Changes in GHG Emissions Based on Irrigation Water Quality in Short-Term Incubated Agricultural Soil of the North China Plain

A worsening water shortage is threatening the sustainable development of agriculture in the North China Plain (NCP). How to make effective use of inferior water resources and alleviate the impact of insufficient water resources on agricultural environments is one of the urgent problems in agricultural production. Although agriculture plays an important role in greenhouse gas (GHG) emissions, the effects of irrigation water quality on such emissions in the NCP are not clear. In this study, we used a short-term incubation experiment to test the effects of the irrigation water quality (underground water (UW), saline water (SW), and reclaimed water (RW)) and frequency (high (H) and low (L)) on regulating the soil GHG emissions of the NCP. The results indicated that RW treatment increased the CO2 and N2O emissions by 15.00% and 20.81%, respectively, and reduced the CH4 uptake by 12.50% compared with the UW treatment. In addition, SW treatment decreased the CO2 and N2O emissions and CH4 uptake by 35.18%, 40.27%, and 20.09% against UW treatment, respectively. The high-frequency water added to the soil significantly increased the GHG emissions for all water qualities applied. Compared with UW, the global warming potential was significantly increased by RW_H and RW_L with 26.48% and 14.5% and decreased by SW_H and SW_L with 32.13% and 43.9%, respectively. Compared with the increase brought by reclaimed water, changing irrigation water sources from conventional groundwater to saline water (4 g L−1) will moderately reduce GHG emissions under the worsening water shortage conditions occurring in the NCP.

Evaluation of Soil and Irrigation Water Quality in Caohai Lakeside Zone

Due to the rapid population growth and over-application of fertilizers in the Caohai surrounding farmlands, controlling the non-point source pollution in the Caohai Lakeside Zone is significant for the local ecology balance and human health safety. A total of 54 soil and 24 irrigation water samples were collected in the Caohai Lakeside Zone to evaluate the current status of soil fertility and heavy metal pollution by measuring soil and water heavy metal content and soil physicochemical properties such as soil total nitrogen, total phosphorus, organic matter, and soil pH. These results showed that the total amounts of organic matter, nitrogen, phosphorus, potassium, and effective nutrient content in the Caohai Lakeside Zone were all at a rich level according to Chinese soil nutrient grade standard; the content of lead (Pb), chromium (Cr), cadmium (Cd), mercury (Hg), and arsenic (As) in the soil all exceeds the safety standard of Chinese classification of soil environmental quality assessment. In addition, the over-standard rates of Cd and Cr were 24.1% and 14.8%, respectively. On the whole, the comprehensive quality index (CQI) of the soil in the Caohai Lakeside Zone is 6.48, which is attributed to the heavy Cd pollution and the good soil fertility. The heavy metal content of the irrigation water met the requirements of irrigation water quality. It is feasible to use the irrigation water of Caohai Lake in the actual agricultural production process. Therefore, in terms of the comprehensive management and pollution control of Caohai, special attention should be paid to the control of Cd, Pb, As, and Hg pollution sources.

Development of an integrated irrigation water quality index (IIWQIndex) model

There are many irrigation water quality indices used to assess water suitability, despite some of their limitations. Hence, it is imperative to develop a water quality index to evaluate the irrigation water more accurately. This study has aimed to emerge an Integrated Irrigation Water Quality Index (IIWQIndex) using the sub-index and aggregated equations. This proposed index model was considered to be improved and updated in four aspects: the verified desirable and permissible value of parameters, maximum hazard class, used a modified rating system of parameters, and diversified parameters were considered. The proposed IIWQIndex model classified irrigation water into five categories, i.e., rejection, poor, moderate, good, and excellent. This model assessed two types of water to justify the model by categorizing the irrigation waters. The calculated results showed that the index values were 75.77 and 36.51, and the water category fell under ‘good’ and ‘rejected’ for the calcite (Ca-HCO3) and sodic (Na-Cl) water, respectively. Besides, this index model satisfactorily evaluated different types of water datasets of eight geographic locations in the world. The study illustrated that the IIWQIndex evaluated values and water categories were rational and exhaustive to predict the suitability of irrigation water.

Development of an Irrigation Water Quality Database to Identify Water Resources and Assess Microbiological Risks During the Production of Fresh Fruits and Vegetables

An Irrigation Water Quality Database was developed to help assess the microbiological quality of irrigation water used in fruit and vegetable production in 15 counties in New York (NY) State. Water samples from Tennessee (TN) were also included in the database. Four water quality parameters, quantified generic Escherichia coli, specific conductance, pH, and turbidity, were tested. Ground, reservoir, and running water were sampled over 2 years (2009 and 2010), covering three seasons each year (spring, summer, and fall). TN data are for all three seasons in 2010 only. Overall in NY (254 total samples), ground water had a geometric mean of 1 most probable number (MPN)/100 ml, reservoir water had a geometric mean of 8 MPN/100 ml, and running water had a geometric mean of 52 MPN/100 ml. Overall in TN (63 total samples), ground water had a geometric mean of 1 colony forming unit (CFU)/100 ml, reservoir water had a geometric mean of 5 CFU/100 ml, and running water had a geometric mean of 38 CFU/100 ml. These values are all below the 126 MPN/100 ml United States Environmental Protection Agency's Ambient Water Quality Standards (AWQS) standard for fresh water. The presence of E. coli had very weak but sometimes statistically signficiant correlatation with water specific conductance, pH, and turbidity, depending on the water source but the r-squared effect was not strong enough to make the other measurements a substitute for testing specifically for E. coli in water.

Quality Assessment of Groundwater of Barind Area, Bangladesh using Integrated Hydrochemical Method

The study was conducted for assessing water quality for drinking and irrigation purposes of groundwater sources. Total 50 water samples were collected from different locations of Nachol and Niamatpurupazilla of Chapainawabgonj and Naogaon district in January 2019 and January 2020. Water quality parameters like pH, electrical conductivity (Ec), iron (Fe), manganese (Mn), calcium (Ca), magnesium (Mg), zinc (Zn), copper (Cu), sodium (Na), potassium (K), total hardness (TH), alkalinity, sulphate (SO4), nitrate (NO3), nitrite (NO2), ammonia (NH4), phosphate (PO4), chloride (Cl), dissolved oxygen (DO), and total dissolved solids (TDS) were analyzed in the laboratory. All the analyzed parameters were compared with national and international drinking and irrigation water quality standards to understand the overall groundwater quality status of the study area. The study showed that the water samples of almost all the locations were suitable for consumption and irrigation.