Pathways of humate mobilization in soil and its effect on yields

It can now be considered a firmly established fact that soluble forms of humate acids have physiologically active properties, due to which their introduction into the soil increases the yield of a number of agricultural crops. However, there is every reason to believe that an agronomic effect can also be achieved by converting humic fulvic acids of the soil itself into a physiologically active state.

Since only when dissolved do humic and fulvic acids become capable of exhibiting their biologically active properties, which, in our opinion, is associated with their assimilation by the plant, we consider it possible to call this process mobilization.

It is well known that humic acids form soluble compounds with monovalent metals, and insoluble compounds with divalent and higher metals. Obviously, humates can be in forms of different solubility on different soils and, above all, depending on the composition of absorbed cations. In the case of calcium predominance in the composition of the absorbing complex, the solubility of humic acids will decrease, and in the presence of sodium, potassium and ammonium, it will increase. This should undoubtedly affect the vital activity of plants and microflora.

Experimental part

A shortened vegetation experiment was laid out in vessels with a capacity of 1 kg of soil (ordinary chernozem) in 3-fold repetition in two series according to the scheme: control, NaCl, NaHCO ₃ , sodium humate, NH ₄ OH and the same against the background of ammonium nitrate. The rate of these fertilizers, which we consider as a means of mobilizing soil humus, was set at the rate of 0.01 gram equivalent per 1 kg of soil. Ammonium nitrate was given at 0.14 g of nitrogen per vessel, which corresponds to the amount of nitrogen introduced with ammonia water.

Table 1. Dynamics of mobile humic substances in steaming vessels (in % of absolutely dry soil)

Table 2. Dynamics of nitrates and ammonia in steaming vessels

Table 3. Effect of some humus-dispersing agents on the dry matter weight of corn and the accumulation of ammonia, nitrates and mobile humic acids in the soil

Table 4. Effect of fertilizing on the yield of stubble corn under irrigation (Based on field experiments)

Table 5. Effect of fertilizers on the content of protein and sugars in green mass of corn (in % of dry matter)

CONCLUSIONS

1. The introduction of humus-dispersing substances into the soil, such as sodium salts and ammonia water, increases the mobility of humic acids in the soil and converts them into a physiologically active state.
2. The effect of these substances on the crop depends on the properties of the soil and meteorological conditions.
3. The use of these substances on black soils in the presence of mineral food in the soil and under conditions when photosynthesis proceeds normally increases the yield of corn.