Timing Of Fertilizer Application Research Articles

A Study on the Impacts of Fertilizer Crisis on Paddy Cultivation in Five Selected Divisional Secretariat Divisions of Trincomalee District During Maha 2021/22

Rice is one of the most important cereal crops in the world. With population growth, farmers have to increase paddy production to meet existing as well as future demand. Fertilizer is the major input in rice production. Growth and yield traits of rice are affected by improper and imbalanced application of plant nutrients. Hence, suitable practices of adequate rate and timing of fertilizer application are needed to increase the rice yield. In May 2021, Imports & Exports (Control) Regulation No 07 of 2021 was issued, banning the importation of chemical fertilizers, pesticides, & herbicides in Sri Lanka. Low fertility of paddy soil created the need for adequate and constant supply of chemical fertilizers in paddy cultivation, which is a major threat to production and endangers the national food security and economy of Sri Lanka, especially in the major cropping season of Maha 2021/22. Therefore, a questionnaire survey was conducted to investigate the impact of the fertilizer crisis in major paddy-cultivating Divisional Secretariat divisions of the Trincomalee district. The random sampling method was used to select respondents for the survey, and the collected data were statistically analyzed by SPSS version 26.0 software. The results revealed that the majority of the farmers experienced a 50% yield reduction compared to the last cropping season of Maha 2020/21 in the entire five DS divisions. The seedling stage was highly affected during the fertilizer crisis in paddy cultivation in all five DS divisions. Further, the cost of production in paddy cultivation increased by more than 50% during the fertilizer crisis compared to the cost involved in Maha 2020/21. The potential for organic manure production is very poor, while the majority of farmers are interested in adopting the sustainable farming system of the Integrated Plant Nutrient System through the judicious application of chemical and organic fertilizers received on a subsidy basis, according to the present government’s fertilizer policy, which emphasizes 70% of inorganic fertilizers and 30% of organic manure application to improve sustainability in paddy cultivation in the country.

Recycled Iron Phosphates: A New Phosphorus Fertilizer for Paddy Rice.

The potential of recycled iron phosphates (FePs), e.g., vivianites (Fe3(PO4)2·8H2O) and Fe(III)-rich phosphorus (P) adsorbent materials, as phosphorus fertilizer is limited by the strong interaction between Fe and P. In this study, the efficiency of FePs as P fertilizer was explored by applying them as granules or powder in flooded strongly P-fixing soils (acid and calcareous), thereby taking advantage of increased P release induced by reductive dissolution of P-bearing Fe(III) minerals. First, no P diffusion from granular FeP fertilizers into flooded soils was detectable by the diffusive gradient in thin films (DGT) technique and microfocused X-ray fluorescence (μ-XRF) analysis of thin soil sections, in contrast to detectable P diffusion away from granules of soluble triple superphosphate (TSP) fertilizer. On the contrary, powdered FePs demonstrated an excellent increase in extractable P (1 mM CaCl2) in a 120-day incubation experiment in flooded soils. Second, a pot experiment was performed with rice (Oryza sativa) grown in flooded acid and calcareous soils. The fertilizer value of FePs was remarkable when dosed as powder, as it was even up to 3-fold higher than TSP in the acid soil and similar to TSP in the calcareous soil. The beneficial effect of FeP over TSP in the acid soil is attributed to the slow release of P from FePs, which allows to partly overcome P fixation. The promising results of FePs as P fertilizer applied as powders in flooded soils debunk the generally accepted idea that FePs are poor sources of P while demonstrating the importance of the timing of FeP fertilizer application.

Corn 15N uptake and partitioning in response to fertilizer application rate and timing

AbstractNitrogen (N) fertilizer applications near the time of planting are important for upper US Midwest corn (Zea mays L.) production, but wet springs may result in significant N losses. Split applications may circumvent this problem and improve fertilizer uptake and use efficiency, but the relative contribution of N from the soil and fertilizer is poorly understood. A field study with six sites in Minnesota received 15N‐labeled urea fertilizer in the first year and unlabeled urea in the second year to determine the effect of N rate and application timing on corn uptake and accumulation patterns of fertilizer‐derived N (FDN) and soil‐derived N (SDN) over two consecutive growing seasons. Corn responded positively to fertilization. The percentage of total N uptake as FDN was greatest closest to the time of application but decreased over time as SDN became the dominant N source. A split application (45 kg N ha−1 at planting, 90 kg N ha−1 at V4) significantly improved FDN uptake over the 135 kg N ha−1 preplant treatment but did not improve total N uptake in the first year at any site. Fertilizer‐N use efficiency (F15NUE) using the isotopic method was 2.8%–43.3% across all sites at the end of the first year with the majority partitioned to the grain. At the end of the second year, approximately 2.2% of the first‐year applied FDN was recovered in aboveground biomass. Fertilization ensures adequate N availability to the developing crop, but ultimately SDN contributed ≥61% of the total N uptake.

Effect of type and time of fertilizer application in foliar fertilization on production and seed quality of cayenne (Capsicum frutescens L. var. Bonita)

Cayenne (Capsicum frutescens L.) classified as a horticultural crop that has high economic value. The use of fertilizer can affect the maximum growth and production of cayenne plants, so it is necessary to know the right type and time. The purpose of the study was to find the best type and time of fertilizer application for the production and quality of cayenne seeds. This study used a randomized block design with two treatment factors, the first factor was the type of fertilizer, namely Gandasil B fertilizer, Bayfolan, White KNO3 and NPK Mutiara, the second factor was the time of fertilizer application, namely fertilizer application during flowering, as well as during flowering and fruit enlargement. The results showed that the interaction between the type and time of fertilizer application had a very significant effect on the total sugar content of leaves. Fertilizer treatment has a very significant effect on the total sugar content of leaves, has a significant effect on the number of fruits per plant, weight per fruit, growth uniformity, percentage of normal and abnormal sprouts, and germination. The best type of fertilizer for fruit production is Bayfolan while judging from seed quality, the best type of fertilizer for seed production is NPK Mutiara. The timing of fertilizer application had a very significant effect on the total sugar content of the leaves but had no significant effect on other variables. The best application time for seed production is fertilizer application during flowering plants and fruit enlargement.

Nitrogen fertilizer source, rate, placement, and application timing effect on sorghum (grain and forage) and corn grain yields

AbstractIdentifying the limiting nutrient, fertilizer source, rate, placement, additives, and timing of application are critical components of fertilizer management. The objective of this study was to quantify the impact of nitrogen (N) fertilizer source, rate, placement method, additives, application timing, and environment on yields of grain sorghum, forage sorghum [Sorghum bicolor (L.) Moench], and corn (for grain, Zea mays L.). Independent field experiments were conducted at 13 different environments in Kansas from 2008 through 2013 on grain sorghum, forage sorghum, and corn. Treatments were an incomplete factorial combination of four fertilizer placement methods, three fertilizer types, five fertilizer additives, three fertilizer application times, and six fertilizer rates that varied by location and across years. Results showed grain and forage sorghum yields responded to N fertilizer in environments that were not extremely dry (<136 mm) or wet (>651 mm). Corn responded to N fertilizer application only in high‐precipitation environments. For grain sorghum, where rate × placement × source × additive interaction was significant, broadcast application of urea (source) at high rates (67–134 kg N ha−1), with summer application timing, or with additive in winter (with environmentally smart nitrogen [ESN]) resulted in up to 43% greater yield compared with application of urea‐ammonium nitrate (UAN; source) and surface band (placement) at 67 kg ha−1 without additives. In the one site‐year where forage sorghum responded to fertilizer application, forage yields with preplant application of UAN at 56–140 kg ha−1 were 164% greater than the control. For corn, application of either urea or UAN fertilizer, UAN in coulter or surface band, with ESN blend, applied at planting, and at highest rates (160 kg ha−1) resulted in best yields compared with the alternatives and 110% greater yield compared with the unfertilized control. We concluded that fertilizer rate is an important management component as it consistently affected yield regardless of crop considered. Fertilizer placement and timing have crop‐specific importance as they were significant for only corn, but the main effect of additives (N stabilizers) was not significant for any of the crops. Environment and crop type influenced crop response to N fertilizer rate, timing, placement, and additives.

Evaluating responses by ChatGPT to farmers’ questions on irrigated lowland rice cultivation in Nigeria

The limited number of agricultural extension agents (EAs) in sub-Saharan Africa limits farmers’ access to extension services. Artificial intelligence (AI) assistants could potentially aid in providing answers to farmers’ questions. The objective of this study was to evaluate the ability of an AI chatbot assistant (ChatGPT) to provide quality responses to farmers’ questions. We compiled a list of 32 questions related to irrigated rice cultivation from farmers in Kano State, Nigeria. Six EAs from the state were randomly selected to answer these questions. Their answers, along with those of ChatGPT, were assessed by four evaluators in terms of quality and local relevancy. Overall, chatbot responses were rated significantly higher quality than EAs’ responses. Chatbot responses received the best score nearly six times as often as the EAs’ (40% vs. 7%). The evaluators preferred chatbot responses to EAs in 78% of cases. The topics for which the chatbot responses received poorer scores than those by EAs included planting time, seed rate, and fertilizer application rate and timing. In conclusion, while the chatbot could offer an alternative source for providing agricultural advisory services to farmers, incorporating site-specific input rate-and-timing agronomic practices into AI assistants is critical for their direct use by farmers.

A global meta-analysis of yield-scaled N2 O emissions and its mitigation efforts for maize, wheat, and rice.

Maintaining or even increasing crop yields while reducing nitrous oxide (N2 O) emissions is necessary to reconcile food security and climate change, while the metric of yield-scaled N2 O emission (i.e., N2 O emissions per unit of crop yield) is at present poorly understood. Here we conducted a global meta-analysis with more than 6000 observations to explore the variation patterns and controlling factors of yield-scaled N2 O emissions for maize, wheat and rice and associated potential mitigation options. Our results showed that the average yield-scaled N2 O emissions across all available data followed the order wheat (322 g N Mg-1 , with the 95% confidence interval [CI]: 301-346) > maize (211 g N Mg-1 , CI: 198-225) > rice (153 g N Mg-1 , CI: 144-163). Yield-scaled N2 O emissions for individual crops were generally higher in tropical or subtropical zones than in temperate zones, and also showed a trend towards lower intensities from low to high latitudes. This global variation was better explained by climatic and edaphic factors than by N fertilizer management, while their combined effect predicted more than 70% of the variance. Furthermore, our analysis showed a significant decrease in yield-scaled N2 O emissions with increasing N use efficiency or in N2 O emissions for production systems with cereal yields >10 Mg ha-1 (maize), 6.6 Mg ha-1 (wheat) or 6.8 Mg ha-1 (rice), respectively. This highlights that N use efficiency indicators can be used as valuable proxies for reconciling trade-offs between crop production and N2 O mitigation. For all three major staple crops, reducing N fertilization by up to 30%, optimizing the timing and placement of fertilizer application or using enhanced-efficiency N fertilizers significantly reduced yield-scaled N2 O emissions at similar or even higher cereal yields. Our data-driven assessment provides some key guidance for developing effective and targeted mitigation and adaptation strategies for the sustainable intensification of cereal production.

Annual Urea Nitrogen Contribution to the Nutrition of Cabernet Sauvignon Grapevine Grown in Sandy and Clayey Soil

The timing of nitrogen fertilizer application in vineyards can determine the amount of nitrogen (N) absorbed, distributed, and accumulated in grapevine organs. The study aimed to evaluate the annual contribution of N from urea, applied at different times in Cabernet Sauvignon, grown in sandy and clayey soil in a subtropical climate. The sandy soil received 21.42 kg N ha−1 and the clayey soil 30 kg N ha−1, both enriched with 3% excess 15N atoms, applied at different times. The N derived from the fertilizer in grapevines, at all times of N application, and in sandy and clayey soil did not exceed 8%, with the highest values being observed in annual organs, especially in the leaves. The application of N marked at the phenological stages of IBB (50% at beginning of budbreak + 50% at full budbreak) enabled greater absorption of N derived from the fertilizer by the vines grown in both sandy and loamy soil. The N present in the annual organs (leaves, berries, stalks, and shoots) and in the perennial organs (stems and canes) of Cabernet Sauvignon grown in sandy and clayey soil was derived in greater percentages from the soil.

NITROGEN FERTILIZER APPLICATION TIME EFFECT ON THE SENESCENCE AND GRAIN YIELD OF DURUM WHEAT (TRITICUM DURUM DESF.)

The experiment progressed to evaluate the effects of time nitrogen fertilizer application on the senescence of durum wheat and its association with grain yield and its components. The experimental treatments, set up in a split-plot design, used five durum wheat cultivars (Adnham, Grecale, Duma, Sardar, Svevo) as the main plots, and the time nitrogen fertilizer application (100% tillering, 100% stem elongation, and 50% tillering + 50% stem elongation stages) under two locations in Northern Iraqi conditions. The results of this study indicated that late senescence cultivars (Grecale and Svevo) produced the highest flowering date (123.89 and 123.61 days), number of spikes/m2 (267.2 and 265.6 spikes), number of grains/10 spikes (330.5 and 323.6 grains), grain yield g/m2 (532.2 and 511.6 g), and harvest index% (38.72% and 39.86%). Moreover, the time of nitrogen fertilizer application at the tillering stage (early application) influenced most of the studied traits. Finally, extending photosynthesis capacity during the grain-filling phases by delaying the rate of senescence could be a better approach to improving the grain yield of wheat cultivars.

Financial Feasibility and Sensitivity of Arabica Coffee Farming In Simalungun District, Sumatra Utara Province

Arabica coffee productivity in Simalungun Regency has the highest value, namely 1.25 tons/ha, among other arabica coffee producing districts in Sumatra Utara Province. However, the level of feasibility of return on investment made by farmers of arabica coffee has not been measured. The research method used to determine the feasibility and sensitivity of arabica coffee farming is Net B/C ratio, Gross B/C ratio, Profitability Ratio, Net Present Value and Internal Rate of Return. The results of the research show that arabica coffee farming is financially feasible based on the criteria of Net B/C Ratio (2.33), Gross B/C Ratio (1.38), Profitability Ratio (2.31), NPV (Rp. 23,194,329), and IRR (25.06%). The sensitivity of arabica coffee farming occurs if fertilizer and labor costs increase by 55% and production prices fall, then arabica coffee farming is not worth pursuing. Arabica coffee farming in Raya Huluan Village is financially feasible but farmers have not been able to independently cultivate arabica coffee properly. Therefore, farmers are given assistance on how to cultivate arabica coffee farming, types of fertilizer and dosage of fertilizer, timing of fertilizer application so that the economic life of arabica coffee is more than 10 years.

Insights into soil NO emissions and the contribution to surface ozone formation in China

Abstract. Elevated ground-level ozone concentrations have emerged as a major environmental issue in China. Nitrogen oxide (NOx) is a key precursor to ozone formation. Although control strategies aimed at reducing NOx emissions from conventional combustion sources are widely recognized, soil NOx emissions (mainly as NO) due to microbial processes have received little attention. The impact of soil NO emissions on ground-level ozone concentration is yet to be evaluated. This study estimated soil NO emissions in China using the Berkeley–Dalhousie Soil NOx Parameterization (BDSNP) algorithm. A typical modeling approach was used to quantify the contribution of soil NO emissions to surface ozone concentration. The brute-force method (BFM) and the Ozone Source Apportionment Technology (OSAT) implemented in the Comprehensive Air Quality Model with Extensions (CAMx) were used. The total soil NO emissions in China for 2018 were estimated to be 1157.9 Gg N, with an uncertainty range of 715.7–1902.6 Gg N. Spatially, soil NO emissions are mainly concentrated in Central China, North China, Northeast China, the northern Yangtze River Delta (YRD), and the eastern Sichuan Basin, with distinct diurnal and monthly variations that are mainly affected by the temperature and timing of fertilizer application. Both the BFM and OSAT results indicate a substantial contribution of soil NO emissions to the maximum daily 8 h (MDA8) ozone concentrations by 8.0–12.5 µg m−3 on average for June 2018, with the OSAT results being consistently higher than the BFM results. The results also showed that soil NO emissions led to a relative increase in ozone exceedance days by 10.5 %–43.5 % for selected regions. Reducing the soil NO emissions resulted in a general decrease in monthly MDA8 ozone concentrations, and the magnitude of ozone reduction became more pronounced as reductions increased. However, even with complete reductions in soil NO emissions, approximately 450.3 million people are still exposed to unhealthy ozone levels, necessitating multiple control policies at the same time. This study highlights the importance of soil NO emissions for ground-level ozone concentrations and the potential for reducing NO emissions as a future control strategy for ozone mitigation in China.

Response of Soft Wheat Varieties to Application Time of Nitrogen Fertilizer under Mediterranean Climate Conditions

Applying nitrogen fertilizer during the appropriate time is an opportunity to reduce the application amount and improve its availability in the plant, which reduces the costs of Agriculture and environmental pollution. The experiment was carried out in the winter agricultural season 2020-2021 at two sites (Nimrud and Bashiqa) to study the response of soft wheat varieties to different application time of Nitrogen fertilizer under the Mediterranean climate conditions. The experiment included four soft wheat varieties (Benghal, Ebaa-99, Rashida, Tal-Afar), three application time of Nitrogen fertilizer at tillering stage (early application), stem elongation stage (late application) as well as control treatment (no application). The results showed that the Bashiqa site excelled at grain filling stage duration, bio yield, spike number, grain yield, harvest index, while the Nimrod site excelled in the rest of the traits. The Benghal variety excelled in the majority of studied traits at both sites, while application time of Nitrogen fertilizer of stem elongation stage (late application) excelled of the majority studied traits.

Crop production and water quality under 1.5 °C and 2 °C warming: Plant responses and management options in the mid-Atlantic region

The 2015 “Paris Agreement” aims to limit the global average temperature rise to significantly less than 2 °C, preferably within 1.5 °C above pre-industrial levels. A multitude of studies have focused on evaluating how different sectors respond to such levels of warming. Nonetheless, most of these studies fail to provide a clear roadmap to mitigate these impacts. A case in point is the anticipated decline in corn and soybean yields and increased phosphorus (P) and nitrogen (N) discharge into water bodies, a trend linked to past agricultural practices and climate change. In this research, we employ a novel assessment of how existing management practices under 1.5 °C and 2 °C global warming (GW) scenarios can affect nutrient availability in time and space as well as crop yield in a typical agricultural watershed in the Mid-Atlantic Region, specifically the Upper Maurice River Watershed (UMRW) in New Jersey.Using the Soil and Water Assessment Tool (SWAT) with multiple Global Climate Model (GCM) projections, we found that compared to 1.5 °C, a 2 °C GW scenario would exacerbate runoff, leading to amplified nutrient leaching. These losses decrease nutrient availability during the crop growing season. Moreover, a mismatch between the timing of fertilizer application and crop nutrient absorption caused nutrient-related stress. This nutrient and anticipated temperature stress resulted in a more significant decrease in crop yields under the 2 °C GW scenario than the 1.5 °C scenario. We have designed a management scenario to reduce future nutrient losses while increasing crop yields. The strategy involves altering the timing of planting/harvesting and the fertilizer application rate in response to a warming climate. This approach is projected to increase corn and soybean yields by +39 % (+21 %) and +2 % (+17 %), respectively, under the 1.5 °C (2.0 °C) GW scenario for the RCP-4.5 pathway. Simultaneously, it is expected to decrease the N and P loads at 1.5 °C (2.0 °C) GW. Comparable projections are also observed under the RCP-8.5 pathway.

Effects of Nanofertilizer Applications at Different Growth Stages of Sweet Corn (Zea mays var. saccharata) on Biochemical Stress Factors

Background: Nanofertilizers are known to be more effective than other types of fertilizers. The present study aims to determine the biochemical stress parameters and yield values obtained when different nanofertilizer applications and doses were applied at different times in sweet corn. Methods: This study was carried out in Antalya, Turkey during the 2020-2021 corn production season. The effects of different nanofertilizer applications on the yield and quality of the Rain Hazar F1 corn variety were investigated. The present study employed 3 different fertilizer application times (3-leaf stage, 12-leaf stage and corn tasseling season), 4 different nanofertilizers (nano-zinc, nano-molybdenum, nano-boron and nano-iron) and 2 different fertilizer doses (125 ppm and 200 ppm). The study was set up using the split-plot design in randomized blocks with 3 replications. Result: The total phenolic content ranged between 271.90±1.51 and 118.80±12.47 mg GAE/g. The total antioxidant content ranged between 87.22±4.58 and 60.39±2.54%. The ascorbic acid peroxidase activity ranged between 4.54±1.46 and 0.17±0.01 EU/mg protein. The total chlorophyll content ranged between 7.43±1.96 and 1.97±0.09 mg/g. It was found in the present study that nanofertilizers can have a significant effect on the growth and development of corn plants.

Rice brown planthopper monitoring and detection by spectral reflectance: a review

Brown planthopper (BPH) has been one of the main pests of rice worldwide. Monitoring is important factor for determining attacks and estimating their effects. The traditional monitoring approach is usually conducted through visual observation and field scouting, with limitations such as subjectivity and time consumption. Remote sensing is an alternative pest monitoring method that covers a larger area in a shorter time. This paper discusses a remote-sensing method that uses a spectral approach to detect BPH attacks. Literature was filtered and processed using the PRISMA method. According to the spectral sensor, studies were classified into multispectral and hyperspectral sensors. Based on this scale, there are four studies on the panicle, leaf, canopy, and field levels. The model used single-wave reflectance and spectral indices as predictors. Various algorithms were used in the studies: linear regression, Principal Component Analysis, and Machine Learning to estimate the severity class, BPH Population density, and yield loss. A combination of spectral reflectance with other parameters, such as weather, fertilizer application, and infestation time, was conducted to improve the performance of the detection model. This review provides state-of-the-art spectral reflectance usage for detecting BPH attacks and opportunities for future development.

Effect of fertigation on nutrient dynamics of gray-brown soils and apple (Malus pumila) yields in intensive orchards of Kazakhstan

Over the past 13 years, drip irrigation in intensive orchards has gained popularity in southern Kazakhstan. However, its impact on soil has not been studied before. Our research group conducted experiments from 2019 to 2022 in intensive orchards to study the dynamics of fertigation, the application of fertilizers through irrigation water, on soil nutrient levels. Experiments were conducted in Southern Kazakhstan at "Kentau" LLP on intensive orchards with a planting scheme of 0.8*3.5m from 2019 to 2022 with the aim of determining the dynamics of the impact of fertigation on the content of available nutrient elements in the soil. The effectiveness of traditional root feeding method was compared with fertigation (drip application of mother liquor) on large areas of 136.5 hectares in laboratories at the Kazakh National Agrarian Research University and the Laboratory of TOO "KosAgroKommertz". Results showed that proper calculation of fertilizer doses for fertigation resulted in cyclic changes in soil nutrient levels (up to 23%), depending on the season and phenological phase of apple trees. The correlation between fruit quality and quantity was influenced by timing and assimilability of nutrients and method of application. Implementation of recommended fertilization methods resulted in increased yield, although the young age of some orchards may have contributed to the results. Under optimal nutrient management plans, nutrient levels in the soil showed noticeable fluctuations depending on the phenological phases of apple trees, which can be used to adjust fertigation practices. The study also revealed that fertigation can affect soil properties such as bulk density, soil density, and humus content, with potential long-term implications for soil health and fertility. In conclusion, fertigation significantly impacts soil nutrient levels in intensive orchards in southern Kazakhstan, and careful management of fertilizer doses and application timing is crucial for maximizing its effectiveness. Further research is needed to understand the long-term effects of fertigation on soil health and fertility, and its implications for sustainable agriculture practices. The findings contribute to knowledge on fertigation dynamics in Kazakhstan, serving as a basis for further studies and practical applications in agricultural management.

Assessing fertilizer nitrogen sources and application timing for water‐seeded rice systems

AbstractIn California's water‐seeded rice systems, both high yields and nitrogen (N) use efficiency are achieved when the pre‐plant N fertilizer (usually aqueous‐ammonia [aqua‐N]) is injected into a dry seedbed before flooding and planting. However, there are situations where applying N fertilizer in this manner is not possible. The objective of this study was to evaluate alternative N management practices by testing different N sources and application times. In 2020, we tested 13 treatments and in 2021, six more treatments were added. The following N sources were evaluated: urea, ammonium sulfate, and three enhanced efficiency nitrogen fertilizers (EENFs). Application times for the EENFs, urea, and ammonium sulfate were one day after flooding and 2 weeks after flooding. Urea and ammonium sulfate were also applied in a four‐way split. In 2021, additional treatments were added with aqua‐N, ammonium sulfate, and urea applied before flooding, and urea applications at 3, 4, and 5 weeks after flooding. Grain yield and agronomic nitrogen use efficiency (ANUE) were used for comparison. All fertilizer N treatments increased grain yields relative to the zero‐N control, which averaged 5093 kg ha−1. Applying aqua‐N or urea preplant to a dry soil resulted in the highest yields and ANUE. The EENF fertilizers performed similarly to or worse than urea applied alone. If the field was already flooded, splitting urea applications was the best option. Only one split N treatment was evaluated in this study; this warrants further research on fine‐tuning the best N splits for these systems.

Estimating nutrient concentrations and uptake in rice grain in sub-Saharan Africa using linear mixed-effects regression.

Quantification of nutrient concentrations in rice grain is essential for evaluating nutrient uptake, use efficiency, and balance to develop fertilizer recommendation guidelines. Accurate estimation of nutrient concentrations without relying on plant laboratory analysis is needed in sub-Saharan Africa (SSA), where farmers do not generally have access to laboratories. The objectives are to 1) examine if the concentrations of macro- (N, P, K, Ca, Mg, S) and micronutrients (Fe, Mn, B, Cu) in rice grain can be estimated using agro-ecological zones (AEZ), production systems, soil properties, and mineral fertilizer application (N, P, and K) rates as predictor variables, and 2) to identify if nutrient uptakes estimated by best-fitted models with above variables provide improved prediction of actual nutrient uptakes (predicted nutrient concentrations x grain yield) compared to average-based uptakes (average nutrient concentrations in SSA x grain yield). Cross-sectional data from 998 farmers' fields across 20 countries across 4 AEZs (arid/semi-arid, humid, sub-humid, and highlands) in SSA and 3 different production systems: irrigated lowland, rainfed lowland, and rainfed upland were used to test hypotheses of nutrient concentration being estimable with a set of predictor variables among above-cited factors using linear mixed-effects regression models. All 10 nutrients were reasonably predicted [Nakagawa's R2 ranging from 0.27 (Ca) to 0.79 (B), and modeling efficiency ranging from 0.178 (Ca) to 0.584 (B)]. However, only the estimation of K and B concentrations was satisfactory with a modeling efficiency superior to0.5. The country variable contributed more to the variation of concentrations of these nutrients than AEZ and production systems in our best predictive models. There were greater positive relationships (up to 0.18 of difference in correlation coefficient R) between actual nutrient uptakes and model estimation-based uptakes than those between actual nutrient uptakes and average-based uptakes. Nevertheless, only the estimation of B uptake had significant improvement among all nutrients investigated. Our findings suggest that with the exception of B associated with high model EF and an improved uptake over the average-based uptake, estimates of the macronutrient and micronutrient uptakes in rice grain can be obtained simply by using average concentrations of each nutrient at the regional scale for SSA. Further investigation of other factors such as the timing of fertilizer applications, rice variety, occurrence of drought periods, and atmospheric CO2 concentration is warranted for improved prediction accuracy of nutrient concentrations.

Determinants of Training Need of the Pineapple Growers for Boosting Production in Hilly Areas of Sreemangal Upazila Under Moulvibazar District

Training is a tool to increase production both vertically and horizontally through enhanced skills of the farmers. The focus of the study was to determine and describe the training need of the pineapple growers in a hilly area of Sylhet region and explores the relationship between the selected characteristics of growers and training need. Data were collected from randomly selected 75 pineapple growers out of 228 of three unions namely Sreemangal, Ashidron, and Sindhurkhan of Sreemangal upazila under Moulvibazar district using a pre-tested interview schedule from 1 September to 2 October 2020. Through Focus Group Discussion (FGD) with the growers, a total of 12 different aspects of pineapple cultivation were identified as inadequately skilled for modern pineapple cultivation. For quantification of training need, each respondent was asked to answer the extent of training need against each of those aspects. Results revealed that most of the pineapple growers (58.7%) had medium training need while 29.3% had high and only 12.0% had low training need. The top five training need aspects of pineapple cultivation were appropriate amount and time of fertilizer application, modern method of insect–pest identification and control, soil moisture conservation technique, and preventive measure of fruit sunburn. Correlation analysis indicated that age (-0.272*), educational (-0.526**), annual income (-0.269*), experience of pineapple cultivation (-0.455**), knowledge about pineapple cultivation (-0.807**), training received (-0.558**), and use of information source (-0.331**) were found negatively significant with their training need. Extension service providers should come forward to facilitate access of need-based information and skills to the pineapple growers or at least do their best alternative based on resource allocation for improvement of yield and production of pineapple in the hilly areas of Sylhet region.

Effects of Fertilizer Application Strategy Adjustments on Nitrogen and Phosphorus Loss from Typical Crop Systems in Taihu Lake Region

The intensity of crop farming fertilizer input is generally high in the Taihu Lake Region, with chemical fertilizer as the main form. Due to inappropriate fertilizer application, nitrogen and phosphorus loss have occurred, causing serious agricultural non-point source pollution. The Ministry of Agriculture and Rural Affairs of China has launched the "zero-growth action for chemical fertilizer use" and "replacement action with organic fertilizer" ("two actions" for short) campaigns since 2015. Local agricultural sectors adjusted fertilizer application strategies of crop farming to respond to the call of two actions. However, the current research is still focusing on reducing the total amount of fertilizer application and increasing the area of organic fertilizer application, which is mainly based on grain crops. The study of agricultural environment problems is still lacking, especially in vegetable, orchard, and tea systems. Therefore, a study was carried out in the typical agricultural area of Suzhou City Wuzhong District from 2019 to 2021. Based on the data of the amount of nitrogen and phosphorus removal by harvest crops and soil nitrogen and phosphorus residual in paddy, vegetable, orchard, and tea systems, the loss was estimated. The responses of nitrogen and phosphorus loss from typical crop systems to fertilizer application strategy adjustments were studied through analysis of different factors. The results showed that fertilizer application rate was the key to control nitrogen and phosphorus loss. Additionally, the suitable replacement ratio of organic fertilizer could further reduce the loss risk. It should be noted that the urgent demand for nutrients in crop growth should be considered to determine the timing of organic fertilizer application, and agricultural machinery should be used to assist organic fertilizer application to reduce labor output if possible. Fertilizer efficiency was the core of environmental friendliness and economic benefits of crop farming. Hence, improving fertilizer efficiency should be the guidance of fertilizer application strategy adjustment. Our suggestions on the adjustment of fertilizer application strategy in different crop systems in the study area are as follows:attention should be paid to the nitrogen, phosphorus, and potassium input ratio in paddy systems to further reduce nitrogen and phosphorus loss. Planting structure adjustment should be emphasized in vegetable systems to promote fertilizer efficiency. The strategy to satisfy both tea and orchard growth from a composite system perspective would help to build crop systems that meet the needs of green agricultural development.