Contingency Plan for Management of Drought Situation in cotton

Uma Nath Shukla ,Ph.D-Agronomy,BHU

Cotton being a semi xerophytic plant has some intrinsic capability to bear with drought stress even though it is susceptible to excess moisture stress (flooding) especially at the early stages of development.

Nearly 60 % of the cotton area in our country is under rainfed conditions and is regularly exposed to the vagaries of monsoon consequently resulting in poor productivity. Intermittent spells of drought are quite common during July and August followed by cessation of monsoon activity usually by the middle of September. This situation leads to non-availability of requisite moisture and concomitantly nutrients at the later stage of boll development usually in the latter part of October. The following action plan is suggested to circumvent the impact of aberrant monsoon activity.

Contingency plan for the management of late on set of monsoon/deranged monsoon activity

This year it looks as through the onset of south west monsoon has been delayed specially in central metrological region (comprising the Vidarbha of Maharashtra and, Madhya Pradesh and Gujarat ), Western metrological region ( Western Maharashra , Khandesh, Marathwada and Gujarat ) and southern metrological region (Andhra Pradesh, Karnataka and Tamil Nadu). The sowings in the north-west region were already completed and being a predominantly irrigated crop impact of monsoon may not be crucial. Situation under rainfed cotton tract is still precarious and any time during next one week, monsoon activity may set in. Under such circumstances there may not be a significant impact in respect of cotton crop. However, if the monsoon is further delayed and if sowings have to be taken up in July. There will be a decline in yield realization. The cut off date for cotton sowings in the rainfed central zone is around 10 th July.

In the event of delay in the onset of monsoon beyond 15 th July, it will be advisable for the farmers to opt for recommended short duration legumes and cereals including green gram, black gram, soybean, cowpea, jowar, bajra, instead of cotton to realize reasonably good economic returns. Cultivation of diploid cottons (as per recommendation) and short duration cotton (G. hirsutum) cultivars to the extent possible also may fit in under such situations.

Short duration varieties/hybrids suitable for drought situation across metrological regions

 

North - West Region Central Region Western Region Southern Region Punjab, Haryana, Rajasthan Vidarbha, Madhya Pradesh Western MS, Khandesh, Marathwada, Gujarat Andhra Pradesh, Karnataka, Tamil Nadu Name of the Varieties/hybrids Days Name of the Varieties/hybrids Days Name of the Varieties/hybrids Days Name of the Varieties/hybrids Days G. hirsutum HD 123 165 Vikram 160 LRA 5166 160 L 389 170 HS 182 165 JK 4 160 G.Cot.16 140 L 603 155 H 974 170 LRK 516 160 G.Cot.18 160 L 604 160 LH 1556 170         LK 861 165 F 846 170         Sahana 170 RS 810 170         MCU 7 145             MCU 5 VT 165             Surabhi 170             Sumangala 165             MCU12 150 G.arboreum LD 327 170 Jawahar Tapti 150 PA 402 165 Srisailam 150 RG 18 170 Sarvottam 150 G.Cot.15 150 DLSA 17 165     AKA 7 150 G.Cot.19 140 K 10 145             K 11 135 G.herbaceum             DB 3-12 170 Hybrids LAHH 1 150     NHH 302 170 Savitha 170 LAHH 4 170     NHB 80 170 Surya 170 Omshankar 165     H 10 150 Sruthi 150 CSHH 195 165             Desi RAJDH 7 170     G.Cot. MDH 11 140 KCH 1 150             AKDH 7 170

 

In North-western region, water has to be used judiciously. Hence, alternate furrow irrigation should be resorted to in case of water shortage. In Western Maharashtra cotton is summer sown and irrigated crop and do not merit any contingency now.

In the irrigated tracts of central, western and southern meteorological region (M.P., MS., Gujarat , AP, Karanataka and TN) alternate furrow irrigation may be resorted to for conserving irrigation water and meet the enhanced demand due to low rainfall activity .

For the management of late sown cotton (1 st of July and beyond) coupled with intermittent and terminal drought spells depending upon the pattern and quantum of rainfall activity, the following soil and crop and pest management strategies are suggested.

Recommendations for rainfed cotton tract ( Central India (MP, Chhattisgarh, Vidarbha region of MS), South Zone (Tamil Nadu, Andhra Pradesh & Karnataka) and Western Zone ( Maharashtra excluding Vidharbha region, Gujarat & North Rajasthan) and East and North-Eastern meteorological regions ( West Bengal , Orissa & Assam).

• Cotton intercropped with short duration legume crops to a large extent enables partial risk coverage to drought situations. The preferred crops are green gram, soybean and cowpea. They also act as live mulch and as per need (depending on the nature and intensity of drought) can be ploughed and can act as organic mulch for conserving soil moisture. Further, use of surface mulch such as subabul loppings etc. to cover the open area between rows is suggested to reduce evaporative losses and conserve soil moisture.
• Effective weed management is a pre requisite under drought situations. Integrated weed management strategies need to be followed.
• Harvesting of excess run off water in micro ponds and its re use to provide one or life saving irrigations for terminal stress management and yield improvement.
• Maintenance of optimum plant population
• Opting for castor, sesamum and safflower (mid rabi crop) (as per recommendations specific to the agro eco region) instead of cotton to manage severe drought situation in kharif season.
• Alternate furrow irrigation and use of micro irrigation system (wherever feasible) will be of immense help in saving irrigation water under irrigated conditions and enable higher irrigation frequency depending on the drought situation (as per need).
• In the event of late planting of cotton due to delayed onset of monsoon maintenance of higher plant population and optimum input management to the extent possible is suggested.

Contingency planning for East & North Eastern region

Varieties/hybrids suggested for this region are as follows: Orissa - Hybrids - Savitha & Bunny; Variety-MCU5-VT ; West Bengal - Variety -LRA5166

The rains received two weeks late may not lead to yield losses in a Jhum system. The cotton + green gram is grown as mixed crop planted well in advance in sandy loam soils. Timely thinning and gap filling must be completed. Rain water conservation and recycling is one alternative in Karbi Anglong district. Mid season correction crop sesamum can be grown in these soils for which seeds are kept by farmers.

Influence of drought on the incidence of insect pests and diseases

North-western region:

Aviod growing Americal cotton in orchards as it fuaours whitefly outbreaks. Grow only arboreum cotton or CLCuV resistant varieties in CLCuV hot-spot areas. Only recommended varieties/hybrids from reliable sources must be procured. Aviod growing tur, moong and bhendi in and around cotton field as these harbour insect pests. Off-season hosts must be discouraged. Weeds such as Sida sp., Abutilon sp and Xanthium sp. Must be uprooted to prevent initial build-up of spotted bollowem, whitefly and CLCuV.

Spinosad can be used against the early infestation of spotted bollworms, particularly in some parts of Punjab . Power sprayers are strongly recommended to conserve water.

Hybrids must be grown in medium-deep soils having good drainage. Apply 5-10 tonnes of well decomposed compost or FYM/ha before sowing. Delint the seed with 100 ml sulphuric acid/kg seed for two minutes, was with water and soak for two minutes in Calcium carbonate (5g/ltr water). Treat hybrid seeds with Ceresan wet or Agallol @ 1 g/ltr water, Captan or carbendazim @ 2 g/kg, imidacloprid or thiomethoxam. Early sowing on ridges and furrows, especially in areas with drip facility, could be adopted. Sowing must be completed by the third week of May. Wowing can be done at a row spacing of 67.5 cm with 30 cm palnt-plant spacing or preferably wider for varieties and 75 cm for hybrids.

Application of weedicide Stomp 30EC or Basalin @ 45 EC 2.5 lt/ha and harrow immediately to prevent degradation. Harrowing must be done twice after pre-monsoon showers and field should be leveled.

Though most of the areas are irrigated in this region, the drought situation may affect the supply of irrigation water. Whiteflies, which are the vectors of cotton leaf curl virus may pose a threat to the crop resulting in higher incidence of CLCuV. Management of whiteflies must be done through pesticidal spray.

North Eastern region:

One application of synthetic pyrethroid can be used against the early infestation of pink and spotted bollworms.

Early maturing varieties/hybrids may be preferred as they escape insect pest infestations in the region.

Arboreum cottons are prone to grey mildew and Fusarium wilt. Management of these diseases must be done with fungicidal application.

Central region:

Choice of sucking pest resistant hybrids/varieties is a pre-requisite. This helps in avoiding early insecticide sprays thus conserving water. The sucking pest resistant varieties do not wilt easily under pressure of sucking pests in drought conditions.

Cowpea as an intercrop will help in the sustenance of ladybird beetles, which will help in protecting the crop against the onslaught of sucking pests and thus preventing wilt.

Apply fertilizers considering the crop history, previous crop and its fertilizer use pattern.
Nitrogen rates recommended for G.hirsutum varieties range from 40-60 kg/ha in rainfed and 60-90 kg/ha in irrigated cotton. For hybrids, 90 kg/ha in rainfed and 100-120 kg/ha in irrigated . P and K doses depend on soil test values or in their absence N:P:K is used at a ratio of 2:1:1. Excessive nitrogen promotes pest infestation.

Avoid synthetic pyrethroids almost completely so as to prevent outbreaks of whitefly, which otherwise occur in warm and humid conditions that are characteristic of drought conditions.

Bacterial blight, fungal foliar spots and parawilt are the major diseases in this region. Long dry spells with intermittent rains may aggravate the incidence of the diseases. These should be managed with fungicidal sprays as and when required.

Western region:

Sucking pest resistant hybrids/varieties help in avoiding early insecticide sprays thus conserving water. The sucking pest resistant varieties do not wilt easily under pressure of sucking pests in drought conditions.

Cowpea as an intercrop will help in the sustenance of ladybird beetles, which will help in protecting the crop against the onslaught of sucking pests and thus preventing wilt.

Spotted bollworm can cause damage to growing points initially, hence scouting is necessary during the first two months and removal of affected parts helps in minimising future damage. De-topping can be done at 60 days after sowing to get rid of the affected growing points, containing the spotted bollworm larvae.

Avoid synthetic pyrethroids almost completely so as to prevent outbreaks of whitefly, which otherwise occur in warm and humid conditions that are characteristic of drought conditions.

Bacterial blight, grey mildew and soil borne diseases like root rot are important diseases. The strategies of management for central region may be followed.

Southern region:

Destruction of crop residues to prevent carry over of pest populations and summer ploughing to destroy resting stage insect populations. Especially useful for pink bollworm management. Immediately after the season allow animal grazing in fields and ensure timely removal and destruction of cotton stubbles, followed by deep ploughing to expose the carry-over population of bollworms. Do not stack cotton stalks near fields.

Castor crop as border rows will be useful to trap Spodoptera litura larvae. Trap crop is strongly recommended for Bt-cotton, since Bt-cotton does not afford good protection against Spodoptera spp.

Use of power sprayers should be encouraged to save water utilization. Akela pump sprayers should be discouraged completely.

Spotted bollworm can cause damage to growing points initially, hence scouting is necessary during the first two months and removal of affected parts helps in minimising future damage. De-topping can be done at 60 days after sowing to get rid of the affected growing points, containing the spotted bollworm larvae.

Handpicking of larvae 2-3 days after insecticide sprays effectively eliminates any surviving population, which can cause future resistance problems.

Alternaria leaf blight and grey mildew in Karnataka, bacterial blight and Verticillium wilt in Tamil Nadu and fungal foliar spot as well as parawilt in Andhra Pradesh are the major diseases. These diseases may appear in moderate to severe form in certain areas. Fungicidal spray/application must be resorted to wherever the disease appears.