Shunt out the Karnal bunt
Bipan Sharma
KARNAL bunt, caused by Neovossia (Tilletia) indica, occurs sporadically in epidemic proportions in certain years and causes substantial losses. It continues to be a potential threat to production and trade of wheat. Moreover, the disease is a major bottleneck in wheat export, as the importing countries insist on Karnal bunt-free grains.

Good upbringing is essential for later health
S.S. Kukal and D.S. Benipal
WHEAT is a premier cereal with an average yield of 43.2 quintals per hectare. The growth stages of the wheat plant comprise pre-establishment, vegetative and post-anthesis (reproductive).

Cut losses in harvester 
S.S. Ahuja and Pramod Rikhi
DURING every paddy procurement season there is hue and cry regarding excessive "crackage" in combine-harvested paddy grains. This may be because of a lack of training of combine operators. This leads to poorer returns for the farmer. Crop variety is also an important reason for this problem.

TREE TALK
Shahtoot for fruit and timber
K.L. Noatay
SHAHTOOT is an interesting plant. A middle-sized deciduous tree, its English name is Mulberry and the scientific name Morus alba. The genus has a few other sibling species like M. serrata, M. indica, M. laevigata, etc. Its local names are toot, tul, tulklu, chinni, chun, tunt, tutri, tun, etc. There are two main varieties of the plant: one that bears black fruit and the other white.

Grow wheat on raised beds
Better yield; less input; weed control; intercropping
Sukhraj Singh Dhillon

THE conventional (flat) system of planting and flood irrigation for wheat leads to several problems like excessive downward leaching of plant nutrients, poor aeration and high impedance from soil to growing plant roots. Water is a valuable input and so are fertilisers and weedicides, which are expensive and environmentally unsafe. Thus, lesser and safer use of these inputs is essential.

Wheat is mostly planted through drill or as broadcast and these methods make split application of N fertiliser impossible in a young wheat crop. Certain weed species, particularly Phalaris minor (gulli danda), show resistance to certain herbicides and the cost involved in newer herbicides is very high. There are two major concerns: efficient use of costly inputs and sustaining productivity without harming the environment.

To find a better alternative technique, research on raising wheat on beds was initiated in the Department of Plant Breeding, PAU, with the development of a bed planter in 1995, which was later suitably modified for intercultivation-cum-fertiliser placement in young standing crops on beds.

The new practice of sowing timely wheat in medium to heavy soils on raised beds and irrigation application in furrows has shown promise in achieving efficient use of inputs with comparable to better (3-4%) yield. Sowing wheat on beds is now possible with the development of a bed planter, which makes possible two wheat rows—20 cm apart, 37.5 cm-wide bed, and 30 cm-wide furrow between two beds. An adjustment in these distances is also possible with this planter. A seed rate of 30kg/ acre for bed-planted wheat gives a yield similar to 40kg/ acre under conventional (flat) planting.

On an equal area basis, the depth of irrigation in bed-planted wheat is 5.0 cm as compared to 7.5 cm under conventionally sown wheat. Bed planting helps use fertiliser better because the chances of retaining the basal dose of applied fertiliser in the bed are better, where plant roots are concentrated more. The second dose of N fertiliser is also drilled within beds. Also, weed emergence and their control on beds and in furrows is also possible through inter-cultivation (with tractor) or integrated control of weeds.

The new technology of growing wheat on raised beds has been recommended by the university as a package of practice.

The bed planting system would help in giving comparable to better yield in medium to heavy soils by lesser but more efficient use of inputs like water and fertiliser, seed and weedicide.

Mechanical interculture/ integrated control of weeds in both beds and furrows in this system of planting would help reduce the dependence on costly herbicides. Also, the handpicking of left over Phalaris minor plants is easier in bed planted wheat. Continuous use of mechanical interculture for four to five years and handpicking of weeds may ultimately eliminate the Phalaris minor menace.

Diversification through intercropping of sugarcane/ mentha, while the wheat is on beds, could be another advantage. Preliminary research findings on growing wheat, maize, soybean and even rice on permanent (renovated) beds has shown encouraging results. Thus, the use of permanent beds would help reduce tillage costs and green house gas emissions from burning diesel and the stubble retention system would also reduce the loss of soil organic matter.

Shunt out the Karnal bunt
Bipan Sharma

KARNAL bunt, caused by Neovossia (Tilletia) indica, occurs sporadically in epidemic proportions in certain years and causes substantial losses. It continues to be a potential threat to production and trade of wheat. Moreover, the disease is a major bottleneck in wheat export, as the importing countries insist on Karnal bunt-free grains.

The disease causes quantitative losses in yield and seed vigour, quality, and germination and leads to toxicity.

Karnal bunt becomes evident on maturity. Affected grains are converted into black powdery mass enclosed by the pericarp. The bunted grains are irregularly distributed in the ear. It implies that they are the result of airborne, localised infection. The disease spore mass remains covered by the pericarp for some time but later ruptures, exposing the black powder to air. A foul smell due to the production of a volatile substance trimethyleamine is prominent in this disease.

The present-day wheat cultivars lack immunity/ high resistance to Karnal bunt. The pathogen survives through seed and soil borne teliospores and infection occurs through airborne sporidia. Hence, successful management of this disease may be achieved through integration of host resistance, regulatory measures, cultural practices, bio-suppression techniques and chemical measures into a practicable system. Adoption of various cultural practices, use of fungicides against seed and soil-borne inoculum and cultivation of disease-resistant varieties are three major approaches to combat this disease.

The following practices may be adopted for effective control of the disease:

• Crop rotation for long period

• Select disease-free seed and treat it with Bavistin or Vitavax (2.5 g/ kg seed) to check seed-borne inoculum

• Use only resistant varieties in disease-prone areas.

• Judicious use of nitrogenous fertilisers

• Irrigation should be avoided at the time of heading.

• Single spray of Propiconazole (Tilt 25 EC) @ 500 ml/ha at heading stage of crop growth is very effective.

Good upbringing is essential for later health
S.S. Kukal and D.S. Benipal

WHEAT is a premier cereal with an average yield of 43.2 quintals per hectare. The growth stages of the wheat plant comprise pre-establishment, vegetative and post-anthesis (reproductive). The number of days taken to complete each stage is a varietal characteristic, but may be influenced by other factors like temperature, day length, fertilisers, diseases, etc. With the emergence of coleoptiles of germinating seeds above the soil surface, young plants start establishing the root system and undergo one-leaf, two-leaf, three-leaf and four-leaf stages, which comprise the seedling stage.

Seedlings, being very delicate and with not so much established root system, are often subject to various disorders, the most common being the yellowing of leaves. A general yellowing of the leaves of the seedlings, especially starting from the tips and along the edges, takes place. Later on necrotic areas develop within the chlorotic tissue and stunting and general decline of plant growth starts. This yellowing during the initial stages may be due to any one of the following reasons:

Deficiency of various nutrients, mainly nitrogen, sulphur, zinc and manganese, results in discolouration of leaves of the seedlings. However, each nutrient has specific deficiency symptoms, which are easily recognisable.

Nitrogen: In nitrogen deficient plants, older leaves become light green to pale yellow, especially from the tips towards the base in a V-shaped pattern. This is followed by drying or dropping of older leaves. This results in fewer tillers and smaller cobs/ears, thus reducing the yield.

Sulphur: Unlike nitrogen, sulphur deficiency appears on younger leaves, which turn yellowish green or chlorotic, leaving the tip slightly green. The older leaves remain green for longer periods. Under severe deficiency, all leaves may become yellow, resulting in stunted growth. It is most common in light-textured soils, which are irrigated mainly by canal water, or when the rains occur during early growth stages.

Zinc: Plants growing in sandy soil, low in organic matter and alkaline in nature, are prone to this deficiency. The third and fourth leaves from the top develop a band of white or yellow tissue in the middle. This is followed by inter-veinal chlorotic mottling and a white to brown chlorotic region in the middle leaf. The necrotic areas later on intensify and coalesce, resulting in the collapse of the affected leaf near its middle. This results in bushy growth of the plant and delays earing and maturity.

Manganese: The symptoms of this deficiency appear a few days after the first irrigation. The older and middle leaves at the basal part exhibit inter-veinal chlorosis, which later extends towards the tip. Under mild deficiency, very light greyish yellow to greyish-brown specks of minute size appear in the inter-veinal chlorotic regions. Under severe deficiency, these specks enlarge and coalesce to form a streak or a band of pinkish-brown or buff colour in between the veins, which remain green. It leads to stunted growth and a weak and restricted root system.

Bad weather, like continuously cloudy days, leads to yellowing of wheat seedlings due to decreased photosynthetic activity.

Due to very low temperatures at night, young seedlings often get injured by frost and turn yellow, affecting growth.

In paddy soils, wheat plants show symptoms of nitrogen deficiency after first irrigation. This might happen despite applying sufficient nitrogen. It is due to stagnation of water in the root zone of the soil because of the presence of a hard layer at 15-20 cm depth, leading to poor aeration of the root zone. The roots are not able to respire properly under such conditions and, thus, do not have sufficient energy for nitrogen uptake.

In coarse-textured soils, apply 100 kg gypsum per acre before sowing as a preventive measure, especially in soils where phosphorus is applied through diammonium phosphate (DAP) for correcting sulphur deficiency; same amount of gypsum may be applied, followed by hoeing. Single superphosphate may be preferred as a source of phosphorus in soils where deficiency of sulphur has been observed during previous years.

For correcting zinc deficiency, apply 25 kg of zinc sulphate per acre for 2 to 3 years. It can also be corrected in a standing crop by spraying 0.5 per cent zinc sulphate solution twice at 15 days’ interval. The solution for spray can be prepared by dissolving 1 kg zinc sulphate and 0.5 kg unslaked lime in 200 litres of water for an acre of the crop.

Manganese deficiency can be corrected by foliar application of manganese sulphate solution thrice at an interval of one week on sunny days. In areas where manganese deficiency is a perpetual problem, give one foliar spray of 0.5 per cent manganese sulphate solution two days before the first irrigation and the remaining two at weekly intervals. In soils deficient in manganese, or light-textured soils, avoid growing wheat varieties like PBW-34, PBW-125, PBW-222.

For protecting young seedlings from frost injury, give light irrigation to the crop during the period of continuous frost.

In soils with aeration stress, the crop may be sprayed with 3 per cent solution of urea (9 kg urea dissolved in 300 litres of water for one acre). For preventive measures, the field plots should be made smaller. Also, light and frequent irrigation is better. Paddy soils should be deep tilled to break the hard layer.

Cut losses in harvester 
S.S. Ahuja and Pramod Rikhi

DURING every paddy procurement season there is hue and cry regarding excessive "crackage" in combine-harvested paddy grains. This may be because of a lack of training of combine operators. This leads to poorer returns for the farmer. Crop variety is also an important reason for this problem. Difference in varieties and the sowing date result in different dates of maturity. Grain losses also vary due to changes in temperature and humidity between morning and evening, requiring readjustments. But most operators ignore these important aspects.

Given below are certain problems with their solutions:

—Cutter bar too high

—Reel speed or height not proper—higher reel speed causes shattering of seeds and unthreshed heads, particularly if too dry; setting reel too high will fail to lay crop on platform; setting too low will throw cut straw; reel slat too narrow will increase shattering losses

—Poor condition of crop divider, cutterbar, blades and guards

—Cylinder speed too low

—Cylinder concave clearance too much

—Concave length inadequate

—Misalignment or damaged cylinder and concave bars/teeth

—Crop heavy or travel speed too high

—Crop too damp

—Rack speed too high

—Straw chopped too fine

—Straw rack opening clogged with green material

—Rack overloaded due to excessive feeding

—Blower blast too high or not properly directed

—Straw chopped too fine, causing sieve overloading

—Sieve opening clogged with green material

—Sieve opening not enough or too sloppy

—Too much threshed grain struck in tailing

—Cylinder speed too high

—Cylinder concave clearance too little

—Misalignment/ bent cylinder concave teeth/ bars

—Threshed grain returning for rethreshing

—Misalignment of concave and cylinder due to end play

—Sieve opening too large

—Air blast too low or not properly directed

—Sieves overloaded due to too heavy feed, too finely chopped straw or sieve speed too slow

—Excessive weeds or crop moist

It is important to clean the combine properly after use, otherwise stuck mud, straw, etc., can cause rotting. Open all inspection windows of the combine, run it idle for 5-10 minutes to shake loose the stuck debris, stop the combine, and use high air/ water pressure to clean debris.

TREE TALK
Shahtoot for fruit and timber
K.L. Noatay

SHAHTOOT is an interesting plant. A middle-sized deciduous tree, its English name is Mulberry and the scientific name Morus alba. The genus has a few other sibling species like M. serrata, M. indica, M. laevigata, etc. Its local names are toot, tul, tulklu, chinni, chun, tunt, tutri, tun, etc. There are two main varieties of the plant: one that bears black fruit and the other white.

Habitat wise, shahtoot is quite common in lower and outer Himalayas from Kashmir to Sikkim. It is also found in abundance in the Indo-Gangetic plains from Punjab to West Bengal and parts of the Deccan plateau as well.

The bark of shahtoot is brown and rough with vertical fissures. The shahtoot leaf resembles the pan leaf — ovate in outline, serrated on the margin, often deeply incised and quite variable in size. The tree flowers during March-April and the inflorescence is generally green. Male and female flowers are borne on the same plant simultaneously.

Shahtoot fruits during June-July. The berry of the black variety is 10 to 15 mm thick and 20 to 30 mm long and globose in shape. The one of white variety is 4 to 6 mm in diameter, 30 to 40 mm in length and cylindrical in shape. These are delicious and are devoured greedily by birds, wild animals as also human beings, especially children. The fruit is also used for making juice(s) and jams.

Irrespective of their colour, the berries taste sweet, though the black ones are slightly acrid while the white are somewhat sweeter.

As per experts practising ayurvedic and or Unani systems of medicine, the shahtoot fruit is appetising and moderating for digestion, a reliever of constipation, purifier of blood and soothes throat troubles, etc. The root bark is useful in eradication of worms.

Shahtoot is a fast growing species. Its wild variety attains 30 to 50 cm diameter and 20 to 35 m height in about 30 to 40 years, when it is considered mature. Its wood is hard—while the sapwood is white, the heartwood is golden yellow. It weighs about 20-25 kg to a cubic foot and displays beautiful greyish brown streaks in between because of the annual rings. This wood takes good planing and polish, showing exquisite grain.

This timber, though not available in substantial size, is yet used for house construction works, carving out toys, sports goods like hockey sticks, expensive furniture, agriculture implements, etc. Young branches, being supple and straight, are used to make baskets (tokra). The tree serves as a shady avenue plant too.

Shahtoot regenerates itself naturally and abundantly from seeds dispersed by birds and animals. Its seedlings can also be raised by sowing seeds in a well-worked nursery. One-year-old seedlings can be transplanted during winter rains and or monsoon. Prized varieties are raised by grafting. Sericulturists and horticulturists raise the essential nursery stock by planting cuttings in nursery beds. The plant prefers sandy-loam soil with a lot of moisture.