When Should Fertilizer Be Applied To Crops
- November 1, 2021
Fertilization is not done to keep plants alive, but to make sure they grow their best.Generally speaking, the best time to fertilize landscape plants is around the time they begin to grow actively.Trees, for example, begin to wake up and grow in early spring, and typically are fertilized once in February or March.Most shrubs make active growth in the spring and early summer, so we tend to fertilize them once around March or April.Granular fertilizers are generally applied about every six to eight weeks.Dan Gill is a horticulturist with the LSU AgCente.r Have a gardening question? .
How and When to Fertilize Your Vegetable Garden
Apply fertilizer with caution, though: The only thing worse than starving a plant of nutrients is to accidentally overfertilize it.For edible crops, fertilizer is usually applied in the spring and mixed into the garden soil before planting.This ensures that there is less of a chance of the tender new growth brought about by the fertilizer getting immediately killed by frost.While a spring application is a good general rule, understand that what plants really need is help when they are growing the most.This occurs earlier for spring plantings of lettuce, arugula, kale , and other leafy greens .Tomatoes and potatoes will need extra fertilizer mid-season as the plants take up and use existing nutrients.Ornamental trees, shrubs, and perennials are often fertilized at the beginning of their growing season, as dormancy breaks.You may even find that if your garden has been fertilized for years, you have high levels of nutrients.These three numbers refer to the three most important nutrients plants need: Nitrogen (N), Phosphorus (P), and Potassium (K).If you add up the numbers, they are the percentage of the bag’s total weight (the rest is simply filler to make it easy to apply).For tomatoes, we use a separate fertlize with a 3-4-6 ration which also contains calcium to help prevent blossom-end rot.Vegetable crops require most of their nitrogen after they have made considerable growth or have already begun to fruit.Later in the season, some plants benefit from a nitrogen side dressings (sprinkled in middle of rows).Sweet corn can benefit when plants are 8 to 10 inches tall and then one week after tassels appear.These vegetables should NOT have added nitrogen: sweet potatoes, watermelons, carrots, beets, turnips, parsnips, lettuce.Processed fertilizers (also called “synthetic” or “chemical” fertilizers) are manufactured from natural ingredients such as phosphate rock (P) and sodium chloride (NaCl) and potassium chloride ( KC l) salts, but these are refined to be made more concentrated.Organic fertilizers are materials derived from plants that slowly release nutrients as the micro-organisms in the soil break down.(Plus, they don’t leach into and pollute waterways, as do many of the synthetic, water-soluble fertilizers, which plants can’t fully absorb.).While most organic fertilizers are slow-release products, some release a portion of their nutrients quickly (examples are animal manure, biosolids, and fish emulsion).During the growing season, lighter supplemental applications can be made to the top inch of soil in crop rows and perennial beds and around the drip lines of trees or shrubs.No matter how carefully you remove plants from their containers and place them in the ground, some root hairs will break.The fertilizer will reach the roots immediately and enter them at the broken points, potentially “burning” them and causing further die-back.Also, take care that the fertilizer is indeed diluted based on instructions, or you could burn the leaves.If you have more questions about fertilizers, please ask below, or we encourage gardeners to call their country’s free cooperative extension office for local advice. .
Index Suggests That Half of Nitrogen Applied to Crops Is Lost
Whereas the global average shows a decline, nitrogen fertilizing has become more efficient in developed economies thanks to technologies and regulations, and new results out last month from the University of Minnesota as well as field trials by the International Fertilizer Development Center are just two examples of ongoing research to limit nitrogen pollution without jeopardizing yield.Yet nitrogen applied to crops often ends up elsewhere.Fertilizer placed away from a plant’s roots means that some nitrogen gets washed away or converts into a gas before the plant can use it.Fertilizer applied at an inopportune moment in a plant’s growth cycle goes to waste.In many parts of the world, cheap subsidized fertilizer is critical for producing enough food.And according to plant scientist Rajiv Khosla at Colorado State University, who studies precision agriculture, farmers struggle to apply just the right amount of fertilizer probably 90% of the time.According to an average of 13 global databases from 10 data sources, in 2010, 161 teragrams of nitrogen were applied to agricultural crops, but only 73 teragrams of nitrogen made it to the harvested crop.The new research was published in the journal Nature Food in July.Globally, nitrogen use efficiency is 46%, but the ratio should be much closer to 100%, said environmental scientist Xin Zhang at the University of Maryland, who led the latest study.The crops with the lowest nitrogen efficiency are fruits and vegetables, at around 14%, said Zhang.The United States has similarly cut losses by improving management and technology.The method buries cheap nitrogen fertilizer into the soil, which feeds nitrogen directly into a plant and reduces losses. .
Three prime chemical elements are found in all mixed fertilizers:.Each soil type has its own mix of nutritional ingredients, so before considering what fertilizers a plant may require, we need to consider the soil in which a plant is growing.When it comes to fertilizing, more does not mean better.This method gives plants food while you water.This approach is similar to base application, but the water is applied to the leaves rather than to the soil.If you want to green up your lawn, choose a mix like 25-6-4, which is high in nitrogen.For flower and fruit development, bonemeal with a high phosphorus count is the organic of choice, while blood meal is a good source of nitrogen.Since they must be broken down by water before a plant can use them, granular fertilizers do not leach out of the soil as rapidly as water-soluble types.Both types of fertilizers are effective, so the one you choose depends on whether you want to give your plants a quick but frequent fix or a sluggish but extended feeding.There are several ways to apply granular and water-soluble fertilizers, but there are a few general guidelines that one should follow when applying them.Never apply a granular fertilizer when the soil is extremely dry, and water it in thoroughly after applying to prevent plant burn.When to fertilize. .
Should you apply fertilizer for cover crops?
One reason many people try cover crops is to attempt to capture nitrogen left behind after the growing season.This information was prepared by the Indiana Conservation Partnership, led by Natural Resources Conservation Service personnel including Don Donovan and Clint Harrison, district conservationists; Kris Vance, public affairs specialist; Victor Shelton, state agronomist/grazing specialist; Tony Bailey, state conservation agronomist; and Shannon Zezula, state resource conservationist.Is there value in spending money to apply commercial fertilizer to a cover crop in times of narrow profit margins?If water quality isn’t a concern and you’re trying to improve your soil organic matter levels with high-carbon cover crops, it’s important that they get off to a good start in the spring coming out of dormancy.Another option is to include a legume such as crimson clover in your cover crop mix, even if you’re not planting corn next, Donovan says.Should manure not be available or you don’t wish to include a legume, provide some nitrogen by applying phosphate for next year’s crop needs near cereal rye seeding time. .
Why do plants need fertilizers?
When crops are harvested, important nutrients are removed from the soil, because they follow the crop and end up at the dinner table.The soil feeds the plants.The three most common mineral fertilizers are those based on nitrogen, phosphorus and potassium.73% of the soils are deficient in phosphorus, whereas 55% lack potassium.What is fertilizer used for?Different crops remove different amounts of nutrients from the soil.The amounts of nutrients in organic fertilizers vary and are much less concentrated than those in mineral fertilizers.Mineral fertilizers reduce the amount needed and the number of vehicles to transport the fertilizing products.The same happens if we eat animals who have eaten plants with the same nutrients. .
Yes, You Really Do Need to Fertilize Your Plants
Once you factor in the different types of fertilizers, the quality of your soil, and what exactly your individual plants need, sometimes it feels easier to just skip the whole process.Besides sunlight and water, all plants require certain nutrients to thrive, and if you don’t occasionally replenish their supply, they can end up having health issues.Without enough of these macronutrients, you'll eventually end up with very sad plants that have weak stems, smaller leaves, fewer flowers, and poor color.And for newer properties that have had fill dirt added after construction, your yard might actually start out with very poor soil that's low in organic matter, which is the main natural source of plant nutrients.Adding compost, mulch, and other organic matter to your soil helps make it richer, but may not provide nutrients fast enough for everything you're growing.This is one reason why it's important to start with a quality potting soil, which often will already have some slow-release fertilizer mixed in to support your plants' initial growth.If you use a liquid fertilizer that's meant to be mixed with water first, a handy trick is to dilute it to about half the strength the label calls for.These tend to be species that grow fast and bloom a lot, including most annuals, fruits, veggies, roses, and hydrangeas.Others, including some perennials (such as bee balm and coneflower), trees, and shrubs, don’t need much fertilizer at all, especially if you add plenty of compost or other organic material to your soil before planting. .
Fertilizer applications may in many cases be much reduced, either because present usage is more than is necessary or because at least part of the nutrient additives can come from organic, rather than inorganic, sources.For example, the amount of nitrogen now applied to an acre of corn by way of inorganic fertilizers could be supplied by the annual manure produced by one dairy cow, or two young fattening beef cattle, or nine hogs, or 84 chickens .U.S. livestock manure production is estimated at 1.7 billion tons per year, and more than half of it is produced in feedlots and confinement rearing.It is also possible to plant legumes between corn rows in late August and plow this green manure under in early spring.It is estimated that increased efficiency in the manufacture and use of pesticides would conserve 12 trillion BTU (the equivalent of 2.1 million bbl of oil) per year.If 50 million acres of corn were to be treated once with herbicide, a saving of 3.5 trillion BTU (the equivalent of 602,000 bbl of oil) would be effected if the application were done without machinery (although the manpower requirements would be huge). .
Fall or Spring Fertilizer Application
In addition, when more nitrogen is applied then a higher percentage of the nutrient will be lost if uncooperative weather (too much moisture) is present.Vetsch said some western Minnesota farmers apply urea in the fall for a source of nitrogen come spring as this part of the state tends to be drier and the nutrient is not lost.Kaiser said for P, a soil test with 20 to 25 parts per million (ppm) is a decent level and in most situations applying more P at this point would not produce a yield increase.Vetsch said with much of the farm land rented in the state of Minnesota, many farmers choose to apply a more maintenance level of P in the soil.Kaiser and Vetsch agreed that K is frequently an overlooked nutrient as many soils in the region are often high in K levels. .