Effect of different fertilization on spring cabbage (<i>Brassica oleracea L. var. capitata</i>) production and fertilizer use efficiencies

Just after transplanting, the vegetable has difficulty in nutrients uptake. To explore the effect of different fertilization on spring cabbage (Brassica oleracea L. var. capitata) production and fertilizer use efficiencies, this experiment consisting of six treatments was implemented and divided into three groups: 1) no fertilizer (NF) and vegetable planting fertilizer (VPF);2) conventional fertilizer (CF) and conventional fertilizer + vegetable planting fertilizer (CVPF);3) reduced fertilizer application (RFA) and reduced fertilizer application + vegetable planting fertilizer (RVPF). The results of this experiment indicated that the yields of spring cabbage treated by VPF increased by 38.20% in VPF, 16.00% in CVPF and 20.40% in RVPF than their controls respectively. Additionally, the VPF helped improve the total and economic yields of the spring cabbage in all groups, and the economic benefits increased by 38.21% in VPF, 15.97% in CVPF and 20.42% in RVPF than their controls respectively. Finally, the VPF was of benefit to spring cabbage to exploit the soil nutrients and helped improve the chemical fertilizer use efficiencies. Therefore, it is an efficient, economical and ecological fertilization for vegetable production to apply chemical fertilizers in combination with VPF.

Combined application of organic manure and chemical fertilizers stabilizes soil N-cycling microflora

Straw and manure are widely applied to agricultural systems,and greatly shape soil N-cycling microflora.However,we still lack a comprehensive understanding of how these organic materials structure soil N-cycling microbial communities.In this study,metagenomic analysis was performed to investigate the compositional variation in N-cycling microbial communities in a 30-year long-term experiment under five fertilization regimes:no fertilization(Control),chemical fertilization only(NPK),and NPK with wheat straw(NPK+HS),pig manure(NPK+PM),and cow manure(NPK+CM).Long-term NPK application differentially changed N-cycling gene abundance and greatly altered N-cycling microbial community structure.NPK+HS resulted in a similar pattern to NPK in terms of gene abundance and community structure.However,NPK+PM and NPK+CM significantly increased most genes and resulted in a community similar to that of the Control.Further analysis revealed that serious soil acidification caused by long-term NPK fertilization was a major factor for the variation in N-cycling microbial communities.The addition of alkaline manure,rather than wheat straw,stabilized the N-cycling microbial community structure presumably by alleviating soil acidification.These results revealed the strong impact of soil acidification on microbial N-cycling communities and illustrated the possibility of resolving nitrogen-related environmental problems by manipulating pH in acidified agricultural soils.

Effect of fertilization patterns on the assemblage of weed communities in an upland winter wheat field

Aims Understanding the response of farmland weed community assembly to fertilization is important for designing better nutrient management strategies in integrated farmland ecological systems.Many studies have focused on weed characteristics,mainly crop–weed competition responses to fertilization or weed communities alone.However,weed community assembly in association with crop growth is poorly understood in the agroecosystems,but is important for the determination of integrated weed management.Biodiversity promotes ecosystem productivity in the grassland,but whether it applies to the agroecosystems is unclear.Based on an 11-year field experiment,the cumulative effects of different fertilization patterns on the floristic composition and species diversity of farmland weed communities along with wheat growth in a winter wheat–soybean rotation were investigated.Methods The field trial included five fertilization patterns with different combinations of N,P and K fertilizers.Species composition and diversity of weed communities,aboveground plant biomass and nutrient accumulation of weeds and winter wheat,light penetration to the ground surface and wheat yield were measured at each plot in 2009 and 2010.Multivariate analysis,regression and analysis of variance were used to analyze the responses of these parameters to the different fertilization treatments.Important Findings Four dominant weeds(Galium aparine L.,Veronica persica Poir.,Vicia sativa L.and Geranium carolinianum L.)accounted for~90%of the total weed density in the 2 years of experimental duration.The residual weed community assembly was influenced primarily by topsoil available nutrients in the order P>N>K.Competition for nutrients and solar radiation between crops and weeds was the main indirect effect of fertilization on the changes in weed community composition and species diversity.The indices of species diversity(species richness,Shannon–Wiener,Pielou and Simpson indices)showed significant linear relationships with wheat yield.The balanced fertilization treatment was more efficient at inhibiting the potential growth of weeds because of solar radiation being intercepted by wheat.These results support the conclusion that wheat yield is favored by balanced fertilization,whereas the weed community is favored by PK fertilization in terms of density and diversity.However,the negative effects on wheat yield may be compromised by simultaneous positive effects of weed communities in the fertilization treatments,for instance,the NP and NK treatments,which are intermediate in terms of increasing wheat production and to a level maintaining a diverse community.

AOA and AOB communities respond differently to changes of soil pH under long-term fertilization

Archaeal and bacterial ammonia-oxidizers drive the first step of nitrification,ammonia oxidation.Despite their importance,the relative contribution of soil factors influencing the abundance,diversity and community composition of ammonia oxidizing archaea(AOA)and bacteria(AOB)are seldom compared.In this study,the AOA and AOB communities in soils from a long-term fertilization experiment(which formed gradients of pH and nutrients)were measured using 454 pyrosequencing of the amoA gene.Results showed that both AOA and AOB communities were influenced by fertilization practice.Changes of AOA abundance,diversity and community structure were closely correlated with a single factor,soil pH,and the abundance and diversity of AOA were lower under the acidified treatments.By contrast,AOB abundance was higher in the acidified soil than in the control soil while AOB diversity was little impacted by soil acidification,and both the abundance and diversity of AOB were most highly correlated with soil carbon and available phosphorus.These results indicated that AOB diversity seemed more resistant to soil acidification than that of AOA,and also suggested that AOB have greater ecophysiological diversity and broader range of habitats than AOA in this lime concretion black soil,and the potential contribution of AOB to ammonia oxidation in acid environments should not be overlooked.

Effect of long-term fertilization on bacterial communities in wheat endosphere

Fertilization has been shown to exert a significant influence on soil microorganisms and directly and indirectly influences plant growth and survival in agroecosystems. However, it is unknown whether fertilization affects endophytic microbial communities, which are ubiquitous and intimately associated with plant growth and health. Herein, we investigated endophytic bacterial communities in wheat leaves and roots under different long-term fertilization regimes,including NPK chemical fertilizer and NPK chemical fertilizer combined with wheat straw, pig manure, or cow manure. Endophytic bacterial community composition considerably differed in leaves and roots. Although different fertilization treatments did not affect the endophytic bacterial species richness or phylogenetic diversity in either leaves or roots, the community composition was significantly altered, particularly in roots. The endophytic bacterial co-occurrence network in leaves was more complex and stable than that in roots. Furthermore, many of the keystone species that were identified by their topological positions in the co-occurrence networks of leaves and roots were involved in plant growth and fitness. The total relative abundance of keystone species was the highest in the NPK plus cow manure treatment in both leaves and roots. Overall, our results suggest that different fertilization regimes can strongly affect endophytic bacterial communities, and the combination of NPK fertilizer and cow manure promoted the relative abundance of the key endophytic bacterial microbiota in both leaves and roots, which might be beneficial for plants in agroecosystems.