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

Alberto C De Campos Bernardi,Fernando De Souza Barros,Carlos Guarino Werneck,Patrick Gesualdi Haim,Marisa Bezerra De Mello Monte,Paulo Renato Perdigão Paiva

doi:10.1590/s0100-06832010000200017

Abstract

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.

Highlights

Zeolite minerals are hydrated aluminosilicates of alkali or alkaline-earth metals, structured in a threedimensional rigid crystalline network, formed by tetrahedral AlO4 and SiO4, whose rings join in a system of canals, cavities and pores
The homoionic material was dispersed again in solutions containing 1.0 mol L-1 H3PO4 (ZP), 0.5 mol L-1 KNO3 (ZNK) or 1.0 mol L-1 K2HPO4 (ZPK) at a weight proportion of 1:40, and these solutions were stirred for 24 h at room temperature, centrifuged, filtered and dried at 100 oC
Lettuce dry matter (DM) yields were highest under applications of 13 and 9.9 g/pot of zeolite enriched with H3PO4 + apatite (ZP) and KNO3 (ZNK), respectively, at levels of 51.1 and 89.1 g/pot (Figure 1a)

Summary

Introduction

Zeolite minerals are hydrated aluminosilicates of alkali or alkaline-earth metals, structured in a threedimensional rigid crystalline network, formed by tetrahedral AlO4 and SiO4, whose rings join in a system of canals, cavities and pores. These minerals are characterized by the ease of retaining and releasing water and exchanging cations without structural changes (Mumpton, 1999; Kithome et al, 1999) and can potentially be used in field or substrate cultivation (Harland et al, 1999). Zeolites improve efficiency of water use, by increasing soil water holding capacity and water availability to plants (Xiubin & Zhanbin, 2001; Bernardi et al, 2009)

Objectives

Methods

Results

Conclusion