NON-TRADITIONAL AMELIORANTS - Fertilizers: Components, Uses in Agriculture and Environmental Impacts - page 202

We have developed a new way of entering it - mixing bentonite clay with upper five-
centimeters layer of the soil, namely the creation of mulch on the surface layer (Patent № 21-
64060 RUС2). This method allowed to drastically reduce the dose of entering ameliorant
without reducing its effectiveness. We studied three doses of application of 4, 8, and 16 t-ha -1 .
In most cases, the application dose 8 t-ha -1 was provided the most effective. Dose of 4 t-
ha -1 shown mathematically significant effect only with simultaneous application of bentonite
clay and limestone flour in a dose of 4 t-ha -1 . Consider the effect of a mulch layer of bentonite
clay on the basic properties of sod-podzolic soils.
E FFECT OF B ENTONITE C LAY ON P HYSICOCHEMICAL P ROPERTIES
The main effect of bentonite clay on physicochemical properties manifested in a
significant increase in the absorptive capacity of the soils, especially in relation to the cation
(Figure 1). This is due to the high content of montmorillonite in bentonite clay.
Montmorillonite has, as already mentioned, very high cation exchange capacity (CEC) -
90-120 mmol-100 grams -1 of the mineral. In our experiments we studied bentonite clay from
Biklyan deposit (Tatarstan, Russia), it had the CEC - 96 mmol-100 g -1 . Moreover, during the
receipt of the this ameliorant, feedstock ground in the roller-pendular mill and sieved through
a sieve set, the hole diameter of the last - 0,074 mm. Prepared in this way bentonite clay
contains 50-60% fraction of silty particles.
For sod-podzolic soils with a small total exchangeable bases (on average 10-15 mmol-
100 g -1 soil), increase CEC is a very important positive effect of the ameliorant. The increase
in the absorptive capacity allow to reduce washing away of mineral nutrients from the topsoil,
more efficient use of mineral fertilizers, increase the buffer capacity of soils.
Figure 1. Effect of bentonite clay ploughed in the 0-5 cm soil layer on the total exchangeable bases of
the arable layer, % deviations from control (no ameliorant).