Irrigation quotas for high water use efficiency and economic water productivity of typical crops in Shiyang River Basin北大核心CSCD

Water consumption in agricultural activities is the main water use in inland oases in Northwest China. Research on water conservation in agriculture is of great significance to alleviate the conflict between the use of agricultural and ecological water and is of great importance to local farmers’ livelihoods. This study, based on traditional irrigation practices (flood irrigation and fixed irrigation frequency) of Minqin County in Shiyang River Basion, was designed to reveal the impacts of five irrigation quotas (1 800, 1 440, 1 080, 720, and 360 m3/hm2) on crop yield, biomass, irrigation water use efficiency (IWUE), and economic water productivity (EWP) to determine the optimal irrigation for five crops and guide local irrigation practices. The results showed that: (1) Under the five irrigation quotas, IWUE of corn, with the highest of 12.27 kg/m3, was higher than the other four crops; (2) The average EWP of cotton with a 2-year-average of 8.0 yuan/m3 was higher than the other four crops. Thus, the economic output of cotton is the best under the same irrigation quota; (3) Considering the yield, IWUE, EWP, and biomass, corn was better than the other four typical crops; and (4) 1 080 m3/hm2 was the optimal irrigation quota for sunflower in local planting practices. In addition, 720 m3/hm2 was suitable for corn, pepper, wheat, and cotton as their irrigation quota. This study shows that reducing the amount of irrigation quota in the Shiyang River Basin can effectively improve local IWUE and EWP. © 2022 Authors. All rights reserved.     

Economic effects of CO2 fertilization of crops: transforming changes in yield into changes in supply

Increasing concentrations of atmospheric carbon dioxide CO₂ have a beneficial effect on crop production that would tend to offset some of the economic losses that might be generated in some areas by the climatic effects of atmospheric CO₂ and other greenhouse gases. Previous estimates of the economic benefits of CO₂ fertilization on world crop production, however, were based on the assumption that percent changes in supply are equal to percent changes in yield. This assumption is not valid, however, because it confounds changes in supply with changes in quantity supplied. This error leads to an overestimation of the real economic benefits of CO₂ fertilization by 61–166%. The effects of CO₂ fertilization on crop production, therefore, will reduce some of the potential damages caused by the climatic impacts of greenhouse gases, but by significantly less than that indicated in earlier research.     

试论开展中国农作物病虫害危害流行的长期气象预测研究

从开展中国宵作物病虫害危害浒的长期气象预测研究的必要性出发,结合国内外的研究现状,提出提高宵作物病虫害长期预测的准确性、时效性是宵作物病虫病综合防治的首要措施,并建议围绕中国宵作物病虫害宏观气候可预测性的机理、浒的前兆性气候指标、浒气候区划、影响的关键气象因子、预报模式的气象信息技术改造等方面开展中国宵作物病虫害危害流行的长期气象预测研究。