Organomineral phosphate fertilization in millet in sandy soil

ABSTRACT Evaluation of fertilizers is an important premise, given the need for knowing new alternative sources to increase the efficiency in the use of nutrients, especially phosphorus. The objective of this study was to evaluate the growth of millet cultivated in sandy soil under phosphorus doses and sources. The experiment was carried out in a greenhouse, in Sobral, CE, in soil with low phosphorus concentration in the randomized block experimental design, with two sources (monoammonium phosphate - MAP and organomineral fertilizer prepared with MAP and organic compost of waste from small ruminant production - OMF) and four doses of P2O5 (35, 70, 140 and 210 kg ha-1), plus an additional treatment without phosphate fertilization, with three replicates, conducted in the second half of 2015. The variables measured were dry mass production, phosphorus accumulation in the plant and agronomic, physiological and recovery efficiencies. Evaluations were carried out in two cuts in millet plants(65 and 110 days after germination). The data were subjected to analysis of variance, followed by t-test for the sources and regression analysis for the doses, in addition to the Dunnett’s test to compare the phosphate fertilization with the control. In the first cut, it was observed that even at low doses of P2O5 (35 kg ha-1of P2O5), the biomass increases compared to the control. Increment in phosphorus doses increased the accumulation of this nutrient in millet plants. Considering the total accumulated in the two cuts of millet, the organomineral fertilizer promoted higher nutrient content compared to monoammonium phosphate from 127 kg ha-1 of P2O5.

摘要：鉴于亟需开发新型替代肥源以提升养分（尤其是磷素）利用效率，肥料肥效评价是一项至关重要的前置工作。本研究旨在评估不同磷素用量与肥源条件下，砂质土栽培粟的生长表现。试验于巴西塞阿拉州索布拉尔的温室中进行，供试土壤磷素浓度偏低，采用随机区组试验设计，设置2种磷肥源：磷酸一铵（monoammonium phosphate, MAP）、以及由磷酸一铵与小反刍家畜生产废弃物堆肥制备的有机无机复混肥（organomineral fertilizer, OMF）；4个P₂O₅用量梯度：35、70、140、210 kg·ha⁻¹，另设1个不施磷肥的对照处理，共3次重复，试验于2015年下半年开展。测定指标包括植株干物质产量、植株磷素积累量以及农艺效率、生理效率与养分回收效率。分别在粟出苗后65天和110天进行两次刈割采样。对数据进行方差分析后，针对肥源开展t检验、针对磷素用量进行回归分析，同时通过邓尼特检验（Dunnett’s test）比较各施磷处理与对照的差异。第一次刈割结果显示，即便施用低用量P₂O₅（35 kg·ha⁻¹），植株生物量仍较对照显著提升；提高磷素用量可增加粟植株内磷素的积累量。综合两次刈割的总磷素积累量来看，当P₂O₅用量达到127 kg·ha⁻¹及以上时，有机无机复混肥（OMF）的磷素积累效果优于磷酸一铵（MAP）。