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We conduct research and disseminate information on best management practices for tobacco production through the following activities:

• Crop management, curing and handling advisory service.
• Providing quality assurance commercial seedling production, through optimization of soilless media (float tray system), fertilization programs and cultural practices.
• Crop area/yield assessments through remote sensing.
• Research on efficient tillage systems.
• Pesticides Approval Scheme Service through testing herbicides, suckercides and growth regulators.
• Irrigation systems research.
• Research in conservation agriculture.
Recently there has been an outbreak of Striga gesneriodes in Chegutu and past reports from Mvuma has warranted renewed research efforts to curb this potentially devastating weed.


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Seed enhancement to maximize germination and seedling recovery in the float tray system.

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Compaction causes stunting of seedlings in the float tray system. From left is a seedling from the most compacted tray, and the far right is optimal compaction. Seedlings are of the same chronological age.

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An ideal float tray seedling.

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Good tillage pays, it does not cost. Tobacco does not grow well in waterlogged soils; good ridges ensure good soil drainage, and maximum yields and quality.

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Good and uniform field establishment is the key to excellent yields. Plant with enough water, use cutworm and aphid control chemicals at planting, apply basal (before, at or after planting) and top dressing (at 4 and 8 weeks after planting) fertilizers on time, use pre-emergent herbicides (before, at or just after planting).

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Striga outbreaks have been reported in Chegutu and Mvuma. Watch out for this potentially devastating weed. Report any cases to the Tobacco Research Board.

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Weeds compete with your crop for soil moisture, light and nutrients. Control weeds using pre- and post-emergent herbicides. Minimize manual weeding since it destroys your ridges. Harvesting can also be disrupted by weed growth as it is difficult to walk between the ridges. Above is nutsedge before the application of a post-emergence herbicide.

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A clean row after a post-emergence herbicide application (same field as above) to eradicate nutsedge.

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A scorched and dying weed (nutsedge) after a post-emergence herbicide application.

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Dying weeds after Clomazone (pre-emergence herbicide) application.

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Herbicide phytotoxicity on tobacco plants. This is normally caused by wrong application methods or using an overdose of the chemical.

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Always reap ripe as it is not economic to harvest overripe tobacco (above) because some of the leaf weight has been lost, and curing management can be difficult.
We conduct research in soil fertility and water quality management. The group is tasked with identifying edaphic conditions favourable to plant growth, nutrient application methods and soil conservation techniques through comprehensive research and also providing advisory services.

Research:
• Crop rotation trials are conducted to develop techniques to maintain soil fertility, conserve moisture and manage pests and diseases
• Nutritional requirements for seedling production
• Fertilizer requirements for new varieties to attain optimum yields and quality
• Evaluation of farmer practices e.g. manure application in tobacco production
• Contract research on fertilizers e.g. foliar products and soil fertility ameliorants, such as soil conditioners, and new fertilizer formulations to ensure that the efficacy data is consistent with the registered standard.

Advisory services:
1. A soil or water test report is not particularly useful unless it can be interpreted in conjunction with a whole range of factors. We therefore maintain excellency in interpretation of soil test results and subsequent site specific lime and fertilizer recommendations for tobacco and other agricultural crops. Furthermore, crop nutrition management advisory is offered. Recommendations are also provided for suitability of water for use in tobacco irrigation.
2. For growers who have adopted the tobacco float seedling production system, we offer efficient recommendations on Gromix optimum usage. Our laboratory has the capacity for solution analysis (float water) and media, which provides information on several parameters important to uniform seedling growth such as pH and EC (soluble salts). In addition we give recommendations on corrective action for pH and fertilization for the production of ideal seedlings.

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A Katambora Rhodes (Chloris gayana) grass rotation crop. The TRB has a new variety of Katambora called GHR1 which can be used to suppress nematode populations in tobacco rotations. The grass is also suitable for hay and will add the much needed organic matter to the soil when ploughed under. Seed for multiplication on farms will be available in limited quantities in the near future.

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Sunhemp (Crotalaria juncea) is an important rotation crop in tobacco lands. Besides suppressing nematode populations, it’s a useful fodder and green manure crop.


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A soil auger or spade can be used for soil sampling. Sampling soil and getting it tested is essential for growers to maximize yields and quality by applying the recommended lime and fertilizer rates appropriate for that particular land and season.

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The Z-soil sampling scheme The laboratory acts as a nerve centre for soil nutrient management as it offers services for the determination of plant available nutrients for fertilizer recommendations. Soil tests measure available nutrients in the soil and serve as the best guide to profitable use of commercial liming and fertilizing materials. Without a sound soil testing program, crop yield and quality potential may not be attained and low crop productivity can result from lack of liming and also, over or under fertilization. Internationally accepted extraction methods are employed for the determination of both micronutrients and macronutrients. Soil sampling can be done using a soil auger or spade. Sampling protocols in Shona and English are available for downloading in the downloads section
The objective is to enhance tobacco productivity through the understanding of plant physiological functions and how best to manipulate them to attain optimum yields and quality. Activities include research and development of new technologies to improve plant growth from seedling, vegetative to reproductive stages. The use of plant hormones and growth regulators is also explored.

Activities
• Research on enhancing pollen storage and viability.
• Developing pollen productivity strategies.
• Seed physiology research to maximise seed germination and seedling recovery in the float system.
• Exploring factors that influence seedling growth and survival, e.g. light, temperature etc.
• Use of plant hormones and growth regulators in improving tobacco yield and quality.
• Study of interactions between tobacco and the environment (seasonal effects on yield and quality).
Recently, we have embarked on research projects to support our Seed Production Division to optimize seed yields and quality in an effort to ensure adequate seed supply to growers.