Crop rotation, cover crops introduction and no tillage adoption have improved tropical agriculture sustainability through improvements on soil conservation and water use efficiency. Soil fertility and topsoil phosphorus (P) accumulation is also altered by management, affecting P dynamics and its use for subsequent cash crops. Changes in soil P fractions promoted by no-tillage (NT) and conventional tillage (CT) in soybean/cotton crop systems with different cover crop rotations (fallow, maize as second crop, brachiaria and millet) were investigated in two long-term trials in Brazilian Oxisols (Ox-1 and Ox-2), and compared to soils under native Cerrado vegetation. Hedley’s P fractionation was performed in soil samples taken from 0 to 5, 5 to 10 and 10 to 20 cm depth layers and P fractions grouped by their predicted lability. Long-term cultivation generated large amounts of legacy P in the soil (184−341 mg kg⁻¹) but only a small portion remained in labile fractions (11–16 %), with a slight increase in non-labile P (<5 %) and organic P (10–20 %) concentrations under NT when compared to CT. Although the soil P remained mostly in less available fractions, the legacy P obtained by the difference between the soil P data from the agricultural land and the native area provided a useful approach for P accumulation estimative over the time, very close to the predicted P inputs/outputs accounting. Brachiaria recycled more P than other cover crops, increasing the labile P (5–20 %) and all the organic P fractions (10–25 %) over the time.

轮作，覆盖作物的引入以及不采用耕种的方式通过改善土壤保持和水资源利用效率而提高了热带农业的可持续性。土壤肥力和表层土壤磷（P）的积累也因管理而改变，影响了磷的动态及其在随后经济作物中的使用。在两项长期试验中，研究了不同耕作轮作的大豆/棉农作物系统（免耕，玉米作为第二作物，腕带菜和小米）的免耕（NT）和常规耕作（CT）促进了土壤P组分的变化。在巴西的Oxisol（Ox-1和Ox-2）中进行了比较，并与天然Cerrado植被下的土壤进行了比较。Hedley的P分馏是在从0至5、5至10和10至20 cm深度的土壤样品中进行的，P组分按其预测的不稳定性分组。^-1），但与CT相比，NT下非不稳定P（<5％）和有机P（10-20％）的浓度略有增加（不稳定部分（11–16％））。尽管土壤P大部分保持在较少的可用部分中，但通过从农田和原地获得的土壤P数据之间的差异获得的遗留P为一段时间内的P积累估算提供了一种有用的方法，非常接近于预测的P输入/输出会计。腕带比其他覆盖作物回收的磷更多，随时间增加了不稳定的磷（5–20％）和所有有机磷的比例（10–25％）。