雅思大作文范文:农业化肥和机械运用的负面影响

由于肥料的研发和机器的改进，食物的产量大幅的提高了并且价格便宜。有的人认为这会负面的影响人类健康和当地社区。问：何种程度上说你是否同意？

这是一道观点类作文，在审题时候一定要注意这道题的限定词，因为“developed fertilizers and better machinery” 使得食物“produced in greater amount and much cheaply”，有人认为这对“human health and local communities”是有害的，我们提出观点和论证的时候要紧扣这些限定范围。比如有同学一看到产量增加，然后就把“这会减少全人类饥饿”作为论点，那就跑题了。

然后我们一起来看下，肥料、机械以及粮食产量增加价格变低分别对人类健康和当地社区产生什么问题，以及是否可以改善。

首先来看肥料，大部分肥料里面普遍含有一定的化学成分，而这些成分可能会附着于农作物上。这些化学成分达到一定的累积会对人体造成伤害。同时在使用这些肥料的时候，这些化学成分也会被释放到环境中，造成对土壤，水源以及空气甚至生态系统的破坏，比如使土壤硝酸盐浓度过高。但是随着化肥技术进一步发展和进步，有机化肥可以很好的降低食品生产种植过程中对环境的负担和对健康的影响。

然后来看机械，农业机械的运用好处有三方面，一是用机械替代人力能够更快的完成犁地、播种、浇水、施肥、收获等步骤，有效避免错过农时，大幅提高耕种效率；二是因为生产效率的提升，农民花更少时间就能完成原来的工作，意味着他们能够开垦更多的农田；三是机械相比人力或牲畜在耕地能更深，进而使得农作物获得更好的成长环境。但是机械的过度使用容易对环境造成负面影响，一是机械本身功率较大需要消耗石油，容易产生排放污染。二是使用机械过度深耕土地，容易破坏土壤结构、造成营养的流失和产能的降低，并且难以恢复。

后来看经济问题，食物产量上升价格降低，对于吃的人来说可能是好事，但对于农民来说，意味着其收入降低，如果想获得更高的收入意味着要耕种更多的土地，但是现实中由于耕地饱和等原因可能难以实现。而化肥和机械本身又是不小的支出，当农民发现耕地不赚钱后，便会放弃耕种外出务工，这就造成了当地劳动力的流失，进而出现留守儿童或老人的问题。

As the world’s population continues rising, machines and fertilizers are used to maximize the amount of food produced and stabilize the price of food within an affordable range. However, while we are trying hard to produce enough to feed the global population, we still fail to limit the adverse effects of agricultural activities on human health and local area.

The use of fertilizers and other farm chemicals like herbicides and pesticides, is unsustainable and physically and environmentally damaging.  Those farm chemicals can be toxic especially when organi*s are exposed to high concentrations.  Even if fertilizers are scientifically applied to crops in a way which will prevent them from accumulating on the food in harmful concentrations, they are difficult for our bodies to process and consume large amounts of food treated in this manner, which would probably result in health impacts.  Worse still, the application of these chemicals will spoil the land, waterways and air.  Once released into the atmosphere，they are absorbed into the soil, mixed into air or digested by tissues of simple organi*s, all of which enable them to grow to toxic concentration and remain threat for the whole ecosystem.

For another, the modernization and mechanization of agriculture also impose detrimental impact on the environment.  During the past few years, the weight and size of the machinery had increased significantly, which in some cases exceeded the soil’s tolerance for load.  The operation of machines to irrigate the land would damage the soil structure, making it more vulnerable to erosion and causing greater loss of nutrients and poorer crop yields.  Such damages caused by heavy agricultural machinery are usually more permanent and hard to recover.

In conclusion, although various scientific and technological methods are identified to enable farmers to grow crops more efficiently while maintaining yields，a sustainable and healthy agriculture system has yet been achieved.

affordable  负担得起

herbicides  除草剂

organi*  有机体

digest  消化

detrimental  有害的