Sunflower (Helianthus annuus L.) is an important crop that is cultivated throughout the world for oil and food. The sunflower seeds are either directly consumed or extracted for fuel, which is used for cooking and other purposes.
Authors: Mohsin Shafiq, Muhammad Zubair Ayyoub
Introduction
The seeds of Sunflower are rich in minerals, vitamins, and nutrients such as potassium, iron, zinc, magnesium, and selenium. The seed of sunflowers improves the brainpower, digestion, and functioning of the cardiovascular system (Organic Facts, 2019).
The crop losses occur in the supply chain from the period of pre-harvest to human consumption. Pre-harvest losses arise because of insects, rusts, and weeds before the process of harvesting starts. Harvest losses happen from starting to completion of harvesting and are caused by shattering. Postharvest injuries occur from the period of the harvest to human consumption. Postharvest includes food loss through the food supply chain from crop harvesting to its consumption. The PHL can be categorized as weight loss, nutritional loss, quality loss, seed viability loss, and economic loss. These losses include the on-farm losses when the grain is winnowed, threshed, and dried. Mostly grain losses occur in developing countries where farmers wait for a rise in prices or selling opportunities. These losses can evaluate at each step by taking some actions, and by implementing new technologies and methods, we can reduce these losses.
Where do losses occur?
Sunflower seeds can be lost at several places, and losses must be evaluated at each location to take proper action. Typically, losses occur in 3 places:
Pre-harvest Losses:
In the pre-harvest seed is lost or shed before the combine harvests the crops, these losses caused by birds, animals eating the seed, plants falling over, and heads rubbing together in the wind, which results in seeds becoming dislodged. These losses can be minimized by harvest the crop when it is fully matured and finishing on time.
Header Losses:
At combine header, few losses of seed and heads occur and are not collected into the machine, and the losses rate mainly depends on the skills of the combined driver, crop condition, and header type being used. The primary purpose of gathering heads with the least stalk entering the combine and least losses from shattering. Head of Sunflower has many seeds, so make sure they all go through the combine, which will result in the reduction of the sunflower harvest losses. Header losses can be improving by merely reducing the forward speed; having patient during harvest will pay your bills.
Combine Threshing Losses:
After gathering sunflower head into the combine, drum, concave, and sieve settings cause a lot of losses because the seed is not adequately threshed out of the leaders or sometimes permitted to pass over the back and is emitted along with trash. The essential purpose is to achieve a complete threshed head onto the straw walker in a single piece. Various combine harvesters have different optimal settings for sunflowers. The best guide is to combine at specific forward speed, well open concave, use a low airspeed, and harvest crop when seed moisture is in the little teens.
Causes of losses:
The crop undergoes many operations during its transition from farm to consumer. These operations include harvesting, threshing, cleaning, drying, storage, processing, and transportation. During these operations, the crop is lost due to various factors like insufficient processing facilities, biodegradation, and improper handling. It’s crucial to know about the supply chain and identify the factors that cause the food’s damage during this chain—here discussed those factors at different stages during the supply chain that cause food losses.
Harvesting: Inadequate supervision and carelessness results in spillage—the absence of harvesting tools for Sunflower.
Storage losses: Improper storage facilities, grain contamination, poor threshing, ground drying, and leakage cause grain spillage, while rodents attack and storage pests damage the grain and reduce their quality during the storage process. Keeping the moisture content below 10% is favorable for seed storage.
Milling losses: It includes poor pre-treatments, spillage resulting in grain contamination—proper maintenance required at this, which is not given.
Table 02: Sunflower losses at critical points: (H. Muyinza et al., 2017).
Crop | Critical point | % losses | Loss factor | Food loss storage sampled |
Sunflower | Harvesting | 2% | Spillage | Farmer |
Drying | 5% | Contamination & Spillage | Farmer | |
Storage at miller point | 35% | Mould, Aflatoxin and Spillage | Miller store’s |
Intrusion to reduce losses:
- Hermetic Bags
Hermetic bags are also known as “airtight storage” or “sealed storage,” is getting great popularity for storing seeds of different oilseed and cereal crops in developed and developing states due to the prevention of chemical pesticides. A high atmosphere of CO2 concentration is created in hermetic bags by sealing their structure. The airtight construction builds a self-reserve environment by increasing CO2 strength (O2 decrease) due to its respiration metabolism. Airtight storage is the best and effective way to reduce storage losses. Most of the developing countries adopted this storage technique because of its easy installation method, prevention from chemical use, reasonable cost, and acceptable infrastructure. The grain’s biological activities are get indicated by the concentration of CO2 present inside of the bags.
Metallic Silos Structure: A metal silo is one of the best hermetic sealed structures made with galvanized steel sheets. It’s best to store grains for a long-time by keeping rodents and insects away. In a few places, the siloes build with aluminum sheeting, which improves the appearance by preventing corrosion.
Super Grain Bags: These are the widely used waterproof and hermetic storage options. These bags are prepared by using a high-density layer of polypropylene which contains a thickness of around 78µm.
- Natural insecticides:
Natural insecticides are biodegradable, environment-friendly, and much safe for human health. Natural insecticides are effective at helping to rid the crops from harmful insects and secure enough to keep them from poisoning you and your family. Natural pesticides are often targeted insecticides; they only attack harmful insects rather than beneficial insects. These insecticides increase the life span of the crop.
- Chemical Fumigation:
Many countries used synthetic insecticides to control the pests to minimize the grains’ losses during storage. Phosphine and methyl bromide are the most common chemicals used in developing countries (Shayaa et al., 1997). Photo-Xin can control the LGB infestation in grains (if grains moisture content less than 13%). However, only licensed technicians can use Photo-Xin
Critical points for a successful Sunflower harvest:
- There is no need to wait for the crop to dry so much.
- Headers should be high to minimize the amount of stalk passing through the combine.
- At a time, make one adjustment then check losses after each change.
- Use sunflower header.
- Chains usually work well when combine have earth straps touching the ground.
- Do regular blowdown to minimize fire hazards.
When Sunflower crop is ready to harvest:
Sunflowers can be dried to permit for an earlier harvest; try the desiccant when the crop reached physiological maturity, which can be recognized when the head back has turned yellow from green, the bracts become brown, and seed moisture is around 35%. Typically, when the head back turns brown, seeds are almost ready for harvest.
Conclusion
As the losses occur from the pre-harvest to consumption stage, there is a high need to execute effective ways to reduce such losses. The states which are facing food security and hanger can reduce these risks by utilizing storage losses at ground level. Storage losses can reduce by using effective storage techniques, improved infrastructure, use of efficient storage technology, and storage practices. World food program (WFP) worked with different government and non-government organizations (NGOs) to manifest the impact of improved postharvest management practices. It is concluded that the storage period, advanced technologies, and improved methods can reduce the sunflower losses up to 98% during the supply chain.