Nursery Production of Pinus engelmannii Carr. with Substrates Based on Fresh Sawdust

Production of pine sawdust biochar supporting phosphate-solubilizing bacteria as an alternative bioinoculant in Allium cepa L., culture

We produced and characterised biochar made from Caribbean pine sawdust as raw material. The biochar (BC₅₀₀) was used as biocompatible support to co-inoculate phosphate solubilizing bacteria (PSB) (BC₅₀₀/PSB) on Allium cepa L., plants at a greenhouse scale for four months. The three biomaterials study included proximate analysis, elemental analysis, aromaticity analysis, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), adsorption studies at different pH and PSB stability as a function of time. The results indicated that BC₅₀₀ is suitable as organic support or solid matrix to maintain the viability of PSB able to solubilise P from phosphate rock (PR). The biofertilizer (BC₅₀₀/PSB) allows increasing germination, seedling growth, nutrient assimilation, and growth of Allium cepa L., because PSB immobilised on BC₅₀₀ promoted nutrient mobilisation, particularly P, during cultivation of Allium cepa L., at pots scale. The two treatments to evaluate the biofertilizer (BC₅₀₀/PSB) showed the highest concentrations of total P with 1.25 ± 0.13 and 1.38 ± 0.14 mg bulb^-1 in A. cepa L. This work presents the benefits of a new product based on bacteria naturally associated with onion and an organic material (BC₅₀₀) serving as a bacterial carrier that increases the adsorption area of highly reactive nutrients, reducing their leaching or precipitation with other nutrients and fixation to the solid matrix of the soil.

Graft survival of Pinus engelmannii Carr. in relation to two grafting techniques with dormant and sprouting buds

Developing methods for successfully grafting forest species will be helpful for establishing asexual seed orchards and increasing the success of forest genetic improvement programs in Mexico. In this study we investigated the effects of two grafting techniques (side veneer and top cleft) and two phenological stages of the scion buds (end of latency and beginning of sprouting), in combination with other seven grafting variables, on the sprouting and survival of 120 intraspecific grafts of Pinus engelmannii Carr. The scions used for grafting were taken from a 5.5-year-old commercial forest plantation. The first grafting was performed on January 18 (buds at the end of dormancy) and the second on February 21 (buds at the beginning of sprouting). The data were examined by analysis of variance and a test of means and were fitted to two survival models (the Weibull's accelerated failure time and the Cox's proportional hazards model) and the respective hazard ratios were calculated. Survival was higher in the top cleft grafts made with buds at the end of latency, with 80% sprouting and an estimated average survival time of between 164 and 457 days after the end of the 6-month evaluation period. Four variables (grafting technique, phenological stage of the scion buds, scion diameter and rootstock height) significantly affected the risk of graft death in both survival models. Use of top cleft grafts with buds at the end of the latency stage, combined with scion diameters smaller than 11.4 mm and rootstock heights greater than 58.5 cm, was associated with a lower risk of death.

The High Cost of the Low-Cost Polybag System: A Review of Nursery Seedling Production Systems

An important strategy for meeting global landscape restoration goals is nursery production of high-quality seedlings. Growing seedlings with attributes that promote post-planting survival and growth can be dramatically influenced by the nursery container system. In many countries, nurseries produce seedlings in polybags filled with excavated soil. These seedlings often develop deformed roots with limited fibrosity which can lead to poor survival and growth after outplanting. Polybags are initially inexpensive but using these single-use plastic containers accrues expenses that are often untracked. Comparisons among nursery production systems must account for factors such as container longevity, labor efficiency, and seedling field performance. A more holistic approach to account for environmental, economic, social, logistic, and cultural elements in the cost–benefit equation that influences nursery production systems is needed. Converting to a modern container system requires concomitant adjustments in nursery scheduling and culturing matched to the new stock type. Doing so provides an opportunity to align nursery production techniques and resulting seedling attributes with anticipated field conditions. This article describes and discusses the advantages and disadvantages of nursery production systems and provides recommendations and case studies to aid nurseries in improving seedling quality toward meeting restoration goals in a cost-effective and timely manner.