Liquid manure
Liquid manure — organic fertilizer, is fermented animal urine flowing into slurry collectors of livestock buildings and manure storage facilities. On average, it accounts for 10-15% of the mass of fresh manure, but varies depending on the storage method. With a sufficient amount of peat bedding, liquid manure usually does not accumulate.
From 10 t of fresh bedded manure, over 4 months, 170 L of liquid manure is released under dense storage, 450 L under loose-dense storage, and 1000 L under loose storage; that is, the faster the manure decomposes, the more liquid manure is released (VNIIUA).
Composition
Nutrient content varies. On average, it contains 0.25-0.30% N, 0.4-0.5% K2O, and 0.01-0.06% P2O5. In effectiveness, it is not inferior to equivalent doses of mineral fertilizers. The content of nutrients changes depending on the rations and species of animals and the methods of accumulation and storage of liquid manure: from 0.01% to 1.0% nitrogen, from 0.05% to 1.2% K2O.
Table. Nutrient content in liquid manure.
| Samples of liquid manure from slurry collectors | Number of samples | Average content, % | ||
|---|---|---|---|---|
| nitrogen (N) | potassium (K2O) | phosphorus (P2O5) | ||
| At dairy farms | 63 | 0.26 | 0.38 | 0.12 |
| At pig farms | 12 | 0.31 | 0.36 | 0.06 |
| At horse stables | 18 | 0.39 | 0.58 | 0.08 |
The main nitrogenous substances in liquid manure are urea, uric acid, and hippuric acid, which under the action of ureobacteria are converted into ammonium carbonate, which decomposes into carbon dioxide, ammonia, and water. Uric acid is converted into urea, and the latter into ammonium carbonate:
Collection and storage
Ammonia, which forms during the decomposition of ammonium carbonate, leads to nitrogen losses from liquid manure. To reduce nitrogen losses, a sufficient amount of bedding is used, 3-5% superphosphate by mass of the liquid manure is added, and sewage systems in cattle yards are arranged so that urine does not remain in the gutters. Slurry settling tanks are periodically cleaned of sediment so that settled liquid manure enters the slurry collector. To avoid ammonia losses, slurry collectors must be tightly closed.
In cattle yards without slurry collectors, slurry drains are filled with peat, replacing it each time after saturation with liquid manure. During the stall period (220-240 days), about 2 t of liquid manure is collected from each cow or 10-12 calves.
Use
Liquid manure can be used year-round: for preparing composts, fertilizing winter crops, fertilizing row crops, and applying under fall plowing. Composts can be prepared from the onset of warm March days until autumn.
Liquid manure can be applied in pure form before sowing and for fertilizing with rapid incorporation into the soil, and as part of composts — before sowing of crops. Pre-sowing application rates range from 20 to 50 t/ha depending on the quality of the liquid manure, the requirements of the fertilized crops, and the degree of soil cultivation. For fertilizing perennial grasses in crop rotations, on meadows and pastures, 10-30 t/ha is applied; in the interrows of row crops — 8-15 t/ha.
For fertilizing winter crops, meadows, and pastures, 3-5 t of liquid manure diluted 2-3 times with water is used. This technique allows the liquid manure to be distributed evenly over the area, reduces nitrogen losses, and prevents plant burns. If the liquid manure is diluted with water during accumulation and its nitrogen content is not more than 0.2-0.25%, it is not recommended to dilute it before surface fertilizing. Winter crops are harrowed after fertilizing. Delay in harrowing leads to ammonia losses and reduced effectiveness. When fertilizing vegetable and row crops, liquid manure is applied using tankers with the PRZh-1.7 fertilizing attachment, which ensures application at the specified depth and without nitrogen losses. Dilution with water is not required with this application method.
At the first fertilizing of row crops, liquid manure is applied to the side of the row at 5-7 t/ha; at the second — into the middle of the interrow at 8-12 t/ha.
As a main fertilizer, it is applied at 10-20 t/ha depending on the needs and characteristics of the crop. To avoid nitrogen losses, liquid manure spread over arable land is immediately plowed in.
One ton of liquid manure, when applied correctly, increases crop yield by 1 centner/ha of grain units, and when superphosphate is added, increases its effectiveness (due to the low phosphorus content in the liquid manure). The maximum effect is achieved by composting with peat or other organic components.
References
1. Yagodin B. A., Zhukov Yu. P., Kobzarenko V. I. (2002). Agrochemistry. Ed. B. A. Yagodin. Moscow: Kolos.
2. Mineev V. G., Sychev V. G., Gamzikov G. P. et al. (2017). Agrochemistry. Textbook. Ed. V. G. Mineev. Moscow: Publishing House of the D. N. Pryanishnikov VNIIA.
