showed that seasonal cumulative methane uptake value was 1.1–4.9 kg hm−2 in potato upland fields. BM treatment decreased seasonal cumulative methane uptake by 17%–50% compared to NM treatment through increasing average soil temperature by 2.0–2.5 °C, increasing average irrigation interval by 0–15% and its barricade effect of gas exchange. CM treatment increased seasonal cumulative methane uptake by 7%–9% and 14%–108% in contrast to CF+CM treatment and CF treatment, respectively, due to the low nitrogen content under CM treatment. Different soil wetted proportions didn't significantly affect methane oxidation, while 35% of soil wetted proportion had the greatest methane oxidation rate. Methane flux was quadratically correlated (p = 0.001) to soil matric potential, and the optimal soil matric potential for methane oxidation was −24 kPa. In summary, this study investigated methane uptake in potato farmland contributing to methane flux budget estimation. Manure applied without mulch had more advantage on methane oxidation, and a soil wetted proportion level of 35% was recommended in this study, for favorable for methane oxidation.

The effects of biological, chemical, and organic fertilizers application on root growth features and grain yield of Sorghum

To investigate the effect of some biological and chemical fertilizers on the root physiological and growth indexes and also Sorghum grain yield, this study was carried out in randomized complete block design with three replicates. The treatments of the study included (1) arbuscular mycorrhizal fungus Glomus mosseae + vermicompost, (2) mycorrhiza fungus + Nitroxin, (3) mycorrhiza fungus+ Rhizobium sp., (4) mycorrhiza fungus + NPK chemical fertilizer (40-40-20), (5) mycorrhiza fungus, and (6) control treatment. The highest root colonization rate and specific root length were observed in the co-inoculation with mycorrhiza + Nitroxin treatment. The other root growth parameters were observed at the mycorrhiza + vermicompost treatment. Also the highest rate of Sorghum physiological growth indexes root such as root area index and net assimilation rate were belonged to the co-inoculation of mycorrhiza + Nitroxin treatment. The highest root growth rate and root relative growth rate were obtained in the mycorrhiza + vermicompost treatment. So it can be concluded that biological fertilizers can be used as an appropriate alternative for chemical fertilizers in sustainable agriculture system.

Effects of long-term application of organic fertilizer on improving organic matter content and retarding acidity in red soil from China

Long-term fertilization causes declines in soil quality and crop yield, hindering current agricultural development. This paper is about the effect of long-term fertilization (20 years) in Hunan’s Qiyang County. It was found that chemical nitrogen, phosphorus, and potassium (NPK) fertilizer lowered soil pH by an annual average of 0.07, while organic fertilizer increased soil pH by about 0.04. Furthermore, organic fertilizer and chemical fertilizer both increased total soil organic carbon (SOC). Long-term chemical NPK and organic fertilizer increased straw and grain yield of wheat and maize to a greater extent than did other fertilization methods. Thus, our results suggest that mixing organic fertilizer with chemical NPK fertilizer should prevent soil acidification and elevate crop yield.

Effect of the fertilization and growth promoting microrganisms on Schizolobium parahyba

The objective of this work was to evaluate the effect of the chemical and biological fertilizing on the development of two varieties of Schizolobium parahyba, paricá and guapuruvú. The chemical fertilizer NPK 20-05-20 and the plant growth promoting microorganisms, Rhizobium sp. (Rhi) and Rhizophagus clarus (Arbuscular Mycorrhizal Fungus - AMF). The experimental design was a randomized complete block with five replicates and eight treatments. Forty-six day old seedlings of each variety were planted in pits containing hydroretent gel. Then the treatments were added: 1. Control; 2. Rhi; 3. AMF; 4. NPK; 5. Rhi + NPK; 6. Rhi + AMF; 7. AMF + NPK; 8. Rhi + AMF + NPK. Plant length, stem diameter and survival in the environment were evaluated. The ANOVA followed by the Duncan test (? = 0,05) was used to compare the means of the treatments. In the four evaluated periods (37, 111, 250 and 360 days), both varieties had a positive effect on height, diameter and survival when applied to NPK treatments. The interaction AMF and Rhizobium sp. favored the growth in diameter of the guapuruvú. For paricá variety that same treatment provided higher growth in height, however, AMF impaired development in diameter of this variety. Thus, it was observed that under low fertility conditions, the interaction AMF + Rhi favored a greater resistance of guapuruvú to abiotic stress compared to treatment 3, and the presence of grasses in the experimental area may have contributed to the reduction on the development of S. parahyba.

Effect of the Organic and NPK Fertilizers on the Growth and Yield of Sweet Potato (Ipomoea batatas (L) Lam) in the Centre of Côte d’Ivoire

In Côte d’Ivoire, the sweet potato is little cultivated but stays however a culture of pension and a food mattering in certain regions. This study was conducted to assess the effect of the application of mineral (NPK 15-15-15, NPK 12-22-22) and organic (poultry manure) fertilizers on yield components of sweet potato (Ipomoea batatas (L) Lam). The experiment was conducted over two years (2016 to 2017) in experimental station of National Center of Agronomic Research (CNRA) of Bouaké in the centre of Côte d'Ivoire. The experiment was conducted following a split plot with 2 factors (variety and fertilizers) and 3 replicates. The main factor was variety with 2 levels (variety Irene and variety TIB-440060) and the subplot was fertilizers application consisted 13 levels (200, 300, 400, 500 kg ha-1 of NPK fertilizers combined 5, 10, 15 t ha-1 of organic fertilizer). Thirteen treatments based on poultry manure (T6, T7), chemical fertilizer NPK 15 15 15 (T1, T3, T4, T5) and NPK 12 22 22 (T8, T10, T11, T12) and their combination (T2 and T9) were tested. The experimental results revealed that that the effects of chemical fertilizer treatments, manure and their combination with mineral fertilizers did not influence the measured parameters. The results also showed that fertilizers improved all the agronomic parameters of sweet potato compared to the control treatment during two years of experiment. However, the Irene variety with a mean weight of 180 g tuberous roots was significantly different from the TIB variety with a mean weight of 138.73 g.
 In the conditions of our study and over the two-year period, producers of sweet potatoes would benefit from using organic fertilizers with the Irene variety.

Linking methane emissions to methanogenic and methanotrophic communities under different fertilization strategies in rice paddies

Rice paddies are a significant source of atmospheric methane (CH4) threatening global warming. Methane fluxes from rice soils are mediated by both methanogens and methanotrophs, while subject to fertilization regimes. A field experiment was conducted to investigate the response of CH4 emissions, with a close link to methanogenic and methanotrophic communities, to different fertilization strategies over two consecutive rice growing seasons in a paddy field. Four fertilized treatments were established consisting of chemical phosphorous (P) and potassium (K) fertilizer (PK), chemical nitrogen (N) PK fertilizer (NPK), chemical NPK combined with organic manure (NPKM), and organic manure alone (M). Results showed that, relative to chemical PK treatment without N fertilizer input, the application of chemical NPK fertilizer, manure, and their combination significantly increased seasonal mean CH4 emissions by 67.4, 20.4 and 101.2%, respectively. Methane fluxes were significantly and positively (r2 = 0.75) related to mcrA gene copy numbers and the ratio of mcrA/pmoA, while negatively (r2 = 0.40) related to pmoA gene copy numbers, which was mainly regulated by the dynamics of water irrigation regime. The abundance of mcrA and pmoA had trade-off relationship over the rice growing season. In comparison with PK fertilization, N fertilized treatments did not alter the seasonal trend of CH4 fluxes, but enhanced the source strength of CH4 emissions through increased mcrA abundances rather than reduced pmoA-dominated methanotrophic CH4 oxidation in rice paddies. In contrast, N fertilization showed no effect on pmoA abundance and associated methanotrophic community in rice paddies. Results highlight that, given the fertilizer-driven balance between methanogenic and methanotrophic communities, fertilization options with either chemical or organic N input stimulated CH4 emissions mainly through improving soil C substrate and methanogenic activities, especially under the combination of chemical and organic N fertilization in rice paddies.

EFFECT OF FERTILIZER (NPK) ON FUNGAL ISOLATES FROM AGRICULTURAL SOILS IN ABUBAKAR TAFAWA BALEWA UNIVERSITY (ATBU), YELWA CAMPUS, BAUCHI.

The effects of NPK on soil fungi was carried out using three(3)soils: two of which soils (maize and Rice farm) were from agricultural soils with history of NPK application, while the third one serve as the control, without the history of NPK application. Isolation and estimation of fungal population was carried out using serial dilution and pour plating technique; soil sample was collected forthnightly, four times (4×) and was serially diluted, cultured using 25oC for 5 days. Macroscopic and microscopic techniques were carried out using the method of described by Barrow and Feltharm. The result revealed that the significant reduction of fungals species, and observed that, Aspergilus niger was present in all soil sample. Aspergillus flavus are present in A, B, but absent in C. It was concluded that NPK and other chemical fertilizer was well tolerated by soil fungal flora Aspergillus niger since there were little variations in their population with respect to each farms. Besides their value in restoring soil nutrient and structure, incorporation of organic fertilizer (NPK) could lead to the control of some soil borne and fungal pathogens. Agricultural activities particularly over-fertilizer application should be controlled as it leads to heavy metals application in the soil which may affects soil microcosm as well as the plants.

Residual effects of neem Azadirachta indica A. Juss. (Sapindales: Meliaceae) seed-based fertilizer and NPK on the performance of Basella alba L. (Caryophyllales: Basellaceae) plant

Organomineral formulations are low input technology fertilizers, which combine the attributes of both organic and inorganic fertilizers. A completely randomized design (CRD) pot experiment was conducted in the screen house of the Department of Crop, Soil and Pest Management, of the Federal University of Technology, Akure, to evaluate the residual effects of neem Azadirachta indica A. Juss. (Sapindales: Meliaceae) seed based fertilizer and NPK 20:10:10 on the growth, yield and nutritional quality of Basella alba L. (Caryophyllales: Basellaceae). Results showed that the plots previously treated with neem seed-based fertilizer especially at 150-300 kg/ha enhanced the growth, yield and nutritional quality of B. alba, and increased these parameter significantly (P < 0.05) compared to the NPK treated and the untreated soil samples. It was therefore concluded that the Neem seed based fertilizer can serve as a viable alternative to NPK chemical fertilizers especially in rotational cropping systems owing to its prolonged soil action.

Impact of Mineral Fertilizers with or without Bio-Fertilizers or Potassium Humate on some Soil Properties, Yield and Quality of Pea Plants Under Salt Affected Soil Conditions

Two field experiments were conducted in clay salt affected soil in Sahl El-Hussinia, El-Sharkia Governorate, Egypt, during two winter seasons2016/2017and2017/2018 to evaluate the effect of mineral fertilizers with different rates(10- 20- 40 kg/fed. N); (15- 25- 30 kg/fed. P2O5,) and (20 -30 – 40 kg/fed. K2O,) alone or with bio-fertilizersor potassium humate on some soil properties (available N, P, K, Fe, Mn, Zn and E.C), yield and quality of pea plants. The results revealed that the studied the soil salinity EC (dSm-1) decreased in soil treated with potassium humate and bio-fertilizers with mineral fertilizers compared with control. The available soil macronutrients i.e. N, P, K, and micronutrients i.e. Fe, Mn and Zn (mg/kg soil) after harvesting in soils treated with biofertilizers and potassium humate with or without mineral fertilizers were increased with increasing mineral fertilizers (NPK) rates. Concerning, the relative increases of all estimated parameters pea plants in both seasons shows gradually increases as follows: potassium humate > bio-fertilizers > mineral fertilizers > control for plant height (cm) , number of branches/ plant, pods/ plants and weight 100 seeds. While, the bio-fertilizers > potassium humate > mineral fertilizers > control for No. of seeds /pods in both seasons. Also, using potassium humate, biofertilizers and mineral fertilizers led to significant increases for dry weight/ plant, fresh pod /plant (g) and yield of pods ton/fed. As well as, potassium humate and biofertilizers in combination with NPK chemical fertilizers increased P and K concentration in seeds. Mineral fertilizers (NPK) combined with or without potassium humate and bio-fertilizers increased on Fe, Mn and Zn concentrations in pea seeds in both seasons .The micronutrients were increased with increasing rate of chemical fertilizers as compared without bio-fertilizers or potassium humate. The interaction between all treatments and mineral fertilizers rates led to significant increase in carbohydrate and proline contents of seeds, while the total sugar content in pea plants was unsignificant. Further, combined application of potassium humate and inorganic fertilizers improved the soil properties. This characterizes the synergistic effect of potassium humate and biofertilizers combined with mineral fertilizers thereby signifying that integrated use of inorganic, organic and biofertilizers helps in upgrading soil health.

Evolution over years of structural characteristics of humic acids in Black Soil as a function of various fertilization treatments

Humic substances are the relatively stable and recalcitrant pool of soil organic carbon in the agricultural system. Humic acid (HA) is an active part of soil humic substances. However, little information exists on how structural characteristics of HA evolved with fertilization years in Black Soil. Soil samples were collected in 1997, 2002, 2008, and 2012 from the Long-term Fertilization Station of Black Soil. The methods of 13C-nuclear magnetic resonance spectroscopy, elemental composition analysis, and infrared spectroscopy were employed to analyze the structure of HA. Long-term fertilization had no significant (P > 0.05) effect on the ratio of O and S to C in HA. The ratio of H to C in HA increased with fertilization years after the application of organic manure (M) single or combined with chemical NPK fertilizers. The ratios of aliphatic C to aromatic C, and alkyl C to O-alkyl C in soil HA increased by 7.72% and 20.3%, respectively, in MNPK and M treatments, whereas NPK treatment declined the ratio of aliphatic C to aromatic C by 2.67% compared with CK treatment. The HA structure tends to become aliphatic and simplified with years of organic manure combined with NPK fertilizers. To save costs, organic manure was only applied once within the period of crop rotation and was combined with NPK every year to satisfy crop demands for soil nutrients.

Nutrient Use Efficiency and Nutrient Uptake Promoting of Rice by Potassium Solubilizing Bacteria (KSB

The current study was carried out in both pot and field conditions to investigate the effects of three KSB strains of Pantoea agglomerans, Rahnella aquatilis and Pseudomonas orientalis on nitrogen (N), phosphorous (P) and potassium (K) uptake, nutrient use efficiency parameters and nutrients remobilization in rice (Oryza sativa L. cv. Pajohesh). The experiments included 15 treatments of KSB inoculations, commercial K biofertilizer and K chemical fertilizer. The results showed that the inoculums of all three KSB strains increased the K, N and P uptake by grain and straw, especially when applied in combination with 1/2 K chemical fertilizer (47.5 Kg/ha) as compared to the control treatment. The highest value of available K in the soil obtained from NPK chemical fertilizer equal to 140.1 and 134.6 mg K per kg of soil in the pot and field experiments, respectively, which were significantly higher than KSB inoculations treatments. Bacterial inoculums coupled with 1/2 K chemical fertilizer also enhanced the nutrient use efficiency (including agronomic efficiency (AE), apparent recovery efficiency (ARE), physiological efficiency (PE), agro-physiological efficiency (APE), internal utilization efficiency (UE), partial factor productivity (PFP), partial nutrient balance (PNB)) and nutrient remobilization. The results indicated that the bioinoculation with these KSB strains isolated from soil paddy could be considered as an effective way to increase potassium, nitrogen and phosphorus uptake by rice plant and enhance their use efficiency and remobilization to grains in the flooding irrigation conditions.

Long-term combined application of manure and chemical fertilizer sustained higher nutrient status and rhizospheric bacterial diversity in reddish paddy soil of Central South China

Bacteria, as the key component of soil ecosystems, participate in nutrient cycling and organic matter decomposition. However, how fertilization regime affects the rhizospheric bacterial community of reddish paddy soil remains unclear. Here, a long-term fertilization experiment initiated in 1982 was employed to explore the impacts of different fertilization regimes on physicochemical properties and bacterial communities of reddish paddy rhizospheric soil in Central South China by sequencing the 16S rRNA gene. The results showed that long-term fertilization improved the soil nutrient status and shaped the distinct rhizospheric bacterial communities. Particularly, chemical NPK fertilizers application significantly declined the richness of the bacterial community by 7.32%, whereas the application of manure alone or combined with chemical NPK fertilizers significantly increased the biodiversity of the bacterial community by 1.45%, 1.87% compared with no fertilization, respectively. Moreover, LEfSe indicated that application of chemical NPK fertilizers significantly enhanced the abundances of Verrucomicrobia and Nitrospiraceae, while manure significantly increased the abundances of Deltaproteobacteria and Myxococcales, but the most abundant Actinobacteria and Planctomycetes were detected in the treatment that combined application of manure and chemical NPK fertilizers. Furthermore, canonical correspondence analysis (CCA) and the Mantel test clarified that exchangeable Mg2+ (E-Mg2+), soil organic carbon (SOC) and alkali-hydrolyzable nitrogen (AN) are the key driving factors for shaping bacterial communities in the rhizosphere. Our results suggested that long-term balanced using of manure and chemical fertilizers not only increased organic material pools and nutrient availability but also enhanced the biodiversity of the rhizospheric bacterial community and the abundance of Actinobacteria, which contribute to the sustainable development of agro-ecosystems.

Distinct responses of ammonia-oxidizing bacteria and archaea to green manure combined with reduced chemical fertilizer in a paddy soil

Ammonia oxidation is the rate-limiting step in nitrification. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are the key drivers of the nitrogen cycle. Chinese milk vetch (MV) has the potential to substitute for part of chemical fertilizer, but it remains unclear how MV is able to replace N fertilizer. The purpose of this study was to investigate the rice yield, soil properties, potential nitrification activity (PNA), abundances, and community structures of ammonia oxidizers in a paddy soil under MV combinations of different rates of chemical fertilizer. This study was conducted at a long-term Experimental Station of the Fujian Academy of Agricultural Sciences, Fuzhou, China. The treatments included a control (without fertilization), NPK (chemical fertilizer), MF80 (MV plus 80% NPK), MF60 (MV plus 60% NPK), and MF40 (MV plus 40% NPK). Soil samples were collected after the rice harvest. We determined the soil physico-chemical properties and PNA. The abundances and community structures of AOB and AOA were assessed using their ammonia monooxygenase (amoA) genes. Quantitative PCR was used to determine the gene abundance, and Illumina Miseq sequencing was used to explore the diversity of AOB and AOA. MV significantly increased the soil organic matter and PNA in comparison to the NPK. The available nitrogen content was higher in the MV treatments than in the control and NPK. Compared to the NPK, the application of MV increased the AOB abundance but decreased that of AOA. The abundance of AOA was higher in the control and NPK, but lower in the MV treatments than that of AOB. PNA was significantly positively correlated with the AOB abundance. The primary dominant OTU of the AOB group was Nitrosospira. MV significantly affected the AOB community, while no impact on the AOA community was observed. Principal coordinate analysis showed that the MV treatments were significantly distinct from those of the control and NPK. Redundancy analysis indicated that the soil OM, TN, AN, pH, and PNA were significantly correlated to the AOB community structure. This study demonstrated that MV combined with reduced chemical fertilizer would contribute to the improvement of soil fertility and PNA, resulting in rice yield comparable to that of the NPK. MV had a stronger effect on the AOB community than did chemical fertilizer. AOB played a more important role than AOA in the ammonia oxidation in this soil.

Improved Productivity of Superior Seedless Grapevines Using Irradiated Compost and Bio-Fertilization in the Desert Land

The application of some biofertilizers and irradiated compost for replacement of NPK chemical fertilizers was studied on five year-old superior seedless grapevine to determine the best dosage that would improve growth, yield and berry characteristics and reduce the rates of mineral fertilizations of NPK without any negative effect. The experiment was conducted in a vineyard located at Cairo-Alexandria Desert Road in 2015 and 2016 seasons, and consist of six treatments, 100% NPK (control), 100% NPK + microbein, 50% NPK + 50% irradiated compost (IC), 50% NPK + 50% irradiated compost + microbein, 100% irradiated compost and 100% irradiated compost + microbein. All treatments were very effective in stimulating growth characters as well as physical and chemical characteristics of the berries in relation to the control treatment. Petiole NPK %, leaf chlorophyll content and cane carbohydrate content were increased more than the control. In addition, cluster weight was significantly increased as a result yield per vine was increased. The highest superior effect was recorded in response to 100% IC + microbein application. This improvement could be attributed to positive influence upon the biosynthesis of the primary metabolites (soluble carbohydrates, chlorophyll and carotenoid pigments) and secondary metabolites (proteins, polyphenols, auxins). In addition, both compost especially when irradiated and biofertilizers increase the availability and uptake of N, P and K, which was reflected on growth parameters. Finally, irradiated compost alone or combined with microbein could be used as a valid alternative method to the expensive hazardous mineral fertilizers.

Comparative study of Azotobacter with or without other fertilizers on growth and yield of wheat in Western hills of Nepal

A pot experiment was conducted to evaluate the effects of Azotobacter inoculant on the growth and yield of wheat (variety Gautam) at the premise of Lamjung Krishi Campus, Nepal during the winter season of 2016–17. A completely randomized design was chosen with seven treatments (T1, T2, T3, T4, T5, T6, and T7) each replicated three times. The treatments were control (T1), 120:80:80 kg NPK ha−1 (T2), Azotobacter seed inoculated (T3), Azotobacter soil application (T4), Azotobacter + 120:80:80 kg NPK ha−1 (T5), Azotobacter + 10 t FYM ha−1 (T6), Azotobacter + 120:80:80 kg NPK ha−1 + 10 t FYM ha−1 (T7). Root length, root weight, shoot weight, plant height, panicle weight, grain weight, grain yield, total biomass, and biological yield were significantly affected by treatments. Inoculation of Azotobacter only increased 16.5%–19.42% grain yield over control i.e. non inoculated treatments while with other fertilizers increase was of range 19.42%–63.1%. The increase in yield was 23.3% with only chemical fertilizer NPK (T2) over control. So Azotobacter can be used as a biofertilizer for greater yield and the yield is highest with Azotobacter combined with farmyard manure and inorganic fertilizer (NPK).

Soil moisture variation under different water and fertilization managements in apple orchard of Weibei dryland, China

To evaluate the variations of soil moisture under different water and fertilizer treatments in apple orchard in the Weibei dryland, a field experiment was carried out in 2013-2016 at Tianjiawa Village, Baishui County, Shaanxi Province. There were three treatments, i.e., farmers traditional model (only addition of NPK chemical fertilizer, FM), extension model (swine manure and NPK chemical fertilizer combined with black plastic film in tree row space, EM), and optimized model (swine manure and NPK chemical fertilizer combined with black plastic film in tree row space and planting rape in the inter-row of apple trees, OM). The results showed that OM treatment significantly increased soil water storage capacity in 0-200 cm soil layer. Water content of 0-100 cm soil layer was increased by 5.6% and 15.3% in the dry season compared with FM and EM treatment, respectively. Moreover, the soil water relative deficit index of OM was lower than that of EM in 200-300 cm soil layer. The rainfall infiltration in the dry year could reach 300 cm depth under OM. Meanwhile, OM stabilized soil water content and efficiently alleviated the desiccation in deep soil layer. Compared with FM and EM, the 4-year average yield of OM was increased by 36.6% and 22.5%, respectively. In summary, OM could increase water use efficiency through increasing the contents of available soil water and improving the soil water condition in shallow and deep layers, which help alleviate the soil deficit in deep layer and increase yield.

농경지 아산화질소 배출계수의 연간 변동 특성 분석

We aimed at investigating the difference in N₂O emission factors of chemical and organic fertilizers and identifying the main factors influencing annual fluctuations in N₂O emission. We conducted two-year experiments in 2016 and 2017 in an agricultural field planted with sweet potato (Ipomoea batatas). Treatments included chemical NPK fertilizer (NPK) and chicken compost application at 10 ton ㏊SUP-1/SUP, 20 ton ㏊SUP-1/SUP, and 30 ton ㏊SUP-1/SUP rates (CK1, CK2 and CK3). Control was also employed with no addition. Results showed that N₂O emission rates were significantly related with soil water status and soil available N contents. Significant correlation between % water filled pore space (WFPS) and N₂O emission was observed only when the %WFPS was greater than 40% and during the initial stage of the experiment (＜60 d). Comparison of the emission factors in 2016 and 2017 showed us that the emission factor was greater in 2016 when the %WFPS was maintained higher by 16.5% compared to that in 2017. In 2016, the emission factor of organic fertilizer was higher than that of chemical fertilizer, while in 2017, the pattern was reversed. Annual variability in N₂O emission could also be originated from the available N contents remaining in soil after being taken up by plants. If we apply excessive N fertilizer, the soil would contain excess amount of N which was not uptaken by plants, leading to a huge increase in N₂O emission. This case would overestimate emission factor, which was the case for the organic fertilizer in 2016. Over-fertilization should be avoided when we set up an experiment to determine N₂O emission factor.