From dimming to brightening during 1961 to 2014 in the maize growing season of China

Effects of different fertilization practices on maize yield, soil nutrients, soil moisture, and water use efficiency in northern China based on a meta-analysis

The application of fertilizer to ensure the steady improvement of crop yield has become the main means of agricultural production. However, it remains to be determined whether fertilization practices with different combinations of nitrogen (N), phosphorus (P), potassium (K), and organic (O) fertilizers play a positive role in the sustainability of maize yield and the soil in which it is grown. Therefore,this meta-analysis extracted 2663 data points from 76 studies to systematically analyze and explore the effects of different fertilization measures on maize yield, soil nutrients, water content and water use efficiency (WUE) in northern China. Articles addressing this topic showed that fertilization effectively increased the soil nutrient content and maize yield. The soil organic matter (SOM) increased by 2.36 (N)-55.38% (NPO), total nitrogen content increased by 6.10 (N)-56.39% (NPO), available phosphorus content increased by 17.12 (N)-474.74% (NPO), and available potassium content changed by - 2.90 (NP)-64.40% (NPO). Soil moisture increased by 3.59% under a single organic fertilizer application and decreased by 4.27-13.40% under the other treatments. Compared with no fertilization, the yield increase of fertilized maize reached 11.65-220.42%. NP, NPK and NPKO contributed the most to increased yield in lithological, black and fluvo-aquic soils, respectively. The effects of different fertilization practices on maize yield varied in response to the same meteorological factors. The WUE increased from 9.51 to 160.72%. In conclusion, rational fertilization can improve the soil nutrient content and increase maize yield. The combined application of chemical and organic fertilizer showed the greatest increase in yield and WUE. Organic fertilizer application alone increased soil moisture. Our results provide a theoretical basis for fertilizer application and for improving the soil structure for maize cultivation in northern China.

Assessing impacts of global climate change on water and food security in the black soil region of Northeast China using an improved SWAT-CO2 model

Future climate change may have substantial impacts on both water resources and food security in China's black soil region. The Liao River Basin (LRB; 220,000 km²) is representative of the main black soil area, making it ideal for studying climate change effects on black soil. In this study, the Soil and Water Assessment Tool (SWAT) model was first initialized for the LRB. Actual evapotranspiration (ET_a) values calculated using the Surface Energy Balance System (SEBS) model and city-level corn (Zea mays L.) yields were then used to calibrate the SWAT model. Finally, the SWAT model was modified to accept dynamic CO₂ input and output crop transpiration, soil evaporation, and canopy interception separately to explore the impacts of future climate change on ET related variables and crop water productivity (CWP) in the LRB. Simulation scenario design included 22 General Circulation Models (GCMs) and 4 Shared Socioeconomic Pathways (SSPs) scenarios from the latest Coupled Model Intercomparison Project 6 (CMIP6) for two 30-year periods of 2041-2070 and 2071-2100. The predicted results showed a significant (P < 0.05) increase in air temperatures and precipitation in the LRB. In contrast, solar radiation decreased significantly and was most reduced for the SSP3-7.0 scenario. Reference evapotranspiration (ET_o), ET_a, and soil evaporation significantly increased in future scenarios, while canopy interception and crop transpiration showed significant reductions, particularly under the 2071-2100 SSP5-8.5 scenario. Overall, corn yield elevated considerably (P < 0.05) with the largest increase for the SSP5-8.5 scenario during 2071-2100. However, the SSP3-7.0 scenario indicated a significant decline in yield. Future changes in CWP were similar to those for corn yield, with significant increases in the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. These findings suggested future climate change may have a positive impact on corn production in the black soil region of the LRB.

Quantitative Relationship Between Solar Radiation and Grain Filling Parameters of Maize

A quantitative understanding of the factors driving changes in grain filling is essential for effective prioritization of increasing maize yield. Grain filling is a significant stage in maize yield formation. Solar radiation is the energy source for grain filling, which is the ultimate driving factor for final grain weight and grain filling capacity that determine maize yield. Here, we first confirmed the quantitative relationships between grain filling parameters and photosynthetically active radiation (PAR) by conducting field experiments using different shading and plant density conditions and cultivars in 2019 and 2020 in Xinjiang, China. The results showed that with every 100 MJ m-2 increase in PAR, the average grain filling rate (G ave), maximum grain-filling rate (G max), and the kernel weight at the time of maximum grain-filling rate (W max) increased by 0.073 mg kernel-1 day-1, 0.23 mg kernel-1 day-1, and 0.24 mg kernel-1, and the time of maximum grain-filling rate (T max) delayed by 0.91 day. Relative changes in PAR were significantly and positively correlated with relative changes in yield and G ave. With every 1% change in PAR, yield and G ave changed by 1.16 and 0.17%, respectively. From the perspective of grain filling capacity, DH618 was a more shade-resistant cultivar than XY335 and ZD958. It is urgent to breed maize cultivars with low light tolerance and high grain yield in the face of climate change, particularly the decrease in solar radiation.

Assessing influences of climate change on highland barley productivity in the Qinghai-Tibet Plateau during 1978-2017

Grain production is becoming increasingly vulnerable to climate change globally. Highland barley (HB) is the most important cereal crop in the Qinghai-Tibet Plateau (QTP), so assessing HB productivity and its response to climate change could help to understand the capacity of grain production and food security. This study simulated the potential yield of HB annually at 72 meteorological stations for 1978–2017 using the WOFOST model, and then analyzed the spatiotemporal changes of HB potential yield and climatic factors in the growing season. Further, the influence of climate change on HB potential yield was explored in different temperature zones (TZ). Results indicate that the annual average of HB potential yield ranged from 3.5 to 8.1 t/ha in the QTP, and it was averaged at 6.5 t/ha in TZ-3, higher than other zones. From 1978 to 2017, HB potential yield for the whole QTP decreased slightly by 2.1 kg/ha per year, and its change rates were 23.9, 10.1, − 15.9, − 23.8 and − 16.7 kg/ha/year from TZ-1 to TZ-5 (p < 0.05), respectively. In all zones, average (Tave), maximum (Tmax) and minimum temperature (Tmin) showed a significantly warming trend (p < 0.01), and Tmin increased by 0.53, 0.45, 0.44, 0.40 and 0.69 °C per decade, higher than that of Tave and Tmax. However, temperature diurnal range (TDR) and radiation (RA) showed a downward trend, and their decrease rates were far higher in TZ-5 and TZ-3. In TZ-1, ΔTDR was the critical factor to the change in HB potential yield, which would increase by 420.30 kg/ha for 1 °C increase of ΔTDR (p < 0.01). From TZ-2 to TZ-5, ΔRA was the critical factor, but the influence amplitude in terms of the elastic coefficient, decreased from 4.08 to 0.99 (p < 0.01). In addition, other factors such as ΔTmax in TZ-3 and ΔTmin in TZ-4 and TZ-5 also had an important influence on the potential yield. To improve the HB productivity in the QTP, suitable varieties should be developed and introduced to adapt the climate warming in different temperature zones. In addition, efforts are needed to adjust the strategies of fertilizers and irrigation applications.