Effects of nitrogen fertilization on the acidity and salinity of greenhouse soils

Abstract

A greenhouse pot experiment was conducted to study the effects of conventional nitrogen fertilization on soil acidity and salinity. Three N rates (urea; N0, 0 kg N ha(-1); N1, 600 kg N ha(-1); and N2, 1,200 kg N ha(-1)) were applied in five soils with different greenhouse cultivation years to evaluate soil acidification and salinization rate induced by nitrogen fertilizer in lettuce production. Both soil acidity and salinity increased significantly as N input increased after one season, with pH decrease ranging from 0.45 to 1.06 units and electrolytic conductivity increase from 0.24 to 0.68 mS cm(-1). An estimated 0.92 mol H(+) was produced for 1 mol (NO2 (-) + NO3 (-))-N accumulation in soil. The proton loading from nitrification was 14.3-27.3 and 12.1-58.2 kmol H(+) ha(-1) in the center of Shandong Province under N1 and N2 rate, respectively. However, the proton loading from the uptake of excess bases by lettuces was only 0.3-4.5 % of that from nitrification. Moreover, the release of protons induced the direct release of base cations and accelerated soil salinization. The increase of soil acidity and salinity was attributed to the nitrification of excess N fertilizer. Compared to the proton loading by lettuce, nitrification contributed more to soil acidification in greenhouse soils.

Accelerated phosphorus accumulation and acidification of soils under plastic greenhouse condition in four representative organic vegetable cultivation sites

“…Soil pH, organic matter (OM) and 10 the various P accumulation characteristics were investigated. We found that soil pH in PGVS were 11 significantly decreased by 0.57~1.17 unit with obvious signs of acidification, compared with that in 12 OVS. Soil OM was different for different sampling locations, but in general it was higher in PGVS 13 than OVS.…”

“…By 11 comparison, the amount of T-P i in PGVS was significantly higher than that of OVS in S2, S3 and 12 S4 (Table 3).…”

Effects of Continuous Tomato Monoculture on Soil Microbial Properties and Enzyme Activities in a Solar Greenhouse

“…They are therefore suitable for crop production in the cold regions of northern China [1,2], and provide much higher yields and incomes than open field cultivation [3,4]. However, microclimate factors in greenhouses, such as the temperature, lightintensity, humidity, and aeration, and management methods, including tillage and fertilization, can give rise to soil acidification, secondary salinization, and nutrient enrichment and unbalance [5][6][7][8].…”

Identification of discrepancies in grain quality and grain protein composition through avenin proteins of oat after an effort to increase protein content

“…Evidence from the previous experiments showed that fertilization with high amounts of N 2 increased globulin relative to other fractions of oat protein [28]. Consequently, an increase in protein content here may be due to the capacity for maximum absorption of nitrogen in the container-grown plants in the greenhouse due to less percolation compared with soil in the field, which allows maximum permeation or percolation [29]. This could probably increase the globulin fractions that eventually gave a high protein percentage.…”