Temperate fruit trees are a vital part of the economy of the Cundiboyacense highlands in Colombia. The nursery stage is important because it guarantees development at the final grow site. Little is known about the fertilization processes and nutritional dynamics of deciduous fruit trees in the early stages. This research aimed to evaluate the dynamics of N-P-K-Ca and Mg, along with SPAD units, in grafted plum (Prunus salicina) var. Horvin plants under the conditions of tropical highlands, which were evaluated at different growth points (cm), from grafting to transplant. The foliar N concentrations were the highest, followed by the K, P and Mg concentrations. Macronutrient concentrations in the first-stage of grafted nursery plants require nutritional balance for vegetative development and successful establishment at the definitive grow site.
Cadmium is a heavy metal that affects cell structures, such as walls and membranes, especially in the photosynthetic apparatus (PSII), chlorophylls, chloroplasts and stomata, producing losses in production quantity and quality. In addition, it is harmful to the health of humans and animals. The objective was to analyze the behavior of the relative chlorophyll index (SPAD units) and stomatal conductance in clone CCN-51 cacao plants every 45 days (45, 90, 135 and 180 days) after liming application. Four doses of a dolomite + agricultural gypsum mixture were applied, increasing Ca+2 saturation in the soil to 7, 8 and 9 cmolc kg-1. The control treatment did not have applications. The results indicated a reduction in SPAD units in the plants without liming, with high cadmium levels in the soil (3.3 mg kg-1), and there were no statistical differences in the other treatments, possibly because of edaphic factors such as pH, organic matter content and Al+3. The best stomatal conductance was observed with 7 cmolc kg-1 in the foliar gas exchange. Supersaturated liming applications efficiently reduce the losses in quality and quantity caused by the accumulation of cadmium in cacao plants.
The bulb onion is one of the most important agricultural products in Colombia. The productive conditions of the Riego del Alto Chicamocha (Boyaca) district are a regional and national benchmark for this market. The objective of this research was to evaluate four irrigation regimes in terms of production and irrigation water efficiency in bulb onion crops. This trial was in the municipality of Nobsa, village of Dicho (Boyaca). A completely randomized design with four treatments was used: irrigation regime with 150% evapotranspiration (Evt); moisture-based irrigation regime, detected with soil moisture sensors; irrigation regime with 100% Evt; irrigation regime with 60% Evt, along with four repetitions. Starting three weeks after transplant and for 11 weeks (77 days), the polar diameter (cm), equatorial diameter (cm), root length (cm), leaf length (cm), SPAD units, stomatal conductance and irrigation water use efficiency were determined. The irrigation regime with 100% Evt had the best performance in terms of the polar and equatorial diameters and the root and leaf lengths, which were reflected in the fresh weight at harvest. The irrigation regime with soil moisture values obtained from remote sensors, with lower amounts of applied water, had better values for the transformation of water to fresh mass, with 13.64 kg mm-1.
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