In the tropical environment, the low soil's natural fertility and forage yield seasonality
are significant challenges for animal production on pasture, especially in sandy soils.
Thus, the aim of this study was to evaluate the contribution of gypsum (0, 200, 750,
1500, and 2250 kg ha -1 ) combined with liming + NPK fertilization, in addition to the
treatments only NPK and the control (without fertilization or correctives), on forage
production and root development of Marandu grass (Urochloa brizantha). The
experiment was conducted under field conditions, in a randomized block design, with
seven treatments and four replications. 3000 kg ha -1 of dolomitic lime was applied and
for the NPK we used 100 kg ha -1 of N (urea), 50 kg ha -1 of P 2 O 5 (triple superphosphate)
and 100 kg ha -1 of K 2 O (chloride of potassium). Soil fertility improvement strategies
promoted changes in soil chemical attributes at six and twelve months. In the soil
surface layer, the lime and gypsum increased pH and calcium content, in addition to
reducing aluminum saturation, in addition, the fertilization increased phosphorus and
potassium levels too. In the subsurface layers, from 50 to 110 cm, calcium and
magnesium contents increased and aluminum saturation decreased due gypsum
addiction. The Marandu grass root mass increased, in the soil profile, with NPK and
gypsum application. In the first and second years of evaluation, the strategies of
combining or not gypsum + lime and fertilization showed greater height, tiller density,
and forage mass per cycle and total compared to the control. Only in the second year
was observed difference between the strategies, and the application of gypsum
allowed greater increments in height, tiller density and forage mass per cycle and total.
The strategy that involves limestone and gypsum promotes better benefits on surface
and subsurface soil fertility and stands out for minimizing the seasonality of forage
production by stimulating forage growth in the wet-dry and dry-wet transition periods.
Fertilization with NPK and gypsum increases Marandu grass root mass in the soil
profile. The combination of fertilization with NPK plus lime and gypsum presents better
performance on production and pasture recovery.
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