Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potentia...Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.展开更多
A field experiment was conducted in the Western Highlands of Cameroon to study the effects of Calliandra calothyrsus, sterilized compost, non-sterilized compost and mineral fertilizers （NPK 11：11：22） on physical c...A field experiment was conducted in the Western Highlands of Cameroon to study the effects of Calliandra calothyrsus, sterilized compost, non-sterilized compost and mineral fertilizers （NPK 11：11：22） on physical characteristics, yield components and late blight disease severity of potato （Solanum tuberosum）. A two factorial treatment combination made up of fertilization schemes and sanitary measures were laid out in a randomized complete block design （RCBD） with four replicates and 10 treatments. Data collected were subjected to a multivariate ANOVA and means separated with the Dunnett t-test with Calliandra calothyrsus considered as the main treatment. Mineral fertilizers and Calliandra calothyrsus significantly augmented stem diameter, plant height and plant vigor, total and marketable yields, despite the fact that late blight severity was high in the two treatments. The correlation matrix showed that total yield had significant and positive correlation with stem diameter （r = 0.74）, plant height （r = 0.61）, plant vigor （r = 0.61） and marketable yield （r = 0.99） and negative correlation （r = -37） with late blight severity. The increase observed is attributed to the nutrient contents of the treatments applied. Leafy prunings of C. calothyrsus increase soil organic matter which probably improves moisture retention and biological activity. The highest late blight severity recorded between the 45 and 60 coincides with active development of plant canopy which influences disease severity and create a canopy microclimate conducive to disease development. This study suggests that Calliandra calothyrsus has the potential of improving potato production provided appropriate fungicide is used.展开更多
To evaluate the effects of chemical fertilizer combined with organic manure on apple yield,quality and soil fertility,an experiment was conducted in an apple orchard on the Loess Plateau of China.Six treatments,i.e.,1...To evaluate the effects of chemical fertilizer combined with organic manure on apple yield,quality and soil fertility,an experiment was conducted in an apple orchard on the Loess Plateau of China.Six treatments,i.e.,1)no nitrogen(N)with chemical phosphorus(P)and potassium(K)(PK),2)no P with chemical N and K(NK),3)no K with chemical N and P(NP),4)N,P and K chemical fertilizers only(NPK),5)swine manure(M)only(M),and 6)half chemical fertilizers combined with half swine manure(NPKM)were included with three replications for each.The NPKM treatment achieved 36.9 t/ha average annual yield,which was 42.5%greater than the yield of PK treatment.The average annual yields followed the sequence of NPKM>NPK>M>NK>NP>PK.In NPKM treatment 71.3%of the collected apples had an apple diameter greater than 80 mm compared with 58.2%,41.5%and 37.2%in NK,PK and NP treatments,respectively.The sugar to acid(S:A)ratio was the greatest in NPKM treatment.The results of Vitamin C,soluble solid and firmness showed that NPKM treatment had the highest values.The concentration of soil organic carbon(SOC)in the 0 to 20 cm depth of soil was significantly affected by addition of M.Compared to the antecedent soil properties,the SOCS in the NPKM and M treatments were increased by 28.8%,29.4%,and TN contents were 56.5,49.8%more for soil at 0-20 cm depths,respectively.The major soil nutrients of N,P and K were also significantly increased by M and NPKM treatments in surface soil for five years.The data support the conclusion that,for a production of 35-40 t/ha in an apple orchard on the Loess Plateau of China,the 25-30 t/ha organic manure,160-200 kg/ha N,100-150 kg/ha P2O5 and 120-160 kg/ha K2O were the most suitable fertilizer application.The finding will be helpful for harmonious development of apple production technology,economic income increase for farmers,and improvement of the apple orchard ecosystem.展开更多
基金supported by the National Key Research and Development Program of China(2022YFD2300300)the National Natural Science Foundation of China(41907072)+1 种基金the Scientific Research Foundation of Zhejiang A&F University,China(2022LFR003)the Jiangsu Agriculture Science and Technology Innovation Fund,China(CX(21)3007).
文摘Water-saving irrigation strategies can successfully alleviate methane emissions from rice fields,but significantly stimulate nitrous oxide(N_(2)O)emissions because of variations in soil oxygen level and redox potential.However,the relationship linking soil N_(2)O emissions to nitrogen functional genes during various fertilization treatments in water-saving paddy fields has rarely been investigated.Furthermore,the mitigation potential of organic fertilizer substitution on N_(2)O emissions and the microbial mechanism in rice fields must be further elucidated.Our study examined how soil N_(2)O emissions were affected by related functional microorganisms(ammonia-oxidizing archaea(AOA),ammonia-oxidizing bacteria(AOB),nirS,nirK and nosZ)to various fertilization treatments in a rice field in southeast China over two years.In this study,three fertilization regimes were applied to rice cultivation:a no nitrogen(N)(Control),an inorganic N(Ni),and an inorganic N with partial N substitution with organic manure(N_(i)+N_(o)).Over two rice-growing seasons,cumulative N_(2)O emissions averaged 0.47,4.62 and 4.08 kg ha^(−1)for the Control,Ni and N_(i)+N_(o)treatments,respectively.In comparison to the Ni treatment,the N_(i)+N_(o)fertilization regime considerably reduced soil N_(2)O emissions by 11.6%while maintaining rice yield,with a lower N_(2)O emission factor(EF)from fertilizer N of 0.95%.Nitrogen fertilization considerably raised the AOB,nirS,nirK and nosZ gene abundances,in comparison to the Control treatment.Moreover,the substitution of organic manure for inorganic N fertilizer significantly decreased AOB and nirS gene abundances and increased nosZ gene abundance.The AOB responded to N fertilization more sensitively than the AOA.Total N_(2)O emissions significantly correlated positively with AOB and nirS gene abundances while having a negative correlation with nosZ gene abundance and the nosZ/nirS ratio across N-fertilized plots.In summary,we conclude that organic manure substitution for inorganic N fertilizer decreased soil N_(2)O emissions primarily by changing the soil NO_(3)^(−)-N,pH and DOC levels,thus inhibiting the activities of ammonia oxidation in nitrification and nitrite reduction in denitrification,and strengthening N_(2)O reduction in denitrification from water-saving rice paddies.
文摘A field experiment was conducted in the Western Highlands of Cameroon to study the effects of Calliandra calothyrsus, sterilized compost, non-sterilized compost and mineral fertilizers （NPK 11：11：22） on physical characteristics, yield components and late blight disease severity of potato （Solanum tuberosum）. A two factorial treatment combination made up of fertilization schemes and sanitary measures were laid out in a randomized complete block design （RCBD） with four replicates and 10 treatments. Data collected were subjected to a multivariate ANOVA and means separated with the Dunnett t-test with Calliandra calothyrsus considered as the main treatment. Mineral fertilizers and Calliandra calothyrsus significantly augmented stem diameter, plant height and plant vigor, total and marketable yields, despite the fact that late blight severity was high in the two treatments. The correlation matrix showed that total yield had significant and positive correlation with stem diameter （r = 0.74）, plant height （r = 0.61）, plant vigor （r = 0.61） and marketable yield （r = 0.99） and negative correlation （r = -37） with late blight severity. The increase observed is attributed to the nutrient contents of the treatments applied. Leafy prunings of C. calothyrsus increase soil organic matter which probably improves moisture retention and biological activity. The highest late blight severity recorded between the 45 and 60 coincides with active development of plant canopy which influences disease severity and create a canopy microclimate conducive to disease development. This study suggests that Calliandra calothyrsus has the potential of improving potato production provided appropriate fungicide is used.
文摘To evaluate the effects of chemical fertilizer combined with organic manure on apple yield,quality and soil fertility,an experiment was conducted in an apple orchard on the Loess Plateau of China.Six treatments,i.e.,1)no nitrogen(N)with chemical phosphorus(P)and potassium(K)(PK),2)no P with chemical N and K(NK),3)no K with chemical N and P(NP),4)N,P and K chemical fertilizers only(NPK),5)swine manure(M)only(M),and 6)half chemical fertilizers combined with half swine manure(NPKM)were included with three replications for each.The NPKM treatment achieved 36.9 t/ha average annual yield,which was 42.5%greater than the yield of PK treatment.The average annual yields followed the sequence of NPKM>NPK>M>NK>NP>PK.In NPKM treatment 71.3%of the collected apples had an apple diameter greater than 80 mm compared with 58.2%,41.5%and 37.2%in NK,PK and NP treatments,respectively.The sugar to acid(S:A)ratio was the greatest in NPKM treatment.The results of Vitamin C,soluble solid and firmness showed that NPKM treatment had the highest values.The concentration of soil organic carbon(SOC)in the 0 to 20 cm depth of soil was significantly affected by addition of M.Compared to the antecedent soil properties,the SOCS in the NPKM and M treatments were increased by 28.8%,29.4%,and TN contents were 56.5,49.8%more for soil at 0-20 cm depths,respectively.The major soil nutrients of N,P and K were also significantly increased by M and NPKM treatments in surface soil for five years.The data support the conclusion that,for a production of 35-40 t/ha in an apple orchard on the Loess Plateau of China,the 25-30 t/ha organic manure,160-200 kg/ha N,100-150 kg/ha P2O5 and 120-160 kg/ha K2O were the most suitable fertilizer application.The finding will be helpful for harmonious development of apple production technology,economic income increase for farmers,and improvement of the apple orchard ecosystem.
