Integrated Plant Nutricion on the Recovery of a Decayed Pear (Pyrus communis cv Packam's Triumph) Orchard.

Integrated plant nutrition (IPN) is a concept in which organic matter (as source of carbon, nutrients, microorganisms, and organic substances), in combination with chemical fertilization, required, and appropriate, in terms of rates, sources and application time, stimulate the rhizogenesis process improving plant nutrition.

During the 2011/2012 and 2012/13 seasons, an experiment was performed to evaluate the effects of IPN on the recovery of a decayed orchard. Two treatments (T1: control, T2: IPN) were compared on trees of different initial vigor (very low, low, medium, and normal), in a factorial experiment, using a randomized design, with four replications. The orchard is planted on an alluvial soil of near neutral pH, low organic matter content and medium fertility, and is drip irrigated. The IPN treatment consisted on 20 ton/ha of compost, with chemical fertilization of 70 kg N/ha, 20 kg P₂O₅/ha/ and 66 kg K₂O/ha per season, respectively; the control treatment included only chemical fertilization.  Compost was produced from grape pomace and had 20 % C, a C/N ratio: 16:1, N-NO₃/N-NH₄=1.23, and a low content of trace elements, with the exemption of Cu. Compost was applied once each season, in band, by each tree, during winter time (July) each season; chemical fertilization was applied during the growing season. Management for recovery included absence of winter pruning in the first season, and pruning in the second one, and removal of all fruit set. Evaluations included: total shoot growth (>20 cm); root density; pruning weight; enzymatic activity in soil; mineral leaf contents; Normalized Difference Vegetation Index (NDVI), and SPAD readings. Nutrient indices were calculated by multiplying NDVI by the total nutrient content.

Results showed significant differences (p<0.05) between treatments for: root density, pruning weight, enzymatic activity in soil, NDVI, SPAD readings, Na, Zn and Cu leaf contents and nutrient indices for N, K, Ca, Mg, Cu and Zn, which were larger for the IPN management. FONDECYT 1130975