Reduced Fertilizer Inputs Research Articles

Cereal–Legume Intercropping: Which Partners Are Preferred in Northwestern Europe?

To increase Europe’s self-sufficiency for protein sources, boosting plant protein production is a prerequisite. Yield variability is one of the main problems regarding the cultivation of protein crops. In this light, cereal–legume intercropping can offer a solution, as well-balanced intercropping systems are less prone to yield variations. Therefore, in this study the effects of (i) species/genotype combination, (ii) intercropping sowing densities and (iii) fertilizer regime were evaluated under Belgian (Northwestern European) conditions over three years (i.e., the 2020–2021, 2021–2022 and 2022–2023 seasons). Regarding the species combinations, winter barley x winter pea, winter wheat x winter faba bean and winter triticale x winter faba bean, it was observed that the best-performing combination varied from year to year depending on the prevailing weather conditions. A reduced sowing density (i.e., 130 seeds/m2 for the cereal partner and 20 seeds/m2 in the case of faba bean or 40 seeds/m2 in the case of pea) was sufficient to achieve competitive yields under the prevailing conditions. Inoculation with commercial Rhizobium strains did not result in an increased yield. Fertilization with one or two nitrogen fractions significantly increased the total yield thanks to a yield increase in the cereal partner; however, as a consequence, the proportion of legumes in the mixture decreased. In conclusion, it can be stated that with the investigated cereal–legume combinations, a competitive yield and qualitative protein yield can be achieved with a reduced fertilizer input.

Assessing the Response Mechanisms of Elevated CO2 Concentration on Various Forms of Nitrogen Losses in the Golden Corn Belt

AbstractNitrogen (N) loss is a significant source of water quality pollution in alluvial watersheds. However, the mechanisms linking N loss and elevated CO2 concentration (eCO2) are not well recognized. In this study, we comprehensively calibrated the SWAT model equipped with a dynamic CO2 input and response module to investigate the response mechanisms between multiform N losses and eCO2 in a representative large‐scale watershed. Results revealed nitrate loss under eCO2 exceeding 100% in some upstream zones under the SSP5‐8.5 scenario (P < 0.05) compared to the constant CO2 concentration. This was directly related to the great increase in hydrological variables, which were the carriers of N losses, and the intensive inputs of N fertilizer. Results also found that nitrate leaching was greater than the other two processes for future periods, peaking at 309.3%, as compared to the baseline period. The findings suggested reducing fertilizer inputs by 10%–20% was promising, especially for reducing nitrate loss through runoff and leaching by up to 17.7% and 12.2%. This study explored the mechanisms of increased N loss in response to eCO2 and provided scientific evidence for early warning and making decisions to improve water quality at a large watershed scale.

Promoting sustainable smallholder farming systems in China

CONTEXTHundreds of millions of smallholder farmers account for 84% of farming households globally. Owing to the limited access to knowledge and resources, smallholder farming systems under sub-optimal management are facing multiple challenges such as adverse environmental impacts and difficulties in meeting growing food demand. Although substantial advanced techniques and practices have been developed, applying these practices on the ground at a large scale remains a great challenge. OBJECTIVESThis study aims to assess the sustainability of typical soil-crop management practices in order to recommend best practice bundles. The study also deploys a farmer survey in order to identify barriers hindering the adoption of sustainable practices and propose ways to overcome these barriers. METHODSTo achieve these aims, we develop a generalizable framework combining technical innovations and social realization pathway for sustainable transformation of smallholder farming systems. We apply this framework in the North China Plain as a case study, propose target-oriented practice bundles and subsequent realization roadmaps from smallholder farmer's perspectives and interests. RESULTS AND CONCLUSIONSOur results show that nitrogen reduction has the greatest positive effect on the overall sustainability of smallholder farming systems (12–14%), followed by formula fertilizer (6–10%) and optimal crop practices (2–4%). Thus, our recommended practice bundles include reducing fertilizer inputs and optimal sowing date and rate. However, our farmer survey shows that the implementation of these recommended practices faces barriers associated with economic costs, labor requirements, and farmer's preferences and acceptance. We suggest ways to overcome these barriers, including multi-stakeholder platforms better connecting smallholders, scientists, government, and industry. SIGNIFICANCEOur framework can be amended to fit different contexts and targets, therefore it can be adopted and tweaked by other regions worldwide dominated by smallholder agriculture to promote sustainable transformation.

Combined dynamic transcriptome and flavonoid metabolome reveal the role of Mo nanoparticles in the nodulation process in soybean

Symbiotic nitrogen fixation can reduce the impact of agriculture on the environment by reducing fertilizer input. The rapid development of nanomaterials in agriculture provides a new prospect for us to improve the biological nitrogen fixation ability of leguminous crops. Molybdenum is an important component of nitrogenase, and the potential application of MoO3NPs in agriculture is largely unexplored. In this study, on the basis of verifying that MoO3NPs can improve the nitrogen fixation ability of soybean, the effects of MoO3NPs on the symbiotic nitrogen fixation process of soybean were investigated by using dynamic transcriptome and targeted metabolome techniques. Here we showed that compared with conventional molybdenum fertilizer, minute concentrations of MoO3NPs (0.01–0.1 mg kg−1) could promote soybean growth and nitrogen fixation efficiency. The nodules number, fresh nodule weight and nitrogenase activity of 0.1 mg kg−1 were increased by 17 %, 14 % and 27 %, and plant nitrogen accumulation increased by 17 %. Compared with conventional molybdenum fertilizer, MoO3NPs had a greater effect on apigenin, kaempferol and other flavonoid, and the expression of nodulation related genes such as ENOD93, F3'H. Based on WGCNA analysis, we identified a core gene GmCHS9 that was positively responsive to molybdenum and was highly expressed during MoO3NPs induced nodulation. MoO3NPs could improve the nitrogen fixation ability of soybean by promoting the secretion of flavonoids and the expression of key genes. This study provided a new perspective for the nano-strengthening strategy of nodules development and flavonoid biosynthesis by molybdenum.

Effects of management practices on the ecosystem-service multifunctionality of temperate grasslands

Human wellbeing depends on ecosystem services, highlighting the need for improving the ecosystem-service multifunctionality of food and feed production systems. We study Swiss agricultural grasslands to assess how employing and combining three widespread aspects of grassland management and their interactions can enhance 22 plot-level ecosystem service indicators, as well as ecosystem-service multifunctionality. The three management aspects we assess are i) organic production system, ii) an eco-scheme prescribing extensive management (without fertilization), and iii) harvest type (pasture vs. meadow). While organic production system and interactions between the three management aspects play a minor role, the main effects of eco-scheme and harvest type considerably shape single services. Moreover, the eco-scheme ‘extensive management’ and the harvest type ‘pasture’ enhance plot-scale ecosystem-service multifunctionality, mostly through facilitating cultural services at the expense of provisioning services. These changes in ecosystem-service supply occur mainly via changes in land-use intensity, i.e., reduced fertilizer input and harvest frequency. In conclusion, diversifying grassland management where this is currently homogeneous across farms and landscapes depicts an important first step to improve landscape-scale multifunctionality for sustainable grassland systems. To meet societal ecosystem services demand, the three studied management aspects can be systematically combined to increase ecosystem services that are in short supply.

Reduced Fertilization to Improve Sustainable Use of Resources and Preserve Postharvest Quality of Fresh-Cut Wild Rocket (Diplotaxis tenuifolia L.) in Soil-Bound and Soilless Cultivation.

Reducing fertilizer input is a goal for helping greenhouse farming to achieve higher sustainability in the production process while preserving overall crop performance and quality. Wild rocket plants were cultivated in a plastic greenhouse divided into two independent sectors, one for soil-bound (SbS) cultivation and another equipped for soilless (ScS) cultivation systems. In both SbS and ScS, the crop was subjected to treatments consisting of a high- and a low-input fertilization program (HF and LF treatment, respectively). Water use efficiency (WUE) and partial factor productivity (PFP) for nutrients (N, P, K, Ca, and Mg for ScS, and N for SbS) were measured. Rocket leaves, separated for the cultivation system and fertilization program and collected at different cuts during the growing cycle, were cold stored at 10 °C until 16 d. On each sampling day (at harvest and during storage), the sensory parameters, respiration rate, dry matter, color, electrolyte leakage, antioxidant activity, total phenols, total chlorophyll and ammonia content were evaluated. In ScS, the PFP for all nutrients supplied as fertilizers showed a significant increase with the LF treatment, with values higher than 30% recorded for N, K, and Ca. As for the postharvest performance, rocket leaves cultivated in ScS showed better qualitative traits than those cultivated in SbS, as suggested by the lower values of ammonia content and electrolyte leakage recorded at the end of storage period in samples grown in ScS. Moreover, in ScS, the data showed lower membrane damage in LF than HF rocket leaves. Finally, regarding total chlorophyll content, even if no effect of each treatment was recorded in SbS, rocket cultivated in ScS showed a better retention of this parameter by applying LF rather than HF treatment. In addition to this, a PLS model (R2 = 0.7) able to predict the cultivation system, using as a variable non-destructively measured total chlorophyll content, was implemented. Low fertilization input, both in SbS and in ScS, allowed satisfying production levels and more sustainable management of nutrients. LF treatment applied to ScS also had in positive effects on the postharvest quality of fresh-cut rocket leaves.

Utilization of Stenotrophomonas koreensis and Bacillus amyloliquefaciens for Improving Growth, Reducing Nitrogen Fertilization and Controlling Bipolaris sorokiniana in Wheat

Wheat (<em>Triticum aestivum</em> L.), a vital cereal, faces significant challenges from common root rot and spot blotch diseases caused by <em>Bipolaris sorokiniana</em>. This study aimed to explore the potential of plant growth promoting rhizobacteria (PGPR) to enhance wheat growth, reduce fertilizer input, and combat <em>Bipolaris </em>diseases. Two PGPR isolates, selected for their superior antagonistic properties, were identified as <em>Stenotrophomonas koreensis</em> RB11 and <em>Bacillus amyloliquefaciens </em>RB12. These PGPR strains displayed multiple plant growth promoting and biocontrol attributes, including phosphate solubilization, indole-3-acetic acid production, nitrogen fixation and antagonism against <em>B. sorokiniana</em> and other fungi. Wheat seed priming with the PGPR significantly improved germination, plant growth, nutrient content and biomass carbon accumulation in the rhizosphere soil. Importantly, the application of RB11 and RB12 allowed for a 25% and 50% reduction in nitrogen fertilizer usage, respectively, without compromising the yield. RB11 and RB12 also demonstrated potent inhibitory effects on <em>B. sorokiniana</em> conidial germination and significantly controlled common root rot and spot blotch in wheat, similar to those observed with the fungicide Protaf 250EC. Overall, this study underscores the multifaceted roles of <em>S. koreensis</em> RB11 and <em>B. amyloliquefaciens</em> RB12 in promoting wheat growth, reducing fertilizer inputs and effectively suppressing wheat pathogens. These findings contribute to the development of PGPR-based strategies for sustainable crop production and disease control.

Mapping current and future habitat suitability of Azolla spp., a biofertilizer for small-scale rice farming in Africa.

How do we feed the expanding human population without excessive resource depletion or environmental degradation? Recycling and recapturing nutrients could alleviate these challenges, especially if these strategies are robust to climate change. Co-cultivating rice with Azolla spp. in Asia has demonstrated high yields with reduced fertilizer inputs because Azolla fixes atmospheric nitrogen, limits nitrogen volatilization, recaptures and releases other nutrients, and suppresses weeds. While Azolla is distributed in Africa, this approach has not been widely implemented in African rice-farming. Characterizing the suitability of Azolla is critical in evaluating the potential for Azolla-rice in Africa. To do so, we synthesized 189 field and greenhouse studies from around the world that quantified temperature-dependent growth of A. pinnata and A. filiculoides and developed present and future climate suitability maps at the continental scale using mean temperatures under two Representative Concentration Pathways. Currently, most of Africa is suitable for Azolla with slight differences in regional suitability for each species. We project little change in the continent-wide suitability for both species, but anticipate a regional decline, particularly for A. filiculoides in the Sahel. Collaborating with farmers to validate these projections, evaluate the costs and benefits of Azolla-rice, and facilitate adoption of viable strategies can facilitate equitable food systems that also empower African farmers.

Optimized fertilization based on fallow season precipitation and the Nutrient Expert system for dryland wheat reduced environmental risks and increased economic benefits

In drylands, optimized management of fertilization based on precipitation is very important to reduce fertilizer inputs and environmental risks and improve crop yield and benefits. Based on a four-year winter wheat experiment with two treatments (FP, farmers’ practices; NE, Nutrient Expert system recommendation) at nine counties of the Chinese Loess Plateau, we determined the effects of NE on wheat yield, environmental risks, and economic benefits under three precipitation year types (dry, normal, and wet) and recommended optimized N fertilization. The results showed that the NE treatment reduced N and P fertilizer input rates by 21.7% and 50.0%, respectively, Nr losses by 30.1% and GHG emissions by 21.6%, but it did not affect wheat grain yield compared to the FP treatment. There were no significant differences in N and P input rates among the three precipitation year types, but higher grain yield and partial factor productivity of N and P fertilizers were found in wet years in the NE treatment. Additionally, soil nitrate N residues in the 0–100 cm soil layers were ordered in wet years < normal years < dry years. Based on the NE system, the optimized N fertilization method could further reduce the N fertilizer rate by 16.6% and 62.5%, Nr losses by 20% and 68%, and GHG emissions by 1.7% and 47.8% in normal and dry years, respectively, but could increase economic benefits by 3.3% and 5.6%, suggesting that optimized fertilization based on fallow season precipitation can result in multiple benefits for agriculture and the environment.

Will the endophytic fungus Phomopsis liquidambari increase N-mineralization in maize soil?

Endophytes can be developed into biocontrol agents and can be fungi, bacteria, or archaea that live inside plant tissues without causing symptoms of disease. Phomopsis liquidambari is an endophytic fungus that plays an important ecosystem role as a biofertilizer by helping its host obtain soil nitrogen. How this fungus impacts N mineralization and microbial communities is little known. Our understanding of soil nutrient transformations and soil-plant-microbe interactions in Phomopsis liquidambari-crop versus conventional crop systems is incomplete. This study provided a better understanding of the effect of Phomopsis liquidambari on nitrogen mineralization and investigated the interaction between P. liquidambari and nitrogen, which in turn will be helpful to the farmer in reducing the required amount of soil N fertilizer. This change in N availability in maize soil will have significant implications for soil productivity and plant N utilization, especially in N-limited soils, and significantly reduce the required amount of soil N fertilizer. The effect of P. liquidambari on N mineralization in maize soil was investigated by treating it with four levels of N (urea) at rates of 0, 1.25, 2.5, and 3.75 g of nitrogen. N-mineralization was determined by the anaerobic incubation method. Were stored for 7 days in an incubator at a constant 37 C. A colorimetric microplate procedure was used for NH4+-N analysis. A significant increase in the available NH4+-N contents was reported in soil maize (Zea mays L.) inoculated with P. liquidambari, which increased by 80%. A significant increase in N-mineralization was observed under all N conditions. This work highlighted the importance of the fungal endophyte for soil N-mineralization with lower N input. Using this fungal agent will almost certainly help reduce fertilizer input.

Increasing lettuce productivity through Starter Solution Technology (SST)

Starter Solution Technology (SST), which is a highly concentrated liquid fertilizer, has been researched by AVRDC the World Vegetable Center. SST is a technological innovation to reduce fertilizer input while also increasing the efficiency of fertilizer use and crop productivity. The purpose of this research is to apply starter solution technology which is an efficient way of using fertilizer in order to increase lettuce production. The research was conducted in Tawangargo Village, Karangploso District, Malang Regency from July to September 2022. There were 10 treatments, including P1 = NPK 3 gr/plant, T2 = NPK 2 gr/plant, P3 = 1.5 g/plant, P4 = 1 g /plant, P5 = 0.5 g/plant, P6 = NPK 3 g/plant + SST, P2 = NPK 2 gr/plant + SST, P3 = 1.5 g/plant + SST, P4 = 1 g/plant + SST, P5 = 0.5 g/plant + SST. The results showed that the use of SST technology was able to produce better growth and yield and was able to reduce the use of inorganic fertilizers by more than 60% from the current level of fertilizer use without significant reduction in yield. Adding fertilizer to the starter treatment reduced lettuce production.

Regional-Scale Virtual Nitrogen, Phosphorus, and Potassium Factors of Potato Production in China

Improving yield in potato production with minimal environmental impact is of great significance for China’s potato staple food policy. Previous research has been limited by the absence of regional-scale parameters to evaluate the environmental costs of regional potato production. To address this gap, we utilized the input–output analysis method to offer a thorough estimation of nitrogen (N), phosphorus (P), and potassium (K) inputs and outputs in the potato production stage at a regional scale, leveraging a meta-analysis dataset from plenty of the literature. On this basis, we calculated the virtual N, P, and K factors (VNFs, VPFs, and VKFs) for different potato production regions, under both conventional and optimal management practices. China’s potato production suffered from excessive N and P inputs, while K inputs remained insufficient. Significant spatial heterogeneities were observed for the VNFs, VPFs, and VKFs across different potato production regions. Northeast China and northwest China emerged as the most suitable potato cultivation regions because they demonstrated high potato yields with relatively low inputs and, consequently, lower VNFs and VPFs. Southwest China was the most vital region where targeted efforts could lead to reducing VNF and VPF, thus significantly mitigating environmental N and P losses. In addition to reducing fertilizer inputs, site-specific and whole optimization measures are proposed to lower the environmental costs and promote the sustainable development of potato production.

Cannabis Hunger Games: nutrient stress induction in flowering stage - impact of organic and mineral fertilizer levels on biomass, cannabidiol (CBD) yield and nutrient use efficiency.

Indoor medicinal cannabis cultivation systems enable year-round cultivation and better control of growing factors, however, such systems are energy and resource intensive. Nutrient deprivation during flowering can trigger nutrient translocation and modulate the production of cannabinoids, which might increase agronomic nutrient use efficiency, and thus, a more sustainable use of fertilizers. This experiment compares two fertilizer types (mineral and organic) applied in three dilutions (80, 160 and 240 mg N L-1) to evaluate the effect of nutrient deprivation during flowering on biomass, Cannabidiol (CBD) yield and nutrient use efficiency of N, P and K. This is the first study showing the potential to reduce fertilizer input while maintaining CBD yield of medicinal cannabis. Under nutrient stress, inflorescence yield was significantly lower at the final harvest, however, this was compensated by a higher CBD concentration, resulting in 95% of CBD yield using one-third less fertilizer. The higher nutrient use efficiency of N, P, and K in nutrient-deprived plants was achieved by a larger mobilization and translocation of nutrients increasing the utilization efficiency of acquired nutrients. The agronomic nutrient use efficiency of CBD yield - for N and K - increased 34% for the organic fertilizers and 72% for the mineral fertilizers comparing the dilution with one-third less nutrients (160) with the highest nutrient concentration (240). Differences in CBD yield between fertilizer types occurred only at the final harvest indicating limitations in nutrient uptake due to nutrient forms in the organic fertilizer. Our results showed a lower acquisition and utilization efficiency for the organic fertilizer, proposing the necessity to improve either the timing of bio-availability of organic fertilizers or the use of soil amendments.

Climate change and agricultural ecosystem: Challenges and microbial interventions for mitigation

Climate change has an impact on agricultural activity because of its direct reliance on climate change. There are two types of relationships between agriculture and climate change, and they are extremely important, particularly for developing and underdeveloped or low-income countries, which rely heavily on agriculture for subsistence and lack adaptation infrastructure when compared to developed countries. Geographically high-latitude places that already have low temperatures might benefit from a prolonged growing season when temperatures rise due to climate change. GHG emissions such as carbon dioxide, nitrous oxide, and methane have an impact on agricultural lands. Gases have an impact on climate through emitting greenhouse gases. Emissions are mostly caused by tillage operations, fossil fuels, fertilized agricultural soils, and farm animal waste, and have a significant impact on the agriculture industry. Agriculture, on the other hand, might be a solution to climate change by lowering emissions and extensively implementing mitigation and adaptation measures. Best management approaches such as use of microbial inoculants to reduce fertilizer inputs, carbon sequestration and methane oxidation has potential to reduce greenhouse gases from agro-ecosystem.

Plant and soil N of different winter cover crops as green manure for subsequent organic white cabbage

Leguminous cover crops used as green manures can reduce fertilizer inputs by supplying nitrogen (N) via mineralization of incorporated N-rich biomass derived from biological N2 fixation. In a multi-year trial at three locations in Germany, the effects of leguminous, non-leguminous and mixed green manure crops on the yield of the subsequent cash crop white cabbage (Brassica oleracea convar. capitata var. alba) were investigated. The winter cover crop treatments were forage rye (Secale cereale L.), a mixture of forage rye with winter Hungarian vetch (Vicia pannonica Crantz), sole-cropped winter Hungarian vetch, winter pea (Pisum sativum L.), and winter faba bean (Vicia faba L.) with bare soil as a control. Sole-cropped legumes showed higher marketable cabbage head yields (head weight > 1.0 kg) compared to the other cover crop treatments, with 25.5, 25.9 and 28.1 Mg ha− 1 for vetch, pea and faba bean, respectively. The aboveground biomass of the legume winter cover crop treatments had higher N offtakes with 185, 177 and 159 kg N ha− 1 for vetch, pea and faba bean, respectively, with significantly lower carbon (C)/N ratios compared to rye and rye with vetch. The constant C/N ratio of the aboveground biomass of leguminous cover crops throughout the growing period indicates that the optimum incorporation date to achieve high N mineralization rates is less time dependent in leguminous compared to non-leguminous cover crops. The results of the present study show that leguminous winter cover crops do not reduce the soil N availability for a succeeding high N demanding cabbage crop resulting in yields comparable to agricultural practice without winter cover crops.

Dry‐matter production and botanical composition of multispecies and perennial ryegrass swards under varying defoliation management

AbstractMultispecies swards, comprised of different plant functional groups have comparable production potential to high N input L. perenne swards at reduced N when legumes are included. However, information on the appropriate management of multispecies swards is limited. The effect of differing management practices on the herbage dry‐matter (DM) production and botanical composition of different sward types was investigated using a 3 × 2 × 2 factorial design plot experiment. The experiment consisted of three sward types: L. perenne‐only receiving (LP; 250 kg N ha−1 a−1); L. perenne‐Trifolium repens (LP‐TR); multispecies sward containing L. perenne, Phleum pratense, Trifolium repens, Trifolium pratense, Plantago lanceolata and Cichorium intybus (MSS). LP‐TR and MSS received 90 kg N ha−1 a−1. Harvesting of plot herbage took place every 21 or 28 days to a defoliation height of 4 or 6 cm, over two growing seasons (March to November 2020 and 2021 inclusive). Annual herbage produced by both LP and LP‐TR was not significantly affected by defoliation frequency. However, MSS produced 1923 kg DM ha−1 a−1 more herbage when harvested less frequently. Unsown species contributed significantly less to the herbage DM of MSS compared to LP and LP‐TR and remained similar in 2020 and 2021, whereas the contribution of unsown species to herbage DM increased in LP and LP‐TR from 2020 to 2021, with noxious species more associated with LP and LP‐TR than MSS. Results demonstrate the role of multispecies swards in improving the sustainability of grass‐based agricultural systems in an environment of reduced fertilizer inputs.

Understanding barriers to adoption of sustainable nitrogen management practices in California

Achieving sustainability in agricultural nitrogen (N) management relies on farmers’ decisions to reduce fertilizer inputs and adopt conservation management practices. Understanding the drivers and barriers to farmers’ adoption of improved N management practices is critical to developing effective management and policy approaches on this intractable challenge. Existing research on farmer behavior has assumed that any barrier to adoption will result in lower practice adoption rates, without fully understanding how barriers may vary across different management practices, farm and farmer types, and stages of adoption. By leveraging two farmer survey data sets (total <i>n</i> &gt; 1,900), this study diagnoses key barriers to adoption across 11 different N management practices and a large diversity of farmer and farm types across the California Central Valley. We find resource constraints, technical knowledge, and uncertainty emerge as key barrier types that differentially affect farmers at various stages of adoption. On a practice-by-practice basis, uncertainty barriers appear greatest for nonadopters of a practice, whereas practice adopters are more likely to report resource barriers. Across management practices at the farm level, farmers with higher self-reported conservation orientations are more likely to report being affected by all barrier types, as compared to their peers with lower self-reported conservation orientations. Our findings demonstrate that barriers to adoption are more complex than simply the factors that predict lower adoption, as both adopters and nonadopters experience barriers. Furthermore, factors that typically predict higher adoption, such as conservation motivation, do not insulate a farmer from facing barriers to adoption. We consider how adopters are likely to go through a learning process while moving from considering to fully implementing a new practice, during which different barriers to behavior change may be encountered. We argue that interventions intended to motivate farmer adoption of improved management practices need to take more nuanced approaches to understanding how barriers to adoption are likely to vary across stages of adoption, farm and farmer type, and specific management practices.

Potato growth, yield and quality affected by calcium and nitrogen (CaN) compound fertilizers on andisol soil type in Lembang

The use of artificial chemical fertilizers that are very intensive and not in accordance with the availability of soil nutrients, has a negative impact on decreasing agricultural soil fertility and vegetable productivity. The aim of this experiment was to obtain an effective and efficient dose of compound fertilizer (Ca and N) for potato plants in Andisol soil type, Lembang. The experiment was carried out at Margahayu Experimental Field of Indonesian Vegetable Research Institute (IVEGRI) (1250 m asl), from June to November 2021. A randomized block design was used with 8 treatments and 4 replications. The treatments consisted of without N fertilizer, standard N single fertilizer, and 6 doses of compound fertilizer (33% Ca and 17% N). The results showed that, in general, CaN compound fertilizers increase the growth of potato plants. The application of compound fertilizer at 75% of N standard (300 kg/ha of CaN fertilizer) was the most effective dose for fertilizing potato plants on Andisol soil type in Lembang. This dose can save the use of N by 25% with a Relative Agronomic Effectiveness (RAE) value of 140%. This study showed that the use of CaN compound fertilizers at a dose of 300 kg/ha can not only reduce fertilizer input into the soil, but also increase potato yields.

Thickness of a Compost Layer on the Distribution of Water and Nutrients in a Surface-Drip-Irrigated Sandy Soil Column

The management of crop production in a sandy soil “culture” is difficult, mainly due to its low soil-water-holding capacity, organic matter and poor fertilizer efficiency. Options to increase soil water and nutrient retention for these soils include the addition of surface mulch covers, amendment with biochar and the use of layers of a mixture of charcoal and compost material. Our objective was to measure the distribution of water and nutrients for layers of control 1 (CK1), control 2 (CK2) and compost material of different thicknesses (0.02, 0.05 and 0.10 m) buried 0.01 m from the surface in a column (0.2 m radius, 0.5 m height) filled with sand. The experiment was conducted in a greenhouse located at the Agricultural Science Training Base of Ningxia University, China. There were three replicates per treatment and one soil column per replicate. The soil columns were watered with 2 L via a surface drip emitter and 45 days later, soil samples were obtained in 0.01 m increments across the diameter and depth of 0.4 m, with a total of 12 samples per column. In each sample, we measured soil water, pH, electrical conductivity, ammonium and nitrate nitrogen and available P and K. The results showed that the distribution of water content and nutrient contents were centered on the dripper and diffused to its surroundings. Notably, the horizontal diffusion distance was smaller than that of the vertical direction. In the vertical direction, compared with control 1, adding compost changed the spatial distribution of WC and nutrients and had a greater impact on available potassium (AK) than on inorganic nitrogen (IN) and available phosphorus (AP). Compared with control 1, the composting treatment decreased the content of water in the 0–10 cm surface soil, reduced the electrical conductivity (EC) and nitrate nitrogen (NO3-N), C5 and C10 increased the available potassium. Moreover, composting treatments increased the electrical conductivity, available phosphorus, available potassium and nitrate nitrogen of the 10–30 cm substrate by 61–384%, 10–240%, 11–45% and 133–929%, respectively, when compared with control 1.The nutrients increased as the thickness of the compost interlayer increased. A principal component analysis (PCA) of the C5 and C10 treatments significantly distinguished them from control 1. A linear regression fitting analysis showed that the inorganic nitrogen, available potassium and total nutrients positively correlated with the water content and electrical conductivity of the sand. The 5 cm and 10 cm composting interlayers had a high water content and ability to conserve fertilizer for sand culture, but C10 caused an excessive accumulation of nutrients. Thus, it was concluded that a composting interlayer that was less than 5 cm reduced the base fertilizer input by 24–84%. All these results suggest that applying a composting interlayer of 5 cm could retain more suitable root zone water and fertilizer for the next crop season and provide technological support to reduce fertilizer inputs.

Achieving high yield and nitrogen agronomic efficiency by coupling wheat varieties with soil fertility

Wheat breeding has progressively increased yield potential through decades of selection, markedly increased the capacity for food production. Nitrogen (N) fertilizer is essential for wheat production and N agronomic efficiency (NAE) is commonly index used for evaluate the effects of N fertilizer on crop yield, calculated as the difference of wheat yield between N fertilizer treatment and non-N fertilizer treatment divided by the total N application rate. However, the impact of variety on NAE and its interaction with soil fertility remain unknown. Here, to clarify whether and how wheat variety contributes to NAE, and to determine if soil conditions should be considered in variety selection, we conduct a large-scale analysis of data from 12,925 field trials spanning ten years and including 229 wheat varieties, 5 N fertilizer treatments, and a range of soil fertility across China's major wheat production zones. The national average NAE was 9.57 kg kg−1, but significantly differed across regions. At both the national and regional scales, variety significantly affected NAE, and different varieties showed high variability in their performance among low, moderate, and high fertility soils. Here, superior varieties with both high yield and high NAE were identified at each soil fertility fields. The comprehensive effect of selecting regionally superior varieties, optimizing N management, and improving soil fertility could potentially decrease the yield gap by 67 %. Therefore, variety selection based on soil conditions could facilitate improved food security while reducing fertilizer inputs to alleviate environmental impacts.