Hendrik J. Bruins

Rainwater-harvesting agriculture for food production in arid zones: the challenge of the African famine

Abstract Rainwater-harvesting agriculture is a specialized form of rainfed farming that has a significant potential to increase food production in the arid zones of our planet. Runoff farming and rainwater-harvesting agriculture are considered synonymous terms, defined here as ‘farming in dry regions by means of runoff rainwater from whatever type of catchment or ephemeral stream’. There are indications that runoff rainwater was already used for farming during the Neolithic. Remnants of ancient rainwater-harvesting agricultural systems have been found in many dry regions of Asia, Africa and America. Today, rain is still the cheapest and often only available source of water for agricultural purposes, albeit not always reliable. In many dry regions of the world there is no alternative but a better and more effective use of rain to increase food production. This is the essence and potential significance of runoff farming in a hungry world. A geomorphic classification of runoff farming systems is presented, as suitability of an arid region for rainwater-harvesting agriculture depends upon the landscape as much as upon the climate. Hyper-arid zones are usually too dry for runoff farming. Five major types of runoff farming are distinguished, arranged in order of generally increasing geomorphic scale: (1) micro-catchment system, (2) terraced wadi system, (3) hillside conduit system, (4) liman system, (5) diversion system. The introduction and use of runoff farming in arid zones of a number of African countries is reported. As arid regions are characterized by large yearly fluctuations in the amount of runoff-producing rainfall, droughts have to be taken into account in proper runoff farming management. The forming of reserve buffer stockpiles of water and food during the good years for drought periods are considered essential in this respect.

Special climatological conditions in the deserts of Sinai and the Negev during the latest Pleistocene

Abstract Results of hydrological and geological investigations carried out during the last ten years in the deserts of the Sinai and the Negev indicate that unique climatological and hydrological conditions prevailed between ca. 100,000 and ca. 10,000 yr B.P. The uniqueness was expressed by the following characteristics: 1. (1) Higher precipitation and recharge rates caused the Nubian Sandstone aquifers to be filled up through the outcrops in central Sinai and to overflow through big springs emerging along the faults of the Syrian—African rift system. This water is of special isotopic composition, namely depleted in 18O and deuterium and with a lower excess of the latter. 2. (2) Dust-laden rainstorms prevailed, probably mainly during the autumn season, causing the deposition of thick layers of loess. The quantity of rain during the humid periods was double that of the present. 3. (3) The drainage system of many western and northern wadis of Sinai as well as the Negev could not drain out all the silt-loaded water during the rainy season, and shallow lakes and marshes extended in many wadis during this season. 4. (4) The floods and the springs flowing into the Dead Sea rift valley contributed to the Lisan Lake, which was 200 m above the level of the contemporary Dead Sea.

Radiocarbon dating in near-Eastern contexts: Confusion and quality control

Near-Eastern archaeology has long remained oblivious to radiocarbon dating as unique historical calendars brought about a perception that 14 C dating is superfluous. Circular chronological reasoning may occur as a result. There is now strong 14 C evidence that the early part of Egyptian history seems older than age assessments currently in vogue among scholars. It is vital to apply systematic and high-quality 14 C dating to each and every excavation in the Near East to measure time with the same yardstick. Such a strategy will enable chronological comparison of different areas at an excavation site and also between sites and regions, independent of cultural deliberations. This is essential for proper interpretation of archaeological layers and association with data from other fields. Radiocarbon ( 14 C) is the most common radiometric dating tool applied in archaeology, geosciences, and environmental research. Stringent quality control is required to build up a reliable 14 C chronology for the historical periods in Near-Eastern contexts. Important aspects of quality control involve regular laboratory intercomparisons, transparent duplicate and triplicate analysis of selected samples, conventional versus accelerator mass spectrometry (AMS) (i.e. sample size), sample selection and association. Finally, bones may provide short-lived dates in important stratigraphic archaeological contexts.

Residual colluvio-aeolian aprons in the Negev highlands (Israel) as palaeo-climatic indicator

Abstract Slope features, treated previously mainly pedogenetically and described as alluvial terraces or as a catenary compound of stony loessial Sierozem, are shown to be remains of former colluvial-loessial aprons. The loess was deposited in the central Negev during the uppermost Pleistocene by dust-laden rainstorms which triggered debris flows under conditions twice as humid as today. During the Holocene the aprons were selectively eroded by slope-runoff, resulting in a wide exposure of the basal slope, truncation of the wadi fill and the final formation of the present-day patchy slope morphology. The dust-laden rainy regime fits the last, more humid period, i.e. 70,000–10,000 yr B.P.

Proactive Contingency Planning vis-a` -vis Declining Water Security in the 21st Century

This article examines the theoretical and practical risks to water security, which is rapidly declining in many parts of the world, particularly in drylands. Water security is threatened by current land-use developments and over-utilization of groundwater. About 70 per cent of freshwater resources is globally used by irrigation agriculture. Interrelated water and food shortages may occur in the 21st century as the predictable outcome of current developments. This may lead to regional famine and political instability. Unpredictable contingencies, such as drought, earthquakes, terrorism, conflict and war, can also affect water security in a negative and dangerous way. Predictable and unpredictable, adverse developments vis-a-vis water security require more theoretical and practical studies. The important linkage between contingency planning and crisis management has to be developed and refined, including terminology. Safe underground water resources must be identified and developed in every nation and province as strategic reserves in civil emergency planning.

THE NEED FOR A CALIBRATED RADIOCARBON CHRONOLOGY OF NEAR-EASTERN ARCHAEOLOGY

Progress in radiocarbon dating and calibration accuracy should lead to the development of a calibrated radiocarbon chronology of Near Eastern archaeology, particulary for historical times. The lack of such an independent and impartial chronology is a major constraint, not only in archaeological studies, but also for interdisciplinary research involving the history of man, landscape and climate in the Near East and adjacent regions.

RADIOCARBON DATING THE WILDERNESS OF ZIN

An important archaeological survey was conducted by Leonard Woolley and T E Lawrence in 1914 on behalf of the Palestine Exploration Fund in the Negev and northeastern Sinai desertsthe Wilderness of Zin. The region of Ain Kadeis, associated by some scholars in the 19th century with biblical Kadesh-Barnea, received much attention in their survey and discussions. Concerning the vexed question of Kadesh-Barnea, Woolley and Lawrence gave their preference for the nearby Ain el Qudeirat1 Valley, and in particular the ancient tell. Their survey contributed significantly in the shaping of scholarly opinion on the matter, even until today. But modern surveys and excavations failed to identify any archaeological remnants of the 2nd millennium BCE in the above regions, thereby putting the above associations in question. The Middle Bronze Age II, Late Bronze Age, and Iron Age I that cover this millennium are considered missing in the area in archaeological terms. However, our research reveals that archaeological remains of the 2nd millennium BCE do exist in the region, as determined chronologically by radiocarbon dating. A geoarchaeological approach is required to investigate terraced fields in wadis, which contain a unique record of human activity in these desert regions.

The Minoan Santorini Eruption and Tsunami Deposits in Palaikastro (Crete): Dating by Geology, Archaeology, 14C, and Egyptian Chronology

Deposits from the Minoan Santorini (Thera) eruption in the eastern Mediterranean region constitute the most important regional stratigraphic marker in the chronological perplexity of the 2nd millennium BCE. Extensive tsunami deposits were discovered in Crete at the Minoan archaeological site of Palaikastro, containing reworked volcanic Santorini ash. Hence, airborne deposition of volcanic ash, probably during the 1st (Plinian) eruption phase, preceded the tsunami, which was apparently generated during the 3rd or 4th phase of the eruption, based on evidence from Thera. Average radiocarbon dates (uncalibrated) of animal bones in the Palaikastro tsunami deposits along the coast (3350 ± 25 BP) and at the inland archaeological site (3352 ± 23 BP) are astoundingly similar to the average 14C date for the Minoan Santorini eruption at Akrotiri on Thera (3350 ± 10 BP). The wiggle-matched 14C date of the eruption in calendar years is 1627-1600 cal BCE. Late Minoan IA pottery is the youngest element in the Palaikastro tsunami deposits, fitting with the LM IA archaeological date for the Santorini eruption, conventionally linked at ~1500 BCE with Dynasty XVIII of the historical Egyptian chronology. The reasons for the discrepancy of 100?150 yr between 14C dating and Egyptian chronology for part of the 2nd millennium BCE are unknown. 14C dates from Tell el-Dabca in the eastern Nile Delta show that the 14C age of the Santorini eruption matches with 14C results from 18th Dynasty strata C3 and C2, thereby confirming grosso modo the conventional archaeo-historical correlations between the Aegean and Egypt. We propose that a dual dating system is used in parallel: (1) archaeological material-cultural correlations linked to Egyptian chronology; (2) 14C dating. Mixing of dates from the 2 systems may lead to erroneous archaeological and historical correlations. A ?calibration curve? should be established between Egyptian chronology and 14C dating for the 2nd millennium BCE, which may also assist to resolve the cause of the discrepancy.

Tell es-Sultan (Jericho): Radiocarbon results of short-lived cereal and multiyear charcoal samples from the end of the Middle Bronze Age

Samples from Tell es-Sultan, Jericho, were selected for high-precision 14C dating as a contribution toward the establishment of an independent radiocarbon chronology of Near Eastern archaeology. The material derives from archaeological excavations conducted by K. M. Kenyon in the 1950s. We present here the results of 18 samples, associated stratigraphically with the end of the Middle Bronze Age (MBA) at Tell es-Sultan. Six short-lived samples consist of charred cereal grains and 12 multiyear samples are composed of charcoal. The weighted average 14C date of the short-lived grains is 3306 ± 7 BP. The multiyear charcoal yielded, as expected, a somewhat older average: 3370 ± 6 BP. Both dates are more precise than the standard deviation (σ) of the calibration curves and the absolute standard of oxalic acid. Calibration of the above Jericho dates is a bit premature, because several groups are currently testing the accuracy of both the 1986 and 1993 calibration curves. Nevertheless, preliminary calibration results are presented for comparison, based on 4 different calibration curves and 3 different computer programs. Wiggles in the calibration curves translate the precise BP dates into rather wide ranges in historical years. The final destruction of MBA Jericho occurred during the late 17th or the 16th century BC. More definite statements about the calibrated ages cannot be made until the accuracy of available calibration curves has been tested. Development of calibration curves for the Eastern Mediterranean region would be important.

Radiocarbon challenges archaeo-historical time frameworks in the near East : The Early Bronze Age of Jericho in relation to Egypt

Our stratified radiocarbon dates from EB Jericho (Trench III) on short-lived material are significantly older than conventional archaeo-historical time frameworks. The calibrated 14 C date of Stage XV Phase li-lii (Early to Middle EB-I Kenyon) is 100-450 years older. Stage XVI Phase lxi-lxii (Early EB-II Kenyon) is 200-500 years older. Stage XVI Phase lxii-lxiii (destructive end EB-II) is 200-300 years older. Stage XVII Phase lxviii a - lxix a (Early EB-III) is 100-300 years older than conventional archaeo-historical time estimates. As the beginning of the Chalcolithic in the Near East has become a 1000 years older, from about 4000 in the 1960s to about 5000 BC in current perception based on 14 C dating, it should not be surprising that the Early Bronze Age and related Egyptian Dynasties also yield 14 C dates that are older by a few hundred years than current archaeo-historical time frameworks. Egyptian chronology should not be regarded as ultimately fixed. Egyptologists in the first half of the 20th century gave much older dates for the earlier Dynasties. The new 14 C evidence is overwhelmingly in favor of an older Early Bronze Age and older dates for Dynasties 1-6.