Regarding the issue of herbicides that only weeds but not crops, I believe that many friends are also very curious. Indeed, this issue is farmer friends who have been planting land for many years. Some of them are not very clear about why the same plants are all plants. After the herbicide, the grass dies and the crops are normal? Yingkou Sanzheng Gas Co., Ltd., does the herbicide liquid also identify which are grass and which are crops? In fact, it is not so magical. The main reasons are the following 3 points. The helper will take everyone to take a look:

1、Discrimination in morphological structure

Although weeds and crops are both higher plants, they are different in morphology and structure. For example, common weeds have broad leaves, pointed leaves and sedges, while crops also have sharp leaves and broad leaves. For example, wheat belongs to sharp leaves, while Artemisia sibiricum, Swine Salamander, and Pona are broad-leaved grasses. At this time, we choose broad-leaved herbicides (such as tribenuron-methyl, dimethyltetrachloro, fluroxypyr, etc.) ), these agents are only effective on broad-leaved weeds, while wheat belongs to sharp leaves (the specific molecular structure, this article will not introduce in detail, it involves too many technical terms, it is not easy to understand), so miscellaneous The grass is killed and the crops grow normally.

2. Position difference principle

The principle of level difference is mainly in the closed herbicide, or a small example to illustrate, in the case of corn, many friends will apply the closed herbicide in time after the corn is sowed. When the liquid is sprayed, a layer will be formed on the soil. In general, weeds emerge earlier than corn. At this time, the weeds will absorb the liquid of the closed herbicide and cause death. However, when corn emerges late, it will germinate and grow normally under the protection of the cover soil. It is the principle of position difference.

3. Safener

Nowadays, many post-emergence herbicides of crops are added with safeners (wheat, corn, peanuts, etc.), such as mesosulfuron-methyl, which is used in addition to wheat jelly. Generally it is a safener, such as corn herbicide, nicosulfuron·mesotrione·atrazine + adjuvant, this adjuvant is actually a safener, the role of safener is to protect crops from being drugged by herbicides However, these safeners do not work on weeds (the specific principles are also more complicated. If you have time later, the helper can give you a special talk about safeners, welcome to pay attention). The final result is the death of weeds. The crops grow normally.

The above 3 points are the reasons why herbicides only kill weeds but not seedlings. However, there is an exception to a class of herbicides. No matter what is added, the grass and seedlings will be removed. It is a biocidal herbicide, such as glyphosate, commonly known as "See Green Kill", after hitting it, whether grass or seedlings, as long as they are stained with liquid medicine, they will be killed.