The long-term use of sewage to irrigate farmland will increase the content of heavy metals in the soil and cause soil pollution. Heavy metal pollution in soils will restrict the sustainable development of local agriculture and will have a negative impact on the ecological environment. In this paper, the irrigation areas using domestic sewage, mixed sewage and industrial sewage as an irrigation water source for many years have been selected as the research objects, and the content of the heavy metals lead (Pb), copper (Cu), zinc (Zn) and cadmium (Cd) in the soil with the depth of 0-20cm, 20-50cm and 50-80cm of three kinds of sewage irrigation areas are assessed using single factor pollution index method and Nemerow comprehensive index method, and the potential ecological risks of heavy metals in the soil are assessed using Hakanson ecological risk index method. The results show that the content of heavy metals Pb, Cu, Zn and Cd in different depths of the three sewage irrigation areas does not exceed the national standard limit, and the heavy metal pollution grade in the soil belongs to the safety grade, indicating that the content of heavy metals in the soil has not reached the alert level. The potential ecological risks of heavy metals in the soil show minor ecological risks judging from single indexes, while Cd shows that the ecological risks are at a strong level. Judging from the comprehensive potential ecological risk index, the potential ecological risks of the heavy metals in the study area is minor in graded, but the heavy metals in the soil of the mixed sewage irrigation area and the industrial sewage irrigation area have a moderate grade of potential ecological risks at the depth of 50-80 cm. Therefore, although the content of the heavy metals in the soil of the three kinds of sewage irrigation areas in the study area is safe, the potential ecological risk of Cd is quite high, which should be paid attention to.

Global warming is the most significant environmental issue that causes the utmost concern for researchers and scientists. Furthermore, impacts recorded include the potential for drought and the reduction of soil ability to support biomass production, subsequently posing a significant threat to agriculture. Moreover, vegetation density is known to support microorganism activities actively, and its analysis requires remote sensing techniques, involving normalized differential vegetation index (NDVI) and soil adjustment vegetation index (SAVI), associated with microbial content in the soil. Besides, the level recorded is assumed to have a strong correlation with soil fertility, which is a prerequisite for the development of vegetation cover. Hence, most of the research was conducted in fertile lands situated in the Ungaran, Merbabu, and Telomoyo volcanic areas. The results show the absence of a positive correlation between soil fertility and the number of microorganism’s present, although the association with vegetation cover is relatively low.

The textile industry occupies a significant hold on the global economy. This substantial industry often generates a large volume of effluents exceeding the permissible limit of discharge in the different regions of the world. Therefore, textile effluents act as pollutants altering the natural composition of various components of the environment. This paper discusses the impact of textile-based pollutants on agriculture including plants, soil, water and fisheries. The observed result is significant because textile effluents exert a widespread negative impact on the respective respondents, though plants show few positive effects. Prior treatment of textile wastewater is necessary before applying it to the soil, as there is a possibility of affecting the plant ecosystem via soil media. Plants are benefitted in terms of germination and growth, due to irrigation by textile effluents with proper dilution. The physical and biochemical properties of water streams along with aquatic organisms are impacted by these specific discharges, leading to even severe deterioration of particular living creatures. Pollutants released from various steps of textile processing have adverse effects on the environment, disturbing the food chain, ecosystem, and overall ecological balance.

The thesis is aimed to provide a reference for the sustainable utilization of farmland soils along the Wuma River, an upstream tributary of the Chishui River in Guizhou Province. Geo accumulation index method, Nemero comprehensive pollution index method, and potential ecological hazard index method were used based on the experimental data for analyzing and evaluating the heavy metal pollution status of farmland soil along Wuma River. The results showed that: (1) The contents of heavy metals Ni, Cu, Zn, Pb and Hg in farmland soil exceeded the soil background values of 9.82%, 47.80%, 13.72% and 76.06% in Guizhou Province, respectively, but did not exceed the standard limit class II based on the environmental quality. (2). The pollutants of Pb and Zn in the research area mainly come from mineral exploitation, waste residue accumulation, and transportation. The enrichment of Cr and Cu may originate from the domestic garbage dumping and incinerated waste by residents along the coast and irrational agricultural activities. The main contents of Cd, As and Hg come from soil geochemistry. (3) The ranking of accumulations of eight heavy metals was IPb>IHg>ICu>INi>IZn>ICr>IAs>ICd, among which Pb was non-moderately polluted and the remaining heavy metals were at the clean level; Nemero comprehensive pollution index showed that As, Cr, Zn, and Ni were mildly polluted, while Pb, Hg, and Cu were moderately polluted. The ranking of potential ecological risk levels for the eight heavy metals was Hg, Pb, Cu, Ni, As, Cd, Cr, Zn. The overall ecological risk level is mild.