Weed management

• 12 to 72 % reduction in cane yield depending upon the severity of infestation.
• Major weeds seen in sugarcane fields are: Cyprus rotundus; Cynodon dactylon, Sorghum helepense, Panicum spp, Dactylocternium aegyptium, Chenapodium album, Convolvulus arvensis, L., Amaranthus viridis L., Portulaca oleraceae L., Commelina bengalensis L., Trianthema portulacastrum L.
• Initial 90-120 days period of crop growth is considered as most critical period of weed competition.
• Therefore the weed management practice adopted should ensure a weed-free field condition for the first 3-4 months period.

Control measures

a. Intercropping

• Hoeing is done first by a week or so after planting in order to break the surface crust, else light irrigation is followed by the same period in order to help emergence of sprouts.
• After the sprouts are out, the hoeing by bullock drawn implements is followed to control weeds as well as for loosening surface soil.
• If the weeds are more, the hoeing is followed by hand weeding. One to two hand weeding and one hoeing are given within 6 – 8 weeks after planting by which time first top dressing of nitrogen fertilizer is given.
• Spraying of Atrazine @ 2 kg a.i./ha as pre emergence and 2,4-D sodium salt @ 1 kg a.i./ha as post emergence (8 to 10weeks after planting) control weeds effectively.

b. Intercultural Operations

Earthing up/Hilling up

• It is done in 2-3 stages.
• The first earthing up is known as “partial earthing up” and second operation is “full earthing up”.
• Partial earthing up is done after first top dressing to cover manure and to provide anchorage to the freshly developing root and shoot.
• Full earthing up is done after final manuring which is usually done at 90-120 days after planting coinciding with the peak tiller population stage.
• Earthing up at 3-4 months stage helps to check further tillering, promotes better soil aeration, provides better soil volume for root growth and prevents the crop from lodging.
• One more earthing up is done at around 6 months when a stable cane population has been achieved.

Detrashing

• All the leaves are not useful for the optimum photosynthesis, only the top 8-10 leaves are required.
• Most of the bottom leaves dry out as the crop ages.
• In fact the bottom green leaves drain out the food material which otherwise could be used for stalk growth.

• Therefore, it is important to remove dry and lower green leaves. This operation is known as detrashing. It is done manually.
• Detrashing should be taken up after the cane formation around 150 days after planting. There after it could be done at bi-monthly interval depending up on the labour availability.

The advantages of detrashing are:

• Maintaining clean field
• Enhances air movement and enriches CO² with in the crop canopy providing an ideal micro-climate for unrestricted growth of cane
• More food material is made available for stalk growth
• Reduces the problem of infestation of several insect-pests like scales, mealy bug, white flies etc
• Reduces bud sprouting due to accumulation of water inside the sheath in some varieties.
• Facilitates easy entry and movement in the field, particularly to inspect the condition of the crop and drip laterals and thus accordingly plan the fertigation and plant protection schedules
• A clean field minimizes rodents, rats, squirrels in the field which may otherwise cause damage to the crop
• Facilitates easy and economy in harvesting besides clean canes for crushing
• Detrashed trash can be used as a mulch for moisture conservation
• Clean leaves can be used for composting.

Wrapping

• It is the wrapping of the dried leaves of S/C crop around the S/C stems and is continued till the cane starts flowering or arrowing.
• About 3-4 clumps of canes are then brought together and tied.

The objectives of wrapping are:

• It minimizes lodging and also facilitates propping in regions of typhoons or heavy rains associated with heavy wind which force the crop the lodge.
• It also helps to protect the cane stem from cracking due to over sweetness and scorching.

Propping

• The operation of tying the leaves together using the bottom dry and green leaves is known as propping.
• It is primarily done to check lodging of cane.
• Usually, the trash without removing from the cane is twisted to form a sort of rope and cane stalks are tied together.
• This is known as trash-twist propping.
• Propping can be either done for each row or two rows can be brought together and tied. In areas where cane top growth is heavy and wind velocities are high, propping is very much necessary to prevent lodging.

Lodging causes several problems as;

• Cane breakage and thus loss of stalk number at harvest and thus loss of cane yield
• Infestation of certain pests and diseases causing microbes through lodged and damaged canes
• Damage by rats and rodents
• Bud sprouting leading to reduced cane quality
• Aerial root formation which also affects cane quality
• Difficulty in inspection of driplines and harvesting

Removal of water shoots

• Water shoots are the late-formed tillers or side shoots, which are robust and fast growing.
• They originate mainly due to plentiful supply of water, inadequate earthing-up and late fertigation.
• These water shoots, as the name indicates, contain lot of water and less sucrose and more of reducing sugars.
• Water shoots affects the growth of adjacent stalks.
• They harbor insect-pests and when they are harvested and sent to mill for crushing, lead to reduced juice quality and affect sugar recoveries.
• Therefore it is advisable to remove water shoots as and when they arise.
• The water shoots can be used as cattle feed.

Control of flowering

• In commercial cane production, flowering is not desirable.
• Once flowering occurs, usually, usually vegetative growth stops and cane starts ripening.
• After flowering, cane be kept in field for about 2-3 months and later on if unharvested, cane deterioration take place rapidly.
• There will be reversion of sugars, increase in fiber, pith formation, cane breakage and other such problems.
• The problem is severe when cane harvest is delayed and extends into hot summer.

The control measures are :

• Use non flowering varieties in areas where flowering is a serious problem.
• Irrigation control during the flower initiation stage.
• Changing planting dates.
• Ethrel is applied @5oo ppm twice or@1000 ppm once during flower initiation period.