Attapulgite application improves maize yield, water, and fertilizer utilization efficiency in newly cultivated sandy farmland in northwestern China

We determined the effects of attapulgite clay additions to sandy soils on maize yield and water-fertilizer use efficiency to evaluate a new method for enhancing productivity in newly-reclaimed farmlands in the oasis. The 2-year field trial included six treatments: no fertilizer, single fertilizer application (N–P2O5–K2O at 320–240–200 kg·ha−1), and combined applications of different amounts of attapulgite clay and fertilizer (attapulgite powder at 1500, 3000, 6000 kg·ha−1), 20% fertilizer reduction (256–192–160 kg·ha−1) and attapulgite powder at 6000 kg·ha−1. The results showed that maize yield increased by 4.9–14.9% and above-ground biomass increased by 6.1–32.3% with the application of 1500, 3000, and 6000 kg·ha−1 of attapulgite powder compared with the single application of fertilizer. With a combined application of a 20% reduction in fertilizer and 6000 kg·ha−1 attapulgite powder, maize yield increased by another 6.6%. Maize irrigation-water productivity (MIWP) increased by 0.03–0.13 kg·m−3, and nitrogen use efficiency (NUE), agronomic efficiency (AEN) and partial productivity factor of nitrogen (PFPN) increased by 10.8–54.0, 15.5–49.5, and 4.6–14.8%, respectively, compared with no attapulgite application. The contribution rate of fertilizer to maize yield increment improved by 10.0–30.1% with attapulgite application. The attapulgite clay application increased the field water capacity of sandy soils, nutrient retention in the 0–40 cm soil layer, and reduced nutrient leaching losses to deeper soils, thus improving water-fertilizer use efficiency. In Linze County, the abundant reserves of attapulgite clay may be used as a regular application in sandy farmlands in newly-reclaimed oases for a new promising way to rapidly improve sandy soil structure, enhance water-fertilizer use efficiency, and increase crop yields.