Warming autumns at high latitudes of Europe: an opportunity to lose or gain in cereal production?

Regional Environmental Change - Climate change is projected to prolong Finland’s short growing season at both ends though warming autumns are not expected to benefit arable crops such as...     

Effects of soil phosphorus status on environmental risk assessment of glyphosate and glufosinate-ammonium

The increased use of herbicides poses a risk to the aquatic environment. Easy and economical methods are needed to identify the fields where specific environment protection measures are needed. Phosphorus (P) and organophosphorus herbicides compete for the same adsorption sites in soil. In this study the relationship between P obtained in routine Finnish agronomic tests (acid ammonium acetate [P(AC)]) and adsorption of glyphosate and glufosinate-ammonium was investigated to determine whether P(AC) values could be used in the risk assessment. The adsorption of glyphosate ((N-(phosphonomethyl)glycine) and glufosinate-ammonium (2-amino-4-(hydroxymethylphosphinyl)butanoic acid) was studied in a clay and a sandy loam soil enriched with increasing amounts of P added as potassium dihydrogen phosphate. Desorption was also determined for some P-enriched soil samples. The adsorption of both herbicides diminished with increasing P(AC) value. The correlations between Freundlich adsorption coefficients obtained in the adsorption tests and P(AC) were nonlinear but significant (r > 0.98) in both soils. The exponential models of the relationship between soil P(AC) values and glyphosate adsorption were found to fit well to an independent Finnish soil data set (P < 0.1 for glyphosate and P < 0.01 for glufosinate-ammonium). The desorption results showed that glufosinate-ammonium sorption is not inversely related to soil P status, and the high correlation coefficients obtained in the test of the model were thus artifacts caused by an abnormal concentration of exchangeable potassium in soil. The solved equations are a useful tool in assessing the leaching risks of glyphosate, but their use for glufosinate-ammonium is questionable.     

Phosphorus mitigation during springtime runoff by amendments applied to grassed soil

Permanent grass vegetation on sloping soils is an option to protect fields from erosion, but decaying grass may liberate considerable amounts of dissolved reactive P (DRP) in springtime runoff. We studied the effects of freezing and thawing of grassed soil on surface runoff P concentrations by indoor rainfall simulations and tested whether the peak P concentrations could be reduced by amending the soil with P-binding materials containing Ca or Fe. Forty grass-vegetated soil blocks (surface area 0.045 m, depth 0.07 m) were retrieved from two permanent buffer zones on a clay and loam soil in southwest Finland. Four replicates were amended with either: (i) gypsum from phosphoric acid processing (CaSO × 2HO, 6 t ha), (ii) chalk powder (CaCO, 3.3 t ha), (iii) Fe-gypsum (6 t ha) from TiO processing, or (iv) granulated ferric sulfate (Fe[SO], 0.7 t ha), with four replicates serving as untreated controls. Rainfall (3.3 h × 5 mm h) was applied on presaturated samples set at a slope of 5% and the surface runoff was analyzed for DRP, total dissolved P (TDP), total P (TP), and suspended solids. Rainfall simulation was repeated twice after the samples were frozen. Freezing and thawing of the samples increased the surface runoff DRP concentration of the control treatment from 0.19 to 0.46 mg L, up to 2.6-3.7 mg L, with DRP being the main P form in surface runoff. Compared with the controls, surface runoff from soils amended with Fe compounds had 57 to 80% and 47 to 72% lower concentrations of DRP and TP, respectively, but the gypsum and chalk powder did not affect the P concentrations. Thus, amendments containing Fe might be an option to improve DRP retention in, e.g., buffer zones.     

Static yields and quality issues: Is the agri-environment program the primary driver?

The Finnish agri-environmental program (AEP) has been in operation for 20 years with >90 % farmer commitment. This study aimed to establish whether reduced nitrogen (N) and phosphorus (P) use has impacted spring cereal yields and quality based on comprehensive follow-up studies and long-term experiments. We found that the gap between genetic yield potential and attained yield has increased after the AEP was imposed. However, many contemporary changes in agricultural practices, driven by changes in prices and farm subsidies, also including the AEP, were likely reasons, together with reduced N, but not phosphorus use. Such overall changes in crop management coincided with stagnation or decline in yields and adverse changes in quality, but yield-removed N increased and residual N decreased. Further studies are needed to assess whether all the changes are environmentally, economically, and socially sustainable, and acceptable, in the long run. The concept of sustainable intensification is worth considering as a means to develop northern European agricultural systems to combine environmental benefits with productivity.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0637-9) contains supplementary material, which is available to authorized users.     

Lessons from the past in weather variability: sowing to ripening dynamics and yield penalties for northern agriculture from 1970 to 2012

There is evidence for overall spring advancement and phenology shift across the northern hemisphere, including northern Europe, where cereals are grown despite the very short growing season. This study focused on one of the principal risks associated with the short growing season, weather-induced variability in sowing time. The aim was to characterize variation in sowing time, quantify the impacts on crop growth and document associations with weather conditions and variability. We also assessed whether any systematic changes occurred as potential signs of autonomous adaptation to changed conditions. Shifts in spring cereal sowing time had no consistent impact on time of maturity as a result of variable weather conditions. All spring cereal cultivars required fewer days, although more cumulated degree-days, to mature after delays in sowing. In the 1990s and 2000s, sowing tended to start earlier than in the 1970s and 1980s. This was attributable to earlier onset of the growing season. Furthermore, more favorable harvest conditions facilitated harvest after maturity. As more land has been allocated to late-maturing wheat (Triticum aestivum L.) compared with early-maturing barley (Hordeum vulgare L.) during recent decades, autonomous adaptation to climate change has already begun in the northernmost agricultural region of Europe.     

Rainfed crop production challenges under European high-latitude conditions

Regional Environmental Change - Global warming is likely to prolong the growing season at high latitudes where the brevity of the growing season currently limits crop growth and yields. A longer...