Pronounced effect of farmyard manure application on P availability to rice for paddy soils with low total C and low pH in the central highlands of Madagascar

Abstract

Farmyard manure (FYM)mixtures of animal droppings, crop residues, and fodder that are piled nearby homesteadsis a major nutrient source for smallholder farmers in Sub-Saharan Africa. However, its application effect has not been fully understood on typical P-deficient soils in tropics and in particular under anaerobic conditions. This study assessed the effect of FYM on irrigated rice in relation to soil propertiesoxalate-extractable P (P Ox), pH, and total C (TotC)that are important indicators of soil P deficiency in the region. The first pot experiment was conducted with a factorial combination of FYM (0 and 20 g kg-1) and mineral P (0 and 100 mg kg-1) applications using six paddy soils differing in the aforementioned soil properties. The second pot experiment was conducted in a factorial combination of FYM and mineral P using the isotope dilution technique. In both experiments, the effect of FYM application on biomass and P uptake of rice per P applied was nearly equivalent to that of mineral P and was greater in soils with lower TotC and lower pH with negligible effect of P Ox. The isotope tracing suggested that the FYM application might increase rice P uptake by solubilizing non-labile P pools in soils while mineral P was directly used by rice from labile P pools. The results indicated that the FYM should be most effective in soils with low TotC and low pH, and its application could enable the use of insoluble P pools in soils and enhance P uptake of rice under P-deficient and anaerobic conditions.

Amendment with Burkina Faso phosphate rock-enriched composts alters soil chemical properties and microbial structure, and enhances sorghum agronomic performance

“…Sorghum biomass and grain yields in the NK were 34 and 27% lower, respectively, than those in the NPK treatment, highlighting the importance of P nutrition in the studied environment, further confirming that P is a limiting nutrient in the soil. Many studies have highlighted the significant contribution of improved P uptake to crop grain yields in Africa 45 , 46 . In addition, we observed 25 and 23% decreases in biomass and grain yield, respectively, in the NK compared to in the P-COMP-SOIL.…”

Organic materials with high P and low C:P ratio improve P availability for lowland rice in highly weathered soils: Pot and incubation experiments

“…However, the strategy of adding extra C to the waterlogged soils was effective at some points during the incubation time and for the four soils in which the cellulose treatment surpassed the other treatments in solubilizing P. Similarly, the observation with the values in the control treatment were equal to or below those of the cellulose treatment in all soils, illustrating P solubilization due to amplified Fe reduction (Figure 2). This was most pronounced in S4, which could be attributed to its low C content (Mohammadi et al., 2009; Rakotoson and Tsujimoto, 2020; Vanden Nest et al., 2014). The rate of P solubilization due to OM2 addition was similar to that of cellulose addition, suggesting possible P immobilization due to a high C:P ratio, of around 386.5, and it is a low P content (1.84 g kg –1 ).…”

“…To date, a few of studies have focused on strategies to overcome the problem of P deficiency for lowland rice production, in particular by exploring the potential benefits of locally available organic resources. Although FYM application reportedly increases P availability in irrigated rice (Andriamananjara et al., 2016), Rakotoson and Tsujimoto (2020) found that the extent to which an increase in P availability led to an increase in biomass and yield was highly dependent on the soil characteristics. Farmers in SSA, including Madagascar, utilize extensive organic resources for fertilization, which affect crop production differently depending on various soil factors.…”

Phenotyping of a rice (Oryza sativa L.) association panel identifies loci associated with tolerance to low soil fertility on smallholder farm conditions in Madagascar

“…This is certainly the case in Madagascar where P deficiency is widespread, possibly due to high levels of P-fixing element such as iron (Fe), aluminum (Al) and/or oxyhydroxides [ 6 ]. This problem is exacerbated by the continual removal of organic residues and limited application of organic matter and/or fertilizer inputs [ 7 – 9 ]. The nutritional deficiency in soil could be alleviated through fertilizer application; however, the cost of fertilizers is often higher in SSA compared to other regions and therefore access to fertilizers is limited for resource-poor farmers in small scale farming systems.…”