Fertilizer Application Treatments Research Articles

Energy, environmental footprints and economic benefit of substituting inorganic fertilizer with organic manure for winter wheat in Huanghuaihai Plain

Manure substitution shows promise for nitrogen (N) management, food security, energy balance and environmental costs reduction. However, there is limited research on this practice in the Huanghuaihai Plain. This study aimed to investigate the energy use efficiency, economic benefits, carbon and nitrogen footprint under two types of N fertilizer (U, urea and M, organic manure), two application rates of N (180 kg N ha−1, U1 for 100 % urea and M1 for 100 % organic manure; 90 kg N ha−1, U2 for 50 % urea and M2 for 50 % organic manure) and no fertilizer application treatment (CK) for winter wheat from 2017 to 2019. Results showed that grain yield and agricultural input cost under N application rate of 90 kg N ha−1 was 15.5 % and 7.8 % lower than that of 180 kg N ha−1, respectively, leading to a significant decrease in economic benefit. Under the same N rate, M1 obtained higher grain yield than U1, grain yield of M2 did no differ in that of U2. Total energy inputs and agricultural input costs of M were 9.5 % and 3.6 % lower than U, resulting in higher energy use efficiency and economic benefit. The reduced agricultural input for M was primarily due to a decrease in the application of inorganic fertilizer. Compared with other treatments, U2+M2 obtained higher grain yield, energy use efficiency, and economic benefit. The carbon and nitrogen footprint on unit grain yield of U1 was increased by 13.7 %-24.1 % and 3.9 %-19.6 %, which was attributed to the increase in direct N2O emissions, indirect carbon emission and losses of reactive N from agricultural inputs. Overall, U2+M2 sustained high productivity and reduced the environmental impact. Substituting inorganic fertilizer with organic manure was a promising strategy to improve agricultural production with less agricultural inputs and environmental footprints in the Huanghuaihai Plain.

Effects of Combined Biochar and Chemical Fertilizer Application on Soil Fertility and Properties: A Two-Year Pot Experiment

A two-year pot experiment was conducted to investigate the effects of the combined application of biochar and chemical fertilizer on soil quality and vegetable growth by adding different proportions of chemical fertilizer and biochar to the soil in 2022 and no fertilizer in 2023. It was concluded that the combined treatment improved the soil’s properties. After two consecutive years of planting vegetables, the improvement of soil properties was the most significant with the 1.5 g biochar + 80% chemical fertilizer optimal fertilizer application (BCF6) treatment. In comparison to the control (CK), soil pH, electrical conductivity, and dissolved organic carbon increased by 0.59 units, 166.6%, and 282.6%, respectively. Soil fertility also improved significantly, indicating that the combined treatments resulted in the slow release of nutrients to enhance the effectiveness of the fertilizers. Co-application significantly increased the yield of the edible parts of Chinese cabbage and improved its quality. The most significant effects of vitamin C content and soluble protein were observed in Chinese cabbage under BCF6 treatment, which were 3.33 and 1.42 times more than the CK, respectively. Utilizing biochar as a partial substitute for chemical fertilizers can improve soil structure and fertility over the long term while reducing the reliance on chemical fertilizers, ultimately providing sustained economic and ecological benefits for agricultural production.

Straw type and nitrogen-water management balance rice yield and methane emissions by regulating rhizosphere microenvironment

Context or problemStraw incorporation improves soil fertility but also poses environmental challenges due to increasing methane (CH4) emissions in paddy fields. Whether nitrogen (N) and water management can balance rice yield and CH4 emissions under different crop straw incorporation is still not well-documented. ObjectiveA three-year field experiment was conducted to probe the comprehensive effects of N application ratios and irrigation regimes on rice yield, rhizosphere soil properties, and CH4 emissions, along with the underlying mechanisms of CH4 emission variations among different straw types. MethodsA two-factor randomized block design was used with two Japonica rice cultivars as materials in 2020 and 2021. The straw incorporation treatment included no straw incorporation (NS), wheat straw incorporation (WS), and rape straw incorporation (RS). The N fertilizer application treatments included local farmers' fertilizer practice (LFP) and increasing basal fertilizer rate (IBF). Two irrigation practices, continuously-flooded irrigation (CF) and alternate wetting and drying irrigation (AWD), were designed under the WS and RS treatments in 2022. Results1) WS-IBF and RS-IBF enhanced yield by 6.70∼9.03 % and 8.13∼9.50 % compared to WS-LFP and RS-LFP, respectively. AWD further increased yield by 6.28∼7.76 % compared to CF. 2) WS-IBF and RS-IBF enhanced dissolved organic carbon (DOC) content, synchronously boosted the methanogens (mcrA) and methanotrophs (pmoA) abundances, but decreased the pmoA/mcrA ratio, which significantly promoted CH4 emission flux in early growth stage. This resulted in a 5.04∼8.01 % and 4.60∼7.88 % increase in CH4 emissions compared to WS-LFP and RS-LFP, respectively, but a decrease in yield-scaled CH4 emissions. AWD reduced DOC content, facilitated the conversion of ammonium N to nitrate N, increased dissolved oxygen content, and hence decreased CH4 emissions by 23.41∼24.38 % compared to CF. 3) RS significantly increased microbial biomass C, N, and related metabolites, leading to a 1.29∼2.73 % increase in yield compared to WS. Meanwhile, RS promoted Nitrospira abundance as well as pterin and flavonoid metabolites associated with mcrA inhibition, while decreasing Anaeromyxobacter abundance, ammonium N, and DOC content, resulting in an increase in the pmoA/mcrA ratio and a noticeable drop in CH4 emissions compared to WS. ConclusionsRS combined with IBF and AWD is a more sustainable integrated practice in light of the synergistic improvement in rice production and environmental benefits. ImplicationsThe results reveal that optimizing N and water management can synergize high-yield and low-carbon by regulating rhizosphere microenvironment in rice production under crop straw incorporation.

Identifying limiting nutrient(s) for better bread wheat and tef productivity in acidic soils of north‐west Amhara, Ethiopia

AbstractFood crop productivity is still low because of the decline of soil fertility in Ethiopia, particularly in north‐western Amhara. Fine‐tuning the source and rate of nutrients is required to solve soil fertility problems along landscape positions. Therefore, this study was initiated to investigate the need to apply selected nutrients to tef and wheat in acidic soils. This nutrient omission study was conducted in 74 farmers’ fields of Gozamen and Machakel districts. The omitted nutrients were sulfur (S), zinc (Zn), and boron (B). Potassium (K) was added, consisting of N, P, K, S, Zn, and B (All+K). Nitrogen plus phosphorus (NP) and no fertilizer treatments were used as positive and negative controls, respectively. Furthermore, 50% and 150% of the All+K treatments were also included. The finding revealed that the application of different nutrient types at variable rates had a significant role in the grain and biomass yield of both test crops in the acidic soils. No tef yield and the lowest yield of bread wheat were obtained from the no fertilizer application treatment. The application of All+K had no significant yield advantage compared to NP fertilizer alone. This implies that N and P are the most yield‐limiting nutrients to produce tef and bread wheat, whereas KSZnB nutrients are not yield limiting. Therefore, refining the rates of N and P in acidic soils is needed for the economical use of fertilizers. Finally, applying blended fertilizers without empirical evidence is not recommended for smallholder farmers in the study area.

Growth and yield of maize in response to reduced fertilizer application and its impacts on population dynamics and community biodiversity of insects and soil microbes

In the North China Plain, farmers are using excessive amounts of fertilizer for the production of high-yield crop yield, which indirectly causes pollution in agricultural production. To investigate an optimal rate of fertilizer application for summer maize, the fertilizer reduction experiments with 600 kg/ha NPK (N: P2O5: K2O = 28: 8: 10) as normal fertilizer application (NFA), (i.e., 100F), were conducted successively during 2020 and 2021 to study the effects of reduced fertilizer rates, including 90% (540 kg/ha; i.e., 90F), 80% (480 kg/ha; i.e., 80F), 62.5% (375 kg/ha; i.e., 62.5F) and 50% (300 kg/ha; i.e., 50F) of NFA, on the plant growth of maize, the dynamics of key population abundances and community diversity of insects, and the composition and diversity of microbial community and finally to find out the N-metabolic enzymes’ activity in soil. Our findings revealed that the fertilizer reduction rates by 10% - 20% compared to the current 100% NFA, and it has not significantly affected the plant growth of maize, not only plant growth indexes but also foliar contents of nutrients, secondary metabolites, and N-metabolic enzymes’ activity. Further, there was no significant alteration of the key population dynamics of the Asian corn borer (Ostrinia furnacalis) and the community diversity of insects on maize plants. It is interesting to note that the level of N-metabolic enzymes’ activity and microbial community diversity in soil were also not affected. While the fertilizer reduction rate by 50% unequivocally reduced field corn yield compared to 100% NFA, significantly decreased the yield by 17.10%. The optimal fertilizer application was calculated as 547 kg/ha (i.e., 91.17% NFA) based on the simulation analysis of maize yields among the five fertilizer application treatments, and the fertilizer application reduced down to 486 kg/ha (i.e., 81.00% NFA) with a significant reduction of maize yield. These results indicated that reduced the fertilizer application by 8.83% - 19.00% is safe and feasible to mitigate pollution and promote sustainable production of maize crops in the region.

Estimation of grain filling rate of winter wheat using leaf chlorophyll and LAI extracted from UAV images

The grain filling rate (GFR) plays a pivotal role in assessing winter wheat grain development and guiding crop variety selection and cultivation strategies. Presently, GFR monitoring primarily relies on destructive sampling methods, which are impractical for swift assessments in extensive agricultural fields. Our study introduces a novel approach for estimating winter wheat grain filling rate (GFR) using leaf chlorophyll content (LCC) and Leaf Area Index (LAI) extracted from UAV imagery. Initially, we established a quantitative relationship between GFR and LAI as well as LCC in winter wheat. Subsequently, UAV multispectral imagery was employed to track the time-series dynamics of LAI and LCC during the grain-filling stage. Ultimately, we constructed an estimation model for winter wheat GFR and achieved plot-scale GFR mapping through UAV-based imaging technology. To identify sensitive vegetation index combinations for LAI and chlorophyll content (SPAD), we employed adaptive re-weighted sampling and continuous projection algorithms, respectively. Following this, we employed partial least squares and random forest algorithms to develop LAI and SPAD estimation models, which were then compared to full-band regression. Finally, GFR estimation was based on the conversion models of LAI and SPAD to GFR. Our findings revealed that, despite variations in water supply, there were no significant differences in GFR trends among the irrigated treatments. However, in the nitrogenous fertilizer application treatments, GFR initially declined with increased nitrogenous fertilizer supply, reaching its peak between 21 and 25 days post-flowering, during which period the differences in GFR among the various nitrogenous fertilizer application treatments were not significant. As the reproductive period advanced, higher nitrogenous fertilizer treatments maintained a higher GFR for a more extended period and experienced a slower decline compared to the lower nitrogenous fertilizer treatments. LAI validation yielded an R2 of 0.84, a root mean square error (RMSE) of 0.39, and a normalized root mean square error (NRMSE) of 10.9%. SPAD validation resulted in R2, RMSE, and NRMSE values of 0.79%, 1.30%, and 12.5%, respectively. The GFR estimation achieved an R2 of 0.77, an RMSE of 0.32 mg/d, and an NRMSE of 11.3%. Mapping the GFR distribution in the field, coupled with water and fertilizer management, supports UAVs in monitoring crop growth and refining field-level water and fertilizer decisions.

Manipulation of flowering and fruiting induction through branch bending and fertilizer application in mandarin citrus cv. Batu 55

Shoot modification for triggering flowering and fruiting induction in tropical mandarin citrus is not extensively documented, hence this research is critically important. The purpose of this study was to determine the influence of branch bending and fertilizer application on flowering and fruiting, hormonal level status, and physiological features in mandarin citrus cv. Batu 55. From May 2021 to March 2022, the investigation was carried out at Farmer‘s citrus orchard Dau in Malang (1,300 m above sea level), East Java, Indonesia. Bending (B1) or unbending (B0) and fertilizer (F1) or no fertilizer (F0) treatments were performed on existing three-year-old Mandarin cv Batu 55 trees with a planting distance of 3 x 3 m. The experiment was set up in a factorial randomized block design with four interaction treatments (B0F0, B0F1, B1F0, B1F1) and three replications. When compared to the control, the bending treatment with fertilizer application treatment raised the percentage of flowering plants by 100%. Five and nine months after treatments, the amount of fruit produced and harvested by this treatment was more than 19 and 1.6 times that of control plants, respectively. Branch bending and unbending treatments had relatively similar effects on the endogenous hormonal status and physiological behavior. Branch bending at the appropriate time of year may be beneficial in stimulating flowering and fruiting in mandarin cv Batu 55.

Application of information fusion technology in maize fertilizer utilization experiments

Abstract The article first utilizes the hyperspectral image grayscale, texture information, and reflectance spectral information at characteristic wavelengths to establish the corresponding quantitative analysis models of nutrient content in maize plants using three modeling methods, MLR, PCR, and PLS. Then from the basis of polarized reflection features, it was inferred that the polarization degree features at sensitive wavelengths were extracted using polarized spectra and combined with chemometric techniques to achieve a quantitative analysis of the degree of nutrient stress in maize. Finally, the feature variables extracted on the hyperspectral and polarized-reflection spectral measurement systems were fused with multiple information. A diagnostic evaluation model of fertilizer utilization with polarization-hyperspectral multidimensional light information was established. The results showed that for the new slow-release fertilizers, SF1 and YNPK had higher nitrogen utilization rates, 9.91% and 7.43% higher than N1PK, respectively. And the nitrogen fertilizer utilization rate was correspondingly higher by 6%-7% in 2020 than in 2019 for each fertilizer application treatment.

Responses of water‐stable aggregates, their associated organic carbon and crop yield to the application of biogas slurry in a fluvo‐aquic soil of the North China plain

AbstractCrop productivity under intensive agriculture depends on the maintenance of fertility and soil structure. Chemical fertilizers are effective in supplying nutrients for crops but eventually lead to loss of the soil organic carbon that is important in supporting soil structure. Biogas slurry is an alternative to chemical fertilizers that potentially can both provide nutrients and promote organic carbon content. A field experiment was conducted to compare the effects of applying biogas slurry (BS), chemical fertilizer (CF) or a combination of both with 50% of nitrogen derived from each (BSCF) and no fertilizer application control (CK) to a fluvo‐aquic soil of the North China Plain. All fertilizer application treatments had equal nutrient supply and were continuously applied over 4 years. Annual yields of wheat and maize were determined. Water‐stable aggregates in size classes >5 mm, 2–5 mm, 0.25–2 mm, 0.053–0.25 mm and <0.053 mm in the topsoil of 20 cm were separated by wet sieving; mean weight diameter (MWD), geometric mean diameter (GMD), percentage of aggregates destruction (PAD) and fractal dimension (D) were derived. The concentrations of organic carbon associated with the aggregates were measured, and the distribution of soil organic carbon (SOC) was quantified. Fertilizer application treatments enhanced total crop yield by 49.1%–75.0%. Fertilizer application also increased the mass proportions of water‐stable macro‐aggregates by 81.6%–164.4%, MWD by 100.0%–264.3%, GMD by 54.5%–227.3%, while decreasing PAD by 15.4%–47.8% and D by 1.0%–3.8% (all relative to CK). The highest proportions of macro‐aggregates, the greatest aggregate stability and the greatest crop yield all resulted from BSCF. All fertilizer application treatments substantially increased the SOC content of water‐stable aggregates, with greater relative contribution in macro‐aggregates. Increased SOC in macro‐aggregates was mainly attributable to mass proportion changes rather than changes in their SOC concentrations. However, SOC concentration tended to account for a larger proportion of the total changes in micro‐aggregates. BSCF also produced the highest total soil organic carbon stocks in aggregates (40.3% and 57.3% greater than CF and CK, respectively). Our work demonstrates that half substitution of chemical fertilizer with biogas slurry is a practical management to enhance soil aggregation and its stability that is associated with a higher crop yield than either treatment individually. It also promotes organic carbon accumulation in soil aggregates, which will support sustainable agricultural development in fluvo‐aquic soil.

A synoptic assessment of groundwater quality in high water-demand regions of coastal Andhra Pradesh, India

Abstract In this article, a coastal region of India having high water demand for irrigation supply was studied for its groundwater quality in temporal and spatial domains. The statistical tests (Shapiro–Wilk W and Anderson–Darling A) of the chemical data of over 100 groundwater samples of the study area indicate the non-parametric nature of the distribution. High concentrations of F− and NO3− ions above drinking water permissible limits were present in 12% and 28% of samples, respectively. Similarly, Cl– ion, and total hardness were higher while Ca2+, Mg2+, and Na+ ions were marginally higher compared to drinking water limits. Kruskal–Wallis (ANOVA) test results indicate that seasonal variations are not very significant among chemical species. Based on irrigation water quality indicators, groundwater samples fall under the excellent to doubtful category during premonsoon and permissible to unsuitable category during postmonsoon season. These inferences were verified by using the Entropy Water Quality Index (EWQI). The spatial contours of the EWQI values clearly suggest that the impact of anthropogenic activities on groundwater is greater in the northern parts of the study area. Optimizing fertilizer application and effluent treatment can improve the groundwater quality thereby achieving sustainable groundwater management in this region.

Effects of the microbial organic fertilizer and plant density on growth, development and yield of roselle (Hibiscus sabdariffa L.) in Central Vietnam

Roselle is a potential crop in Vietnam due to its wide adaptation and many uses. In Thua Thien Hue province – Central Vietnam, the roselle has been grown widely at Phong Dien district. However, local people were growing on their experience and mainly using inorganic fertilizers, which had affected the crop yield partly. In order to towards environmentally friendly and contribute to completing the growing process to expand the safe material area for roselle, the experiments were carried out during 2021 and 2022 to evaluate the effects of microbial organic fertilizer doses and planting density on the growth, development and yield of roselle. The experiment consisted of twelve treatments, with three doses of microbial organic fertilizer (0, 0.5, 1.5 tons/ha) and four planting densities (21000, 24000, 28000, 33000 plants/ha), arranged in a split-plot design with three replications for each treatment. The results showed that in the 0.5 tons/ha of microbial organic fertilizer application treatment and planted at 33000 plants/ha had the highest yield per plant in both crops (568.04 and 590.04 g/plant), with yields of 20.98 and 20.56 tons/ha, respectively. Therefore, it could be recommended to use that amount of microbial organic fertilizer and plant density in the process of growing roselle in Thua Thien Hue and similar ecological regions.

Crop – Livestock integration via maize straw recycling increased carbon sequestration and crop production in China

CONTEXTAgriculture production is crucial in mitigating climate change while securing food productivity. However, the impact of the practices such as organic waste (crop residue and animal manure) recycling or integrating crop-livestock system on productivity and carbon sequestration was unclear. OBJETIVEThis study presents a potential crop-livestock model to enhance carbon sequestration from a whole system perspective. This study aimed to (i) examine the effect of different organic waste recycling on contents of SOC, MBC, and EOC at a depth of 0–60 cm of soil; (ii) analyze the sequestration potential of SOC for different organic wastes recycling models using the substance flow balance method; and (iii) propose suitable organic wastes recycling models for crop and livestock production system in China from the whole-system perspective. METHODSThis study conducted a comparative assessment of carbon sequestration of diverse organic wastes in China using a four-year field experiment and substance flow balance method. The field experiment involved three types of organic waste (raw maize straw (MS), biogas slurry (BS), dairy manure (DM)) and two fertilizer application treatments (unfertilized control (CK), and only chemical fertilizer (CF)). Based on the field results, the carbon flow for different organic waste recycle models was compared using the substance flow approach. RESULTS AND CONCLUSIONSThe content and sequestration of SOC and its fractions increased with the application of organic wastes. The effect of organic wastes on SOC sequestration followed the order DM > MS > BS. Additionally, organic waste, especially DM, significantly increased the sequestration of MBC and EOC by 198% and 359%, respectively, compared to CF. The SOC, MBC, and EOC sequestration rates for DM treatment were 2.9–3.2, 0.3–0.6, and 2.7–3.0 Mg ha−1 yr−1, respectively. On a per-crop yield basis, the “crop straw-livestock-manure-field” model contributed about six times more for SOC sequestration than CF. Future estimation showed that the DM model could reduce chemical fertilizer use by 36% compared to CF, resulting in lower costs. Therefore, the “crop straw-livestock-manure-field” system benefits carbon sequestration and emphasizes the importance of expanding the organic waste management chain. SIGNIFICANCEThe findings have significant implications for the agricultural system, highlighting the importance of integrating the “crop straw-livestock-manure-field” model for carbon sequestration and sustained productivity. The results demonstrate that this model has successfully increased carbon sequestration in the agricultural system. These findings provide an essential option for achieving carbon neutrality in China and promoting sustainable development in agricultural system in other regions.

Penentuan Dosis Pupuk Berdasarkan Data Tonase Tandan Buah Segar (TBS) pada Perkebunan Kelapa Sawit

The productivity of Fresh Fruit Bunch (FFB) in Indonesia is relatively low with an average productivity of below 15 tonnes.ha-1.year-1,which is still very far below its potential, which is around 25 tonnes.ha-1. year-1, one of the contributing factors is the application of fertilizers. neither the type nor the dose has been done precisely. Research on Determining Fertilizer Dosage Based on FFB tonnage data for oil palm plantations has been carried out from March to October 2022 at a private oil palm plantation company located in Nunukan Regency, North Kalimantan Province. The research was carried out on an area of ​​812 ha which was divided into 28 blocks, consisting of 7 treatments each carried out in 4 blocks as repetition. The soil pH conditions are relatively neutral, namely between 6.0-6.9. Fertilizers used are also of various kinds, namely Urea, Rock phosphate, Muriate of potash, Kieserit and Dolomite. The dosage of fertilizer is determined based on the tonnage of fresh fruit bunches produced and compared with the dose of fertilizer according to the recommendations from the leaf sampling unit. This study uses monthly data for each block from March to October 2022 which includes: average stem weight (BJR), number of stems per tree (JJG/PKK), and productivity (tons.ha-1.month-1). The data obtained were then analyzed for variance and continued with Duncan's multiple range test. The results showed that in March, April and October there was a significant difference between the treatments where in March there was a difference in the productivity of fresh fruit bunches where the application of Urea-Rph-MOP-Kieserite fertilizer was 4.3-2.5-1 respectively. .9-2.9 respectively in kg.principle-1.year-1 (P1) shows the highest productivity. In April and October there was a significant difference in the yield per tree where in April the Urea-Rph-MOP fertilizer application treatment was 2.4-1.6-1.8 respectively in kg.principal-1 year-1 (P5) showed that the number of shoots per tree tended to be higher than the other treatments, whereas in October the number of stems per tree tended to be higher in treatment P1. However, there was no significant difference in average length weight from March to October. Thus the dosage of fertilizer can be determined based on fresh fruit bunch tonnage data as an option other than based on the results of leaf sampling units to be implemented in the field.

Effects of Mulching and Application of Organic and Chemical Fertilizer on Greenhouse Gas Emission and Water and Nitrogen Use in Summer Maize Farmland

To explore the effects of mulching and the application of organic and chemical fertilizer on N2O, CO2, and CH4 emission; maize yield; water use efficiency (WUE); and nitrogen fertilizer use efficiency under the conditions of the same nitrogen fertilizer input in summer maize farmland, an experiment was conducted in the Guanzhong Plain of China. In this experiment, the two main experimental factors were mulching (M) and no-mulching, and the secondary experimental factors included no fertilizer application (CK), organic fertilizer substituting chemical fertilizer at 0% (T0, 0.00 kg·hm-2 organic fertilizer and 225.00 kg·hm-2 chemical fertilizer), 25% (T25, 56.25 kg·hm-2 organic fertilizer and 168.75 kg·hm-2 chemical fertilizer), 50% (T50, 112.50 kg·hm-2 organic fertilizer and 112.50 kg·hm-2 chemical fertilizer), 75% (T75, 168.75 kg·hm-2 organic fertilizer and 56.25 kg·hm-2 chemical fertilizer), and 100% (T100, 225.00 kg·hm-2 organic fertilizer and 0.00 kg·hm-2 chemical fertilizer), for a total of 12 treatments. The results showed as follows:1 both mulching and fertilizer application (with or without mulching) factors significantly increased soil N2O and CO2 emissions and reduced soil uptake of CH4(P<0.05). Compared to chemical fertilizer treatments, the organic fertilizer treatments reduced soil N2O emission by 11.8% to 52.6% and 14.1% to 68.0% and increased soil CO2 emission by 5.1% to 24.1% and 15.1% to 48.7% under mulching and no-mulching conditions, respectively (P<0.05). Compared to that under no-mulching, the global warming potential (GWP) under mulching increased by 140.7% to 206.6%. Compared to that in the CK treatment, the GWP of fertilized treatments increased by 36.6% to 67.6% and 31.2% to 89.1% under mulching and no-mulching conditions (P<0.05), respectively. Combined with the yield factor, the greenhouse gas intensity (GHGI) under the mulching condition increased by 103.4% to 166.2% compared to that under the no-mulching condition. Therefore, GHG emissions could be reduced by increasing yields. 2 The mulching treatments increased maize yield by 8.4% to 22.4% and WUE by 4.8% to 24.9% (P<0.05). Fertilizer application significantly increased maize yield and WUE. The organic fertilizer treatments increased yield by 2.6% to 8.5% and WUE 13.5% to 23.2% under the mulching condition compared to that in the MT0 treatment and increased yield by 3.9% to 14.3% and WUE 4.5% to 18.2% under the no-mulching condition compared to that in the T0 treatment. 3 In the 0-40 cm soil layer, the total nitrogen content of mulching treatments was increased by 2.4% to 24.7% compared with that of the no-mulching treatments. Fertilizer application treatments increased the total nitrogen content by 18.1% to 48.9% and 15.4% to 49.7% under the mulching and no-mulching conditions, respectively. Mulching and fertilizer application promoted nitrogen accumulation and nitrogen fertilizer use efficiency in maize plants (P<0.05). Compared to that in chemical fertilizer treatments, the organic fertilizer treatments increased nitrogen fertilizer use efficiency by 2.6% to 8.5% and 3.9% to 14.3% under mulching and no-mulching conditions, respectively. Combining ecological and economic benefits, the MT50 under mulching conditions and T75 under no-mulching conditions can be recommended as planting models to guarantee stable yield and achieve green and sustainable agricultural production.

The interactive effect of grazing and fertilizer application on soil properties and bacterial community structures in a typical grassland in the central Inner Mongolia Plateau

Appropriate grazing pressure and fertilizer application of nitrogen (N) and phosphorus (P) are effective measures to increase grassland productivity. In this study, we report on the interactive effects of grazing intensity and fertilizer application on soil properties, enzyme characteristics, and soil bacterial community compositions. The experiment was set up in a typical grassland in Xilingol, Inner Mongolia, and had 12 treatments (CC, CN, CP, CNP, LC, LN, LP, LNP, HC, HN, HP, and HNP). These consisted of three grazing intensity levels crossed with four fertilizer application treatments: no fertilizer, N fertilizer, P fertilizer addition alone, and both N and P fertilizers addition, subjected to field sampling and laboratory analysis. The results showed that soil alkaline hydrolysis nitrogen was increased by 15 and 13.6% in LN over LC in the 0–10 and 10–20 cm soil depth layers, respectively. Soil available P was 135.6% higher in LP than in LC at 0–10 cm but similar between LP and LC at 10–20 cm. Soil urease activity rose by 46.8 and 39.3% in 0–10 cm soil and was augmented by 63.1 and 60.3% in 10–20 cm soil of LN and LP relative to LC, respectively. Soil catalase (CAT) activity was decreased in response to LNP by 29.4, 23.5, and 26.5% vis-à-vis LC, LN, and LP in the 0–10 cm layer. Soil CAT activity also decreased in 0–20 cm layer for HN and HNP in comparison with HP. The relative abundance of Actinobacteria increased by 38.1 and 45.0% in HC over that in CC and LC, respectively, in 0–10 cm soil; compared with LC, it increased by 35.8 and 21.7% in LN and LNP, respectively. The relative abundance of Proteobacteria was increased in LNP versus LC in 0–10 cm soil. Overall, fertilizer application coupled with a light grazing intensity promoted key soil properties and the relative abundance of a dominant bacterial phylum.

Change in maize yield, N use efficiencies and climatic warming potential after urea combined with Nitrapyrin and NBPT during the growing season in a black soil

Increasing nitrogen (N) utilization and reducing N losses are a globally accepted strategy for N fertilizer application. However, little information has been reported on the fate of N when urea (U) and nitrification and/or urease inhibitors are used in black soils. Therefore, a two-year field experiment was conducted with three N fertilizer application treatments, including urea-only, urea combined with nitrification inhibitor (U+NI), urea combined with NI and urease inhibitor (UI) treatments. Maize (Zea mays L.) yield, N use efficiency, gas emissions, global warming potential (GWP), and apparent N loss were determined. Compared to the other treatments, the U+NI+UI treatment had the significantly (P < 0.05) highest maize yield (11.2 t ha-1), N recovery efficiency (44.5%), agronomic N efficiency (28.7 kg kg-1) and N partial factor productivity (75.8 kg kg-1). Moreover, the U+NI+UI treatment significantly (P < 0.05) reduced the peak of Ammonia (NH3) volatilization and nitrous oxide (N2O) emissions, cumulative NH3 volatilization and N2O emissions, and apparent N loss compared to the U treatment. Although there was no significant difference in cumulative N2O emissions between the U+NI+UI and U+NI treatments, the U+NI+UI treatment significantly (P < 0.05) reduced cumulative NH3 volatilization by 55.3%, GWP by 16.2%, and apparent N loss by 28.2% compared to the U+NI treatment. Overall, the combination of urea with urease and inhibitors is a good practice to improve maize yield and N use efficiency while reducing environmental impacts in black soil.

Key soil properties influencing infiltration capacity after long-term straw incorporation in a wheat (Triticum aestivum L.)–maize (Zea mays L.) rotation system

Straw incorporation is increasingly being adopted in wheat (Triticum aestivum L.)–maize (Zea mays L.) rotation systems to improve soil physiochemical properties. To identify the main soil properties influencing infiltration capacity under long-term straw incorporation in a wheat–maize rotation system, the study set four treatments: no straw incorporation and fertilizer application, wheat straw incorporation with 276 kg nitrogen/ha, wheat and maize straw incorporation with 276 kg N/ha, and wheat and maize straw incorporation. The initial, average, and final infiltration rates were calculated to represent soil infiltration capacity. Compared with other treatments, wheat straw incorporation with 276 kg nitrogen/ha treatment significantly decreased soil bulk density, soil aggregate (DMWD) mean weight diameter measured using the dry sieving method, and weight rate of soil aggregates with diameters greater than 0.25 mm measured using the wet sieving method, and significantly increased total soil porosity, soil capillary porosity, field capacity, and weight rate of soil aggregates with diameters less than 0.25 mm measured using the wet sieving method. In contrast, wheat and maize straw incorporation treatment significantly increased soil bulk density and noncapillary porosity, but decreased total soil porosity, capillary porosity, and field capacity. The results of partial least squares regression indicated that the soil moisture content and DMWD were the primary factors influencing initial infiltration rate with positive regression coefficient. Higher total soil porosity, capillary porosity, field capacity, and DMWD contributed to higher final infiltration rate, while higher soil bulk density and noncapillary porosity were correlated with a lower final infiltration rate. The key influencing factors of average infiltration rate were soil bulk density, soil moisture content, total soil porosity, capillary porosity, and DMWD. The wheat straw incorporation with 276 kg nitrogen/ha treatment had higher infiltration rates than no straw incorporation and fertilizer application treatment. However, with an increase in straw amount, the influence of straw on infiltration showed a law of diminishing marginal returns. Therefore, wheat and maize straw incorporation with 276 kg nitrogen/ha treatments had a lower infiltration rate than wheat straw incorporation with 276 kg nitrogen/ha treatment. In addition, wheat and maize straw incorporation treatment had the lowest average and final infiltration rates of all treatments, indicating that excessive straw incorporation without nitrogen fertilizer had adverse effects on infiltration rates. This study furthers understanding of the influence of long-term straw incorporation on soil hydrological processes and helps rationally use straw resources in wheat–maize rotation systems.

Determining organic-inorganic fertilizer application threshold to maximize the yield and quality of drip-irrigated grapes in an extremely arid area of Xinjiang, China

Imbalanced water and fertilizer systems have limited the yield and quality of grapes in extremely arid areas. The combined application of organic (OF) and inorganic fertilizers (CF) has been proven to be one of the practical approaches to improving yield and quality. Nevertheless, very few studies have focused on the irrigation amount in organically fertilized and drip-irrigated grapes. Hence, in this study, four combined application ratios of organic and inorganic fertilizers (70%OF + 30%CF, 50%OF + 50%CF, 30%OF + 70%CF, and 0%OF + 100%CF), and four irrigation amounts (630, 675, 720, and 765 mm) were set coupling in a two-year field experiment. Generally, under four irrigation levels, combined organic-inorganic fertilizers increased soil nutrients and improved seedless white grape growth, yield, and quality. The results of the combined fertilizer application treatments showed that the content of available nitrogen (55.97–102.60%), available phosphorus (49.41–124.74%), and available potassium (60.70–124.33%) in soil increased significantly compared with those values under a single application of inorganic fertilizer. In addition, the combined application increased the length of new shoots and leaf midribs (grapes) by 3.16–11.88% and 7.35–15.15%, respectively; this application mode also significantly enhanced transpiration rate (Tr), stomatal conductance (Gs), and net photosynthetic rate (Pn). Furthermore, the grape yield increased by 6.68–19.12%, and the fruit quality notably improved (except for the index of fruit shape). Under the four irrigation amounts, two-year average yields were reported as 17.53, 20.60, 23.31, and 22.71 kg/ha, respectively. Additionally, we used four evaluation methods to assess the fruit quality and compared their correlations with the comprehensive evaluation model. And we concluded that the principal component analysis method (PCA) is best suited for evaluating drip-irrigated grapes’ quality. Then, we applied the PCA to seek proper irrigation management; the results displayed that a suitable irrigation amount of 720 mm and the ratio of organic-inorganic application of 50% organic fertilizer + 50% inorganic fertilizer is recommended. However, further research is required to investigate the effects of soluble and complete organic fertilizers application on drip-irrigated grapes.

Effects of Basal Selenium Fertilizer Application on Agronomic Traits, Yield, Quality, and Se Content of Dryland Maize.

To explore the efficiency of selenium (Se) fertilizer application in dryland maize, we tested five Se fertilizer application treatments: 0 g ha-1 (Se0), 75 g ha-1 (Se1), 150 g ha-1 (Se2), 225 g ha-1 (Se3), and 300 g ha-1 (Se4). Compared with Se0, Se2 increased the leaf area, chlorophyll content, internode length, plant height, and ear height by 7.95%, 3.20%, 13.19%, 1.89%, and 7.98%, respectively. Se2 and Se3 significantly affected the stem internode diameter, cortex thickness, and cellulose content, which were positively correlated with lodging resistance. Compared with Se0, Se3 promoted the contents of soluble sugar, crude protein, crude fat, and starch in grains, which increased by 9.48%, 6.59%, 1.56%, and 4.82%, respectively. It implies that maize grain application of Se significantly improves their Se content. Se1 did not observably influence the growth of maize, and the promoting effect of Se4 on maize decreased. The lodging resistance of maize as analyzed by Pearson correlation analysis correlated with the application of Se fertilizer. It proved that higher yield, grain quality, grain Se content, and lodging resistance of stems were concerned with Se fertilizer application in the range of 150-225 g ha-1. The results provide useful information for Se fertilizer treatment in dryland maize.

Interaction of Soil Nutrients and Arsenic (As) in Paddy Soil in a Long-Term Fertility Experiment

In this study, we examined the interaction between arsenic (As) and nutrients in paddy soil which received pig manure and chemical fertilizers for 36 years (since 1984). The treatments consisted of: CK (without fertilization); NPK (chemical nitrogen, phosphorus and potassium fertilization); NPK30%M (70% NPK plus 30% manure); NPK50%M (50% NPK plus 50% manure); and NPK70%M (30% NPK plus 70% manure). The combined application of pig manure and chemical fertilizer improved grain yield, soil pH and nutrient levels compared to chemical fertilizer application treatment. In comparison to CK, grain yield increased by 55.9%, 75.0%, 74.9% and 71.9%, respectively under the NPK, NPK30%M, NPK50%M and NPK70%M treatments. Soil As concentration increased by increasing the amount of manure input, and the highest concentration of As was 0.64 mg kg−1 found in the NPK70%M treatment. Increasing the rate of manure application decreased the As bioaccumulation coefficient (BAC) for rice grain. SOC, total N and P showed a positive correlation with the soil-available As concentration and negative correlation with BAC. Furthermore, the partial least square model (PLS) showed that the soil pH and SOC were the most influencing factors on BAC among the different properties of soil, which explained the 75.4% and 17.6% of total variations, respectively. This study concluded that the addition of pig manure together with chemical fertilizers can increase crop production by supplying essential nutrients, but the concentration of As in manure should be monitored to reduce soil and food contamination.