Organic farming aims to minimize environmental impact through methods like crop rotation, compost, biological rather than chemical pest control, and green rather than synthetic fertilizers. Crop rotation keeps the biodiversity of the soil strong. Planting the same crops over and over in the same soil robs the soil of its nutrients over time and results in the need for fertilizers and soil additives. If crops are rotated, there's no need for additives. Also, when chemical pesticides are not used on crops, it protects the water table from those contaminants.
Organic produce is also free from genetic modification, which is when the DNA of a plant is altered to make the fruit or vegetables more desirable. For example, genetic modification may cause the plant to produce more fruit or vegetables, or it may make the plant resistant to certain diseases. Some people object to genetically modified organisms (GMOs), particularly when they're designed to be herbicide resistant, which means that a farm can soak an entire field in herbicide to kill the weeds, and the crop will still survive. Genetic modification skeptics have concerns about what effect this herbicide soaking will ultimately have on the soil and on the human body.