Straw mulching allows for effective water storage in dryland wheat production.  Finding a suitable straw mulching model that facilitates wheat growth was the objective of this study.  A 2-year field experiment was conducted to investigate the effects of two straw mulching patterns (FM, full coverage within all the rows; HM, half coverage within alternate rows) and two mulching rates (4.5 and 9.0 t ha^–1) on soil moisture, soil temperature, grain yield, and water use efficiency (WUE) of winter wheat in northern China, with no mulching (M0) as the control.  Results showed that mulching increased the soil water storage in all growth stages under high mulching rates, with a stronger effect in later growth stages.  Water storage under the HM model was greater in later stages than under the FM model.  Soil water content of HM groups was higher than that of FM groups, especially in surface soil layers.  Evapotranspiration decreased in mulched groups and was higher under high mulching rates.  Aboveground biomass during each growth stage under the HM model was higher than that under M0 and FM models with the same mulched rate, leading to a relatively higher grain yield under the HM model.  Mulching increased WUE, a trend that was more obvious under HM9.0 treatment.  Warming effect of soil temperature under the HM pattern persisted longer than under the FM model with the same mulching rates.  Accumulated soil temperature under mulched treatments increased, and the period of negative soil temperature decreased by 9–12 days under FM and by 10–20 days under HM.  Thus, the HM pattern with 9.0 t ha^–1 mulching rate is beneficial for both soil temperature and water content management and can contribute to high yields and high WUE for wheat production in China. 

 

Elevated CO₂ and high N promote the yield of vegetables interactively, whilst their interactive effects on fruit quality of cucumber (Cucumis sativus L.) are unclear.  We studied the effects of three CO₂ concentrations (400 μmol mol–1 (ambient), 625 μmol mol^–1 (moderate) and 1 200 μmol mol^–1 (high)) and nitrate levels (2 mmol L^–1 (low), 7 mmol L^–1 (moderate) and 14 mmol L^–1 (high)) on fruit quality of cucumber in open top chambers.  Compared with ambient CO₂ , high CO₂ increased the concentrations of fructose and glucose in fruits and maintained the titratable acidity, resulting in the greater ratio of sugar to acid in moderate N, whilst it had no significant effects on these parameters in high N.  Moderate and high CO₂ had no significant effect on starch concentration and decreased dietary fiber concentration by 13 and 18%, nitrate by 31 and 84% and crude protein by 19 and 20% averagely, without interactions with N levels.  The decreases in amino acids under high CO₂ were similar, ranging from 10–18%, except for tyrosine (50%).  High CO₂ also increased the concentrations of P, K, Ca and Mg but decreased the concentrations of Fe and Zn in low N, whilst high CO₂ maintained the concentrations of P, K, Ca, Mg, Fe, Mn, Cu and Zn in moderate and high N.  In conclusion, high CO₂ and moderate N availability can be the best combination for improving the fruit quality of cucumber.  The fruit enlargement, carbon transformation and N assimilation are probably the main processes affecting fruit quality under CO₂ enrichment.