豆類作物施用氮肥在生物學(xué)與經(jīng)濟(jì)學(xué)上的意義

1、豆類作物施用氮肥在生物學(xué)與經(jīng)濟(jì)學(xué)上的意義豆類作物施用氮肥在生物學(xué)與經(jīng)濟(jì)學(xué)上的意義PaulPaulW.W.SingletonSingletonNantaknNantaknBoonkerdBoonkerdJamesJamesR.R.HollyerHollyer夏威夷大學(xué)熱帶農(nóng)業(yè)和人類資源學(xué)院NifTAL項(xiàng)目Suranaree技術(shù)大學(xué)農(nóng)業(yè)生物技術(shù)系夏威夷大學(xué)熱帶農(nóng)業(yè)和人類資源學(xué)院農(nóng)業(yè)和資源經(jīng)濟(jì)系1.引言Introduction豆類作物同化氮素

2、有兩種形式，它不僅可以同化來自土壤及肥料的無機(jī)氮，也可以通過生物固氮從大氣中捕獲氮?dú)?。生物固氮過程是利用植物根瘤中產(chǎn)生的細(xì)菌酶把N2還原成有效形態(tài)。根瘤是共生細(xì)菌（根瘤菌屬）侵入根毛后形成的，豆類作物光合作用為共生固氮共生體提供能量。Legumeshavetwomodesofnitrogenassimilation.AlthoughlegumesassimilatemineralNfromsoilfertilizersourcesthe

3、yalsocaptureNfromtheatmospherethroughbiologicaldinitrogenfixation(BNF).TheBNFprocessreducesN2toplantavailablefmsusingbacterialenzymesproducedwithinrootnodules.TherootnodulesarefmedafterthesymbioticbacteriaRhizobiuminvade

4、sroothairs.LegumephotosynthesisprovidestheenergythatdrivestheBNFsymbiosis.豆類作物依靠生物固氮作為氮源的程度取決于以下因素的相互作用：TheextenttowhichlegumesrelyonBNFasanNsourceisdeterminedbyaninteractionbetween:1)達(dá)到作物產(chǎn)量潛力所需的氮素總量；1)totalamountofNrequ

5、iredtomeetcropyieldpotential2)土壤中有效態(tài)無機(jī)氮的數(shù)量；2)amountofmineralNavailableinthesoil3)形成豆類作物根系根瘤的根瘤菌的效果。3)effectivenessofrhizobiafmingnodulesonlegumeroots大多數(shù)豆類作物管理策略目的是最大限度地促進(jìn)生物固氮。在作物生長期間，生物固氮過程直接受土壤礦質(zhì)氮供應(yīng)比例的抑制，要加大生物固氮量，豆類作物必須

6、利用少量礦質(zhì)氮以在生物固氮全面發(fā)揮前維持幼苗生長。MostlegumemanagementstrategiesaimtomaximizeBNF.DuringmostofcropdurationthelegumeBNFprocessisinhibitedindirectproptiontosoilsupplyofmineralN.TomaximizeBNFhoweverlegumesmustassimilateasmallamountof

7、mineralNtosustainearlycropgrowthpritofullexpressionofBNF.ofNmanagementoflegumes.FurtheritevaluatestheeconomiccostsbenefitsofNmanagementoptionsflegumesinChinaincludingopptunitycostsofNfertilizeruseinrelationtononNfertiliz

8、erinputs.2.豆類作物對(duì)氮的需要和吸收NitrogenRequirementsUptakebyLegumes2.1豆類作物在農(nóng)業(yè)上的重要性Imptanceoflegumesinagriculture籽用豆類是世界農(nóng)業(yè)中第二重要的作物。通過直接食用和轉(zhuǎn)化為動(dòng)物產(chǎn)品，它們是重要的食物蛋白的來源。在許多發(fā)展中國家豆類蛋白占蛋白質(zhì)消耗的大部分；在一些發(fā)達(dá)國家及那些經(jīng)濟(jì)快速增長較不發(fā)達(dá)國家，對(duì)豆類蛋白需求的增長速度超過了對(duì)谷物需要的增長。

9、收入的增加加速對(duì)動(dòng)物蛋白與豆類作物這種動(dòng)物原料的需求。在很多情況下，豆類作物生產(chǎn)的增加反映了畜牧生產(chǎn)的變化。例如，在1980~1992年間，中國畜牧業(yè)迅速增長，在同一時(shí)期，大豆及花生生產(chǎn)也提高了，豆類作物生產(chǎn)的增加幾乎完全是來自管理措施的改進(jìn)。改進(jìn)作物管理與產(chǎn)量潛力的一個(gè)標(biāo)志是磷肥與鉀肥的施用量的急劇增加。本文將說明管理的改進(jìn)與豆類作物高產(chǎn)是農(nóng)民從生物固氮中獲得最大利益的條件。Grainlegumesarethesecondmostim

10、ptantcropinwldagriculture.Theyareanimptantsourceofdietaryproteinthroughdirectconsumptionconversiontoanimalproducts.Inmanydevelopingcountrieslegumeproteinaccountsfamajptionofproteinconsumption.Indevelopedcountriesinthosel

11、esserdevelopedcountriesthatareexperiencingrapideconomicgrowthdemflegumeproteinisacceleratingfasterthandemfcereals.Risingincomesacceleratedemfanimalproteinlegumecropstherawmaterialsfanimalindustries.Inmanycasesincreasedle

12、gumeproductionmirrschangesinanimalproduction.FexampleanimalproductioninChinaincreasedrapidlybetween19801992Inthesameperiodsoybeangroundnutproductionalsorose.Increasedlegumeproductionwasalmostentirelyduetohigheryieldsfrom

13、improvedmanagement.OneindicatofimprovedcropmanagementyieldpotentialisthedramaticincreaseinPKfertilizerconsumptioninChina.Thispaperwillshowimprovedmanagementhigheryieldsoflegumecropsarepreciselytheconditionswherefarmersca

14、ngainthelargestbenefitfromlegumeBNF.2.2豆科作物吸收的總氮量Totalnitrogenassimilationbylegumes大多數(shù)豆類作物的產(chǎn)量及總生物量低于谷類作物，但豆類種子及葉片中的蛋白質(zhì)含量卻高幾倍。蛋白質(zhì)本質(zhì)上就是帶有氨基的碳鏈。豆類作物組織高濃度的蛋白質(zhì)就意味著對(duì)氮素同化的高度需求。Whiletotalbiomassyieldofmostlegumecropsislowerthanc

15、erealslegumeseedleafproteinconcentrationscanbeseveraltimeshigher.Sinceproteinsareessentiallycarbonchainswithattachedaminogroupsthehighconcentrationofproteininlegumetissuestranslatesintoahighdemfnitrogenassimilation.豆類作物的