Drought stress, being the inevitable factor that exists in various environments without recognizing borders and no clear warning thereby hampering plant biomass production, quality, and energy. It is the key important environmental stress that occurs due to temperature dynamics, light intensity, and low rainfall. Despite this, its cumulative, not obvious impact and multidimensional nature severely affects the plant morphological, physiological, biochemical and molecular attributes with adverse impact on photosynthetic capacity. Coping with water scarcity, plants evolve various complex resistance and adaptation mechanisms including physiological and biochemical responses, which differ with species level. The sophisticated adaptation mechanisms and regularity network that improves the water stress tolerance and adaptation in plants are briefly discussed. Growth pattern and structural dynamics, reduction in transpiration loss through altering stomatal conductance and distribution, leaf rolling, root to shoot ratio dynamics, root length increment, accumulation of compatible solutes, enhancement in transpiration efficiency, osmotic and hormonal regulation, and delayed senescence are the strategies that are adopted by plants under water deficit. Approaches for drought stress alleviations are breeding strategies, molecular and genomics perspectives with special emphasis on the omics technology alteration i.e., metabolomics, proteomics, genomics, transcriptomics, glyomics and phenomics that improve the stress tolerance in plants. For drought stress induction, seed priming, growth hormones, osmoprotectants, silicon (Si), selenium (Se) and potassium application are worth using under drought stress conditions in plants. In addition, drought adaptation through microbes, hydrogel, nanoparticles applications and metabolic engineering techniques that regulate the antioxidant enzymes activity for adaptation to drought stress in plants, enhancing plant tolerance through maintenance in cell homeostasis and ameliorates the adverse effects of water stress are of great potential in agriculture.

There is a need for a more innovative fertilizer approach that can increase the productivity of agricultural systems and be more environmentally friendly than synthetic fertilizers. In this article, we reviewed the recent development and potential benefits derived from the use of nanofertilizers (NFs) in modern agriculture. NFs have the potential to promote sustainable agriculture and increase overall crop productivity, mainly by increasing the nutrient use efficiency (NUE) of field and greenhouse crops. NFs can release their nutrients at a slow and steady pace, either when applied alone or in combination with synthetic or organic fertilizers. They can release their nutrients in 40–50 days, while synthetic fertilizers do the same in 4–10 days. Moreover, NFs can increase the tolerance of plants against biotic and abiotic stresses. Here, the advantages of NFs over synthetic fertilizers, as well as the different types of macro and micro NFs, are discussed in detail. Furthermore, the application of NFs in smart sustainable agriculture and the role of NFs in the mitigation of biotic and abiotic stress on plants is presented. Though NF applications may have many benefits for sustainable agriculture, there are some concerns related to the release of nanoparticles (NPs) from NFs into the environment, with the subsequent detrimental effects that this could have on both human and animal health. Future research should explore green synthesized and biosynthesized NFs, their safe use, bioavailability, and toxicity concerns.

Global warming promotes soil calcification and salinization processes. As a result, soil phosphorus (P) is becoming deficient in arid and semiarid areas throughout the world. In this pot study, we evaluated the potential of phosphate-solubilizing bacteria (PSB) for enhancing the growth and P uptake in maize under varying levels of lime (4.8%, 10%, 15% and 20%) and additional P supplements (farmyard manure, poultry manure, single super phosphate and rock phosphate) added at the rate of 45 mg P2O5 kg−1. Inoculation and application of P as organic manures (Poultry and farm yard manures) improved maize growth and P uptake compared to the control and soils with P applied from mineral sources. Liming adversely affected crop growth, but the use of PSB and organic manure significantly neutralized this harmful effect. Mineral P sources combined with PSB were as effective as the organic sources alone. Furthermore, while single supper phosphate showed better results than Rock phosphate, the latter performed comparably upon PSB inoculation. Thus, PSB plus P application as organic manures is an eco-friendly option to improve crop growth and P nutrition in a calcareous soil under changing climate.

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Core Ideas Limited data on the effect of row width on defoliation in modern hybrids.Yield loss in 38 cm was less for all defoliation treatments vs. 76‐cm rows.Different hybrids responded differently to defoliation at different row widths.Defoliations had greater impact on kernel number than kernel weight in both hybrids.Some defoliations during effective grain‐filling period reduced kernel number. Corn (Zea mays L.) defoliation experiments have been conducted for more than 130 yr in the United States. However, there are limited data on the effect of row width on defoliation in modern hybrids. A 2‐yr experiment was conducted in Lexington, KY, with two hybrids (113 relative maturity [RM] and 120 RM), two row widths (38 and 76 cm) and a combination of defoliation timings and severities: 0% defoliation (control), V7 growth stage, and 100% defoliation (V7–100%), V14–50%, V14–100%, R2–50%, and R2–100%. No yield difference among hybrids was observed in 2012. Yields were 26% greater in 38‐cm rows than 76‐cm rows in 2012. For 2013, corn yield for 38 cm was 10% greater, but hybrid, row width, and defoliation interacted. Lowest yields were caused by V14–100% followed by R2–100% defoliations. Defoliations of V14–50% and R2–50% reduced yields in some cases. Complete defoliations at V7 did not reduce yields in most comparisons. Kernel number and kernel weight were most reduced by V14–100% and R2–100% defoliations, respectively. There is a potential for corn in 38‐cm narrow rows to reduce grain yield losses after a defoliation event, when compared with corn in 76‐cm standard rows.

Hail influence on corn (Zea mays L.) yield depends on defoliation timing and severity. Complete defoliation during early vegetative stages can have minimum yield effects if plants’ growing point is not affected but can generate some delays in the planting to flowering period. Low‐severity defoliations after V10 can reduce yield up to 30%. Higher severities gradually increase yield penalties to a peak around flowering and decrease progressively during the grain‐filling period. Charts to estimate the percentage of corn yield loss due to defoliation developed in the late 1960s are still accurate in most situations but fail to describe particular situations. Defoliation around VT commonly affects time to silking, anthesis–silking interval, and plant growth rate, but not time to anthesis, and is commonly explained by lower kernel number (KN). Defoliation at R2 commonly affects kernel weight (KW), without changing KN. However, several studies showed a reduction in both KW and KN with R2 defoliations. Under low plant disease pressure, fungicides applied around VT do not help reduce any yield defoliation impact. Specific genotypes, row spacing, and hybrid maturity can influence crop yield defoliation responses. More studies are warranted to confirm the potential for narrow rows to reduce yield loss after defoliation.

Biochar is gaining significant attention due to its potential for carbon (C) sequestration, improvement of soil health, fertility enhancement, and crop productivity and quality. In this review, we discuss the most common available techniques for biochar production, the main physiochemical properties of biochar, and its effects on soil health, including physical, chemical, and biological parameters of soil quality and fertility, nutrient leaching, salt stress, and crop productivity and quality. In addition, the impacts of biochar addition on salt-affected and heavy metal contaminated soils were also reviewed. An ample body of literature supports the idea that soil amended with biochar has a high potential to increase crop productivity due to the concomitant improvement in soil structure, high nutrient use efficiency (NUE), aeration, porosity, and water-holding capacity (WHC), among other soil amendments. However, the increases in crop productivity in biochar-amended soils are most frequently reported in the coarse-textured and sandy soils compared with the fine-textured and fertile soils. Biochar has a significant effect on soil microbial community composition and abundance. The negative impacts that salt-affected and heavy metal polluted soils have on plant growth and yield and on components of soil quality such as soil aggregation and stability can be ameliorated by the application of biochar. Moreover, most of the positive impacts of biochar application have been observed when biochar was applied with other organic and inorganic amendments and fertilizers. Biochar addition to the soil can decrease the nitrogen (N) leaching and volatilization as well as increase NUE. However, some potential negative effects of biochar on microbial biomass and activity have been reported. There is also evidence that biochar addition can sorb and retain pesticides for long periods of time, which may result in a high weed infestation and control cost.