Blending controlled-release urea and urea under ridge-furrow with plastic film mulching improves yield while mitigating carbon footprint in rainfed potato.

Ridge-furrow with plastic film mulching and various urea types have been applied in rainfed agriculture, but their interactive effects on potato (Solanum tuberosum L.) yield and especially environments remain poorly understood. A three-year experiment was conducted to explore the responses of tuber yield, methane (CH4) and nitrous oxide (N2O) emissions, net global warming potential (NGWP), carbon footprint (CF), and net ecosystem economic budget (NEEB) of rainfed potato to two mulching practices [plastic film mulching (RM) and no plastic film mulching (NM)] and three urea types [conventional urea (U), controlled-release urea (C), and a mixture of equal amounts of conventional urea and controlled-release urea at a ratio of 1:1 (CU)] and their interactions. The results showed that RM significantly decreased cumulative N2O emissions and CH4 uptake by 4.9% and 28.4%, but significantly increased NGWP by 8.9% relative to NM. Compared with U, the C and CU produced much lower cumulative N2O emissions and NGWP and higher CH4 uptake. The interaction of mulching methods and urea type had significant influence on tuber yield and NEEB. Considering both environment and production, RMCU could not only achieve a high tuber yield and NEEB (by up to 26.5% and 42.9%, respectively), but also reduce the CF (by up to 13.7%), and therefore should be considered an effective strategy for dryland potato.

Effect of synthetic and natural water-absorbing soil amendments on photosynthesis characteristics and tuber nutritional quality of potato in a semi-arid region.

BACKGROUND: The effect of water-absorbing soil amendments on photosynthesis characteristics and tuber nutritional quality was investigated in a field experiment in a semi-arid region in northern China in 2010-2012. Treatments included two synthetic water-absorbing amendments, potassium polyacrylate (PAA) and polyacrylamide (PAM), and one natural amendment, humic acid (HA), both as single amendments and compound amendments (HA combined with PAA or PAM), and a no amendment control. RESULTS: Soil amendments had a highly significant effect (P ≤ 0.01) on photosynthesis characteristics, dry biomass, crop root/shoot (R/S) ratio and tuber nutritional quality. They improved both dry biomass above ground and dry biomass underground in the whole growing season by 4.6-31.2 and 1.1-83.1% respectively in all three years. Crop R/S ratio was reduced in the early growing season by 2.0-29.4% and increased in the later growing season by 2.3-32.6%. Soil amendments improved leaf soil plant analysis development value, net photosynthesis rate, stomatal conductance and transpiration rate by 1.4-17.0, 5.1-45.9, 2.4-90.6 and 2.0-22.6% respectively and reduced intercellular CO2 concentration by 2.1-19.5% in all three years. CONCLUSION: Amendment treatment with PAM + HA always had the greatest effect on photosynthesis characteristics and tuber nutritional quality among all amendment treatments and thus merits further research.