Fertilizer Management Strategies Research Articles

Nutrient Cycling in Organic Field Crops in Canada and the United States

Organic farmers have identified soil fertility and weed management as the two highest research priority areas. No review exists of research on soil nutrient management in organic field crop systems. We conducted a comprehensive review to identify the principles and factors governing nutrient management, knowledge gaps, and future research needs in organic grain and other field crop systems in Canada and the United States. We compared results from research conducted in different climates, soils, and crop rotational sequences. Results indicate that (i) dual‐use cover/green manure crops and/or animal manure are the most common sources of plant available N and other nutrients in organic field crop systems; (ii) soil nutrient deficiencies can develop through sole reliance on cover/green manure crops; (iii) dependence on animal manure can lead to N and P excesses; (iv) conventional soil testing procedures may not accurately predict crop nutrient needs; (v) greater knowledge of microbial processes governing nutrient cycling is needed; and (vi) better understanding of the impact of weeds on soil fertility may create weed and nutrient management synergies. Knowledge gaps include a lack in understanding of how the soil and plant biomes influence nutrient‐use efficiency and how crop diversity and rotations impact soil fertility, sustainability, and resilience in organic field crop systems. Likewise, interactions between weeds, crops, soil fertility, and weed management strategies are poorly understood.Core Ideas Soil, climate, fertility sources, and land use impact organic nutrient management strategies. Cover/green manure crops and animal manures are used to maintain soil fertility on organic farms. Conventional soil testing may not be ideally suited to organic systems. Tracking soil nutrient temporal changes can improve comprehensive nutrient management plans. More research of how weeds and soil microbial community structure/function impact nutrient cycling and crop production is needed.

One‐Time Fertilizer Briquettes Application for Maize Production in Savanna Agroecologies of Ghana

Declining maize yields in the Guinea Savanna ecological zone of Ghana call for effective nutrient management strategies that increase maize productivity and profitability among smallholder farmers. Field trials were conducted during 2016 and 2017 in three locations in northern Ghana to evaluate the agronomic effectiveness of one‐time application of multi‐nutrient fertilizer briquettes for maize production. The treatments were: (i) farmer practice (FP); (ii) NPK fertilizer briquettes applied at the recommended N, P, and K rates (100%‐Briquette); (iii) 75%‐Briquette; (iv) modified farmer practice (MFP) with N, P, and K applied at the recommended rate (100%‐MFP); (v) 75%‐MFP; and (vi) control, with no fertilizer applied. The farmer practice involved surface broadcasting the granular N, P, and K fertilizer at the recommended rate. The MFP involved subsurface incorporation of the granular fertilizer into the soil. Across all three locations and in both years, maize grain yield resulting from the treatments followed this order: 100%‐Briquette > 100%‐MFP = 75%‐Briquette > 75%‐MFP > FP > control. Despite the greatest grain yields resulting from the 100%‐Briquette treatment, the greatest gross profit margin of 0.46 was obtained with the 75%‐Briquette treatment, followed by the 100%‐Briquette treatment (∼0.43), 100%‐MFP (∼0.39), 75%‐MFP (∼0.24), and FP (0.03). From the combined results, we conclude that the one‐time application of multi‐nutrient fertilizer briquettes could be an efficient fertilizer management strategy to increase maize yields and profitability for smallholder farmers in the Guinea Savanna zone. This presents a real strategy for improved productivity across diverse agroecologies for food security among smallholder farmers.Core Ideas One‐time application of multi‐nutrient fertilizer briquettes increased maize grain yields. High nutrient recovery efficiency of fertilizer briquettes resulted in a 25% reduction in application rates. Application of fertilizer briquettes resulted in the greatest gross profit margin of 46%. The traditional farmers’ practice of surface broadcast resulted in lowest gross profit margin of only 3%. Incorporation of fertilizers into the soil resulted in an increase of gross profit margin to 39%.

Response of Maize to Different Soil Residual Phosphorus Conditions

Large reserves of phosphorus (P) in Brazilian soils can be potentially used by crops. However, it is not well known how different tillage systems and past P fertilizer management strategies affect legacy P utilization. A trial was conducted in an Oxisol (Rhodic Haplustox) at Embrapa Cerrados, Federal District, Brazil to investigate the effects of different soil residual P conditions on maize yield. For 17 yr, annual summer crops were fertilized with 80 kg ha−1 yr−1 P2O5 in a split‐plot design consisting of eight treatments: no‐tillage system (NT) or conventional tillage (CT), fertilized with triple superphosphate (TSP) or reactive rock phosphate (RRP), applied to the crop furrow or broadcast. P fertilization was then discontinued and maize grown for 4 seasons relied on the residual soil P under NT or CT. Residual P use efficiency, calculated as a ratio between grain yield and total residual P in the soil, was greater under NT than CT, as a consequence of higher availability of P determined by Bray‐1, Mehlich‐1 and Olsen methods. Past use of RRP sustained better yields and higher residual P use efficiency, especially in NT, due to its lower solubilizing rate. P placement strategy did not change residual P use efficiency. We recommend assess amount of available P to identify sites in which residual P may sustain crop needs. Finally, the use of RRP, especially under NT, is a recommended management strategy for reducing phosphate fertilizer demand in heavily weathered soils of Central Brazil.Core Ideas No‐tillage system promotes efficient P use, especially after discontinued P supply. Due to slow solubilizing rate, reactive rock phosphate sustains better residual P availability. Fertilizer placement did not influence residual P use efficiency.

Nitrogen use efficiency of 15N urea applied to wheat based on fertiliser timing and use of inhibitors

Improving fertiliser nitrogen (N) use efficiency is essential to increase productivity and avoid environmental damage. Using a 15N mass balance approach, we investigated the effects of five N fertiliser management strategies to test the hypothesis that increasing uptake of applied N by wheat improves productivity and reduces loss of N in a semi-arid environment. Three experiments were conducted between 2012 and 2014. Treatments included urea application (50 kg N/ha) at sowing with and without nitrification inhibitor (3,4-dimethylpyrazole phosphate, DMPP) and surface broadcast with and without urease inhibitor (n-butyl thiophosphoric triamide, NBPT) at the end of tillering plus an unfertilised control. It was found that deferring fertiliser application until the end of tillering decreased losses of fertiliser N (35–52%) through increasing uptake by the crop and or recovery in the soil at harvest, while maintaining yield except when rainfall following application was low. In this case, deferring application reduced fertiliser uptake (− 71%) and grain yield (− 18%) and increased recovery of N in the soil (+ 121%). Use of DMPP or NBPT reduced N loss where seasonal conditions were conducive to denitrification during winter (DMPP) and volatilisation or denitrification later in the season (NBPT). Their effect on grain yield was less significant; DMPP increased yield (+ 3–31%) in all years and NBPT increased yield (+ 7–11%) in 2 of 3 years compared to unamended urea. The majority of crop N uptake was supplied from soil reserves and as a result, crop recovery of applied N was not strongly related to grain yield response.

Current status of nitrogen and phosphorus losses and related factors in Chinese paddy fields: A review

Rice is one of the main crops in China. Therefore, it is important to understand the current status and influencing factors of nitrogen and phosphorus losses from paddy fields in China, which would facilitate assessing the potential of chemical fertilizer reduction in different rice cultivating regions. We summarized the current knowledge on nitrogen and phosphorus losses from surface runoff in major rice cultivating areas in China, as well as their influencing factors, such as rainfall, planting pattern, cultivation techniques, fertilization management, water management strategies, etc. The total nitrogen (TN) and total phosphorus (TP) losses from runoff in six major rice cropping areas ranged from 5.09 to 21.32 and 0.70 to 3.22 kg·hm-2, respectively. The highest losses of TN and TP were the South China double rice cropping area. The TN runoff losses were the lowest in the North China single rice cropping area, while the lowest TP runoff losses occurred in plateau single and double rice cropping area of the Southwest China. The peaks of TN and TP in surface water of paddy fields were generally higher than those of the runoff water based on farmers' conventional fertilization in different rice cropping areas. The peak period of nitrogen and phosphorus losses was in a week after rice fertilization. There could be a potential of 20% reduction of nitrogen and phospho-rus for farmers' conventional fertilization compared with the optimized fertilization. Among all the factors, rainfall and fertilization management were the main ones affecting the runoff losses of nitrogen and phosphorus in paddy fields. Fertilization management and water management strategies were the mostly controllable, including reduction of fertilizers, application of new fertilizers, replacement of chemical fertilizers by organic fertilizers, water-saving irrigation, etc. Overall, the risk of nitrogen and phosphorus losses in paddy fields was more prominent in the Southern China than in any other areas of China. Rice cultivation should be carried out in a more resource-efficient way to reduce nutrient loss. Future research should focus on non-point source pollution monitoring of paddy fields, nitrogen and phosphorus losses risk assessment, nitrogen and phosphorus losses characteristics and mechanisms, and new technologies for reducing chemical fertilization inputs and environmental risks.

Evaluation of N fertilization management strategies for increasing crop yields and nitrogen use efficiency in furrow-irrigated maize–wheat system under permanent raised bed planting

ABSTRACT Information on the effect of N management on crop yields and N use efficiency (NUE) under furrow irrigations is scarce for conservation agriculture (CA)-based annual maize–wheat (MW) system in South Asia. A 2-year (2013–2015) field experiment was conducted to evaluate the effects of residue management in main plots and combinations of two rates and three methods of N fertilizer application plus no N control treatment in subplots on the yield, N uptake and NUE of permanent raised bed (PB) MW system in north-western India. Residue retained on surface significantly increased grain yields by 7.7% and 4.3% in maize and wheat compared to no residue, respectively. Results showed that while uniformly broadcast method (B) required 120 kg N ha−1, similar maize and wheat yields can be achieved with 90 kg N ha−1 using deep placement on beds (DB) thereby saving 30 kg N ha−1. DB increased maize yield by 5.4% and 10.9% compared with DF and B, respectively. In wheat, DB and DF significantly increased grain yield by 4–7% compared to B. At 120 kg N ha−1, NUE of 61% and 74% with B was increased to 73% and 98% with DB in wheat and maize, respectively.

Improving Phosphorus Use Efficiency and Optimizing Phosphorus Application Rates for Maize in the Northeast Plain of China for Sustainable Agriculture

Optimizing the phosphorus (P) application rate can increase grain yield while reducing both cost and environmental impact. However, optimal P rates vary substantially when different targets such as maximum yield or maximum economic benefit are considered. The present study used field experiment conducted at 36 experiments sites for maize to determine the impact of P application levels on grain yield, plant P uptake, and P agronomy efficiency (AEP), P-derived yield benefits and private profitability, and to evaluated the agronomically (AOPR), privately (POPR), and economically (EOPR) optimal P rate at a regional scale. Four treatments were compared: No P fertilizer (P0); P rate of 45–60 kg ha−1 (LP); P rate of 90–120 kg ha−1 (MP); P rate of 135–180 kg ha−1 (HP). P application more effectively increased grain yield, reaching a peak at MP treatment. The plant P uptake in HP treatment was 37.4% higher than that in P0. The relationship between P uptake by plants (y) and P application rate (x) can be described by the equation y = −0.0003x2 + 0.1266x + 31.1 (R2 = 0.309, p < 0.01). Furthermore, grain yield (y) and plant P uptake (x) across all treatments also showed a significant polynomial function (R2 = 0.787–0.846). The MP treatment led to highest improvements in P agronomic efficiency (AEP), P-derived yield benefits (BY) and private profitability (BP) compared with those in other treatments. In addition, the average agronomically (AOPR), privately (POPR), and economically optimal P rate (EOPR) in 36 experimental sites were suggested as 127.9 kg ha−1, 110.8 kg ha−1, and 114.4 kg ha−1, which ranged from 80.6 to 211.3 kg ha−1, 78.2 to 181.8 kg ha−1, and 82.6 to 151.6 kg ha−1, respectively. Economically optimal P application (EOPR) can be recommended, because EOPR significantly reduced P application compared with AOPR, and average economically optimal yield was slightly higher compared with the average yield in the MP treatment. This study was conducive in providing a more productive, use-effective, profitable, environment-friendly P fertilizer management strategy for supporting maximized production potential and environment sustainable development.

Evaluation of fertigation technique for phosphorus application of maize in the semi-arid region of Northeast China

To determine the best phosphorus (P) fertilizer management strategy in chernozem soil in the semi-arid region of Northeast China, a field experiment under film mulched drip irrigation was conducted for two consecutive years. Five P application methods were tested, including no P fertilizer applied (P0); P fertilizer one-time basal application (P1); one fertigation one time (P2); fertigation twice (P3) and fertigation four times (P4). The shoot dry matter weight, phosphorus accumulation, yield and POlsen in soil were measured regularly during the maize growing season. The results demonstrated that P fertilizer application methods imposed significant effects on dry shoot matter, the apparent P loss, P fertilizer use efficiency and yield of maize (P < 0.05). The yield, P agrinomic efficiency and P recovery efficiency of P4 treatment were significantly higher than P1 treatment by 4.2, 39.7, and 66.4% across two year. In addition, P4 treatment significantly enhanced the shoot dry matter weight after V12 stage, post-silking P uptake and reduced the apparent P loss. In conclusion, P fertigation and a rational frequency (e.g., fertigation four times) enable to keep the maximum grain yield, the shoot dry matter, and recovery efficiency of P fertilizer (66.4%) though changing agronomic methods for efficient acquisition of P toward a sustainable and productive agricultural fertigation system.

Sustainable Production of Robusta Coffee under a Changing Climate: A 10-Year Monitoring of Fertilizer Management in Coffee Farms in Vietnam and Indonesia

Assessing and prescribing fertilizer use is critical to profitable and sustainable coffee production, and this is becoming a priority concern for the Robusta coffee industry. In this study, annual survey data of 798 farms across selected Robusta coffee-producing provinces in Vietnam and Indonesia between 2008 and 2017 were used to comparatively assess the fertilizer management strategies in these countries. Specifically, we aimed to characterize fertilizer use patterns in the key coffee-growing provinces and discuss the potential for improving nutrient management practices. Four types of chemical (NPK, super phosphate, potassium chloride and urea) and two of natural (compost and lime) fertilizers were routinely used in Vietnam. In Indonesia, NPK and urea were supplemented only with compost. Farmers in Vietnam applied unbalanced quantities of chemical fertilizers (i.e., higher rates than recommended) and at a constant rate between years whereas Indonesian farmers applied well below the recommended rates because of poor accessibility and financial support. The overuse of chemical fertilizers in Vietnam threatens the sustainability of Robusta coffee farming. Nevertheless, there is a potential for improvement in both countries in terms of nutrient management and sustainability of Robusta coffee production by adopting the best local fertilizer management practices.

Management of nitrogen fertilization to balance reducing lodging risk and increasing yield and protein content in spring wheat

Crop lodging (stem and root lodging) is one of the main constraints limiting grain yield and quality in spring wheat production, especially under high–yielding conditions. Few studies have been conducted to clarify the trade–off between grain yield and lodging resistance, and assess whether it is possible to manage lodging risk without a yield reduction penalty. Developing appropriate nitrogen (N) fertilizer management strategies for driving grain yield/quality while reducing (or at least not increasing) the risk of lodging is needed to achieve this. The risks of stem and root lodging were quantified by “safety factor” (SF) indicator, which represents the number of times a support organ can bear the self–weight moment of the organ that it is supporting. Two varieties with contrasting stature (tall vs. semi–dwarf), were tested under different timing and rates of N application strategies. The advantage of split–N (preplant plus top–dress application at the jointing stage) over equivalent preplant–only N application was not evidenced on yield, but grain protein (%) was improved by up to 7.5% without a yield penalty. The risk of lodging was increased with increasing N rates from zero to the highest N treatment, as indicated by decreasing stem safety factor SFs (–23.7%) and root safety factor SFr (–32.2%) across both years, and increasing visual lodging score (by 7–fold) in 2017. The split–N treatment N50 + 50 (50 kg N ha–1 at preplant plus 50 kg N ha–1 at jointing stage) showed a promising lodging resistance with SFs, SFr and visual lodging scores similar to the zero N treatment. Taken together, the moderate split–N application (N50 + 50) is recommended due to the relative high grain protein (%) and strong lodging resistance while sustaining a promising yield. Spring wheat was more susceptible to root lodging than to stem lodging in the specific conditions of these experiments. Additionally, breeding for and cultivation with cultivars with improved stem strength is likely to be required to counter the escalating lodging risk arising from continued yield increases.

Minimizing nutrient leaching from maize production systems in northern Ghana with one-time application of multi-nutrient fertilizer briquettes

Nutrient losses through surface runoff and leaching from agricultural lands could have negative effects on surface water and groundwater resources in northern Ghana. Nutrient management strategies that synchronize nutrient uptake with availability will increase nutrient recovery efficiency and minimize nutrient losses to the environment. From field trials conducted at three locations in northern Ghana during the 2016 and 2017 farming seasons, we evaluated the effectiveness of one-time application of multi-nutrient fertilizer briquettes in minimizing nutrient leaching losses from maize production systems. We compared six fertilization strategies: (i) farmer practice (FP); (ii) NPK fertilizer briquettes applied at the recommended N, P, and K rates (100% briquette); (iii) 75% briquette; (iv) modified farmer practice (MFP) with granular N, P, and K sources applied at the recommended rate (100% MFP); (v) 75% MFP; and (vi) Control, with no fertilizer applied. Across all locations and both seasons, maize grain yield resulting from the treatments followed this order: 100% briquette >75% briquette = 100% MFP > 75% MFP > FP > control. Concentrations of leachate N from the two briquette treatments were consistently similar to background levels throughout the sampling periods, with the FP resulting in the greatest leachate N concentrations, followed by its modifications. There were no significant treatment effects on leachate P and K concentrations. Therefore, for environmental sustainability, the one-time application of multi-nutrient fertilizer briquettes could be an ideal fertilizer management strategy for maize production in northern Ghana. In addition to the environmental benefit of decreased nutrient leaching, one-time application of multi-nutrient fertilizer briquettes could provide significant agronomic benefits of increased yields from increased nutrient retention in the soil and improved nutrient utilization by the maize plants.

Chinese consensus guidelines for breast cancer in young women: clinical practice and fertility preservation

Breast cancer in young women is a relatively common disease in China. Its clinical, pathological and genetic characteristics make the disease special. The consequences of anticancer treatments including premature menopause and impaired fertility have far-reaching impact for these women both medically and psycho-socially. Thus, specific multimodality care is paramount. To standardize the diagnosis and treatment process of breast cancer and fertility management strategy in young patients, based on the literature and relevant international guidelines, the oncology specialists and experts on reproductive medicine discuss and propose this "Chinese Consensus Guidelines for Breast Cancer in Young Women: Clinical Practice and Fertility Preservation" .

Characterization of fluvo-aquic soil phosphorus affected by long-term fertilization using solution 31P NMR spectroscopy.

Reducing the applications of mineral phosphorus (P) fertilizers and supplementing them by organic fertilizers is becoming a necessary practice in the North China Plain due to overuse of mineral P fertilizers and improper disposal of organic wastes. Knowledge is needed about how the long-term substitution of mineral fertilizers by organic fertilizers affects soil P forms in order to understand soil P transformation and crop P uptake. In this study, we used solution 31P nuclear magnetic resonance (NMR) spectroscopy to characterize P forms in fluvo-aquic soil after 26 years of different fertilization management strategies, organic compost (OM), half compost in combination with half mineral fertilizer NPK (1/2 OM), mineral fertilizer NPK (NPK), mineral fertilizer NK (NK), and an unfertilized control (CK). Results showed that the P extraction efficiency using NaOH-EDTA varied from 13.0 to 27.7% for the soils of the treatments. 31P NMR spectra indicated that the majority of P was in the form of orthophosphate for all the treatments, which constituted 64.3-83.5% of the total extracted P. The application of P fertilizers significantly increased the concentrations of orthophosphate, monoesters and diesters regardless of the P fertilization method, although the proportions of monoesters and diesters were higher in CK. The proportions and concentrations of orthophosphate significantly decreased when all mineral fertilizers were replaced by compost. There was no significant difference in the proportions and concentrations of total organic P, corrected monoesters and diesters in NaOH-EDTA extracts of soils among NPK, 1/2OM and OM treatments. Decreasing mineral P fertilizers and partly replacing them by organic fertilizer in fluvo-aquic soil might increase soil test (Olsen) P and crop P uptake through the degradation of applied organic P forms.

Assimilation of Sentinel-2 Leaf Area Index Data into a Physically-Based Crop Growth Model for Yield Estimation

Remote sensing data, crop growth models, and optimization routines constitute a toolset that can be used together to map crop yield over large areas when access to field data is limited. In this study, Leaf Area Index (LAI) data from the Copernicus Sentinel-2 satellite were combined with the Environmental Policy Integrated Climate (EPIC) model to estimate crop yield using a re-calibration data assimilation approach. The experiment was implemented for a winter wheat crop during two growing seasons (2016 and 2017) under four different fertilization management strategies. A number of field measurements were conducted spanning from LAI to biomass and crop yields. LAI showed a good correlation between the Sentinel-2 estimates and the ground measurements using non-destructive method. A correlating fit between satellite LAI curves and EPIC modelled LAI curves was also observed. The assimilation of LAI in EPIC provided an improvement in yield estimation in both years even though in 2017 strong underestimations were observed. The diverging results obtained in the two years indicated that the assimilation framework has to be tested under different environmental conditions before being applied on a larger scale with limited field data.

Seed Yield Components and Seed Quality of Oilseed Rape Are Impacted by Sulfur Fertilization and Its Interactions With Nitrogen Fertilization.

Although the impact of sulfur (S) availability on the seed yield and nutritional quality of seeds has been demonstrated, its impact coupled with nitrogen (N) availability remains poorly studied in oilseed rape. A deeper knowledge of S and N interactions on seed yield components and seed quality could improve S and N fertilization management in a sustainable manner. To address this question, our goals were to determine the effects of nine different S fertilization management strategies (i) in interaction with different levels of N fertilization and (ii) according to the timing of application (by delaying and fractionating the S inputs) on agronomic performances and components of seed yield. The impact of these various managements of S and N fertilizations was also investigated on the seed quality with a focus on the composition of SSPs (mainly represented by napins and cruciferins). Our results highlighted synergetic effects on S and N use efficiencies at optimum rates of S and N inputs and antagonistic effects at excessive rates of one of the two elements. The data indicated that adjustment of S and N fertilization may lead to high seed yield and seed protein quality in a sustainable manner, especially in the context of reductions in N inputs. Delaying S inputs improved the seed protein quality by significantly increasing the relative abundance of napin (a SSP rich in S-containing amino acids) and decreasing the level of a cruciferin at 30 kDa (a SSP with low content of S-amino acids). These observations suggest that fractionated or delayed S fertilizer inputs could provide additional insights into the development of N and S management strategies to maintain or improve seed yield and protein quality. Our results also demonstrated that the S% in seeds and the napin:30 kDa-cruciferin ratio are highly dependent on S/N fertilization in relation to S supply. In addition, we observed a strong relationship between S% in seeds and the abundance of napin as well as the napin:30 kDa-cruciferin ratio, suggesting that S% may be used as a relevant index for the determination of protein quality in seeds in terms of S-containing amino acids.

Assessing the Response of Tomato Yield, Fruit Composition, Nitrogen Absorption, and Soil Nitrogen Fractions to Different Fertilization Management Strategies in the Greenhouse

A greenhouse field experiment involving tomato (Solanum lycopersicum) was performed using different nitrogen (N) management regimes: sole application of differing rates of chemical N fertilizer (SC) (SC treatments: N0, N1, N2, and N3) and combined application of manure and chemical N fertilizer (MC) (MC treatments: MN0, MN1, MN2, and MN3). These were used to understand the relationship between comprehensive fruit composition, yield, and N fractions (soil mineral N; soil soluble organic N; soil microbial biomass N, and soil fixed ammonium) under greenhouse conditions. The results showed that the MC treatments significantly increased vitamin C and soluble sugar content compared with SC treatments. In addition, the MN2 treatment produced a high yield and had a positive effect on fruit composition. The N3 (563 kg N/ha) and MN3 (796 kg N/ha) treatments resulted in a high loss of N below the root zone (0–30 cm), consequently reducing N use efficiency. Soil mineral N, soil soluble organic N, and soil fixed ammonium tended to be higher during the first fruiting period, whereas soil microbial biomass N tended to be higher during the second fruiting period. MC treatments significantly increased the N fraction in the 0- to 30-cm soil layer; N fractions tended to be higher with the MN2 treatment. According to an optimum regression equation, soil fixed ammonium during the first fruiting period and soil microbial biomass N during the second fruiting period had a more significant influence on tomato yield and fruit composition. Overall, application MC at an appropriate rate (MN2: 608 kg N/ha) is a promising approach to achieving high yields and optimum taste, and it offers a more sustainable fertilizer management strategy compared with chemical N fertilization.

Barley yield and fertilization analysis from UAV imagery: a deep learning approach

ABSTRACTIn a world with great challenges in food security, optimising cereal production is critical. Cereals are the most important food source for human consumption. The fourth important cereal worldwide after wheat, rice and maize, is Barley, and its production strongly depends on fertilization treatments. The adoption of suitable fertilizer management strategies often results in large economic benefits to producers. However, determining optimal fertilizer doses for a specific barley variety is complex. The collection of data and their analyses can be cost prohibitive for small farmers regarding time and money. This paper introduces an approach to support producers with automatic tools for the analysis of fertilization management of barley. The proposed methodology aims to simultaneously estimate nitrogen fertilization and barley yield, from information derived from aerial RGB images captured by a UAV. Our long term goal is to provide a low-cost and wide-are-coverage solution for the estimation of barley variables that can be leveraged to increase barley yield without increasing costs. A low-cost UAV is used to capture RGB crop field images. Then, a deep convolutional neural network is used for the automated extraction of features from the images. Extracted features are feed into predictive models that estimate the variables of interest. Experimental results reveal that the proposed methodology is able to reach an accuracy above 83% when estimating nitrogen fertilization and a high correlation and low RMSE in the estimation of yield in grams. Experimental results are promising and will pave the way for the development of deep learning methods for barley analysis from aerial imagery that can be accessed by the average farmer.

Soil fertility status of agricultural land in mid-hill of Gorkha District, Nepal

Soil fertility management in agricultural land is challenging in hilly areas of Nepal. The study assesses the soil fertility status of Bari (upland) and Khet (lowland) agriculture land in Mid-hill of Gorkha district. Altogether 30 samples were collected from soil surface (0 to 20 cm) by using hand shovel in January, 2017. The soil fertility parameters like pH, organic matter (OM), total nitrogen (TN), available phosphorus (P) and available potassium (K) were analyzed using standard methods in the laboratory of Central Department of Environmental Science, Tribhuvan University. Results revealed that an average pH in upland (6.62) was higher than the lowland (5.94). Similarly, OM (3.95%) and K (36.49 kgha-1) were relatively high in upland. In addition, pH, OM and available K were significantly varied at p<0.05 in upland and lowland soils, however, there is no significant difference in TN and available P. In addition, soil nutrient index showed that status of available K in both types of land is low, while OM and TN are medium soil quality in upland and lowland soil. The use of organic fertilizer and improved farming system can maintain and sustain soil fertility for crop growth and yield. Understanding distribution of soil nutrients in the study area might be useful for planners to make effective soil fertilizer management strategies.

Assessment of Fertilizer Management Strategies Aiming to Increase Nitrogen Use Efficiency of Wheat Grown Under Conservation Agriculture

Sustainable crop production systems can be attained by using inputs efficiently and nitrogen use efficiency (NUE) parameters are indirect measurements of sustainability of production systems. The objective of this study was to investigate the effect of selected nitrogen (N) management treatments on wheat yields, grain and straw N concentration, and NUE parameters, under conservation agriculture (CA). The present study was conducted at the International Maize and Wheat Improvement Center (CIMMYT), in northwest, Mexico. Seventeen treatments were tested which included urea sources, timing, and methods of fertilizer application. Orthogonal contrasts were used to compare groups of treatments and correlation and regression analyses were used to look at the relationships between wheat yields and NUE parameters. Contrasts run to compare wheat yields or agronomic efficiency of N (AEN) performed similarly. Sources of urea or timing of fertilizer application had a significant effect on yields or AEN (p > 0.050). However, methods of application resulted in a highly significant (p < 0.0001) difference on wheat yields and agronomic efficiency of N. NUE parameters recorded in this study were average but the productivity associated to NUE levels was high. Results in this study indicate that wheat grew under non-critically limiting N supply levels, suggesting that N mineralization and reduced N losses from the soil under CA contributed to this favorable nutritional condition, thus minimizing the importance of N management practices under stable, mature CA systems.

Müllerian inhibiting substance/anti-Müllerian hormone as a fertility preservation agent.

The nascent field of oncofertility is quickly gaining traction as novel experimental treatments are being developed, driving a renewed interest in Müllerian inhibiting substance (MIS) as an ovarian fertoprotectant. MIS is unique in its mechanisms of ovarian protection by virtue of acting directly on granulosa cells of primordial follicles and for being a benign reproductive hormone, with few side effects. We will explore in this review how it may be utilized to protect the ovary from chemotherapy, or to enhance ovarian tissue cryopreservation therapy. We will also examine potential mechanisms of action of MIS across multiple cell types, as well as current limitations in our understanding of the pharmacology of recombinant MIS. The usefulness of MIS as a fertoprotectant may be dependent on the mechanisms of gonadotoxicity of each chemotherapeutic. Further investigation is needed to determine how to best deliver and combine MIS treatment to existing fertility management strategies.