国際農林水産業研究センターは、平成5年10用1日に熱帯農業研究センターを改組して設立された。これにともなって、研究活動領域もこれまでの熱帯・亜熱帯に加えて、温帯・冷涼帯も含めた開発途上地域全体に拡大し、農林水産業及び環境問題の解決に向けて研究を行なうこととなった。海外情報部においても、開発途上地域における農林水産業研究の効率的推進のため、地域別農業特性に関する諸情報の収集及び分析・評価を進めている。
国際農林水産業研究センターの地域別農林水産業特性の収集・分析は、アジア地域では主として東南アジア諸国を中心に進められ、中央アジアや西アジアにおける農林水産業の生産動向や技術に関する情報収集はほとんど実施されていない現状にある。とりわけ中近東では、地下水潅漑、オアシス農業や遊牧など、特徴的な乾燥地農業が展開されているにも関わらず、引き続く戦乱や社会的混乱のために調査の機会が少なく、他のアジア地域と比較して農林業情報の収集・分析が著しく遅れた地域である。平成3年度に実施した中近東北部のシリア、トルコでの調査に続いて、平成5年4月1日から29日まで、アラビア半島中南部のサウジアラビア、イエメン、オマーンの3カ国における農業特性とその技術動向の調査を実施した。この調査は、上記の3カ国において当センターが実施した初回の現地調査である。
乾燥地は一般に降水量の少ないところを指すが、より正確な定義では、年間を通じて降水量より蒸発散量が多い地域を意味する。こうした定義に従って世界の乾燥地を眺めると、南緯30°、北緯30°を中心とした中緯度地帯に乾燥地は多く分布し、その面積は世界の陸地の31%、48百万km2にも及ぶ。乾燥地面積が大きいアフリカ大陸とアジア大陸では、それぞれ陸地の58%及び37%を占めている。アジア大陸の乾燥地は西アジアから中央アジアにかけて広がり、その西端に今回の調査対象地域であるアラビア半島が含まれる。乾燥・半乾燥地において展開される農業の形態は、基本的に天水農業（Dry farming）と灌漑農業(Irrigated farming）に大別される。
こうした乾燥地農業の基本概念を念頭に置きながら現地を訪問してみると、砂漠に点在する伝統的オアシス農業と牧畜、海岸平野部や山岳高原部の天水農業など、地勢や気象条件によってその農業形態が実に多様である。さらに、サウジアラビア、オマーンでは、広大な砂漠の中で地下水（化石水）に依存した近代的大規模灌漑農業や酪農及び施設園芸農業が展開されている。今回の調査は、広大なアラビア半島の3カ国を短期間に飛行機や車で移動、訪問しながら実施したため、得られた情報は極めて限られたものではあるが、各地域における農林業特性の調査と併せて、現地機関の研究体制や技術動向に関する情報収集を可能な範囲で実施した。そこで得られた情報をもとに、本報告書では、現地の農業統計に基づく農畜産業生産の現状と特性を分析して取りまとめ、併せて研究報告書の中から主要な研究成果を要約して補足説明資料とした。本研究資料が、今後のアラビア半島諸国や広範な乾燥地域との研究協力を推進する上で参考になれば幸いである。
本調査の準備や現地での行程に際して、鳥取大学乾燥地研究センター、現地の日本大使館、国際協力事業団（JICA）及び訪問国の諸機関など、内外の多くの方々から貴重な情報の提供や御配慮を受けた。ここに記して、心から謝意を表する。
The present status of agriculture and research activities including agricultural statistics in the central and southern Arabian Peninsular countries were investigated through a survey conducted in April 1993.
The total land area of the kingdom of Saudi Arabia amounts to 215 million ha with a population of 14.9 million. Agriculture accounted for 1.35 million ha of the land area (0.63%) and 5.8 million people (39%) were engaged in agriculture in 1990. The agricultural sector accounts for 11.3% of general domestic product.
Main agricultural products are cereals, especially wheat. Wheat production increased drastically from 0.82 million ton in 1983 to 3.46 million ton in 1990. The 4.2 times increase within 7 years was attained through political incentives (financial compensation) and the introduction of a modern irrigation system (the so-called center pivot method). In contrast, sorghum production is still practiced traditionally in the western part of the country along the Red Sea.
Other important crops next to cereals are forage crops, vegetables and fruits. Alfalfa as forage crop, tomato and watermelon as vegetables and dates as fruits are very important crops. However, prevailing pests and diseases, such as yellow stunting virus in watermelon and leaf miner in citrus fruit have led to a decrease of yield and quality of the products.
The National Agriculture and Water Research Center (NAWRC) is the main research organization in Saudi Arabia with networks throughout the country in combination with extension projects.
The Republic of Yemen is located in the south-western part of the Arabian Peninsula. Since the country is covered with high mountains, precipitation is higher than in other Arabian countries and agriculture is the major activity for the national economy.
The total land area amounts to 55 million ha with a population of 11.5 million. Agriculture accounted for 1.48 million ha of the land area (2.7%) and 6.6 million people (57%) were engaged in agriculture in 1988. Agriculture accounts for 22% of the general domestic product. Main producing areas are Al-Hodeidah and Sana's districts.
Cereals play a major role, accounting for 71% of the cultivated area followed by vegetables, fruits, forage crops, pulses and cash crops accounting for about 6% of the total area each.
Main cereal is sorghum which covers 50% of the total area under cereal production,followed by millets (14.2%) and wheat (13.6%). Except for cereals, other important crops, are potato, tomato and watermelon as vegetables, grape and date as fruits, coffee as cash crop and sorghum as forage crops. However, Abyssinian tea (Catha edulis), called Qat locally, is also an important cash crop because of its palatability and the higher market price it fetches.
Yemen depends mainly on imports for food consumption. The increase of domestic food production is an important target for the government. For this purpose, research works are carried out by the Agricultural Research and Extension Authority (AREA) under the Ministry of Agriculture and Water Resources. However, the organization is not operating efficiently because of the political problems associated with the fusion of former North and South Yemen.
The land area of the Sultanate of Oman amounts to 31.3 million ha with a population of 1.55 million. Agriculture accounted for 55 thousand ha of the land area (0.26%) and 0.62 million people (38%) were engaged in agriculture in 1992. Agriculture accounts for 3.6% of the general domestic product. Since the population is too low to supply the manpower required for the economy, Oman depends fully on foreign workers for various economic activities. The number of foreign workers was almost 0.4 million in 1990.
Date is the main agricultural product which is cultivated over 24 thousand ha, or 44% of the total area under agriculture. Vegetables, such as tomato and watermelon, are important crops next to date. Area under vegetable cultivation reached 6 thousand ha (11 % ) in 1988.
On the other hand, cereal production is very low and does not meet the domestic demand. Therefore, 0.29 million ton of wheat was imported in 1987. Fishes are also appreciated by consumes in Oman.
The Department of Agricultural Research is in charge of the governmental research activities in Oman. However, the research staff working in this organization are mostly foreigners. The graduates from the newly established Sultan Qabos University are gradually replacing foreign researchers.
The three countries located in the central and southern Arabian Peninsula are facing common constraints on agricultural development including dry and hot climatic conditions and lack of irrigation water. Main season for crop production is winter. Therefore, strong emphasis is placed on for selection of heat-tolerant varieties and efficient use of water.
In the farmers' fields, the decrease of the underground water level and the salinity of irrigation water and soil result in serious problems in agricultural production. There is an urgent need for the development of technology and international information network to solve the problems faced by arid land agriculture.
The authors would like to express their gratitude to the directors of various national agricultural organizations in Saudi Arabia, Yemen and Oman for their administrative support and encouragement during their visit to these countries. Deep appreciation is also expressed toward many researchers in the agricultural research institutes and stations for giving valuable information and suggestions.