Atributos agronômicos do sorgo forrageiro em latossolos da Amazônia em função da adubação fosfatada, nitrogenada e calagem.

Abstract

The cattle one in the Amazon tries an extraordinary growth in its productivity, however still there are limiting factors exist as low the production of fodder plant for occasion of the period of scarcity of rains. The ensilage appears as good alternative to brighten up this problem and Sorghum bicolor is considered one of the indicated cultures for this practical, having been that the adequate handling is basic for the attainment of a material of good quality. Ahead of this practical of the liming and the fertilization with phosphorous and nitrogen they assume important role for a good development and production of the sorghum.This work had for objective to evaluate the growth and production of sorghum in function of the fertilization with phosphorous and nitrogen and liming in Latossolos Amarelos. Two experiments, one in conditions of field and another one in vegetation house had been lead, both in the dependences of the Instituto de ciências agrárias (ICA) da Universidade Federal Rural da Amazônia (UFRA). In experiment of field the objective was evaluated the green leaf mass production and the height of plants of the sorghum in function of different leveis of fertilization with nitrogen and phosphorous in a randomized block experimental design, four phosphorous leveis fertilization: 50, 100, 150 and 200 kg ha"1 of P2O5 and three nitrogen levei fertilization; 60, 100 e 140 kg ha'1 de N. In the experiment The objective was to evaluate the effect of different phosphorous sources and saturations of bases in leaf evaluate the growth and production of the Sorghum. The experimental design was a completely randomized in factorial scheme 4x4, with 4 replications. Four phosphorous sources: 1) Control (P0), 2) Phosfate Reative(ARAD), 3) triple superphosphate (TSF) and 4) mixed of ARAD and triple superphosphate (ARAD+TSF) at 50:50 relation and four differents leveis of soil base saturation distribuited as 1) 39% of natural soil base saturation, 2) 60% of soil base saturation, 3) 80% of soil base saturation, and 4) 100% of soil base saturation. The results of the experiment of the field had shown that the interaction of the doses of P with the doses of N had significantly influenced the growth and the production of sorghum. In the leveis of 100 and 140 kg ha"1 of N combined with the levei of 150 kg ha"f of P2O5 had been gotten the biggest productions of dry mass and green mass of the aerial part, respectively. The maximum production esteem of green mass and dry mass of 17.572 the aerial part was of 53.760 kg ha"1, being that the corresponding production 90% of the 15.436 principie was of 48.384 kg ha"1, to leveis maxims of 122 and 136 kg ha"1 P2O5 and criticai leveis of 65 and 81 kg ha"1 P2O5, associate to the leveis of 100 and 140 kg ha'1 of N, respectively. The results of the experiment in green house had shown that the sources of P and the liming had positively influenced the growth and the production of sorghum. Source ARAD+SFT combined with the saturation for 60% bases was the one that promoted greaters productions of dry mass and green mass of the aerial part. Under source SFT and the natural saturation for bases of the ground the biggest relation was found root and aerial part.

Nitrogen and phosphorous are essential elements for the development of sorghum and have great amounts extracted and exported by the plants demonstrating that the replacement of these two elements to the ground cannot be limiting in the systems of ensilage production.The objective of this study was evaluated the growth and production of the sorghum in function of different leveis of fertilization with nitrogen and phosphorous in a randomized biock experimentai desígn, four phosphorous leveis fertilization: 50, 100, 150 and 200 kg ha4 of P2O5 and three nitrogen levei fertilization: 60, 100 e 140 kg ha4 de N. The source of phosphorous used was single superphosphate, and the source of nitrogen was ammonium sulfate and urea. The interaction of the leveis of P with the doses of N had significantly influenced the growth and the production of sorghum. In the leveis of 100 and 140 kg ha4 of N combined with the levei of 150 kg ha4 of P2O5 had been gotten the biggest productions of dry mass and green mass of the aerial part. The esteem maximum production of green mass was of 53.760 kg ha4 and dry mass of was of 17.572 kg ha4 of the aerial part, being that the corresponding production 90% of the principie was of 48.384, to leveis maxims of 122 and 136 kg ha4 P2O5 and criticai leveis of 65 and 81 kg ha4 P2O5, associate to the leveis of 100 and 140 kg ha4 of N, respectively.

The liming and the fertilization with phosphorous are practical necessary in ground with raised acidity, that normally present low match concentration. As the majority of Amazon ground it presents such characteristics, a good productivity of the plants, as it is the case of sorghum, is dependent of the use of such practical. The choice of the source of P adjusted for better suppliment of this nutrient to the plants and attainment of a satisfactory production, as well as a good relation cost-production, also becomes necessary. The objective was to evaluate the effect of different phosphorous sources and saturations of bases in leaf evaluate the growth and production of the Sorghum. The experimental design was a completely randomized in factorial scheme 4x4, with 4 replications. Four phosphorous sources: 1) Control (P0), 2) Phosfate Reative(ARAD), 3) triple superphosphate (TSF) and 4) mixed of ARAD and triple superphosphate (ARAD+TSF) at 50:50 relation and four differents leveis of soil base saturation distribuited as 1) 39% of natural soil base saturation, 2) 60% of soil base saturation, 3) 80% of soil base saturation, and 4) 100% of soil base saturation.The sources of P and the liming had positively influenced the growth and the production of sorghum. The source ARAD+SFT combined with the saturation for 60% bases was the one that promoted greaters productions of dry mass and green mass of the aerial part. Under source SFT and the natural saturation for bases of the ground the biggest relation was found root and aerial part.