In view of the celebration of the ‘International Year of Millets,’ millets are popularizing sustainable agricultural output amid challenging climates and nourishing adequately as food and feed. The extent of scientific intervention is the foundation for designing, promoting and popularizing neglected crops on social platforms. Planning future directions and adaptive strategies largely require regular evaluation of research efforts to identify hotspots and research gaps, as identified in the present study by creating a robust text-mining approach that integrates scientometrics using PubMed citation data. Keyword mining reveals that India and China are the leading publication centres on millets, possibly due to their large proportion of cultivation and indigenous nature. It further reveals that the pearl millet is the predominant one, followed by foxtail and finger millet, suggesting that most research is confined to them only; however, other millets, still have a research gap in comparison. The word abiotic stress is associated with high frequency in millet research due to its adaptive nature amid climate change. Thematic representation explored the novel concept of millet's utility as a probiotic and millet bran to ensure nutrient–cereal properties based on the persistency of keywords throughput research progression; however, incurious consumption is associated with harmful ochratoxin. Bio-concept mining and knowledge graph generation divided the millet research output into four large domains, which provides a largely covered bio-concepts for millet research and co-concurrence of emerging bio-concepts to intense progress and finds an adequate literature gap to improve millet research for sustained growth and equilibrate biodiversity.

Planning future directions and adapting approaches for seed improvement in underutilized crops requires the assessment of research activities. We have examined the trends and research activities conducted on seed improvement of underutilized crops. We identified research hotspots based on keywords and prolific research titles mapped across three decades (1990 to 2021). Data were compiled using Google Scholar, Web of Science and Scopus databases, loaded into the bibliometric R-package and viewed via VOSviewers software. In research on seed improvement among underutilized crops (SUC), we have observed 7.2% annual growth in publication and increase in the studies and citations. There were strong research publications with strong research links from studies conducted in USA, Canada, India, Nigeria and China, while South Africa and Egypt were among the African countries with high research studies in SUC. Among underutilized crops with improvement among their seed traits are sorghum, quinoa, Bambara groundnut, amaranth, barley, tef, cowpea and millet. Some of the trending research areas are genetic diversity, seed performance, seed domestication, yield, crop management, water use efficiency, nutritional properties, molecular strategies and genetic analysis tools for seed improvement. There is gradual increase for international collaborations and funding in SUC studies. The current research emphases are on qualitative studies, appropriate methodological procedures and advanced breeding resources to help understand and promote seed improvement among underutilized crops.

Fonio is an identity and orphan cereal of Africa whose production system has remained traditional. This work assessed the responses of selected genotypes of fonio to different sowing methods in Benin from 2018 to 2019. Split plot design with three replicates was used. Four genotypes from mass selection and two control varieties were randomly arranged in four planting modalities (ordinary broadcast sowing, continuous row sowing at inter-rows 20 cm (SLC20) and 25 cm (SLC25) and in seed hole sowing (SP25 × 20)). Agro-morphological data were collected and subjected to variance and multivariate analyses. On all traits, interaction (variety × sowing × year) was not significant. Other interactions (variety × sowing, variety × year, sowing × year) were significant on some morpho-phenological traits. Genotypes AS19-1-1, AS1 and ‘Yoro’ were the earliest, especially AS19-1-1 presenting sowing–heading cycle less of 65 days. Improved genotypes were the most grain yielding mainly AS15-1-1 (1056.5 kg/ha) showing an excess of 405.9 kg/ha compared to control ‘Yoro’ (650.9 kg/ha), the least performing. However, control ‘Iporawan’ was the most yielding in dry matter (>8000 kg/ha). Based on sowing methods, plant density was negatively correlated with tiller number. The best growth and grain yield performances were obtained in broadcast sowing and especially in SLC25 (911.4 kg/ha). Cropping systems in which the new genotypes (AS1, AS13-1, AS15-1-1, 19-6-1-1) sown in continuous rows at 20–25 cm apart, or by broadcasting, were better in terms of grain yield (971.7 kg/ha). These systems constitute cultivation innovation which will enable to optimize fonio production and bring added value.

The aim of this work was to verify the possibility of intercropping rice with green manures, as well as the impact of the dry biomass yield of these intercropping systems on common bean in succession, evaluating the agronomic and qualitative performance of grains from both crops. The experiment was conducted in Southeastern Brazil in the years 2018 and 2019, with succession of rice (spring/summer) and common bean (autumn/winter). The treatments were composed of cropping systems with rice as a sole crop and intercropped with forage peanut, calopo, Crotalaria breviflora, Crotalaria spectabilis, stylo, jack bean and dwarf pigeon pea. No intercropping increased the system's yield compared to sole-crop rice, but intercropping of rice with forage peanut and stylo promoted grain yield and quality similar to those of sole-crop rice. Intercropping with C. breviflora affected the agronomic and qualitative performance of rice. Common bean yield after rice intercropped with dwarf pigeon pea, C. spectabilis and C. breviflora was similar in yield after sole-crop rice, while the other intercrops reduced common bean yield. Common bean grain quality was not affected by the cultivation of rice as sole crop and intercropped with green manures. Although none of the intercropping systems increased yield compared to sole-crop rice (control), it can be concluded that the intercropping of upland rice is viable depending on the green manure species, allowing greater biomass production per area that can help long-term soil conservation and increase the system's yield.

Introducing cover crops (CC) in annual cropping systems can promote nutrient cycling and improve soil health. However, impacts of CC on soil health indicators vary and depend on the duration of CC, cropping systems, and other environmental conditions. We performed an on-farm assessment of cover cropping impacts on soil health indicators including C and N pools, enzyme activities, and microbial community structure under different no-till maize-based cropping systems (maize (Zea mays L.)–soybean (Glycine max L.) [CS], CS-winter wheat (Triticum aestivum L.) [CSWw], and maize-oats (Avena sativa L.) [CO]). At five farms, fields with different durations of CC were compared to adjacent no CC (NCC) fields. In general, long-term CC enhanced the soil health parameters compared to NCC. Long-term (20-year) winter rye CC had higher water-extractable C and N content, enzyme activities (β-glucosidase (1.2 times greater), urease (5.5 times greater), acid (1.5 times greater) and alkaline (4 times greater) phosphatase, arylsulfatase (0.8 times greater) and fluorescein diacetate (FDA) (0.7 times greater)) and soil bacterial community abundance (1.2 times greater). Short-term (3–6 years) legume and grass CC mixtures increased β-glucosidase (0.9 times), acid (0.7 times) and alkaline (1.5 times) phosphatase, arylsulfatase (3 times), FDA (0.8 times) activities and total phospholipid fatty acid (1.6 times) concentration. However, short-term (3–6 years) winter rye, legume and brassica mixtures did not significantly alter soil microbial community structure. This study showed that implementation of CC for >6 years promoted C, N, S, and P cycling that are beneficial to soil health in maize-based cropping systems.

Pearl millet (Pennisetum glaucum (L.) R.) is an important crop for rainfed production systems and can play a significant role as a feed source for ruminants owing to its high yield and drought tolerance. It is well-established that the maturity stage can influence the chemical composition as well as the nutritional value of crops traditionally used for silage production, although quantitative evidence that this occurs with pearl millet under rainfed conditions is lacking. The current research assessed the agronomic characteristics, ensilability, intake and digestibility of a Brazilian pearl millet cultivar (IPA BULK1-BF) harvested at four different growth stages. Forage was harvested at 35, 50, 65 and 80 days after sowing and ensiled under laboratory and farm conditions. Apparent digestibility of the silages was determined using 24 male lambs. The results showed that dry matter (DM) and panicle and stem proportions increased with the advancement maturity. The silage evaluations showed that DM, total and non-fibrous carbohydrates and lignin concentrations increased, while crude protein, ADF and in vitro DM digestibility decreased with the increase in plant maturity. Additionally, the fermentation characteristics were improved with the increasing maturity. The digestion study showed that intake of DM and N as well as digestibility of DM and fibre fractions decreased, while lignin intake increased. The results obtained for the production of dry and digestible DM, the ratio of plant fractions and fermentation parameters indicate the possibility of harvesting pearl millet forage after 50 days after sowing for silage production in the Brazilian semi-arid region.

Agriculture in the Central Himalayan Region depends on the availability of suitable germplasm as well as natural conditions. Due to extreme weather conditions, food and nutrition security is a major issue for communities inhabiting these remote and inaccessible areas. Millets are common crops grown in these areas. Foxtail millet (Setaria italica (L.) P. Beauv) is an important crop and forms a considerable part of the diet in this region. The aim of the present study was to explore, collect, conserve and evaluate the untapped genetic diversity of foxtail millet at the molecular level and discover variability in their nutritional traits. A total of 30 accessions having unique traits of agronomic importance were collected and molecular profiling was performed. A total of 63 alleles were generated with an average of 2.52 alleles per locus and average expected heterozygosity of 0.37 ± 0.231. Significant genetic variability was revealed through the genetic differentiation (Fst) and gene flow (Nm) values. Structure-based analysis divided whole germplasm into three sub-groups. Rich variability was found in nutritional traits such as dietary fibre in husked grains, carbohydrate, protein, lysine and thiamine content. The collected germplasm may be useful for developing nutritionally rich and agronomically beneficial varieties of foxtail millet and also designing strategies for utilization of unexploited genetic diversity for food and nutrition security in this and other similar agro-ecological regions.

Plant height and lodging resistance can affect rice yield significantly, but these traits have always conflicted in crop cultivation and breeding. The current study aimed to establish a rapid and accurate plant type evaluation mechanism to provide a basis for breeding tall but lodging-resistant super rice varieties. A comprehensive approach integrating plant anatomy and histochemistry was used to investigate variations in flexural strength (a material property, defined as the stress in a material just before it yields in a flexure test) of the rice stem and the lodging index of 15 rice accessions at different growth stages to understand trends in these parameters and the potential factors influencing them. Rice stem anatomical structure was observed and the lignin content the cell wall was determined at different developmental stages. Three rice lodging evaluation models were established using correlation analysis, multivariate regression and artificial radial basis function (RBF) neural network analysis, and the results were compared to identify the most suitable model for predicting optimal rice plant types. Among the three evaluation methods, the mean residual and relative prediction errors were lowest using the RBF network, indicating that it was highly accurate and robust and could be used to establish a mathematical model of the morphological characteristics and lodging resistance of rice to identify optimal varieties.

Maize (Zea mays L.) is a major staple food and cash crop in sub-Saharan Africa (SSA). However, its production and productivity are severely constrained by drought. A total of 120 single-cross hybrids and an open-pollinated control variety were evaluated for 2 years at two locations under managed drought and rain-fed conditions in Nigeria. The objective of the present study was to assess their performance, classify them into distinct heterotic groups and identify promising hybrids for commercialization in the West and Central Africa sub-region. General combining ability and specific combining ability mean squares were highly significant for grain yield and other traits under the research environments. However, there was a preponderance of additive gene action over non-additive. Only six out of 39 inbreds were classified into distinct heterotic groups by the testers. The highest-yielding drought-tolerant hybrid, TZEEI 102 × TZEEI 95, out-yielded the open-pollinated control variety by 43·70%. The average yield reduction under drought was 54·90% of the yield under rain-fed conditions. The hybrids TZEEI 81 × TZEE1 79, TZEEI 100 × TZEEI 63 and TZEEI 64 × TZEEI 79 were the highest-yielding and most stable across environments. These outstanding drought-tolerant hybrids, which are also resistant to Striga, have the potential to contribute to food security and increased incomes in SSA and should be tested extensively on-farm and commercialized.

The mountain ecosystem of the Central Himalayan Region is known for its diversity of crops and their wild relatives. In spite of adverse climatic conditions, this region is endowed with a rich diversity of millets. Hence, the aim of the present study was to explore, collect, conserve and evaluate the diversity of barnyard millet (Echinochloa frumentacea) to find out the extent of diversity available in different traits and the traits responsible for abiotic stress tolerance, and to identify trait-specific accessions for crop improvement and also for the cultivation of millets in the region as well as in other similar agro-ecological regions. A total of 178 accessions were collected and evaluated for a range of morpho-physiological and biochemical traits. Significant variability was noted in days to 50% flowering, days to 80% maturity, 1000 seed weight and yield potential of the germplasm. These traits are considered to be crucial for tailoring new varieties for different agro-climatic conditions. Variations in biochemical traits such as lipid peroxidation (0·552–7·421 nmol malondialdehyde formed/mg protein/h), total glutathione (105·270–423·630 mmol/g fresh weight) and total ascorbate (4·980–9·880 mmol/g fresh weight) content indicate the potential of collected germplasm for abiotic stress tolerance. Principal component analysis also indicated that yield, superoxide dismutase activity, plant height, days to 50% flowering, catalase activity and glutathione content are suitable traits for screening large populations of millet and selection of suitable germplasm for crop improvement and cultivation. Trait-specific accessions identified in the present study could be useful in crop improvement programmes, climate-resilient agriculture and improving food security in areas with limited resources.

The adequate management of soil acidity has long been a challenge in no-till (NT) cropping systems. Some studies conducted in sub-tropical conditions have demonstrated the feasibility of surface liming. However, for tropical regions with dry winters, little long-term information about adequate rates and frequencies of application is available. A 12-year field trial was performed under a tropical no-tillage system with an annual crop rotation scheme. The treatments were composed of four lime rates (0, 1000, 2000 and 4000 kg/ha), estimated via the base saturation (BS) method. Surface application of lime was found to be an effective method for improving the soil fertility profile under this long-term NT cropping system. All three acidity components (pH, hydrogen + aluminium (H + Al), exchangeable Al) and some fertility attributes (phosphorus, exchangeable calcium and magnesium, and BS) were adjusted to a linear function, and better soil chemical conditions were obtained in the 4000 kg/ha treatment, even 4 years after the final application. Due to soil chemical changes, the root length density of wheat and common bean was greater at depths <0·20 m, which led to a higher grain yield, even under unfavourable weather conditions. The results indicate that the application of lime at higher rates can be an acceptable criterion for a tropical Oxisol under a no-tillage system, reducing the frequency of lime application.

APETALA2/ethylene-responsive factor (AP2/ERF) family transcription factors play a vital role in plant growth and in response to hormones and abiotic stresses. In the current research, it is reported that OsDERF2, one of the drought-responsive ERF, is a member of the DREB sub-family. OsDERF2 is a nuclear-localized protein and has transcriptional activity in yeast. Expression of OsDERF2 was induced by drought and inhibited by abscisic acid (ABA). However, OsDERF2 RNA interference (RNAi) knock-down transgenic lines enhanced tolerance to drought stress at seedling stage and were much more sensitive to ABA treatment, which may result from the increased ABA level in vivo. The basic leucine zipper (bZIP) transcription factor family plays an important role in the ABA signalling pathway of abiotic stress. Quantitative real-time polymerase chain reaction analysis revealed that the bZIP family gene OsbZIP20 and ABA-response gene OsABA45 were up-regulated 25 times and 120 times, respectively, in OsDERF2 RNAi knock-down lines under drought stress, which were up-regulated five and seven times in wild type under drought stress. The current data reveal that OsDERF2 negatively modulates drought stress response in an ABA-mediated pathway through regulating gene expression of other ABA-response transcription factors.

Foxtail millet (Setaria italica (L.) P. Beauv.) is a naturally stress-tolerant plant, a major reserve crop and a model for panicoid grasses. The recent completion of the S. italica genome facilitates identification and characterization of WRKY transcription factor family proteins that are important regulators of major plant processes, including growth, development and stress response. The present study identified 103 WRKY transcription factor-encoding genes in the S. italica genome. The genes were named SiWRKY1–SiWRKY103 according to their order on the chromosomes. A comprehensive expression analysis of SiWRKY genes among four different tissues was performed using publicly available RNA sequencing data. Eighty-four SiWRKY genes were more highly expressed in root tissue than in other tissues and nine genes were only expressed in roots. Additionally, real-time quantitative polymerase chain reaction was performed to comprehensively analyse the expression of all SiWRKY genes in response to dehydration. Results indicated that most SiWRKY genes (over 0.8) were up-regulated by drought stress. In conclusion, genome-wide identification and expression profiling of SiWRKY genes provided a set of candidates for cloning and functional analyses in plants’ response to drought stress.

In vitro rumen methane output (IRMO) of over 200 feed/feed mix samples representing approximately 74 feed types was investigated in a series of completely randomized experiments. The samples comprised dry fodder, grass, tree leaves, cultivated grasses, cereal by-products, cereal grains, oilseed/meals, compound feeds and total mixed rations (TMRs) from the tropical regions. These samples were subjected to three in vitro gas production tests at 39 °C in 100 ml Heberle syringes. The first incubation was conducted with 200 mg dry matter (DM) substrate for 96 h to determine half-time gas production (t 1/2, h) value of each sample. The second and third incubations were carried out simultaneously. The second incubation was done with 200 mg DM substrate until t 1/2 time to determine IRMO and third with 500 mg DM to estimate in vitro dry matter digestibility (IVDMD) of each samples, respectively. The IRMO was expressed as ml/100 mg digestible substrate. Crude protein content (g/kg DM) was lowest in dry fodder samples and highest in oilseed meals, whereas it was similar in local grass and tree leaves. The IVDMD values ranged from 0·48 to 0·87; the lowest digestibility was recorded in tree leaves. The potential gas production (PGP, ml/200 mg DM) ranged from 9·76 to 61·3. The PGP from grasses and compound feeds was similar, whereas it was lowest in tree leaves. The rate constant (mg/h) was maximum in compound feed followed by oilseed meal. The rate constant was similar among other group of feedstuffs. The t 1/2 time ranged from 9·8 to 19·4 h. The highest t 1/2 time was recorded in local grass samples followed by dry fodder and cultivated grasses. However, they were similar among tree leaves, cereal grains, by-products and compound feeds. The methane % in the total gas varied from 9·79 (tree leaves) to 20·2 (local grasses). Among straw, IRMO varied from 3·88 (Zea mays fodder) to 12·0 (Sorghum vulgare) and it was lower in fruit tree leaves than cultivated grasses. Among protein and energy sources, IRMO was higher in cereal by-products as compared with cereal grains, oil meals and compound feed. The IRMO was similar among TMR, irrespective of the composition of the concentrate mixture. Nevertheless, it varied with the amount of concentrate in the TMR. This is the first exhaustive data on IRMO from the tropical region. Because of the substantial amount of dietary gross energy lost in methane, knowledge of the methane output from these feed ingredients will help in formulating low methane emitting diets for ruminants. Incorporation of tropical tree leaves in the diets and feeding TMR are potential strategies to reduce enteric methane emission in ruminants.

On-farm demonstration-trials are a common strategy to introduce new technologies to farmers, while simultaneously evaluating these technologies’ performance under farmer conditions. The current study focuses on conservation agriculture (CA) technology adoption dynamics among a small group of farmers who can be considered increasingly knowledgeable, as they have hosted CA demonstration-trials for at least 7 years. Management and performance of farmers’ fields were compared with the CA demonstration-trials implemented on the same farm, focusing on yield gaps (YGs) between the two and the uptake of CA or some of its principles. Comparisons were made between demonstration-trials and farmers’ fields in three distinct land classification areas: Madziwa Communal Area (est. 1910s), Chavakadzi (est. 1980s) and Hereford (est. 2000s) Resettlement Areas. It was found that closing knowledge gaps on CA did not close YGs and that CA adoption was partial. In the Communal Area, CA principles have barely been taken up, but farmer yields were often as good as on the demonstration-trials. In the Resettlement Areas, farmers did take up reduced tillage (CA principle 1) and practised rotations (CA principle 3), but not residue retention (CA principle 2). Rather than partial CA adoption, lower fertilization rates explained the recorded YGs in the Resettlement Areas. In the three areas, farmers’ interest in CA-based increasing of yields was limited, as circumstances drove them to embark on extensification rather than a land use intensification pathway.

Cowpea genotypes that efficiently utilize phosphorus (P) with high potential for biological nitrogen (N) fixation (BNF) are vital to sustainable cropping systems in West Africa. A total of 175 early maturing cowpea genotypes were evaluated in 2010 and 2011 for P use efficiency (PUE) and BNF with an indigenous rhizobial population at Shika in the Northern Guinea savanna of Nigeria. There were significant genotypic variations for all 11 variables measured. The P utilization index, percentage N derived from the atmosphere and total N fixed ranged between 2·10–4·67, 31·3–61·86% and 11·86–50 kg/ha, respectively. The 175 early maturing cowpea genotypes were divided into five categories using principal component analysis (PCA), whereby total N fixed was associated with N and P uptake and plant biomass yield. Complete linkage cluster analysis revealed a total of three distinctive clusters having remarkable correspondence with the PCA. Some genotypes were identified as potential candidates for further breeding programmes using high PUE genotypes with relatively high capacity for BNF and indigenous rhizobial populations.

Pearl millet (Pennisetum glaucum (L.) R.) could play an important role as a feed source for ruminants in arid and semi-arid zones of the world owing to its high yield and drought tolerance. The current paper assessed the agronomic characteristics, ensilability, intake and digestibility of five Brazilian pearl millet cultivars (IPA Bulk1BF, BRS 1501, CMS-03, CMS-01 and BN-2) in a typical Brazilian northeastern semi-arid climate. Forage was harvested at the dough stage of grain maturity (growth stage 86 according to the BBCH scale) and ensiled under laboratory and farm conditions. Apparent digestibility of the silages was determined using 25 Santa Inês male lambs. The cultivars CMS-01, CMS-03 and BN-2 out-performed the others in terms of dry matter (DM) and digestible DM yield/ha. At DM partitioning among plant tissues, the cultivar IPA Bulk1BF had a greater DM associated with panicles and one of the greatest concentrations of organic matter, lactic acid and in vitro dry matter digestibility among the five cultivars. The cultivar BRS 1501 had greater butyric acid concentration as well as one of the highest pH values. Silage produced from BN-2 not only contained greater acetic acid concentration, but also showed one of the greatest total volatile fatty acid concentrations. There were no differences in feed intake and digestibility of nutrients and fibre fractions across all cultivars. Silage made from BN-2 resulted in greater urinary excretion of nitrogen than those produced from BRS 1501. Under the conditions of the present study, the results obtained for production of DM and digestible dry matter, and the ratio of plant fractions, indicates the possible use of these cultivars for silage production in the Brazilian semi-arid region.

Lignification-associated phenolic acids are widely distributed in graminaceous plant cell walls. Nylon bags containing maize bran, wheat bran, millet husk and rice husk were incubated in the rumens of five Charolais (♂) × Nanyang (♀) crossbred steers for 6, 12, 24, 36, 48 and 72 h. The in situ ruminal disappearance of ester-linked phenolic acids linearly increased in the brans with increasing incubation time, and the disappearance was greater for ester-linked ferulic acid (FAest) than for ester-linked p-coumaric acid (PCAest). The disappearances of FAest and PCAest were positively correlated with disappearances of neutral detergent fibre (NDF), cellulose and hemicellulose. The effective degradabilities of NDF, cellulose and hemicellulose in the brans were markedly greater than the effective degradabilities of these components in the husks, and were negatively correlated with the contents of Lignin (sa), ether-linked ferulic acid, PCAest and ether-linked p-coumaric acid in both the cereal brans and husks. These findings suggested that breeding forage crops with modified phenolic acid contents could represent an alternative strategy to promote further increases in fibre digestibility of cereal residue feeds for ruminant animals.

Lodging can be an important factor in limiting yield and quality of summer foxtail millet [Setaria italica (L.) P. Beauv.]. Although lodging resistance varies among different genotypes, direct selection for lodging resistance is difficult because of its sporadic occurrence in the field and inconsistency between years. A 2-year-field study was conducted with 35 summer foxtail millet cultivars or advanced breeding lines to determine the association between lodging resistance and culm morphology, anatomy and chemical composition. Path analyses indicated that stem-breaking strength had the most important effect on the lodging coefficient. The breaking strength of stem was associated with specific morphological properties of the culm, such as greater culm diameter and most importantly culm wall thickness. Width of sclerenchyma tissue, and the number and sheath width of the large vascular bundles were the major anatomical properties that influenced stem-breaking strength. The cellulose and lignin compositions of the culm had different effects on stem-breaking strength. Cultivars with smaller lodging coefficients contained higher levels of cellulose, but lower levels of lignin than the cultivars that were more prone to lodging. The findings from the present study provide useful information on lodging-associated traits in the culm that can be used as indicators for the improvement of lodging resistance in foxtail millet.

A study was carried out in the rainy seasons of 2008 and 2009 in Niger to investigate the effects of fertilizer micro-dosing on root development, yield and soil nutrient exploitation of pearl millet. Different rates of diammonium phosphate (DAP) were applied to the soil at different depths and it was found that although micro-dosing with DAP increased grain yield over the unfertilized control to a similar level as broadcast DAP, doubling the micro-dosage did not increase it further. Increasing the depth of fertilizer application from 5 to 10 cm resulted in significant increases in root length density, and deep application of fertilizer resulted in higher yields, although the increases were generally not significant. It was postulated that the positive effect of micro-dosing resulted from better exploitation of soil nutrients because of the higher root volume. Levels of nutrients exported from the soil were at least as high in plants receiving micro-dosing as the unfertilized control, and plants receiving micro-dosing exported 5–10 times more phosphorus from the soil than the amount added through fertilization.