The effects of the substitution of polyacrylamide for activated carbon in the sodium bicarbonate extraction of soils for available inorganic phosphorus

Non-Peer Reviewe

Rural sustainable drainage systems:a practical design and build guide for Scotland's farmers and landowners

Soil cultivation, manure / fertiliser applications and chemical spraying can all contribute to diffuse pollution from agricultural land. Rainfall runoff from farm roads, tracks, yards and dusty roofs are also potential sources of diffuse pollution. Whilst many changes in farming practice have dealt with these sources of pollution there still remains instances where small amounts escape from a farmyard into a nearby ditch or where sediment laden overland field flows make their way into a ditch or burn, river or natural wetland and finally the sea. This not only has cost implications for a farmer but these incidents across a catchment have a huge impact on our water environment. Rural Sustainable Drainage Systems (Rural SuDS) will reduce agricultural diffuse pollution impacts as they are physical barriers that treat rainfall runoff. They are low cost, above ground drainage structures that capture soil particles, organic matter, nutrients and pesticides before they enter our water environment. Rural SuDS for steadings prevent blockages in drains and ditches. They contribute to good environmental practice and farm assurance schemes. In fields they can be used for returning fertile soil back to farmland and will help your business become more resilient to the impacts of climate change. Trapping soils, organic matter and nutrients means that valuable assets can be reclaimed – recent studies indicate savings of £88 per hectare per year! This Design and Build guide can be used by farmers and land managers to reduce diffuse pollution

Broadcast and residual P versus annual seed-placed P

Non-Peer ReviewedThe yield and nutrient uptake effects of single broadcast P treatments, annual seed-placed P treatments and their combination, were studied over five years. Maximum yield was attained from a combination of moderate levels of seed-placed and broadcast P applications. Moderate broadcast treatments (40 kg P/ha) alone produced a five-year average yield which closely approached the yield from large annual seed-placed treatments ( 20 kg P/ha/year), while larger residual treatments exceeded it. The Zn concentration in plants on plots receiving 160 kg P/ha was significantly reduced and approached levels considered deficient. After the production of five wheat crops on plots which received the broadcast application of 160 kg P/ha, the distribution of the remaining fertilizer residues among various soil P fractions was: resin-P, 35 %; NaOH-P, 30-40 %; NaHCO3-P, 15 %; HCl-P, 0-5 %; H2SO4-P, 5 %; aggregate-protected P, 5 %. Half the fertilizer residues remained in plant available forms (resin-P, NaHCO3-P)

Recent work on copper and molybdenum in pastures and soils in Saskatchewan

Non-Peer Reviewe

Residual phosphate studies

Non-Peer ReviewedData on yield and P uptake by flax and wheat is presented from the first year of an eight year residual phosphate (P) study located on the Kernen Farm of the University of Saskatchewan. Comparison of seed-placed (0, 5, 10, 20, and 40 kg P ha-1) and broadcast P (0, 40, 80, 160, and 320 kg P ha-1) treatments showed that there was a yield response to both types of P fertilizer application with maximum yields being obtained in wheat by either 40 kg P ha-1 seed-placed or by broadcast P application of 80 to 160 kg P ha-1, and in flax by 5-10 kg P ha-1 side-banded or 80 kg P ha-1 broadcast. Laboratory studies related the prediction of fertilizer P response from seed-placed treatments to broadcast treatments by use of P sorption and P extraction techniques. P sorption isotherms were run on over 300 soil samples taken from the 0-15 cm layer of cultivated fields representing the majority of the cultivated soil associations in Saskatchewan. This data would suggest that rates of P broadcast should be four to eight times higher than recommended seed-placed or side-banded rates in the same Soil Zone with the same available P content

Management effects on phosphorus transformation and implications for soil test recommendations

Non-Peer ReviewedCrop rotations and fertilizer application on long-term rotation plots at Lethbridge and Breton have dramatically affected most soil phosphorus (P) fractions. At the Lethbridge site, soil cultivation has reduced organic P (Po) levels as a result of mineralization. This has caused a significant increase in resin extractable inorganic P (Pi; most biologically available), sodium bicarbonate extractable Pi (sorbed to soil surfaces), and sodium hydroxide extractable Pi (more strongly bound to Al and Fe compounds) levels. In non-fertilized treatments, continuous wheat (CW) resulted in greater P draw-down of all labile P fractions than in wheat-wheat-fallow (WWF) and wheat-fallow (WF) rotations. The addition of P fertilizer has significantly increased Resin-Pi, Bicarb-Pi and NaOH-Pi fractions. The addition of N fertilizer has resulted in increased Bicarb-Po and NaOH-Po levels in the CW, WF, and WWF rotations. At the Breton site, continuously cropped treatments, which had not received fertilizer, resulted in greater P draw-down of all P fractions except Residual-F. Addition of fertilizer had a significant effect on all P fractions (except NaOH-Po). The added Pin the fertilizer treatments positively affected the Pi fractions and the N in the fertilizer treatment positively affected the Po fractions. Bicarb-Po levels were found to be negatively· affected by soil pH. Finally, cropping without using phosphate fertilizer has resulted in a 30 to 41 % decline in Total-P in the Breton plots. A growth chamber study was conducted to compare four routine soil test P methods with plant uptake of P. Wheat and canola were each grown in eight soils from the Lethbridge and Breton plots with different pedogenic, crop rotation and fertilizer histories. Results of the study confirm that one calibration curve to predict fertilizer P requirements for a wide range of soils and crops is virtually impossible. Future soil tests will combine a chemical extractant with a computer model prediction of Po mineralization. Much more information is needed on root rhizosphere dynamics

Critical evaluation of methods for determining total organic phosphorus in tropical soils

The determination of total organic phosphorus (TOP) in soils presents several methodological problems, particularly on strongly weathered and tropical soils. We reviewed the application of several methods for TOP determination to soils from different zones of the globe and evaluated the applicability of one ignition and two extraction methods to tropical soils from Brazil and Ghana. Reproducibility (coefficients of variation) was within 6% for the ignition method, and 13% for the extraction methods, due to the simplicity of the former. The two extraction methods produced results similar to each other, while the ignition method generally gave higher TOP contents. Unusually low C to organic P ratios indicate that the ignition method overestimated TOP in several soils. The Bowman extraction method, developed on weakly weathered soils, appeared also suitable for a variety of tropical soils

14 Principles for better Practice: Principles for Land Practitioners based on Indigenous and Gaelic Heritage

These 14 principles are distilled from a conversation among three creative practitioners whose work revolves around ideas of land, people, and heritage; as well as inclusions from others who have spoken and written thoughtfully on the topics of indigeneity, ancestry, and kinship. For one of us, this is a specifically Gaelic practice, drenched in their own history, their architectural work focuses on nurturing a return of resources and abundance to the Western Isles. For another, their identity and their collaborative creative work are one, rooted in indigenous and colonial ancestry reaching through creative technologies to work across the global north and south. For the third, the work is an evolving academic discourse about the power of community in action, and the notion that our regenerative futures depend on an integration of old ways of knowing with the now, innovation from tradition. These principles are a guide to keep ever present as we all continue to do work within the ecosystem of people, processes, and place. Whether you are a facilitator, an educator, a developer, a builder, a maker, we can all do with a reminder to think of the big picture, past and present as we shape the future

Specific Cooperation Between Imp-α2 and Imp-β/Ketel in Spindle Assembly During Drosophila Early Nuclear Divisions

The multifunctional factors Imp-α and Imp-β are involved in nuclear protein import, mitotic spindle dynamics, and nuclear membrane formation. Furthermore, each of the three members of the Imp-α family exerts distinct tasks during development. In Drosophila melanogaster, the imp-α2 gene is critical during oogenesis for ring canal assembly; specific mutations, which allow oogenesis to proceed normally, were found to block early embryonic mitosis. Here, we show that imp-α2 and imp-β genetically interact during early embryonic development, and we characterize the pattern of defects affecting mitosis in embryos laid by heterozygous imp-α2D14 and imp-βKetRE34 females. Embryonic development is arrested in these embryos but is unaffected in combinations between imp-βKetRE34 and null mutations in imp-α1 or imp-α3. Furthermore, the imp-α2D14/imp-βKetRE34 interaction could only be rescued by an imp-α2 transgene, albeit not imp-α1 or imp-α3, showing the exclusive imp-α2 function with imp-β. Use of transgenes carrying modifications in the major Imp-α2 domains showed the critical requirement of the nuclear localization signal binding (NLSB) site in this process. In the mutant embryos, we found metaphase-arrested mitoses made of enlarged spindles, suggesting an unrestrained activity of factors promoting spindle assembly. In accordance with this, we found that Imp-βKetRE34 and Imp-βKetD bind a high level of RanGTP/GDP, and a deletion decreasing RanGTP level suppresses the imp-βKetRE34 phenotype. These data suggest that a fine balance among Imp-α2, Imp-β, RanGTP, and the NLS cargos is critical for mitotic progression during early embryonic development