Relation of frosts and air drainage to fruit growing

              NE'',II MUUC0 COI"LECA 0F ;IGRICIItTURE AND iIECHANIC ARTS
Al'lD AGRICUTTURAL EXPEhIMF IT STATION
Press Bulletln 101
RELITION 0F FIiOSTS AI{D AIR DRAINAGE T0 FRUIT GfiOTIING
The subject of the late spring frosts is one of great irqportance to the
fnrit grower; and one that desen/es nore consideration than it generally gets'
The llght spring frosts frequently cause great losEes to the fruit grower, and
this dangerseems to increaee rvith certain varieties in the South and Southwest.
Thls fact hes been qutte well demonstrated ln New Mexico. Many fruits which
succeed in the tlorth and East are practically vrorthless on eccount of their
liability to fr"ost lnjury during the spring. The orchard fnri-ts that suffer the
most are the Japanese plrrns, Iate rtpening peaches, ffid apricots.
The damaging effects oi these light frosts cone when the trees ere elther
in bloorn or just as the tender fruit is forming. At this stage of the treers
g- ro'oth, a very Ught frost urill be enough to destroy the cr-op, Tlhile thLre ire a nrunber of ways by means of which this danger nay be nitl-gated,
that of air drainage is as practical ancl as iiryottant as any. Frequently,
i plantation vrith good air drainage escapes frost injury r'ften the adjacent or-chirds
in the }ower lands arr: killed. The air is raiely perfectly stillr and
yet there are nights when it appears to be so. The danger increases during stlll
and. cloudless nights, parblcularly in the spring rfiile the trees are jn bloom
an4 vrhen radiatlon is lrost rapid. Cold air is he.qvier and denser and, accord-ingly,
lt w:il} settle in the low places and valleys. At night, the cold air
vAff- descend fron the hills and elevated regions into the valleys and dlsplace
the warmer air, which rrill rise. Jr person, in going across a val'ley in the-spring,
in the-evening, will notlce the cooler air in the depressions and. old
riverUeds, ff the night is clear and there is no vrj-nd to keep the air in
motion, this heavier and cold air rTil1 lie in the lolv places and_frequenlly
cause enough frost to inJure tender vegetation or newly forrdng fnritr when
sigilar growttr may escape inJury Just a few feet hi.gher. This drairtage of the
cold air-to the depressions ie the secret of nnrch of the success of fnrit
gro'orlng on high anci sloping lands. And, for this reasonr it becomes very
inrportant to give mrch attention to the selection of the site for tender fntj.ts.
nAi a rule, the ideal site for a fruit plantation is one which is sonelvhat
elevated above the adjoini-ng lands.tt The elevation need not be very great.
A conparatively slight elevation usually gives good air dreinage, particularly
so !f tfre lana has a-slope so that the air rnay gradually drain anray. Farm^s j.n
the large valleys rnay be srrfficlently elevated above the general level of the
valley or the local riverbeds and other depressions to anslver the purpose for
fnrit sites, Of eourse, nore pronorutced elevatj.onsr [P to a certai.n lirait,
gjve better results.
Frequently, the valleys arc lower elong the edges, next_to the foothllls,
than towad the niddle, and the air draining frorn the foothills will settle in
the lowest places and there cause the rnost serlous danage to frults. The sloping
focthills make ldea1 sltes, especirlly for the more tender fruits. The planting of
tender fnrits in the valleys next to the foothills, vshcn the va1ley has a gradual
elevation to the nictdler is not always a sofe practice, Uncler such conditionse bet-ter
fnrit sites can be for.urd to the niddle of the valley'
The present orcharC at the &cperinent Statlon Ls located about one fourth of
a rrj.le fron the foothills and the valley at this place is lovrer than to'rard the
nriddle. On several occasions it has been obsenred that varieties of peaches and
other tender fmits have been destroyed by the light spring frosts, ivhile the sane
varieties in orahards into the midctle of the valley produced good crops. Last
spring the freeze of April lL praetically destroyed al*l the fntlt at the Station
orchard. and the new grovlth of S or 10 inches on the grapes, vrhile the orchards and
vineyards locsted from one to 3 miles to the nlddle of the valley were not very
seriously danagecl..
Feb, 2L, 1905 Fabirm Garcia