农田土壤磷素淋溶及其预测

农田土壤磷素淋溶及其预测第23 卷第12期2003 年12 月生态学报A CTA ECOLO G ICA S I NICAV o l. 23, N o. 12D ec. , 2003农田土壤磷素淋溶及其预测吕家珑(西北农林科技大学资源环境学院, 陕西杨凌712100)摘要: 农田土壤磷的淋溶损失, 不仅造成肥料利用率降低、农业生产成本上升, 还能引起地下和地表水体富营养化。

在综合大量中外文献的基础上, 阐述了农田土壤磷素淋溶问题的提出、淋溶对水体富营养化的贡献、淋溶液中磷素的形态及其比例、影响土壤磷素淋溶的因子、淋溶机理、预测方法, 并对农田土壤磷素淋溶及其预测作了展望。

关键词: 农田土壤; 磷; 淋溶; 预测方法Phosphorus leach in g from agr icultura l so ils and its pred ic t ion LU J ia2L ong (R esources and E nv ironm ental College, N orthw est S ci2T ech U niversity of A g ricu ltu re and F orestry ,Y ang ling , S haanx i 712100, China). A cta Ecolog ica S in ica , 2003, 23 (12) : 2689～2701.Abstract: Pho spho ru s ( P ) is an essen t ia l elem en t fo r p lan t grow th. It also is a key elem en t fo r eu t roph icat io n of w ater bodie s.T he lo ss of P from agricu ltu ral so ils no t on ly leads to a decrease in the u t iliza t io n rat io of fertilizers and an increase in the co st of agricu ltu ral p roduct io n, bu t also gives rise to the eu t r oph icat i o n of su rface w ater and ground w ate r. Eu t r oph icat i o n, cau sed by P en richm en t, first cam e to the fo re in the 1960s, mo st no tab ly in the Great L akes reg io n of the U SA and Canada. In the fo llow ing decade, a ho st of o ther w ater bodies, suffering from varying degrees of pho spho ru s en richm en t, w ereiden t if ied around the w o rld. T here are tw o w ays fo r pho spho ru s to en ter w ater bodies2po in t sou rce andnon2po in t sou rce. H um an beings did no t pay enough atten t io n to P lo ss from agricu ltu ral land to w ater bodies un t il the 1960s becau se of its lim ited movem en t in so ils. P m ay be lo st from agricu ltu ral land to w ater bodies by several p rocesse s. T hese include ero sio n, su rface runoff and leach ing. It is repo rted that a bou t 35% of the P inpu ts to natu ralw aters now com e from agricu ltu re in the U K, 70% in D enm ark, and 38% in Ge rm any. Since mo st so ils have a very h igh ab so rp t io n capacity fo r P, u sually far exceeding the quan t it ies of P added as m anu res o r fertilizers, it has long been con sidered that leach ing lo sses of P fromso il to w ater are negligib le in m o st case s. T he concen t r at i o n of P requ ired to t r igger eu t r op h icat i o n in fresh w ater is ex t r em ely s m all (as low as 0102～01035 m g P ƒL. T he p rob lem of P leach ing from so il to w ater w as generally no t con sidered i m po rtan t un t il the 1980s. W hen researchers first m easu red P lo sses in drainage w ater in the U K and U SA. It w as repo rtedthat P in drainage w ater cam e from fa r m yard m anu reapp lied to sandy so il. M o re recen t ly, repo rts abou t P leach ing from loam and clay so ils w ere pub lished. M o st researchers belive that the P in leach w ater is associated w ith the particu la te fract io n ( PP ). H ow eve r, H eck ra th and B rookes found that disso lved reactive pho spho ru s (DR P) , ranging betw een 66%基金项目: 教育部留学回国人员科研启动基金资助项目; 陕西省自然科学基金资助项目(2002D 09)收稿日期: 2002208223; 修订日期: 2003207210作者简介: 吕家珑(1962～) , 男, 甘肃民乐人, 博士, 教授, 主要从事土壤化学与环境化学教学和研究工作。

Foundation item: T he scientific research foundat ion fo r returned overseas Ch inese scho lars, State Educat ion M in istry and N atural Science Foundat ion of Shaanxi P rovince (N o. 2002D 09)Rece ived date: 2002208223; Accepted date: 2003207210Biography: LU J ia2L ong, Ph. D , p rofesso r, research invo lve in so il chem istry and environm ental chem istry.2690 生态学报23 卷and 86% of to tal P (T P ) , w as the largest fract io n in drainage w ater from B roadbalk. O ne po ssib le m echan ism invo lved in th is cou ld be p referen t ia l flow. M any facto rs, including clim ate facto rs, so il facto rs a nd hydro 2geo logic facto rs, im pact P leach ing. Scien t ists now w an t to p redict the t rend of P leach ing from s o il to w ater bodie s. Tw o k inds of m ethods are cu rren t ly u sed to p redict P leach ing. In one m ethod, p redict io n s are based on certain so il p ropertie s.Fo r examp le, B rookes et a l suggested that the rat io betw een CaC l2 2ex t ractab le P and O lsen2P , te rm ed“Change2po in t”,m igh t be a u sefu l p redicto r of the so il2 P concen t r at i o n s at w h ich there is sign if i can t risk of P movem en t from so il to w ate r. V an der Zee et a l u sed the pho sphate satu rat io n degree ( PSD ) to dete rm ine critical levels of P satu rat io n in so il in te rm s ofm ain tain ing accep tab le P concen t rat io n s in the groundw ate r. A no ther w ay to p redict P leach ing is to u se m athem atic models. M any models have been u sed. M eissner et a l developed a model2M OR PHO (M O delling of R eg io nal PHO spho ru s T ran spo rt ) to calcu la te flow and t ran spo rt p rocesses du ring re2 w etting. In it ia l modeling resu lts abou t the variat io n of sub su rface P 2leach ing lo sses fo r a selected site w ill b e p resen ted and conclu sio n s fo r the calcu la t i o n of re2w etting scenar io s, risk assessm en ts and fu tu re w o rk w ill be derived. In o rder to reduce P leach ing from agricu ltu ral system s, the overall goal shou ld be to b alance off2fa rm P inpu t in feed and fertilizer w ith ou tpu ts in harvested p roducts, w h ile m anaging so ils in w ays that m ain tain p roductivity. P ractical and innovative m easu res w ill be emp loyed fo r the con t r o l of a gricu ltu ral P 2leach ing to w ate r.Key words: agricu ltu ral so ils; pho spho ru s; leach ing; p redict i o n m ethod文章编号: 100020933 (2003) 1222689213 中图分类号: X53 文献标识码: A自20 世纪60 年代首次在美国和加拿大的大湖地区发现由磷素引起的水体富营养化现象以来, 人们惊讶地发现, 世界上许多地上(江、河、湖、水库等) 和地下水体都出现程度不同的磷素富营养化现象; 尤其是欧美发达国家, 这一现象更加普遍[ 1 ]。