Effects of manure and fertilizer on grain yield, soil carbon and phosphorus in a 13-year field trial in semi-arid Kenya

Long-term indicators of soil fertility were assessed by measuring grain yield, soil organic carbon (SOC) and soil Olsen phosphorous for a P-deficient soil. In one set of treatments, goat manure was applied annually for 13 years at 0, 5 and 10 t ha(-1), and intercrops of sorghum/cowpea, millet/green gram and maize/pigeonpea were grown. Yield depended on rainfall and trends with time were not identifiable. Manure caused an upward trend in SOC, but 10 t ha(-1) manure did not give significantly more SOC than 5 t ha(-1). Only 10 t ha(-1) manure increased Olsen P. Measurements of both SOC and Olsen P are recommended. In another set of treatments, manure was applied for four years; the residual effect lasted another seven to eight years when assessed by yield, SOC and Olsen P Treatment with mineral fertilizers provided the same rates of N and P as 5 t hat manure and yields from manure and fertilizer were similar. Fertilizer increased Olsen P but not SOC. Management systems with occasional manure application and intermediate fertilizer applications should be assessed. Inputs and offtakes of C, N and P were measured for three years. Approximately 16, 25 and 11% of C, N and P respectively were stabilized into soil organic matter from 5 t ha(-1) a(-1) manure. The majority of organic P was fixed as soil inorganic P.

Effects of cultural system (organic and conventional) on growth, photosynthesis and yield components of sweet corn (zea mays L.) under semi-arid environment

Organic sweet maize consists of a new industrial crop product. Field experiment was conducted to determine the effects of cultural systems on growth, photosynthesis and yield components of sweet maize crop (Zea mays L. F-1 hybrid 'Midas'). A randomized complete block design was employed with four replicates per treatment (organic fertilization: cow manure (5, 10 and 20 t ha(-1)), poultry manure (5, 10 and 20 t ha(-1)) and barley mulch (5, 10 and 20 t ha(-1)), synthetic fertilizer (240 kg N ha(-1)): 21-0-0 and control). The lowest dry weight, height and leaf area index and sod organic matter were measured in the control treatment. Organic matter content was proportionate to the amount of manure applied. The control plots had the lowest yield (1593 kg ha(-1)) and the double rate cow manure plots the had,greatest one. (6104 kg ha(-1)). High correlation between sweet corn yield and organic matter was registered. Moreover, the lowest values of 1000-grain weight were obtained with control plot. The fertilizer plot gave values which were similar to the full rate cow manure treatment. The photosynthetic race of the untreated control was significantly lower than that of the other treatments. The phorosynthetic rate increased as poultry manure and barley mulch ram decreased and as cow manure increased. Furthermore the untreated control had the lowest stomatal conductance and chlorophyll content. Our results indicated that sweet corn growth and yield in the organic plots was significantly higher than those in the conventional plots.

The effects of organic and conventional fertilizers on cereal aphids and their natural enemies

Aphids are important pests of spring cereals and their abundance and the impact of their natural enemies may be influenced by fertilizer regime.2We conducted a 2-year field study investigating the effects of organic slow-release and conventional fertilizers on cereal aphids, hymenopteran parasitoids and syrphid predators and considered how the effects of fertilizers on barley morphology and colour might influence these species.3Barley yield was greater in conventionally fertilized pots. Barley morphology was also affected by treatment: vegetative growth was greater under conventional treatments. Barley receiving organic fertilizers or no fertilizer was visually more attractive to aphids compared with plants receiving conventional fertilizers.4Aphids were more abundant in conventionally fertilized barley but the reason for this increased abundance was species specific. Metopolophium dirhodum was responding to fertilizer effects on plant morphology, whereas Rhopalosiphum padi was sensitive to the temporal availability of nutrients.5Syrphid eggs were more numerous in conventionally fertilized pots, whereas the response of parasitoids appeared to be dependent on the abundance of aphids, although the number of parasitoid mummies was low in both years.6This research shows that the fertilizer treatment used can affect numerous characteristics of plant growth and colour, which can then influence higher trophic levels. This knowledge might be used to make more informed fertilizer application choices.

Effects of organic and conventional fertiliser treatments on host selection by the aphid parasitoid Diaeretiella rapae

The type and quantity of fertilizer supplied to a crop will differ between organic and conventional farming practices. Altering the type of fertilizer a plant is provided with can influence a plant’s foliar nitrogen levels, as well as the composition and concentration of defence compounds, such as glucosinolates. Many natural enemies of insect herbivores can respond to headspace volatiles emitted by the herbivores’ host plant in response to herbivory. We propose that manipulating fertilizer type may also influence the headspace volatile profiles of plants, and as a result, the tritrophic interactions that occur between plants, their insect pests and those pests’ natural enemies. Here, we investigate a tritrophic system consisting of cabbage plants, Brassica oleracea, a parasitoid, Diaeretiella rapae, and one of its hosts, the specialist cabbage aphid Brevicoryne brassicae. Brassica oleracea plants were provided with either no additional fertilization or one of three types of fertilizer: Nitram (ammonium nitrate), John Innes base or organic chicken manure. We investigated whether these changes would alter the rate of parasitism of aphids on those plants and whether any differences in parasitism could be explained by differences in attractivity of the plants to D. rapae or attack rate of aphids by D. rapae. In free-choice experiments, there were significant differences in the percentage of B. brassicae parasitized by D. rapae between B. oleracea plants grown in different fertilizer treatments. In a series of dual-choice Y-tube olfactometry experiments, D. rapae females discriminated between B. brassicae-infested and undamaged plants, but parasitoids did not discriminate between similarly infested plants grown in different fertilizer treatments. Correspondingly, in attack rate experiments, there were no differences in the rate that D. rapae attacked B. brassicae on B. oleracea plants grown in different fertilizer treatments. These findings are of direct relevance to sustainable and conventional farming practices.

Influence of organic-mineral fertilization of an oxisol on soil chemical properties and Bracharia brizantha production

A utilização de fertilizante organomineral da indústria produtora dos aminoácidos lisina e treonina pode melhorar a fertilidade de solos tropicais. O presente trabalho teve como objetivo avaliar a influência de diferentes dosagens do fertilizante organomineral denominado Ajifer L-14 nos atributos químicos e no aumento de produção de forragem de um Latossolo Vermelho do noroeste paulista. O delineamento utilizado foi em blocos casualizados, com sete tratamentos e quatro repetições. Os tratamentos foram: T1- testemunha (sem aplicação de Ajifer L-14); T2- testemunha com vegetação natural; T3- adubação mineral de acordo com a necessidade da cultura e a análise do solo (usando 1,35 kg de ureia, 2,20 kg de superfosfato simples e 0,51 kg de KCl por parcela, o que corresponde a 60 kg de N, 40 kg de P2O5 e 30 kg ha-1 de K2O, respectivamente); T4- adubação com Ajifer L-14 de acordo com a recomendação da análise química do solo (40 L parcela-1, o que corresponde a 60 kg ha-1 N); T5- adubação com Ajifer L-14 em dosagem 50 % acima da recomendação (60 L parcela-1, o que corresponde a 90 kg ha-1 N; T6- adubação com Ajifer L-14 em dosagem 50 % abaixo da recomendação (20 L parcela-1, o que corresponde a 30 kg ha-1 N); T7- adubação com Ajifer L-14 em dosagem 25 % acima da recomendação (50 L parcela-1, o que corresponde a 75 kg ha-1 N); e T8- adubação com Ajifer L-14 em dosagem 25 % abaixo da recomendação (30 L parcela-1, o que corresponde a 45 kg ha-1 N). Nas profundidades de 0,0-0,1 e 0,1-0,2 m, avaliaram-se os seguintes atributos químicos do solo:, teor de matéria orgânica (MO), pH, K+, Ca2+, Mg2+, capacidade de troca catiônica (CTC), acidez potencial e saturação por bases. A aplicação do fertilizante organomineral não influenciou os atributos químicos do solo. Na análise de regressão, houve relação polinomial entre as doses de aplicação do fertilizante organomineral e a produção de massa seca e proteína bruta de Bracharia brizantha.

Microbial populations and activities in sewage sludge and phosphate fertilizer-amended soil

A greenhouse study was conducted to determine the number of microbial populations and activities in sewage sludge and phosphate fertilizer-amended dark red latosoil for cultivation of tomato plants. Sewage sludge was applied at doses of 0, 10, 20, 40, 80 and 160 t ha(-1), and phosphate (P2O5) at doses of 0, 100, 200, 400 and 800 kg ha(-1). The bacterial populations increased as a function of sewage sludge and phosphate application. Fungal populations were not affected by the application of phosphate alone but were increased by the application of sewage sludge. Phosphate doses higher than 100-200 kg ha(-1) in combination with sewage sludge inhibited both bacterial and fungal growth. The responses determined by microbial counts were reflected in the microbial biomass values, with a more significant effect of sewage sludge than of phosphate or of a combination of both. These results confirm the need for a carbon and energy source (represented here by sewage sludge) for microbial growth in a soil poor in organic matter. Dehydrogenase and urease activities reflected the results of the microbial populations due to the effect of sewage sludge and phosphate, but no satisfactory result was obtained for phosphatase. Urease activity was expressed by a linear regression equation as the result of the effect of sewage sludge, and by a quadratic regression equation as the result of the effect of phosphate. All parameters investigated showed a significant correlation with bacterial counts but not with fungal counts, indicating a greater effect of sewage sludge and phosphate on bacteria than on fungi.

Influence of fertilizer on coumarin content and biomass production in Mikania glomerata sprengel

Mikania glomerata Sprengel leaf extracts have been used in cough syrup formulations due to the presence of active coumarin derivatives. Yields of such natural compounds in cultivated plants can be affected by several nutritional factors. To determine the effect of fertilization on biomass productivity, organ proportion and coumarin content, Mikania glomerata plants were submitted during one year to treatments with organic (humus or manure) and inorganic (different levels of nitrogen) fertilizers. Coumarin concentration was raised by organic fertilization, inorganic nutrients induced increased phytomass (stem and leaf) yield, however no fertilized plants showed enhanced leaf production.

Economic evaluation of nile tilapia juvenile production, feed with commercial ration and with primary production come from organic and inorganic fertilization

Study objective was to evaluate economically a Nile tilapia juvenile production, employing different feeding techniques. Tilapia fingerlings of 8g were stocked at 5 fish m-2 stocking in 50 and 150 m2 ponds, during 75 days. Treatments were: inorganic fertilization (P205 and N); organic fertilization (poultry manure) and commercial ration (32% CP). Water quality results were considered adequate for fish rearing. In juvenile production there were significant differences among treatments for individual final weight, medians were: for inorganic fertilization 12.92g (13.35g in 50 m2 and 12.49g in 150 m2); for organic fertilization 30.55g (33.69g in 50 m2 and 27.40g in 150 m2) and for commercial ration 51.23g (52.90g in 50 m2 and 50.15g in 150 m2). Survival rate ranged from 63 to 71%, with no statistic difference. Commercial ration was effective to bigger juvenile production, with a better market value. Costs considered in economic analyses were tilapia fingerlings, fertilizer, ration, labor and installation depreciation. Obtained information showed that juvenile production in 50 m2 ponds is not viable economically and, in 150 m2, production is viable only when commercial ration is used.

Soil phosphorus availability and soybean response to phosphorus starter fertilizer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

SIMULATION OF USE AND MANAGEMENT EFFECTS ON THE SOIL ORGANIC MATTER POOLS OF THE ATLANTIC FOREST BIOME, BRAZIL

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Available nitrogen and responses to nitrogen fertilizer in brazilian eucalypt plantations on soils of contrasting texture

Eucalyptus plantations have seldom responded to N fertilization in tropical and subtropical regions of Brazil. This implies that rates of N mineralization have been adequate to supply tree needs. However, subsequent crop rotations with low N fertilization may result in declining concentrations of organic and potentially mineralizable N (N-0), and consequent loss of wood productivity. This study investigated (a) in situ N mineralization and N-0 in soils of eucalypt plantations in Sao Paulo state, Brazil; (b) tree growth responses to N fertilizer applied 6-18 months after planting; and (c) the relationships between N-0,N- other soil attributes and tree growth. We established eleven N fertilizer trials (maximum 240 kg ha(-1) of N) in E. grandis and E. grandis x urophylla plantations. The soil types at most sites were Oxisols and Quartzipsamments, with a range of organic matter (18 to 55 g kg(-1)) and clay contents (8% to 67%) in the 0-20 cm layer. Concentrations of N-0 were measured using anaerobic incubation on soil samples collected every three months (different seasons). The samples collected in spring and summer had N-0 140-400 kg ha(-1) (10%-19% total soil N), which were best correlated with soil texture and organic matter content. Rates of in situ net N mineralization (0-20 cm) ranged from 100 to 200 kg ha(-1) year(-1) and were not correlated with clay, total N, or N-0. These high N mineralization rates resulted in a low response to N fertilizer application during the early ages of stand growth, which were highest on sandy soils. At the end of the crop rotation, the response to N fertilizer was negligible and non-significant at all sites.

Soil phosphorus dynamics as affected by Congo grass and P fertilizer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PHYSICO-CHEMICAL EVALUATION OF AN EFFLUENT TREATED IN ANAEROBIC BIODIGESTER REGARDING ITS EFFICIENCE AND APPLICATION AS FERTILIZER

PHYSICO-CHEMICAL EVALUATION OF AN EFFLUENT TREATED IN ANAEROBIC BIODIGESTER REGARDING ITS EFFICIENCE AND APPLICATION AS FERTILIZER. The use of biodigester for basic and environmental sanitation has large demand in Brazil. A biodigester was built to treat conjunctly the human and pig feces and urine, regarding to its future application in rural small towns. The results show that the biodigester can reduce 90% of COD and BOD and, up to 99.99% of thermotolerant coliforms. The treated effluent has variable quantities of macro- and micro-nutrients; and organic matter. However, the concentration variability of the nutrients makes difficult a dosed application into soil. The soluble salts (mainly as Na+ form) make necessary a controlled use to avoid environmental degradation.

Nitrogen Fertilizer Form and Associated Nitrate Leaching from Cool-Season Lawn Turf

Various N fertilizer sources are available for lawn turf. Few field studies, however, have determined the losses of nitrate (NO3-N) from lawns receiving different formulations of N fertilizers. The objectives of this study were to determine the differences in NO3-N leaching losses among various N fertilizer sources and to ascertain when losses were most likely to occur. The field experiment was set out in a completely random design on a turf typical of the lawns in southern New England. Treatments consisted of four fertilizer sources with fast- and slow-release N formulations: (i) ammonium nitrate (AN), (ii) polymer-coated sulfur-coated urea (PCSCU), (iii) organic product, and (iv) a nonfertilized control. The experiment was conducted across three years and fertilized to supply a total of 147 kg N ha-1 yr-1. Percolate was collected with zero-tension lysimeters. Flow-weighted NO3-N concentrations were 4.6, 0.57, 0.31, and 0.18 mg L-1 for AN, PCSCU, organic, and the control, respectively. After correcting for control losses, average annual NO3-N leaching losses as a percentage of N applied were 16.8% for AN, 1.7% for PCSCU, and 0.6% for organic. Results indicate that NO3-N leaching losses from lawn turf in southern New England occur primarily during the late fall through the early spring. To reduce the threat of NO3-N leaching losses, lawn turf fertilizers should be formulated with a larger percentage of slow-release N than soluble N.

Efficiency and environmental indexes to evaluate the sustainability of mineral and organic fertilization in an irrigated melon crop

Melon is traditionally cultivated in fertigated farmlands in the center of Spain with high inputs of water and N fertilizer. Excess N can have a negative impact, from the economic point of view, since it can diminish the production and quality of the fruit, from the environmental point of view, since it is a very mobile element in the soil and can contaminate groundwater. From health point of view, nitrate can be accumulated in fruit pulp, and, in addition, groundwater is the fundamental supply source of human populations. Best management practices are particularly necessary in this region as many zones have been declared vulnerable to NO3- pollution (Directive 91/676/CEE) During successive years, a melon crop (Cucumis melo L.) was grown under field conditions applying mineral and organic fertilizers under drip irrigation. Different doses of ammonium nitrate were used as well as compost derived from the wine-distillery industry which is relevant in this area. The present study reviews the most common N efficiency indexes under the different management options with a view to maximizing yield and minimizing N loss.