AGRICULTURE REPORT - Food for Crops: How to Get the Most Fro

AGRICULTURE REPORT - Food for Crops: How to Get the Most From Organic Fertilizer
By Mario Ritter

Broadcast: Tuesday, August 23, 2005

I'm Shep O'Neal with the VOA Special English Agriculture Report.

There are many different products that farmers can use to add nutrients¹ to soil. Organic fertilizers usually come from animal waste, plant material or treated wastewater.

Farmers who raise animals have a ready-made fertilizer to mix into the soil. However, animal waste must be treated in order to make good fertilizer.

Composting is a natural method. It uses the action of bacteria and other organisms to break down the manure² into fertilizer. The manure must be mixed with a material that provides carbon, such as wood cuttings. The carbon supports the growth of the organisms.

It is important to mix in enough carbon-supplying material. If there is too little, nitrogen in the waste will release ammonia gas and smell terrible.

Composting also requires the right amount of water and air. The compost material should be loose and easy to turn with hand tools. The compost should be about fifty to sixty percent water. Too much water will mean that air cannot reach all the material. This will cool the compost. It will slow the organic activity and cause a bad smell. Too little water will also stop the activity.

The process of composting produces heat. If conditions are good, the compost material should reach about fifty to sixty degrees Celsius³. This heat kills dangerous organisms in the animal waste. Experts say all of them will be killed if the material stays at fifty-five degrees for fourteen days.

It takes three to seven months for compost to become ready to use as fertilizer. After this time, the material will have lost twenty to sixty percent of its mass.

Waste products provide one fertilizer resource. Some crops supply limited amounts of nutrients to the soil. Beans release nitrogen. Crops like alfalfa can be left to break down.

There are many different kinds of manufactured fertilizers. The most commonly used mineral fertilizers are nitrogen-based. Nitrogen from the air is mixed with hydrogen from natural gas. This process produces ammonia gas. Other elements are then added to the ammonia.

Different crops demand different mixtures of nutrients. Many farmers invest in special fertilizers designed just for the kinds of crops they grow.

This VOA Special English Agriculture Report was written by Mario Ritter.  We will also have links to more information about composting. I'm Shep O'Neal.

1 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

2 manure   

n.粪，肥，肥粒；vt.施肥

参考例句：

• The farmers were distributing manure over the field.农民们正在田间施肥。
• The farmers used manure to keep up the fertility of their land.农夫们用粪保持其土质的肥沃。

3 Celsius   

adj.摄氏温度计的，摄氏的

参考例句：

• The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
• The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。