An en­emy is turned back — with plants as weapons

Lo­cals join the sand fight in con­cert with na­ture and against it

China Daily (Hong Kong) - - ART - By YANG YANG

For sev­eral decades peo­ple who live along the Hexi Cor­ri­dor in north­ern China have fought to halt the desert as it spreads, and they have notched up sig­nif­i­cant vic­to­ries.

To the eye, the bar­ren land­scapes of loess plateau in the city of Lanzhou, Gansu prov­ince, were at once grand and heart rend­ing, with an end­less string of yel­low moun­tains that Mother Na­ture seems to have given up on. Long scars formed by wa­ter ero­sion run from the top of the moun­tains down through the sur­face, adding to the pic­ture of deso­la­tion.

In Yuzhong county of Lanzhou, the 300 mil­lime­ters of rain that fall each year washes loose earth down the moun­tains and into the Yel­low River in tor­rents that run through Lanzhou.

Yet lo­cals have man­aged to grow 253-sq km of cara­gana on the sunny and semi-sunny slopes of the loess moun­tains. The plants sur­vive eas­ily in the dry soil, with a life span of decades and some even pro­jected to live for more than 100 years. Car­gana’s roots run deep into the soil, as much as three me­ters, and helps to fix soil, pre­serve 34 per­cent of rain­fall and re­duce sur­face ero­sion by more than two thirds.

The con­trast be­tween these moun­tains — those cov­ered with flour­ish­ing plants and those cov­ered with un­sightly scars — is as clear as the dif­fer­ence be­tween life and death.

Gongjing Tree Farm in Yuzhong is lo­cated on a trib­u­tary 37 kilo­me­ters from the Yel­low River. It is one of the ma­jor sources of sed­i­ment in the river, whose tat­tered sur­round­ing land­form, loose soil and sparse veg­e­ta­tion cause se­vere wa­ter and soil loss.

Since 2013 lo­cal peo­ple have planted more than 3 mil­lion trees and dug 6 mil­lion holes to grow plant seeds. More than 75 per­cent of the seeds and their off­spring have sur­vived. Apart from shrubs such as cara­gana, they also grow Chi­nese thuja, Siberian apricot, Scots pine and elm — plants that can en­dure drought.

Over the same pe­riod, av­er­age an­nual rain­fall in the re­gion has risen from 280 mm to 330 mm.

Ef­forts by the lo­cals have not only helped im­prove the nat­u­ral en­vi­ron­ment, but have helped many make a liv­ing, for ex­am­ple by rais­ing chick­ens in the ar­eas where the trees they planted grow. From 2014 to 2017, 60 per­cent of a 20 mil­lion yuan ($3 mil- lion) govern­ment land care fund was paid in wages to lo­cals.

Sun­light and wa­ter

The city of Zhangye, 500 kilo­me­ters north­west of Lanzhou, is fa­mous for its nat­u­ral en­vi­ron­ment, and through it runs the sec­ond largest in­land wa­ter­way in China, the Heihe River. Flat land, fer­tile soil, ad­e­quate wa­ter and co­pi­ous sun­light have helped Zhangye be­come an im­por­tant food pro­duc­tion cen­ter for the coun­try. In an­cient times it was an im­por­tant mil­i­tary base on the Silk Road.

Yet, as for­tu­nate as Zhangye seems to be, it has not to­tally es­caped the mis­for­tunes of na­ture. Two thirds of one of its coun­ties, Linze, on the south­ern edge of Badain Jaran Desert, con­sists of desert, in­clud­ing semi-desert, and it faces a se­vere threat from de­ser­ti­fi­ca­tion.

Song En­tai, 54, chief en­gi­neer of the Linze Forestry Bu­reau, says that when he was a boy, se­vere sand­storms were a fre­quent oc­cur­rence.

“From March to May in the 1970s and the 80s when sand­storms came, you couldn’t see your hand in front of your face. We had this lit­tle verse: “When the wind blows, sand takes wing/ Bury­ing fields, houses and ev­ery­thing.” If farm­ers man­aged a har­vest of 200 kilo­grams a mu (667 sq m) that was a good year, but in the bad years they lost ev­ery­thing.

“We still have sand­storms, but there’s much less sand.”

In 1978, Linze county was listed as a key county for com­bat­ing de­ser­ti­fi­ca­tion as the Three-North For­est Shel­ter­belt De­vel­op­ment Pro­gram took ef­fect. Since then lo­cals have set up sand de­fenses that con­sist of check­box bar­ri­ers, grow­ing trees and shrubs in­side them. Plant­ing trees and shrubs is a top pri­or­ity for the lo­cal govern­ment ev­ery April.

From south to north, trees such as poplar have been planted, and mixed for­est zones have been planted, us­ing sac­saoul and rose wil­lows, and in the desert, shrubs that can bet­ter en­dure drought have been planted.

In the county’s south­ern and cen­tral ar­eas, plants have been put down to keep sand in check, and in the north for­est zones have been cre­ated that push seven kilo­me­ters into the Badain Jaran Desert.

The frost-free sea­son, which was an av­er­age of 152 days a year in the 1950s and 1960s, is 170 to 180 days a year now.

“That gives crops more time to grow, re­sult­ing in im­proved out­put,” Song says.

Farm­ers join bat­tle

Linze is noted for its qual­ity maze seeds and or­ganic red dates, and plant­ing in the name of fight­ing de­ser­ti­fi­ca­tion has in­creased lo­cals’ in­comes.

Other farm­ers in Gansu who have joined bat­tle against the spread­ing desert in­clude those of Min­qin county, in the city of Wuwei, who are also earn­ing money by grow­ing Chi­nese medicine based on sac­saoul. Nearly 89.8 per­cent of Min­qin’s 15,900-sq km land is de­ser­ti­fied, com­pared with 94.5 per­cent in 2009. The county has a pop­u­la­tion of 270,000.

Had de­ser­ti­fi­ca­tion gone unchecked, much more of the county would lie un­der sand be­cause at one stage the Teng­ger Desert and Badain Jaran Desert looked des­tined to meet, sand­storms lay­ing siege to many vil­lages be­tween March and May. In 2007 lo­cals of­fi­cially joined bat­tle against de­ser­ti­fi­ca­tion, and there is ev­i­dence to sug­gest that this work has paid off in re­duc­ing the sever­ity of sand-wind events.

“Peo­ple used to move the sand with carts,” says Cai Chengcheng, 31, deputy head of the county in charge of de­ser­ti­fi­ca­tion con­trol. “There was so much sand in the wind that af­ter a sand­storm, don­keys could climb onto the roofs of houses. The pop­u­la­tion kept fall­ing as more peo­ple moved away. Now they can sweep sand away much more eas­ily.”

To make sand fight­ing ef­forts more ef­fi­cient, the New En­ergy Tech­nol­ogy Co Ltd of Gansu Con­struc­tion and In­vest­ment Group Co­op­er­a­tion in Wuwei has de­vel­oped sand-sta­bi­liz­ing ma­chines to re­place hu­man la­bor, said to be the first of their kind in the world.

Ma­chines to the res­cue

Re­searchers first use drones to learn about a desert’s land­form in an ef­fort to work out the op­ti­mal point for mea­sur­ing wind speed and di­rec­tion, so as to de­ter­mine the re­quired size, height and di­rec­tion of check­box bar­ri­ers.

Then the sand-sta­bi­liz­ing ma­chines build bar­ri­ers ac­cord­ing to the re­quire­ments. The ma­chines are large con­verted trucks. Wo­ven straw is kept in the box of the truck.

Even­tu­ally, wind-break­ing seedlings are planted in the check­boxes.

In the tra­di­tional way, three or four peo­ple can build more than 600-sq m wo­ven straw check­box bar­ri­ers in a day, but a ma­chine op­er­ated by three peo­ple can build 40,000-sq m.

“This will help over­come the prob­lem of la­bor short­ages and ris­ing la­bor costs,” says Wang Chun­feng, deputy di­rec­tor of the In­ter­na­tional Depart­ment of the State Forestry Ad­min­is­tra­tion. “I hope this ex­pe­ri­ence can be used in de­ser­ti­fi­ca­tion con­trol in other coun­tries.”

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