CULTAN Fertilization

CULTAN (Controlled Uptake Long Term Ammonium Nutrition, German: controlled long-term ammonium nutrition) is a rather rare form of fertilization supplying nitrogen to crops. It was developed by Bonner agricultural scientist Karl Sommer from the late 1960s and is among others the case of grassland in arable farming in cereals, maize, potatoes and beets, as well as in the wine and used in nurseries. It costs more than calcium ammonium nitrate (including expected output ).

Nitrogen fertilization of the plants is carried out in this process - unlike conventional fertilizers method - only once for one growing season with ammonium (NH4 ) instead of nitrate (NO3 -N). The fertilizer is not applied to the soil or incorporated into a wide area, but at points or in strip form is introduced into the soil.

With a special injection technique is attempted, the fertilizer solution deep seven to 20 cm offset slightly to the side in the bottom to place the seed or plant rows. In row crops with larger number of intervals such as potatoes, beets or corn as it is technically solvable with some effort. Usually, however, the Cultanverfahren used in cereals and oilseed rape, have the number intervals of about 10 cm. There is no laterally offset output is possible, on the contrary, it is an - albeit small - share plants hit and destroyed by the injection technique.

• 6.1 Criticism of ASL and Blue sulfates

Mechanism of action

When nitrogen fertilization only a part of the fertilizer is absorbed by the plant. From water washed out or discharged to the air nitrogen is lost and leads to significant environmental problems (eutrophication, nitrous oxide ). Karl Sommer sees advantages in when applied near the roots of highly concentrated ammonium fertilizer. The effect of ammonium based depots significantly on the phytotoxicity of ammonium. Evenly distributed in the rhizosphere ammonium could also be included both active and passive of the plants. With active recording it would be taken at the root directly in the metabolism of organic N compounds. In the passive recording, it could, however, be accumulated in mature leaves, where even low concentrations of growth disorders provoked. At higher concentrations, necrosis would be formed at the leaf margins by ammonium. In addition, ammonium diminish in the root zone distributes the uptake of other cations.

These negative effects of ammonium would not occur during CULTAN process, as it is not distributed equally present in the soil, but in limited, highly concentrated portfolios. The deposits occupy only a small part of the root-permeable from a plant soil volume. The remaining root zone remain relatively free of ammonium ions, so that there can take place a stable supply of other nutrients.

In contrast to the uniformly distributed ammonium came at depots few roots at the interfaces with the ammonium in contact. There, these roots would only take up ammonium from the depots when they are supplied with sufficient carbohydrates from the shoot. In this case, the ammonium ion would be recorded directly in the metabolism of organic nitrogen compounds. Thus, the ammonium uptake successes by the plant itself regulated according to their current " assimilatory power ". From this the conclusion could be drawn that the growth potential of the plant will always be fully exhausted, according to the weather conditions and no power supply is possible at the same time.

The plants would grow thereby targeted to the interfaces of the deposit back and around it. With consumption of the nitrogen in the border areas, the root tips would grow and so the entire depot until complete emptying of age. On the basis of a report drawn up by the summer of root image can be a root system recognize around the depot. More such pictures are still missing.

Under the terms of nitrogen uptake from the concentrated ammonium depots is changing in the wake of the whole metabolism. Since the location of the nitrogen incorporation would be transferred from the leaves to the roots, also the concentrations of the substances and the resulting osmotic pressures alters. These changes, which are commonly referred to as biological source -sink effects, leading to improving the growth and quality of plants.

General doctrine vs. CULTAN

A direct uptake of ammonium contradicts the current state of the science. Because of nitrification in soil is assumed according to conventional school of thought that regardless of the fertilized forms of nitrogen, ammoniacal or urea nitrogen for the plants eventually become available as nitrate ( See also: the nitrogen cycle ).

Field trials

To what extent the observed positive effects of summer on the most unnaturally high amount of sulfur ( about 150 kg / ha) are due, he leaves it unclear. In fertilization experiments, a sulfur balance is partly given up to an altitude of 80 kg / ha wettable sulfur, which showed significantly more positive effects than the sulfur transfer by injection fertilization

A three-year investigation of the Department of Agriculture at the District Office Breisgau in the Black Forest expects similar results to summer, to speak of good scientific evidence if the results is only to be expected simply wrong. Also, researchers at the University of Bonn, at which summer were taught not achieve equivalent yield results in vegetables.

CULTAN is characterized on the one hand by an elaborate theoretical foundation, can on the other side of the meager available data in terms of the required capital expenditure and yield considerable doubts about practicality, marketability and acceptance among agricultural producers pay.

Equally amazing is the lack of information flow on the growth of circumstances where Cultan fertilization with higher yields were obtained.

• So simple income amounts are compared with rape, without addressing the important oil yields per hectare. Here, the Cultan method is compared with conventional fertilization practice, however, without mentioning amount of fertilizer, fertilizer, growth stage or application dates, also praxisunübliche rape varieties are used.
• In other experiments, manure is injected by Cultan method and compared with horn meal. This will hide the fact that they are a multi-nutrient fertilizer with manure, in particular beet respond positively to potassium and phosphorus gifts.
• In malting barley also Cultan fertilization was tested. Here spring malting barley was eingesäht on a damaged by geese feeding wheat area. Since the editing was done without a plow, differences can take great influence by uneven feeding geese. It was also used as a comparison to the pure nitrogen Cultan fertilizer mineral fertilizer, which can increase the salt concentration in the unfavorable heights by the potash. Basically, the results of basic seed or certified seed is used at least in field trials for reasons of comparability and resilience. In this case, farm-saved seed was used. A sulfur balance did not take place.

In a 2010 experiment conducted in the Cultan fertilization cut in all disciplines worse: Whether crude protein or income, amount of income, regardless of the nitrogen fertilizer amount could not be ascertained advantages of an ammonium -sulfur injection.

Back in 2004, when the strength of potato Agria A fertilization experiment was conducted by the University of Bonn. The starch contents and goods market yields were the same as for the conventional fertilization with calcium ammonium nitrate fertilizer at the same height. If the nitrogen application reduced, this also had partly directly with yield losses in quantity and starch yield.

In 2008-2009, the Cultan fertilization was examined by the Chamber of Agriculture of Lower Saxony at three locations. Here, too, there was not the promised by some contractors significant yield increases for the same level of nitrogen fertilization. Again, nitrate levels is spoken of luxury consumption for the first grass cut and dangerously high.

Scientific studies the influences that the injection fertilization on plant health and ammonium nutrition, but are still missing ..

Research and Development

For many decades CULTAN method is worked on, the beginning is seen about in the 1970s. The essential foundations were laid by the high school teacher Karl Sommer at the University of Bonn, where to this day, the beginning of the 21st century, continue research on injection fertilization is operated (especially liquid manure injection). The application process is researched in Germany in particular from Braunschweig Julius Kühn - Institut, Federal Research Centre for Cultivated Plants (JKI ), Institute of Crop and Soil Science. Internationally, several research institutions deal with the CULTAN injection fertilization.

Events found sporadically held in different countries, while there are field demonstrations, workshops and symposia. An international symposium on " injection fertilization - Current state of knowledge, new developments and experiences" with over 100 participants was conducted in February 2010 in Braunschweig, the Julius Kühn Institute. In this context it should be noted that inter alia falling and the practical standard prescribed in the Netherlands under slurry injection subject.

Since the beginning of the 21st century, an increasing at a low level use in agricultural practice seems to be happening. 2004 were processed with 10 injection machines in CULTAN procedure in Germany about 10,000 hectares. 2009/2010 there were about 70,000 acres with the help of 44 machines. Other sources speak of 100,000 hectares in Germany. Thus, the CULTAN procedure for 2010 was less than 1% of the German agricultural area used.

Technology

Depending on the plant culture different depot forms (ball, cup depots, etc.) are used, which require different application technique.

The most well-known in Europe, default and ammonium fertilizer form is the direct fertilization in maize.

Tailwheel method

Summer significantly developed the tail wheel technology. It denotes a CULTAN injection technique in which a liquid fertilizer from a tank -supplied tail wheel injector is moved over the area to be fertilized. However, this is only used by individual contractors.

A single tail wheel consists of a metal hoop with usually twelve hollow spokes pipes. On each of these tubes sits a hollow spur ( also sting or Spoke called ), which is supplied by the fertilizer tank via pressure hose, hub and spokes tube with the fertilizer. On the spur head is a lateral hole through which the fertilizer is injected with 1.5 to 8 bar in the ground. After the injection of the respective spur into the ground, the channel between the pressure tube and spokes tube is mechanically opened.

With modern instruments, a controller adjusts the amount of fertilizer at different working speeds. The membrane pump and the control valves of the Injektorgerätes be controlled. The Spurs and wheels from different manufacturers differ slightly, but function basically the same and are based on a design by Karl Sommer.

Cultivator or harrow

In addition to the Spornradtechnik Cultan fertilization is performed with the help of grooming and multitudes, which means less technical effort. The Horsch has the duet coulter found a way to simultaneously deploy seed and fertilizer.

Sprayer

With conventional syringes NH4- based fertilizers can also be applied. You must have on drag hoses, as some NH4- fertilizers are not suitable for foliar application. This drag hoses lay depots also from a strip. However, the spray boom must be kept very low. In addition, weights are on the hose ends duty, so that the hoses do not lose by the plant canopy to the ground. The vehicle speed must be reduced accordingly to prevent chapping of the hoses, and damage to the pendulum rod.

Used fertilizer

Frequently ammonium sulfate solution or Blue sulfates are used. Besides Urea ammonium nitrate solution (UAN ), NH3 -Stark water and monoammonium phosphate come (MAP ) and diammonium phosphate (DAP; commonly because of the content values ​​18 x 46 called ) are used.

Criticism of ASL and Blue sulfates

Especially ASL and the similar blue sulfates are the focus of critics.

• Sulfur fertilizer live off largely independent of the shape that Kalkvorräte on, per 100 kg of nitrogen fertilization by ASL has approximately 200 kg CaO expected withdrawal.
• Among other things, ASL is obtained during the exhaust or emission control. Likewise, in the production of hydrocyanic acid of this material occurs ..
• The sulfur contained in Blue sulfates is about 9 % by weight at the same time about 8% nitrogen content. According to a nitrogen fertilization of rape of 150 kg / ha of nitrogen, 170 kg / ha sulfur are applied. The sulfur requirements of canola is about 60 kg / ha. In continuous use of Blue sulfates risk of Schwefelauswaschung is the groundwater high. Calculations show that - at a groundwater recharge of 100 m annually - a leaching of 80 kg / ha of sulfur is sufficient to exceed the limit in the groundwater.

Disadvantages and conditions

• A stock with the CULTAN fertilization process is seen on grassland critical. Due to the increased N supply there might be alarming nitrate levels in the nursery. This can lead to health problems in animals. In particular, one must take into account on grassland re-supply of nitrogen from organic manure slurry with because grassland is mostly managed by livestock -intensive businesses.

• The agricultural machinery required for the CULTAN use are significantly more expensive than conventional fertilizer spreader, so that the method is mainly offered by specialist contractors. This argument is often called, but is not durable.

• In simple, strip-shaped tray, it may inter alia, heavy precipitation, lead to a decrease in the concentration in the depot and thus undesirable effect of faster CULTAN fertilizer. By use of a spur gear, this can be prevented.

• If the culture in between wraps for other reasons ( herbicide damage, economic surplus by eg potatoes instead of grain ), or it can not be fully utilized, the nitrogen for other reasons such as drought, there is a distribution of ammonium in the soil. As a result, it kommte to leaching. On dry sandy soils may be beneficial targeted Cultandüngung however, because the nutrients are available immediately for the growing season, and not have to wait for uncertain rainfall.

• Problems seem to prepare stony soils. So is reported that there are problems with splashed CULTAN fertilizer, if he does not manage to cut stones. In particular, the part used ammonium sulfate solution (ASL ) has at pH values ​​below 4 with the addition not be marked suitable for foliar application .. In severe and simultaneously dry soils similar problems seem to occur.

• Depending on the technology there seems to be problems with sticky floor or when applied in the morning dew. In addition, it may lead to reduced yields in lanes.

• Depending on the technology and operating conditions can cause a blockage or cancel Spornraddüsen ..

• Critical it is seen that at the time of application is not known how much of the crop plant is actually required. Factors include the weather conditions, which in turn the Stickstoffnachlieferungsvermögen of the soil such as influence of organic fertilizers.

• In addition, at the time the Cultan fertilization unclear what quantities of nitrogen will escape the culture through its different from year to year yield formation.

• Modern sensor technology ( N-Sensor, Crop -meter ) or Nmin samples are no longer usable for fertilizer cost reduction, since the entire nitrogen application has been carried out by the CULTAN process.

• A site specific nitrogen fertilization and thus corrections of soil differences, as well as growth stalls within a shock are very restricted.

• Prerequisite for potato fertilization is the right timing and placing of CULTAN fertilizer .. So it must be ensured that the depot is created below the seed potatoes. In addition, this must be done at a time when the root systems are not damaged by the injection coulters. The Nmin content of the soil should be low for good luck and the amount of organic fertilizer not exceed one third of the demand.

• The results referred to by Cultan sellers are only to be expected if the soil has a low mineral nitrogen content start of the experiment and a low mineralization capacity during culture. Both are predominantly on vegetable cropping soils rarely the case. The reports of very high yields after CULTAN - fertilization of practice is important to note that the nitrogen quantities used are very high in some cases.

• With weeping damaged stocks, most recently in Germany in winter 1998/1999, was formerly accepted knowledge that they are to be angedüngt with nitrate. To what extent CULTAN fertilization provides a way here is unclear.

• It must be ensured that the output occurs very precise. First of all defects and double treatments are avoided as there is in most cases the entire amount of nitrogen needed per year is applied. Otherwise, there are missing or duplicate fertilizers on part surfaces. In contrast to mineral fertilization, the risk of Ausbringfehlern focused on a crossing and fertilizers. Nachdüngungen are hardly possible in later growth phases with the most heavy equipment, also the roots of which are advanced in growth stocks would only grow to the depot. The application can also be done using Schaummarkierern with quality GPS systems or on smaller areas.

• The Ausbringtermin must - Notwithstanding any other statements of the scientist summer - apparently are also present in the injection fertilization in the area of ​​the vegetation onset, so as not to endanger the corn plant by nitrogen deficiency. (comparative statement of the magazine also practical 1/2011 )