Agriculture Reference
In-Depth Information
Applying a mulch layer of limestone powder slightly reduced the content of humus in the
plow horizon in the first three years and then, in the fourth and fifth years, increased it
slightly. This contradictory effect of liming is explained by the positive impact it has on the
two opposite processes of organic matter transformation: mineralization and humification.
The predominance of one process over the other is determined by a number of external
factors. The five years of observation revealed only a slight increase in the humus content by
the average of 1.5% at a low confidence level compared with the control.
The effect of mulches on the content of mineral nutrients in the soil depended on their
chemical composition. The greatest effect on the amount of labile phosphorus and exchange
potassium in the soil was achieved by the application of peat at 40 t/ha to the top of the plow
horizon, which increased the content of the above elements by the average of 14.7 and 10.7%,
respectively during the five years of observation (Figures 5 and 6).
In both cases this increase was statistically provable at a high level of confidence.
Mulching with peat also increased the content of nitrate nitrogen in the plow horizon (by the
average of 8.3% during the five years), but this increase was not always proved statistically
by years.
The increase in the content of mineral nutrients in the soil was due to the fact that they
were part of the mulch's organic matter and were released in the process of its mineralization.
At the standard humidity of 60%, one ton of low-moor peat contains 20-30 kg of nitrogen, 2-
3 kg of phosphorus and 1-2 kg of potassium (Tishkovich, 1993).
It should be noted that deep incorporation of peat increased the content of nutrients by a
lower value (3-7% on average compared with the control without peat). This proves that
mixing peat with the soil layer of 0-5 cm makes it not only a valuable organic fertilizer, but
an effective mulch material that improves the nutrient status of the soil on the whole.
Figure 5. Effect of mulches on the content of labile phosphorus in the plow horizon.
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