Combined Application Of Chemical Fertilizers Research Articles

A study on the changes in rice composition under reduced fertilization conditions using Raman spectroscopy technology.

The substitution of microbial fertilizer for chemical fertilizer can not only improve soil fertility but also effectively enhance rice quality. To investigate the effect of different amounts of combined application of chemical fertilizer and microbial fertilizer on the amylose content of rice, this study adopts theoretical calculations to compare the preprocessed Raman spectroscopy information of rice with reduced fertilization and establishes a recognition model for the amylose content of rice, which is used to detect the amylose content in rice. Based on the amylose spectral values measured by Raman spectroscopy and the known starch structure and functional groups, the Raman peaks are mainly distributed in the range of 400cm- 1 to 1400cm- 1. The Raman characteristic peaks at 483cm- 1, 869cm- 1, 933cm- 1, 1082cm- 1, 1126cm- 1, 1335cm- 1, 1385cm- 1, and 1455cm- 1 exhibit strong vibration modes, which are consistent with its main nutrient component of amylose. By comparing the measured amylose content in the regions treated with microbial fertilizer combined with different amounts of reduced fertilization and the spectral intensity values of amylose measured by Raman spectroscopy, the results show that the treatment of combining conventional amounts of microbial fertilizer with different amounts of reduced chemical fertilizer exhibits a decreasing trend in the amylose content of rice.

Lowering Chemical Fertilizers Rate in ‘Black Amber’ Plum Orchard for Improving Sustainable Resource Management: Effect on Soil Health and Fruit Quality

ABSTRACT The combined application of chemical fertilizers and organic material is a transitional approach toward more sustainable and productive farming. This study aimed to investigate the response of low chemical fertilizer rates and supplementing with organic materials on soil health and fruit quality. In plum orchard, combination of reduced chemical fertilizer rates (R80; R70; R60) with organic manures (F; V) at varying levels based the loss in nitrogen requirement and microbial inoculants (Bf; J) were studied over the conventional approach (R100) on soil health and fruit quality in a 2-year experiment. Soil analysis showed soil physico-chemical properties and enzymes activity with application of R70+V10+Bf. Compared to integrated treatments R100 saw highest availability of soil potassium and calcium. Application of R70+V10+J resulted in maximum improvement in fruit weight, TSS and soluble sugar content. Fruit set percentage was higher in treatment R70+V10+Bf. Fruit yield showed significant changes with treatments R70+V10+Bf and R70+V10+J having similar yield to R100. Our results suggest that by reducing the amount of chemical fertilizer by 30% and partially replacing it with organic materials had a positive effect on soil health without affecting the fruit production and quality.

Manure application maintained the CO2 fixation activity of soil autotrophic bacteria but changed its ecological characteristics in an entisol of China

The response of soil autotrophs to anthropogenic activities has attracted increasing attention against the background of global change. Here, three entisol plots under different fertilizing regimes, including no fertilization (CK), manure (M), and a combined application of chemical fertilizer and manure (NPKM) were selected, and then the soil RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) activity and cbbl (gene encoding the large subunit of RubisCO) composition were measured to indicate the activity and community of autotrophic bacteria, respectively. The results revealed that the RubisCO activity of CK showed no difference from that of M but was significantly higher than that of NPKM. The CK and M had the lowest and highest soil cbbl abundance, respectively. The α-diversity of soil cbbl-carrying bacteria showed no significant difference among these treatments, whereas they showed significantly different community structures of cbbl-carrying bacteria. Meanwhile, compared with CK, M had significantly lower abundances of bacterial species with the functions of nitrogen fixation (Azoarcus sp.KH32C) or detoxification (Methylibium petroleiphilum), indicating that manure application might have an inhibiting potential to some beneficial autotrophic bacterial species in this entisol.

Correction to: The effects of combined application of chemical fertilizer, functional bacteria and plant hormones on vegetation restoration of desertification land in Zoige Plateau

Correction to: The effects of combined application of chemical fertilizer, functional bacteria and plant hormones on vegetation restoration of desertification land in Zoige Plateau

Yield and Antioxidant Quality of Habanero Chili Pepper by Supplementing Potassium with Organic Products

Habanero chili pepper has great economic importance in Mexico, but its production is limited due to different factors that affect quality. Given the high demand and prices of the fruit, the production of this crop is spreading to other regions in search of new production systems. The aim of this research work was to assess the yield and antioxidant components of the fruit by supplementing potassium from organic sources. The “Campeche”, “Palenque”, and “Jaguar” varieties were studied in five NPK treatments; replacing the % of potassium with humus and compost: (T1) 240-200-120+50% of K from liquid earthworm humus; (T2) 240-200-180+25% of K from liquid earthworm humus; (T3) 240-200-120+50% of K from vermicompost; (T4) 240-200-180+25% of K from vermicompost; and (T5) 240-200-240 (control, 100% chemical nutrition). For yield components, there were significant differences, highlighting the importance of the nutrition source for the yield and weight of fruits per plant. The control (T5) presented a value of 39 t·ha−1 and was similar to treatments T2 and T3 with a supplement of 25 and 50% organic K. For the polar and equatorial diameter of fruit, as well as for plant height and leaf area, treatments supplemented with 50% organic K (T1 and T3) were more effective. For the varieties evaluated, no differences in yield and fruit weight were found; however, Campeche produced more fruits per plant with a greater equatorial diameter, while Palenque obtained fruits with a greater polar diameter and taller plants. The results of antioxidant compounds show that organic K supplementation improves the quality of total carotenoids, β-carotenes, and xanthophylls compared to 100% chemical fertilization, since total carotenoid content is improved by 54.2%, β-carotenes by 46.4%, and xanthophylls by 37.8%, respectively. The Campeche variety was the one that presented the best fruits with the highest antioxidant quality. These results indicate a positive effect of the combined application of chemical fertilizer with worm humus on yield and its components in pepper and other crops and show an economic, ecological, and sustainable alternative to the production of habanero chili pepper.

The effects of combined application of chemical fertilizer, functional bacteria and plant hormones on vegetation restoration of desertification land in Zoige Plateau

The effects of combined application of chemical fertilizer, functional bacteria and plant hormones on vegetation restoration of desertification land in Zoige Plateau

Effects of biochar coupled with chemical and organic fertilizer application on physicochemical properties and in vitro digestibility of common buckwheat (Fagopyrum esculentum Moench) starch

Common buckwheat starch, a functional ingredient, has wide food and non-food applications. Excessive chemical fertilizer application during grain cultivation decreases quality. This study examined the effects of different combinations of chemical fertilizer, organic fertilizer, and biochar treatment on the physicochemical properties and in vitro digestibility of starch. The amendment of both organic fertilizer and biochar was observed to have a greater impact on the physicochemical properties and in vitro digestibility of common buckwheat starch in comparison to organic fertilizer amendment solely. The combined application of biochar, chemical, and organic nitrogen in an 80:10:10 ratio significantly increased the amylose content, light transmittance, solubility, resistant starch content, and swelling power of the starch. Simultaneously, the application reduced the proportion of amylopectin short chains. Additionally, this combination decreased the size of starch granules, weight-average molecular weight, polydispersity index, relative crystallinity, pasting temperature, and gelatinization enthalpy of the starch compared to the utilization of chemical fertilizer alone. The correlation between physicochemical properties and in vitro digestibility was analyzed. Four principal components were obtained, which accounted for 81.18 % of the total variance. These findings indicated that the combined application of chemical fertilizer, organic fertilizer, and biochar would improve common buckwheat grain quality.

Effects of Combined Application of Chemical Fertilizer and Biochar on Soil Physio-Biochemical Properties and Maize Yield

Excessive, long-term chemical fertilizer application adversely affects soil quality and maize yield. The combined application of biochar with chemical fertilizer can increase maize yield and improve soil fertility. A four-year field experiment was conducted to determine soil physio-biochemical properties and maize yield under a soybean–maize rotation in the black soils of Northeast China. There were five treatments, including no fertilization (CK), fertilizer (NPK), fertilizer + biochar (15.75 t·hm−2, BC1), fertilizer + biochar (31.50 t·hm−2, BC2), and fertilizer + biochar (47.25 t·hm−2, BC3). Compared with CK, the number of macroaggregates and the average weight diameter of soil aggregates in BC2 treatment increased significantly by 10.3% and 24.5%, respectively. The soil pH in the study area was 7.03, and it increased in all treatments except for BC1. The highest pH of 7.17 was recorded in NPK and BC2 treatments, which was around the optimal soil pH. In contrast to the CK and NPK treatments, the biochar application increased soil organic carbon (SOC) and total nitrogen (TN) content. The BC2 treatment improved soil C/N and increased the copy number of soil bacteria by 25.6% compared to CK. The combined application of chemical fertilizer and biochar was better than NPK treatment alone, and improved soil mechanical composition and fine soil particle contents (powder and clay). Mixed biochar with chemical fertilizer application also significantly increased maize yield and the weight of 100 grains increased from 9.5% to 10.9% compared to CK. The maize yield of the three fertilizer and biochar treatments was higher than treatments with applied chemical fertilizer alone, in the order of BC2 > BC3 > BC1 > NPK > CK (BC2 treatment increased by 34.8%). Additionally, the maize yield was significantly and positively correlated with soil aggregates, organic carbon and total nitrogen (p < 0.05) as well as the 100-grain weight (p < 0.01). The application of 31.50 t·hm−2 (BC2 treatment) of biochar can enhance soil physicochemical properties and improve maize yield.

Responses of soil microbial biomass nitrogen to organic fertilizer with different degrees of maturity and regu-lation to soil mineral nitrogen.

By combining the composting process with soil culture experiment, we conducted an experiment with four treatments, including conventional chemical fertilizer (CK), chemical fertilizer + compost maturity reaching 50% germination index (GI, the same below) organic fertilizer (CO1), chemical fertilizer + compost maturity reaching 80% GI organic fertilizer (CO2), chemical fertilizer + compost maturity reaching 100% GI organic ferti-lizer (CO3). We measured soil microbial biomass nitrogen (MBN), mineral nitrogen (NH4+-N, NO3--N), net nitrification rate, microbial biomass carbon (MBC), dissolved organic carbon (DOC), soil urease and soil protease, aiming to reveal the regulatory effect of soil MBN on mineral nitrogen. The results showed that organic fertilizer application significantly increased MBN and NH4+-N concentrations by 50.1%-62.4% and 109.9%-147.1%, reduced NO3--N concentration and net nitrification rate by 23.3%-46.8%, and 26.2%-51.5%, and enhanced MBC, DOC, urease and protease activities by 33.8%-69.6%, 7.4%-20.8%, 11.2%-69.0% and 9.4%-25.1%, respectively. The change ranges of CO2 and CO3 were significantly higher than CO1. Redundancy analysis (RDA) and structural equation model (SEM) results showed that the application of organic fertilizer with higher degree of maturity (GI≥80%) positively regulated soil MBC, MBN, NH4+-N, and the activities of urease and protease, but had a negative effect on soil net nitrification rate. The combined application of chemical fertilizers and high decomposed organic fertilizers could significantly increase soil MBN and NH4+-N contents, as well as soil urease and protease activities, but reduce soil net nitrification rate. To efficiently utilize organic solid wastes, it is recommended to use chemical fertilizer in combination of organic fertilizers with 80% decomposing degree in practical production to reduce the cost in both economy and time.

Combined application of chemical fertilizers, organics and foliar spray of zinc and iron on yield, quality and water productivity of aerobically grown rice (Oryza sativa) in calcareous soil

Increasing multi-nutrient deficiencies and water scarcity is a major challenge for rice cultivation. In calcareous soils, nitrogen (N), iron (Fe) and zinc (Zn) deficiencies are major constraints for aerobically grown rice. Thus, a field study was conducted in factorial randomized block design with 18 treatment combinations viz. 75% recommended dose of nitrogen (RDN) through chemical nutrient source and 25% RDN through of organic sources (vermicompost or poultry manure or farm yard manure) and foliar spray with Zn and Fe at tillering and panicle initiation stage. All the growth related traits, yield attributes, yield and nutrient uptake were significantly influenced by nutrient management practices. On an average, mean grain yield was improved by 28.5% with the application of 100% RDN through chemical fertilizers + 25% RDN through vermicompost over alone 100% RDN through chemical fertilizer. Higher nitrogen uptake (100.4 kg ha−1), phosphorous (14.7 kg ha−1), potassium (95.9 kg ha−1), iron (1085.1 g ha−1) and zinc (295.1 g ha−1) were also recorded with same treatment. Application of 75% RDN through chemical fertilizer + 25% RDN through poultry manure recorded significantly higher water productivity of 0.130 US$/m3 than all other treatments while application with 100% RDN through chemical fertilizers recorded lowest water productivity of 0.091 US$/m3. The present finding indicates that under current situation of declining water resources and increasing multi-nutrient deficiencies, combined application of chemical fertilizers and poultry manure along with foliar spray of Zn and Fe will enhance the quality produce, and water productivity in aerobically grown rice in calcareous soils.

Combined application of chemical fertilizer with green manure increased the stabilization of organic carbon in the organo-mineral complexes of paddy soil.

The influence of the combined application of chemical fertilizer with green manure on the stabilization of organic carbon (C) was explored in the organo-mineral complexes of paddy soil. The organo-mineral complexes were isolated from paddy soil treated with no fertilizer, chemical fertilizer alone, and chemical fertilizer combined with increasing amounts of Chinese milk vetch (CMV). The stability (reflected by mineralizable carbon proportion), the content and chemical composition of organic C, the Fe/Al oxides and their associated organic C in the organo-mineral complexes were investigated. The application of chemical fertilizer in combination with CMV significantly improved the stability of organic C in the organo-mineral complexes. The combined application of chemical fertilizer with CMV slightly decreased the proportion of O-alkyl C (easily decomposed) yet somewhat increased the proportions of carbonyl C and aromatic C (difficultly decomposed) and aromaticity index in the organo-mineral complexes. The treatments of chemical fertilizer combined with CMV showed more Fe oxides and Fe/Al-associated organic C and higher proportion of Fe/Al-associated organic C in the total organic C of the organo-mineral complexes. The mineralizable carbon proportion displayed significantly negative correlations with carbonyl C and Fe/Al oxide-associated organic C in the organo-mineral complexes. The Fe/Al oxides were likely to be preferentially bound with the aromatic C and carbonyl C in the organo-mineral complexes. Overall, the combined application of chemical fertilizer with CMV facilitated the association of difficultly decomposed carbon and Fe/Al oxides, which significantly improved the stabilization of organic C in the organo-mineral complexes ofpaddy soil.

Effect of Integrated Use of Farmyard Manure and Chemical Fertilizers on Soil Properties and Productivity of Rice in Chitwan

The effect of sole application of farm yard manure (FYM) and combined application of chemical fertilizers and FYM on soil properties and growth and yield traits of rice (Variety: Ramdhan) was studied on sandy loam soil at Rambagh, Chitwan, Nepal from June to November 2019. The seven treatments were studied in a randomized complete block design with four replications: T1: 100% recommended dose of inorganic fertilizer (RDIF) (i.e., 100:60:40 NPK kg ha-1); T2: 50% RDIF+ FYM @ 9.9 Mt ha-1; T3: 50% RDIF+ FYM @ 31.3 Mt ha-1; T4: 50% RDIF+ FYM @ 11.05 Mt ha-1; T5: FYM @ 19.83 Mt ha-1. The results indicated that combined application of chemical fertilizers and farmyard manure was found to have a significant effect on the number of effective tillers per m-2 and grain yield of rice. There was no significant interaction between thousand grain weight and sterility percent. The highest grain yield of 3,453.69 kg ha-1 and the highest number of effective tillers per m-2 (299) were found in the application of 50% RDIF+ FYM @ 31.3 Mt ha-1. The application of the highest level of FYM alone improved the soil properties. The highest values of available soil organic carbon (34.67 Mt ha-1), available soil nitrogen (1.24 Mt ha-1), and available soil phosphorus (39.57 kg ha-1) at a depth of 0–15 cm were found with the application of FYM @ 62.5 Mt ha-1. The findings of this study suggest that farmers can apply FYM @ 62.5 Mt ha-1 to improve soil properties and 50% RDIF + FYM @ 31.3 Mt ha-1 to have the higher grain yield of rice.

Organic and Inorganic Amendments Shape Bacterial Indicator Communities That Can, In Turn, Promote Rice Yield.

The dynamic patterns of the belowground microbial communities and their corresponding metabolic functions, when exposed to various environmental disturbances, are important for the understanding and development of sustainable agricultural systems. In this study, a two-year field experiment with soils subjected to: chemical fertilization (F), mushroom residues (MR), combined application of chemical fertilizers and mushroom residues (MRF), and no-fertilization (CK) was conducted to evaluate the effect of fertilization on the soil bacterial taxonomic and functional compositions as well as on the rice yield. The highest rice yield was obtained under MRF. Soil microbial properties (microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), urease, invertase, acid phosphatase, and soil dehydrogenase activities) reflected the rice yield better than soil chemical characteristics (soil organic matter (SOM), total N (TN), total K (TK), available P (AP), available K (AK), and pH). Although the dominant bacterial phyla were not significantly different among fertilizations, 10 bacterial indicator taxa that mainly belonged to Actinobacteria (Nocardioides, Marmoricola, Tetrasphaera, and unclassified Intrasporangiaceae) with functions of xenobiotic biodegradation and metabolism and amino acid and nucleotide metabolism were found to strongly respond to MRF. Random Forest (RF) modeling further revealed that these 10 bacterial indicator taxa act as drivers for soil dehydrogenase, acid phosphatase, pH, TK, and C/N cycling, which directly and/or indirectly determine the rice yield. Our study demonstrated the explicit links between bacterial indicator communities, community function, soil nutrient cycling, and crop yield under organic and inorganic amendments, and highlighted the advantages of the combined chemical and organic fertilization in agroecosystems.

Effect of Combined Application of Biochar with Chemical Fertilizer and Organic Fertilizer on Soil Phosphatase Activity and Microbial Community

To study changes in phosphatase activity, we examined the diversity of phoC and phoD gene microbial communities in the rhizosphere and non-rhizosphere soil of plants under the treatment of chemical fertilizer and organic fertilizer combined with biochar. These results can provide a certain theoretical guidance for the conversion of insoluble phosphorus in the soil phosphorus pool to the inorganic phosphate ion that can be absorbed by plant roots and also provide a certain experimental basis for the improvement of the availability of phosphorus in the soil and the agricultural utilization of biochar. In this study, corn stalks and rice husk stalks were used as test materials, and the pot experimental method was adopted using the following treatments:set control (CK), traditional fertilization (F), chemical fertilizer+20 t·hm-2 rice husk biochar (FP), chemical fertilizer+10 t·hm-2rice husk biochar+10 t·hm-2 corn biochar (FPM), organic fertilizer+20 t·hm-2 rice husk biochar (PP), and fresh organic fertilizer+20 t·hm-2 rice husk biochar (NPP). We determined the rhizosphere and non-rhizosphere soil acid phosphatase (ACP) activity and alkaline phosphatase (ALP) activity and used T-RFLP technology to analyze the diversity of phoC and phoD genes in order to clarify the impact of biochar on the micro-ecosystem formed by the plants, soil, and microorganisms. The results showed that:① the ALP and ACP activities of each treatment in the non-rhizosphere soil were lower than that of CK. In the rhizosphere soil, the ALP activity was significantly increased after the combined application of chemical fertilizer and organic fertilizer with biochar, and the ACP activity in the rhizosphere soil was higher than that in the non-rhizosphere soil. ② The combined application of biochar with chemical fertilizers and organic fertilizers significantly increased the diversity of phoC and phoD genes communities in rhizosphere and non-rhizosphere soils (P<0.05); the diversity and richness of microbial communities in rhizosphere soil were higher than that in non-rhizosphere soils. ③ ACP activity was negatively correlated with phoC gene microbial community, and most ALP activity was positively correlated with phoD microbial community.

Replacing 30 % chemical fertilizer with organic fertilizer increases the fertilizer efficiency, yield and quality of cabbage in intensive open-field production

ABSTRACT: The combined application of chemical fertilizer and organic fertilizer is an effective way to improve soil fertility, crop yield and quality. In this study, a field experiment was conducted to evaluate the yield, quality and fertilizer use efficiency of cabbage (Brassica oleracea var. capitata L.) grown under different ratios of organic fertilizer replacing chemical fertilizer at a rate of 225 kg N ha-l in 2019 and 2020. The fertilizer treatments included N0 (non nitrogen fertilizer), CK (only compound fertilizer was applied, N:P:K=15.0 %:6.5 %:12.4 %), T1, T2 and T3 (organic fertilizer replaced 15 %, 30 % and 45 % chemical fertilizer, respectively), and T4 (total nutrient input was reduced by 10 % under T2). Results showed that T2 had the highest marketable yield and fertilizer use efficiency, as well as the best quality. The marketable yield, vitamin C content, soluble sugar content, REN (apparent uptake efficiency of fertilizer N) and AEN (agronomic N use efficiency) of T2 increased by 32.2 %, 14,9 %, 5.5 %, 97. % and 55.6 %, respectively, in contrast, the crude fibers decreased by 34.0 %, compared with CK in the two years. In addition, T4 guaranteed the yield and moderately improved the quality of cabbage, compared with CK. Therefore, we can alternatively apply fertilization according to the purpose of capturing the highest yield or properly declining fertilizer to sustain soil texture and productivity.

Long-term combined application of chemical fertilizers and organic manure shapes the gut microbial diversity and functional community structures of earthworms

Earthworms are crucial regulators of many soil ecosystem processes; however, the effects of fertilization regimes on earthworm gut microbiota remains poorly understood. Here, we investigated the effects of 10 years of fertilization on the gut microbiota of two different earthworm species, Metaphire californica and Amynthas phaselus, belonging to anecic and endogeic ecological groups, respectively. Five fertilization treatments were designed as follows: non-nitrogen fertilizer (CK), nitrogen fertilizer only (NPK), and the combined application of inorganic fertilizers and three different application rates of pig manure (NPKM1, NPKM2, NPKM3). We observed that, compared with the CK and NPK treatments, the organic manure treatments had strong effects on both earthworm gut microbial communities and the associated metabolic functions. The lower application rate of organic manure significantly increased the gut microbial diversity of both earthworm species, which may have further improved their gut microbial metabolic potential, especially for the metabolism of various carbon resources. With the increasing application of organic fertilizers, the abundance of several bacterial families, such as Comamonadaceae, Oxalobacteraceae, and Cytophagaceae, significantly increased in the gut of M. californica. These families have also been identified as the primary indicator taxa of high organic matter inputs and play a crucial role in regulating microbial community functionalities. However, a similar trend was not observed in the gut of A. phaselus, indicating that A. phaselus might be less sensitive to fertilization regimes because it lives deeper in the soil and has a long digestive tract compared with those of M. californica. Our results demonstrated that long-term organic amendment application significantly shapes earthworm gut microbial communities and results in greater decomposition potential of the earthworm gut. Furthermore, our study found that lower application rates of organic matter may be beneficial for earthworm gut microbial diversity and functional structures.

Integrated nutrient management in underground vegetable crops

Vegetable comprises large number of plants, consumed as leaf, fruits, flowers, stem, roots etc. They are rich in nutrients like carbohydrates, proteins, fats, minerals and vitamins. They are mostly cultivated around the year throughout the country. India is the second largest producer of vegetables next to China in the world. It is cultivated in an area of 9575 (‘000’ ha) with production of 166608 (‘000’ MT) with the productivity of 17.40 MT/ha (NHB, 2016). Now a days, modern agriculture depend heavily on use of chemical fertilizers for boosting crop yield. However, indiscriminate use of fertilizers has an adverse effect on long term soil health and environment which has global attention. The realistic solution is Integrated Nutrient Management system are the combined application of chemical fertilizers, along with organic manure, green manure, bio-fertilizer and other organic recyclable materials for crop production.

Changes in Nitrogen Pools in the Maize–Soil System after Urea or Straw Application to a Typical Intensive Agricultural Soil: A 15N Tracer Study

A maize pot experiment was conducted to compare the difference of N distribution between bulk and rhizospheric soil after chemical fertilizer with or without soil straw amendment at an equivalent N rate using a 15N cross-labeling technique. Soil N pools, maize N and their 15N abundances were determined during maize growth. The urea plus straw treatment significantly (p &lt; 0.05) increased the recovery of urea N in soil and 26.0% of straw N was assimilated by maize. Compared with urea treatment in bulk soil, urea plus straw treatment significantly (p &lt; 0.05) increased the concentration and percentage of applied N as dissolved organic N (DON) and microbial biomass N (MBN) from milk stage to maturity, increased those as particulate organic N (PON) and mineral associated total N (MTN) throughout maize growth and decreased those as inorganic N (Inorg-N) from the eighth leaf to the silking stage. Compared with bulk soil, rhizospheric soil significantly (p &lt; 0.05) decreased the concentration and percentage of applied N as PON and increased those as Inorg-N and MTN in both applied N treatments from the silking stage, and significantly (p &lt; 0.05) decreased the concentration and percentage of applied N as microbial biomass N (MBN) in the urea plus straw treatment. Overall, straw N was an important N source and combined application of chemical fertilizer with straw increased soil fertility, with the rhizosphere regulating the transformation and supply of different N sources in the soil–crop system.

English

The impact of organic fertilizers on the carbon source/sink balance of tobacco soil ecosystem remains controversial. A two-year field experiment was conducted to investigate the effects of different fertilization treatments(no fertilizer,chemical fertilizer, chemical fertilizer and organic fertilizer) on greenhouse gas (GHG) emissionsincludingsoil carbon dioxide (CO2), nitrous oxide (N2O), ammonia volatilization and comprehensive greenhouse effects. The results showed that tobacco soil ecosystem can be carbon source orsink, depending mainly on the carbon sequestration of the plant. Comparing with chemical fertilizer, the combined application of chemical fertilizer and organic fertilizer increased the CO2emission flux and C emission from soil, and significantly increased the carbon sequestration of tobacco plants. The carbon sequestration function of organic fertilizer was closely related to the carbon accumulation of tobacco plants. Comparedwith the chemical fertilizer, soil ammonia volatilization and N2O emission flux were increased by adding organic fertilizer. Both the soil N emission and the biological nitrogen fixation were increased by organic fertilizer. The greenhouse gas emission intensity(GHGI)of organic fertilizer treatment decreased by 14.60%, a remarkable emission reduction, whilethe tobacco yield of organic fertilizer treatment increased 19.12%. Therefore, increasing organic fertilizer in tobacco planting fields is an important way to promote tobacco yield, carbon sequestration and emission reduction.© 2021 Friends Science Publishers

Effects of Sheep Manure Combined with Chemical Fertilizers on Maize Yield and Quality and Spatial and Temporal Distribution of Soil Inorganic Nitrogen

In order to explore the influences of sheep manure mixed with chemical fertilizers upon the yield and quality of maize and the spatial and temporal distribution of soil inorganic nitrogen under the wheat‐maize rotation system, achieve increased yield and efficiency with rational fertilization of maize in this area, and at the same time provide a reasonable scientific basis for green production, an experiment was performed at Wanbei Comprehensive Experimental Station of Anhui Agricultural University in 2020 accordingly. The soil for the experiment is sand ginger black soil, and the subject is Zhengdan 958. The experiment adopts a randomized block design with 6 treatments: no fertilizer (T1), single application of the chemical fertilizer (T2), 15% sheep manure mixed with the chemical fertilizer (T3), 30% sheep manure combined with the chemical fertilizer (T4), 45% sheep manure added with the chemical fertilizer (T5), and only sheep manure (T6). The amount of nitrogen, phosphorus, and potassium applied in each treatment remains the same. The result of the experiment shows that T1 treatment has the lowest yield, followed by T6 treatment. The yield of sheep manure combined with the chemical fertilizer is much higher than that of pure sheep manure and no fertilizer. Among them, the yield of T3 is the highest and T4 is the lowest. There is no obvious variation between the combined treatments. Compared with single usage of the chemical fertilizer, the fat content of maize kernels treated with T3 and T4 is 8.9% and 5.6% higher than that of T2 treatment. The protein content of maize kernels treated with T3, T4, and T5 is 2.3%, 2.5%, and 2% higher than that of T2. It shows that the mixture of sheep manure and chemical fertilizer can improve the quality of maize kernels in some degree. The partial productivity of the nitrogen fertilizer in T3 and T5 treatments is 3.7% and 0.8% higher than that of T2 treatment, and the agronomic utilization rate of the nitrogen fertilizer is 10.9% and 1.6% higher than that of T2 treatment. T6 is much lower than that of T2 treatment. It certifies that the combined application of chemical fertilizers with sheep manure can increase the partial productivity and the agronomic utilization rate of the nitrogen fertilizer and increase crop yields and farmers’ income. The nitrate nitrogen of 40–60 cm soil layer is increased by 30.4%, 60–80 cm soil layer is increased by 56.5%, and 80–100 cm soil layer is increased by 11.6%. It shows that the mixed usage of organic and inorganic fertilizers can prevent nitrate nitrogen from moving to deep soil and reduce groundwater pollution.