Practice shows that in recent years, Ukraine's agrarians are increasing the area under crops of sunflower, maize, and rapeseed. The problem is that such crops weaken the soil, as it draws a lot of nutrients and moisture out of it. Thus, the fertility of chernozems approaches the minimum values.
The advantage is that after harvesting such a crop, there remain organic remains that support the fertility of the earth.
Note that 10-15% is the volume of organic matter in plant residues. Yes, it's not much, but even such values feed other plants with the necessary substances. It's all about decomposition. After the decay of the residues, microelements are formed, which, in their nutritional properties, sometimes exceed even manure.
Soil fertility directly depends on its composition, and especially on the nitrogen and carbon content. If, on the other hand, the data are based on F.I. Levin (1972) returns to the soil:
- From 27 to 60.5% of nitrogen.
- The value of phosphorus is in the range of 18.5-51.7%.
- Potassium - from 16.7 to 48.1%.
- Calcium returns to a maximum of 54%.
In recent years, vegetative remains of plants, as well as their roots, feed the soil. It also happens that with plant residues more nutrients come in than with high-quality fertilizers. Especially it concerns those plants in which the root system (sunflower, winter wheat) is well pronounced. Thus, their remains are much more valuable than the remnants, for example, of plants with a pronounced stem system.
If, in the process of agriculture, organic fertilizers and plant remains are not introduced, the soil will begin to deplete at the chemical level. This will lead to a decline in nitrogen and, as a result, a complete loss of yield. From this we can conclude that due to stubble root residues, half to 85% of the spent phosphorus, nitrogen and potassium are returned to chernozem. The decomposition of straw is especially nutritious, therefore it is necessary to pay special attention to it. It can not be burnt. The fact is that the temperature on the surface can reach 360 degrees Celsius. At a depth of 5 cm it is lower, but this is enough to burn out humus. As a result, the soil is depleted, the number of microorganisms in this area decreases, but the processability increases.
If, on the other hand, the straw is not burned but left on the field, while compensating for the amount of nitrogen consumed, a significant jump in biological as well as enzymatic activity can be observed. Chernozem receives the necessary amino acids, vitamins and other substances that will only have a positive effect on aeration, nutrient mode and the release of mucus to improve the soil structure.
What crops with a crop endure more phosphorus. Consider this in more detail:
- Corn makes about 37 kg / ha.
- If we talk about rape, the amount is 34 kg / ha.
- For sunflower, this value is slightly less - 29.4 kg / ha.
- Winter wheat is 28.5 kg / ha.
Now, let's consider what crops consume more phosphorus from chernozem:
- The first place is occupied by corn with a value of 25.78 kg / ha.
- Next, rape is 24.57 kg / ha.
- Winter wheat produces an order of 21.16 kg / ha.
From the above results, it can be said that it is maize and canola that are the leaders in the harvesting of nutrients with a grain crop.
It is quite difficult to talk about the level of moisture consumption from the earth, as it depends on the variety of crops grown, the weather itself and some other conditions. Whatever the case, the leaders remain corn, sunflower, and rapeseed. To restore the balance of moisture in the earth, for example, in the steppe, it will take about three years. At the same time, sunflower produces almost the least amount of moisture in comparison with corn or rapeseed. From this it can be concluded that this plant does not affect the fertility of the soil.