In article recommendations about early-spring top dressing of winter crops are made, criteria of efficiency of introduction of nitric fertilizers are noted. The best fertilizers applied during this period are listed.
Early-spring or winter top dressing of crops of winter crops provoditsya only nitric fertilizers. It is known that superficial podkormka, without the subsequent seal to the soil, phosphoric, potash and kompleksyony fertilizers it is inadmissible, as at superficial introduction the fosyofor and potassium are fixed in a place of contact with the soil and don’t get to a korneobitayemy layer of earth. They aren’t capable to move down on profilyu together with water of a dropping-out precipitation or irrigating. The Effektivyonost podkormok nitric fertilizers is defined by the following usloyoviya.
1. Vlagoobespechennost. Summer and autumn months 2006 were hot and droughty, therefore moisture stocks in the soil under winter kulturami, especially on not steam predecessors, at the beginning of 2007 okazalis small. At limited vlagozapasax doses of nitric udobreyoniya should be low.
2. Condition of crops. Crops should be rather full on the density, protected from weeds, wreckers and diseases. To begin podkormku follows from crops less developed, especially not receiving nitric fertilizer since autumn and showing already now signs of a lack of nitrogen – a pozhelteniye and dying off of the bottom leaves, the slowed-down growth and development. Hoyorosho needs to be fed up the developed crops later not to provoke an unproductive kushcheniye and the accelerated development (especially in the conditions of an oroyosheniye). However all well developed crops should be fed up according to diagnostics of the content of nitrogen in the soil as they are more productive.
3. The content of phosphorus in the soil. First of all follows podkarmlivat nitric fertilizers the crops located in fields with rather high maintenance of mobile forms of phosphorus – more than 2 mg R2O5 in 100 g of the soil, Machigin determined by a method. Such areas in the Crimea more than a half.
In this case we provide high efficiency nitric podkormki, we use for increase in a crop phosphorus brought earlier udobyoreny and in addition we gain effect of interaction in the form of a crop increase.
If on an agrochemical cartogram it is specified that the contents fosfora in this field makes 1 mg R2O5 on 100 g of the soil and less than 1 mg, podkormka winter nitric fertilizers on this field is inexpedient.
Therefore it is necessary to have rather fresh, not out-of-date and qualitative agrochemical cartograms which receive on the basis of the agroyokhimichesky inspection of the fields which has been carried out in strict accordance with the accepted technique, and with obligatory participation of the agronomical personnel of an economy.
At present, in connection with any reorganization and a lack of means, the kartirovaniye is carried out at the wrong time, cards became outdated or they uteryany, and some farmers and don’t understand need to have nadezhyony agrochemical cartograms.
As a last resort it is possible to calculate on not so old cartograms the maintenance of available forms of phosphorus in the soil today and prinyat the decision on expediency of introduction of nitric fertilizers in a concrete field. If cards are lost – it is possible to take them to a copy from PTTs Krymgosplodorodiye archive.
If in an economy there are no agrochemical cartograms – fertilizers vnosyat "blindly" and commit mass mistakes which put sushchestvenyony economic losses. For example, at crops of winter crops phosphates bring on all fields, including on, where security with phosphorus vyyosoky (more than 3 mg R2O5 on 100 g of the soil) and phosphoric fertilizers there not nuzhny. Or carry out nitric top dressing on all areas including on polyax with very low content of phosphorus and, therefore, from nitric fertilizers don’t get a crop rise.
4. The content of potassium in soils of the Crimea for 96 % of the areas sootvetstvuet high security of plants therefore it doesn’t limit primeneyony some nitric fertilizers. On such soils introduction potash tukov or a kayoliya as a part of complex fertilizers in top dressing is absolutely inadmissible. They aren’t necessary and for introduction under the main processing of the soil.
5. The content of nitrogen in the soil. Because of a lack of moisture during the aestivo-autumnal period, after harvesting of not steam predecessors, processes of a mobiyolizatsiya of forms of nitrogen available to plants, in particular, accumulation nitratov, were oppressed. After sternevy predecessors, especially with a straw ostavyoleniye in the field, the nitrogen which is available in the soil, absorbed mikroorganizmy, decomposing straw. It is the inevitable process demanding to 10-15 kg of nitrogen on 1 ton of straw.
Precisely to establish necessary norm of nitric fertilizer for early-spring top dressing, it is necessary to carry out diagnostics of security of plants by nitrogen – visual, fabric, sheet or soil. Pochyovenny diagnostics is used more often, as the most reliable. Schitaetsya that the meter layer of earth by the beginning of active vegetation of plants should contain 100-120 kg/hectares of nitratny nitrogen (N-NO3). The specified koyolichestvo of easily available nitrogen (and even much more) can be under wheat on black steam if steam was such what it should be according to agrotechnical requirements. But it is necessary to be convinced of it at least on otyodelny typical fields.
For winter crops after other predecessors norm of nitrogen prixoditsya to establish a method of a dovneseniye of the N-NO3 koliyochestvo lacking to 120 kg/hectare. It provides receiving the crop close to greatest possible at developing weather conditions, but doesn’t guarantee formation of high-quality grain of winter wheat.
For formation of a big crop of qualitative grain in a meter layer of earth should contain, depending on planned urozhajnosti, to 180-200 kg/hectares of N-NO3. Such amount of easily available nitrogen in the soil can collect only in black to pair, after other predecessors it is necessary dovnosit so much nitrogen, how many follows by results diagnostiki.
The single dose of nitrogen shouldn’t be less than 30 kg/hectares. At a lack of fertilizers it is better to fertilize a smaller dose the big area if on all area such top dressing is justifiable (proceeding from conditions of its effekyotivnost, for example, at the sufficient content of phosphorus in the soil, etc.).
Carrying out soil diagnostics – work rather difficult texnicheski, demands good analytical preparation. As a last resort it is possible to use settlement methods, for example, a method of chair of agrochemistry of YuF "KATU" NAU. Considering vlagoobespechennost conditions, and also an economic condition of farms, for steppe areas it is possible rekomendovat norm of nitrogen to 50-60 kg/hectares of nitrogen, for foothill – to 70-80 kg/hectares. In irrigated conditions norm increase to 100-120 kg/hectares.
6. The best fertilizers for early-spring top dressing of winter crops by nitrogen are ammoniyny (ammoniac) saltpeter and a carbamide (mochevina). At the correct application of equal doses of nitrogen during the cold period of year these fertilizers influence productivity and quality of grain of fertilized cultures approximately is identical. It is necessary to choose that of fertilizers in which the sum of expenses for acquisition, delivery and introduction of 1 kg of nitrogen will be miniyomalny.
The carbamide doesn’t dissociate on ions and doesn’t communicate the soil. The Sposobyonost to migration with water on a soil profile at it is slightly less, than at the nitrates which are a part of ammoniyny saltpeter. In the cold soil (<10°S) the carbamide isn’t exposed to an ammonifikatsiya. It is capable to move deep into to roots of plants as well as ammoniac saltpeter – for the account an osypayoniya to emptiness of a friable blanket of the soil, with falling on profilyu moisture of dropping-out rains and thawing snow.
In the spring, at temperature increase from above 8-10°S, the carbamide at contact to urobakteriya in the soil is exposed to an ammonifikatsiya and for this reason considerable losses of nitrogen in the form of ammonia are possible. However the fertilizer zayodelka to the soil, even on 1,5 cm, sharply reduces losses – at temperature soils 6°S they make 0,2 %, and at 20°S – 3 %.
7. Uniformity of distribution of fertilizers on the area has ogyoromny value. High uniformity is provided at application of fertilizers by modern tukorazbrasyvatel such as Amazon, Sulka, etc., and also grain disk seeders. Type 1-RMG-4, NRU-05 spreaders, etc. need careful adjustment, the podyogotovka of fertilizers to introduction, optimization of distances between passes of units is necessary also.
During the cold period of year seal of fertilizers to the soil isn’t required. In March, at achievement by the soil of physical ripeness, maximum efficiency of a carbamide and ammoniac saltpeter is provided with their local entering into the soil disk grain seeders.
In one of experiences, at high precision of distribution of 100 kg/hectares azota, productivity of winter wheat at introduction of ammoniyny saltpeter (Naa) and a carbamide (Nm) was identical – 41,5 c/hectares. At an insufficient ravnomeryonost of scattering of fertilizers productivity in option with Naa decreased on 10,1 c/hectare (24,3 %), and in option with Nm – on 15,2 c/hectares (36,6 %)
Unevenness of application of fertilizers leads to big losses, especially at the raised doses therefore is inadmissible to "save" on their vneyoseniye as to 90-95 % of expenses it is the share of their acquisition, delivery and storage. A carbamide – more concentrated fertilizer therefore and poteri from unevenness of its introduction can be more.
8. It is necessary to remember that the lack of a mineral food of rasteyoniya can’t be compensated by stimulators and regulators of growth of rasyoteniye, application modern Kristallonov, Akvarinov, fertilizers on the basis of sapropels and other preparations applied in number of 2-3 kg/hectares. They can be effective against high security of plants with basic elements of a mineral food.
A.Gapiyenko, department chair of the general and agronomical chemistry of YuF "KATU" NAU, professor.