Weed Control in Wheat Field
Major weeds in winter grain crops in India are Board leaved weeds like Lamba quarters (Chenopodium sp.) Wild safflower (Carthomus Osycantha). In some parts of the country, perennial dicot weeds viz. canda thistle (Cirsium avenses), Field Bind weed (Convalvelus arvensis) are found.
Annual Grasses like Wild Oat (Avenu fatua), Chanry grass (Philaris minor).
Due to weeds competition, many tillers wither before earing stage. Ears get shortened due to prolonged competition, less number of grains/ear and less weight of grains
The weed seeds get admixture in the crop seed and reduce grain quality.
Weed Control Practices:
a. Mechanical Interculturings:
Mechanical intercuturing are not possible due to loss row spacing. Hence practices like proper seed bed management. Use of clan and high viability seeds crop rotation etc. are useful. One to two hand weddings control simple annual weeds to boost crop production.
b. Herbicidal Control of Broad Leaf Weeds:
2, 4-D and MCPA are the most widely used herbicides, to control weeds in wheat, oat and barley. 25 to 30 days age sage is sensitive to 2.4-D (rot primordial). Rate at fully tillered stage is ½ to 1 kg a.i/ha.
c. Control of Difficult Annual Broad Leaf Weeds:
Diuren and Limuren 0.5-1 kg/ha as pre and post emergence herbicides. A mixture of Dicaba (0.125 to 0.250 kg/ha). Amine, 2,4-D 0.5 kg/ha) as post emergence and Picehloram (0.30 to 0.42 kg/ha) as selective.
d. Control of Annual grasses:
Wild oat can be successfully controlled in wheat and barley by pre-planting treatment of Diallate and Triallate and post emergence spray of Barban Canary Grass : Nitrogen, tribunal, Limuron, Alkachlor.
e. Other Annual Grass – (Other than wild oat):
Trifluralin – (Pre – plant / post emergence) 0.6 to 1.5 kg/ha, Diuren (Pre-emergence) @ 0.08 to 1.6 kg/ha. Pre-emergence @ 2.25 kg/ha. TCA Post emergence @ 0.5 to 0.75 kg/ha.
f. Control of Perennial Weeds:
Barmuda grass (Cynodon dactylon), Dalapon or Amitrole /22 kg/ha pre-planting paraquat 1 kg/ha. Pre-sowing 2 weeks before shallow summer tillage and Attrazine. Spot treatment with MSMA, DSMA also controls it.