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Fonio is an easy crop to grow because it grows well even on poor sandy soils, as well as in areas with low rainfall. The crop can withstand long dry spells during the production season which are becoming a common occurrence in the West African sub-region. In The Gambia, the common name for the crop is 'Findi'. It is commonly grown in fields that were previously cultivated with groundnut. Fonio is one of the oldest cereal crops grown in the country; however, its cultivation has drastically declined to the extent that it is currently considered a minor crop in the country. Fonio is a very fast-growing crop and matures earlier than most cereals. Its ability to withstand dry spells and its high nutritive value makes it an ideal climate-smart crop. For this reason, there is renewed momentum in promoting the crop in the country. Despite these renewed efforts in its promotion, there still exists a huge gap in terms of information on improved production practices that could help uplift the existing low yields. Appropriate agronomic practices that can boost fonio productivity are not well documented at national level. To gather information on the input requirements and utilizations, adaptability and productivity of fonio in The Gambia, experiments were conducted in 2018 and 2019 with the aim of generating important production information that could guide efficient production and enhance productivity. Results obtained showed that fonio responded positively to application of fertilizer. Application of 100 kg [ha.sup.-1] comprising half NRK (15-15-15) and half urea was sufficient to produce financially beneficial yields. Results also indicated that 'Findiba', which is a landrace may not be suitable for cultivation anymore due to its long growth period amidst the short and erratic nature of the rainfall. The Momo and the Momosato varieties which are of shorter durations and high-yielding are more suitable in the existing climatic conditions of the country. Key words: Crop, fonio, fertilizer, variety, production, yield, adaptability, The Gambia, INTRODUCTION Fonio (Digitaria exilis) is one of the oldest native, but neglected, cereal crops of cultural, nutritional and economic importance of West Africa [1]. Fonio seeds are rich in methionine [...]

The integration of organic fertilisers into agricultural practices is one approach to enable more efficient agricultural management systems to decrease adverse environmental impacts of agriculture. In this context, the objective of this research was to determine the impact of long-term crop rotation and organic and mineral fertilisation on soil humus content, humic and fulvic acids, organic matter humification in organic and sustainable agricultural management systems with low (1.90-2.01%) and moderate (2.10-2.40%) initial humus contents. Long-term field experiments with different agricultural management systems started in 1960 at the Lithuanian Research Centre for Agriculture and Forestry and soil humus dynamics experiments were conducted from 2006 to 2017. Results of the long-term use of organic and sustainable agricultural management systems with different crop rotations and fertilisation revealed the positive effect of the applied supplies on soil humus, especially for farmyard manure in combination with green manure. The incorporation of farmyard manure and biomass of white mustard resulted in a lower degree of humification when compared to green manure alone, green manure + mineral N, and farmyard and green manure + mineral N. In the low humus content soil, the degree of humification under all agricultural management systems was significantly improved, on average by 0.9% compared to soil with a moderate humus content. Keywords: green manure, crop rotation, organic and sustainable agriculture, humus, humic and fulvic acids., Introduction One of the most important indicators of soil fertility is the soil organic matter and/or humus content. Under normal conditions, humus is of utmost importance as it supplies most [...]

Bioassays were undertaken in a controlled environment to assess whether the potential for suppression of Rhizoctonia root rot of wheat, in a highly calcareous topsoil, was positively influenced by nutrient (nitrogen (N) or phosphorus (P)) addition and whether any disease suppression response to augmented nutrition was affected by the addition of carbon (C), either as a readily available C source (sucrose) or as wheat stubble. The soil was P deficient, which limited plant growth, populations of putatively beneficial soil microorganisms, and microbial activity and diversity. This ultimately reduced potential for suppression of Rhizoctonia solani AG8. Addition of fertiliser P to the soil increased R. solani AG8 DNA and percent root infection but not the effectiveness of the pathogen. A positive effect of P fertiliser on plant growth partially compensated for the negative effect of increased root infection. Addition of P increased DNA for Microbacterium spp. where labile C had been added and in the presence of plant roots. Stubble addition alone, after 6 weeks of incubation, increased DNA for Pantoea agglomerans, Trichoderma A and Microbacterium spp. although differences in microbial activity and diversity between stubble treatments were only detected after the bioassay had commenced and P was added. Fertiliser P addition to stubble-amended soil resulted in less Rhizoctonia infection compared with that in soil without P or stubble addition. Effectiveness of R. solani AG8 was decreased by 50% with stubble amendment. The application of N alone did not have a marked effect on plant growth or potential for suppression of Rhizoctonia root disease. Agronomic management practices that affect quantity and lability of C input to soil, when combined with strategic P fertiliser decisions, are likely to improve the potential for development of suppression of Rhizoctonia root rot disease in cereal crops on alkaline and highly calcareous soils. Keywords: calcareous, microbial diversity, nitrogen, phosphorus, soil-bome diseases, Rhizoctonia, stubble management, suppression., Introduction A large proportion of cereal production in Australia occurs in semiarid regions on coarse-textured soils that have many edaphic limitations to agricultural productivity (McKenzie et at. 2004). These limitations [...]

The excessive use of fertilisers and frequent and deep tillage are not considered good agricultural practices because they increase production costs and reduce soil fertility. Water extractable organic matter (WEOM) is the fraction of soil organic matter responsible for nutrient transport and bioavailability. The aim of this work was to investigate the effect of a 2-year rotation of faba bean-wheat, cultivated for a decade, and the agricultural practices (conventional vs no tillage, and fertilisation vs no fertilisation) on selected soil parameters and WEOM quality. Results showed that the soil organic carbon (SOC) and the total nitrogen (TN) content increased after the wheat and faba bean, respectively. Plots managed with conventional tillage showed WEOM with higher OC content with respect to no-tillage plots. A higher WEOM OC content was observed also in the fertilised plots. The WEOM of fertilised and faba bean plots was derived from decomposition of native SOC, but the microbial community decomposition was the main origin of WEOM after wheat. Additional keywords: conventional tillage, faba bean, no tillage, WEOM, wheat. Received 4 October 2018, accepted 18 February 2019, published online 15 March 2019, Introduction The rational use of fertilisers and the adoption of minimum or no tillage (NT) are considered good practices for sustainable agriculture because these practices positively influence soil properties and [...]

Inappropriate fertiliser applications have caused a series of environmental problems and threaten the sustainable production of rice in China. The aim of this study was to evaluate the effects of a new approach, Nutrient Expert (NE), a nutrient decision support tool for rice (Oryza sativa L.). Experimental validation was carried out under field conditions from 2013 to 2015 at 211 sites in the main rice-growing regions of China. The results showed that, compared with current farmers' fertiliser practices (FP) and soil testing (ST), the NE approach balanced nutrient application decreased the nitrogen (N) and potassium (K) rates, and increased the phosphorus (P) rate--and improved grain yield, nutrient uptake, and fertiliser use efficiency. The NE treatment produced a 3.5-6.3% higher grain yield, 2.3-14.2% higher N, P, and K uptake in aboveground plant dry matter, and higher agronomic efficiency, apparent recovery efficiency (RE), and partial factor productivity of applied N and K, but not for P. In particular, the RE of the NE approach was greater by 12.2 and 8.4 percentage points for N, 3.7 and 2.9 percentage points for P, and 16.3 and 6.4 percentage points for K, compared with FP and ST respectively. The results obtained from field validation suggested that the NE approach could predict target yields; nutrient uptake of N, P, and K. within specific ranges; and could be used as a tool to make fertilizer recommendation for rice in China. Additional keywords: fertiliser use efficiency, nutrient expert, soil test, yield., Introduction Rice (Oryza sativa L.) is the main staple food crop in China, with a planting area of ~30 million hectares, accounting for 30% of food crop planting areas in [...]

Contemporary African agricultural policy embodies the African Green Revolution's drive towards modernisation and commercialisation. Agroecologists have criticised this movement on ecological, social and political grounds. Northern Ghanaian fertiliser credit schemes provide a good example through which these critiques can be examined in a context where agricultural policy reflects the African Green Revolution's ideals. This study aimed to determine the relationship of such credit schemes to farmers' use of organic amendments, elucidate other factors related to organic amendment use, and comment on the relevance of this modernisation policy and its relationship to agroecology. A first research phase employed semi-structured key informant interviews. Qualitative data from these informed construction of a semi-structured questionnaire that was used in a survey of 205 farmers. Multistage sampling purposively identified five villages and selected farmers within who had joined government and donor-funded fertiliser credit schemes. The use of organic and inorganic amendments was compared to that of peers who had not taken part in such schemes. Quantitative data were used in binomial logistic regression, inferential and descriptive statistics. Qualitative data were content analysed. Credit group membership was associated with higher fertiliser application and yield, but had little influence on the extent of commercialisation. Farmers who applied organic amendments were 40% less likely to belong to a fertiliser credit scheme than not, indicating substitution between organic and inorganic fertilisers. Organic amendments were 40% more likely to be applied to compound farms than outfields and six times more likely to be applied by household heads than other household members. However, household heads also preferentially joined credit groups. This was part of an agroecological soil fertility management strategy. Household heads appreciated the soil moisture retention properties of organic amendments, and applied them to compound farms to reduce risk to their household food supply in a semi-arid environment. They simultaneously accessed fertiliser to enhance this household provisioning strategy. They appreciated the increased yields this achieved, yet complained that the repayment terms of credit schemes were unfair, fertiliser did not enhance yields in dry conditions and fertilisers were supplied late. Farmers' use of credited fertiliser alongside their existing agroecological strategy is helpful to the extent that it raises yields, yet is problematic in that it conflicts with risk-reduction strategies based on organics. There is some potential for modernised and agroecological management paradigms to coexist. For fertiliser credit to play a role in this, schemes must use fairer repayment terms and involve a focus on simultaneous use of organic amendments. Key words: Agroecology, compost, Ghana, fertiliser credit, Soil Fertility Management, maize, INTRODUCTION African agriculture has been commercialised and modernised in the 21st century. This is typified by the African Green Revolution movement, which aims at increasing yields through modern technologies [1]. [...]

Efficiency of use of various phosphate fertilisers is affected by water-insoluble reaction products such as Fe-P, Al-P, and Ca-P in either discrete precipitates or surface-adsorbed forms. A product, maleic-itaconic acid copolymer, has been marketed for increasing efficiency of use of phosphate fertilisers. Field trials have been conducted to evaluate the agronomic effectiveness of this product with no measured positive effects. This absence of positive effects can be explained if fundamental principles of chemistry are considered. The negative logarithm of the equilibrium constant (pK) of CaHP[O.sub.4].2[H.sub.2]O (DCPD) is higher than that of Ca-maleic acid and Ca-itaconic acid complexes. Therefore, the copolymers cannot prevent DCPD formation in calcareous soils. Likewise, because of the pK values of Fe-maleic, Fe-iticonic acid, Al-maleic acid, and Al-itaconic acid are lower than those values for AlP[O.sub.4] x 2[H.sub.2]O, and FeP[O.sub.4] x 2[H.sub.2]O, the copolymer cannot block or prevent formation of AlP[O.sub.4] x 2[H.sub.2]O and FeP[O.sub.4] x 2[H.sub.2]O in acid soils. The results of agronomic greenhouse and field trials can be explained by the considerations of the solubility-product constant or the dissociation constant of cationchelate for various reactions. Therefore, the copolymer marketed has little value for increasing P efficiency from phosphate fertilisers as claimed by the manufacturer. Additional keywords: equilibrium constant, P efficiency, P solubility, soil P-fixing capacity., Introduction Phosphorus (P) is an essential macronutrient for plant growth and application of fertiliser P is an essential input into agriculture to optimise and maintain crop production in most soils [...]

A set of laboratory experiments were conducted to evaluate the physiological quality of Sorghum bicolor (L.) Moench seeds subjected to different field cultural management practices. The main aim of this study was to contribute towards improved production of Sorghum bicolor (L.) Moench through better understanding of the crop's agronomy. The experimental design was a three factorial split-split block design in the rain fed Sorghum bicolor (L.) Moench producing areas of Bomet County of Kenya. Treatments within the block were randomized. There were three factors which included variety at two levels (improved and local varieties); fertilizer application at two levels (with and without fertilizer); and seed selection at three levels (continuous, from booting stage and at harvest). Percentages of crop emergence and days to 50% physiological maturity were determined. The following seed quality tests were carried out: 1000-seed weight, standard germination, mean germination time and electrical conductivity. The improved variety had a field emergence of 100% while that of the local variety ranged from 60-97%. In regard to field emergence and maturity, there were significance differences (P [less than or equal to] 0.001) between plots with fertilizer and those without regardless of the variety. Those plots with fertilizer outperformed those without. Germination and vigour tests indicated that seed selection time did not influence seed vigour, viability and yield (P [less than or equal to] 0.05). However, there were significant differences (P [less than or equal to] 0.001) between the improved variety (E1291) and local (Ochuti) variety. In relation to this, variety E1291 showed better seed vigour, viability and yield as compared to Ochuti. Similarly, there were significant differences (P [less than or equal to] 0.001) between plots to which fertilizer was applied and those without. Fertilizer application led to an increase in seed yield, seed weight, seed vigour and viability. It was therefore concluded that (i) E1291 was more adapted to the study area as compared to Ochuti and hence should be adopted by farmers; (ii) farmers should apply optimal phosphate and nitrogenous fertilizers to their soils so as to increase the quality and yield of their seed; and (iii) farmers could continue selecting their seed using their indigenous knowledge. Key words: Seed, Sorghum bicolor, viability, vigour, yield, INTRODUCTION Sorghum [Sorghum bicolor (L.) Moench] is an important staple cereal crop that contributes immensely to domestic food supply and rural household income. Generally, total Sorghum [Sorghum bicolor (L.) Moench] [...]

Inefficient extraction of litter-derived N and its loss to the immediate environment is a concern when poultry litter is used as a fertilizer. This research determined the magnitude of N extraction by cotton (Gossypium hirsutum L.) fertilized with broiler litter with or without supplemental inorganic N. Extraction of N by cotton fertilized with litter rates of 2.2, 4.5, and 6.7 Mg [ha.sup.-1] in combination with 0, 34, or 67 kg [ha.sup.-1] N as urea-ammonium nitrate (UAN) was determined on two farms, one at Cruger and another at Coffeeville, MS, in 2002 to 2004. The treatment that received 4.5 Mg [ha.sup.-1] litter plus 67 kg [ha.sup.-1] UAN-N was among the treatments that had the largest N extraction with an average across years of 233 kg N [ha.sup.-1] total extraction at Cruger and 183 kg N [ha.sup.-1] at Coffeeville. These extractions were more or onlY slightly less than the total applied N. An average of 56% of extracted N at Cruger and 62% at Coffeeville was partitioned to seed and lint, which represents an amount that would be removed from the field. The remainder is bound in plant parts with little or no risk of becoming released to the immediate environment until the plant parts decompose. These results demonstrate cotton is efficient at extracting N supplied by as much litter as 6.7 Mg [ha.sup.-1] when supplemented with inorganic N. The risk of N detrimentally affecting the immediate environment when cotton is fertilized with litter plus inorganic N is no greater than when fertilized with 100% inorganic N fertilizers.

Phosphorus and K fertilization increases alfalfa (Medicago sativa L.) yield and stand persistence, but the changes in yield components as affected by P and K fertility level are not known. Our hypothesis is that P and [or) K fertilization will increase one or more alfalfa yield components, and those component responses may change with stand age. The objectives of this field study were to determine the impact of P and K fertilization on alfalfa forage yield and yield components during the initial 3 yr after establishment. Treatments were the factorial combinations of four P rates (0, 25, 50, and 75 kg P [ha.sup.-1]) and five K rates (0, 100, 200, 300, and 400 kg K [ha.sup.-1]) arranged in a randomized complete block design with four replications. Forage harvests occurred four times annually, and yield, mass [shoot.sup.-1], and shoots [area.sup.-1] were determined. Plant populations were determined in early December and late May each year. Incremental additions of in early December and late May each year. Incremental additions of P and K increased alfalfa yield in each year. Potassium fertilization did not influence plant population, while robust P-responsive alfalfa plants apparently crowded out smaller, less vigorous plants thus decreasing plants [m.sup.-2]. Stand assessments based on shoot counts, or aboveground plant counts may not accurately indicate alfalfa yield potential. Shoots [plant.sup.-1] was not affected by application of either nutrient, while shoots [m.sup.-2] generally declined with increased P and K fertilization. Improved forage yield of P- and K-fertilized plots was consistently associated with greater mass [shoot.sup.-1]. Because fertilizer-responsiveness is closely associated with greater mass [shoot.sup.-1], cultivars possessing this trait may be relatively more productive under well-fertilized conditions., THE IMPACT OF MINERAL nutrition on alfalfa agronomic performance has been documented by several investigators (Nelson and MacGregor, 1957; Markus and Battle, 1965; Collins and Duke, 1981; Suzuki, 1991). Phosphorus [...]

In a world of limited resources and inexorable pressure to produce food for burgeoning populations, innovative approaches are needed to exploit these resources in a sustainable manner. Phosphorous (P) fertilizers are used extensively throughout the world for commercial crop production, and are a major factor in global food security. Yet, in developing countries, limited or no P fertilizer is used, often because of cost and infrastructure constraints, and this is therefore an impediment to sustainable production. The challenge facing soil scientists involved with soil and fertilizer P research is to produce adequate crops on inadequately fertilized soils in poorer countries and, at the same time, improve the efficiency of P use where excessive amounts are used, thus avoiding negative environmental impacts. Soil-plant fungi, especially arbuscular mycorrhizae (AM), may have a role in solving both horns of the P-use dilemma, since such associations have been shown to vary with plant species, and indeed genotypes within species, and to enhance crop utilization and uptake of P from soils low in soluble or available P. Therefore, as corn is an important feed and food crop in the Mediterranean coastal area of Turkey, we conducted two greenhouse studies to assess the P efficiency of a range of widely grown local corn genotypes and to establish the possible role of mycorrhizae in determining differences in observed P efficiency. The nine genotypes were grown with low to high P fertilizer rates (25-200 mg [kg.sup.-1]) and assessed for P efficiency, based on visual observations, dry matter yield, and tissue P concentration. Two efficient and two inefficient genotypes were then grown with and without P fertilizer and added mycorrhizae. The experimental bulk soil had natural mycorrhizal colonization. The genotypes XL 72AA, DK 626 and LG 60, LG 2777 responded differently to both P and mycorrhizal infection. The efficient genotypes were more dependent on added P (two-fold yield increase) and mycorrhizae than the inefficient ones. Thus, while mycorrhizal colonization is not a substitute for fertilizer use, it is complementary to it. While difficulties still remain for AM inoculation of crops in the field, more attention to mycorrhizae should be given by plant breeders in the process of crop improvement. Key words: genotype assessment, P efficiency, mycorrhizal colonization, mycorrhizal dependency, corn

Managed turfgrass acreage in the southeastern USA is steadily increasing. There is public concern that fertilization of turfgrass systems, particularly additions of N on golf courses, might be adversely affecting groundwater quality due to nitrate leaching. This study was conducted to measure soil nitrate levels in situ under continuously managed bermudagrass (Cynodon spp.) and to evaluate influences from fertilization and mineralization. Two experimental sites were established on 50- and 75-yr-old golf course fairways in the Neuse and Cape Fear River basins in eastern North Carolina. Soil sampling was done seasonally. Results indicate that nitrate-N levels were consistently low (1 to 4 mg [kg.sup.-1] soil) and similar to adjacent natural areas throughout the 120-cm sampling depths during the 2-yr experiment at both sites. Levels were relatively uniform with depth and across several landscape positions. The soil nitrate levels under fertilized fairways were similar to those in adjacent nonfertilized natural areas, indicating minimal influence from turf management practices. From laboratory mineralization studies and soil temperature data, it was estimated that 60 to 154 kg N [ha.sup.-1] would be released from organic N pools during the bermudagrass growing season (May to October). Because of similar temperature responses, it appeared that N release from mineralization would be synchronized with bermudagrass growth. Substantial bermudagrass growth in nonfertilized plots provided direct evidence that mineralization was a significant contributor to turf nutrition. There was no evidence that N fertilization or the ecology of the bermudagrass system posed inherent risks to water quality and the environment., MANAGED TURFGRASS systems are increasing in acreage throughout the southeastern USA. The increases are linked to population growth and the associated home lawns and recreational areas. Fertilizers are necessary to [...]

The implementation of tillage, seeding, and fertilizer application technologies for rainfed cereal production with a winter precipitation pattern requires integration of soil and water conservation systems into the total production system. The technologies can improve residue management, stand establishment and crop fertilization in the Pacific Northwest region. This improves soil and and water conservation, but can cause uncontrolled pest growth resulting in lesser yield. These implements also affect plant diseases, insects, weeds, environmental degradation, crop yield and quality.

Worldwide fertilizer consumption has increased overall from 1961-1962 to $50 billion in 1989-1990. Developing countries increased their use the most, to boost agricultural production. Developed countries' use of fertilizers stagnated in the early '80s due to environmental concerns. The rate of use in Eastern Europe and former Soviet Union countries has declined since the use of subsidies and the control of prices has changed.