Compost and PGP-Based Biostimulant as Alternative to Peat and NPK Fertilization in Chestnut (Castanea Sativa Mill.) Nursery Production

Abstract

In forest nurseries, intensive use of non-renewable substrates such as peat and high application rates of chemical synthesis fertilizers lead to environmental problems and high susceptibility to biotic and abiotic stresses. This work aims to seek more sustainable crop management to help mitigate these problems, combining the substitution of peat by compost and the use of growth-promoting microorganisms (PGPs) as a fertilization tool. For this purpose, a trial was carried out to test the effectiveness of an agricultural waste compost and a biostimulant based on PGP microorganisms in the production of Castanea sativa plants in a forest nursery. This trial assessed the growth of plants, with both inputs separately and combined, and then studied the tolerance of chestnut seedlings to water deficit. The results showed that partial substitution of peat by compost is possible, but not complete, as the high levels of conductivity and pH generated by a high proportion of compost negatively affected plant growth. It was also noted that the application of the biostimulant enables the complete substitution of mineral fertilization. Moreover, at the end of the nursery phase, chestnut seedlings treated with the biostimulant showed the same or even better quality than chestnut seedlings obtained with conventional fertilization, also resulting in greater resistance to water deficit, based on the increase in root volume and the improvement of the physiological status. Changes observed in both quantity and composition of microbiota associated with chestnut rhizosphere after inoculation with PGPs were related to the improvement observed. In relation to water deficit resistance, a positive synergy was also observed with the combination of both inputs, since plants with full substitution of peat by compost combined with PGP-based fertilization showed the greatest drought resistance.

Use of Compost Based on Invasive Algae Rugulopteryx okamurae as a Peat Alternative in Nursery Growing Media

“…The initial electrical conductivity (EC) in all compost-based substrates values ranged between 4.27 (40CA) and 18.05 dS m −1 (80CHA), which was significantly higher than that of the control (1.32 dS m −1 ) (Table 3). It could also be observed that the EC was affected by the percentage of compost, increasing with the ratio of compost in the substrate, which is in line with previous results [17,24,32]. In addition, the EC changed depending on the type of compost incorporated into the potting media, with higher values in the CHA treatment, followed by CPA and CA.…”

“…The control treatment resulted in the lowest pH, followed by 40CA. As previously reported [16,17], the pH increased with an increase in the ratio of compost, with the 80CHA and 80CPA treatments having the highest values.…”

“…In the horticultural system, transplant production in nurseries is an essential component, since it allows one to obtain uniform and high-quality seedlings with efficient management of resources [14,15]. In nursery production, the quality of the growing media is one of the most influencing factors for obtaining high-quality seedlings [15,16], with peat being the most widely used potting medium in nurseries [10] thanks to its excellent physical, chemical, and biological properties for plant development [17]. Nevertheless, awareness of the high environmental impact associated with its use [10,18] and increases in its price [19] have encouraged the horticultural sector to look for eco-friendly and low-cost peat alternatives [10,19,20], and compost has been the most investigated one [16,18,[21][22][23][24].…”

“…Numerous studies have reported that compost can reduce the use of peat in potting media by a proportion of 20-50% by volume in horticultural and forest nursery production [17,22,25]. The high pH, high electrical conductivity (EC), and high concentration of potential phytotoxic elements in compost may limit the feasibility of using it as a potting medium [10].…”

Isolasi dan Respons Tumbuh Cendawan Mutualistik Akar pada Beberapa Tanaman Pangan dan Kehutanan

“…Struktur kolonisasi yang terbentuk pada pengamatan 6 MSI ialah hifa eksternal, apresorium, hifa internal, dan struktur menyerupai klamidospora (Gambar 4). Cendawan mutualistik akar mengkolonisasi secara internal akar tanaman dan mengeksplorasi lingkungan rizosfer untuk mengeksplorasi sumber karbon, berkompetisi untuk ruang, air, dan nutrisi sehingga dapat meningkatkan kapasitas kompetitif dan menguntungkan tanaman inang (Fuertes-Mendizábal et al 2021).…”