深入了解如何浇灌树木

    This is the VOA Special English Agriculture Report.
    这里是美国之音慢速英语农业报道。

    Some trees can survive a long time without water. Think of trees that grow in the desert. But other trees may need more moisture than they can get from rainfall or from the air -- from, say, coastal or mountain fog.
    有些树木在缺水的情况下也能存活很长时间,例如沙漠中生长的树木。但有些树木可能无法从降水和空气中获取充足的水分---沿海或山雾的空气都能提供水分。

    The soil stores moisture during cooler weather. But most of that moisture is gone by the middle or end of the hottest months of the year.
    土壤可以在凉爽天气期间储存水分。但其中大部分水分在一年中最热那几个月的中期或后期就会用完。

    Trees and other plants can look thirsty. Leaves can become droopy and hang downward. They can also turn yellow. Yellowing can be a sign of too much water. But it can also be a warning sign of too little water.
    树木和其它植物能看出来干渴。叶子会枯萎下垂,还会变黄。泛黄可能是水分过剩的迹象,但也可能是水分不足的警告迹象。

    The Vacaville Tree Foundation is a volunteer community group in California. It has advice for watering newly planted trees and established trees.
    Vacaville树木基金会是加州的一个志愿者社区组织,该组织对浇灌新种植的树木和已长成的树木有些建议。

    With a newly planted tree, the roots have not yet spread out from the root ball. The root ball can become dry faster than the dirt around it. So put water on the area of the root ball and the surrounding soil until the roots become established.
    新种植的树木根部尚未从根球中展开。根球比周围土壤更容易变干。所以在根部完全长成之前,在根球区域及其四周土壤浇水。

    Once a tree is well established, water deeply instead of often. The amount of water needed depends on the tree and the soil. Clay soils hold water for longer periods while sandy soils hold less water. During the hottest season, a deep watering may satisfy a tree for anywhere from ten days to four weeks.
    一旦树木长成,就可以一次浇透而不用频繁浇水。水量需求取决于树木和土壤。粘土可以长时间保持水分,而沙土保持的水分就很少。在最热的季节,浇透一次可以满足任何地方的树木十天到四个星期的需求。

    Part of skilled watering is knowing to stop when the soil needs a little time to absorb the water. Otherwise the water runs off the surface and gets wasted.
    浇水的部分技巧是知道何时停下来给土壤吸收水分的时间。否则水就从土壤表面流失浪费了。

    Ted Swiecki is a plant scientist in California with the Phytosphere Research company and the Vacaville Tree Foundation. He says people should not water established trees at the base of the trunk. This can harm the tree.
    Ted Swiecki是加州的一位植物学家,就职于植物圈( Phytosphere)研究公司和Vacaville树木基金会。他表示,不要在已长成树木的树干底部浇水,这样会伤害树木。

    Too much water in the soil at the base of a tree can lead to the growth of fungi. If the area is too wet, harmful organisms have a better chance to invade the tree and cause disease.
    树干底部的土壤含水过多会导致真菌滋生。如果这一区域过于潮湿,有害生物就有可趁之机侵入树木导致疾病。

    Mr. Swiecki says this is true especially in Mediterranean and semi-dry climates. Many trees in these climates have adapted to having a dry area near their base during the hottest season.
    Swiecki先生表示,这一观点特别适用于地中海和半干旱气候。这类气候的很多树木已经适应了在最热的季节期间保持树干底部干燥。

    TED SWIECKI: "Water displaces air in the soil. And roots are aerobic; they require oxygen (for the soil) to function properly. So if you keep the soil saturated and there's no air there, and then you are basically starving the roots for oxygen."
    TED SWIECKI:“水分取代了土壤中的氧气。而根系是需要氧气的,它们需要氧气维持正常机能。所以如果土壤水分饱和,没有空气,根部就基本处于缺氧状态。”

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