Estimating seasonal nitrogen dynamics in peach trees in response to nitrogen availability

Abstract

The PEACH computer simulation model of reproductive and vegetative growth of peach trees (Grossman and DeJong 1994) was adapted to estimate seasonal nitrogen (N) dynamics in organs of mature peach (Prunus persica (L.) Batsch cv. O'Henry) trees grown with high and low soil N availability. Seasonal N accumulation patterns of fruits, leaves, stems, branches, trunk and roots of mature, cropping peach trees were modeled by combining model predictions of organ dry mass accumulation from the PEACH model with measured seasonal organ N concentrations of trees that had been fertilized with either zero or 200 kg N ha(-1) in April. The results provided a comparison of the N use of perennial and annual organs during the growing season for trees growing under both low and high N availability. Nitrogen fertilization increased tree N content by increasing organ dry masses and N concentrations during the fruit growing season. Dry mass of current-year vegetative growth was most affected by N fertilization. Whole-tree N content of fertilized trees was almost twice that of non-fertilized trees. Although N use was higher in fertilized trees, calculated seasonal N accumulation patterns were similar for trees in both treatments. Annual organs exhibited greater responses to N fertilization than perennial organs. Estimated mean daily N use per tree remained nearly constant from 40 days after anthesis to harvest. The calculations indicated that fertilized trees accumulated about 1 g N tree(-1) day(-1), twice that accumulated by non-fertilized trees. Daily N use by the fertilized orchard was calculated to be approximately 1 kg N ha(-1), whereas it was approximately 0.5 kg N ha(-1) for the non-fertilized trees. During the first 25-30 days of the growing season, all N use by growing tissues was apparently supplied by storage organs. Nitrogen release from storage organs for current growth continued until about 75 days after anthesis in both N treatments.

Effects of spring soil nitrogen application on nitrogen remobilization, uptake, and partitioning for new growth in almond nursery plants

“…This demonstrated relationship between growth and currentyear N supply is consistent with results reported for peaches and other tree fruit species (Oland, 1959;Niederholzer et al, 2001;Rufat and DeJong, 2001). Compared with the performance of above-ground tissues, root growth showed differential responses to N fertilization ( Figure 2C), with dry weights from fertilized trees being slightly, but non-significantly (P>0.05), lower than those of the roots from the controls.…”

“…The internal remobilization from storage tissues provides the nitrogen needed for early new growth before significant root uptake occurs (Taylor and May, 1967;Titus and Kang, 1982;Millard and Neilsen, 1989). However, as the season progresses, root uptake of nitrogen plays a more important role in satisfying the tree N demand (Weinbaum et al, 1984a;Sanchez et al, 1990;Rufat and DeJong, 2001). N uptake by roots is also affected by environmental factors such as temperature, soil texture, etc.…”

Use of organic mulch to enhance water-use efficiency and peach production under limiting soil conditions in a three-year-old orchard

“…According to the leaf nutrient analysis (Table 4), fertigation led to an increase in N uptake since leaf N content in the MF treatment (3.3%) was greater than that of the M and C treatments (2.2 and 1.8%, respectively). N content values below 2.4% in a peach crop may be indicative of N deficiency (Johnson, 2008), while values around 2.5 and above are found to be normal in late peach cultivars under temperate conditions (Rufat & DeJong, 2001). Leaf P and K content were greater in the M and MF treatments than in C. In the latter treatment, these concentrations (0.11 and 1.41% for P and K, respectively) were in a deficiency range for a peach crop (Johnson, 2008).…”

Free amino acids in the xylem sap of pear trees during dormancy

“…Remobilization in temperate fruit trees has been identified as the main mechanism underlying the supply of N to new shoots, which may occur before or simultaneous with its absorption byroots (RUFAT & DeJONG, 2001). In Abbe' Fetel pear trees, for example, remobilization is the predominant source of N, contributing approximately 80% of total cost of the formation of leaves, flowers, and spurs (TAGLIAVINI et al, 1997).…”

“…In this manner, the initial growth of buds becomes almost entirely dependent on the N reserves of vegetative tissues, since the root system is only activated after the initiation of growth by new sprouts. Although few studies have described the dynamics of the process in detail, it is evident that the remobilization of N occurs before absorption by roots, at least in some species, such as apple (DONG et al, 2001), pear (QUARTIERI et al, 2002), peach (RUFAT & DeJONG, 2001) and cherry trees (GRASSI et al, 2002). One plausible explanation for the remobilization of N from vegetative parts before absorption from soil is the fact that air temperature increases more quickly than soil temperature at the beginning of spring, when rates of N mineralization and availability are still very low (MILLARD & GRELET, 2010).…”