The large amount of nitrogen application on the North China Plain has caused a serious negative impact on the sustainable development of regional agriculture and ecological environmental protection. Our aim was to explore the effects of nitrogen fertilization rate and groundwater depth on growth attributes, soil-water and soil-fertilizer contents, and the winter wheat yield. Experiments were carried out in micro-lysimeters at groundwater depths of 60, 90, 120, and 150 cm on the basis of 0, 150, 240, and 300 kg/ha nitrogen fertilization rates in the growth season for winter wheat. Results showed that plant height, leaf area index, soil plant analysis development, and yield without nitrogen application increased significantly with increases in groundwater depth. The optimal groundwater depths for growth attributes and yield were 60–120 cm and tended to be shallower with added nitrogen application. Soil moisture was lowered significantly with groundwater depth, adding a nitrogen application reduced soil moisture, and excessive nitrogen input intensified soil drought. Nitrate-N accumulation at the 120–150 cm depths was significantly higher than that at the 60–90 cm depths, and a 300 kg/ha (traditional nitrogen application rate) treatment was 6.7 times greater than that of 150 kg/ha treatment and increased by 74% more than that of the 240 kg/ha treatment at 60–150 cm depth. Compared with the yield of the 300 kg/ha rate, the yield of the 240 kg/ha rate had no significant difference, but the yield increased by 3.90% and 11.09% at the 120 cm and 150 cm depths. The growth attributes and yield of winter wheat were better, and the soil nitrate-N content was lower, when the nitrogen application rate was 240 kg/ha. Therefore, it can be concluded that nitrogen application can be reduced by 20% on the North China Plain.

As the world economy and society have developed quickly, the amount of farmland soil pollution has become alarming, which has seriously threatened global food security. It is necessary to take effective measures on the moderately contaminated soil to produce high-quality food and to protect food security worldwide by effective use of land resources. Our experimental design was to study the changes in soil physicochemical properties and tomato yield and quality indicators by irrigating tomatoes on cadmium-contaminated soil with two different water qualities (reclaimed water irrigation: RW; tap water irrigation: TW) through drip irrigation devices. Tomato quality indicators were determined using plant physiological assays, as well as vitamin C (VC), total acidity (TA), protein content (PC), and soluble sugar content (SS). We tested five different types of cadmium-contaminated soils (less than 0.60 mg/kg, 0.60–1.20 mg/kg, 1.20–1.80 mg/kg, 1.80–2.40 mg/kg, 2.40–3.00 mg/kg) against RW and TW, and performed high-throughput sequencing of the soils to obtain environmental results for soil microbial diversity. The results reveal that compared with the TW condition, soil nutritional status was increased with the irrigated RW. The yield of the tomatoes increased by 52.03–94.03% than TW. The results of the study showed significant and highly significant relationships between tomato quality indicators (TA, SS, yield) and soil physical and chemical properties indicators (p < 0.01, 0.05). For instance, the RW increased the SOM by 6.54–12.13%, the TP by 0.48–24.73%, the yield of the tomatoes by 52.03–94.03% than TW, while the cadmium content did not show significant differences (p < 0.05), and the cadmium content did not increase the soil’s pollution level. Compared with TW treatment, RW treatment alleviated the inhibition of soil microbial diversity by cadmium and RW also increased its soil microbial diversity. The relative abundance of Proteobacteria, Gemmatimonadetes, and Bacteroidetes in the RW condition were higher than in the TW condition at different cadmium concentrations. In conclusion, RW improved the overall quality conditions of soil and the diversity of microbial communities, and did not aggravate the pollution degree of cadmium-contaminated soil, and affected the yield of tomatoes positively. RW can be an effective irrigation technique to reduce the use of clean water.

The growing population in conjunction with water scarcity forces us to search for alternative sources of irrigation water and integrate it with irrigation strategies for agricultural expansion to meet sustainable development objectives. For this purpose, a field experiment was conducted over three years (2017, 2018, and 2019) to investigate the effect of water quality (reclaimed water (RW) and freshwater (CW)), irrigation techniques (subsurface drip irrigation (SDI and Furrow irrigation (FUI)), irrigation methods (Full irrigation (FI) and alternate partial root-zone irrigation (APRI (70% ETc)), and their interactions on the fresh fruit yield (FY), irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE) of tomatoes. As well as evaluate the effects of these experimental factors on soil properties regard to electrical conductivity (EC), pH, and organic matter (OM) of Soil. The experiment was undertaken over three growing spring seasons in China. There were eight treatments in the experiment. For all three years, the yield, IWUE, and NUE values of all treatments under RW were high compared with the corresponding values under CW. The same occurred under SDI compared with FUI. Analysis of variances showed that there was no significant effect (P > 0.05) of water quality, irrigation technique, and irrigation methods on the soil EC, PH, and OM over the three years. In addition, there was no significant effect (P> 0.05) on the interaction between the experimental factors over the three years. In conclusion, the application of RW under SDI can result in saving CW and increasing productivity without any negative effect on the investigated soil properties, as well as, when RW-SDI is used in conjunction with APRI, it can result in increasing IWUE.