The silicon (Si) percentage in the dry matter of plants is between 0.1% and 10%, and even though its role in the metabolism of plants is not absolutely clear, Si’s positive effects on plant nutrition and plant protection against both biotic and abiotic stress are well documented. However, Si is not considered to be an essential element, so it is not always present in nutrient solutions. In this paper, an experiment was carried out in the University of Almeria’s greenhouse with hydroponic lettuce, tomato, pepper, melon, and cucumber plants. A standard nutrient solution was used as a control sample and was fertigated with Si. During the four-true-leaf seedling stage, various plant growth parameters were measured, including the dry weight and the wet weight as well as the foliar surface and the cuticle thickness of both the leaf and the stem. Additionally, in the lettuce, tomato, and pepper plants, the effect of the use of Si in the nutrient solution on the protection against the pathogen Botrytis cinerea was determined by measuring the penetration of the pathogen through the cuticle and the extension of the fungal infection by using leaf discs. The results suggest that all of the studied parameters, and both the cuticle thickness and the epidermis thickness, were increased by more than 10% on average for all of the plants. In the lettuce, tomato, and pepper plants, a beneficial effect against B. cinerea was observed when the nutrient solution containing Si was used.
Volcanic rock has been used for decades as a horticultural substrate worldwide. In Spain, the use of this material as a substrate is ancient; it was initially used in the Canary Islands because of its volcanic geological origin. At the University of Almería (Almería, Spain), three independent vegetable crops were grown under greenhouse conditions: sweet pepper, tomato, and melon. The volcanic rock came from a location in the geographic center of Spain, which facilitated logistics. Bags of volcanic rock (25 L) were used and were compared with a commercial coconut fiber substrate of an equal volume. All physical, physical–chemical, and chemical parameters of the volcanic rock were determined using European standard analytical procedures. Fertigation was applied, independently adapted to the physical, physical–chemical, and chemical characteristics of each substrate. The cultures were performed under a randomized complete block experimental design. Fertigation parameters, pollutant emissions, fruit production, and the quality of each culture were measured. The results showed that the assessed parameters of the volcanic rock substrate are not a limiting factor for its use as a horticultural substrate. The resultant production and quality were very similar among the three crops compared with a widely used commercial control. Therefore, volcanic rock emerges as a local, sustainable alternative to be used for soilless crop cultivation.
Silicon (Si) asilimia katika suala kavu ya mimea ni kati ya 0.1% na 10%, na ingawa jukumu lake katika kimetaboliki ya mimea si wazi kabisa, Si athari chanya juu ya lishe mimea na ulinzi wa mimea dhidi ya mkazo biotic na abiotic ni vizuri kumbukumbu. Hata hivyo, Si haichukuliwi kuwa kipengele muhimu, kwa hiyo haipatikani kila wakati katika suluhisho la virutubisho. Katika karatasi hii, jaribio lilifanywa katika chuo kikuu cha Almeria cha chafu na hydroponic lettuce, nyanya, pilipili, melon, na mimea ya matango. Suluhisho la kawaida la virutubisho lilitumiwa kama sampuli ya udhibiti na lilitengenezwa na Si. Katika hatua ya mbegu ya majani manne ya kweli, vigezo mbalimbali vya ukuaji wa mmea vilipimwa, ikiwa ni pamoja na uzito wa kavu na uzito wa mvua, pamoja na uso wa majani na unene wa cuticle ya majani na shina. Kwa kuongezea, katika mimea ya lettuce, nyanya na pilipili, athari ya matumizi ya Si katika suluhisho la virutubisho juu ya ulinzi dhidi ya vimelea vya Botrytis cinerea ilitambuliwa kwa kupima kupenya kwa vimelea kupitia cuticle na upanuzi wa maambukizo ya kuvu kwa kutumia diski za majani. Matokeo ya utafiti huo yanaonyesha kwamba vipimo vyote vilivyochunguzwa, na pia unene wa kifuniko na unene wa epidermis, uliongezeka kwa wastani zaidi ya 10% kwa mimea yote. Katika mimea ya lettuce, nyanya, na pilipili, athari nzuri dhidi ya B. cinerea ilionekana wakati suluhisho la virutubisho lenye Si lilipotumiwa. Miamba ya volkano imetumiwa kwa miongo mingi kama msingi wa kilimo cha bustani ulimwenguni pote. Katika Hispania, matumizi ya nyenzo hii kama substrate ni ya kale; ilikuwa awali kutumika katika Visiwa vya Canary kwa sababu ya asili yake volkano kijiolojia. Katika Chuo Kikuu cha Almería (Almería, Hispania), mazao matatu ya mboga yalilimwa kwa kujitegemea chini ya hali ya chafu: pilipili tamu, nyanya, na melon. Jiwe hilo la volkano lilitoka mahali fulani katikati ya Hispania, jambo ambalo lilifanya iwe rahisi kupata vifaa. Mifuko ya mawe ya volkano (25 L) ilitumiwa na ikalinganishwa na substrate ya nyuzi za kokoni ya kibiashara ya kiasi sawa. Vipimo vyote vya kimwili, fizikia <unk> kemikali, na kemikali ya mwamba wa volkano vilitambuliwa kwa kutumia taratibu za uchambuzi za kiwango cha Ulaya. Fertigation ilitumiwa, kujitegemea ilichukuliwa kwa sifa za kimwili, kimwili <unk> kemikali, na kemikali ya kila substrate. Utamaduni ulifanywa chini ya randomized kamili block majaribio ya kubuni. Vigezo vya kuchaji, uzalishaji wa uchafuzi, uzalishaji wa matunda, na ubora wa kila utamaduni ulipimwa. Matokeo yalionyesha kwamba vigezo vilivyochunguzwa vya substrate ya mwamba wa volkano sio sababu ya kupunguza matumizi yake kama substrate ya kilimo cha bustani. Uzalishaji na ubora uliotokana ulikuwa sawa sana kati ya mazao matatu ikilinganishwa na udhibiti wa kibiashara unaotumiwa sana. Kwa hiyo, miamba ya volkano hutokea kama mbadala wa mahali hapo, endelevu wa kutumiwa kwa kilimo cha mazao bila udongo.