Application of the “4R” Nutrient Stewardship Concept to Horticultural Crops: Getting Nutrients in the “Right” Place

Abstract

<jats:p>Right fertilizer placement is one of the 4Rs of an effective nutrient stewardship system and should be combined with considerations for the right fertilizer source, rate, and timing. Fertilizer placement decisions depend on mobility of applied nutrients in the soil and the depth and distribution of the crop's root system. Various methods are used to apply fertilizers to horticultural crops, including broadcasting, banding, fertigation, foliar application, and microinjection. Generally, the most appropriate method for any crop increases productivity and profitability and improves fertilizer use efficiency but varies depending on the nutrient element, fertilizer source, soil characteristics, cultural practices, stage of crop development, weather conditions, and farming enterprise constraints. Comparisons among application methods are available for many crops and provide useful information for improving fertilizer placement practices, but many practical questions such as how fertilizer source and availability are affected by irrigation interactions or whether there are ways to manage crop roots for more effective nutrient uptake still remain.</jats:p>

Chemigation with Micronized Sulfur Rapidly Reduces Soil pH in a New Planting of Northern Highbush Blueberry

“…Strik and Vance (2015) also reported low leaf P in various cultivars of northern highbush blueberry in western Oregon, but the concentrations measured in the present study in year 2 were below those reported previously for 'Duke' (Larco et al, 2013b;Strik and Vance, 2015). Phosphorus uptake is sometimes limited in fertigated plants because of the smaller size of the root system (Bryla, 2011).…”

Comparison of the hydrolysis characteristics of three polyphosphates and their effects on soil phosphorus and micronutrient availability

“…Unfortunately, orthophosphate‐based fertilizers have obvious drawbacks in terms of the bioavailability of P when they are added to soils because the P in phosphate () form is easily adsorbed by soil clay particles and precipitated by soil cations (Mamedov et al., ). Farmers have attempted to cope with this problem by (a) using appropriate P sources (i.e., liquid instead of granular phosphate fertilizer; McLaughlin, Bertrand, Lombi, Holloway, & Johnston, ; Wang & Chu, ); (b) applying phosphate fertilizer in split applications (Bryla, ); and (c) applying phosphate fertilizer with manure (Sisr, Mihaljevič, Ettler, Strnad, & Šebek, ). However, none of these approaches can overcome the inherent disadvantages of orthophosphate‐based P fertilizers.…”

Irrigation and Fertigation with Drip and Alternative Micro Irrigation Systems in Northern Highbush Blueberry

“…Yield was also similar among these treatments the following year. While it was not measured in the study, the root systems of the plants were likely much larger by the beginning of the second season than in the previous year, and roots were probably concentrated near the drip emitters (Bryla, 2011b). If so, more of the N applied through the drip system would have been available for root uptake and, therefore, would explain why less N (i.e., 100 kg · ha -1 ) was needed in plants fertigated by drip during the latter 2 years of the study.…”

“…1). Irrigation was controlled independently in each treatment using electric solenoid valves and an automatic timer and was scheduled three to seven times per week, based on precipitation, plant size, and weekly estimates of potential and crop evapotranspiration obtained from a local Pacific Northwest Cooperative Agricultural Weather Network AgriMet weather station (http://usbr.gov/pn/agrimet) (Bryla, 2011a). All treatments were irrigated on the same day each week.…”