The study showed that the open water of the Bothnian Sea (BS) is likely to have shifted from altering nitrogen and phosphorous limitations of the spring bloom to more nitrogen-limited conditions ...during the last 20 years. This is affected by the by inflow of phosphate-rich and oxygen-depleted water from depths near the halocline in the northern Baltic Proper, where severe oxygen conditions currently cause extreme phosphate concentrations in the deep water. The change in relation between inorganic nitrogen and phosphorous in the BS occurs first in the deep water and then progresses to the surface water. The change can potentially cause increased production in the BS and more frequent cyanobacterial blooms. There does not appear to be any immediate concern in the short-term perspective for the state of the BS, but a progression of the processes may lead to a more eutrophic state of the BS.
To reduce eutrophication of the Baltic Sea, all nine surrounding countries have agreed upon reduction targets in the HELCOM Baltic Sea Action Plan (BSAP). Yet, monitoring sites and model concepts for ...decision support are few. To provide one more tool for analysis of water and nutrient fluxes in the Baltic Sea basin, the HYPE model has been applied to the region (called Balt-HYPE). It was used here for experimenting with land-based remedial measures and future climate projections to quantify the impacts of these on water and nutrient loads to the sea. The results suggest that there is a possibility to reach the BSAP nutrient reduction targets by 2100, and that climate change may both aggravate and help in some aspects. Uncertainties in the model results are large, mainly due to the spread of the climate model projections, but also due to the hydrological model.
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.
Celem pracy była ocena zmian aktywności fosfatazy alkalicznej i fosfatazy kwaśnej oraz zawartości węgla organicznego (Corg) i fosforu przyswajalnego dla roślin (PE-R) w glebie rok po pożarze ...wywołanym niekontrolowanym wypalaniem traw. Stwierdzono niewielki wzrost (14%) węgla organicznego w glebie rok po pożarze, w porównaniu z kontrolą, a także 84% wzrost zawartości przyswajalnego fosforu. Na podstawie wyników aktywności fosfomonoesteraz obliczono współczynnik inhibicji (IN) dla tych enzymów. Stwierdzono dużą inaktywację fosfatazy alkalicznej (–54,4%) i fosfatazy kwaśnej (–41,5%) w glebie rok po pożarze. Uzyskano istotnie dodatnią wartość współczynnika korelacji między zawartością węgla organicznego i przyswajalnego fosforu (r = 0,403, p < 0,05) oraz istotnie dodatnią zależność między aktywnością fosfatazy alkalicznej zawartością węgla organicznego (r = 0,691, p < 0,05) oraz ujemną korelację między aktywnością kwaśnej fosfatazy i przyswajalnego fosforu (r = –0,877, p < 0,05).
Biyolojik arıtma çamurları organik madde, azot ve fosfor içeriği yönünden zengin bir kaynaktır. Bu nedenle tarımda kullanımı oldukça önemlidir. Magnezyum amonyum fosfat (MAP) çöktürmesi sonucu elde ...edilen strüvit, endüstriyel hammadde ve tarımsal gübre olarak kullanım için uygundur. Arıtma çamurlarından azot ve fosfor geri kazanımı için kullanılan yöntemlerin başında asidik şartlarda azot ve fosforun sıvı faza geçirilmesi gelmekte ve akabinde MAP çökelmesi ile strüvit elde edilmesi sağlanmaktadır. Bu yöntem için en büyük sorun asidifikasyon işlemi ile sıvı faza geçen ağır metallarin strüvite bağlanmasıdır. Çalışmamızda yeni bir çamur dezentegrasyon yöntemi darbeli elektrik alan (PEF) tekniği ile evsel nitelikteki biyolojik atık çamurdan azot ve fosfor geri kazanımı gerçekleştirilmiştir. Çalışma iki aşamadan oluşmaktadır. Birinci aşama; biyolojik atık çamurdaki azot ve fosforun kimyasal eklemeden PEF tekniği ile geri kazanımı. İkinci aşama ise PEF ön arıtımı sonrası sıvı fazda elde edilen yüksek azot ve fosfordan MAP çöktürmesi ile strüvit elde edilmesi şeklindedir. MAP çökeltim testlerinde optimum sıcaklık, pH ve çökelme süresi sırasıyla 20 °C, 9.5 ve 24 saat olarak belirlenmiştir. En iyi çökelme ve giderim verimi 2.5 ml MgCl2.6H2O (0.015 M) ve 2.5 ml H3PO4 (0.049M) eklenmiş örnekte elde edildi. Çökeltim sonrası TN ve TP giderim verimleri sırasıyla %52 ve %14’tür. Çökeltim sonrası kristal yapılı çökelti oluşumu gözlenmiş ve XRD analizi sonucunda bu çökeltinin strüvit olduğu tespit edilmiştir.
Biyolojik arıtma çamurları organik madde, azot ve fosfor içeriği yönünden zengin bir kaynaktır. Bu nedenle tarımda kullanımı oldukça önemlidir. Magnezyum amonyum fosfat (MAP) çöktürmesi sonucu elde ...edilen strüvit, endüstriyel hammadde ve tarımsal gübre olarak kullanım için uygundur. Arıtma çamurlarından azot ve fosfor geri kazanımı için kullanılan yöntemlerin başında asidik şartlarda azot ve fosforun sıvı faza geçirilmesi gelmekte ve akabinde MAP çökelmesi ile strüvit elde edilmesi sağlanmaktadır. Bu yöntem için en büyük sorun asidifikasyon işlemi ile sıvı faza geçen ağır metallarin strüvite bağlanmasıdır. Çalışmamızda yeni bir çamur dezentegrasyon yöntemi darbeli elektrik alan (PEF) tekniği ile evsel nitelikteki biyolojik atık çamurdan azot ve fosfor geri kazanımı gerçekleştirilmiştir. Çalışma iki aşamadan oluşmaktadır. Birinci aşama; biyolojik atık çamurdaki azot ve fosforun kimyasal eklemeden PEF tekniği ile geri kazanımı. İkinci aşama ise PEF ön arıtımı sonrası sıvı fazda elde edilen yüksek azot ve fosfordan MAP çöktürmesi ile strüvit elde edilmesi şeklindedir. MAP çökeltim testlerinde optimum sıcaklık, pH ve çökelme süresi sırasıyla 20 °C, 9.5 ve 24 saat olarak belirlenmiştir. En iyi çökelme ve giderim verimi 2.5 ml MgCl2.6H2O (0.015 M) ve 2.5 ml H3PO4 (0.049M) eklenmiş örnekte elde edildi. Çökeltim sonrası TN ve TP giderim verimleri sırasıyla %52 ve %14’tür. Çökeltim sonrası kristal yapılı çökelti oluşumu gözlenmiş ve XRD analizi sonucunda bu çökeltinin strüvit olduğu tespit edilmiştir.
The large majority of biofuels to date is “first-generation” biofuel made from agricultural commodities. All first-generation biofuel production systems require phosphorus (P) fertilization. P is an ...essential plant nutrient, yet global reserves are finite. We argue that committing scarce P to biofuel production involves a trade-off between climate change mitigation and future food production. We examine biofuel production from seven types of feedstock, and find that biofuels at present consume around 2% of the global inorganic P fertilizer production. For all examined biofuels, with the possible exception of sugarcane, the contribution to P depletion exceeds the contribution to mitigating climate change. The relative benefits of biofuels can be increased through enhanced recycling of P, but high increases in P efficiency are required to balance climate change mitigation and P depletion impacts. We conclude that, with the current production systems, the production of first-generation biofuels compromises food production in the future.
The large variation in the relationships between environmental factors and plant traits observed in natural communities exemplifies the alternative solutions that plants have developed in response to ...the same environmental limitations. Qualitative attributes, such as growth form, woodiness, and leaf habit can be used to approximate these alternative solutions. Here, we quantified the extent to which these attributes affect leaf trait values at a given resource supply level, using measured plant traits from 105 different species (254 observations) distributed across 50 sites in mesic to wet plant communities in The Netherlands. For each site, soil total N, soil total P, and water supply estimates were obtained by field measurements and modeling. Effects of growth forms, woodiness, and leaf habit on relations between leaf traits (SLA, specific leaf area; LNC, leaf nitrogen concentration; and LPC, leaf phosphorus concentration) vs. nutrient and water supply were quantified using maximum-likelihood methods and Bonferroni post hoc tests. The qualitative attributes explained 8-23% of the variance within sites in leaf traits vs. soil fertility relationships, and therefore they can potentially be used to make better predictions of global patterns of leaf traits in relation to nutrient supply. However, at a given soil fertility, the strength of the effect of each qualitative attribute was not the same for all leaf traits. These differences may imply a differential regulation of the leaf economy traits at a given nutrient supply, in which SLA and LPC seem to be regulated in accordance to changes in plant size and architecture while LNC seems to be primarily regulated at the leaf level by factors related to leaf longevity.
Cekaman rendaman merupakan salah satu masalah utama yang dihadapi dalam kegiatan budidaya padi di lahan rawa lebak. Tujuan penelitian ini adalah untuk mengetahui pengaruh pemberian fosfor sebelum ...tanaman terendam yang diharapkan mampu meningkatkan ketahanan tanaman padi terhadap cekaman rendaman. Penelitian disusun menggunakan Rancangan Petak Terbagi (Split Plot) dengan varietas padi sebagai petak utama dan waktu pemberian fosfor sebagai anak petak yang masing-masing diulang sebanyak 3 kali. Varietas padi yang digunakan yaitu IR 42, Inpari 30, dan Ciherang. Waktu pemberian fosfor terdiri dari kontrol (P0), pemberian fosfor 3 hari sebelum perendaman (P1), 7 hari sebelum perendaman (P2), dan 14 hari sebelum perendaman (P3). Hasil penelitian menunjukkan bahwa Ciherang merupakan varietas yang paling terhambat pertumbuhannya akibat cekaman rendaman. Selain itu, perlakuan P2 (aplikasi fosfor pada 7 hari sebelum perendaman) menunjukkan hasil terbaik dibandingkan perlakuan lain yang secara signifikan ditunjukkan pada peubah luas daun, berat kering akar dan total berat kering tanaman pada 6 minggu setelah tanam atau 14 hari setelah perendaman. Data yang dihasilkan diharapkan mampu menjadi bahan pertimbangan dalam perbaikan teknis budidaya padi di lahan rawa lebak. One of the major constraints of rice cultivation in the non-tidal swamp area is submergence stress, which is considered could be managed by phosphorus application before submergence in order to increase rice tolerance towards submergence stress condition. Split plot design was used in this research with three replicates. Rice cultivars served as the main plot consisted of IR42, Inpari 30, and Ciherang. While for the sub-plot was phosphorus application consisted of P0 = control, P1 = phosphorus application 3 days before submergence, P2 = phosphorus application 7 days before submergence, and P3 = phosphorus application 14 days before submergence. Results showed that Ciherang was the most affected cultivar due to submergence stress. Furthermore, P2had better performance compared to other P treatments as significantly showed in leaf area, dry root weight, and total dry weight at 6 weeks after sowing or 14 days after submergence. The resulted data hopefully can be used as a consideration for swamp rice cultivation improvement effort.
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