Paulo Renato Perdigão Paiva

Dry matter production and nutrient accumulation after successive crops of lettuce, tomato, rice, and andropogongrass in a substrate with zeolite

SUMMARY Zeolites are hydrated crystalline aluminosilicate minerals of natural occurrence, structured in rigid third dimension net that can be used as slow release plant-nutrient source. The main objective of this study was to evaluate the effects of plant growth substrate under zeolite application, enriched with N, P and K, on dry matter yield and on nutrient contents in consecutive crops of lettuce, tomato, rice, and andropogon grass. The experiment was carried out in a greenhouse, with 3 kg pots with an inert substrate, evaluated in a randomized block design with three replications. Treatments consisted of four types of enrichment of concentrated natural zeolite: concentrated zeolite (Z) only, zeolite + KNO3 (ZNK), zeolite + K2HPO4 (ZPK) and zeolite + H3PO4 + apatite (ZP), and a control grown in substrate fertilized with a zeolite-free nutrient solution. Four levels of enriched zeolite were tested: 20, 40, 80, and 160 g/pot. Four successive crops were grown on the same substrate in each pot: lettuce, tomato, rice, and andropogon grass. Results indicated that N, P and K enriched zeolite was an adequate slow-release nutrient source for plants. The total dry matter production of above-ground biomass of four successive crops followed a descending order: ZP > ZPK > ZNK > Z.

Nutrient release by a Brazilian sedimentary zeolite

This report describes the characterization of a sedimentary occurrence from the Parnaiba Basin, Brazil, containing the zeolite stilbite intertwined with smectitic clay mineral. The head samples from different sites present a wide content range of the zeolitic phase – 15% to 50%. The use of simple separation techniques – conventional gravitic treatments – yields concentrates containing about 67% of the zeolitic component. Assays with the amendments of these concentrates with plant nutrients yield release rates matching those reported for similar commercial products.

Yield, Quality Components, and Nitrogen Levels of Silage Corn Fertilized with Urea and Zeolite

The zeolite and urea mixture may be use to improve nitrogen (N)–use efficiency of silage corn. The objective of this study was to evaluate dry-matter yield and nutritional levels of N of silage corn fertilized with urea and zeolite mixture. The experimental design was a 2 × 4 × 4 factorial randomized block design with three replications. Treatments included two types of stilbite zeolite (natural and concentrated), four levels of nitrogen (0, 50, 100, and 200 kg ha−1), and four ratios of zeolite (25%, 50%, and 100% of N level). Treatments were applied 60 days after planting with the topdressing fertilization. The use of concentrated (650 g kg−1 of stilbite) or natural (470 g kg−1 of stilbite) zeolite with urea increased silage corn dry-matter production and leaf N concentrations.

Crescimento e nutrição mineral do porta-enxerto limoeiro 'Cravo' cultivado em substrato com zeólita enriquecida com NPK

The main objective of this research was to evaluated the growth, dry matter production, leaf area, N, P and K levels and exportation and chlorophyll levels of Rangpur Lime (Citrus limonia Osbeck) grown in a substrate with NPK enriched zeolite. Rootstocks were cultivated during 93 days in 150cm3-dibble tubes containing composted organic substrate of cocopeat and vegetal coal (3:1) with zeolite addition. Treatments comprised 4 levels (0, 2.5, 5, 10 and 15 g per plant) of a NPK-enriched zeolite, which was a mix of H3PO4/apatite-zeolite (70%) and KNO3 - zeolite (30%). Results indicated that the supply of nutrients through the mineral zeolite enriched with NPK added to the organic substrate was a viable alternative for citrus rootstock production in protecting environment. The supply of 6,4 g of enriched zeolite significantly increased dry matter production, leaf area, height and steam diameter. These increases were 37,5% in relation to the control without zeolite. N, P and K foliar levels increased with zeolite enriched with NPK. Chlorophyll levels were related to N levels, pointed out to be a useful tool for Rangpur Lime nutritional status evaluation.

Concentração por flotação da apatita proveniente de rochas de filiação carbonatítica

The current processing study seeks to improve operations for the direct and reverse flotation of apatite originating from carbonatically-affiliated rocks to obtain an apatite concentrate in accordance with the phosphoric acid industry specifications. The direct flotation of apatite was carried out in two flotation phases, rougher and cleaner. The aim of direct flotation was to generate a product to feed the reverse flotation circuit of apatite. Reverse flotation was performed in three stages (rougher, cleaner and recleaner) and at pH 5.0, using phosphoric acid (H3PO4) as an apatite depressor. Summing up, the results of reverse flotation tests pointed out apatite recovery, which shows that the specific reagents used favored system selectivity. It was possible to obtain an apatite concentrate with 38.11% of P2O5, 50.98% of CaO, 1.07% of Fe2O3, 0.67% of MgO and ratio CaO/ P2O5 of 1.34.