Browsing by Subject "Acid soils"
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- ItemImproving Grain Legume Yields in Gurué District, Mozambique Using Local Evate Rock Phosphate(2024-02) António Rocha; Ricardo Maria; Rogério Rafael; Job Fugice; Upendra Singh; Unasse Saide Uaite; Kim Falinski; Russell YostAcid, infertile reddish-brown soils characterize large amounts of central Mozambique. Few of these soils are in food production representing a missed opportunity for agricultural productivity and a missed alternative to improve the food security of the country. These soils are mainly depleted of macronutrients such as N, P and K. Low levels of soil nutrients such as calcium, phosphorus, and potassium limit crop growth. Therefore, while N can be obtained from the air by biological nitrogen fixation (BNF) and organic sources, P and K as well others (Ca and Mg) must be provided from rocks and minerals. Local agricultural amendments for acid, infertile soils such as limestone and rock phosphate exist but are unexploited. An experiment was conducted to assess the feasibility of using local Evate rock phosphate (~ 40.7% total P2O5) as a corrective to supply phosphorus. The rock phosphate was applied at rates of ~ 20, 40, 80 and 160 kg total P ha-1 . For a comparison, triple super phosphate was also added at four P levels (~0, 10, 20 and 40 kg P ha-1 ). A long growth cycle crop of pigeon pea (Cajanus cajan L., Mill sp. variety “ICAEP00020”) with a growth cycle of 190 days was used to assess effectiveness of the local rock phosphate. A pigeon pea grain yield of 1000 kg grain ha-1 was possible with an application of 80 kg ha-1 of total P added as Evate rock phosphate. By comparison 20 kg P ha-1 as TSP was needed to reach a maximum yield of pigeon pea grain. This ratio suggests that Evate rock phosphate was 25% as effective as TSP on a total P basis. This research suggests that the Evate rock phosphate can be an effective amendment that can enable or enhance food grain production on the acid, infertile upland soils of Central Mozambique. Whether for direct application for acid-tolerant crops on acid soils or processed into soluble fertilizer phosphate, the existence of such a valuable resource provides a great opportunity for improved local food crop production.
- ItemRelative Agronomic Effectiveness of Phosphate Rock Compared With Triple Superphosphate for Initial Canola, Wheat, or Ryegrass, and Residual Wheat in Two Acid Soils(2009) Suzette A. Smalberger; Sen H. Chien; Upendra Singh; Julio HenaoDirect application of phosphate rock (PR) may provide the essential phosphorus (P) nutrient for crop production in acid soils. However, the agronomic effectiveness of PR depends on several factors including PR reactivity, soil properties, and crop species. This greenhouse study investigated the effects of PR reactivity, soil pH, Al saturation, and crop species on the initial and residual relative agronomic effectiveness (RAE) of PR compared with water-soluble triple superphosphate (TSP) in two acid soils (Hartsells pH 4.8 and Hiwassee pH 5.4). Three PR sources, Tunisia, Mali, and Togo, representing high, medium, and low PR reactivity, respectively, were used. The soils were treated with P sources at 0, 25, 50, 100, 200, and 500 mg P kgj1 soil. Wheat, ryegrass, and canola were the test crops in the first season, and wheat was used as a residual crop after all three initial crops in the second season. Soil samples were collected for chemical analyses at 0 and 500 mg P kgj1 soil after the first crops. The initial RAE of PR for crop species followed: canola 9 ryegrass = wheat in the Hartsells soil and canola 9 ryegrass 9 wheat in the Hiwassee soil. However, the residual crop of wheat after wheat, wheat after ryegrass, and wheat after canola did not show any significant effect of previous crop. Among P sources, both initial and residual RAE followed: TSP 9 Tunisia PR 9 Mali PR Q Togo PR for all the crops and soils except for the initial canola crop grown in Hiwassee soil where all PR sources were as effective as TSP. In general, the RAE of PR in Hiwassee soil was higher than that of Hartsells because of the negative effects of soil acidity and Al saturation on crop growth in the Hartsells soil. A significant relationship between available P after first crops and residual wheat grain yield was found in the Hiwassee soil.
- ItemRelative Performance of Coated Blends, Granular Blends and Compound Fertilizers on Maize Yield(2022-11-30) Reda Ahmed; Genga Quintar ; Ngunjiri Mercy; Leonardus Vergutz; Wendt JohnMulti-nutrient fertilizers are becoming increasingly popular. Differences in relative crop response between blended and compound fertilizer forms have received little attention. This study was carried out to investigate the relative performance of a compound fertilizer, a blend formulated with coated micronutrients (zinc and boron), and a blend formulated with granular micronutrients. Yara MilaTM PowerTM compound fertilizer was used as the nutrient reference fertilizer, and two blends were formulated to apply the same amounts of nutrients per hectare. Both full and half rates of each fertilizer were applied. A randomized complete block design (RCBD) with four replications was employed at two sites in Bungoma county, Kenya using maize as a test crop. Ear-leaf analyses showed non-significant differences for most nutrients in most treatments within sites, with leaf N, K, S, B and Zn deficiency evident at both sites. Leaf deficiencies of Zn and B suggest that rates may not have been adequate for optimal production. Site 2 (pH 4.52) showed substantially lower ear-leaf nutrient concentrations compared with Site 1 (pH 5.14), particularly for Mg and Ca, which were also deficient in initial soil analysis at both sites. At Site 1, no significant differences were noted between the micronutrient coated blend, granular blend and compound, and yields were greatest at the full rate of fertilizer. At Site 2, the micronutrient coated blend gave significantly greater yields than the granular blend and the compound, and yields were not affected by fertilizer rate. We conclude that micronutrient-coated blends can be as effective or more effective than fertilizer compounds containing the same nutrient concentrations.
- ItemSeminar on Phosphate Rock for Direct Application(1979-12) IFDCThe IFDC Phosphate Program, established in 1974, focuses on three objectives: developing technology for efficient beneficiation of phosphate ores, identifying effective fertilizers for tropical and subtropical agriculture, and developing technologies for converting phosphate rock into fertilizers. The program aims to address the challenges posed by the depletion of easily accessible phosphate reserves and the need for more suitable fertilizers for small farmers in the developing world. Key activities include establishing a raw materials data file, researching beneficiation methods for low-quality ores, recovering phosphate slimes, and developing granulation and blending techniques for fertilizer production. The program aims to provide technical assistance, technology transfer, and manpower development to support sustainable agricultural practices in developing countries.
- ItemUse of Radioactive 32p Technique to Study Phosphate Rock Dissolution in Acid Soils(2002) G.L. Mullins; Sen H. Chien; Mahisarakul, J.A laboratory experiment was conducted to evaluate the dissolution of six sources of phosphate rock in two acid soils (Ultisols): a sandy soil and a red clay soil. Labile P was determined using the radioactive 32P technique for Pi extractable P and resin extractable P. Incubations were conducted for 0, 1, 2, 3, 4 and 5 weeks for 32P exchangeable technique, 0 and 5 weeks for Pi technique and 5 weeks for resin technique. Rates of PR were 0 and 400 mgP/ha. The results showed that labile P in the sandy soil decreased from 0-1 weeks for all the PRs except Hahotoe PR and Hazara PR's. Between 1 and 5 weeks labile P remained relatively constant. The ranking of labile P from PRs was: North Carolina = Kouribga > Matam > Hahotoe = Hazara> Patos de Minas. In the red soil, labile P from all PRs appeared to be relatively unchanged during the 0-5 week incubation. Pi extractable P in sandy soil showed no significant differences due to incubation time. In the red clay soil, there was a significant decrease in Pi-P extracted from soil mixtures with PRs after 5 weeks as compared to 0 weeks. Results of the Resin-extractable P in both sandy and red soils were in agreement with labile P as measured by 32P exchange technique.