ABSTRACT

Phosphorus (P) deficiency is a major yield constraint for lowland rice production in the tropics. As P-fertilizer resources are finite, alternative fertilizer management is needed for sustainable rice production. We examined whether farmyard manure (FYM), a major nutrient source for smallholder farms, can overcome issue in typical P-deficient lowlands in the central highlands of Madagascar. A multi-location trial in sites varying in altitude and soil P availability, clarified that the effect of both FYM and mineral P fertilizer application on grain yield greatly increased at higher elevation and when the soil oxalate-extractable P content was <100 mg kg⁻¹. The yield increase was attributable to improved grain fertility, probably because FYM and mineral P applications decreased days to flowering and avoided low temperatures at late growth stages. Nutrient uptake assessment clarified that despite its relatively low P content, FYM had an equivalent effect on plant P uptake to those of mineral P fertilizer. We concluded that FYM application was effective in low-P availability soils at high altitude, as alternative of mineral P fertilizer. Further monitoring is required to assess the effect of consecutive FYM use on grain yield and plant nutrient uptake in the context of cold stress induced by P deficiency.

摘要

磷（P）缺乏是热带低地水稻生产的主要产量限制因素。由于磷肥资源有限，可持续水稻生产需要替代肥料管理。我们研究了农家肥 (FYM) 作为小型农场的主要营养来源，能否克服马达加斯加中部高地典型缺磷低地的问题。在海拔和土壤磷可用性不同的地点进行的多地点试验表明，在较高海拔和土壤可提取的草酸磷含量 <100 mg kg 时，施用 FYM 和矿物磷肥对谷物产量的影响大大增加^{- 1}. 产量增加归因于谷物肥力的提高，可能是因为 FYM 和矿物磷的施用减少了开花天数并避免了生长后期的低温。养分吸收评估表明，尽管 FYM 的磷含量相对较低，但其对植物磷吸收的影响与矿物磷肥的影响相同。我们得出的结论是，作为矿物磷肥的替代品，FYM 施用在高海拔低磷有效性土壤中是有效的。需要进一步监测以评估在缺磷诱导的冷胁迫背景下连续使用 FYM 对谷物产量和植物养分吸收的影响。