Spatial and temporal variation in soil inorganic n concentration, and soil test P and K, in red raspberry fields and implications for soil sampling strategies

Abstract

Spatial and temporal variation in soil inorganic N concentration, and soil test P and K, in red raspberry fields and implications for soil sampling strategies. Can. J. Soil Sci. 82: 355-364. Fertilizer is commonly applied as a band in red raspberry (Rubus idaeus L.) fields, resulting in complex spatial and temporal variation in soil inorganic N concentration, and in soil test P and K. The objectives of this study were to determine the spatial and temporal distribution of soil inorganic N in red raspberry fields receiving different N fertility treatments, to use the data to determine the most appropriate sampling strategies for estimating the quantity of soil inorganic N at various times during the growing season, and to evaluate the same sampling strategies for soil test P and K. Treatments were a control that received no manure or fertilizer N, 55 kg N ha -1 as urea or as Duration T60, a slow release N fertilizer, banded in mid-April, or 100 kg total N ha -1 as solid broiler manure broadcast or banded in early March, or banded in mid-April. Soil inorganic N was sampled at 10 interrow locations 8, 23, 38, 53, 68, 83, 98, 113, 128, and 143 cm from the crop row, and for 0-15, 15-30, and 30-60 cm depth, for four sampling dates for the control and urea treatments, and for 0-15 and 15-30 cm depth on one sampling date for the remaining treatments. Random sampling and four systematic sampling strategies were evaluated for their bias in estimating soil inorganic N concentration and soil test P and K, and with respect to the number of soil cores required to achieve a given precision and probability level combination. The random sampling strategy gave unbiased estimates of soil inorganic N and soil test P and K, however, the number of cores required to obtain a given precision at a given probability level were generally greater than for the systematic sampling strategies. The systematic sampling strategy involving sampling only in the crop row and in the centre of the inter-row, the current industry standard, gave expected values that could sometimes be substantially lower than the true value, and was therefore not recommended for use in raspberry fields. The best systematic sampling strategy used samples collected from the crop row, from the fertilizer band, from the centre of the inter-row, and from midway between the fertilizer band and the centre of the inter-row. [355][356][357][358][359][360][361][362][363][364]. Dans les cultures de framboise (Rubus idaeus L.), on applique souvent l'engrais en bandes, ce qui entraîne une variation spatiale et temporelle complexe du N inorganique ainsi que du dosage du P et du K dans le sol. L'expérience devait déterminer la répartition spatiale et temporelle du N inorganique dans les framboisières amendées de diverses manières avec un engrais azoté, servir à établir la meilleure technique d'échantillonnage pour estimer la quantité de N inorganique pendant la période végétative à partir des données recueillies et préciser l'utilité des stratégies d'échantillonnage pour le dosage du...

Spatial and temporal distribution of soil inorganic nitrogen concentration in potato hills

“…It should also be noted that the evaluation of sampling strategies done in this study underestimates the actual variability in estimating soil inorganic N concentration because the soil volume sampled during location sampling was much larger than would be sampled using a standard soil probe. Use of systematic sampling strategies to overcome spatial variation in soil inorganic N concentration has also been successful in other crops (Clay et al 1995;Zebarth et al 1999Zebarth et al , 2002a; however, elevation control was not an issue for these crops. The results of this study suggest that measurement of soil inorganic N concentration only from the centre of the hill (e.g.…”

“…Systematic sampling strategies for soil inorganic N concentration have been found to be as good as or better than random sampling for corn (Zea mays L.) (Clay et al 1995;Zebarth et al 1999) and red raspberry (Rubus ideaus L.) (Zebarth et al 2002a), whereas choice of sampling strategy had no significant effect on the estimate of soil inorganic N concentration after harvest in wheat (Triticum aestivum L.) when fertilizer N was applied as a band in spring (Mahler 1990).…”

Soil Inorganic Nitrogen Content and Indices of Red Raspberry Yield, Vigor, and Nitrogen Status as Affected by Rate and Source of Nitrogen Fertilizer

“…Soil profile inorganic N content was calculated by averaging across different row locations, correcting for soil bulk density, and accumulating across soil sampled depths and expressed in units of kg N ha 21 . Zebarth et al (2002) found that sampling from these row locations provided an unbiased estimate of soil inorganic N content in raspberry fields. Soil bulk density was determined by the soil core method for depths of 0-15, 15 -30, and 30-60 cm and was corrected for coarse fragments (.…”

Simulating Nitrate Leaching Profiles in a Highly Permeable Vadose Zone

“…This is a complex problem as it depends on the physiology of the crop and the water content state of the soil (meaning it also depends on irrigation). According to different researchers [24,25,41], during the growing season, the size of the plant changes. Thus, the demand by the plant for nitrogen may change.…”