Analysis on Soil Nutrients and Formulated Fertilization Recommend of Rapeseed in Linxiang County,Yunnan Province

Yingxue ZHAO,Jinghua YANG,Jianxin WANG,Yao LU

1.Soil and Fertilizer Station of Linxiang Agricultural Bureau,Lincang 677099,China;

2.Institute of Agricultural Resources&Environment,Yunnan Academy of Agricultural Sciences,Kunming 650205,China

Situated in southwest of Yunnan Province (23°24′-24°26′N and 99°45′-100°26′E),Linxiang District,Lincang Prefecture,is one of ten rapeseed-producing bases in Yunnan Province and a center of Lincang City,in terms of transportation,information or politics.The lowest altitude is 730 m,and the highest at 3 430 m.Furthermore,annual mean temperature reaches 17.2℃,annual mean precipitation is 1 178 mm,relative humidity is 73%,and frost-free period lasts for 290 d.Linxiang District consists of 10 villages,towns or subdistrict offices,and Brassica napus is widely grown in most areas,except of Pingcun Village.In addition to that,rapeseed area always maintains over 3 400 hm2[1].

Soil fertility is the ability of a soil to supply plant nutrients and it is a comprehensive index evaluating soil productivity.What’s more,soil nutrients lay foundation for soil fertility and only by grasping of soil fertility could a virtuous circle of a soil environment be maintained and agricultural sustainable development be accomplished[2-3].Recently,rapeseed industry develops fast in Linxiang District,but fertilization is generally conducted blindly without consideration of soil fertility,resulting in declining of fertilization effect,unbalance of soil nutrients,degradation of soil quality,as well as increasing cost and decreasing quality of rapeseed.Therefore,it is important to ex-plore soil nutrients in rapeseed fields in Linxiang District,and propose suggestions on cultivation and soil improving,as well as fully exploitation of soil productivity,in order to facilitate income increase from rapeseed growing and advance sustainable development of rapeseed industry.

Materials and Methods

Sampling of soils

The test collected 586 soil samples from Boshang Town and Quannei Village,Linxiang District,and soil samples were collected as per local landforms,altitude,soil type and rapeseed area,as well as ecological conditions and fertility.

Specifically,the sample depth was in 0-20 cm,and collected according to S-shape route.In general,sols from 10 sites were sampled to prepare a mixed sample.In order to reflect practical nutrients and fertilizer supply capacity in the test field,soils were sampled from the end of September to early October during 2009-2012,when rapeseed was not applied with base fertilizer or transplanted after harvest of preceding crop.Analysis of soil nutrients

The sampled soils were dried in room and sift with a sieve (1 mm)for inspection and organic matter,pH value,alkali-hydrolyzale nitrogen,Olsen-P,available K,and water-soluble B were analyzed.All assay items were conducted as laboratory methods[4],as follows:soil organic matter was measured as per the potassium dichromate method-heating method;alkalihydrolyzale nitrogen was by alkaline hydrolysis diffusion method;Olsen-P was by 0.5mol/L NaHCO3digestioncolorimetry by molybdenum blue method;available K was by 1 mol/L NH4OAC digestion-flame photometer method;soil pH was by potentiometry with water-to-soil ratio at 2.5∶1;watersoluble B was by digestion in boiling water-curcuma colorimetry.

Fertilization calculation as per formula

The calculation equation of formula fertilization and coefficients were all conducted as per reference[5].

Calculation of nutrient of rapeseed

The quantity of N (P2O5and K2O)from rapeseed(kg/hm2)targeted yield(kg/hm2)×N(P2O5and K2O)from rapeseed(%).

The quantity of nutrients supplied by soilsThe quantity of N can be supplied by soils(kg/hm2)=alkali-hydrolyzable nitrogen (mg/kg)×correction factor at 0.072 (0.15×0.8×0.6)×15;the quantity of P2O5can be supplied by soils(kg/hm2)=Olsen-P of soil(mg/kg)×correction factorat0.06(0.15×0.8×0.5)×15;the quantity of K2O can be supplied by soils (kg/hm2)=available K (mg/kg)×correction factor at 0.12(0.15×0.8×1.0)×15.

The quantity of additional nutrients suppliedThe quantityofP2O5should be applied (kg/hm2)=(The quantity of P2O5from rapeseed-The quantity of P2O5can be supplied by soils)/use ratio of P fertilizer(%).

The differences of N and K2O from rapeseed and the quantity can be supplied by soils:the quantity of N/K2O should be applied additionally(kg/hm2)=(the quantity of N/K2O×(coefficient of N at 0.4 and of K2O at 0.2)/the use ratio of N/K2O(%).

Results and Analysis

Analysis of pH value and acid soil management in rapeseed-producing regions in Linxiang District

As shown in Table 1-Table 2,average of soil pH in rapeseed-producing regions in Linxiang District was 5.5,with minimum at 4.2 and maximum at 6.9,of which 53.4%of pH value were below 5.5 and 44.4%samples kept in the range of 5.5-6.6.It can be concluded that soils in rapeseed-producing region in Linxiang District are generally acid soils or strong acid soils.

Researches available indicated rapeseed is much sensitive to soil acidity.The suitable range of pH is 6-7[6]and the suitable pH of red soils for rapeseed is from 5.9-7.3[7].In rapeseed producing regions in Linxiang,most soils keep the value of pH below 5.5.Therefore,itis necessary to strengthen soil acidity.At first,it is important to pay attention to the type of N fertilizers,for ammonium nitrogen fertilizer is a key factor causing acceleration of soil acidity.It is notable that the effects of ammonium nitrogen fertilizer tend to be volatile upon the fertilizer types.For example,(NH4)2SO4and(NH4)H2PO4show the strongest effect in soil acidification,followed by(NH4)2HPO4,and urea and ammonium nitrate are of the least effect[8].Meanwhile,fused calcium-magnesium phosphate can be applied to improve soil acidity,replacing superphosphate[9].Furthermore,the use of organic matter,especially for biochar[10-11],would considerably improve soil acidity.Additionally,the application of lime and limestone flour is a traditional way to improve soil acidity.According to the effects of limes on acid soils,rapeseed growth and yield,it is recommended to use Ca(OH)2powder at 1 125-1 687.5 kg/hm2,CaCo powder at 1 500-2 250 kg/hm2,CaMg[CO3]2powder at 1 500-3 000 kg/hm2[12].

Analysis on nutrient contents in soils ofrapeseed-producing regions in Linxiang

As shown in Table-Table 3,the content of organic matter in soils of rapeseed-producing regions in Linxiang averaged 35.8 g/kg,with minimum at 3.1 g/kg and maximum at 96.8 g/kg.The content of about 30%soil sampleskept over 40 g/kg,70%kept over 30 g/kg and over 90%over 40 g/kg.

Table 1 Distribution of soil pH in rapeseed-producing regions in Linxiang

Table 2 The value of soil pH and contents of nutrients in rapeseed-producing regions in Linxiang District

Table 3 Nutrients’contents of soils in rapeseed-producing regions in Linxiang District

Table 4 The quantities of nutrients at harvesting of rapeseeds and the quantities of additional fertilizers with targeted rapeseed yield at 3 750 kg/hm2

The content of alkali-hydrolyzale nitrogen averaged 160.9 mg/kg,with minimum at 15 mg/kg and maximum at 381 mg/kg.Specifically,the content of about 60%soil samples maintained over 150 mg/kg,and 90%over 90 mg/kg.In terms of available P,the content averaged 43.6 mg/kg,with minimum at 2.7 mg/kg and maximum at 117.9 mg/kg;the content of about 60%samples exceeded 40 mg/kg,and 90%exceeded 20 mg/kg.The content of available K averaged 161.8 mg/kg,with minimum at 23 mg/kg and maximum at 796 mg/kg;the content of 20%samples was over 200 mg/kg,of 70%kept over 100 mg/kg,and 30%kept in the range of 40-100 mg/kg.

As for water-soluble B,the content averaged 0.49 mg/kg,with minimum at 0.04 mg/kg and maximum at 2.17 mg/kg.The contents of 60%samples were lower than 0.5 mg/kg,of 40%were in the range of 0.5-1 mg/kg,and the content of only 5%sample was higher than 1 mg/kg.

N,P and K fertilizers to be applied in rapeseed-producing regions in Linxiang District

As shown in Table 4,it can be concluded from average contents of N,P and K in rapeseed-producing regions in Linxiang District that soils could supply N,P2O5,and K2O at 174,39.3 and 291 kg/hm2,respectively.In practical production,the targeted yield of rapeseed in the producing region is 3 750 kg/hm2.According to statistics in Yunnan Soil and Fertilizer Station,N,P2O5and K2O from rapeseed at 100 kg reach 3.92,1.74 and 4.27 kg,respectively and it can be computed that the quantities of N,P2O5and K2O from rapeseed in the test were 147,65.25 and 160.2 kg/hm2.It can be concluded that the quantities of N and K2O from rapeseeds were lower compared with the quantities supplied by soils,and the quantity of P2O5was higher.

The use rates of N,P2O5and K2O were 19.7%,13.5%and 16.9%,respectively,and itcomputed that total applied quantity of additional N,P2O5and K2O were 300,195 and 195 kg/hm2.As per farmyard manure applied at 15 000 kg/hm2,the average contents of N,P2O5and K2O were 1.41%,0.7%and 1.26%,respectively and the use rates of the season were 30%,40%and 60%.Farmyard manures could supply N,P2O5and K2O at 60,45 and 120 kg/hm2for rapeseeds,and it can be concluded that additional fertilizers of N,P2O5and K2O should be applied at 240,150 and 75 kg/hm2.

Discussions

N,P and K are three necessary nutritional elements required by rapeseed,which would considerably improve rapeseed yield and facilitate nutrient absorption[13].It is researched that the optimal proportions of N,P and K of rapeseed at 3 750 kg/hm2are N 181.5-221.25 kg,P2O5815-106.95 kg and K2O 98.1-125.1 kg[14-15].According to research of Guo’s[16],the optimal quantities of N,P and K were 276.75,87.15 and K2O 77.85 kg/hm2and the yield can be accomplished in the range of 3 000-3 360 kg/hm2.Li[17]explored that N,P2O5and K2O should be applied at 240,72 and 60 kg/hm2in order to achieve yield at 3 450 kg.In conclusion,N and K2O quantities to be applied as additional fertilizers are similar to the research,but the quantity of P2O5is lower compared with the research,because more attention is paid to N and K fertilizers in rapeseed-producing regions in Linxiang.The result is that soils could supply more N and K2O quantities compared with thosebrought at rapeseed harvest,but the supply of P2O5is lower,taing up to 60%of that brought by rapeseed harvest.Meanwhile,the use rates of N and K fertilizers were far lower in the research compared with the rates of the research conducted by Zou[18]at 34.2%and 36.9%.

Bis a necessary and sensitive trace element required by rapeseed.In Linxiang,the content of water-soluble N in soils is generally lower,and the average and the content of 60%soil samples kept below 0.5 mg/kg.Specifically,13.8%soils are seriously short of B (＜0.25mg/kg),43.4%soils are slightly short of B ((0.25-0.5)mg/kg),and 39%soils are potentially short of B (0.5-1 mg/kg).Hence,it is important to increase application of N in rapeseed-producing regions in Linxiang.It is also researched that rapeseed yield can be improved by guaranteeing the content of available B in soils below 0.5 mg/kg,borax applied at 7.5-15 kg/hm2as basal application[19]or applying fluid B fertilizer at 13.5 kg/hm2in bolting stage[20].

Conclusions

In summary,with soil acidity improved,it is recommended to apply hydrated lime powder at 1 125-1 687.5 kg/hm2,CaCO powder at 1 500-2 250 kg/hm2,and dolomite dust at 1 500-3 000 kg/hm2.With consideration of nutrients in soils of rapeseed-producing region in Linxiang,it is recommended to strengthen farmyard fertilizers as base fertilizers over 15 000 kg/hm2;urea can be applied as N fertilizer,of which 75-150 kg/hm2can be applied as base fertilizer in transplanting stage,150 kg/hm2seedling-facilitating fertilizers can be applied 15-18 d after transplanting,and applied in bolting stage at 150-225 kg/hm2according to soil fertility and plant growth.The alkaline calcium magnesium phosphate(P2O520%),alternating superphosphate,was applied with about 750 kg/hm2.Sulfuric acid potassium(K2O 50%)was applied with about 150 kg/hm2.About 7.5 kg/hm2borax was applied into soil as basal fertilizer,while spraying 7.5 kg/hm2fluid boron at the bolting stag.

[1]BAO LQ(包丽琼).High-yielding and highly-efficient production technology of rapeseed in Linxiang District(临翔区油菜高产高效生产技术)[J].Seed Science&Technology(种子科技),2012,5:46-47.

[2]ZHENG LC(郑立臣),YU WT(宇万太),MA Q(马 强),et al.Advances in the integrated evaluation of farmland fertility(农田土壤肥力综合评价研究进展)[J].Chinese Journal of Ecology(生态学杂志),2004,23(5):156-161.

[3]LUO DQ(骆东奇),ZI J(自 洁),XIE DT(谢德体).Research on evaluation norm and method of soil fertility(论土壤肥力评价指标和方法)[J].Soil and Environmental Sciences(土壤与环境),2002,11(2):202-205.

[4]BAO SD (鲍士旦).Soil agricultural chemistry analysis(the 3rd edition)(土壤农化分析 (第三版))[M].Beijing:China Agriculture Press(北京:中国农业出版社),2000.

[5]National Soil Fertility Station(全国土壤肥料总站肥料处).Formula fertilization of vegetables(蔬菜配方施肥)[M].Beijing:Agriculture Press(北京:农业出版社),1990.84-86.

[6]MENG TF(孟踢福),WU YW(吴益伟),SHUI JG(水建国),et al.Effect of liming on soil acidity and seed yield of rapeseed(施用石灰对红壤旱地土壤酸度和油菜产量的影响)[J].Chinese Journal of Oil Crop Sciences(中国油料),1997,17(2):39-43.

[7]MENG CF(孟赐福),FU QL(傅庆林),SHUI JG(水建国),et al.Effects of soil acidity on growth and yield of soybean and rapeseed(土壤酸度对大豆、油菜生长和产量的影响)[J].Scientia Agricultura Sinica(中国农业科学),1994,27(3):63-70.

[8]XU RK(徐仁扣),Coventry DR.Soil acidification as influenced by some agricultural practices(某些农业措施对土壤酸化的影响)[J].Agro-environmental Protection(农业环境保护),2002,21(5):385-388.

[9]CHEN JJ(陈建军),LU QY(陆泉宇),JIANG YM(蒋毅敏),et al.The improvement effect of alkali fertilizer on acid soil(施用碱性肥料对酸性土壤改良效果初报)[J].Journal of Guangxi Agriculture(广西农学报),2012,27(6):18-20,78.

[10]ZHANG X(张 祥),WANG D(王 典),JIANG CC(姜存仓),et al.Biochar and research advances of biochar in acidic soil improvement(生物炭及其对酸性土壤改良的研究进展)[J].Hubei Agricultural Sciences(湖北农业科学),2013,52(5):997-1000.

[11]YUAN JH(袁金华),XU RK(徐仁扣).Research progress of amelioration effects of biochars on acid soils(生物质炭对酸性土壤改良作用的研究进展)[J].Soils(土壤),2012,44(4):541-547.

[12]HU DC(胡德春),LI XS(李贤胜),SHANG J(尚健),et al.Influences of various modifiers on acidity of brown red soil(不同改良剂对棕红壤酸性的改良效果)[J].Soils(土壤),2006,38(2):206-209.

[13]YANG Y(杨 勇),LIU Q(刘强),SONG HX(宋海星),et al.Effects of different NPK ratios on nutrients absorption,carbon and nitrogen metabolism,and grain yield of rapeseed(氮磷钾配比对油菜养分吸收、碳氮代谢产物和籽粒产量的影响)[J].Acta Agriculturae Zhejiangensis(浙江农业学报),2012,24(1):99-104.

[14]LONG JR(龙继锐),MA GH(马国辉).Effects of different N,P and K quantities and ratios on rapeseed yield in fields with rice stubble(不同氮磷钾用量及配比对晚稻茬油菜产量的影响)[J].Phosphate&Compound Fertilizer(磷肥与复肥),2007,22(3):72-73.

[15]LI JG(李家贵).Effects of N,P and K ratios on rapeseed yield and profiting(氮磷钾配施对油菜产量和效益的影响)[J].Tillage and Cultivation(耕作与栽培),2005,(3):39-40.

[16]GUO QZ(郭琼珍),CHEN KL(陈克龙),CAI YD(蔡亚东),et al.Test report on soil measurements("3414")of rapeseed fields in Hongta District(红塔区油菜测土配方施肥“3414”试验初报)[J].Yunnan AgriculturalScience and Technology(云南农业科技),2010,2:22-24.

[17]LI MF(李明福),LI YP(李玉萍),CHEN KL(陈克龙),et al.Effects of soil testing and formulated fertilization on growth and profit of rapeseed in Yuxi City(测土配方施肥对玉溪油菜生长与效益的影响)[J].Guizhou Agricultural Sciences(贵州农业科学),012,40(3):65-68.

[18]ZOU J(邹娟).Study on response of winter rapeseed to NPKB fertilization and abundance&deficiency indices of soil nutrients(冬油菜施肥效果及土壤养分丰缺指标研究)[D].Wuhan:Huazhong Agricultural University(武汉:华中农业大学).2010,12.

[19]National microelement fertilizer scientific research team(全国微肥科研协作组).Research on fertilization technology standards of Zn and B fertilizersⅢ.B fertilizer application technology standards of some major crops(几种主要农作物锌、硼肥施用技术规范的研究Ⅲ.棉花、油菜硼肥施用技术规范的研究).Soil fertilizers(土壤肥料),1989,(6):1-4.

[20]ZHU FX(朱飞翔),FU ZQ(傅志强),SHENG JK(沈建凯),et al.Effects of B fertilizers on rapeseed yield(施用硼肥对油菜产量的影响)[J].Crop Research(作物研究),2009,23(4):252-253.