Water management

Alternative cropping systems can sustain productivity and reduce impacts (e.g., excessive groundwater exploitation, nitrogen losses), but microclimate impacts in diversified systems are mostly unexplored. The aim of this study was to explore innovative cropping systems to reduce water use and nitrogen losses across different precipitation gradients. The well–calibrated Agricultural Production Systems sIMulator (APSIM) model and life cycle assessment were combined to analyze the water and nitrogen footprints of five alternative cropping systems, namely, spring maize–winter fallow (sM–F), winter wheat–summer fallow (WW–F), winter wheat–summer maize–winter fallow–spring maize (WW–M–sM), ryegrass–spring maize (R–sM) and winter wheat–summer maize (WW–M) in the North China Plain from 1980 to 2020. Our findings indicate the total water footprint (m³/10³ MJ) followed the order: WW–F (70) > WW–M (43) = sM–F (43) > R–sM (42) > WW–M–sM (41), while the total nitrogen footprint (g N–eq/10³ MJ) followed a different order: WW–F (423) > WW–M (335) > R–sM (246) > WW–M–sM (212) > sM–F (96). Green and blue water footprints were the primary contributors to the total water footprint for all cropping systems, but the proportion of grey water footprint increased across the precipitation gradient due to higher nitrate leaching. Ammonia volatilization and nitrate leaching were the primary factors contributing to nitrogen losses for all cropping systems, depending on drainage and N application. The most promising alternative cropping systems for sustaining groundwater use and mitigating nitrogen losses shift from sM–F and WW–M–F at dry sites to R–sM at wet sites. These findings highlight the importance of diversifying cropping system to the local climate, offering a scientific basis for green agriculture development across diverse regions in China.

Lu, Y., Xiao, D., Qi, Y. et al. Assessing water and nitrogen footprints of alternative cropping systems across the precipitation gradient of the North China Plain. Agron. Sustain. Dev. 45, 60 (2025). https://doi.org/10.1007/s13593-025-01061-y

In water-scarce subtropical regions, mango (Mangifera indica L.) is often grown under irrigation, which poses a threat in the context of changing climate. Researchers Durán et al. reviewed strategies based on deficit irrigation techniques to save water during drought or insufficient rain periods. They reckon that it is vital to redesign irrigation schemes and implement deficit irrigation strategies to save water but maintain yield while producing fruits with improved quality.

Although some chemical herbicides used by farmers in Martinique contaminate rivers, existing agroecological innovation is not always implemented to restore water quality. Scientists Della Rossa et al. show that each supply chain innovates independently of others with little exchange at a territorial scale. This situation adds to herbicide occurrence in watersheds. They believe territorial development should coordinate innovation for a sustainable transition of territories.

Cover crops provide many different ecosystem services, increasing soil carbon storage and mineral nutrient recycling while reducing runoff and water pollution by nitrate. Scientists Meyer et al. recently showed that cover crops also reduce water drainage. Drainage reduction may represent a disservice due to its impact on the groundwater recharge. This is an important issue, particularly in a dry climate with shallow groundwater.

Scientists Allain et al., using a modeling platform, revealed that reducing water use does not necessarily improve downstream river flows nor decrease crop yields. Symmetrically, they showed that a new distribution of reservoirs can highly impact the water consumption and the agricultural economy without changing the water storage capacity. These are new reasons to argue that solving water imbalances is not only a matter of storing versus economizing water!

Plant available water is held in soil pores, which size is affected by soil organic matter content. Organic waste recycling in agriculture can increase soil organic matter contents and improve related soil properties. Agronomists Eden et al. analyzed data from long-term field experiments and found that in almost all cases, plant available water is increased in soils amended with organic wastes.

Domestic wastewaters are used to irrigate soils, thus saving pristine waters. However wastewater contains human enteric viruses that may contaminate the atmosphere after wastewater spraying. Scientists Girardin et al. found that 11-89% of murine mengoviruses applied to the soil were aerosolized during the first half hour. They have developed a model to help policymakers refine standards governing wastewater reuse in irrigation.

Rainfed agriculture refers to farming that relies solely on rainfall for crop growth, versus irrigated agriculture that use extra water. Rainfed agriculture accounts for 60-95% of farmlands in developed countries in Africa, Asia and Latin America. Agronomists Anderson et al. review recent research on rainfed agriculture and suggest that conservation agriculture should improve soil water content and, in turn, crop yields.