What kind of herbicides are used for resistance to malignant weeds such as barnyardgrass, Pleurotus ostreatus, Trigonium przewalskii, spring onions, rice paspalum and so on?

When the peak season for the use of herbicides in rice fields comes in mid-June every year, many rice farmers will ask: what kind of herbicides should be used for malignant weeds such as resistant barnyardgrass, mushrooms, horsegrass, spring onions, rice paspalum and so on?

1. Control of malignant weeds such as alisma alisma, Pleurotus ostreatus, Trigonium przewalskii, spring onion and so on.

With 48% of paicaodan or prednisone 180 ml, plus 56% of imported agricultural dos or dimethyl tetrachloride 10 grams, mixed with water 30 jin, after drainage on weed stems and leaves spray, can spray 600 million 700 square meters. It can control many kinds of malignant weeds such as Pleurotus ostreatus, Chinese cabbage, orchid cauliflower, trigonous grass, spring onion, small catweed and so on, which is safe for rice. Using a certain amount of dimethyltetrachloride every year can make the rhizomes or bulbs of these malignant weeds gradually shrink or rot away. Weed seeds cannot mature either. Coupled with the autumn turning over the ground, the rhizome and corm can reduce the regeneration base of rhizome and corm in the next year after freezing and drying in winter. When raking the ground in the spring, salvage the floating roots and bulbs. In this way, dimethyltetrachloro plus prednisone was used for three consecutive years, and the malignant weeds were sprayed on stems and leaves at the end of tillering, which could completely control perennial rhizomatous and bulbous weeds such as alisma orientalis, Pleurotus ostreatus, Trigonium, spring onions and so on.

II. Control of older barnyardgrass

If you have older paspalum grass, you can use 25g / L pentafluorosulfonamide (Daojie) 80ml / mu (667 kg), plus 40-50% dichloroquinolinic acid 50g, 30 jin of water, stem and leaf spray. Use a nebulized sprayer.

Be careful

If you enter the young panicle differentiation stage, you can not use dimethyltetrachlor, pentafluorosulfonamide, dichloroquinolinic acid and other chemical herbicides, otherwise it will cause drug damage and reduce yield! It is best to spray in the morning and evening, and the spray temperature should not exceed 30 ℃.

The damage of herbicides and the control effect of weeds are affected by many factors. The above formula is for reference only! Or try it first and then use it.

Weeding steps in paddy field

Drain (or dry naturally) and then return to the water:

First of all, why do you have to drain the water first and return the water 24 to 48 hours later? it is very troublesome to do so, can you not drain or return the water? In particular, large growers often lead to grass shortage due to large planting area, untimely pumping, unscheduled time, incomplete drainage, untimely backwater and water conservation, resulting in herbicide damage or poor chemical effect, resulting in a reduction in rice yield or no harvest.

①, using herbicide to drain water first, then returning water after 24 hours, and retaining water for 7 days can not only effectively kill weeds and ensure the safety of rice, but also the key to effectively control the secondary damage of weeds.

②, why should the water be drained when using herbicides?

There are usually five ways to control weeds in paddy fields by making use of the differences in morphology, physiology, growth and development between rice and weeds and some characteristics of herbicides to avoid drug damage to rice. Among them, chemical weeding usually adopts four ways: time difference selection, position difference selection, morphological selection and physiological selection, while physical weeding adopts one way of spatial selection. We can choose a variety of means to transplant and throw seedlings, such as position difference, jet lag, morphological difference, physiological difference and spatial difference to control weeds. On the other hand, the weeds in the direct seeding field usually germinate before the seeds, grow at the same time as rice, or even precede the growth of rice. The semi-arid and semi-humid environment in the early stage of direct seeding field is very beneficial to the growth of weeds, and position difference, time difference and spatial difference can not be used. Only morphological difference and spatial difference can be selected for weeding. Therefore, it is very difficult to weed in the direct broadcast field.

The main purpose of draining dry water before using herbicides in rice fields is to make all weeds come out of the water and fully contact the solution, so as to achieve a better weeding effect. If there is no drainage or the field is uneven and the drainage is not thorough before using herbicides, it will lead to no contact with the solution, resulting in weeding failure and secondary harm of weeds.

③, why does it take 24 hours to return water when using herbicides?

Rice, barnyardgrass and Artemisia chinensis are all Gramineae plants with close genetic relationship. In fact, in the process of chemical elimination, they all accept herbicides. The reason why weeds die and rice does not die is that we take advantage of the different physiological characteristics of rice and weeds. Rice can decompose these herbicides (such as cyhalofenoxate, pentafluorosulfonamide, dioxyether, etc.) and require timely backwater because rice is more dynamic and has better antidote ability when there is water. Therefore, it is required to return water in time when using it, which on the one hand is one of the most important reasons to prevent drug damage to rice.

On the other hand, 24-hour backwater is required to ensure the efficacy of herbicides, and field drying is one of the important means to promote the development of rice roots (dry roots and aerobic roots). Of course, this means is also conducive to the development of weed roots. If the return water is not timely and the field is short of water after the use of herbicides, it will cause the rapid development of weed roots, which will make it possible for weeds to carry herbicides and directly lead to weeding failure.

Why does ④ use herbicides to retain water for 7 days?

The function of water conservation is very simple, that is, to achieve the goal of controlling grass with water. The use of water layer (usually 3mi 5cm, not too deep or too shallow) can block the secondary germination of weeds. Reasonable water conservation can promote the early development of strong rice seedlings, achieve the effect of using water to control weeds, promote seedlings and inhibit weeds, and improve the effect of herbicides. After 7 days of water conservation, (must be combined with topdressing nitrogen fertilizer, because where there is rice paspalum, rice is occupied by the field space nutrition, the growth is poor. Therefore, fertilizers should be applied after weeding. Only in this way can the rice grow neatly. Achieve a high-yielding shelf.