locus, regenerating a 10-kb Sal I fragmentof the CHLI gene, the same size found inwild-type plants (Fig. 3A). Sequence anal-ysis of the CHL1 gene in four of therevertants verified that the element hadexcised, leaving behind a small insertion(Fig. 2). In addition, new restriction frag-ments that hybridized with radiolabeledTagl sequences were evident in the rever-tants (Fig. 3B). Thus, in the revertants,Tagl or Tag) -related elements had insertedinto new loci. We conclude that Tagl is amobile transposable element.

To confirm that Tagl is an endogenouselement of Arabidopsis, genomic DNA wasisolated from the untransformed parentused to construct the transgenic Ac lines.The parent originated from the ecotypeLandsberg and carries the morphologicalmutation erecta. Southern blot analysiswith radiolabeled Tagl DNA indicated thatthe Landsberg erecta parent contains Tagland two additional Tagl-related elements,each present in only one copy per haploidgenome (Fig. 4). No Tagl or related se-quences were found in two other ecotypesof Arabidopsis, Columbia and Wassilewskija(Fig. 4).

By selecting for chlorate-resistant mu-tants of Arabidopsis from a population car-rying an active Ac element, we havetrapped a new mobile Arabidopsis transpo-son. Tagl transposition may have beenstimulated in the Landsberg plants by theDNA breakage or genomic stress caused bythe integration of T-DNA into the Arabi-dopsis genome, by the transposition of Ac(13), or by the propagation of the plantcells in tissue culture (14). Upon activa-tion, the element transposed to the chlllocus and, when homozygous, producedchll mutant progeny. We think it unlikelythat the Ac transposase directly mobilizesTagl, as no Ac transposase binding site(AAACGG) is found adjacent to the in-verted repeats of Tagl as it is in Ac (15).Whatever the mechanism of activation, thenow mobile Tag) should be useful for tag-ging plant genes.

REFERENCES AND NOTES1. B. McClintock, Science 226, 792 (1984); 0. Nel-

son, Ed., Plant Transposable Elements (Plenum,New York, 1988); V. Walbot, Annu. Rev. PlantPhysiol. Plant Mol. Biol. 43, 49 (1992); D. E. Bergand M. M. Howe, Eds., Mobile DNA (AmericanSociety of Microbiology, Washington, DC, 1989).

2. E. M. Meyerowitz, Ce1/56, 263 (1989); R. Shields,Nature 337, 308 (1989).

3. K. A. Feldmann, M. D. Marks, M. L. Christianson,R. S. Quatrano, Science 243, 1351 (1989); M. D.Marks and K. A. Feldmann, Plant Cell 1, 1043(1989); C. Koncz et al., EMBO J. 9, 1337 (1990);M. F. Yanofsky, H. Ma, J. L. Bowman, G. N.Drews, E. M. Meyerowitz, Nature 346, 35 (1990);K. A. Feldmann, Plant J. 1, 1 (1991).

4. V. Arondel et al., Science 258, 1353 (1992).5. D. F. Voytas and F. M. Ausubel, Nature 336, 242(1988); D. F. Voytas, A. Konieczny, M. P. Cum-

mings, F. M. Ausubel, Genetics 126, 713 (1990);A. Konieczny, D. F. Voytas, M. P. Cummings, F. M.Ausubel, ibid. 127, 801 (1991).

6. J. Peleman, B. Cottyn, W. V. Camp, M. V. Mon-tagu, D. Inze, Proc. Natl. Acad. Sci. U.S.A. 88,3618 (1991).

7. M. A. Van Sluys, J. Tempe, N. Federoff, EMBO J.6, 3881 (1987); R. Schmidt and L. Wilmitzer, Mol.Gen. Genet. 220,17(1989); C. Dean, C. Sjodin, T.Page, J. Jones, C. Lister, Plant J. 2, 69 (1992); J.Swinburne, L Balcells, S. R. Scofield, J. D. G.Jones, G. Coupland, Plant Cell 4, 583 (1992); C.Grevelding etal., Proc. Natl. Acad. Sci. U.S.A. 89,6085 (1992).

8. B. Aberg, Ann. R. Agric. Coil. Swed. 15, 37(1947).9. F. J. Braaksma and W. J. Feenstra, Theor. Appl.

Genet. 64, 83 (1982); M. Caboche and P. Rouze,Trends Genet. 6, 187 (1990); J. L. Wray and J. R.Kinghorn, Eds., Molecular and Genetic Aspects ofNitrate Assimilation (Oxford Univ. Press, Oxford,1989); N. M. Crawford, in Genetic Engineering:Principles and Methods, J. K. Setlow, Ed. (Ple-num, New York, 1992), pp. 89-98.

10. H. Doddema, J. J. Hofstra, W. J. Feenstra, Phys-

11.

12.

13.14.

15.

16.

17.

iol. Plant. 43, 343 (1978); H. Doddema and G. P.Telkamp, ibid. 45, 332 (1979); H. J. Scholten andW. J. Feenstra, ibid. 66, 265 (1986).C. Dean, C. Sjodin, T. Page, J. Jones, C. Lister,Plant J. 2, 69 (1992).Y.-F. Tsay, J. I. Schroeder, K. A. Feldmann, N. M.Crawford, Cell 72, 705 (1993).B. McClintock, in (1).V. M. Peschke, R. L. Phillips, B. G. Gengenbach,Science 238, 804 (1987).R. Kunze and P. Starlinger, EMBO J. 8, 3177(1989); S. Feldmar and R. Kunze, ibid. 10, 4003(1991).J. Wilkinson and N. Crawford, Plant Cell 3, 461(1991).We thank E. Johnson and K. Long for technicalhelp and R. Schmidt and M. Yanofsky for discus-sion. Supported by the Powell Foundation and theNational Institutes of Health (GM 40672 to N.M.C.and 5T32CA09345-12 for M.J.F.) and the AFRCPMB Programme to C.D. This paper is dedicatedto the memory of Barbara McClintock (1902-1992).5 November 1992; accepted 22 February 1993

Soil Quality and Financial Performance ofBiodynamic and Conventional Farms in New Zealand

John P. Reganold,* Alan S. Palmer, James C. Lockhart,A. Neil Macgregor

Biodynamic farming practices and systems show promise in mitigating some of the det-rimental effects of chemical-dependent, conventional agriculture on the environment. Thephysical, biological, and chemical soil properties and economic profitability of adjacent,commercial biodynamic and conventional farms (16 total) in New Zealand were compared.The biodynamic farms in the study had better soil quality than the neighboring conventionalfarms and were just as financially viable on a per hectare basis.

Concerns about environmental, econom-ic, and social impacts of chemical or con-ventional agriculture have led many farmersand consumers to seek alternative practicesthat will make agriculture more sustainable.Both organic and biodynamic farmers useno synthetic chemical fertilizers or pesti-cides, use compost additions and manuresto improve soil quality, control pests natu-rally, rotate crops, and diversify crops andlivestock. Unlike organic farmers, biody-namic farmers add eight specific prepara-tions, made from cow manure, silica, andvarious plants, to enhance soil quality andplant life (1).We examined soil properties and finan-

cial performance on pairs or sets of biody-namic and conventional systems over a4-year period (1987 to 1991) on the NorthIsland of New Zealand (Table 1). We alsoJ. P. Reganold, Department of Crop and Soil Sciences,Washington State University, Pullman, WA 99164.A. S. Palmer and A. N. Macgregor, Department of SoilScience, Massey University, Palmerston North, NewZealand.J. C. Lockhart, Department of Agricultural and Horti-cultural Systems Management, Massey University,Palmerston North, New Zealand.*To whom correspondence should be addressed.

made financial comparisons between thesefarms and representative conventionalfarms in each study region on the basis ofmodels used by the New Zealand Ministryof Agriculture and Fisheries (MAF) (2). Afarm pair consisted of two side-by-sidefarms, one biodynamic and one conven-tional; a farm set consisted of three adjacentfarms, one biodynamic and two conven-tional. The choice of five farm pairs andtwo farm sets (totaling 16 farms) was madeon the basis of surveys, interviews, andon-farm soil examinations of more than 60farms to ensure that all soil-forming factors,except management (3), were the same ineach farm pair or set.

The biodynamic farms had been man-aged biodynamically for at least 8 years,with the oldest for 18 years, to provide timefor the biodynamic farming practices toinfluence soil properties. The farm pairs orsets included a range of representative farm-ing enterprises in New Zealand: marketgarden (vegetables), pip fruit (apples andpears), citrus, grain, livestock (sheep andbeef), and dairy. Farms in each pair or sethad the same crop and livestock enterprise.Paddocks (fields) chosen for study in each

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farm pair or set had soils in a single soilprofile class and were located at the junc-ture of adjoining farms. The soil of eachpaddock was sampled at numerous locations(4). In total, 130 soil samples from 22paddocks were taken and analyzed (5).

In six of the seven farm sets (Table 2),the biodynamically farmed soils had betterstructure and broke down more readily to agood seedbed than did the conventionallyfarmed soils. The crumb and nut structuresfound predominantly on the biodynamicfarms provide better aeration and drainagefor crop or grass growth compared with theblocky and clod structures found mostly onthe conventional farms (6). Soil was morefriable, which makes it more easily tilled by

farm machinery, on four of the seven bio-dynamic farms compared with that of theirconventional neighbors.

The surface soil bulk density was signif-icantly less on four of the biodynamic farmsthan on their conventional counterparts(Table 2); when all data were aggregated,bulk density was significantly lower on thebiodynamic farms (Table 3). Bulk density isrelated to mechanical impedance and soilstructure, both of which affect root growth.Penetration or cone resistance is anotherindicator of mechanical impedance. Two ofthe three biodynamic farms in pasture hadsignificantly lower penetration resistancesin the upper 20 cm than their conventionalcounterparts had. The results were variable

for the horticultural and mixed farms (Ta-ble 2). Overall (Table 3), the biodynamicfarms had a significantly lower penetrationresistance in the upper 20 cm; there was nodifference between farming systems in soil20 to 40 cm below the surface.

Organic matter content, soil respiration,mineralizable nitrogen, and the ratio ofmineralizable nitrogen to organic carbonwere significantly higher on almost all thebiodynamically farmed soils than on theconventionally farmed soils (Table 2). Theaggregated data (Table 3) indicate signifi-cantly higher values for these four parame-ters on the biodynamic farms. The higheramounts of organic matter on the biody-namic farms have contributed to better soil

Table 1. General farm characteristics. Abbreviations: bio, biodynamic; veg, vegetables; con, conventional; pip, pip fruit; cit, citrus; and org, organic.

Number Farm Pad-Farm Main of years size docks* Fertilizerst Pesticides and pestenterprise (1966 to (ha) per (1983 to 1991) management (1983 to 1991)

1991) farmBio veg Market 13 con; 1 1 1 Manures, composts, Cultural controls,* biological

garden 4 org; bonemeal, fishwastes, controls, copper and sulfur spraysil8 bio biodynamic preparations

Con veg Market 25 con 45 1 12-5-14 and 12-10-10 of Propyzamide, alachlor, maneb, propineb,garden N-P-K vinclozolin, methamidophos

Bio pip Pip fruit 10 con; 5 2 Composts, fish manures, Cultural controlst15 bio biodynamic preparations

Con pip 1 Pip fruit 25 con 7 1 12-10-10 of N-P-K, Terbacil, simazine, glyphosate,potassium chloropyrifos, guthion, azocyclotin,superphosphate polyram, captan, triadimefon,

dodine, bitertanolCon pip 2 Pip fruit 25 con 24 1 12-10-10 of N-P-K Amitrole, simazine, terbacil, glyphosate,

guthion, azocyclotin, chloropyrifos,polyram, captan, dodine, bitertanol,myclobutanil, fruit-fed ANA

Bio cit Citrus 17 con; 10 3 Composts, fish fertilizer, Copper sprayll biological controls8 bio biodynamic preparations

Con cit 1 Citrus 25 con 12 2 Nitraphoska (N-P-K Glyphosate, paraquat, acephate,fertilizer), urea, copper oxychloridesuperphosphate with traceelements

Con cit 2 Citrus 25 con 9 1 Urea, superphosphate, Glyphosate, terbuthylazinefertigation with ammonium plus terbumeton, dimethoate,nitrate, calcium nitrate, clofentezine, thiazolidone, diazinon,sulfate of potash copper oxychloride, maneb plus

zinc and manganese, benomylBio mixed Grain, sheep, 15 con; 202 1 Rock phosphate, seaweed, Cultural controls,f biological controls

and beef 10 bio composts, biodynamicpreparations

Con mixed Grain, sheep, 25 con 280 1 Superphosphate, urea, MCPA + triazine, MCPB 2,4-D,and beef chlormequat chloride chlorsulfuron, pirimicarb,

terbuconazole, cultural controls*Bio livestock Sheep and 12 con; 180 1 Fish fertilizer, biodynamic Cultural controls,f biological controls

beef 13 bio preparationsCon livestock Sheep and 25 con 445 1 Fish fertilizer, rock MCPA, glyphosate, picloram,

beef phosphate, chicken dimethyl carbatemanure

Bio dairy 1 Dairy 1 con; 6 org; 25 1 Rock phosphate, seaweed, Cultural controls,f biological controls18 bio fish fertilizer,

biodynamic preparationsCon dairy 1 Dairy 25 con 51 1 Potassium superphosphate MCPABio dairy 2 Dairy 15 con; 235 2 Biodynamic preparations Cultural controls,* biological controls

10 bioCon dairy 2 Dairy 25 con 150 2 15-10-10-8 of N-P-K-S, urea 2,4-D*Number of paddocks or fields where soil was sampled on a particular farm. tIncludes organic and synthetic chemical fertilizers. *Cultural pest controls includephysical and mechanical practices such as rotating and diversifying crops, green manuring, clearing weeds from field borders, and altering the timing or way ofplanting. Biological pest controls involve the introduction or buildup of natural predators, parasites, and pathogens that keep pest populations below injuriousnumbers. BApproved chemical spray by the New Zealand biodynamic and organic certification boards. A plant growth regulator.

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Table 3. Mean values of aggData were analyzed with Avariation due to different efwas absorbed or removed (

Soil property

Bulk density (Mg m-3)Penetration resistance

(0 to 20 cm) (MPa)Penetration resistance

(20 to 40 cm) (MPa)Carbon (%)Respiration (p1 02

hour-1 g-1)Mineralizable N(mg kg-1)

Ratio of mineralizableN to C (mg g-1)

Topsoil thickness (cm)tCEC (cmol kg-1)!:Total N (mg kg-1)Total P (mg kg-1)Extractable P(mg kg-1)

Extractable S(mg kg-1)

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(cmol kg-1)pH*P < 0.01. tTopsoil thicknEand subsurface (A) horizons.capacity in centimoles of cationgram of soil. Centimole ch