Understanding the effects of irrigation regime and soil texture on potassium-use efficiency (KUE) of rice (Oryza sativa. L) is essential for improving rice productivity. In this regard, experiments were conducted from July to October in 2016 and 2017 by using a randomized complete block design in a factorial arrangement with four replications. The rice plants were grown in three soils, with clay contents of 40%, 50%, and 60%, which were marked as S _(40%), S _(50%), and S _(60%), respectively. For each soil type, irrigation regimes, namely, R _{(F, S100%)}, R _{(F, S90%)}, and R _{(F, S70%)}, were established by setting the lower limit of irrigation to 100%, 90%, and 70% of saturated soil water content, respectively, and the upper limit of irrigation with 30 mm of flooding water above the soil surface for all irrigation regimes. Results showed that the responses of the roots and shoots and the potassium accumulation (KA) and KUE of rice were significantly affected by the water regime and soil texture. In the same irrigation regime, increasing the soil clay content improved the K utilization of rice. Under the same soil type, R _{(F, S100%)} was the optimal water management practice for growing rice. The R _{(F, S100%)} S _(60%) treatment presented the highest KUE, which was 56.4% in 2016 and 68.1% in 2017. The R _{(F, S70%)} S _(40%) treatment showed the lowest KUE, which was 13.8% in 2016 and 14.9% in 2017. These results enrich knowledge regarding the relationship among soil, water, and rice, and provide valuable insights on the effect of irrigation regime and soil texture on the KA and KUE of rice.

Rice is one of the most important food crops in China and is also the largest user of agricultural water. Experiments were conducted for two consecutive years at two locations of Jiangsu province to study the effect of four irrigation methods with four replications (shallow water irrigation (FSI), wet-shallow irrigation (WSI), controlled irrigation (CI), and rain-catching and controlled irrigation (RCCI)) on drainage, rainwater utilization rate, pollutant load of N and P, irrigation water, grain yield, and water use efficiency. The results show that FSI treatment used the largest irrigation amount, which is significantly higher than the other three irrigation methods, but the southern part of Jiangsu province especially Nanjing and riverside areas are relatively rich in water resources. It can be seen from our findings that FSI and RCCI are the best irrigation methods in Nanjing area to get a higher yield. However, the yield of CI treatment varies greatly; the annual and seasonal yield changes of CI treatment are higher than those of other treatments; and the risk of yield reduction is greater. Thus, considering water saving and high efficiency, RCCI is a better irrigation strategy than FSI. Combined with the following analysis, it can be seen that RCCI irrigation treatment has less nitrogen and phosphorus pollution load with no significant difference in yield in Lianshui and in 2017 in Nanjing area. Therefore, RCCI is more suitable for irrigation in Lianshui and similar areas.

In the present study, the effect of buried straw (two levels; M_S; buried straw layer and M_N; no straw layer), nitrogen fertilizer (two levels: F_H, 120 kg ha⁻¹ and F_L, 80 kg ha⁻¹), and deficit drip irrigation with irrigation frequency of 2 days (two irrigation regimes: I₅₀; 50% and I₃₀; 30% of evapotranspiration) was investigated on a greenhouse-grown leafy cabbage for two consecutive seasons. The results indicated that in both the seasons, T₅ (M_NF_HI₅₀) gave higher yield when compared to all other treatments but it also utilized more water and fertilizer. On the other hand, with a 5–10% decrease in yield comparing to T₅ (M_NF_HI₅₀), T₂ (M_BSF_LI₅₀) and T₄ (M_SF_LI₃₀) saved 33% of fertilizer. T₄ (M_BSF_LI₃₀) also gave the highest water and fertilizer use efficiencies when compared to all other treatments. However, it was clearly noted that T₄ (M_SF_LI₃₀) treatment could save water and nitrogen without a significant decrease in fresh yield of Chinese cabbage. Hence, T₄ (M_sF_LI₃₀) is the recommended strategy to manage water and nitrogen fertilizer for getting optimal leafy cabbage plant growth and yield.