Dipartimento di Colture Arboree, viale Fanin 46, 40127 Bologna, Italy.
Tree Physiol. 2010 Nov;30(11):1373-82. doi: 10.1093/treephys/tpq078. Epub 2010 Oct 4.
We evaluated the effects of mineral and organic fertilizers on peach root dynamics in the growing season from 2003 to 2006 in a nectarine (Prunus persica L.) orchard, planted in 2001 and located in the Po valley, northeastern Italy. Very few studies have conducted long-term investigations of root dynamics of fruit crops. Our main objective was to determine whether organic fertilizers affect root dynamics differently than mineral fertilizers. The experiment was a completely randomized block design with four replicates of three treatments: unfertilized, mineral fertilized and composted with municipal waste. Mineral fertilizers included P (100 kg ha(-1) year(-1)) and K (200 kg ha(-1) year(-1)) applied only at planting and N (70-130 kg ha(-1) year(-1)) split into two applications, one at 40 days after full bloom (60%) and the other in September (40%) each year. The compost fertilization represented a yearly rate of 10 metric tons (t) dry weight ha(-1), which approximates (in kg ha(-1) year(-1)) 240 N, 100 P and 200 K, split similarly to that described for the mineral fertilization of N. Both root growth and survival were evaluated at 20-day intervals during the growing season by the minirhizotron technique. Compost increased the production of new roots compared with the other treatments (P < 0.01). Roots were mainly produced at a depth of 41-80 cm and from March to May and in late summer. An analysis of covariance indicated no significant effect of soil nitrate on root production (P = 0.47). The root lifespan was longer in compost-treated trees than in mineral-fertilized or unfertilized trees (P < 0.01) and it was strongly affected by time of birth; roots born later in the summer lived longer than those born in the spring. Across years and treatments, the average root lifespan was positively correlated with soil nitrate (r = 0.60; P < 0.001). Variation in root lifespan with method of fertilization could be accounted for by variation in soil nitrate concentration as indicated by no effect of fertilizer treatment on root lifespan when soil nitrate was included as a covariate. These results reveal how shifting from mineral to organic fertilizers may shift both soil properties and nutrient availability, leading to changes in both root production and lifespan.
我们评估了 2003 年至 2006 年期间矿物肥和有机肥对桃树根系动态的影响，该试验在意大利东北部波河谷的一片油桃（Prunus persica L.）果园中进行，果园于 2001 年种植。很少有研究对果树枝条的根系动态进行长期调查。我们的主要目标是确定有机肥是否会对根系动态产生不同于矿物肥的影响。该试验采用完全随机区组设计，有四个重复，三种处理：不施肥、矿物肥和城市垃圾堆肥。矿物肥包括种植时施入的 P（100 kg/ha/年）和 K（200 kg/ha/年）以及每年分两次施入的 N（70-130 kg/ha/年），其中 60%在盛花后 40 天施入，40%在 9 月施入。堆肥施肥量为每年 10 吨干重/公顷，相当于（kg/ha/年）240 N、100 P 和 200 K，与矿物肥中 N 的施肥方式相似。在整个生长季，我们每 20 天用 minirhizotron 技术评估一次新根的生长和存活情况。与其他处理相比，堆肥增加了新根的产生（P<0.01）。根系主要在 41-80 cm 的深度产生，从 3 月到 5 月和夏末产生。协方差分析表明，土壤硝酸盐对根的产生没有显著影响（P=0.47）。与矿物肥或不施肥的树相比，堆肥处理的树的根寿命更长（P<0.01），并且受出生时间的强烈影响；夏季后期出生的根比春季出生的根寿命更长。在不同年份和处理中，平均根寿命与土壤硝酸盐呈正相关（r=0.60；P<0.001）。如将土壤硝酸盐作为协变量包含在内，施肥处理对根寿命没有影响，这表明，根寿命的变化可以用土壤硝酸盐浓度的变化来解释。这些结果揭示了从矿物肥向有机肥的转变如何改变土壤特性和养分供应，从而导致根系的产生和寿命发生变化。
