Multiple nutrient stress in fruit crops : Road to soil health-mediated quality production

Abstract

Fruit crops by the virtue of their extended juvenility , sharply delineated crop phenological growth stages , and ability to produce biomass per unit use of inputs, higher than cereal crops , are infact more mechanistically tailored to tolerate multiple nutrient stress. Productivity of fruit crops depends essentially on two premier facts, nutrient balance and biological activity , provided optimum soil moisture is maintained . Though , fruit crops are highly microbes -responsive , but combination of microbes-mycorrhizas produced much better crop responses , an indication of nutrient-constraint-neutral production system.  Of late, paradigm shift from inorganic to organic manures-inorganic nutrients -microbes mediated associative crop response have aided in developing the far sustainable and climate -resilient fruit production system. Our long term data (2007-19) accrued on response of organic manures versus inorganic fertilizers   demonstrated that important soil quality indices like soil microbial diversity, soil microbial biomass nutrient,  and organic carbon partitioning displayed significant changes, but without much difference in quantum of fruit yield ( but coupled with a-grade size fruits ) when compared with purely  inorganic fertilizer schedule. Combination of inorganic fertilizers -vermicompost -microbial consortium aided in saving 30-40% of crop nutrient requirement without any compromise on fruit yield or quality , besides   lower rate of CO₂ release compared to inorganic fertilizers , an evidence of carbon deposited in passive soil organic carbon pool, in addition to reducing the fertilizer doses by 30-40% and elevating the  post-harvest shelf life of citrus fruits. We further introduced the concept of “rhizosphere hybridization” to harness the value -added benefits of nutrient -microbe synergy, besides providing better crop responsiveness to microbial consortium suiting to wide range of perennial fruits under both optimum as well as soil water deficit stress. Role of biochars ( more recalcitrant carbon source) and arbuscular mycorrhizas-mediated glomalins (glycoproteins) have to be  increasingly brought into the regular practice while addressing the multiple nutrient stress backed up with crop phenology -based 8-10 pulse fertigation schedules . These attempts could be  translated into developing a robust toolbox ( catering to 4R X 4W principles ) for addressing multiple nutrient stress on a mutually exclusive basis , provided current methods of diagnosis of soil fertility constraints en-route precision diagnosis.