Overview of the use of biochar from main cereals to stimulate plant growth

The total global food demand is expected to increase up to 50% between 2010 and 2050; hence, there is a clear need to increase plant productivity with little or no damage to the environment. In this respect, biochar is a carbon-rich material derived from the pyrolysis of organic matter at high temperatures with a limited oxygen supply, with different physicochemical characteristics that depend on the feedstock and pyrolysis conditions. When used as a soil amendment, it has shown many positive environmental effects such as carbon sequestration, reduction of greenhouse gas emissions, and soil improvement. Biochar application has also shown huge benefits when applied to agri-systems, among them, the improvement of plant growth either in optimal conditions or under abiotic or biotic stress. Several mechanisms, such as enhancing the soil microbial diversity and thus increasing soil nutrient-cycling functions, improving soil physicochemical properties, stimulating the microbial colonization, or increasing soil P, K, or N content, have been described to exert these positive effects on plant growth, either alone or in combination with other resources. In addition, it can also improve the plant antioxidant defenses, an evident advantage for plant growth under stress conditions. Although agricultural residues are generated from a wide variety of crops, cereals account for more than half of the world¿s harvested area. Yet, in this review, we will focus on biochar obtained from residues of the most common and relevant cereal crops in terms of global production (rice, wheat, maize, and barley) and in their use as recycled residues to stimulate plant growth. The harvesting and processing of these crops generate a vast number and variety of residues that could be locally recycled into valuable products such as biochar, reducing the waste management problem and accomplishing the circular economy premise. However, very scarce literature focused on the use of biochar from a crop to improve its own growth is available. Herein, we present an overview of the literature focused on this topic, compiling most of the studies and discussing the urgent need to deepen into the molecular mechanisms and pathways involved in the beneficial effects of biochar on plant productivity.This work was supported by the Spanish Government (PID2019-105924RB-I00 MCIN/AEI/10.13039/501100011033 and RED2018-102407-T) and the Castilla-La Mancha Government (SBPLY/17/180501/000287 and SBPLY/21/ 180501/000033) to CE. The laboratory received support from UCLM intramural funds, and ÁM-G was recipient of a PhD grant from Fundación Tatiana Pérez de Guzmán el Bueno. EU FEDER funds complemented all the grants

Evaluating soil nitrate dynamics in an intercropping dripped ecosystem using HYDRUS-2D.

The competition mechanisms between crop species for water and nutrients, especially nitrate (NO3-N), in intercropping ecosystems are still poorly understood. Therefore, an experiment involving high (300 kg ha-1 for corn and 250 kg ha-1 for tomato), medium (210 kg ha-1 for corn and 175 kg ha-1 for tomato), and low (150 kg ha-1 for corn and 125 kg ha-1 for tomato) N-fertilizer applications (HF, MF, LF, respectively) was conducted in the corn and tomato intercropping ecosystem during 2014 (a calibration period for modeling) and 2015 (a validation period for modeling). The modified HYDRUS-2D code was used to analyze soil NO3-N concentrations (SNC) in the middle between corn rows (Pc), between corn and tomato rows (Pb), and between tomato rows (Pt), NO3-N exchange in the horizontal direction between different regions, NO3-N leaching from the corn, the bare, and the tomato region, and N uptake by crops. Simulated SNCs were in good agreement with measurements, with RMSE, NSE, and MRE of 0.01-0.06 mg cm-3, 0.75-0.98, and 8.7-19.1%, respectively, during the validation period (2015). Average SNCs in the 0-40 cm soil layer were different between Pc, Pt, and Pb. Intensive NO3-N exchange in the horizontal direction occurred during the second stage (Day After Sowing [DAS] 37-113 in 2014; DAS 29-120 in 2015). NO3-N exchange between the corn and bare regions was lower than between the tomato and bare regions due to smaller concentration gradients. However, in the vertical direction, NO3-N leaching from the corn region in both years was 4.1 and 8.8 times larger, respectively, than from the tomato region under HF since NO3-N mainly moved from the tomato region to the corn region. Our results reveal the competition between corn and tomato for N and provide a rationale for formulating and optimizing different fertilizer regimes for different crops in the intercropping ecosystem

Biochar-plant interaction and detoxification strategies under abiotic stresses for achieving agricultural sustainability: A critical review

The unpredictable climatic perturbations, the expanding industrial and mining sectors, excessive agrochemicals, greater reliance on wastewater usage in cultivation, and landfill leachates, are collectively causing land degradation and affecting cultivation, thereby reducing food production globally. Biochar can generally mitigate the unfavourable effects brought about by climatic perturbations (drought, waterlogging) and degraded soils to sustain crop production. It can also reduce the bioavailability and phytotoxicity of pollutants in contaminated soils via the immobilization of inorganic and/or organic contaminants, commonly through surface complexation, electrostatic attraction, ion exchange, adsorption, and co-precipitation. When biochar is applied to soil, it typically neutralizes soil acidity, enhances cation exchange capacity, water holding capacity, soil aeration, and microbial activity. Thus, biochar has been was widely used as an amendment to ameliorate crop abiotic/biotic stress. This review discusses the effects of biochar addition under certain unfavourable conditions (salinity, drought, flooding and heavy metal stress) to improve plant resilience undergoing these perturbations. Biochar applied with other stimulants like compost, humic acid, phytohormones, microbes and nanoparticles could be synergistic in some situation to enhance plant resilience and survivorship in especially saline, waterlogged and arid conditions. Overall, biochar can provide an effective and low-cost solution, especially in nutrient-poor and highly degraded soils to sustain plant cultivation

Irrigation and soil management strategies to improve fruit tree response in limiting soil conditions

La transformació de terres marginals, juntament amb un augment dels processos de degradació del sòl (p. e. salinització) estan traslladant l'agricultura a sòls més desfavorables, fet que obliga al desenvolupament de noves estratègies de maneig dels cultius. Durant els últims anys s'han introduït noves estratègies de reg, com el reg localitzat enterrat (subsurface drip irrigation, SDI) o el reg deficitari controlat, tot i que resulta necessari avaluar la seva viabilitat i sostenibilitat quan són aplicades en sòls amb propietats físiques limitants. Alhora, l'ús d'esmenes orgàniques i les tècniques d’aeració forçada estan sorgint com a mètodes de recuperació de sòls a baix cost, que podrien millorar potencialment el rendiment dels cultius en situacions desfavorables. És important estudiar els efectes d'aquestes estratègies i tècniques sobre les propietats del sòl, així com en la fisiologia dels cultius i la seva productivitat, tot i que també sobre paràmetres de qualitat d'importància creixent en el sector fructícola, com el potencial de conservació de la fruita. L'objectiu general d'aquesta tesi ha estat el d'avaluar diferents estratègies de maneig del sòl i de reg, i estudiar els seus efectes en plantacions de presseguer i nectarina en sòls amb condicions físiques limitants.La transformación de tierras marginales, junto con un aumento de los procesos de degradación del suelo (p. ej. salinización) están trasladando la agricultura a suelos más desfavorables, lo que obliga al desarrollo de nuevas estrategias de manejo de los cultivos. Durante los últimos años se han introducido nuevas estrategias de riego, como el riego localizado enterrado (subsurface drip irrigation, SDI) o el riego deficitario controlado, a pesar de que resulta necesario evaluar su viabilidad y sostenibilidad cuando son aplicadas en suelos con propiedades físicas limitantes. Al mismo tiempo, el uso de enmiendas orgánicas y las técnicas de aireación forzada están surgiendo como métodos de recuperación de suelos a bajo coste, que podrían mejorar potencialmente el rendimiento de los cultivos en situaciones desfavorables. Es de suma importancia el estudiar los efectos de estas estrategias y técnicas sobre las propiedades del suelo, así como en la fisiología de los cultivos y su productividad, aunque también sobre parámetros de calidad de importancia creciente en el sector frutícola, como el potencial de conservación de la fruta. El objetivo general de esta tesis fue el de evaluar diferentes estrategias de manejo de suelo y riego, y estudiar sus efectos en plantaciones de melocotón y nectarina en suelos con condiciones físicas limitantes.Transformation of marginal land along with an increase of soil degradation processes (e.g. salinization) is moving the agriculture into more unfavorable soils, forcing the development of new management strategies. Subsurface drip irrigation (SDI) and deficit irrigation strategies have been widely studied although it is necessary to evaluate their feasibility and sustainability when applied in soils with limiting physical properties. At the same time, organic soil amendments and oxygation techniques are arising as low-cost soil reclamation methods that could potentially improve the crop performance under such situations. It is of paramount importance to study the effects of these strategies and techniques on soil properties as well as on crop physiology and productivity, but also on some quality parameters of growing importance in the fruit sector, such as fruit storability. The general aim of this thesis was to assess various soil management and irrigation strategies and study their effects on peach and nectarine orchards under limiting soil conditions

Irrigation Systems and Practices in Challenging Environments

The book Irrigation Systems and Practices in Challenging Environments is divided into two interesting sections, with the first section titled Agricultural Water Productivity in Stressed Environments, which consists of nine chapters technically crafted by experts in their own right in their fields of expertise. Topics range from effects of irrigation on the physiology of plants, deficit irrigation practices and the genetic manipulation, to creating drought tolerant variety and a host of interesting topics to cater for the those interested in the plant water soil atmosphere relationships and agronomic practices relevant in many challenging environments, more so with the onslaught of global warming, climate change and the accompanying agro-meteorological impacts. The second section, with eight chapters, deals with systems of irrigation practices around the world, covering different climate zones apart from showing casing practices for sustainable irrigation practices and more efficient ways of conveying irrigation waters - the life blood of agriculture, undoubtedly the most important sector in the world

Combined application of mulches and organic fertilizers enhance shallot production in dryland

ArticleThe objective of this study was to determine the type of mulch and organic fertilizer that can induce suitable changes in the microclimate and chemical properties of soil for the promotion of growth and yield of shallot on dryland. A factorial randomized block design experiment with two factors and three replications was constructed. The first factor was mulches consisting of rice straw, coconut husk, silver-black plastic mulch, and without mulch. The second factor was the organic fertilizers composed of either composted cow manure, Gliricidia leaf compost (each applied at 5 t ha-1 ), and no organic fertilizer. Among all treatments tested, straw mulch with 5 t ha-1 cow manure (L1P1) decreased the soil temperature from 36 °C to 30 °C and increasing the soil moisture from 7% to 37%. This, in turn, increased the cation exchange capacity by 24.32 meq 100 g -1 , pH by 6.83, C organic from 0.74 to 2.72%, C/N ratio by 13.27%, total N by 0.29%, total P from 20.02 to 28.86 mg 100 g -1 and K2O by 39.16 mg 100 g -1 . In addition, the growth and yield of shallot were positively affected, as assessed by plant height, leaf number, root length, root dry weight, total leaf area, number of bulbs per hill, bulb diameter, weight of fresh bulbs, and bulb yield. The yield of bulbs increased from 4.27 to 10.22 t ha-1 after L1P1 treatment. This study demonstrates the application of straw mulch and 5 t ha-1 cow manure could enhance the yield of shallot cultivation on drylands

Organic Farming to Mitigate Abiotic Stresses under Climate Change Scenario

Climate change is resultant from modern-day chemical agriculture, which is creating negative impacts on crop production. Global agriculture is now facing various problems arising due to abiotic stresses such as flood, drought, temperature extremes, light extremes, salinity, heavy metal stress, nutrient toxicity/deficiency. These stresses not only hamper the growth and production but also reduce the quality of crops through morphological, physiological, biochemical changes and synthesis of ROS. Further, they negatively impact on entire environment specially soil health. Deterioration of yield and quality often occurs due to lack of essential inputs to plants under abiotic stresses. Although plants adopt defensive mechanisms, such abiotic stresses need to be addressed properly with various eco-friendly organic farming approaches. Different organic inputs like organic manures, biofertilizers, bio-priming with micro-organisms, bio-stimulants (seaweed extracts, humic acid, micro-organisms, etc.), mulches, biochar are known to alleviate abiotic stresses under climate change scenario. Further, various organic agronomic practices viz. crop rotation, intercropping, tillage, sowing methods and time, nutrient, water and intercultural operations, use of PGPB, organic formulations, grafting, selection of resistant/tolerant varieties and other scientific/wise uses of organic inputs can mitigate/escape the negative impacts of abiotic stresses resulting in upliftment in crop production as well as the quality of produce

Biochar: An emerging recipe for designing sustainable horticulture under climate change scenarios

The interest in sustainable horticulture has recently increased, given anthropogenic climate change. The increasing global population will exacerbate the climate change situation induced by human activities. This will elevate global food demands and the vulnerability of horticultural systems, with severe concerns related to natural resource availability and usage. Sustainable horticulture involves adopting eco-friendly strategies to boost yields while maintaining environmental conservation. Biochar (BC), a carbon-rich material, is widely used in farming to improve soil physical and chemical properties and as an organic substitute for peat in growing media. BC amendments to soil or growing media improve seedling growth, increase photosynthetic pigments, and enhances photosynthesis, thus improving crop productivity. Soil BC incorporation improves abiotic and biotic stress tolerance, which are significant constraints in horticulture. BC application also improves disease control to an acceptable level or enhance plant resistance to pathogens. Moreover, BC amendments in contaminated soil decrease the uptake of potentially hazardous metals, thus minimizing their harmful effects on humans. This review summarizes the most recent knowledge related to BC use in sustainable horticulture. This includes the effect of BC on enhancing horticultural crop production and inducing resistance to major abiotic and biotic stresses. It also discuss major gaps and future directions for exploiting BC technology

Investigating the effect of different coir substrates on the growth, yield and biochemical constituents of tomato (Solanum lycopersicum var. Esculentum)

Fruit crops depend on the quality of the substrate for improved development, yield and nutrient content. To assure higher crop quality and to answer year-round market demand, most producers employ organic substrate for greenhouse crop cultivation. Due to its regenerative nature, coconut coir, an organic substate made from the mesocarp or exterior husk of coconut fruit, provides advantages not only for crop cultivation but also, by being renewable, for the environment as well. The goal of the study was to ascertain the impact of two coconut coir substrate types (Profit and Power) on the development, production and biochemical components of tomato fruit produced in a greenhouse setting. Evaluated elements included plant physiology and yield such as plant height, stem diameter, fruit length and count and harvest index as well as plant biochemical components such as fruit protein, carbohydrate, vitamin, lycopene, phenolic, flavonoid and nutrient content. Results indicated that tomato plant cultivation in coconut coir (Power) resulted in increased fruit number production and an increase in biochemical content such as vitamin C and lycopene compared to the other cultivation treatments. Cultivation in coconut coir (Profit) showed a relative increase in harvest index compared to the other treatments. Overall, growing tomatoes in coconut coir (Power) substrate increased yield, nutrient-dense fruit and farmers are urged to grow tomato fruit on this coconut coir to realise an increase in superior tomato crop output and increase in profit from tomato cultivation in a greenhouse environment. However, costs and availability in terms of quantity should be considered.Dibjalo tša dikenywa di laolwa ke boleng bja lefelo la go bjalela gore di gole bokaone, di enywe le go ba le phepo ya boleng. Bontši bja batšweletši ba kgetha go šomiša lefelo la tlhago go bjala dibjalo tša ka gare ga moago go netefatša gore go ba le boleng bjo bokaone go fihlelela nyakego ya mebaraka ngwaga ka moka. Faepa ya khokhonate ke lefelo la go bjalela leo le tšweletšwago ka tlhago leo le nago le magapi a ka ntle goba mesokhapo ya kenywa ya khokhonate ebile e bonwa e na le dikholego go tikologo ka lebaka la go šomišwa leswa ga yona. Maikemišetšo a dinyakišišo tše e bile go tseba seabe sa mehuta ye e fapafapanego ya lefelo la go bjalela la faepa ya khokhonate le a (e lego ya poelo le ya maatla) kgolo, tšweletšo le diteng tša dipayokhemikhale tša tamati ka seemong sa ntlo ya go bjalela. Dilo tše di fapafapanego tša go swana le palo ya dikenywa, dipalopalo mabapi le puno, dibithamene, le laesophine di ile tša sekasekwa. Dinyakišišo di utollotše gore faepa ya khokhonate (maatla) e bile le dipalo tše ntši tša dikenywa ge e bapetšwa le ditswaki tše dingwe tša mobu wa dibjalo. Dipalopalo mabapi le puno di bile tše kgolo go faepa ya khokhonate (poelo) ge go bapetšwa le ditswaki tše dingwe tša mobu wa dibjalo. Dikenywa tše di bjetšwego go faepa ya khokhonate (maatla) di bile le maemo a godingwana a dibithamene C le laesophine ge di bapetšwa le ditswaki tše dingwe. Ka fao, dipoelo tša dinyakišišo di laetša gore faepa ya khokhonate (maatla) e okeditše palo ya dikenywa ge go bapetšwa le ditswaki tše dingwe. Diteng tša dipayokhemikhale tša go swana le dibithamene le laesophine di bile godimo ka dikenyweng tša ditamati tšeo di bjetšwego go faepa ya khokhonate (maatla) go feta ditswaki tše dingwe. Bjale re ka tšea gore go bjala ditamati go lefelo la go bjalela la faepa ya khokhonate (maatla) go tla feletša ka tšweletšo ya godingwana le dikenywa tše di tletšego ka phepo. Balemi ba hlohleletšwa go bjala kenywa ya tamati ba šomišwa lefelo la go bjalela la faepa ya khokhonate (maatla) go hwetša puno ya godingwana, tšweletšo ya boleng le koketšo ya poelo ka fase ga maemo a ntlo ya go bjalela.Izitshalo zezithelo zincike kuwungqimba lokhethelo ukuze zikhule kangcono, isivuno kanye nezinga lokudla okunempilo. Abakhiqizi abaningi bakhetha ukusetshenziswa kokudla noma izindlela zokulima ezikhiqizwe noma ezibandakanya ukukhiqizwa ngaphandle kokusebenzisa umanyolo wamakhemikhali, ukuze kutshalwe izitshalo ezibamba ukushisa kubuye kuqinisekiswe ikhwalithi engcono ukuhlangabezana nesidingo semakethe unyaka wonke. Ifayiba yemvelo ekhishwe ekhobeni langaphandle likakhukhunathi iwumkhiqizo oyingqimba okhiqizwa ngokwemzelo ekhiqizwa ngokuphilayo equkethe ikhoba lwangaphandle noma ungqimba olune fayiba phakathi nendawo yesithelo sikakhukhunathi futhi ibhekwa njengenzuzo yemvelo ngenxa yemvelo yayo evuselelekayo. Inhloso yocwaningo kwakuwukuthola umthelela wezinhlobo ezahlukene zongqimba lwekhukhunathi (inzuzo namandla) ekukhuleni, ekuvuneni kanye nezakhi zamakhemikhali ezinto eziphilayo zesithelo sikatamatisi esitshalwe endaweni ebamba ukushisa. Izinguquko ezifana nenombolo yezithelo, inkomba yokuvuna, amavithamini, nelayikhophini ziye zahlolwa. Ucwaningo luveze ukuthi ifayiba yemvelo ekhishwe ekhobeni langaphandle likakhukhunathi (amandla) yayinezinombolo zezithelo eziningi uma kuqhathaniswa nezinye izindlela zokwelapha. Inkomba yokuvuna ibiphezulu kuyifayiba yemvelo ekhishwe ekhobeni langaphandle likakhukhunathi (inzuzo) uma kuqhathaniswa nezinye izindlela zokwelapha. Isithelo esikhuliswe ngaphansi kukakhukhunathi (amandla) sasinamazinga aphezulu kavithamini C kanye nelikhophini uma siqhathaniswa nezinye izindlela zokwelapha. Amakhemikhali ezinto eziphilayo ezifana namavithamini kanye ne-likhophini zaziphezulu esithelweni sikatamatisi esitshalwe ngaphansi kwekhoyili kakhukhunathi (amandla) kunezinye izindlela zokwelapha. Ngakho-ke kungatholakala ukuthi ukukhulisa utamatisi ngaphansi kongqimba lwefayiba yemvelo ekhishwe ekhobeni langaphandle likakhukhunathi (amandla) kuzoholela ekuvuneni okuphezulu kanye nezithelo eziminyene ezinomsoco. Abalimi bayakhuthazwa ukuthi balime isithelo sikatamatisi besebenzisa iungqimba lwefayiba yemvelo ekhishwe ekhobeni langaphandle likakhukhunathi (amandla) ukuze bathole isivuno esiphezulu, umkhiqizo osezingeni eliphezulu kanye nokwandisa inzuzo ngaphansi kwezimo zendawo ezibamba ukushisa.College of Agriculture and Environmental SciencesM. Sc. (Agriculture