【目的】研究紫色土丘陵区水稻–大白菜轮作模式下,大白菜季产量、氨挥发损失通量及影响因素,可为四川省紫色土丘陵区农业面源污染防治提供技术支撑。【方法】以大白菜为试材进行了田间试验。结合当地农民的施肥习惯,设定了6个施氮肥水平,施氮量依次为N 0、112.5、150、187.5、225、300 kg/hm~2,氮肥均等量分为基肥和追肥,分两次施用。采用密闭室连续通气法对大白菜地进行田间原位氨挥发测定。测定在基肥和追肥施用之后的第1天开始,上午9:00—10:00,下午16:00—17:00进行测定,连续测定14 d(降雨停止测定),直至检测不到氨挥发。成熟期调查大白菜产量和全氮含量。【结果】大白菜季施氮总量从0增加至300kg/hm~2时,单季氨挥发损失总量由2.27 kg/hm~2增加至22.72 kg/hm~2。基肥和追肥施氮量分别从0增加到150kg/hm~2时,基肥后氨挥发总量的变化范围为1.08 kg/hm~2到23.58 kg/hm~2,显著高于等量追肥后的氨挥发总量(0.21~2.83 kg/hm~2),这与基肥施用时期温度高于追肥施用时期的温度有关。随施氮量增加,大白菜产量增加,但从N 187.5 kg/hm~2增加至300 kg/hm~2时,大白菜产量增加不显著;氨挥发总量随施氮量增加而增加,但150kg/hm~2与187.5 kg/hm~2处理差异不显著,187.5 kg/hm~2与225 kg/hm~2、300 kg/hm~2处理之间差异显著。【结论】大白菜季氨挥发主要集中在施肥之后的两周之内,施肥量和温度是影响大白菜季氨挥发的主要因素。综合考虑产量和单季氨挥发损失总量等因素,施氮肥量为N 187.5 kg/hm~2时,大白菜的产量和环境效益最佳。
[Objectives] Nitrogen application and total straw incorporation affect spring maize yield,dry matter and nitrogen accumulation and transfer.The proper combination mode of N and straw returning was studied in this paper.[Methods] A two factors field experiment was conducted consecutively for two years in Tieling City,Liaoning Province.Two straw incorporation modes (rotary tillage and moldboard plow tillage) and five nitrogen application levels were designed.Spring maize yield,dry matter and nitrogen accumulation and transfer were analyzed.[Results] Compared with the moldboard plow tillage of straw incorporation,the dry matter,N accumulation were increased in the rotary tillage straw incorporation treatment,while there was no difference in the yield and grain nitrogen accumulation under the two straw incorporation treatments.The accumulation and contribution of dry matter and N to grain efficiency were increased in the rotary tillage straw incorporation treatment.The dry matter and N transfer,dry matter and N transfer efficiency were increased in the moldboard plow tillage straw incorporation treatment,and the contribution of dry matter and N transfer to grain efficiency pre-anthesis were 12.4％ and 44.1％.With the increase of N application rate,the yield,grain nitrogen accumulation,dry matter and N accumulation were increased.No significant increase in yield and grain nitrogen accumulation was found when the nitrogen application rate was higher than 262.5 kg/hm2.The highest dry matter and N transfer,dry matter and N transfer efficiency were obtained in the nitrogen application rate of 262.5 kg/hm2,and the contribution of dry matter and N transfer to grain efficiency were 16.7％ and 45.2％,respectively.[Conclusions] In this study,the two straw incorporation modes had similar yield and grain nitrogen accumulation,but the rotary tillage straw incorporation treatment could reduce the cost of soil tillage and greatly improve economic benefit,and the straw incorporation with nitrogen application rate of 262.5 kg/hm2 was the optimal mode.
[Objectives] The comprehensive summary and commendation on the significance, achievements and development trends in modification on conventional fertilizers for enhanced property and function in China are meaningful for making the strategies for the development of chemical fertilizer industry in the future. [Methods]Literatures relating to the progress in effect-enhancement and property modification of conventional fertilizers were collected and summarized. The development trends in the future were forecasted and some strategies were proposed.[Results] Due to its high activity of N and fixing of P in soil, the conventional N and P fertilizers have low nutrient use efficiency with consequence of serious environmental pollution in China. Therefore, it is of great significance to practice effect-enhanced modification for conventional fertilizers to upgrade their properties and functions. Currently the four measures taken in modifying the conventional fertilizers are using slow nutrient release, biological inhibitors, effect-enhancing additives and organic / inorganic combination. The products produced by employing the above four technological measures are named respectively slow-release fertilizer, stabilized fertilizer, value-added fertilizer and organic / inorganic compound fertilizer. At present, the annual production of the above four kinds of fertilizers has reached 13 million tons (commercial amount) and their annual application area reached around 27 million hectares, and the grain yield increase has reached 11 million tons. The achievement contributed greatly to promoting crop yield improvement, farmer’s income increase and environment protection. It is a systematic work to promote the practice of effect-enhanced modification for conventional fertilizers, and government policy support can help speed up the spread and expansion of the new products. [ Conclusions] The practice of effect-enhanced modification for conventional fertilizers is crucial to upgrading fertilizer property and function and consequently to increasing fertilizer use efficiency. More efforts are needed in research and policy-making support in the future in China.
A field experiment was conducted to study the growth characteristics of six radish varieties in the northwest area of Hebei Province.The results indicated that the growth vigor of Chun Guan,Chun Lei and Chun Xue-sheng were thriver than other varieties at seeding stage,especially SPAD value of Chun Xue-sheng was highest.While the growth rate of Chun Guan and Chun Xue-sheng decreased gradually after seeding stage,and their yields were decreased by 14.0%-20.6% and 31.8%-37.0% compared to the other varieties at harvest,respectively.Chun Lei and Chun Guan had moderate fresh biomass and dry matter content.The highest yield and dry-matter of root was found in Chun Hui variety,which also had the biggest ratio of root to shoot(R/S).And the second highest yield was obtained in Chun Guan 35.In addition,source and sink activity of Chun Hui and Chun Guan 35 were higher significantly than other radish varieties from seeding stage to fleshy taproot development stage.In conclusion,the growth characteristics of tested six radish varieties had significant difference,and the higher source and sink activity of Chun Hui and Chun Guan 35 from seeding stage to fleshy taproot development stage might be the key factors of obtaining higher yield.
Fertilizer use plays an important role in crop production to ensure food security in China.At the same time,the relatively low nutrient use efficiency resulted in negative impact on environment quality.Therefore,scientific use of nutrient resources and improvement in fertilizer use efficiency is an important scientific issue rated to national food security and environment quality.This review paper discussed China's basic situation with large population,limited arable land,relatively low land productivity and fragile ecosystem,analyzed fertilizer demand to meet the rapid increase in crop production,overviewed current use of organic and inorganic nutrient resources,and revealed N loss from chemical fertilizer application and its impact on environment.Based on deep understanding of the existing problems and great challenge China is facing,the authors proposed a new fertilizer recommendation strategy-"regional fertilizer rate control with adjustment at field level",developed regionalized nutrient management for small size farm operation system and precision fertilization for large scale farm operation.The current situation and existing problems in slow/controlled release fertilizers and in organic nutrient resources were also discussed.For sustained increase in crop production to support food security and to protect the environment,the technic strategy was proposed,including increase of land productivity,improvement of all nutrient resources using advanced science and technology,realization of regionalized fertilizer recommendation based on land productivity.Favorable policies and continuous financial support to fertilizer related science and technology development was also suggested.
The aim of this study is to investigate characteristics of dry matter and nitrogen(N),phosphorus(P) and potassium(K) nutrient accumulations and distributions of super-high-yield summer maize.Field experiments were conducted in 2010 and 2011 for the higher-yield corn cultivar,Denghai(DH661) and the commonly grown corn cultivar,Zhengdan 958(ZD958).The results show that the dry matter and N,P and K nutrient accumulation amounts per hectare of DH661 are 33475.53 kg,369.76 kg,117.85 kg and 285.78 kg at maturity stages of corn respectively,and compared with the ZD958,the dry matter and N,P and K nutrient accumulation amounts of DH661 are increased by 15.82%,23.72%,32.17% and 21.89% respectively.The proportions of dry matter and N,P and K nutrients in the organs of stems and leaves of DH661 are lower than those of ZD958,while the proportions of dry matter and N,P and K nutrients in the organs of grains and roots of DH661 are higher than those of ZD958.The rates of nutrients uptakes of DH661 are higher than those of ZD958 in the whole organs.The rates maintain high levels before the filling stage and decline very fast after the filling stage in the organs of stems,leaves and roots,and increase very fast after the filling stage in the grains.After the silking,DH661 still can uptake large amounts of the nutrients.As for DH661,the top dressing of the nutrients after the silking is very important to fill grains and attain higher yield.
The growth and exchange characteristics of CO2 and H2O in ginger leaves of the cultivar,Laiwu large ginger,under the same fertilizer amount were analyzed in this study.There were three treatments,conventional irrigation and fertilization(CK),drip irrigation and fertilization(T1) and integration of water and fertilizer(T2).Compared with CK,the dry biomasses of the rhizomes are increased by 11.15% and 16.95% respectively,and the dry biomass of stems and leaves in T1 and T2 have no significant differences.The integration of water and fertilizer could significantly improve the pigment content and net photosynthetic rate(Pn),reduce the transpiration rate(Tr),and increase instantaneous water use efficiency(WUE) of the ginger leaves.Compared with CK,the contents of chlorophyll and photosynthetic rates in T1 and T2 are increased by 6.77%,8.99% and 10.21%,16.23% respectively on Sep.16(At the period of rhizome enlargement),the transpiration rates in T1 and T2 are reduced by 10.19% and 9.42% respectively on Aug.20(at the period of tillering stage).The instantaneous water use efficiencies have no significant differences in T1 and T2,which are significantly higher than that of CK.At 9:00 on August 26th,the WUEs which reaches the peaks,and increased by 23.83% and 28.74% in T1 and T2.The irrigation water productivity in treatments of T1 and T2 are increased by 132.06% and 146.79%,and the fertilizer partial productivities are increased by 12.54% and 17.94%.
The research aims at the threshold of nitrogen application amount in paddy soils.A field experiment was conducted to explore the effects of different N-fertilizer applications on the yield and N use efficiency of rice,dissolved total nitrogen(DTN) in soil surface water,soil nitrogen apparent surplus rate(SNASR) of soil in northern area of Erhai Lake from 2011 to 2012.The results show that there is a quadratic relationship between the nitrogen rate and the yield.The effect of nitrogen application on the increase of the yield is significant.However,when the nitrogen application rate is higher than 304.34 kg/ha,the rice yield is decreased.The nitrogen absorption in the shoots is significantly improved with the increase of nitrogen rates,while the nitrogen harvest index(NHI) is decreased.The coefficients of correlation between the nitrogen application rates and the values of DTN concentrations in the surface water during 9 days after the N application are more than 0.609**.When the nitrogen application rates in paddy soil are from 228.26 to 304.34 kg/ha,the yields are from 9969 to 10212 kg/ha,SNASR is from 50.05% to 79.65%,and the mean values of DTN concentrations in the surface water during 9 days after N application is from 78.40 mg/L to 108.58 mg/L.The recommended nitrogen application rates for rice is from 228.26 to 304.34 kg/ha to ensure the high yield,and the environment could be acceptable to a certain degree under present production conditions.
The pig-on-litter(POL) system is a new ecological pig farming model of reducing pig wastes.The resource utilization of litters requires further investigation.A study was carried out to investigate organic matter,nitrogen,phosphorus,potassium,heavy metals,antibiotics residues,salinities and maleficent bacteria of pig litters from five pig-on-litter farms in Shandong and Jilin in China.The results show that the pig litters rich in organic matter,nitrogen,phosphorus and potash.The contents of organic matter are in the range of 42.62%-54.12%,the contents of total nitrogen are in the range of 1.54%-2.12%,the contents of total phosphorus(P2O5) are in the range of 2.24%-5.55% and the contents of total potassium(K2O) are in the range of 0.57%-2.15%.The contents of copper,zinc,chromium,arsenic,nickel,plumbum,cadmium and hydrargyrum are lower than the respective values in the organic fertilizer national standards(NY 525-2012) and control standards for urban wastes for agricultural use(GB 8172-1987).The pig litters have low environmental risks for low contents of OTC,TC and CTC.The contents of ascaris eggs and E.coli are higher than the respective values in the two standards.The ascaris eggs mortalities are in the range of 90%-94%,the numbers of E.coli are in the range of 1.29×105-2.24×106 cfus/g.Moreover,salinities are high in pig litters.Conclusion: The pig litters have the fundamental properties of organic fertilizer,and must be harmlessly processed before land utilization for biological safety risks.
In order to understand the current situation of fertilizer application and nutrients resource input problems of farmers on potato in Shaanxi province and to put forward countermeasures to solve the problems,the household survey data of the project of soil testing and formulated fertilization from 2006 to 2009 were analyzed and evaluated.There were totally 14 counties and 1890 households for the survey.The results show that in Loess plateau area of northern Shaanxi and Qin-ba mountain area of southern Shaanxi,the yields of potato are 23.0 t/ha and 15.4 t/ha,and the average yield of the whole province is 22.3 t/ha.The ratios of households of using organic manure are 99.0% and 60.6% respectively,and the average of the whole province is 95.4%.The rates of chemical fertilizer N,P2O5 and K2O are 155,78 and 13 kg/ha respectively in the whole province,which shows diminishing returns trends.Compared with the rational fertilizer rates,in Loess plateau area of northern Shaanxi and Qin-ba mountain area of southern Shaanxi,for chemical N application,43.0% and 4.0% are rational respectively,the average of the whole province is 39.4%;24.5% and 50.3% are excessive respectively,the average of the whole province is 26.9%.For chemical P2O5 application,64.6% and 16.0% are rational respectively,the average of the whole province is 60.1%;21.9% and 56.0% are excessive respectively,the average of the whole province is 25.0%.For chemical K2O application,96.9% and 93.1% are insufficient respectively,the average of the whole province is 96.6%.The current situation of household fertilization on potato in Shaanxi province is that the nitrogen and phosphate fertilizer inputs are both excessive and insufficient,and the potassium fertilizer and organic manure inputs are both insufficient.Therefore,the reasonable application of nitrogen and phosphate fertilizer,increasing potassium fertilizer and organic manure inputs and increasing top dressing fertilizers,especially in Qin-Ba mountain area of southern Shaanxi are all should be concerned for households in Shaanxi province.
Planting density is an important practice for cotton production.In order to study the effects of different planting densities on nutrition uptake and yield of transgenic cotton cultivar,Xiangzamian 8,a field experiment was conducted by using six planting densities,12000,21000,30000,39000,48000 and 57000 plant/ha,under high yield cultivated conditions in Jiangsu.The results show that the accumulative amounts of N,P and K in cotton plants are increased when the planting density is increased,while the N,P and K accumulative amounts and nutrient economic coefficients in the reproductive organs are in parabola functions,and the N,P and K accumulative amounts and nutrient economic coefficients in the reproductive organ are the highest under the 30000 plant/ha.In addition,the highest lint yield is 1610.3 kg/ha under the 30000 plant/ha.The percentages of N,P and K uptakes of cotton are the highest from the initial flowering stage to the peak flowering stage during the whole development stages,and the percentages of N,P and K uptakes from the initial flowering stage to the peak flowering stage are reduced when the planting density is increased.With the increase of plant density,the nutrient uptakes per 100 kg lint are increased,but the percentage of K uptake is reduced.Increasing the planting density reduces N,P,and K contents and enhances N,P,and K accumulations per plant in different fruit branches,but accelerates branch senescence,especially the lower branches.These results are consistent with the weights of bolls in different fruit branches.
In order to replace the winter bare fallow with green manure crop in rice cropping system in South of Jiangsu province,the field experiment was carried out to investigate the growth and nutrient characteristics of hairy vetch(Vicia villosa Roth),smooth vetch(Vicia villosa var.),milk vetch(Astragalus sinicus L.) and radish(Raphanus sativus L.) as winter green manure crops and their influences on soil mineral nitrogen before incorporation.The results showed that four kinds of green manure crops in our study all produced relatively high aboveground biomass and N,P,K nutrients accumulation,the fresh and dry biomass ranged from 24.8 t/ha to 30.7 t/ha and from 3.6 t/ha to 4.2 t/ha individually.No significant differences were found among different green manure crops.The nitrogen uptake ranged from 69.8 for radish to 136.4 kg/ha for hairy vetch.The phosphorus uptake ranged from 7.1 for radish to 11.3 kg/ha for milk vetch.The potassium uptake ranged from 117.6 for smooth vetch to 151.3 kg/ha for hairy vetch.Compared with bare fallow treatment,planting green manure crops decreased the mineral nitrogen content in plow layer soil to different extents(averagely decreased by 38.9 kg/ha).The decrease of soil mineral nitrogen content was related to significant decrease of soil nitrate nitrogen content.The soil ammonium nitrogen content had an increasing trend(averagely increased by 6.5 kg/ha).There were significant increases in ammonium nitrogen for hairy vetch and smooth vetch treatment compared with that in the bare fallow treatment.Four kinds of green manure crops in our study all suitable for planting as green manure crop in rice cropping system in South of Jiangsu province,and potentially reduced the loss risk of soil mineral nitrogen and supplied the nutrients for rice growth in the next season.
The 3414 fertilizer experiment for high fertilizer efficiency was designed to investigate N,P and K fertilizer effects on millet yield,and to simulate the optimum fertilizer recommendation rates by the established models for scientific fertilization.The results show that the application of fertilizer significantly increases the yield of millet,with a highest yield increment rate of 52.31% and with a lowest one in the case of no and excessive N which indicates a suitable application rate of N fertilizer is an important factor to influence millet yield.The combined applications of N,P and K have interactions with each other and promote millet yield with the order of NPK respectively.Any excessive application of the three factors could result in reducing the yield significantly.Through establishing the fertilizer efficiency models based on the yield,the recommended optimum fertilizer amounts of N,P2O5 and K2O are 121.61,78.09,24.23 kg/ha respectively.The suitable ratio of N∶ P2O5 ∶ K2O is 1 ∶ 0.64 ∶ 0.20.
Contents of soil total nitrogen,ammonium nitrogen and nitrate nitrogen in 0-300 cm soil layers of 6-28 year-old apple orchards were measured at 6 apple production bases of Fengxiang,Baishui,Changwu,Xifeng,Yan'an and Jingning in the Loess Plateau,and profile distributions of soil total nitrogen,ammonium nitrogen and nitrate nitrogen contents between different ages of apple orchards at different sites were analyzed and compared.The results showed that the range of soil total nitrogen contents is from 0.19 g/kg(Yan'an) to 1.28 g/kg(Baishui),the range of soil ammonium nitrogen contents is from 5.19 mg/kg(Jingning) to 39.46 mg/kg(Changwu),and the range of soil nitrate nitrogen contents is from 3.97 mg/kg(Yan'an) to 352.86 mg/kg(Baishui) at different sites and of different ages of apple orchards.There are not significant differences of soil total nitrogen contents in apple orchards at different sites except Yan'an where the content is obviously lower than those of other sites.The soil nitrate nitrogen contents are significantly different at different sites,while the soil ammonium nitrogen contents are less different.The soil total nitrogen contents in 0-60 cm soil layers of the apple orchards are obviously higher than those in the deeper soil layers.The soil nitrate nitrogen contents of old apple orchards are higher than those of young apple orchards,and at the same time the nitrate nitrogen accumulation in soil profiles below 100 cm soil layers occurs in varying degrees.The contents of soil total nitrogen,ammonium nitrogen and nitrate nitrogen of apple orchards at Yan'an are obviously lower than those at other experiment sites,which means more nitrogen fertilizer should be used appropriately to increase apple yields.However,nitrate nitrogen contents in deep soil layers of apple orchards at Fengxiang,Baishui,Changwu,Jingning and Xifeng are relatively higher,hence nitrogen fertilizer utility should be kept at present level or reduced.
In order to verify the optimum nitrogen application rate and planting density for higher yield、quality and nitrogen use efficiency of watermelon in gravel mulched field,and to provide basis for the development of rational cultivation measures,Longkang 9 representing late variety was used in this study.Under field condition,three planting densities(9525,12120,16680 plant/ha) and four nitrogen rates(0,100,200,300 kg/ha) were applied to study the interaction between nitrogen and density on yield、quality and nitrogen use efficiency of watermelon in Gravel-mulched field.The results show that planting density and nitrogen rate have significant effects on yield and quality of watermelon,but the interactive effect between them was not significant.Compared with the nitrogen rates planting density is a key factor for increasing the yield,with increased planting density,the yield of watermelon has improved,the yield of high density increased by 23.46% and 45.58% respectively compared to middle density and low density.The nitrogen rate have significant regulating effect for quality of watermelon,when nitrogen application rate increased from 0 up to 200 kg/ha,the yield and quality were also increased with nitrogen application rate,and lowered while continue to increase amount of nitrogen fertilizer,the N200 treatment increased sugar content of watermelon by 1.43% and 1.92%,and of the Vc content by 13.09% and 8.42% compared to N0 and N300.The partial factor productivity and recovery efficiency of applied N were improved for increasing yield of watermelon.In this study,taking yield、quality and nitrogen use efficiency into consideration,the appropriate plant density and nitrogen rate of watermelon in sandy field are 16680 plant/ha and N 200 kg/ha respectively,the yield、sugar content and nitrogen recovery efficiency of which were 61754 kg/ha,10.59% and 22.29%.
In a 4-year field experiment,effects of the long-term N application and straw returning on crop yield,NUE,residual Nmin and N budget are studied under wheat-corn rotation system in the Guanzhong Plain.The results show that the N application significantly increase the crop yields of winter wheat and summer maize with averages of 64.1% and 48.8% respectively,and the trends are increased at first and then decreased with N application rate increasing.The yields are not decreased in the 4-year successive harvests,though the nitrogen application rates are reduced by 27.3% for winter wheat and 55.6% for summer maize.The crop yields under the straw returning on are increased gradually with planting years.The accumulative NUEs of crops are increased with the increase of cropping rotation time and the NUEs in the four years are from 33.3% to 56.6%,which shows that the N fertilization has a carryover effect.The nitrogen application significantly enhances the residual Nmin in which the residual nitrate-N is apparently larger than the residual ammonium-N.The residual nitrate-N in 0-100 cm soil layer shows a positive relationship with the annual N fertilizer inputs.The straw returning shows no effects on mineral N residual in this experiment.The results of N budget show that the N accumulative uptakes by the crops are firstly increased and then declined,while the residual Nmin and apparent N loss are increased significantly.The straw returning has strong influences on nitrogen budgets of the rotation system,N accumulative uptakes by the crops,and the NUEs are increased by 13.0% and 26.2%,respectively.Both the apparent N loss and apparent N loss efficiency are decreased by 22.9%,while the apparent fertilizer N is kept in soil(Nmin residual) and its percentage in the straw returning treatment is not affected significantly compared with the treatment without straw returning.
This study aimed to screen multifunctional bacillus strain,to select the efficient combination of different strains and to investigate the mechanism of plant growth-promoting strain.In order to screen multifunctional bacillus strain from 9 candidate strains,the method of flat confrontation,antagonistic activity determination of fermentation filtrate,potted plant growth test,and soil nutrient and soil microbial groups analysis were used.Through the compatibility tests indoor,the optimal combination of functional bacillus strain was obtained.All bacillus strains are found with the function of inhibiting several pathogenic fungi and promoting plant growth except for B02 and B08.B04 is more efficient in promoting plant growth than other strains,and compared to the control,the total dry weights of plant are increased by 28.4% and 44.6% at the days of 30 and 60 respectively.B06 is more effective in inhibiting 8 pathogenic fungi than other strains,with R2/R1 ranging from 0.4 to 1.8,and the inhibition rate of sterile fermentation filtrate is from 66.7% to 87.5%.Besides,B01 has a role of activating N and P,B03,B04,B05 and B06 have a role of activating N and K,B07 has a role of activating K,and B09 has a role of activating N,P and K.The activated rate of N is from 8.4% to 23.2%,the activated rate of P is from 3.5% to 8.4%,and the activated rate of K is from 4.2% to 26.8%.Results of the compatibility tests indoor show that the optimal combinations are B04-B06-B07 and B01-B04-B07.The 9 bacillus strains have one or more than one functions of inhibiting pathogenic fungi,promoting plant growth,activating soil nutrient and improving soil microbial groups.The study of selecting combination of mutifunctional bacillus strain is reliable and feasible.However,application of these strains still needs to be further studied.
The appropriate values of different apple varieties' leaf nutrient elements in different areas are diverse,determination of the standard for apple leaf nutrients has guiding significance for nutrient management.The leaf nutritional element contents of Delicious apple in Gansu province were studied.The results show that the variation patterns of constant nutrition elements are smaller than those of trace elements.The contents of N,P,Ca,Mg,Zn and Mn of high yield orchards are significantly higher than those of low yield orchards,while the iron contents of high yield orchards are significantly lower than those of low yield orchards and the middle yield orchards.The K and B contents are not significant in difference orchards.According to the results of X2 test,the distributions of the N,P,K,Ca,Mg and B contents in leaves are in the normal distributions,while the contents of Cu,Fe,Mn,and Zn are in skewed distributions(X2 distribution).According to the probability classification method,the values of normally distributed characters could be divided into 5 grades which correspond to the absence values,low values,normal values,high values,and excess values of standard range of nutritional elements,and the occurrence probabilities of 1-5 grades are 10%,20%,40%,20% and 10% respective1y.The values from(X-0.5246S)to(X+0.5246S)could be the normal values of the standard ranges which are close to the average values of leaf nutritional elements in high yield orchards.The values of X2 distributed characters could be corrected by the average values of leaf nutritional elements in high yield orchards.In view of the above,compared with the other standards,the standard ranges of apple leaf nutritional elements of delicious apple in Gansu province are that the characteristics of N,P,K,Mn,Zn,B are normal,Ca,Mg,Cu are higher,and Fe is highest.
This article summarized the research progresses upon cell wall component changes and physiological view of root elongation under aluminum stress.Inhibition of root elongation is the prominent symptom of aluminum toxicity.Previous studies demonstrated that changes of cell wall chemical components induced by Al are the dominating reason.We explicate that Al-induced changes of cell wall components(e.g.,lignin,callose,cellulose,hemicellulose,pectin and glycoprotein) and relative metabolic enzymes trigger the decrease of cell wall elasticity,thus inhibit cell elongation,which eventually results in the inhibition of root elongation.Finally,due to the lack of systematic study on individual plant,comprehensive and rational explanations on Al-induced inhibition cannot be achieved.We suggest to focus on the contribution of individual cell wall component on Al-induced root inhibition.In order to tackle the Al-induced problems of production and quality on staple food crops,a systematic studies need to be implemented.
A field experiment was conducted to study the effects of different organic fertilizer application on growth,water use efficiency and nutritional quality of fruits of pear-jujube in the Loess Plateau.The results show that compared with the control treatment(CK),the bearing branch,leaf area and chlorophyll contents of different fertilizer treatments are significantly different(P0.05),and the jujube hanging and leaf area under the soybean cake fertilizer(SC) treatment are 20.17 cm and 1246 mm2/leaf which are increased by 34.00% and 44.46% respectively.Compared with the CK the leaf area index(LAI) and density of canopy light interception of each treatment are significantly different(P0.05) and the order is biogas manure(BM)chemical fertilizer(CF) sheep manure(SM) soybean cake fertilizer(SC) CK.The photosynthetic rate(Pn) and stomatal conductance(Gs) are improved,and the maxima of Pn and Gs are 22.38 μmol/(m2·s) and 0.5014 mmol/(m2·s) respectively under the BM treatment.The instantaneous water use efficiency of SC is up to 3.30% under the different fertilization which is increased by 1.29 percent point compared with the CK.The soil water content of the SC treatment is increased significantly under all organic fertilization.The yields are all increased significantly,and the yields are increased by 138.52%,49.57% and 75.90% under the soybean cake fertilizer,sheep manure and biogas manure respectively.The nutritional quality of fruit is increased significantly.The water content of the SC treatment is increased significantly by 9.15 percent point compared with the CK.The nutritive indexes such as total soluble solids(TSS),total soluble solids/titrable acids(TSS/TA),vitamin C and total flavones are increased compare with the CK,and the titrable acidity(TA) contents are BMCFSMSCCK.In general,the organic fertilization can effectively promotes the growth,development,yield and fruit quality of pear-jujube in the Loess Plateau and the effect of the soybean cake fertilizer is the most significant.
