Reduce Fertilizer Use Research Articles

Variation for Nitrogen Use Efficiency Traits in Wheat Under Contrasting Nitrogen Treatments in South-Eastern Europe.

Wheat cultivars differ in their response to nitrogen (N) fertilizer, both in terms of its uptake and utilization. Characterizing this variation is an important step in improving the N use efficiency (NUE) of future cultivars while maximizing production (yield) potential. In this study, we compared the agronomic performance of 48 diverse wheat cultivars released between 1936 and 2016 at low and high N input levels in field conditions to assess the relationship between NUE and its components. Agronomic trait values were significantly lower in the low N treatment, and the cultivars tested showed a significant variation for all traits (apart from the N remobilization efficiency), indicating that response is genotype-dependent, although significant genotype × environment effects were also observed. Overall, we show a varietal improvement in NUE over time of 0.33 and 0.30% year–1 at low and high N, respectively, and propose that this is driven predominantly by varietal selection for increased yield. More complete understanding of the components of these improvements will inform future targeted breeding and selection strategies to support a reduction in fertilizer use while maintaining productivity.

Mobilization of organic nitrogen and phosphorus and reduction of synthetic fertilizer usage by Ceriporia lacerata HG2011 in pepper cultivation

Overuse of synthetic fertilizers leads to soil deterioration, environmental pollution, and poor crop quality. To seek microbes that are effective in mobilizing nutrients accumulated in soils is of utmost significance to reduce fertilizer use and increase fertilizer efficiencies. Thus, the mobilization of organic nitrogen (N) and phosphorus (P) by a wood-rot fungus Ceriporia lacerata HG2011 and pepper performances in response to this fungus were investigated in the laboratory and field. The results showed that C. lacerata HG2011 grew well and produced extracellular protease and phosphatase to convert peptone into free amino acid and NH4+-N, and lecithin into soluble inorganic P in liquid culture. Similarly, NH4+-N, water soluble P and Olsen P were increased by the release of protease and phosphatase as the fungus grew on and in the sterile soil. Compared with only synthetic fertilizer treatment, pepper nutrient uptake (including N, P, and K), nutrient agronomic efficiency, and fruit yield and quality were improved by the application of synthetic fertilizers plus C. lacerata HG2011 and remained unchanged in the treatment of reduced synthetic fertilizers plus C. lacerata HG2011. The field soil that received this fungus showed the higher activities of protease and phosphatase, which lead to higher N and P availability than that without C. lacerata HG2011.Taken together, C. lacerata HG2011 mobilized organic nitrogen and phosphorus, increased pepper yield and quality, and reduced synthetic fertilizer use without yield and quality sacrifices, showing a promising new use in modern sustainable agriculture beyond medical, industrial, and environmental purposes.

More Land, Less Pollution? How Land Transfer Affects Fertilizer Application.

Reducing fertilizer use is key to curbing agricultural pollution and ensuring food safety. Land transfer enables farmers to obtain a more appropriate production scale, but its effect on the intensity of fertilizer application is not theoretically certain. On one hand, farmers with more land may adopt more scientific production methods, thus reducing the use of chemical fertilizers. On the other hand, the short-term behavior of land grantees on transferred land may increase fertilizer use intensity. This paper attempts to theoretically elucidate the specific mechanisms by which land transfer affects the intensity of fertilizer application and to verify the relationship between the two using data from fixed rural observation sites across China from 2011–2014 with the fixed-effects model and the mediating effect model. This paper concludes that (1) land transfer significantly reduces the intensity of fertilizer use; (2) land transfer increases the land size and promotes the use of machinery by farmers, but only the increase in land size further reduces the intensity of fertilizer application; (3) the effect of land transfer on fertilizer application intensity is significant only for food crops and not for cash crops, and (4) the effect of land transfer on fertilizer application intensity is most pronounced in western China, where land fragmentation is the severest and insignificant in eastern China, where agricultural modernization is more advanced.

Effect of agricultural subsidies on the use of chemical fertilizer

Agricultural subsidies lead to changes in the use of chemical fertilizer by farmers. Using data from a household survey conducted annually by the Rural Economy Research Center of the Ministry of Agriculture of China from 2014 to 2018, Control Function (CF) approach and Heteroskedasticity-based identification strategy were employed to analyze the impact of agricultural subsidies on chemical fertilizer use by rice farmers. After addressing the problem of endogeneity, we found that agricultural subsidies have a significantly negative impact on the use of chemical fertilizer. Precisely, every 100% increase in agricultural subsidies would result in an average decrease of 3.4% in chemical fertilizer use. In addition, results of heterogeneity analysis showed that agricultural subsidies had a stronger negative impact on fertilizer use as rice-planting experience increases. But the ability of rice-planting management and off-farm labor within household could reduce this negative impact. We also found that the effect of arable land productivity conservation subsidies policy was short-lived. Furthermore, based on the frame of structural equation model (SEM), the results of mediation analysis showed that agricultural machine and rice-planting area had partial mediation of 5.3% and 41%, respectively. It implied that agricultural subsidies reduced fertilizer use by promoting the adoption of agricultural techniques and expanding the planting area. In brief, agricultural subsidies had both technical effect and scale effect. But the mediating effect of household income was not significant. This study is intended to assist the concerned authority and agriculture sector to understand the positive role of agricultural subsidies in sustainable production, and provides some feasible policy proposals.

Nanobubbles promote nutrient utilization and plant growth in rice by upregulating nutrient uptake genes and stimulating growth hormone production

Excessive application of chemical fertilizers can lead to serious environmental problems. In this study, we explored the use of nanobubble water for irrigation of crop rice as a means of reducing fertilizer use. The effect of nanobubbles on plant growth and nutrient uptake was evaluated in the laboratory, while crop yield and the efficiency of fertilizer use were evaluated in a field study. The laboratory experiments indicated that nanobubbles significantly improve plant height and root length in rice seedlings. Nanobubble treatment stimulated synthesis of the growth hormone gibberellin and upregulated the plant nutrient absorption genes OsBT, PiT-1 and SKOR, resulting in increased nutrient uptake and utilization by the roots. The field experiments verified the laboratory observations, showing that nanobubble treatment significantly increases rice yield by almost 8% when using similar levels of fertilizer as controls. Moreover, the same yield as controls was achieved with approximately 25% less fertilizer. As well as their impact on growth hormones and nutrient absorption genes, nanobubbles, due to hydrophobic and surface charge properties, enhance the release and absorption of soil nutrients, thereby reducing fertilizer demand. Overall, this study highlights a new and sustainable water irrigation strategy for enhancing crop yield and reducing chemical fertilizer waste.

Sustained rice yields and decreased N runoff in a rice-wheat cropping system by replacing wheat with Chinese milk vetch and sharply reducing fertilizer use

Pollution from the paddy fields has posed a threat to surface water quality, and the reactive N in runoff has been recognized as the dominant contributor. In the rice-wheat systems of eastern China, replacing wheat (Triticum aestivum) with Chinese milk vetch (CMV) (Astragalus sinicus) is known to reduce total fertilizer N use and associated N losses during winter; however, the function of the rice-CMV system in controlling the N runoff loss was overlooked during the summer rice-growing season. Over 6 years, we monitored soil mineral N, plant N accumulation, rice grain yield, N agronomic efficiency (AEN), and N runoff in rice-CMV fertilizer N rate-response experiments and made comparisons with the conventional N inputs in rice-wheat rotation. Aboveground CMV residues added 65–116 kg N ha−1 yr−1; therefore, by adjusting the fertilizer time, the rice in this system required 44–56% less N fertilizer to produce rice yields equivalent to the 270 kg N ha−1 (district average, C270) used in the rice-wheat system. In all fertilizer N application treatments, 120 kg ha−1 seemed to be the threshold that ensured the soil N supply, the N accumulation at rice critical stages, and consequently, the current level rice yield. The corresponding runoff N averaged 9.3 kg ha−1 season−1, which was 51.8% less than that in C270 (19.3 kg ha−1 season−1). Cumulative N runoff (total N and NH4+-N) correlated strongly with fertilizer N input for any single year (sample size = 108, P < 0.01). Application of 30–120 kg fertilizer N ha−1 gave an equivalent AEN, which indicated that the integration of CMV and fertilizer N could increase the agronomic efficiency of N fertilizer applied to the rice. Rotating paddy rice with CMV instead of wheat, together with the suitable adjustment of N fertilizer, could sustain rice yield and gain the utmost environmental benefits from rice-based agroecosystems.

Wheat-Paddy Straw Biochar: An Ecological Solution of Stubble Burning in the Agroecosystems of Punjab and Haryana Region, India, A Synthesis

The Rice-Wheat cropping system (RWS) is the predominant agricultural system in northern India, especially in Punjab and Haryana. About 90% of agricultural land in Punjab and Haryana is indulged in the intensive RWS cropping system. The major constraint in this system is the short time interval between rice harvesting and the sowing of wheat. The preparation of the field for the wheat crop requires the removal of stubble, and farmers burn the stubble to get rid of it as there is a lack of any other proper management strategy or alternative use of stubble. Stubble burning is a significant source of pollutants causing severe damage to human health and the environment. The appropriate stubble management could provide immense economic benefits to the farmers and guard the environment against pollution. There is a dire need for alternative solutions to stubble burning. Some alternative management practices include the direct incorporation of the stubble into the soil, stubble as fuel, raw material for pulp and paper industries, or biomass for biofuel production. Since biochar is an effective tool for the utilization of stubble into a carbon-rich source, it can further be utilized in the agroecosystems because of its potential to improve soil fertility, enhance soil carbon, and reduce fertilizer use efficiency and enhance agricultural productivity. Thus, biochar, with its immense benefits, helps in soil conditioning and is an excellent means of carbon stabilization. The stable aromatic structure of carbon is resistant to chemical processes such as oxidation to CO2 or reduction to methane, making it a suitable means to act as a long-term carbon sink. We infer that biochar as an eco-friendly answer for this issue is an exceptionally viable soil conditioner that directly influences soil carbon, soil quality, crop production and food security, promoting economic and ecological benefits.

Petunia Performance Under Application of Animal-Based Protein Hydrolysates: Effects on Visual Quality, Biomass, Nutrient Content, Root Morphology, and Gas Exchange.

Sustainable plant production practices have been implemented to reduce the use of synthetic fertilizers and other agrochemicals. One way to reduce fertilizer use without negatively impacting plant nutrition is to enhance crop uptake of nutrients with biostimulants. As the effectiveness of a biostimulant can depend on the origin, species, dose, and application method, the aim of this research was to evaluate the effect of a commercial animal-based protein hydrolysate (PH) biostimulant on the visual quality, biomass, macronutrient content, root morphology, and leaf gas exchange of a petunia (Petunia × hybrida Hort. “red”) under preharvest conditions. Two treatments were compared: (a) three doses of an animal-based PH biostimulant: 0 (D0 = control), 0.1 (D0.1 = normal), and 0.2 g L–1 (D0.2 = high); (b) two biostimulant application methods: foliar spray and root drenching. The dose × method interaction effect of PH biostimulant on the plants was significant in terms of quality grade and fresh and dry biomass. The high dose applied as foliar spray produced petunias with extra-grade visual quality (number of flowers per plant 161, number of leaves per plant 450, and leaf area per plant 1,487 cm2) and a total aboveground dry weight of 35 g, shoots (+91%), flowers (+230%), and leaf fresh weight (+71%). P and K contents were higher than in untreated petunias, when plants were grown with D0.2 and foliar spray. With foliar spray at the two doses, SPAD showed a linear increase (+21.6 and +41.0%) with respect to untreated plants. The dose × method interaction effect of biostimulant application was significant for root length, projected and total root surface area, and number of root tips, forks, and crossings. Concerning leaf gas exchange parameters, applying the biostimulant at both doses as foliar spray resulted in a significant improvement in net photosynthesis (D0.1: 22.9 μmol CO2 m–2 s–1 and D0.2: 22.4 μmol CO2 m–2 s–1) and stomatal conductance (D0.1: 0.42 mmol H2O m–2 s–1 and D0.2: 0.39 mmol H2O m–2 s–1) compared to control. These results indicate that application of PH biostimulant at 0.2 g L–1 as foliar spray helped to achieve extra-grade plants and that this practice can be exploited in sustainable greenhouse conditions for commercial production of petunia.

Vegetation restoration and agricultural management to mitigate nitrogen pollution in the surface waters of the Dan River, China.

Non-point source pollution in rivers is an important factor affecting water quality. Quantifying the load of non-point source pollutants in the water and implementing improvement measures are critical for guaranteeing drinking water quality. In this study, the Dan River watershed, which is an important water source for Beijing, was investigated. Through a combination of water sampling and numerical simulations, the temporal and spatial distributions of nitrate nitrogen (NO3--N) and ammoniacal nitrogen (NH4+-N) loads in the watershed were determined, and the effects of vegetation restoration and agricultural management on reducing nitrogen pollution in the river were predicted. The NO3--N and NH4+-N loads in the watershed were higher during the wet season (July-September), accounting for more than 50% of the annual nitrogen output. The Soil and Water Assessment Tool (SWAT) was used to simulate the nitrogen load in the watershed. Pollution from nitrogen loading was serious in the lower reaches of the river; however, vegetation restoration can reduce the nitrogen output. Through scenario simulations, we found that an increase in forestland in the watershed would reduce the NO3--N and NH4+-N loads. The nitrate and NH4+-N loads in the watershed also decreased with reduced fertilizer use and reduced irrigation application in the watershed. Thus, reasonable land planning and agricultural management measures can effectively reduce nitrogen loss, which is an effective way to control non-point source pollution in watersheds and ensure river water quality.

Responses of soil organic carbon and crop yields to 33-year mineral fertilizer and straw additions under different tillage systems

Decline in soil organic carbon (SOC) is one of the most important causes of agricultural ecosystem degradation and food insecurity. Multiple agricultural management practices, such as fertilization and straw additions, affect cropland SOC; however, long-term effects of these practices remain ambiguous. In this study, we evaluated how mineral fertilizers, straw additions, and different tillage methods affected SOC and crop yields in a long-term field experiment (1985–2017) in the North China Plain (NCP). Nine treatments consisting of different tillage methods (CT:conventional tillage; NT: no-tillage) combined with applications of inorganic N (N0, N1 and N2: 0 kg, 225 kg and 375 kg urea-N ha−1 yr−1), inorganic P (P0, P1 and P2: 0 kg, 75 kg and 150 kg P2O5 ha−1 yr−1) and straw (S0, S1 and S2: 0 kg, 2250 kg, and 4500 kg ha−1 yr−1) were established. CT-N0-P0-S0 was the control treatment. In all treatments, the SOC content increased rapidly over the first 15 years, which was mainly due to the fact that these plots were wastelands before. The SOC content of treatments with straw additions generally increased faster than treatments without straw additions. Nutrient additions and conventional tillage increased crop yields whereas straw additions had variable effects, with highest crop yields in the CT-N2-P2-S2 treatment. Long-term applications of mineral fertilizer and straw significantly affected SOC and yields (P < 0.0001). Straw additions contributed more than nutrient additions to the explained variance of SOC (19.7 %). P and N contributed most to the total explained variance of wheat yields (43.2 % and 40.9 %, respectively) and maize yields (30.5 % and 38.7 %, respectively). The climate accounted for 23.8 % of the total explained variance of maize yields, however, it contributed only 1.1 % for wheat yields (P = 0.0064). In addition, crop yields were positively correlated with SOC levels. This means that long-term applications of straw can feasibly improve SOC and crop yields, which can satisfy the economic needs of farmers and can also benefit the environment. CT-N1-P1-S2 was eventually identified as the optimal treatment to preserve soil quality and reduce fertilizer use, thereby maintaining the sustainable development of the wheat-maize agricultural system in NCP.

Customized Fertilizers- An Artefact in Indian Agriculture: A Review

Indian agriculture is suffering from low crop productivity and poor sustainability as its land suffers from varying degrees of soil fertility depletion. There exists a wide gap between amount of nutrients removed by crops and added through fertilizers resulting in reduced yields is due to mineral deficiency. Besides, there are issues of poor fertilizer response and reduced fertilizer use efficiency. Therefore, the holistic approach should be soil-climate-crop specific. It is essential to supply both macro and micronutrients to cater the needs of the crop. As Indian soils are deficit in supplying nutrients especially nitrogen and zinc, customized fertilizer is one option, being a multi-nutrient carrier of both macro and micro nutrients, is tailored to meet the region, soil, crop specific needs designed through specialised smart fertilizer technology, manufactured through systematic granulation process. These, customized fertilizer boost crop yields and arrest soil fertility deterioration over long run in a sustainable manner.

Spatial analysis of factors affecting fertilizer use efficiency in China: an empirical study based on geographical weighted regression model.

Improving fertilizer use efficiency (FUE) is an effective means to reduce fertilizer use and environmental contamination. Few studies have considered spatial effects of FUE and its determinants. This paper calculates the FUE of agricultural production by adopting panel data on 31 provinces in China from 2007 to 2017 using a stochastic frontier method and discusses the spatial distribution and characteristics. Furthermore, the geographical weighted regression (GWR) model is employed to examine the spatial impact of education level, non-agricultural employment ratio, disaster ratio, and farmers' income on FUE and reveal the spatial dispersion and agglomeration effect of different provinces in 2007, 2010, 2013, 2015, and 2017. The results show that the average FUE in China is 0.747 and has a significant decreasing trend, and FUE has a significant regional difference and spatial positive correlation in different provinces. Non-agricultural employment ratio is the most leading factor for increasing FUE for all provinces in studied years, and its influence degree shows a decreasing trend from southeastern to northwestern in each year. The different agricultural industry development modes, planting structure adjustment, and policy incentive systems for increasing non-agricultural employment ratio should be developed for different regions. Farmers' income has a significant negative impact on FUE, but the influence degree decreases annually, indicating that improving income to higher than turning point of the environmental Kuznets curve plays a critical role in improving FUE. The influence of education level on FUE is positive but relatively weak, and the influence degree declines from the western to eastern areas. It should strengthen the exploration of scientific and rational education and a training policy system to improve the educational level in different regions on the basis of local characteristics. Disaster ratio has a positive impact on FUE but is unstable. For the neighboring provinces, coordinated weather and possible disaster forecasting and release mechanism should be carried out based on the extent of the disaster.

Best Management Practices for Sustaining Agricultural Production at Choctawhatchee Watershed in Alabama, USA, in Response to Climate Change

Climate change will ultimately result in higher surface temperature and more variable precipitation, negatively affecting agricultural productivity. To sustain the agricultural production in the face of climate change, adaptive agricultural management or best management practices (BMPs) are needed. The currently practiced BMPs include crop rotation, early planting, conservation tillage, cover crops, effective fertilizer use, and so on. This research investigated the agricultural production of BMPs in response to climate change for a Hydrologic Unit Code12 sub-watershed of Choctawhatchee Watershed in Alabama, USA. The dominating soil type of this region was sandy loam and loamy sand soil. Agricultural Production Systems sIMulator and Cropping Systems Simulation Model were used to estimate the agricultural production. Representative Concentration Pathway (RCP) 4.5 and RCP8.5 that projected a temperature increase of 2.3℃ and 4.7℃ were used as climate scenarios. The research demonstrated that crop rotation had positive response to climate change. With peanuts in the rotation, a production increase of 105% was observed for cotton. There was no consistent impact on crop yields by early planting. With selected peanut-cotton rotations, 50% reduced nitrogen fertilizer use was observed to achieve comparable crop yields. In response to climate change, crop rotation with legume incorporation is thus suggested, which increased crop production and reduced fertilizer use.

An environmental and economic assessment from bioenergy production and biochar application

ContextPyrolysis has been considered an effective bioenergy technology to produce renewable energy; however, the extent to which it mitigates climate change is greatly influenced by the usage of its by-product, biochar. Bioenergy development relies on the stable supply of agricultural commodities; however, climate-induced impacts on crop yields that potentially influence the stability of biomass supply must be investigated. ObjectiveThe current study analyzed Taiwan’s bioenergy potential and the associated economic and environmental consequences. Materials and methodsA two-stage stochastic programming with a recourse model was employed to explore the biofuel and biopower production under various climate impact possibilities. Furthermore, emission offsets, such as CO2 reduction from bioenergy production and N2O reduction from biochar application were elucidated, along with changes in cropping patterns. ResultsThe results indicated that: (1) with onsite biochar application, up to 8 82 000 metric tons of CO2-equivalent emissions can be offset from the reduction of fertilizer use; (2) ethanol is less competitive, with more than 99% of bioenergy is derived from pyrolysis-based biopower; (3) net offset potential substantially decreases when N2O emissions from cropping land are considered; and (4) biochar can contribute up to 42.43–51.02% of the total emission sequestration. Discussion and conclusionThe net impact of promotion policies on social welfare depends on the size of gains obtained by producers and losses experienced by consumers, and researchers need to incorporate the heterogeneous properties of these policies to determine the country-specific effects of bioenergy development on social welfare.

Evaluating Fertilizer Use Efficiency and Spatial Correlation of Its Determinants in China: A Geographically Weighted Regression Approach.

Improving fertilizer use efficiency (FUE) is an effective means to reduce fertilizer use and environmental contamination. Few studies have considered the spatial effects of FUE and its determinants. This paper calculated the FUE of agricultural production by adopting panel data on 31 provinces in China from 2007 to 2017 using a stochastic frontier method with a heteroscedastic inefficiency term, and discussed the spatial characteristics. Further, the geographical weighted regression model (GWR) was employed to examine the spatial impact of factors on FUE and revealed the spatial dispersion and agglomeration effect. The results show that averaged FUE in China was 0.722, and had a significantly decreasing trend with a significant regional difference and spatial positive correlation in different provinces. The non-agricultural employment ratio was the leading factor for increasing FUE, and its degree of influence showed a decreasing trend from eastern to western China. The different agricultural industry development modes, crop planting patterns adjustment, labor transfer, and policy incentive systems for increasing the non-agricultural employment ratio should be developed for different regions. Farmers’ income had a negative impact on FUE, but the influence degree decreased annually. Education level had a negative impact on FUE and was relatively weak, but the influence degree was increasing. This should strengthen the exploration of a scientific and practical technical training system for farmers on fertilizer use while improving educational levels in different regions on the basis of local characteristics. The impact of disasters on FUE depended on their severity, and a combined weather and disaster forecasting mechanism should be developed.

Replacing synthetic fertilizer by manure requires adjusted technology and incentives: A farm survey across China

Improved recycling of animal manure may contribute to reduce synthetic fertilizer use in cropland, thereby to mitigate environmental and human health threats. However, the potential impacts of such strategies are not well-quantified, and the socioeconomic-cultural barriers are not well-understood, which limit the effectiveness of policy measures, especially in rapidly developing countries. We used a combination of scenario analyses and a farm survey among 1500 farmers across China to explore the impacts of replacing fertilizer by manure and to assess the existence of possible technical, socioeconomic, cultural barriers. We estimated the use of nitrogen fertilizer may be reduced by 3 to 32%, via increased manure recycling from 30% in 2015 to 34 to 70% in 2050, depending on fertilization measures and cropping system. However, only 55% of the interviewed farmers actually used manures. Eight out of 38 factors were evaluated as key barriers to manure use, which involved in the perceived high economic costs of manure use, lack of suitable application technology, and unknown manure quality and availability. Cereal farmers perceived greater barriers than cash crop growers. Several key actions have to be prioritized to achieve the high reduction in fertilizer use. There is need for a transparent manure exchange market, with manure-use advisors, accurate information on the composition and price of manure products, middle man for transporting manure from specialized livestock farms and distant crop farms, and contractors with manure application machinery. This requires specific policy incentives and outreach and control strategies.

Quantifying and optimizing agroecosystem services in China's Taihu Lake Basin

This study examines rice–wheat agroecosystems in the Taihu Lake Basin: one of China's largest commercial grain-farming areas and a region that has faced severe deterioration in water quality. Spatiotemporal changes over the period 1986–2015 in four key ecosystem services (ESs) – grain yield, nitrogen loss, N2O emission, and soil organic carbon (SOC) accumulation – were examined by applying the Agricultural Production Systems Simulator (APSIM) across the basin at county level. Two straw return modes (namely, full straw return versus no return) and three fertilizer-use reduction modes (−5%, −10%, and −20%) were set up to generate six combined scenarios, to propose pathways that reduce the variability of grain production and improve water quality by reducing loss of nitrogen (N loss) – in consideration of the Basin's vital role in agricultural production and the need to protect water quality. Results show that annual grain yield and net five-year difference in SOC accumulation exhibited an overall downward trend from 1986 to 2015, while N2O emission and N loss increased. Two pairs of ESs showed desirable synergies (increasing grain yield and increasing SOC accumulation; decreasing N2O emission and decreasing N loss), encompassing 45.8% and 2.4% of total cultivated land area respectively. Another two pairs exhibited desirable trade-offs (increasing SOC accumulation and decreasing N loss; increasing SOC accumulation and decreasing N2O emission), accounting for 19.0%, and 2.4% of total cultivated land area respectively. There was considerable overlap within counties, which showed high values of grain yield, N2O emission, nitrogen loss, and SOC accumulation in the Basin; but values were relatively high in the east and relatively low in the west. Fertilizer use has significant positive correlations with grain yield and SOC accumulation, and it reduces N loss and N2O emission. Straw return was predicted to raise grain yields and net five-year difference in SOC accumulation and to reduce N loss, but also to increase N2O emissions. Recommended strategies to reduce N loss and stabilize grain supply in the study area are 1) reducing fertilizer use by 20% in areas where N application was above 490 kg N/ha, and 2) implementing straw return and reducing fertilizer use by 5% for areas where N application ranged between 380 and 490 kg N/ha.

The impact of rural-urban migration experience on fertilizer use: Evidence from rice production in China

While a growing number of rural migrants return to engage in agriculture, little attention has been attached to the impact of rural-urban migration experience on fertilizer use. From a theoretical perspective, rural-urban migration experience could affect fertilizer use through remittance, adoption of new agricultural technologies, and improved management philosophy. Using a cross-sectional survey dataset covering 1122 rice-producing farm households in China, this study examines the impact of rural-urban migration experience on fertilizer use in rice production. The treatment effects model and instrumental variable method are employed to account for the self-selection bias and endogeneity of rural-urban migration experience. The survey shows that the heads of 261 farm households had rural-urban migration experience. The econometric results illustrate that rural-urban migration experience is conducive to reducing fertilizer use in rice production. The neglect of self-selection bias and endogeneity of rural-urban migration experience would produce biased and inconsistent results. Moreover, there is a positive impact of rice-fertilizer price ratio on fertilizer use, and the adoption of hybrid rice variety and participation in technology training activities could reduce fertilizer use in rice production.

Effect of Phosphate Fertilizer Type and Nitrogen Application Method on Tuber Yield and Growth Indices of Three Potato (Solanum tuberosum L.) Cultivars

Nitrogen and phosphorus are essential nutrients in growth of plants. In addition, the type and method of fertilizer application play an important role in the efficient absorption of nutrients and reduce fertilizer use. Therefore, an experiment was conducted in a randomized complete block design with three replications in the Bahar city in 2017: phosphorus fertilizer was three levels (no application, triple superphosphate and diammonium phosphate), nitrogen fertilizer with two levels (placement and no-placement) and potato cultivar with three levels (Agria, Banba and Sante). The highest leaf area index (5.27), crop growth rate (13.22 g.m-2) and total dry matter (582.86 g.m-2) were obtained from diammonium phosphate along with nitrogen placement in by using Agria cultivar. The results also showed that under conditions phosphorus deficiency, nitrogen application method did not affect leaf area index, crop growth rate and total dry matter: However, tuber yield of Agria under phosphorus deficiency increased by nitrogen placement treatment. In this study, the use of diammonium phosphate, compared to triple superphosphate, increased leaf area index, crop growth rate, relative growth rate and total dry matter. The effect of nitrogen placement along with triple superphosphate was higher than that of nitrogen with diammonium phosphate. Chlorophyll index was not affected by nitrogen placement when using diammonium phosphate, whereas, nitrogen placement increased chlorophyll index by 6.5% with triple superphosphate. The results also showed that the tuber yield increased by 25.4% when nitrogen used by placement combined with triple superphosphate fertilizer. As a whole, highest tuber yields of all three cultivars, especially in Agria and Banba, were increased under nitrogen placement treatment along with diammonium phosphate.

Influence of seed priming with micro-nutrients followed by rhizobium seed coating on seed vigour, crop growth and seed yield in redgram cv. VBN 3

Biostimulants have been shown to increase nutrient uptake under certain conditions with appropriate dosage, suggesting their usefulness in reducing fertilizer use without affecting yield. However, biostimulants though readily available in the market place do not significantly reduce fertilizer use in conventional agriculture. It is important to find the most promising biostimulants for specific conditions and the amount and methods for the best application, before they can be effective in reducing fertilizer use.