the new jari - Philip M. Fearnside - Inpa

Long term viability offertilizing Jari's plantations, as in manyof the forms of high input agriculturearound the world, is clouded by thediminishing global store of inexpensivenutrients. Projections of world trendsindicate both potash and phosphate rockbeing exhausted by the year 2061 (UnitedStates, Council on Environmental Qualityand Department of State, 1980). 11Utilization of low grade deposits afterthis date would result in dramatic priceincreases, as well as requiring presentlyunachieved technological breakthroughs.In addition to the costof suppliyng nutrients to the plantations,with or without better recycling in thesystem, plantation area will have to in·crease to compensate for wood presentlyderived from native forest. Establishing,maintaining, and harvesting the 37.5%additional area for firewood will makesupplying energy a major figure in Jari'sbooks at some future date, although thecost would be reduced if the contemplatedhydroelectric dam at Cachoeira deSanto Antonio is built.The 15% of the presentGmelina-based pulp mix derived fromnative forest trees (Woessner, 1980a)will also have to be supplied fromplantations, raising costs accordingly.Prospects for Jari's silvicultureand pulp operation depend,in addition to establishing an equilibriumbetween nutrient inflows and outflowsin the system, on low risks of majoryield setbacks from pests, diseases, orother agronomic problems. Decline msoil nutrient levels can be expected toact synergistically with other factors tofurther jeopardize silvicultural yields.Less than optimal soil fertility for treegrowth, such as early Gmelina sites locatedon inappropriate soil types, increasesthe susceptibility of plantationsto insect pests (Johnson, 1977). Sitedeterioration through soil compaction andother processes expected to increase withfuture rotations will further exacerbatethis problem.The probability of significantlosses to insect and disease outbreakcan be expected to increase withincreasing area of monocultures planted,12and with the passage of time duringwhich pests and disease organisms notyet present can become established. 13Defoliation by pests can reduce plantationtree growth by varying amounts(Ribeiro and Woessner, 1980), adding tothe plantation area that would be neededto meet the pulp mill's demand for wood.In silvicultural operationsgenerally, many potential managementproblems are not solvable at acceptablecosts through traditional agri-cultural remedies such as chemical treatments.If a major disease problem arises,for example, the only option usually openis to switch to a new species unaffectedby the problem. Preparing the operationto counter such problems is difficult andcostly, but essential. Jari would be wiseto adopt as a goal the ability to sustainthe loss of one of its plantation species.Finding alternative speciesis not an easy process. The Eucalyptusdeglupta being planted on a commercialscale since 1979 had performedwell in young trial plots on some sitesprior to initiation of commercial planting,but only a few areas could be testedprior to adoption. E. deglupta is a speciesknown for more varied growth thanmost, with isolated trees or small plotscommonly doing much better than largecommercial stands (R. G. Lowe, personalcommunication, 1980). A nthrocephaluschinensis, a species which hasgiven excellent results in trials on someJ ari sites, has not been planted commerciallybecause it demands good soil, hasnarrower requirements for amount andtiming of water than other species, andis susceptible to a disease, not yet arrivedat Jari, which has attacked plantationsin Central America (C. Briscoe, personalcommunication, 1980, see Gibson andNylund, 1976).Pulpwood plantations,as in many forms of agriculture, are sustainedthrough a continued struggle of thehumans managing the system with biological,silvicultural, and technical problems.The relatively long cycle of thecrops, and the large investments involved,make it especially difficult tosteer a successful course where problemsmust be anticipated and corrective actiontaken several years before yield declinesbecome economically significant. To acertain extent the sustainability of thesystem depends on high quality researchand monitoring efforts.The relative prices ofpulp as compared with needed inputs willbe crucial in determining whether stepsare taken by management to increasethe likelihood of long term production.Pulp prices can be expected to rise asworld consumption of white chemicalpulps continues to increase from 43 . 8million metric tons per year in the 1972-73 period to a projected 67.1 millionmetric tons per year in 1990 (UnitedNations, F.A.O., 1977: 144). Whetherrising prices of inputs will cancel thesegains is unknown: commodity prices are,unfortunately, more responsive to supplyand demand at any given time than tothe cost of investments needed to sustainproduction at some future date.Political and bureaucraticdecisions affecting the silviculturaloperation may have at least as muchimpact on its ultimate sustainability asthe many biological and agronomicthreats to continued production. Regu·lations regarding marketing and pricingare particularly important, 14 amongmany other factors.Irrigated RiceThe irrigated rice projectin diked varzea (floodplain) at SaoRaimundo has recently undergone set.backs, both agronomic and economic,leading to management changes andclose scrutiny of the project. One majorcause of worry was a sharp fall in riceyields in 1979 to about 7 metric tons/ha/ year from slighty over 8 metrictons/ ha/ year in the previous year.Various contributing causes have beenidentified, and some have been remediedthrough management changes.One reason for the decline was iron toxicity,evinced by accumulation of brownsludge on the rice roots. Although thearea's soils are prone to this problem,iron toxicity can be minimized throughcareful water management in the paddies.A delicate balance exists between excessiveflooding, leading to iron toxicity,and dryness, leading to aluminum toxicity.A preflood helps raise pH levelsand reduce iron toxicity.Increased insect attacksare believed by the technical staff to bea major factor affecting rice yidds. Armyworms (Spodoptera frugiperda) are aparticularly persistent problem, which canquickly inflict severe losses if timelyand effective controls are not taken eachtime populations begin to increase. Thearmy worm problem, like the toxicityproblems, is linked to water manage·ment: flooding the paddies when theworms are young being an importantweapon in the battle to control thesepests (see Grist, 1975: 320).Stink bugs (Oebaluspoecilus) have also been a problembelieved to contribute to yield declines.Attacks of these insects on rice rootsN\1ERCIEI\[IR NOV- DEC 1982, VOL. 7 N9 6333