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Cassava is a source of carbohydrates to more than 200 million people in Sub-Saharan Africa, even though its production is 6–8 t ha−1, which is below the highest world production of 36.4 t ha−1 in India. To address this yield gap and increase cassava’s availability, affordability, and adequacy, intensive but sustainable production is important. Additionally, being an emerging raw material in the animal feeds, pharmaceutical, beer industries etc., only increases its demand, however the current production levels cannot effectively sustain this. Therefore, this paper reviews: improvement in cassava yields per area under fertigation and banding of fertilizers, a common practice among many farmers; the advantage of fertilizer application on starch of the storage roots, which is the fundamental ingredient in most industries using cassava as a raw material; and the climate smart technologies for intensive sustainable cassava production. In the end, this review enhances knowledge about fertilizer application to cassava, both banding and fertigation, and expounds on effective intensive sustainable climate-smart production strategies.

The objective of this study was to determine the effect of phosphorus applied through fertigation on growth and root yield of cassava. This was achieved through a greenhouse pot-experiment ...

Response of cassava (Manihot esculenta Crantz) to fertigation as a form of nutrient delivery is unknown. The objectives of this study were to establish a balanced nutrition and to enhance agronomic nutrient use efficiency (ANUE) of cassava under fertigation. This study was conducted in the greenhouse and in the field. In both, the results showed a similar trend. There were six fertigation concentrations and three cassava varieties, selected for their duration of growth in the field. Shoot biomass of the long‐duration variety (Nalumino) was the highest, even though its dry root yield was the lowest (10.18 t ha⁻¹) among the varieties. In contrast, the medium‐duration variety (Kampolombo) produced the highest dry root yield (20.34 t ha⁻¹) and a lower shoot biomass. The highest root yield of the shortest‐duration variety (Mweru) was achieved at 200 mg N, 30 mg P, and 200 mg K L⁻¹ (155.0, 23.3, 155.0 kg N, P, K ha⁻¹), while Nalumino's was at 70 mg N, 7 mg P, and 70 mg K L⁻¹ (54.3, 5.4, 54.3 kg N, P, K ha⁻¹). ANUE and harvest index of these varieties declined as the fertigation concentrations increased. Additionally, the correlation between concentrations of N in the youngest fully expanded leaf (YFEL) blades and dry root yields was the lowest (R² = 0.5488), whereas P and K were R² = 0.7237 and R² = 0.8006, respectively, an indication that nutrient concentrations in the leaf, especially N, cannot easily be used to predict root yield. When cassava reaches nutrient sufficiency, mainly N, its accumulation in the leaf continues without significant increase in the root yield.

The linkage between K and the development of storage roots in root crops is partially understood, hence this experiment determined some of the mechanisms involved in cassava. The effects of 10, 40, 70, 100, 150 and 200 mg K l-1 fertigation on photosynthetic attributes, soluble carbohydrates, starch, metabolites, growth and yield were studied in a greenhouse. Storage root yield, number of storage roots, stomatal conductance and net photosynthesis reached maximum at 150 mg K l-1 . However, soluble carbohydrates and starch in the leaves significantly declined with an increasing concentration of K solution, similarly to the trend of glycerol in the leaves. Conversely, malic acid, citric acid and propionic acid gradually increased reaching maximum at 150, 150 and 70 mg K l-1 respectively. Combined, these results suggest that sugars were transported from the leaves to a stronger sink - the bulking storage roots. This and the increase of intermediate metabolites of tricarboxylic acid cycle provided the energy required for the bulking process and the development of the storage roots. Although the measured parameters indirectly link K to storage root development, they nonetheless form a basis for studies on direct interactions.

Cassava (M. esculenta Crantz), feeding countless people and attracting markets worldwide, is a model for traditional crops that need physiology-based fertigation (fertilization through irrigation) standards in intensive cultivation. Hence, we studied the effects of 10 to 200 mg L-1 nitrogen (N) fertigation on growth and yields of cassava and targeted alterations in their photosynthetic, transpiration, and carbohydrate management. We found that increasing irrigation N from 10 to 70 mg L-1 increased cassava's photosynthesis and transpiration, but supported only the canopy’s growth. At 100 mg N L-1 cassava reached a threshold of sugar in leaves (~47 mg g-1), began to accumulate starch and supported higher yields. Yet, at 200 mg N L-1, the canopy became too demanding and plants had to restrain transpiration, reduce photosynthesis, decrease carbohydrates, and finally lower yields. We concluded that the phases of cassava response to nitrogen are: 1) growth that does not support yields at low N, 2) productive N application, and 3) excessive use of N. Yet traditional leaf mineral analyses fail to exhibit these responses, and therefore we propose a simple and inexpensive carbohydrate measurement to guide a precise use of N.

Background Fertigation is a rare and an expensive method of fertilizer application to cassava, and hence there is a need to optimize its efficiency for profitability. This study's objective was to optimize root yield of cassava through fertigation using a logistic model. Results The field treatments were six fertigation concentrations against three cassava varieties, selected according to their maturity period. The logistic model predicted 52%, 116% and 281% benefit of fertigation for the varieties Mweru, Kampolombo and Nalumino, respectively. Furthermore, only half of the amount of fertilizer applied for Mweru was required to achieve twice the root yield of Kampolombo. During the experiment, an unknown importance of atmospheric temperature to cassava and its relationship to fertigation was observed. An elevation of 3.7 °C in atmospheric temperature led to 226%, 364% and 265% increase in root yield of Mweru, Kampolombo and Nalumino, respectively. Conversely, shoot biomass and root yield declined when the average atmospheric temperatures dropped by 3.6 °C. However, the cold temperatures affected the short-growth-duration (Mweru) and medium-growth-duration (Kampolombo) varieties earlier, 22 days after the drop, than the long-growth-duration variety (Nalumino) - 50 days after the drop. Conclusion Fertigation induced resilience of the shoot biomass production to cold which was most pronounced in the root yield of Mweru in response to the highest fertigation concentration. Thus, while fertigation improved cassava's resilience to cold, it only did so effectively for short-growth-duration variety, Mweru. Also, enhanced performance of cassava under increased atmospheric temperature indicated its importance as a climate-smart crop. © 2020 Society of Chemical Industry.

Plant growth and development is adversely affected by different kind of stresses. One of the major abiotic stresses, salinity, causes complex changes in plants by influencing the interactions of genes. The modulated genetic regulation perturbs metabolic balance, which may alter plant’s physiology and eventually causing yield losses. To improve agricultural output, researchers have concentrated on identification, characterization and selection of salt tolerant varieties and genotypes, although, most of these varieties are less adopted for commercial production. Nowadays, phenotyping plants through Machine learning (deep learning) approaches that analyze the images of plant leaves to predict biotic and abiotic damage on plant leaves have increased. Here, we review salinity stress related markers on molecular, physiological and morphological levels for crops such as maize, rice, ryegrass, tomato, salicornia, wheat and model plant, Arabidopsis. The combined analysis of data from stress markers on different levels together with image data are important for understanding the impact of salt stress on plants.

Soil salinity is a major constrain to crop production and climate change accelerates it. It reduces plant water potential, causes ion imbalance, reduce plant growth and productivity, and eventually leads to death of the plant. This is the case in potato. However, potato has coping strategies such as accumulation of proline, an osmoregulator and osmoprotector. In addition, leaching of salts below the root zone is preferred, exogenous application of ascorbic acid and growth hormones are practiced to combat salinity. Breeding and genetic engineering also play key roles in salinity management of potato. Varieties such as: Amisk, BelRus, Bintje, Onaway, Sierra, and Tobique were tolerant in North America, variety Cara in Egypt, Sumi in Korea and varieties Vivaldi and Almera in Mediterranean region. Transgenic lines of Kennebec variety, lines S2 and M48 also proved tolerance due to transcription factor MYB4 encoded by rice Osmyb4 gene.

Studies on the microbial symbionts and the resultant influence on crop growth and protection have yielded a number of technical interventions. To date, inoculants made up of different microsymbionts are widely utilized for production of legumes and cereal crops. Key among these is the Rhizobia spp. targeted for legumes, arbuscular mycorrhizae of Glomus, Ascomycota, and Basidiomycota spp., which can infect a range of crops and trees and atoxigenic Aspergillus flavus fungi for managing aflatoxin in maize and groundnuts. This chapter discusses the importance of rhizobia, mycorrhizae, and atoxigenic fungi in enhancing crop yield and food safety. A significant number of investments in inoculant production for biofertilizer and biosafety organisms have increased in the past 10 years. There prospects are bright, given the widespread use of inoculants on legumes to increase nitrogen fixation and the efficient use of fertilizers; growing mycorrhizae for nutrient and water acquisition and pest and disease protection in roots and aflatoxigenic fungi to reduce maize and groundnut contamination has increased the importance of starch (maize products) and protein (groundnut and other legumes) in human diets. Legumes also contribute directly to the nitrogen budget and cycle of mixed cropping systems on smallholder farms. Efficient and combined use of microbial symbionts in biological nitrogen fixation (BNF) and mycorrhiza technologies can contribute to reduced greenhouse gas emission from farmlands, an important step in mitigating climate change.

Irregular rainfall distribution has increased incidences of mid-season drought in Western Kenya despite high amount of annual rainfall. This experiment’s aim was to determine soil moisture content under soybean and grain yield during mid-season drought. The objective was evaluated at two agro-ecological zones using sowing dates as main-plots, conventional and no tillage as sub-plots and Nyala, SB19 and SB20, soybean varieties, as sub-sub-plots. Soil moisture content between tillage methods at R2 and R4 in long and short rains were similar in Kanduyi and Alupe. However, it was different between sowing dates, among varieties and among interactions. Soybean grain yield was high on sowing at two weeks after the onset of long and short rains in Kanduyi whereas in Alupe it was the contrary. Increases of 5.9% and 12.8% in soil moisture in long rains and short rains respectively at R2 led to grain yield gain of 47.8% and 27.2% respectively at Kanduyi. Therefore, sowing at the onset of rains in Alupe and at two weeks after the onset of rains in Kanduyi increases soil moisture at R2 and R4 and consequently mitigates mid-season drought.