Perceptions of Irrigation Water Management Practices in the Mississippi Delta

The Mississippi River Valley Alluvial Aquifer (MRVAA) is being depleted, and practices that improve water stewardship have been developed to reduce drawdown. This study assesses how Mississippi Delta producers changed their perceptions of these practices over time. The analysis employs data from two surveys carried-out in 2012 and 2014 of all Mississippi permittees who held an agricultural well permit drawing from the MRVAA. Focusing on water-saving practices, this study found that producer perception of the usability of flowmeters improved over time. About 80% and 90% more producers growing corn and soybeans, respectively, felt that computerized hole selection was highly efficient. In 2014, 38% of corn and 35% of soybean producers believed that shortened furrow length was a highly efficient practice—up from 21% in corn and 24% in soybean producers in 2012. Approval of irrigation automation, moisture probes, and other irrigation technology rose from 75%of producers in 2012 to 88% by 2014. Favorability toward water-saving practices increased overall between the survey years.

Amplified warming induced by large-scale application of water-saving techniques

Large-scale agricultural activities can exacerbate global climate change. In the past three decades, over 5 Mha of cultivated land have been equipped with Water-Saving Techniques (WST) in Northwest China to cope with water scarcity. However, the effect of WST on local climate and its mechanisms are not yet understood. Here we quantified the local climatic effect by comparing temperature and humidity at controlled and irrigated sites before and after the large-scale implementation of WST. Results show that the substantial reduction in irrigation water use has led to an average increase of 0.3°C in growing-season temperature and reduced relative humidity by 2%. Near-surface air temperature responds nonlinearly to percentage area of WST and a threshold value of 40% is found before any noticeable warming effect over the study area. Moreover, it is found that regions with relatively humid climates respond more significantly to WST. This study reveals the mechanism of WST on near-surface climate and highlights the importance of incorporating this feedback into sustainable water management and land-surface models for assessing the impact of irrigated agriculture on regional climate change.

Effective Use of Water in Crop Plants in Dryland Agriculture: Implications of Reactive Oxygen Species and Antioxidative System

Under dryland conditions, annual and perennial food crops are exposed to dry spells, severely affecting crop productivity by limiting available soil moisture at critical and sensitive growth stages. Climate variability continues to be the primary cause of uncertainty, often making timing rather than quantity of precipitation the foremost concern. Therefore, mitigation and management of stress experienced by plants due to limited soil moisture are crucial for sustaining crop productivity under current and future harsher environments. Hence, the information generated so far through multiple investigations on mechanisms inducing drought tolerance in plants needs to be translated into tools and techniques for stress management. Scope to accomplish this exists in the inherent capacity of plants to manage stress at the cellular level through various mechanisms. One of the most extensively studied but not conclusive physiological phenomena is the balance between reactive oxygen species (ROS) production and scavenging them through an antioxidative system (AOS), which determines a wide range of damage to the cell, organ, and the plant. In this context, this review aims to examine the possible roles of the ROS-AOS balance in enhancing the effective use of water (EUW) by crops under water-limited dryland conditions. We refer to EUW as biomass produced by plants with available water under soil moisture stress rather than per unit of water (WUE). We hypothesize that EUW can be enhanced by an appropriate balance between water-saving and growth promotion at the whole-plant level during stress and post-stress recovery periods. The ROS-AOS interactions play a crucial role in water-saving mechanisms and biomass accumulation, resulting from growth processes that include cell division, cell expansion, photosynthesis, and translocation of assimilates. Hence, appropriate strategies for manipulating these processes through genetic improvement and/or application of exogenous compounds can provide practical solutions for improving EUW through the optimized ROS-AOS balance under water-limited dryland conditions. This review deals with the role of ROS-AOS in two major EUW determining processes, namely water use and plant growth. It describes implications of the ROS level or content, ROS-producing, and ROS-scavenging enzymes based on plant water status, which ultimately affects photosynthetic efficiency and growth of plants.

Water Utilization Status and Water Saving Awareness Investigation

In this study, water utilization status and water saving awareness investigation were analyzed through a survey in Gwangju Metropolitan City. Consequently, it was observed that most water is wasted when showering and doing laundry. Therefore, it is necessary to supply water-saving washing machines and dishwashers along with water-saving devices. A total of 64% of the respondents conserve water in their daily lives, and the reasons are worries about the future and economic reasons. Water saving is not practiced because it is unfamiliar or uncomfortable. Therefore, methods are necessary to save water without inconvenience in daily lives. It is judged that the results of this study can be used to establish strategies for water demand management.

Reduced Water Use in Barley and Maize Production Through Conservation Agriculture and Drip Irrigation

The Mexican Bajío region is the country's main barley (Hordeum vulgare) producing area. Barley is commonly produced during the dry autumn–winter season using furrow irrigation with ground water, following which rainfed maize (Zea mays) is grown in the spring–summer season using supplementary irrigation. Ground water levels in the region are steadily dropping, and the introduction of water-saving technologies in agriculture is urgently required. Drip irrigation can reduce water use but is costly. Conservation agriculture—the combination of minimal tillage, permanent soil cover and crop diversification—might reduce water use, but studies in irrigated systems are scarce. We compared water use and grain yield in tillage-based conventional agriculture and conservation agriculture, both with furrow irrigation and drip irrigation, in a 3-year (six growing seasons) barley-maize field experiment. Additionally, side-by-side demonstrations of conventional and conservation agriculture were installed simultaneously in farmers' fields and yields, water use and fuel use were recorded. In the field experiment, yields did not differ significantly between production systems, but irrigation water use was on average 17% lower in conservation agriculture than in conventional agriculture, ~36% lower with drip irrigation compared with furrow irrigation in conventional tillage, and 40% lower with drip irrigation and conservation agriculture combined compared with conventional agriculture with furrow irrigation. Water use reductions differed strongly between years, depending on weather. The water saving through conservation agriculture in farmers' fields was similar to the water saving in the controlled experiment with about 17%. Additionally, in farmer's fields conservation agriculture reduced greenhouse gas emissions by 192 kg CO2 ha−1 and improved soil health. The implementation of conservation agriculture would be a cost-effective method to reduce water use in the barley-maize production system in the Mexican Bajío, while simultaneously reducing greenhouse gas emissions.