Substitution Of Chemical Fertilizer Research Articles

Supplementing chemical fertilizer with an organic component increases soil biological function and quality

The aim of this study was to investigate the impacts of organic-supplementation of a chemical fertilizer for improving soil biological activity, particularly towards disease suppression, in a drip-irrigated cotton system. Over a two-year field-based trial, our study characterized effects of partial substitution of chemical fertilizer with two types and amounts of organic components on the size, activity, carbon utilization potential, and culturable groups of pathogenic and antagonistic microbiota. The total microbial community size increased with application of chemical fertilizer (P<0.05), and more so when chemical fertilizer was supplemented with organic amendments (P<0.05). Alteration of microbial biomass carbon to nitrogen ratio, and the ratio of culturable bacteria and fungi, indicated that increases in the microbial community were underpinned by changes in bacteria. Enzymatic activity was greater in soils receiving fertilizer with organic supplement (P<0.05). Multivariate analysis indicated that there was no influence of fertilizer treatments on carbon utilization profiles (CUPs; P>0.05), but a strong year-effect was evident (P<0.05). The population size of Verticillium dahliae and Fusarium oxysporum decreased with organic amendments (P<0.05), whilst antagonistic Trichoderma spp. and Bacillus spp. were inversely correlated to the pathogen populations. Overall, the results of this exploratory study support partial substitution of inorganic fertilizer with organic manure or bio-organic fertilizer to promote suppression of cotton root diseases. Associated benefits on soil biological quality will further increase the sustainability of this agroecosystem.

Organic Manures and Crop Residues as Fertilizer Substitutes: Impact on Nitrous Oxide Emission, Plant Growth and Grain Yield in Pre-Monsoon Rice Cropping System

It has been previously argued that application of organic residues added in soils has a great impact on soil quality, grain productivity as well as greenhouse gas emissions. Substitution of chemical fertilizers has become a common practice in agricultural systems which consequently affect the greenhouse gas emissions from agricultural fields. To observe the effects of organic manures and crop residues amendments, five fertilizer treatments including conventional inorganic nitrogen fertilizer—NPK, cow manure, rice straw, poultry manure and sugarcane bagasse were applied in the field for two consecutive pre-monsoon rice seasons. Addition of rice straw, poultry manure and sugarcane bagasse decreased the cumulative N2O emissions by 14% and 31%, and by 1% and 7% and 5% and 3% in 2012 and 2013 respectively when compared with conventional fertilizer treatment (NPK) in both the seasons. Yield differences were not significant (p > 0.005) amongst the treatments, however, a slight increase was observed due to rice straw amendment over control. Soil organic carbon decreased by 11% - 17% under the application of organic residues which might have contributed to lower N2O emissions from the plots. Results of carbon equivalent emission (CEE) and carbon efficiency ratio (CER) indicated that incorporation of rice straw during pre-monsoon rice season had the potential to reduce the N2O emissions and yield scaled emissions of rice production at lower level than the conventional farmers’ practice of using chemical fertilizers (NPK).

THE INTERREG-DEVAG PROJECT: A REGIONAL NETWORK FOR THE DEVELOPMENT OF AGROECOLOGICAL CROPPING SYSTEMS FOR HORTICULTURAL CROPS IN THE CARIBBEAN

In our Caribbean islands, increasing local food production and reducing the negative impacts of agricultural practices are major concerns, especially in view of the most recent food crisis and the rising costs of imported food products and agricultural inputs. In this context, horticultural crops are the main target of the social demand to get access to safe, healthy and environmentally friendly products. Furthermore, horticultural products are an important source of income for small farmers. But currently these crops are still requiring highly intensive chemical input application (fertilizers, pesticides) due to strong biotic constraints (bacteria, viruses, insects...) amplified by abiotic conditions (heat, humidity). It has become necessary to consider a radical change in production methods to move towards environmentally friendly systems and offering healthy products to producers and consumers, while valorizing biological resources already present in these fragile ecosystems though rich in biodiversity. The objectives of the DEVAG project are (i) to develop scientific databases to accelerate the development of agroecological and organic horticultural productions and (ii) to create a regional network dedicated to the development of agroecology for fruits and vegetables in the Caribbean. To do so, research activities focus on the development of agroecological methods to manage insects, diseases and weeds. These pests represent the main cause of loss of productivity and increase of pesticides use. Nevertheless, in order to build integrated cropping systems adoptable in our environments, research also encompass: (i) substitution of chemical fertilizers with local organic resources, (ii) selection of cultivars adapted to low-input systems, (iii) crop-livestock integration and (iv) characterization of socio-economic determinants of technical innovations. These research activities are conducted in permanent connection with farmers and agricultural development agents who will benefit directly by participating in field experiments and technical field schools. (Resume d'auteur)

Fertilizer inaccessibility, rural livelihood and sustainable agriculture in Kaduna State: a participatory appraisal

Inaccessibility of chemical fertilizer results in low level of productivity among farmers, Apart from low productivity it has other impacts on rural livelihood and the environmental dynamics, which have not been thoroughly investigated. Inorganic fertilizers have become a major source of soil nutrient improvement for many farmers but its high cost usually makes it inaccessible to many farmers. The main purpose of the study is to analyse the socio-economic inaccessibility of chemical fertilizer and itsconsequences on sustainable rural and environment development. A participatory appraisal methodology was adopted. The analysis shows that inaccessibility to chemical fertilizer has negative impact on rural livelihood by causing low yield. However, it has a positive effect by inducing the adoption of organic fertilizer, which is deemed environment-friendly agriculture. The conclusion is that although the environmentfriendly, organic fertilizer-supported agriculture has taken root, it still faces enormous challenges when compared to chemical fertilizers. The study recommends adopting participatory approach to educate, and enlighten farmers as well as to evaluate agricultural and livelihood system of farmers; motivation of farmers who adopt environment-friendly practices; and a gradual substitution of chemical fertilizer with organic nutrient for sustainable agriculture among others.

PHYSICAL METHODS IN AGRO-FOOD CHAIN

Chemical additives (fertilizers and plant protection preparations) are largely used for improving the production yield of food produce. Their application often causes the contamination of raw materials for food production, which can be dangerous for the health of consumers. Alternative methods are developed and implemented to improve and ensure the safety of on-farm production. The substitution of chemical fertilizers and soil additives with alternative treatment methods, such as irradiation, ultrasound and the use of electromagnetic energy are discussed. Successful application of physical methods in different stages of food-preparation is recommended.

The recent trend of agricultural nitrogen flow in Japan and improvement plans

Nitrogen (N) flows associated with agricultural practices and environmental N risk, which is an index of environmental impact, in Japan from 1980 to 1997 were estimated, and the effect of improvement plans for reducing environmental N risk was simulated for two important prefectures. Recent trends have shown that the input of chemical fertilizer and manure is lower compared to crop production, which is also lower. Environmental N risk peaked in 1985 then became lower, and its content changed. Residual N on farmland, defined as N inputs onto farmland (chemical fertilizer, etc.) minus N outputs from farmland (crop uptake, etc.), peaked in 1985, then decreased, although non-utilized livestock excreta increased during the period. To simulate reduction of the environmental N risk, two prefectures that had high applications of chemical fertilizer and high livestock excreta production were selected. Simulated improvement plans were based on the results of past studies, such as low inputs of chemical fertilizer in crop production, substitution of chemical fertilizer by livestock excreta and/or active use of livestock excreta in forage production. Incorporation of these methods was successful in reducing environmental risk in those prefectures, although prefectures that had a large amount of livestock excreta could not find any effective improvement plan, due to lack of appropriate local land use.

Quantitative evaluation of environmental risk associated with nitrogen flow in agricultural production and mitigation plan for 2 typical prefectures in Japan

Nitrogen (N) flow and environmental risk in Japanese agricultural production were estimated for each prefecture in 1997 using a modified nutrient balance calculation system. N flows associated with agricultural production varied widely among the prefectures. The amount of excess N that remained on farmland (residual N), which is a source of environmental risk, also varied widely and was strongly affected by the level of inputs of chemical fertilizer and manure. The prefectures were grouped into 3 categories in relation to environmental risk. 1) Prefectures which had a lower environmental risk than the Japanese average. 2) Prefectures which had a higher environmental risk than the average due to high application of chemical fertilizer, and 3) due to the high production of livestock excreta. Two typical prefectures were selected to implement mitigation plans. Prefecture A belonged to category 2) and had the highest chemical fertilizer input in Japan. Therefore, it was considered that by decreasing the input of chemical fertilizer could be effectively reduced environmental risk. The mitigation plan was drafted to reduce the environmental risk to 69% of the present level. Prefecture B belonged to category 3), and was characterized by a high livestock excreta production of which 47% was not used as manure in the prefecture. By substitution of chemical fertilizer with manure for forage crops and more effective use of manure in paddy fields, it was estimated that the environmental risk in Prefecture B could be reduced to 77% of the present level.

Rice-wheat cropping system: assessment of sustainability under green manuring and chemical fertilizer inputs

Rice-wheat rotations are the most important cropping system of the Indo-Gangetic plains. We measured the long-term sustainability of the system for green manuring and chemical fertilizer input practices utilising the trends in grain yield, partial factor productivity (PFP), agronomic efficiency, benefit : cost ratio, soil organic carbon content (OC) and sustainable yield index (SYI). The data of a long-term experiment conducted at six locations in the Indo-Gangetic plain region of India revealed that grain yield and PFP of both rice and wheat declined under control (no fertilizer, no green manure) and sub-optimal fertilizer inputs (50 or 75% recommended fertilizer NPK) at all locations. Complete dose of fertilizer NPK (100% recommended) increased grain yields as well as PFP in rice but did not prevent decline in these parameters in wheat. Partial substitution of chemical fertilizer with Sesbania green manure, however, brought further improvement in yield and PFP in rice and the residual effect of green manure reversed the declining trend in wheat. The SYI and agronomic efficiency of fertilizers were also greater in plots receiving 100% fertilizer NPK or green manuring along with 50 or 75% recommended NPK. Benefit : cost ratio of fertilizer inputs and green manuring practices increased in both crops and for all treatments, indicating that the benefit accruing from fertilizer improved with time. At locations with high initial OC, a depletion of OC was noticed whereas OC increased at locations with low initial OC, with OC stabilizing between 0.60 and 0.65%. Trends in grain yield, PFP and agronomic efficiency of fertilizer appear promising tools to measure sustainability of fertilizer management practices.

Nitrogen uptake response of crops to organic nitrogen

Abstract Sustainability of agriculture became a major issue of global concern during this decade. Agronomic practices aimed at reducing the dependence on inputs such as chemical fertilizers can contribute to sustainability. Nitrogen (N) is the most limiting and commonly applied nutrient for crop production. The development of nutrient-responsive cultivars especially during the past three decades led to an intensive use of N fertilizers in many agricultural systems. Environmental and economic issues associated with such practices have, however, generated an interest in alternative management systems. These include practices such as exploitation of beneficial biological functions (symbiotic nitrogen fixation, etc.) and substitution of chemical fertilizers with farm-generated products.

Essential tremor: response to primidone.

<h3>ABSTRACT</h3> Soil microbial community and enzyme activities together affect various ecosystem functions of soils. Fertilization, as important agricultural management practices, are known to modify soil microbial characteristics; however, inconsistent results have been reported. The aim of this research therefore was to make a comparative study of the effects of different fertilization patterns (No N inputs (No N), 100% chemical fertilizer-N (CN) inputs (4/4CN) and different substitution rates of CN by organic manure-N (MN) (3/4CN+1/4MN, 2/4CN+2/4MN and 1/4CN+3/4MN)) on soil physicochemical properties, enzyme activities and microbial attributes in a GVP of Tianjin, China. Manure substitution of chemical fertilizer, especially at higher substitution rate (2/4CN+2/4MN and 1/4CN+3/4MN), improved soil physicochemical properties (higher soil organic C (SOC) and nutrient contents; lower bulk densities), promoted microbial growth (higher total phospholipid fatty acids and microbial biomass C contents) and activity (higher soil hydrolase activities). Manure addition caused a remarkable increase of the fungi/bacteria ratio and a distinct shift in the fungal (bacterial) community to greater abundance of arbuscular mycorrhizal fungi (G+ bacteria) compared with saprotrophic fungi (G− bacteria). These changes drove shifts toward fungal-dominated soil microbial communities and then optimized microbial community structure. Also, manure application increased soil biodiversity (microbial community and enzyme function), indicated by increased Shannon–Wiener diversity. Redundancy analysis indicated that the most possible mechanism of the impacts of different fertilization patterns on soil microbial characteristics may be the mediation of SOC and nutrient (N) availability (especially SOC) in this GVP of China. In conclusion, manure substitution of chemical fertilizer, especially at higher substitution rate, was more efficient for improving soil quality and biological functions.