Manejo de solo sob pastagem antecedendo o cultivo da soja em sistema semeadura direta e integração lavoura-pecuária

Abstract

The low fertility soil and the lack of rain hinder the cultivation of both crops and pastures. The objective was to check the effect of minimum tillage with scarifier, combined with the management of fertilizers and applied to the crop of Urochloa brizantha, prior to soybean cultivation. The experiment was conducted during the agricultural year 2013/2014, 2014/2015 and 2015/2016 in the Experimental Farm of the University of West Paulista, in Presidente Bernardes-SP, in a Ultisol distroferric. The area was divided into two plots of 160m x 167,1m. The experimental design was a factorial scheme 2x5 tracks, with four replications. They were delimited ten treatments of 32 m wide and 167.1 m long in each block, received ten managements: T1: No fertilization and liming without (control); T2: With application of lime; T3: With the application of lime + gypsum; T4: With the application of lime + gypsum + NPK; T5: With the application of lime + gypsum + NPK + micronutrients; T6: No fertilization and liming without (control) + scarification; T7: With application of lime + scarification; T8: With the application of lime + gypsum + scarification; T9: With the application of lime + gypsum + NPK + scarification; T10: With the application of lime + gypsum + NPK + micro + scarification. The parameters evaluated were: chemical analysis of soil, plant tissue analysis, determining the contribution of pasture, initial and final population of plants, number of pods per plant, number of seeds per pod, weight of 100 grains (g), grain yield. Data were submitted to analysis of variance, the Tukey test comparison of means at 5% error probability. Soil use and management led to different chemical changes in management with C + G + NPK + MI in relation to soil fertility during the three agricultural years. Physical managements did not have significant changes in soil fertility. The chemical management of the soil with C + G + NPK had positive effects in relation to the nutrient contents in the trifolium of the soybean crop when the area was not scarified. Physical managements did not benefit the nutrition of soybean plants. In the agricultural year 2013/2014 (Year I) the area that was not scarified, presented the best performance when handled with limestone. In the agricultural year 2014/2015 (Year II) the yield of soybean cultivation was higher when the soil was treated with C + G + NPK + MI, and when the physical management was performed there was no difference. However, yield was 96.2% higher in relation to the first agricultural year. In the agricultural year 2015/2016 (Year III), there was no significant difference in soybean yield, however, there was an increase of 167.1% in the yield of the first agricultural year and 36.1% in relation to the second agricultural year. In the agricultural year 2013/2014 (Year I), the management performed did not have an effect on the dry matter mass of soybean and pasture Uruchloa brizantha cv. Marandu. The mass of the dry matter of the pasture Uruchloa brizantha cv. Piatã in the agricultural year 2014/2015 (Year II) was higher when the area was managed with limestone gypsum and NPK. The mass production of the dry matter of Uruchloa brizantha cv. Piatã in the agricultural year 2015/2016 (Year III), was higher when the soil was handled with limestone and gypsum.