Vol. 51—1997 - NorthEastern Weed Science Society
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Vol. 51—1997 - NorthEastern Weed Science Society

Vol. 51—1997 - NorthEastern Weed Science Society Vol. 51—1997 - NorthEastern Weed Science Society

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Waggone December 24, 1994 134 25 Pasco 1992 ~ 20 • tQ ~ :s ·iii ::5: 15 10 5 0 194 1960 1980 2000 2020 2040 2060 Fig 4. The 1940 and a ceiling of grown by t Growers As I say lift not rise b fact, the that preva lift the c continuall and suppli fall, and course of average maize yields in the U.S. since logistic curve rising at 3.6% per year toward a 21 t/ha. The yield labeled Pasco is the 21 t/ha e winner of a national contest. (National Corn ociation 1993 and USDA statistics various ears.) rather than rising yields to emphasize yields do themselves. Someone must do heavy lifting. In igher farmers lift yields above the 1 to 2 t/ha led for centuries, the more holding up needed. To rve, sparing land for Nature, scientists must discover, governments set incentives, and farmers rs venture. Otherwise yields will stagnate or efferson's Imperative will take land from Nature. I have def nded my third resolution: Yield can be lifted more, whi Jefferson's Imperati ve shows spares more land for Nature. Environmen Jefferson given popu yields can worriers' lifting yi expense of sparing land an convince worriers about Nature that, for a ation and consumption per capita, only higher spare land for Nature. Contest winners can stir opes that winning yields keep head room open for Ids.

Waggoner December 24, 1994 135 But, the wor iers still fear that the environmental expense of intensifi ation to lift yields will fallout onto the very land spared or Nature. So, in the e d I must defend: Environmental expense need not cancel the p of it of sparing land for Nature. Economists would call e vironmental expense 'externalities', environmenta ists would call it 'impact' and laymen would call it 'pol ution'. In other places I have called it 'fallout' bu here use the analogy of expense. (Hereafter I often abbrev'ate 'environmental expense' to simple 'expense'). complete reckoning must subtract this expense before reach'ng the bottom line of a profit of land spared for Nature. s .sing bonuses After buying a computer to save clerical labor, the boss of Widgets Inc. might be surprised by a bonus of accurate addition of ustomer's bills. Just so, more tons per hectare can grant en ironmental bonuses, which should be enumerated before tally'ng the expenses of lifting yields. Farmers do s actually inc appear on al and cultivat land from th erosion and Irrigation, plus its inf salinity, al Lining ditch crop harvest higher yield radiation mo of foliage t So the canop humanity has yields less. me things per area, and higher yields may r less expense than low yields. Erosion and silt lists of expenses. A farmer must clear, till, for low as well as high yields. So by sparing plow, higher yields give a bonus of less ilt. ts consumption of water from streams or aquifers astructure of dams and canals plus fallout of o appears on lists of environmental expenses. s and trickle irrigation raise the efficiency of d per water used. Although often overlooked, also raise efficiency. Because incoming e or less sets evapotranspiration, all canopies at shade the ground consume about equal water. that photosynthesizes more and yields more for a higher water use efficiency than one that Lush foliage needs little more pesticide to protect it from an insect or a disease than does sparse foliage. Keeping weed a bumper era keeping them More than a fundamental that, while shading and showed, "Whe increasingly from the shade beneath the luxuriant foliage of actually may require less herbicide than from the thin shade beneath the sparse foliage. core of years ago, Knake (1972) demonstrated the atter, shade stunts foxtail. Now, Fig 5 shows ielding more, denser maize delivers a bonus of eakening weeds. And, Valenti and Wicks (1992) nitrogen was applied, winter wheat became vigorous, [andJ increased light interception

Waggone December 24, 1994<br />

134<br />

25<br />

Pasco 1992 ~<br />

20 •<br />

tQ<br />

~<br />

:s<br />

·iii<br />

::5:<br />

15<br />

10<br />

5<br />

0<br />

194 1960 1980 2000 2020 2040 2060<br />

Fig 4. The<br />

1940 and a<br />

ceiling of<br />

grown by t<br />

Growers As<br />

I say lift<br />

not rise b<br />

fact, the<br />

that preva<br />

lift the c<br />

continuall<br />

and suppli<br />

fall, and<br />

course of average maize yields in the U.S. since<br />

logistic curve rising at 3.6% per year toward a<br />

21 t/ha. The yield labeled Pasco is the 21 t/ha<br />

e winner of a national contest. (National Corn<br />

ociation 1993 and USDA statistics various ears.)<br />

rather than rising yields to emphasize yields do<br />

themselves. Someone must do heavy lifting. In<br />

igher farmers lift yields above the 1 to 2 t/ha<br />

led for centuries, the more holding up needed. To<br />

rve, sparing land for Nature, scientists must<br />

discover, governments set incentives, and farmers<br />

rs venture. Otherwise yields will stagnate or<br />

efferson's Imperative will take land from Nature.<br />

I have def nded my third resolution: Yield can be lifted<br />

more, whi Jefferson's Imperati ve shows spares more land for<br />

Nature.<br />

Environmen<br />

Jefferson<br />

given popu<br />

yields can<br />

worriers'<br />

lifting yi<br />

expense of sparing land<br />

an convince worriers about Nature that, for a<br />

ation and consumption per capita, only higher<br />

spare land for Nature. Contest winners can stir<br />

opes that winning yields keep head room open for<br />

Ids.

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