Effects of Reduced Nitrogen Fertilization and Biochar Application on CO_2 and N_2O Emissions from a Summer Maize-Winter Wheat Rotation Field in North China

This experiment was conducted in Xinxiang, Henan from June 2013 to June 2014. Total four treatments were designed including farmers ’ common practice （F, 250 kg/hm^2）, 80% F （LF, 200 kg/hm^2）, 80% F＋biochar （LFC） and no fertilizer （CK） to measure the dynamic emissions of CO2 and N2O from a summer maize-winter wheat field by static chamber-gas chromatography method. The results showed that the soil CO2 emission was 21.8-1 022.7 mg/（m^2·h）, and was mainly influenced by soil temperature and moisture content. During the growth of summer maize, the soil CO2 emission was more significantly affected by soil moisture con-tent; and in winter wheat growing season, it was more significantly affected by soil temperature in the top 5 cm. The LF and LFC treatments significantly reduced the soil cumulative CO2 emission, especial y during the growth of winter wheat. Fertiliza-tion and irrigation were the main factors influencing the soil N2O emission. The soil N2O emission during the fertilization period accounted for 73.9%-74.5% and 40.5%-43.6% of the soil cumulative N2O emission during the summer maize-and winter wheat-growing season, respectively. The peak of emission fluxes was determined by fertilization amount, while the occurrence time of emission peak and emission re-duction effect were influenced by irrigation. The LF treatment reduced the soil cu-mulative N2O emission by 15.7%-16.8% and 18.1%-18.5% during the growth period of summer maize and winter wheat, respectively. Reduced nitrogen fertilization is an effective way for reducing N2O emission in intensive high-yielding farmland. Under a suitable nitrogen level （200 kg/hm^2）, the application of biochar showed no significant effect on the soil N2O emission in a short term. The N2O emission factors of the L and LF treatments were 0.60% and 0.56%, respectively. ln the intensive high-yield-ing farmland of North China, reducing the nitrogen application amount is an appro-priate measure to mitigate greenhouse gas emissions without crop yield loss.

Impact of Silicon,Zinc,Boron Combined with Reduced Nitrogen Fertilization on Rice Growth

Under the condition of reduced application of nitrogen fertilizer, the impact of silicor）, zinc and boron on rice growth was investigated by field experiment. The results showed that when the application amount of nitrogen fertilizer was reduced by 20%, the application of silicon, zinc and boron did not reduce the yield of rice, but reduced the incidence of panicle blast in rice and optimized the structure of rice production.

Application of Chinese milk vetch affects rice yield and soil productivity in a subtropical double-rice cropping system

Green manure can be used as a substitute for chemical fertilizer without reducing rice yield.We studied the responses of soil fertility and rice yield to different combinations of Chinese milk vetch(CMV;Astragalus sinicus L.)and chemical fertilizer in a subtropical double-rice cropping system.Our goal is to reduce chemical fertilizer use and decrease environmental contamination.Compared with the recommended rate of chemical fertilizer(CF),both early-and late-rice yields in the two treatments supplied with 15 and 22.5 Mg CMV ha^-1 plus 60%CF(represented as 60 A and 60 B,respectively)showed no significant differences while the two treatments supplied with 30 and 37.5 Mg CMV ha^-1 plus 60%CF(represented as 60 C and 60 D,respectively)showed significantly higher values.The sustainable yield index(SYI)values in the 60 C and 60 D treatments with double-rice croppong system were significantly higher than those in other treatments(P<0.05).Early-rice yield showed a significant positive relationship with the Chinese milk vetch incorporation rate.The coefficients increased annually from 2009 to 2013 and then decreased in 2014.Soil organic matter increased over time by the end of the experiment in all of the treatment groups.Soil organic matter in 60 A,60 B and 60 C showed no significant difference compared with that in CF,while soil organic matter in 60 D was significantly higher than that in CF.The slopes of soil organic matter and total nitrogen over six years were the highest in 60 C and 60 D.The soil total nitrogen content in 60 A,60 B,60 C and 60 D was higher than that in CF,but the differences were not significant(P>0.05).Therefore,a relatively high Chinese milk vetch incorporation rate(≥30 Mg ha^-1)was more effective in improving the productivity and sustainability of paddy soil.The decreased coefficients of early-rice yield and the Chinese milk vetch incorporation rate in 2014 implied that the benefits of soil fertility and rice yield created by Chinese milk vetch input may decline after five years under a continuously high rate of Chinese milk vetch incorporation.

Effects of Substitution of Organic Manure for Chemical Fertilizer on Phosphorus Accumulation and Grain Yield in Maize

In order to explore the response of maize phosphorus absorption to the appropriate proportion of organic fertilizer substitution for reduced chemical fertilizer,a field experiment with eight treatments was conducted in 2018.The eight treatments in the trial were:(1)CK;(2)M0+F;(3)M1+F1;(4)M1+F2;(5)M2+F1;(6)M2+F2;(7)M3+F1 and(8)M3+F2.In these treatments,M0,M1,M2 and M3 were organic fertilization of 0,15(low),30(medium)and 45(high)m3•hm-2,respectively.F1 and F2 indicated 20%and 40%reduction of conventional chemical fertilization.The soil nutrient content,phosphorus accumulation,dry weight,yield and yield components of maize were analyzed.The results showed that the phosphorus accumulation of maize stalks and leaves were 3.30%-43.17%and 10.98%-84.95%higher in M3+F1 treatment(20%reduction of chemical fertilizer with organic fertilizer of 45 m3•hm-2)than those in the conventional treatment(M0+F)during the maize reproductive period.At R2 stage,stalk and shoot P accumulation of M3+F1 treatment were 24.67%-43.18%and 20.34%-25.19%higher than other treatments,respectively.At V12 stage,leaf P accumulation of M3+F1 increased by 84.95%compared with other treatments.The maize yield of M3+F1 was significantly higher than that of other treatments,even though the partial productivity of the total phosphorus fertilizer of M3+F2 was the highest in the treatments.It could be found that the substitution of organic fertilizer for chemical fertilizer improved crop yield,phosphorus fertilizer efficiency and accumulation.M3+F1 treatment had the most positive effects on improving maize phosphorus accumulation and yield.

Application of Aisi Si/TE Compound Bacterial Fertilizer in Rice

[Objectives]To investigate the application effect of compound microbial fertilizer on crops.[Methods]Livestock and poultry breeding waste,rapeseed cake and peanut straw were fully decomposed,and then added with compound functional microbial inoculum to produce Aisi Si/TE(active chelated silicon/trace element)compound microbial fertilizer,which was used to conduct 10%nitrogen reduction alternative fertilization experiment on rice.[Results]The yield of rice applied with 225 kg/ha Aisi Si/TE compound bacterial fertilizer was 7203 kg/ha,increased by 5.4%,6.9%and 46.9%,respectively compared to those of rice applied with 225 kg/ha inactivated Aisi Si/TE compound microbial fertilizer,conventional fertilization and blank control(P<0.01).Application of Aisi Si/TE compound microbial fertilizer to rice improved soil organic matter and effective nutrient content and showed obvious effect of saving nitrogen and increasing yield and income.In addition,it provided a good micro-ecological environment,passivated and solidified heavy metals,effectively reduced the biological mobility of heavy metals,and greatly reduced the cadmium content in rice.[Conclusions]Application of Aisi Si/TE compound microbial fertilizer is beneficial to improving the quality of agricultural products.

Effect of Reducing Application of Chemical Fertilizers and Chemical Pesticides on Physiological Traits,Yield and Quality of Radish

This paper studied the effect of reducing application of chemical fertilizer,increasing application of functional organic fertilizer and trace elements and fully using biological pesticides on physiological traits,yield and quality of radish. The results showed that applying functional organic fertilizer and trace elements and fully using biological pesticides could help to significantly improve the radish fleshy root yield,increase soluble sugar and vitamin C content,reduce crude fiber and nitrate content,but had no significant influence on radish moisture content,glucosinolates and chlorpyrifos content in organophosphorus pesticides.

Fertilization and Catch Crop Strategies for Improving Tomato Production in North China

Overuse of fertilizers and the resultant pollution and eutrophication of surface and groundwater is a growing issue in China. Consequently, improved management strategies are needed to optimize crop production with reduced nutrient inputs. Conventional fertilization （CF）, reduced fertilization （RF）, and reduced fertilization with maize （Zea mays L.） as a summer catch crop （RF＋C） treatments were evaluated in 2008 and 2009 by quantifying tomato （Lycopersieon esculentum） fruit yield and soil nutrient balance in a greenhouse tomato double-cropping system. Fertilizer nitrogen （N） application was reduced by 37% in the RF and RF＋C treatments compared to the CF treatment with no significant reduction in fruit yield. Mean soil mineral N （Nmin） content to a depth of 180 cm following tomato and maize harvest was lower in the RF and RF＋C treatments than in the CF treatment. Residual soil Nmin content was reduced by 21% and 55% in the RF and RF＋C treatments, respectively, compared to the CF treatment. Surplus phosphorus （P） and potassium （K） contents in the RFWC treatment were significantly lower than those in the RF treatment, mainly due to additional P and K uptake by the catch crop. We concluded that for intensive greenhouse production systems, the RF and RF＋C treatments could maintain tomato fruit yield, reduce the potential for nitrate （NO3^--N） leaching, and with a catch crop, provide additional benefits through increased biomass production.

Hot Laptops May Reduce Male Fertility

电脑为人们的生活带来了无穷无尽的乐趣与便利!但是其可能产生的潜在危害又能达到什么程度呢?最近专家们发现,经常使用膝上型电脑(laptops)的男性其生育能力可能会降低。本文详细讲述了产生这种可能性的原因!想当爸爸的你一定要注意哦!

Chromosome-scale genomes provide new insights into subspecies divergence and evolutionary characteristics of the giant panda

Extant giant pandas are divided into Sichuan and Qinling subspecies.The giant panda has many speciesspecific characteristics,including comparatively small organs for body size,small genitalia of male individuals,and low reproduction.Here,we report the most contiguous,high-quality chromosomelevel genomes of two extant giant panda subspecies to date,with the first genome assembly of the Qinling subspecies.Compared with the previously assembled giant panda genomes based on short reads,our two assembled genomes increased contiguity over 200-fold at the contig level.Additional sequencing of 25 individuals dated the divergence of the Sichuan and Qinling subspecies into two distinct clusters from 10,000 to 12,000 years ago.Comparative genomic analyses identified the loss of regulatory elements in the dachshund family transcription factor 2(DACH2)gene and specific changes in the synaptotagmin 6(SYT6)gene,which may be responsible for the reduced fertility of the giant panda.Positive selection analysis between the two subspecies indicated that the reproduction-associated IQ motif containing D(IQCD)gene may at least partly explain the different reproduction rates of the two subspecies.Furthermore,several genes in the Hippo pathway exhibited signs of rapid evolution with giant panda-specific variants and divergent regulatory elements,which may contribute to the reduced inner organ sizes of the giant panda.