Effects of Zeolite on Drought Resistance and Water–Nitrogen Use Efficiency in Paddy Rice

To reduce the negative effects of deficit irrigation on water and nitrogen (N) use, a pot experiment was conducted over two consecutive years to study the effects of zeolite (Z) on soil-water retention, water consumption, N distribution, and various soil nutrients under alternate wet–dry (AWD) irrigation. The results showed that Z significantly improved field capacity and reduced the number of ineffective tillers, thereby saving 5.8% and 12% water at the tillering and milky ripening stages, respectively. However, it could not offset its enhanced effect on evapotranspiration mainly due to a greater number of effective tillers promoted by Z addition during the jointing–booting and heading–flowering stages, and ultimately significantly increased total water consumption. AWD reduced rice grain yield, but Z significantly increased water and nutrient retention and, thus, increased water productivity by 8.9%. Although AWD increased N content in roots, it reduced total N uptake. Further, Z significantly increased N accumulation in roots and panicles and reduced N content in leaves and stems, thereby enhancing the N harvest index by 2.7%. Soil potassium, sodium, and calcium content significantly increased with Z addition, further affecting rice grain yield. In summary, zeolite increases the drought resistance of rice under AWD irrigation and increases water–nitrogen use efficiency.