Novel water- and fertilizer-management strategy: Nutrient-water carrier

摘要

A novel waterand fertilizer-management strategy has been developed in the study, which was called nutrient-water carrier. The nutrient-water carrier (NC) was prepared from N, O-carboxymethyl chitosan (NOCMC), acrylic acid (AA) and polyphosphate urea (PDUP) by solution polymerization. The nutrients content of NC was more than 70%, and it showed excellent water-retention and slow-released capacity properties. The optimal superabsorbent sample with excellent water absorbency (791.26 g/g) was obtained under the condition: 75% of AA neutralized, 10 wt% NOCMC, 5 wt% PDUP, 0.6 wt% APS, 0.05% MBA to AA weight, reaction at 70 degrees C for 2.0 h. After loading 25 wt% PDUP to AA weight into the polymer network, the swelling degree (SD) of optimal NC arrived 482.59 g/g. FTIR, SEM, EDS and TG were used to characterize the structure and performance of optimal NC. Results illustrated that the semi interpenetrate structure (semi-IPN) was constructed by the incorporation of linear PUDUP into the superabsorbent network, and the NC could dramatically enhance the water holding capacity of sandy loam, six-folders than without NC. In addition, the application of NC in sandy loam soil had a positive synergistic effect on the root length and seedling height of maize. Furthermore, the slow-released behavior for N, P and K was investigated. All the facts indicated that the NC could improve nutrients efficiency, prolong the period of fertilizer release, decrease irrigation frequency and address environmental pollution, which was expected to be widely used in semi-arid and arid areas.(c) 2021 Elsevier Ltd. All rights reserved.