1、对转基因的看法转基因是利用现代分子生物技术，将某些生物的基因转移到其他物种中去，改造生物的遗传物质，使其在形状、营养品质、消费品质等方面向人们所需要的目标转变。当今世界对于转基因技术的应用持有不同的看法，那些认为这是一种危险现象的人坚决反对转基因技术的应用。我认为，转基因技术的出现是科学进步的标志，没有任何人能准确说出作物在转基因后是否有害，转基因技术能商业化也是科学家们经过多次实验的结果，因此我们应理性对待转基因。转基因技术给我们带来的利，是很明显的.首先，转基因技术可以提高单位面积作物产量，不言而喻，产量是育种的重要目标，而且可以缓解世界粮食短缺矛盾。第二，通过转基因技术可培育高产、优质、抗病毒、抗虫、抗寒、抗旱、抗涝、抗盐碱、抗除草剂等特性的作物新品种, 以减少对农药化肥和水的依赖.第三，转基因可能提供廉价的和有营养的食物,比如胡萝卜有更多的抗氧化剂 此外，转基因食品可以摆脱季节、气候的影响，让人们一年四季都可吃到新鲜的瓜菜。总的来说，转基因技术是科学的进步，是发展的必然。然而，我们应尊重每一个人的选择。Genetically modified (gm) refers to transferring selected individual genes from one organism to another by using modern molecular biological technology in order to modify genetic properties of organisms.The purpose is to meet the demand of people in the shape, nutritional quality, consumption quality, etc. Nowadays ,there are many different views of GM. Those who deem it is a dangerous signal and undesirable impact set themselves against the application of transgenic technology.As for me ,The emergence of genetically modified technology is the mark of scientific progress.No one can clearly tell crop is harmful after GM. Meanwhile, it will lead to the commercialization and its the result of the scientists after many experiments.Hence,we are supposed to treat GM rationally.The following benefits could account for the necessity of GM. First of all,Genetic modification may improve the yield per unit area of crops.It is serious that production is the goal of breeding,and it can relieve the contradictions of the world food shortage.Second,through transgenic technology to cultivate high-yield, high-quality, antivirus, insect resistance, cold resistance, drought resistance, conferring, salt resistance, herbicide resistance characteristics of new crop varieties.So that it can reduce dependence on fertilizers and water.The third,GM may provide inexpensive and nutritious food,like carrots with more antioxidants.In addition,Genetically modified food can get rid of the influence of season, climate, let people can eat fresh vegetables all the year round。In general, the transgenic technology is the progress of science, is the necessity of development。However,we should respect the choice of each person. (249 words)2、N 肥利用的优缺点 氮肥、磷肥、钾肥是农业生产中最主要的化肥。氮肥是指含有作物营养元素氮的化肥。元素氮对作物生长起着非常重要的作用，它是植物体内氨基酸的组成部分、是构成蛋白质的成分，也是植物进行光合作用起决定作用的叶绿素的组成部分。然而，氮肥的利用优点与缺点并存。氮肥利用的优点如下：第一，提高生物总量和经济产量；第二，改善农产品的营养价值，特别能增加种子中蛋白质含量，提高食品的营养价值。氮是农作物体内蛋白质的主要成份，没有氮，就不能形成氮白质，没有蛋白质也就不可能有各种各样的生命现象。第三，氮还是叶绿素和许多酶的成份。足够的叶绿素以及大量的酶被证明是至关重要的. 叶绿素是作物进行光合作用必须的物质，而酶是作物体内各种物质转化的催化剂。此外，核蛋白、植物碱也都含氮。从而可以看出，氮肥的利用有诸多优点。然而,事物都有两面性 ,氮利用的缺点也是 显而易见的。 第一，氮肥中不含有机质、腐殖质，因此大量使用氮肥，土壤由于有机质和腐殖质的缺乏，土壤团粒结构遭到破坏，造成土壤板结，农植物产量下降。第二，过度使用氮肥，是造成土壤和水体污染的一个重要原因。第三，氮肥因为易挥发、流失，利用率只有 30%-50%，利用率低。第四，危害人体健康。大量施用化肥，易使蔬菜中硝酸盐含量超标，形成致癌物质。As we all know,Nitrogen fertilizer, phosphate fertilizer, potash fertilizer is the main chemical fertilizer in agricultural production.Nitrogen refers to the fertilizer that contains crop nutrient elements of nitrogen.Nitrogen element plays a very important role for crop growth,it is part of the plant amino acid in the body, a protein component and the part of chlorophyll which necessary role in photosynthesis.Nevertheless,the advantages and disadvantages of Nitrogen fertilizer exist side by side.The advantages of nitrogen use is as follows: First,it can improve the biomass and economic yield.Second,improving the nutritional value of agricultural products is serious.Particularly,it may increase protein content in the seeds as well as improve the nutritional value of food.Nitrogen is the main protein ingredients in the crop.No nitrogen, crops cannot form the protein.No protein ,it is impossible to have all sorts of phenomenon of life.Third,Nitrogen is the composition of chlorophyll and many enzymes.Sufficient chlorophyll as well as plenty of enzymes proves to be of vital importance.Chlorophyll plays a very important role in crop photosynthesis.Enzyme as a catalyst for the crop while material transforming in the body.Moreover, Nucleoprotein and vegetable contain nitrogen.Consequently,nitrogen fertilizer use has plenty advantages.However,every coin has two sides,the disadvantage of nitrogen use also is obvious.First and foremost,as we all know,nitrogen fertilizer does not contain organic matter and humus.Soil aggregate structure will be destroyed due to lacking of organic matter and humus when nitrogen is abused.That could account for the phenomenon of soil harden and the decline in output.Second,excessive use of nitrogen fertilizer is an important cause of soil and water pollution.Moreover,its use ratio is of only 30%-50% in that nitrogen fertilizer is volatile and erosion.Last but not least,its easy to make excessive nitrate content in vegetables which can form carcinogens with a lot use of nitrogen fertilizer.In a word,we are supposed to make use of the advantages of nitrogen fertilizer and abandon its disadvantages. (313 words)3、农业免耕的优缺点？免耕是一种不翻动表土，并全年在土壤表面留下足以保护土壤的作物残茬的耕作方式。免耕技术起源于美国，20 世纪 60 年代，