Azolla Fern in Mwea Irrigation Scheme and Its Potential Nitrogen Contribution in Paddy Rice Production

Oyange, Wilson Agembo; Chemining’wa, George N.; Kanya, James I.; Njiruh, Paul Nthakanio

doi:10.5539/jas.v11n18p30

Cited by 9 publications

(10 citation statements)

References 9 publications

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“…The Mwea region is located 100 km north of Nairobi and is a flat area extending to the south of Mount Kenya, the nation's highest mountain (5199 m). With an altitude of around 1159 m, the average annual temperature in the Mwea region is ~22 • C, and the average annual rainfall is ~930 mm [23]. The local climate is tropical with two rainy seasons: a long rainy season from March to May and a short one from October to November [24].…”

Section: Study Areamentioning

confidence: 99%

The Value Chain of Locally Grown Japonica Rice in Mwea, Kenya

et al. 2021

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In Kenya, there is an urgent need to strengthen domestic rice production to improve food security. To achieve this, it is necessary to develop a value chain of competitive rice varieties that creates new value over and above that of conventional varieties. In this study, we focused on locally grown japonica rice produced in the Mwea area, which has recently begun to be distributed in Nairobi. Through interviews with Japanese restaurants, Japanese food stores, and consumers as well as interviews with stakeholders in the value chain the market price, consumer acceptability, and profitability of locally grown japonica rice were determined. We evaluated the value chain of locally grown japonica rice based on the interaction between the potential demand and a value chain analysis and examined improvement measures to establish the value chain. The results showed that 76% of consumers who eat staple foods other than rice rated locally grown japonica rice as “very good” or “good”, indicating that it may be acceptable to those who do not usually eat rice. The net profits for locally grown japonica rice were higher than those of conventional rice at the production, processing, and distribution stages, which is an advantage for producers and demonstrates that the elimination of middlemen is effective and highly profitable for each stakeholder. In contrast, the consumer price of locally grown japonica rice was higher than that of conventional rice, indicating that some challenges remain to be overcome. Our estimation approach will allow further study of target values such as selling price in other desired value chains. Together, our findings suggest the potential of the locally grown japonica rice value chain to contribute to the strengthening of domestic rice production.

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Section: Study Areamentioning

confidence: 99%

The Value Chain of Locally Grown Japonica Rice in Mwea, Kenya

et al. 2021

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“…Ito and Watanabe (1985) showed that early incorporation of Azolla in the soil increases nitrogen availability. Farmers in Mwea incorporate Azolla in the soil during weeding as a management strategy (Oyange et al, 2019). Considering the abundance of Azolla in Mwea paddies, its integration with inorganic fertilizers and timely incorporation in the soil can help reduce the cost of inorganic fertilizers and consequently the cost of paddy rice production.…”

Section: Introductionmentioning

confidence: 99%

Effect of time of Azolla incorporation and inorganic fertilizer application on growth and yield of Basmati rice

Oyange¹,

Cheminingâ€TMwa²,

Kanya³

et al. 2020

Afr. J. Agric. Res.

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Azolla tissue contains 5% N, which is slowly released into the soil upon decomposition. Timing of incorporation is therefore important for maximum benefit to a crop. The effect of time to incorporate Azolla biomass on growth and yield of rice was investigated in Mwea-Kenya. Treatments consisted of 7.5 t ha-1 Azolla biomass applied at transplanting, 7.5 t ha-1 Azolla applied at 21 days after transplanting (DAT) and 30 kg N ha-1 inorganic N applied in splits at O, 21 and at 55 DAT. There were control treatments without Azolla and without inorganic N application. The treatments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Phosphorus and potassium were applied at 50 Kg ha-1 each as P 2 O 5 and K 2 O. Plant height and tiller numbers were recorded at 21 (rooting/tillering), 32 (tillering), 42 (maximum tillering), 60 (flowering) and 75 DAT (heading) while yield parameters were determined at physiological maturity (120 DAT). Data were analysed using SAS software and means separated using the least significant difference test (p≤0.05). Azolla incorporation at transplanting significantly enhanced panicle m-2 , grain weight and grain yield while incorporating it at 21 DAT only significantly enhanced panicle m-2. Higher environmental temperatures enhanced Azolla effect. The effect of Inorganic N significantly increased plant height, tiller number, grain weight and spikelets panicle-1. However, percentage grain filling was reduced. The effect of interaction between Azolla application and inorganic N was significant on spikelets panicle-1 and grain weight. Observations therefore indicate that the effect of Azolla on yield and yield components was more when incorporated at transplanting.

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“…The inorganic fertilizers that farmers mainly use in the MIS release mineral nitrogen in the form of NH 4 + , which is stable in ooded anaerobic environments. The nitrogen is usually applied in three splits whereby about 30% of the total nitrogen is applied as basal with the remaining amount applied in two equal splits at the active tillering and panicle initiation stage (Oyange et al 2019). Soil aeration due to draining of water cause changes in nitrogen from NH 4 + to NO 3 -; the latter nitrogen form is unstable under ooded anaerobic conditions and can quickly be lost through denitri cation (Ishii et al 2011).…”

Section: B Macro-nutrientsmentioning

confidence: 99%

Multi-variate Analysis of the Soil Chemical Properties in the Mwea Irrigation Scheme, Kenya and its Implications on Agronomic Management

Menge,

Musila,

Kagito

et al. 2023

Preprint

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Sub-Saharan Africa is a net importer of rice with self-sufficiency rates of as low as 14% in countries such as Kenya. More 80% of the rice produced in the country is cultivated in the Mwea irrigation scheme. Productivity in the irrigation scheme declined from 5.6 ─ 6.0 t ha− 1 to 1.3 ─ 4.6 t ha− 1 between 1977 and 2018 that could be attributed to site specific nutritional deficiencies and /or toxicities rendering the generalized agronomic recommendations inapplicable in some areas. This study aimed to evaluate variability in soil chemical properties within the irrigation scheme, cluster areas with similar nutritional status and provide area-specific agronomic recommendations. Four hundred samples were collected from the five sections of the Mwea irrigation scheme and analyzed for total organic carbon, soil pH, macro nutrients, micro nutrients and exchangeable cations. Principal components (PC) 1 ─ 4 accounted for 72.2% of the total variability within the irrigation scheme. Four clusters were generated in a scatter plot between PC1 and 2 and there were significant differences among the clusters for all the elements evaluated except for Na. Soil pH, potassium and zinc levels were found to be below optimum while available phosphorus and iron were above the critical levels leading to deficiencies and /or toxicities. Based on the findings of cluster analysis and variability of each nutrient among the clusters, specific management strategies were suggested to guide in developing of a package of good agronomic practices to improve rice productivity in the irrigation scheme.

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Azolla Fern in Mwea Irrigation Scheme and Its Potential Nitrogen Contribution in Paddy Rice Production

Cited by 9 publications

References 9 publications

The Value Chain of Locally Grown Japonica Rice in Mwea, Kenya

The Value Chain of Locally Grown Japonica Rice in Mwea, Kenya

Effect of time of Azolla incorporation and inorganic fertilizer application on growth and yield of Basmati rice

Multi-variate Analysis of the Soil Chemical Properties in the Mwea Irrigation Scheme, Kenya and its Implications on Agronomic Management

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