Fertilizer Intensification Research Articles

Impact of urea fertilization rates on nitrogen losses, productivity and profitability in East African sugarcane plantations

AbstractFertilizer‐intensive sugarcane plantations are expanding in sub‐Saharan Africa (SSA) amidst increased groundwater pollution and carbon footprint concerns. Yet, the impact of nitrogen (N) levels on N losses, productivity and profitability in these plantations remains unclear. To address this gap, we conducted a completely randomized design experiment in a Ugandan sugarcane plantation using three N fertilization rates (low, standard and high) as treatments. N leaching under the different treatments was determined using the average drainage fluxes across a 1‐m‐layered profile which we estimated with a suite of pedotransfer functions (PTFs) and leachate N concentrations from suction cup lysimeters. Soil nitrous oxide fluxes were determined using static vented chamber bases and gas chromatography. Partial factor crop productivity was estimated from the average field fresh weight under each treatment and the amount of N fertilizer applied, while the return on investment was determined from the factory price of the field fresh weight and the market price of fertilizers. Our findings indicate that three out of five PTFs effectively estimated soil hydraulic properties at our test site, based on the close match between measured and predicted soil matric potential values. Notably, N leaching at low and standard N rates were comparable but significantly lower than at higher‐than‐standard N rates. Additionally, we measured comparable soil nitrous oxide emissions and field fresh weight but partial factor productivity and return on investment declined along the fertilizer intensification gradient. In conclusion, the study demonstrates the promising application of certain PTFs in N‐leaching modelling in the data‐scarce SSA. Furthermore, obtaining comparable field fresh weight with minimal N losses at lower‐than‐standard N rates presents an opportunity to mitigate groundwater pollution and greenhouse gas emissions. However, the potential impact of the switch from standard to low N rates on soil organic carbon stocks and sugarcane yields warrants further investigation.

Silvicultural intensification has a limited impact on tree growth in forest restoration plantations in croplands

Investigating the impact of silvicultural practices on tropical forest restoration plantations is highly relevant, as there is a growing global demand for large-scale ecological restoration. The objective of this study was to test the hypothesis that native trees respond positively to the intensification of fertilization and weed control in a forest restoration plantation on a site previously used as cropland in the Atlantic Forest region of Brazil. We carried out a study with 22 native tree species, 11 of which were classified as shade species and the other 11 classified as diversity species. We implemented a randomized experimental design in a split-plot design, with six replicates of four treatments: intensive weed control (glyphosate spraying every 3 months) with and without fertilization, and non-intensive control (mechanical control every 6 months), with and without fertilization. We performed fertilization by supplying the site with 53 kg ha−1 of nitrogen, 35 kg ha−1 of phosphorus, and 51 kg ha−1 of potassium. We evaluated individual tree crown areas and increments in basal diameter and height 16 months after planting. In general, growth varied more among species than in weed control and fertilization treatments. Overall, the method of controlling weeds did not influence tree growth, but interacted with species for all growth variables. Fertilization increased tree diameter increment, and interacted with species, leading to diameter and height increments; however, most of the species did not respond to fertilization. Contrary to our expectations and previous findings, silvicultural intensification did not promote higher overall tree growth, probably because the restoration planting was conducted on a cropland with decades of intensive management, which increased soil fertility and reduced weed abundance through periodical maintenance prior to restoration planting. Our results highlight the importance of considering local and historical conditions to decide whether and when management intensification is required to accelerate tree growth in tropical forest restoration plantations.

Does Credit Influence Fertilizer Intensification in Rice Farming? Empirical Evidence from Côte D’Ivoire

In Côte d’Ivoire, the use of fertilizers in rice farming still remains low. Credit constraints have been frequently reported as the main reason hampering rice farmers from reversing this situation. However, there is no empirical evidence on the link between rice farmers’ access to credit (AC) and fertilizer intensification (FI). This article examines this issue by using a sample of 600 rice farmers randomly selected in seven rice areas. Data are analyzed by the IV-Probit and IV-Tobit models. The results reveal that FI and AC reciprocally influence each other, implying that they are endogenous. An increase of credit by XOF 100 could increase the quantity of fertilizer used by 2.70 kg, all other things being equal. Moreover, FI and AC are strongly influenced by some socio-economic, rice farm, and institutional factors. Policymakers should take actions to facilitate rice farmers’ access to credit and subsidized fertilizers. Other relevant explanatory variables should be considered in rice farming development policies. By providing empirical evidence of the link between rice farmers’ access to credit and fertilizer intensification in Côte d’Ivoire, this paper contributes to the agricultural finance literature.

Spatially-explicit effects of seed and fertilizer intensification for maize in Tanzania

Slower than desired growth in crop yields coupled with rising food demand present ongoing challenges for food security in Africa. Some countries, such as Tanzania, have signed the Malabo and Abuja Declarations, which aim to boost food security through increasing crop productivity. The more intensive use of seed and fertilizer presents one approach to raising crop productivity. Our simulation study examined the productivity and economic effects of planting different seed cultivars and increasing fertilizer application rates at multiple spatial scales for maize in Tanzania. We combined crop simulation modelling with household data on costs and prices to examine field-scale and market-scale profitability. To scale out our analysis from the field scale to the regional and national scale (market scale) we applied an economic surplus model. Simulation results suggest that modest changes in seed cultivars and fertilizer application rates can double productivity without having a negative effect on its stability. The profitability of applying extra fertilizer, calculated as its value-cost ratio, increased if improved seed cultivars replaced local seed cultivars. Rankings of district-scale profits differed from rankings of district scale yields, highlighting the importance of considering economic factors in assessments of input intensification. At the national scale, simulation results suggest the total benefit could be US$ 697 million over 5 years if there was a 39 percent adoption rate of planting improved seed and applying extra mineral fertilizer. Providing economic assessments of input intensification helps build evidence for progressing the Malabo and Abuja Declarations.

PENYULUHAN MASTITIS SUBKLINIS PADA SAPI PERAH DI DESA MEKAR BAKTI KECAMATAN PAMULIHAN KABUPATEN SUMEDANG JAWA BARAT

Subclinical mastitis is an inflammation of the udder that often attacks livestock, especially milk-producing livestock. The impact of the loss of subclinical mastitis is quite large, including a dramatic decrease in the quantity and quality of milk, but no pathological changes in cattle have been found. Mekar Bakti Village, located in Pamulihan Subdistrict, Sumedang Regency, West Java, is one of the villages that is the center for producing milk in the Sumedang Region. The high incidence of subclinical mastitis encourages counseling regarding subclinical mastitis. Promotion activities were carried out by presenting material about subclinical mastitis with lecture techniques (power point slides), videos and discussion. In addition, efforts to increase livestock yields were carried out by giving information on the technique of making "Liquid Organic Cattle Fertilizer Intensification" (PITSA OC) and training in making pasteurized cow milk. This series of counseling activities is an effort to reduce the incidence of subclinical mastitis through increasing community knowledge.

Integrated approach for managing fertilizer intensification linked environmental issues

PurposeThe purpose of this paper is to understand the critical factors associated with growing fertilizer usage culminating in contamination of soil/water in agriculturally intensive regions of Uttar Pradesh, India. The agriculture sector is seen as one of the major contributors in ensuring food security, however adoption of sustainable agriculture to protect water resources from contamination due to fertilizers and pesticides is becoming pressing to achieve long term environmental security.Design/methodology/approachA two staged study aimed at monitoring the soil quality status followed by stakeholder survey has been attempted. Attitude-behavior framework based on the theory of reasoned action has been tried to explain the fertilizer use behavior in the study. The results are analyzed through Analysis of variance.FindingsSoil monitoring data showed nitrate and total nitrogen loadings beyond the permissible limit in the identified regions. A questionnaire aimed at determining farmer’s attitude toward fertilizer usage showed a significant influence of factors like net farm income, overall farm yield, extension services, farmer characteristics on one hand and risks associated with changing farming practices, costs of substitutes available, market-based instruments like subsidies and loans on the other. Divergent responses were observed with respect to farmer’s perceived risks from adopting to organic substitutes, linkages of fertilizer application with environmental degradation and the level of adoption of sustainable agricultural practices.Research limitations/implicationsThe study can be scaled up to study the inter-regional differences by benchmarking regional responses. It would be interesting to extend the work to find solutions from the farmers as alternative fertility management strategies. The items used in questionnaire are self-made; hence there is still a possibility of enhancing the robustness of scale by applying advanced statistical techniques.Practical implicationsResults of the study indicate excessive nitrogen loadings in farm soils which is an indicator of potential future nitrate contaminated zones or vulnerable zones emerging in agricultural intensive regions. Findings reinforce the role of education, knowledge transfer and awareness for long-term agricultural sustainability. The paper highlights the urgency for reorientation of the support system by the government and policymakers.Originality/valueThe paper attempts to understand the linkage between the agricultural productivity and the environmental implications followed by the reasons culminating in the agri-environmental imbalance. On-site monitoring study followed by assessment of reasons culminating in this scenario has not been attempted earlier and this paper contributes to understanding at dual level. This paper emphasizes on the insights of stakeholder which is instrumental in ensuring agricultural sustainability or otherwise. It takes the position that the farmer’s farm management behavior is strongly influenced by factors like food security and income, keeping environmental quality at second place. It also identifies the barriers for organic farming and other alternative systems as well as explores the economic, social, and philosophical aspects of sustainable agriculture.

Análise energética do novo sistema de produção de maracujá amarelo na região de Marília-SP

Objetivou-se avaliar indicadores energéticos de um novo sistema de produção do maracujá amarelo na região de Marília-SP. Foram analisadas as "entradas" de energia de origem biológica, fóssil e industrial e a "saída" energética na forma de frutos produzidos por unidade de área, bem como cinco indicadores energéticos. A entrada energética totalizou 155.810,13 MJ/ha. Os adubos químicos e defensivos responderam por 71% e 24% da energia indireta industrial, respectivamente. A atividade gerou, por ciclo/ha, 587.700,00MJ, sendo a produtividade cultural 0,19MJ kg-1. A eficiência cultural foi de 3,77. A energia cultural líquida totalizou 431.889,87 MJ/ha. A eficiência energética (4.17) e o balanço energético (550.312,91MJ ha-1) foram positivos. Concluiu-se que o consumo de energia direta de origem fóssil, mesmo que significativo, ainda permite a produção do fruto de maneira ambientalmente sustentável. Os adubos químicos e defensivos foram os itens mais representativos da energia indireta industrial, em decorrência da intensificação da adubação como forma de prevenção de doenças.

Biodiversity can support a greener revolution in Africa

The Asian green revolution trebled grain yields through agrochemical intensification of monocultures. Associated environmental costs have subsequently emerged. A rapidly changing world necessitates sustainability principles be developed to reinvent these technologies and test them at scale. The need is particularly urgent in Africa, where ecosystems are degrading and crop yields have stagnated. An unprecedented opportunity to reverse this trend is unfolding in Malawi, where a 90% subsidy has ensured access to fertilization and improved maize seed, with substantive gains in productivity for millions of farmers. To test if economic and ecological sustainability could be improved, we preformed manipulative experimentation with crop diversity in a countrywide trial (n = 991) and at adaptive, local scales through a decade of participatory research (n = 146). Spatial and temporal treatments compared monoculture maize with legume-diversified maize that included annual and semiperennial (SP) growth habits in temporal and spatial combinations, including rotation, SP rotation, intercrop, and SP intercrop systems. Modest fertilizer intensification doubled grain yield compared with monoculture maize. Biodiversity improved ecosystem function further: SP rotation systems at half-fertilizer rates produced equivalent quantities of grain, on a more stable basis (yield variability reduced from 22% to 13%) compared with monoculture. Across sites, profitability and farmer preference matched: SP rotations provided twofold superior returns, whereas diversification of maize with annual legumes provided more modest returns. In this study, we provide evidence that in Africa, crop diversification can be effective at a countrywide scale, and that shrubby, grain legumes can enhance environmental and food security.

Modeling carbon dynamics in vegetation and soil under the impact of soil erosion and deposition

Soil erosion and deposition may play important roles in balancing the global atmospheric carbon budget through their impacts on the net exchange of carbon between terrestrial ecosystems and the atmosphere. Few models and studies have been designed to assess these impacts. In this study, we developed a general ecosystem model, Erosion‐Deposition‐Carbon‐Model (EDCM), to dynamically simulate the influences of rainfall‐induced soil erosion and deposition on soil organic carbon (SOC) dynamics in soil profiles. EDCM was applied to several landscape positions in the Nelson Farm watershed in Mississippi, including ridge top (without erosion or deposition), eroding hillslopes, and depositional sites that had been converted from native forests to croplands in 1870. Erosion reduced the SOC storage at the eroding sites and deposition increased the SOC storage at the depositional areas compared with the site without erosion or deposition. Results indicated that soils were consistently carbon sources to the atmosphere at all landscape positions from 1870 to 1950, with lowest source strength at the eroding sites (13 to 24 gC m−2 yr−1), intermediate at the ridge top (34 gC m−2 yr−1), and highest at the depositional sites (42 to 49 gC m−2 yr−1). During this period, erosion reduced carbon emissions via dynamically replacing surface soil with subsurface soil that had lower SOC contents (quantity change) and higher passive SOC fractions (quality change). Soils at all landscape positions became carbon sinks from 1950 to 1997 due to changes in management practices (e.g., intensification of fertilization and crop genetic improvement). The sink strengths were highest at the eroding sites (42 to 44 gC m−2 yr−1), intermediate at the ridge top (35 gC m−2 yr−1), and lowest at the depositional sites (26 to 29 gC m−2 yr−1). During this period, erosion enhanced carbon uptake at the eroding sites by continuously taking away a fraction of SOC that can be replenished with enhanced plant residue input. Overall, soil erosion and deposition reduced CO2 emissions from the soil into the atmosphere by exposing low carbon‐bearing soil at eroding sites and by burying SOC at depositional sites. The results suggest that failing to account for the impact of soil erosion and deposition may potentially contribute to an overestimation of both the total historical carbon released from soils owing to land use change and the contemporary carbon sequestration rates at the eroding sites.