Why localize fertilizer?
Burying the fertilizer in the soil gives numerous agronomic and environmental advantages compared to spraying onto the surface:
- No loss by volatilization
- The fertilizer is brought as closely as possible to roots
- Give precisely what the plant needs
- Avoid burning the leaves
- Decrease the quantity of necessary fertilizer
The localization of fertilizer can be made at the three stages of cultivation:
- In the passage of strip-till, before the sowing
- While drilling: the most common are the “starter” fertilization placed during the corn drilling. In no-till, it is interesting to localize fertilizer when drilling cereal or colza
- In inter-row during the vegetation for on-line cultivations. It is use historically in regions of corn production (Alsace, Landes, Pyrénées Atlantiques)
Localization with the Strip-till
When in the spring you can work deep in the soil with the strip-till, you can take advantage of it to localize big quantities of fertilizer, nitrogen especially. As with strip-till the work of the soil is reduced to minimum, the speed of mineralization is lower and more natural, thus a little later.
Burying the fertilizer with the strip-till allows the availability of elements for the plant and not for the residues of the surface which would take a part of the nitrogen to decompose it-self (in case it would be brought evenly.
With strip-till, it is necessary either to bury the nitrogen with the strip-till, or to anticipate the input.
Nitrogen localized with the strip-till corresponds to a part of the fertilization made in vegetation (in urea for example) in a classic process. The buried part represents generally ½ to 2/3 of the total dose of nitrogen.
In dry situation, not irrigated, spraying evenly can take time to be effective because of the lack of water. The burying allows, to ensure the availability of the nitrogen even without rain.
In some cases the best efficiency of buried nitrogen allows to remove ceilings on the yields, in others cases it permit to decrease the total input quantity.
The localization of fertilizer deep in the soil with the strip-till does not represent particular agronomic interest according to American studies on well provided soils. The advantage of this practice is rather in term of logistic order: while using the strip-till, localizing the fertilizer at the same is more logical.
Lime – Magnesia – …
The localization of these elements is interesting because it allows a regular maintenance of the lands where it would be good “to lime” but where it is not essential. As a matter of fact we do not see an immediate effect on the yield as for the nitrogen for example.
Actually, we sometimes hesitate to invest in a spraying of 150 € the ha. If you take the decision to localize every year a little, the cost is amortized, it allows to maintain the soil fertile, and have a boost effect on the row.
No study has been focusing on this effect. It is simply an idea of common sense, applied successfully currently, on Cyrille’s exploitation.
Localization while sowing
With a monoseed drill
A fertilizer starter contains a small quantity of nitrogen ( N ), of phosphor ( P ), and possibly of potassium hydroxide ( K ) and other trace elements as the sulfur (s), the zinc ( Zn), etc. For example : 18-46, 14-48 or micro-granulated fertilizer as Nutrifast, Physiostart, Microstar …
Localized close to the seed, the fertilizer favors strong start-up of the cultivation and accelerates the development. This confers a better resistance of the plant when facing climatic hazards (cold grounds) and faunal pests.
The starter fertilization is recommended in every case where the growth of roots risks to be slowed down, as in a cold ground, in case of excess of water or in the presence of pests in the ground such as click beetles. Thanks to an early development, placing the fertilizer as closely as possible to the roots also improve the competition with adventitious. (Dwayne Beck, Dakota Lakes Research Farm)
Localization of the fertilizer
The fertilizer can be placed in the line of sowing or either moved by 5cm. The choice of the localization of the fertilization depends on its salinity and on the texture of the soil (sandy or not). The salinity of the fertilizer is function of its concentration of N, P and S.
Example of the quantity of fertilizer 10-34 which it is possible to locate for rows spaced out of 76cm (Pioneer source):
|Localisation||Sandy soil||not sandy|
|In the row||50L/ha||50L/ha|
|1cm from row||90L/ha||90L/ha|
|2,5 cm from row||190L/ha||380L/ha|
|5 cm or more from row||+190L/ha||+380L/ha|
Microgranulated fertilizers must be directly placed in the line of sowing.
With strip-till or no-till, a fertilization starter localized in the drill must be systematically used. A colder soil and a higher faunal pests pressure can easily validate the gain of vigour obtained with the fertilization starter.
Profits of the starter fertilization in corn
According to Arvalis: ” the yield benefit is not systematic but reaches an average 2,5 q / ha. An average gains of a point of humidity is observed every time, allowing an early harvest. ”
The situations where the starter fertilization gives a yield benefit are:
- the early sowing
- the cold ground
- soils with low P and K content
- in case of no-till
- in case of known presence of soils pests (click beetles, scutigerelles, etc.)
Nitrogenous fertilization in the sowing
In no-till, to face a later mineralization which can provoque a lack of nitrogen in the first part of corn cycle, numerous farmers spread the fertilizer evenly several days before the sowing of the corn. Another solution is to localize this fertilizer during the sowing, besides the starter fertilization.
Accordingly the fertilizer must be placed at 8-10cm of the row at seed depth to avoid any risk of burn.
According to the American “No-Tiller”, by comparison with a spraying on the surface of the soil, the localization of nitrogen with the seed drill allows to save up to 20 – 25 % of the fertilizer.
For sugar beets, the localization in the sowing concerns only the nitrogen, usually brought evenly.
The main advantage is the economy from 10 to 20 % of fertilizer, thanks to the cut of losses by volatilization (estimated between 5 to 25kg / ha depending the dose and the conditions of the soil).
The nitrate fertilizer must be localized at 7cm of the seed, and has to exceed seed depth.
If the main advantage is the economy of fertilizer we notice at the same an increase of 1 to 2 % of yield.
The nitrogen localization in the sowing of beets was widely studied by the ITB and put into practice with positive results in every beets regions.
In the case of very low nitrogenous remainders or soil poor in phosphor, a small input quantity in the line of sowing favors the air growth and root development of colza in autumn. The obained vigour allows to resist against the autumn pests (slugs, altises, bud weevils). This input can be realized with a fertilizer N+P ( 18-46 ) at 50kg / ha.
This practice is very wide-spread strip-till. Many trials show an advantage in yield which results from the homogeneity of the cultivation and from the important root system development in strip-till technique.
With a seed drill for cereal
In no-till or in very simplified soil work for cereal, the localization of the fertilizer can be oraganised in several manners according to the available machines
- with the seed in the furrow
- between the lines of seed
- placed above the line
- close by and below the seed
Traditionally the localization of fertilizer during the sowing of these cultures does not seem essential. With no-till however, in case of a previous corn grain or an important vegetation cover, then remainders are low and a moderate contribution of nitrogen and/or phosphor allows a “boost” for the cultivation start-up. It permit to resist the pests better, and to develop quickly an performing root system.
With spring barley the technique is widely used in the northern countries of Europe and it has been tested by Arvalis in Loiret for several years.
With a relatively short cycle, the culture can be quickly penalized by a spring drought which would decrease the availability of the nitrogen. Burying the nitrogen allows to limit the losses by volatilization and to localize some phosphor allows to bring it as closely as possible to the roots. Except in land very poor with phosphor, the tests doesn’t prove benefits in localizing it.
On 6 tests realized between 1996 and 2012 by Arvalis in Loiret and Meurthe-et-Moselle, the localization of nitrogen did allow a gain of 2,9qx for the same dose of fertilizer. The yield gains vary according to the weather conditions of the year. Dry years are better for incorporated localized fertiliser.
Localization in vegetation inter-row
The localization in vegetation is the most economic and the most ecological way of fertilizing the on-line cultivation.
Decrease the losses by volatilization
- Improving the efficiency of the urea and the nitrogenous solution
In good conditions of use, the efficiency of the absorbed nitrogen is comparable for the various forms of nitrate fertilizer. However, the urea and the liquid nitrogen are strongly sensitive to losses by volatilization. These losses are even more important in sandy soils or with weak CCE (Cationique Capacity of Exchange). To limit these losses and obtain an equivalent efficiency to that of ammonium nitrate, the urea and the liquid nitrogen must be buried in the soil so that the ammoniac which gets free is fixed before reaching the surface of the ground. Hoeing just after a surface spraying is not sufficient to reduce losses by volatilization.
- The just return on investment
Burying nitrate fertilizers decrease from 6 to 28 % the lost quantity of nitrogen! The volatilization is even more important in dry conditions with wind: if it is not raining 15-20mm in the 10 days after the application of urea, 30 % of the input can be lost by volatilization. With urea, deep input allows an earnings of yield of 10qx compared to a contribution in height. Other tries show an advantage of 8 % yield compared with spraying evenly the surface or localized with drop hoses.
- Operating regardless of weather conditions
Nitrogen is buried in a fresh soil, no need to wait for the rain while with an input evenly brought a pluviometry of 10 to 15 mm is necessary so that the nitrogen can be transferred to the roots of the cultivation. When you bring the nitrogen evenly during the sowing, if the conditions remain dry your corn can suffer from a lack at a critical stage. Thanks to the in-depth location, the plant has always access to the fertilizer.
Bring the fertilizer as closely as possible to the needs of the plant
- Bringing nitrogen to the plant when she needs it
The corn does not need nitrogen before the 5 leaves stage but absorb 85 % of his nitrogen between the 7 leaves stage and the end of the female blooming. The relatively late needs of the plant do not coincide with the nitrogen inputs sprayed evenly during the sowing. However, a limitation of the nitrogen absorption can cause a loss of yield (number of grains and length of the cob).
- Split application for more efficiency
Spliting the application of fertilization in several intakes will favor the nitrogen optimization. The studies in sandy soil show a systematic advantage with spliting and localizing compared with a single contribution in the sowing. A 3 steps process can be judicious on topsoil.
Avoid burning the plant
Beyond the 3 leaves stage the risk of burns of the cornet are increasing because of spraying solid fertilizer granules.
Fertilize plants, not the adventitious
Localizing allows to fertilize the corn only, not the adventitious! Most of the time the corn weeding is finished when we localize the nitrogen. The localizer Fertill with disks move little the soil and does not cause the production of adventitious.
- Water pollution
During the sowing a massive contribution of nitrogen can be washed in filtering soils. In the sloping grounds, the fertilizer can be carried away by torrential runoff and erosion during thunderstorms. In certain regions for water protection purpose the regulations already impose a spliting of the contributions or a maximal quantity of nitrogen by contribution.
- Air pollution
The volatilization of nitrate fertilizers participates to the air pollution. The protoxide of nitrogen ( N2O) forms at the time of the dénitrification. It is a greenhouse with global warming capability 310 times upper to the CO2. The spliting of the contributions and the application as closely as possible to the needs for the cultivtion are the best way of reducing these emissions.
For you, the volatilization or the washing are a direct economic loss, it is simply some nitrogen which escapes your cultivation.
The localization of nitrogen allows to avoid risks of volatilization and to be more flexible with weather conditions. You are sure that the fertilizer brought will be available for your cultivation and optimized. Thanks to a better placement you can improve your yields or decrease your contributions. We consider that if all the contribution of nitrogen is localized, the total inputs can be reduced by 10 %.