Phosphorus sources associated with organic compound in broccoli production and soil chemical attributes

ABSTRACT Phosphorus is a finite natural resource and the use of gradual-release phosphate sources, associated with an organic compound may favor a more rational use of this nutrient, since organic matter protects P from soil fixation. The aim of this study was to evaluate the effect of phosphorus sources application, associated with organic compound at planting, on single inflorescence type broccoli production and soil chemical properties at the end of the cycle. Eight treatments were evaluated, in a 4 x 2 factorial scheme, using four phosphorus sources [thermophosphate (TM), natural phosphate (NP), reactive natural phosphate (RNP) and triple superphosphate (TSP)]; in the presence (55 t ha-1) and absence of organic compound Visafértil® at planting. The experimental design was randomized blocks, with four replicates. TSP source presented higher P contents. TM source showed, in the absence of organic compound, higher pH and contents of organic matter, Ca, Mg, SB and V%. In the presence of organic compound, NP source provided higher contents of organic matter and K. The addition of organic compound increased pH and resulted in higher contents of P, K, Ca, SB, CEC and V%. The presence of organic compound favored higher productivity for the sources TM, NP and TSP. Among these sources, TSP provided the highest production both in the presence or absence of organic compound, considering that NP source was the only one which did not differ from TSP for inflorescence fresh weight and productivity, both in the presence and in the absence of organic compound. We concluded that TSP and NP are the best P sources, associated with the application of organic compound.

摘要 磷是有限的自然资源，与有机化合物结合使用的缓释磷源或许能更合理地利用该养分，因为有机质可保护磷免受土壤固定。本研究旨在评估种植时施用结合有机化合物的磷源，对单花序型西兰花产量及生长周期结束后土壤化学性质的影响。试验采用4×2因子设计，共设8个处理，包含4种磷源：热法磷肥（thermophosphate, TM）、天然磷肥（natural phosphate, NP）、活性天然磷肥（reactive natural phosphate, RNP）以及重过磷酸钙（triple superphosphate, TSP）；并设置种植时添加（55 t·ha⁻¹）与不添加Visafértil®有机物料两个水平。试验设计为随机区组设计，设4次重复。重过磷酸钙（TSP）的磷含量最高。在不添加有机物料的条件下，热法磷肥（TM）处理的土壤pH值、有机质、钙、镁、盐基总量（SB）及盐基饱和度（V%）均更高。而在添加有机物料的条件下，天然磷肥（NP）处理的土壤有机质与钾含量更高。添加有机物料可提升土壤pH值，同时显著提高土壤磷、钾、钙、盐基总量、阳离子交换量（CEC）及盐基饱和度。添加有机物料可使热法磷肥、天然磷肥及重过磷酸钙处理获得更高的产量。无论是否添加有机物料，重过磷酸钙处理的产量均为最高；仅天然磷肥（NP）处理在两种种植条件下的花序鲜重与产量均与重过磷酸钙（TSP）无显著差异。本研究最终得出结论：结合有机物料施用时，重过磷酸钙与天然磷肥为最优磷源。