and subsampling. Furthermore, you are not as logistically constrained as when you must return to the field for repeated sampling. Sounds ideal! However, you should not underestimate the challenges.
Let us take an example. You want to investigate CO2 emissions from a range of soil types treated with a commercial amendment. Each incubation chamber requires 150 g dry weight of soil and you want to apply three rates of amendment plus an untreated control. You plan on using four replicates and four different soil types. This means you need 64 chambers, each with 150 g dry soil, or 9.6 kg. That doesn't seem like a lot but consider that you are not sampling dry soil in the field. You will collect the substrate by digging blocks of soil from 0–15 cm, removing the root mat, and aggregating. Samples will be air dried, sieved to 2 mm, and finally packed to a specified bulk density in the chambers. First, consider that field soil is not equivalent to dry soil as it contains both solid mineral particles and pore water (typically up to 25% or 30%, depending on soil type and recent weather). Therefore, much of the sample you collect in the field will actually be water, which is of no use to you. Second, you do not need the large particles, roots, rocks, and pebbles, which will be sieved out. The proportion of your sample which will be made up of this surplus depends entirely on your soil types, but suffice to say, you will need to collect far more soil than the <10 kg dry weight equivalent that will actually fill your chambers. You will need a suitable vehicle for accessing the fields, sampling tools and containers, manpower, time, and all safety equipment, PPE, and other gear which you need when going to the field. Of course, this is just one example. You might be collecting vegetation samples for cultivation in a glasshouse, trapping wild animals for tagging and release; it all depends on your unique research. However, the same basic principles of fieldwork should be adhered to throughout sampling, even though the actual experiment will be conducted back at the laboratory. In summary, you should be equally prepared for the logistical challenges even if you are not running field trials or setting up observatories.
References
1 Cassler, M.D. (2014). Fundamentals of experimental design: Guidelines for designing successful experiments. Agronomy Journal 107(2), 692–705.
2 Facchi, A., Gandolfini, C. and Whelan, M.J. (2007). A comparison of river water quality sampling methodologies under highly variable load conditions. Chemosphere 66(4), 746–56.
3 Glaz, B. and Yeater, M. (eds). (2017). Applied Statistics In Agricultural, Biological, and Environmental Sciences. Madison, WI: ASA, CSSA, and SSSA.
4 Howden, N.J.K., Burt, T.P., Worrall, F., Whelan, M.J. and Bieroza, M. (2010). Nitrate concentrations and fluxes in the River Thames over 140 years (1868–2008): Are increases irreversible? Hydrological Processes 24, 2657–2662.
5 Langton, S.D. (1990). Avoiding edge effects in agroforestry experiments; the use of neighbour‐balanced designs and guard areas. Agroforestry Systems 12(2), 173–185.
6 Lindenmayer, D.B. and Likens, G.E. (2010). The science and application of ecological monitoring. Biological Conservation 143, 1317–1328.
7 Oehlert, G.W. (2010). A First Course in Design and Analysis of Experiments. Saint Paul: University of Minnesota.
8 Peterson, R.G. (1994). Agricultural Field Experiments: Design and Analysis. Boca Raton, FL: CRC Press.
9 Shannon, D.K., Clay, D.E. and Kitchen, N.R. (eds). (2018). Precision Agriculture Basics. Madison, WI: ASA, CSSA, SSSA. doi:https://doi.org/10.2134/precisionagbasics
Конец ознакомительного фрагмента.
Текст предоставлен ООО «ЛитРес».
Прочитайте эту книгу целиком, купив полную легальную версию на ЛитРес.
Безопасно оплатить книгу можно банковской картой Visa, MasterCard, Maestro, со счета мобильного телефона, с платежного терминала, в салоне МТС или Связной, через PayPal, WebMoney, Яндекс.Деньги, QIWI Кошелек, бонусными картами или другим удобным Вам способом.
