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大会报告首先指出,现在对粮食生产的需求在不断增长。热带、亚热带地区的一些国家,由于现有土地的负担过重,且低地中其余的土地又不能利用,故注意力已转向旱地土壤,甚至已砍伐森林。湿润热带地区具有高产潜力。根据对太阳辐射能和有效雨量的换算,热带地区谷物生产的潜力很高,在理论上每年每公顷产量可高达30吨。然而由于在短促的关键性的生长期中水分亏缺、土壤pH低和缺磷等原因,限制了这种潜力的发挥。郁蔽的成年橡胶树的干物质生产量,每年每公顷为30—35吨,还有1.5—2.0吨的干胶。这就说明了为什么在热带地区旱地农业是值得考虑的。有人说“旱地”是指主要分布在热带亚热带地区丘陵和山地上的种植农作物和木本植物的耕地,主要靠“雨水供养”。我认为,应不考虑地形,只要是靠“雨水供养”的都应该看成是“旱地”。在中国热带和亚热带地区,旱地占耕种土壤的三分之一以上。有人指出,甚至在两千年前,就已有关于旱地土壤和农业生产的书籍。然而,由于人们掠夺式的经营和疏忽大意,使这类土壤严重退化。我们应该共同努力,为了子孙后代保护好这些土壤,这次旱地会议就是很及时的第一步。
The report of the General Assembly first pointed out that the demand for food production is now on the rise. In some tropical and subtropical countries, due to the overburden of existing land and the inaccessibility of the rest of the lowlands, attention has turned to dry land and even deforestation. Wet tropical areas with high yield potential. Based on the conversion of solar radiation and effective rainfall, the potential for cereal production in the tropics is high, with theoretically up to 30 tons per hectare per year. However, this potential is limited by water deficits, low soil pH and phosphorus deficiency during the short, critical period of growth. Depleted adult rubber tree dry matter production, 30-35 tons per hectare per year, there are 1.5-2.0 tons of dry glue. This explains why dry farming in the tropics is worth considering. Some people say that “dry land” refers to the cultivated land for planting crops and woody plants mainly in the hills and mountains of the tropical and subtropical regions, mainly relying on “rainwater supply.” In my opinion, the terrain should not be taken into account. Anyone who depends on “rainwater supply” should be regarded as “dry land.” In tropical and subtropical China, dry lands account for more than one-third of the cultivated soil. It was pointed out that even two thousand years ago books were available on dryland soil and agricultural production. However, because of their predatory management and negligence, these soils have been seriously degraded. We should work together to protect these soils for future generations and this dry land meeting is a very timely first step.