2021 Vol. 27, No. 9
Detection rate and concentration of tetracycline antibiotics in organic fertilizers raw materials and commercial products in China
2021, 27(9): 1487-1495. doi: 10.11674/zwyf.2021061
Objectives Livestock manures from intensive farming often contain a certain amount of antibiotics, which could get into farmland when applied as fertilizers. To provide a basis for their safe recycling, we investigated the concentration of tetracycline antibiotics (TCs) in the raw materials and commercial products of organic fertilizers in China. Methods 180 samples of organic fertilizer raw materials (including auxiliary materials) and 244 samples of commercial organic fertilizer products were collected nationwide for the analysis of oxytetracycline (OTC), tetracycline (TTC), chlortetracycline (CTC), and doxycycline (DXC). The commercial organic fertilizer products only included those made from livestock manure. Results The total detection rate of the four TCs in all the samples was 24.29%, and 35.00% in raw materials and 16.39% in the commercial products, with the rate being lower in the latter than in raw materials. Detection rate of one or two types of antibiotics in total samples was 80.58%, 92.50% in the commercial products and 73.02% in raw materials. The detected concentration of the 4 TCs was in the order of CTC (22.11 mg/kg) > OTC (2.49 mg/kg) > TTC (1.74 mg/kg) > DXC (0.71 mg/kg), and the detection rate was in the order of OTC (14.39%) > DXC (11.08%) > CTC (8.96%) > TTC (6.13%). The detection rate of the four TCs in raw materials was pig manure (83.33%) > chicken dung (66.67%) > cow dung (30.77%) > sheep dung (24.42%). Residues, including oil residues (dry cakes), yeast residues and bone meal were also detected, indicating that TCs were not only widely used in animal husbandry but also had been extended to mushroom cultivation and leftovers from the animal-derived food industry. The contents of CTC, TTC and OTC in sheep dung were higher, and those of CTC and OTC in pig manure were higher. The removal rates of TCs in commercial products were in the order OTC (77.81%) > CTC (75.02%) > TTC (72.84%) > DXC (62.80%). Inner Mongolia and Gansu were the regions with the highest detection rate and concentration of the 4 TCs investigated. Conclusions The composting process of organic fertilizer generally removes 62.80%−77.81% of the four kinds of TCs in organic fertilizer raw materials, and the order of removal rate is OTC>CTC>TTC>DXC. At present, the detection rate of the four TCs in all the raw-materials and commercial organic fertilizer products is 24.29%, and that in commercial organic fertilizer products (16.39%) is lower than in raw materials (35.00%).
Effects of new fertilizers on the yield and soil biological activity of three major food crops: A global meta-analysis
2021, 27(9): 1496-1505. doi: 10.11674/zwyf.2021062
Objectives In recent years, with the transformation of agricultural development mode from resource consumption to green ecology, the development of new fertilizers has become a hot topic. Recent available studies mostly focused on the effects of new fertilizers on the crop yield, nitrogen (N) uptake and nitrogen use efficiency (NUE), but our understanding about their effect on soil biological activity was relatively limited. This study aims to analyze the effects of new fertilizer on the yield of three major food crops (wheat, maize and rice) and soil biological activity, and also to provide a scientific basis for the wide production and application of new fertilizers. Methods In this study, we obtained the data from “CNKI” and “Web of Science” databases. A total of 29 relevant papers conducted in field trials were obtained with “wheat”, “maize”, “rice”, “yield”, “microbial biomass”, “enzyme activity” and “new fertilizer” as the keywords, producing a total of 545 data groups coming from 32 independent trials. Using conventional fertilizers as the control and new fertilizers as the experimental group, Meta-analysis was used to integrate the effects of new fertilizers application on crop yield, enzyme activity and soil microbial biomass. Results The yield, aboveground N uptake and NUE of three crops were significantly increased by new fertilizers application, with an increment rate of 8.4%, 9.9% and 36.8%, respectively, compared with those of conventional fertilizers application. Similarly, the application of new fertilizers significantly increased soil microbial biomass nitrogen (14.6%), but had no significant effect on soil microbial biomass carbon. Soil phosphate metabolism-related enzymes activities (8.6%) and oxide-related enzymes activities (5.7%) were significantly increased by applying new fertilizers, but no significant difference was found for soil carbon and nitrogen cycling enzyme activities between these two treatments. Conclusions The application of new fertilizers increased the yield, aboveground N uptake and NUE of three major crops, and also increased soil microbial biomass N, soil phosphate metabolism-related enzymes activity and oxide-related enzymes activity, and further improved the soil biological activity of agricultural ecosystem.
Mechanism of silicon application to improve constitutive and inducible resistance to aphid during physiological metabolism of maize
2021, 27(9): 1506-1522. doi: 10.11674/zwyf.2021086
Objectives Rhopalosiphum padi is one of the main pests in maize production, its growth and reproduction severely affect the yield and quality of maize. Silicon (Si) application is capable of inducing aphids resistance by maize. In this study, we explored the beneficial effects of Si on the antioxidant system, secondary metabolism and signal transduction pathway of maize. Methods A maize hydroponic experiment was carried out, and the tested aphid was Rhopalosiphum padi. The four treatments were no Si application without aphid infestation (–Si–A), no Si application with aphid infestation (–Si+A), Si application without aphid infestation (+Si–A), and Si application with aphid infestation (+Si+A). At 48, 60, 72, 96 and 120 h after aphid infestation on maize plant, the density of aphids was surveyed. The CAT, SOD, H2O2, and MDA contents in the antioxidant system, the PAL, PPO, LOX, and lignin contents in the secondary metabolism and signal transduction substances (JA and SA) were analyzed. The content or enzyme activity of the tested indices in maize without aphid infestation was defined as the constitutive resistance. The difference between the indices before and after aphid infestation was defined as inducible resistance, and Si's effect on these resistances was discussed. Results Aphids density increased with infection time. The density of aphids at 60−120 h after aphid infestation without Si application was 12.50%−40.18% higher, and that with Si application was 12.36%−49.44% higher than that at 48 h after aphid infestation. At the same infestation time, the aphid density with Si application was 15.29%–20.64% lower than without Si application. During the whole incubation period, Si application improved the activity of the constitutive CAT and SOD, reduced the constitutive H2O2 and MDA by 4.41%−15.35% and 5.35%−17.95% (P < 0.05), increased the activity of inducible CAT across the infestation time except at 72 h after aphid infestation, reduced (P < 0.05) inducible SOD activity, and inducible H2O2 increased first and subsequently declined. The activities of constitutive PAL, LOX, PPO, and constitutive lignin (P < 0.05) increased, while inducible PPO activity and lignin content decreased. The activity of inducible PAL increased first and then decreased, inducible LOX activity fluctuated, the content of constitutive JA and SA (P < 0.05) increased, the content of inducible SA increased by 43.77%−117.48%, and the content of inducible JA decreased. Similarly, irrespective of Si application, the activity of constitutive CAT, SOD, PAL, LOX, and PPO, the content of H2O2, MDA, lignin, JA and SA were (P < 0.05) higher than those of the inducible type. The PCA and correlation analysis results showed that constitutive and inducible CAT activity, SOD activity, inducible H2O2 content, and SA content were better indicators reflecting maize’s constitutive and inducible resistance to aphids. Conclusions Silicon application improved the aphid resistance of maize by affecting the constitutive and inducible resistance of each substance in the antioxidant system, secondary metabolism and signal transduction pathways of maize, which provided a theoretical and scientific basis for the ecological regulation of aphids in maize fields.
Mechanism of improving water and nitrogen use efficiency and reducing soil nitrate leaching by suitable irrigation during the anthesis stage of wheat
2021, 27(9): 1523-1533. doi: 10.11674/zwyf.2021042
Objectives This study investigated the effects of soil water content during the flowering period of wheat on N accumulation and transfer and soil NO3−-N leaching to provide a theoretical basis for water conservation to promote high wheat yield and efficient N use. Methods Field experiments were conducted during 2018–2019 and 2019–2020 wheat-growing seasons using Jimai 22 as the test cultivar. Three water treatments were set up during the anthesis stage: no watering (W0), watering 0–40 cm soil depth to a relative moisture content of 70% (W1) and 85% (W2). The wheat N accumulation and translocation at anthesis and maturing stage were determined; wheat yield and N fertilizer efficiency were investigated at the maturing stage, and soil nitrate-nitrogen content in 0–200 cm soil depth was analyzed. Results After anthesis, the average N transfer in the vegetative organ of W1 at maturity was 11.6% and 7.3% higher than W0 and W2, and the N transfer rate in W1 was 9.5% and 6.1% higher than W0 and W2. At the maturity stage, the grain N distribution in W1 was 22.5% and 12.9% higher than W0 and W2, but the N distribution in the leaf and spike axis and glume in W1 was (P < 0.05) lower than in W0 and W2, thus increasing N harvest index. Compared with W0 and W2, W1 treatment reduced NO3−-N content in 60–120 cm soil depth, increased wheat N uptake by 11.4% and 6.5%. The apparent excess soil N in W1 treatment was 51.0% and 40.9% lower than W0 and W2, reducing the risk of NO3−-N leaching into the deeper soil layer. W1 reduced the residual inorganic N in 0–200 cm soil layer and the apparent excess soil N, which benefited absorption and utilization by wheat roots. Compared with W0 and W2, a thousand-grain weight of W1 treatment was 11.0% and 5.4% higher, grain yield was 25.9% and 11.8% higher, and the water use efficiency was 17.0% and 12.7% higher in the two growing seasons. Similarly, N use efficiency was 13.0% and 4.9% higher in W1 than W0 and W2, and the N uptake efficiency was 11.4% and 6.5% higher on average. Conclusions Irrigating 0–40 cm soil layer to a moisture content of 70% during the flowering period benefits N transfer from vegetative organs to grains in the middle and late grain filling stages and at maturity, thereby promoting grain N accumulation, yield, N harvest index, and water use efficiency. Irrigating to 70% of the soil water capacity at the flowering stage reduces the NO3−-N content in 60–120 cm soil depth, thereby decreasing the risk of NO3−-N leaching, which improves wheat N use efficiency and uptake for production. Excessive irrigation leads to excessive downward movement of NO3−-N, which affects root absorption. Insufficient water, on the other hand, decreases the transport of N to the grains.
Response of nitrogen and dry matter accumulation in middle and high yield wheat cultivars to water and nitrogen supply
2021, 27(9): 1534-1547. doi: 10.11674/zwyf.2021043
Objectives For a good wheat production with a high yield, water and nitrogen (N) fertilizer are two critical elements. Here, we studied the response of middle and high yield wheat cultivars to water and N supply rates, with yield as the target. Methods Field experiments with a randomized complete block design, two factors and three levels were carried out from 2016 to 2018, with Taikemai 33 (middle yield cultivar) and Jimai 22 (high yield cultivar). The three irrigation rates were 300, 450, and 600 m3/hm2, and the three N application rates were 135, 180, and 225 kg/hm2. The dry matter (DM) and N accumulation before and after the flowering stage were analyzed, and the quantity of N accumulated in grain was calculated. The relationship among yield, yield components and the N and DM accumulation were examined. Results Water, N application rate and their interaction (P < 0.05) influenced panicle number, grain number per panicle, 1000-grain weight, grain yield, and partial N productivity of the two wheat cultivars. The response of the middle yield wheat to water was W2 > W3 > W1 and N2 > N3 > N1 for N application rate. The response of the high yield wheat cultivar to water was W3 > W2 > W1 and N2 > N3 > N1 for N application rate. Wheat yield was positively correlated with the transfer of post-anthesis DM accumulation in grain but negatively correlated with it before anthesis. Our result indicated that DM accumulation and its transfer to the grain before anthesis was important for yield formation. The wheat yield had a positive linear correlation with the transfer of N accumulated before anthesis and was negatively correlated with that after anthesis. Thus, N accumulation before anthesis was more critical than after anthesis for grain N accumulation. There were positive correlations among pre-anthesis N accumulation, total N accumulation, pre-anthesis N transfer, post-anthesis N transfer, the contribution of pre-anthesis N transfer to grain, and N harvest index (P < 0.05). There was a positive correlation among spike number, grain number per spike, and grain yield (P < 0.05). Conclusions The transfer of DM accumulated after anthesis and N accumulated before anthe‘sis has a significant effect on yield formation and N accumulation in grain, respectively. Suitable water and N supply influences the contribution of DM and N transfer before and after anthesis. The high and middle yield wheat cultivars have a similar response to N 180 kg/hm2. However, the high yield cultivar prefers higher irrigation water rate (600 m3/hm2), while the middle yield type prefers lower irrigation water rate (450 m3/hm2).
Critical phosphorus dilution curve and phosphorus nutrition diagnosis of summer maize in Guanzhong Plain
2021, 27(9): 1548-1559. doi: 10.11674/zwyf.2021065
Objectives This study analyzes the relationship between aboveground biomass and maize phosphorus (P) content under different P application rates to construct a critical P dilution curve for fast diagnosis of maize P nutrition. Methods Field experiments were conducted in Guanzhong Plain, Shaanxi Province in 2019 and 2020, using the maize cultivars Zhengdan 958 (ZD958) and Yuyu 22 (YY22) as test materials. The four treatments of P2O5 application rates were 0, 60, 120, and 180 kg/hm2. The aboveground parts of maize plants were sampled at jointing, tasseling, filling, and maturity stages to determine dry matter accumulation, P concentration, and yield. The data obtained in 2019 were used to construct the critical P dilution curve model and the corresponding P nutrition index (PNI). The data obtained in 2020 were used to verify the models' accuracy. Results Increased P application rate (P<0.05) increased yield, aboveground biomass, and P concentration of summer maize, but there was no significant difference (P>0.05) between the two varieties. With increasing P application rate, the yield of summer maize increased at first and later decreased, with P120 treatment recording the highest. The yield effect equation showed that the average theoretical maximum yield of the two varieties of summer maize in the years under study corresponds to a P application rate of 110.2 kg/hm2. P application had no significant effect (P>0.05) on the number of ears per hectare but increased the kernel number per ear and 100-grain weight. However, the effect of the application on kernel number per ear was greater than that on 100-grain weight. The aboveground biomass was in the order P0<P60<P180<P120, with no significant difference (P>0.05) between P180 and P120 treatments. Maize P concentration increased with increasing P application rate; however, it decreased with the advancement of growth and the accumulation of aboveground dry matter by weight. Based on the aboveground dry matter weight and P concentration of maize plants in 2019, the critical P dilution curve model for summer maize was established as: Pc=8.11DM−0.22 (R2=0.886). The RMSE and n-RMSE between the calculated and the measured plant P concentrations in 2020 were 1.146 and 18.23%, showing high accuracy. The PNI values calculated with the critical P concentration curves increased and decreased across the growth stages, and this was augmented by increased P application at each growth stage. PNI was also positively correlated with relative P uptake (RPupt), relative aboveground biomass (RDW), and relative yield (RY). Conclusions The constructed critical P dilution curve model and P nutrition index model (PNI) could help predict P nutrition conditions of summer maize at different growth periods. Therefore, it is useful for instant P nutrition diagnosis and optimal P fertilization in summer maize.
Yield and economic benefit of corn/needle leaf pea intercropping system under different nitrogen fertilizer reduction rates
2021, 27(9): 1560-1570. doi: 10.11674/zwyf.2021075
Objectives The potential of nitrogen (N) fertilizer reduction in the corn/needle leaf pea intercropping system was studied in the Hexi oasis irrigation area to provide a theoretical basis for the efficient use of N resources. Methods The long-term field experiment of corn/needle leaf pea intercropping was located in the Wuwei oasis irrigation area since 2011. The experimental treatments were no fertilizer application (i.e., control) and conventional N fertilizer application (N100) under the mono-maize system, and corn/needle leaf pea intercropping system with the conventional N fertilizer was applied at 95%, 90%, 85%, 80% and 0% of the conventional rate. The maize and needle leaf pea yield, maize yield components, and the economic benefits of the intercropping system were investigated from 2014 to 2019. The partial productivity of N (PPN), agronomic efficiency of N (AEN), and the N fertilizer contribution rate (FCRN) were calculated. Results The corn/needle leaf pea intercropping had obvious yield advantages, and the merit increased with the elongation of experimental years. Compared with N100, the intercropped corn grain yield under 85% N application rate did not change significantly (P > 0.05), although the plant height and stem diameter of corn was inhibited. Spike height to plant height rate decreased; spike number per area, grain number per spike and 100-grain weight had no obvious change. The harvested needle leaf pea hay and grain were 1419 kg/hm2 and 1637 kg/hm2, corresponding to an increased economic benefit of 3813 yuan/hm2. The PPN and AEN (P < 0.05), and the FCRN (P < 0.05) decreased in 2019, but the decrease in other years were not significant. When the N application rate was 80% of the conventional rate, the intercropped corn grain yield (P < 0.05) decreased by 8.77%. However, the harvest of 1438 kg/hm2 needle leaf pea hay and 1569 kg/hm2 needle leaf pea grain in the intercropping system increased the economic benefit of the system by 2098 yuan/hm2. The PPN significantly increased by 14.04%, and the AEN had no obvious change. However, spike number per area, grain number per spike, 100-grain weight, plant height, stem diameter, spike height, spike length, spike diameter, and the FCRN of corn significantly decreased. Conclusions Under long-term corn/needle leaf pea intercropping, the highest N reducing potential is 15%, with no decrease in corn yield and the additional harvest of needle leaf pea hay and grain increases the economic benefits. The highest N reducing potential in corn is 20% under intercropping of corn and neddle leaf pea, in which the decreased corn yield and FCRN could be compensated by the harvest of needle leaf pea hay and grain, and the economic benefits of the intercropping system and PPN are significantly increased in the Hexi oasis irrigation area.
Effects of smooth vetch (Vicia villosa Roth var. glabrescens) incorporation on nitrogen fertilizer replacement and soil fertility improvement in a maize-green manure rotation system
2021, 27(9): 1571-1580. doi: 10.11674/zwyf.2021068
Objectives The study was conducted to evaluate the effects of smooth vetch (Vicia villosa Roth var. glabrescens) turnover amount on maize growth and soil properties in a maize-green manure rotation system. The aim was to provide theoretical support for the chemical fertilizer reduction potential of smooth vetch. Methods The field trials were conducted in Songming County, Yunnan Province in 2018 and 2019, with the maize (Heinuo No.1) as test material. The experiment included five treatments: winter fallow (CK), incorporation of smooth vetch at 15000 kg/hm2 (G1), 30000 kg/hm2 (G2), 45000 kg/hm2 (G3), and winter fallow with chemical fertilizer application N 270 kg/hm2 (FN). The smooth vetch was planted during winter season and returned to field before maize cultivation. NPK content and accumulation in the aboveground part of maize, yield and yield components were examined at harvest, including soil total and available N, P, and K and organic matter content. The soil pH was measured as well. Results The maize yields of treatments G1, G2, and G3 were equivalent to 78.14%, 88.88%, and 92.86% of treatment FN in 2018, and 98.92%, 104.22%, and 113.91% of treatment FN in 2019. However, the plant height, ear height, bald ear length, and single ear weight were not significantly different (P>0.05) among all the treatments. The grain N content of the FN treatment was (P<0.05) higher than other treatments, and the N content of its straw was significantly higher than that of CK and G1 treatments. In 2019, the N accumulation in the shoots of G3 treatment was (P<0.05) higher than those of FN and G1 treatments, which were 42.03% and 33.91%, respectively. In 2018, corn P accumulation in the FN treatment was significantly higher than those of CK and G1 treatments, with no difference in K accumulation among the treatments. Except for CK, there was no significant difference (P>0.05) in P accumulation among the four treatments in 2019. The three green manure treatments accumulated more K than the FN treatment. There was no difference in soil nutrients among the treatments in 2018. In 2019. soil available N, available K, total N, and organic matter content increased significantly, enhancing soil fertility as the green manure application increased. The aggregated boosted tree (ABT) analysis indicated that soil total N and single ear weight contributed the most to maize yield, both accounting for 20.89%. Conclusions The incorporation of smooth vetch at a high rate in the first year (45000 kg/hm2) and moderate rate (30000 kg/hm2) in the second year relegates the need for N fertilizer in maize production. Smooth vetch incorporation at the above rates could provide similar or even higher N nutrition for maize to produce higher yields. After two years of incorporating smooth vetch, the soil total and available N and K and organic matter contents increased.
Combining N-inhibitor and chicken manure with reduced N fertilizer to improve the conversion and utilization of fertilizer N in a paddy soil
2021, 27(9): 1581-1591. doi: 10.11674/zwyf.2021005
Objectives The nitrogen supply and utilization of soil and fertilizer-derived N were studied under the condition of reduced urea N input and combined with N-inhibitors and chicken manure, to provide a theoretical basis for rice cultivation in Northeast of China, in terms of improving the nitrogen use and fertilizer efficiencies. Methods 15N isotope tracer technology was adopted in a rice pot experiment. The five treatments included: no nitrogen fertilizer control (CK), conventional rate of urea (urea-15N), 80% urea N + 20% chicken manure N (NM), 80% urea N+ inhibitor (NI), 80% urea N + inhibitor + 20% chicken manure N (NIM). The contents of ammonia nitrogen and microbial biomass N in soil and urea-derived nitrogen, and nitrogen content of rice plant at different growth stages were analyzed, investigated the rice yield was investigated. Results 1) NI treatments had considerable soil ammonium N and fertilizer derived N supply ability compared with N treatment, inhibitors had a compensatory effect on nitrogen reduction. NM treatment had markedly higher N supply ability at the tillering and filling stages, compared to N treatment. Compared with N treatment, soil NH4+-N in NIM treatment increased by 19.2%, 66.3%, and 36.5%; NO3−-N content increased by 13.9%, 12.7%, and 17.3% at returning green, tillering and filling stage, respectively, 15NH4+-N content increased by 14.59 mg/kg at tillering stage. 2) N and NI treatments had no significant effect on soil microbial biomass carbon (MBC) content, however, NM and NIM treatments significantly improved soil microbial biomass N (MBN) content at the returning green and filling stage (P < 0.05). Compared with N treatment, the MBC content in NIM treatment increased by 32.61%, 29.23%, 53.46% and 2.85%, and the MBN content increased by 147.98%, 22.97%, 133.33% and 24.63% at the returning green, tillering, filling and mature stages, respectively, while 15N-MBN increased by 22.56 mg/kg at the tillering stage. 3) N-inhibitor with chicken manure addition increased the rice yield and biomass. Compared with N treatment, NIM increased the biomass, yield and nitrogen uptake of rice by 83.59%, 124.18% and 46.66%. It also significantly increased fertilizer N residue in the soil by 56.48% and reduced the fertilizer N loss by 78.7%. Compared with N treatment, NIM treatment had a significant effect on N absorption and utilization of fertilizer, and its N absorption, N utilization rate and N agronomic efficiency were significantly higher than other treatments. Conclusions For brown paddy soil of northern China, the addition of inhibitor (1% PPD+1% NBPT+2% DMPP) and chicken manure could replenish soil N supply. Based on 20% reduction in urea, augments with the application of inhibitors and chicken manure increased the fertilizer utilization rate and increased the rice yield. From the perspectives of fertilizer N release and utilization in rice, NI and NIM treatments shows superior agronomic performances.
Biocrusts increase soil nutrient levels by increasing the nutrient retention ability of surface soil on the Loess Plateau
2021, 27(9): 1592-1602. doi: 10.11674/zwyf.2021055
Objectives Biocrusts affect the nutrient content in the topsoil, playing a crucial role in the nutrient accumulation and cycling. Here, we studied these effects through a leaching experiment. Methods In the Loess Plateau of China, aeolian and loess soils with and without biocrusts on the surface were sampled at every 2 cm layer in a 0−10 cm soil depth profile. The soil organic matter content, total C, N, and P were measured to determine biocrust effects. Soil leaching experiments were conducted in the four soil samples using Cl−, K+, and Ca2+ as tracers. On completion of the leaching experiments, the ion content in each soil layer was measured to explore the effects of biocrust on surface soil’s nutrient retention and adsorption abilities of surface soil. Results 1) The nutrient contents in biocrusts layer were 0.43−10.51 times as compared with the uncrusted soil. And the nutrient contents at a soil depth of 0−10 cm under biocrusts were higher than those without biocrusts, the organic matter, total C, N, and P in soils with biocrusts increased by 1.4%−184.9% compared with the same layer of the uncrusted soil. 2) The nutrient contents in the biocrusts layer were 38.2%−557.1% higher than that in the underlying soil, while the nutrient contents in the surface layer of uncrusted soil were only 13.4%−213.9% higher than that in the underlying soil. These results indicated nutrient accumulation in the surface soil caused by biocrusts. 3) The nutrients in the soils with biocrusts recorded lower leaching than those in uncrusted soil under the same conditions. Cl− was completely leached out of the soils with and without biocrusts in our experiments, while the K+ and Ca2+ were only partly leached out, with 21.9%−47.4% lower in the biocrusts covered soil than the uncrusted soil. Moreover, Cl−, K+, and Ca2+ contents in the biocrust layer were (P<0.05) higher by 8.8%−340.4% than those in the uncrusted soil, and by 14.5%−62.7% in the soil under the biocrusts layer after the leaching experiments. 4) Biocrusts significantly increased the adsorption or retention ability of surface soil for Cl−, K+, and Ca2+ by 27.8%−118.1% compared to the uncrusted soil; the adsorption ability of the biocrusts layer for the tested ions was in the order Ca2+>K+>Cl−. Conclusions Our findings show that biocrusts can enrich soil nutrients in the surface soil while also increasing the surface soil's nutrient retention ability, which is favourable for nutrient accumulation in degraded soil.
Effects of phosphorus fertilizer application rates on physicochemical properties and yield of potato starch
2021, 27(9): 1603-1613. doi: 10.11674/zwyf.2021110
Objectives This study investigated the effects of P application rates on the physicochemical properties and yield of potato starch used for different purposes. Methods Field experiment was conducted in Heilongjiang Province in 2019 and 2020, using ‘Youjin’ and ‘Kexin 13’ potato cultivars as test materials. The treatments were low (P2O5 45 kg/hm2, LP), medium (P2O5 90 kg/hm2, MP), and high (P2O5 135 kg/hm2, HP) P application rate, with no P application designated as the control (CK). The physicochemical properties and yield of potato starch were determined. Results P application reduced the amylose content of potato starch by 3.19%−5.14% for ‘Youjin’ and 2.97%−9.05% for ‘Kexin 13’ compared to CK; the decrease in cultivar ‘Youjin’ in 2019 under HP was more pronounced than other treatments. The addition of P to potato starch increased its transparency and swelling capacity while decreasing its solubility. Compared with CK, HP (P<0.05) increased starch transparency by 15.00% (Youjin) and 25.74% (Kexin 13), increased swelling power by 3.94% (Youjin) and 7.90% (Kexin 13), and decreased solubility by 12.23% (Youjin) and 21.84% (Kexin 13). The median diameter (D50) of ‘Youjin’ was the highest under MP treatment (11.58% higher than CK), while ‘Kexin 13’ recorded a decrease in D50 with an increasing P application rate. The D50 of ‘Kexin 13’ in HP was 5.02% lower than CK. However, the D50 of ‘Kexin 13’ was larger than ‘Youjin’. The starch yield of ‘Youjin’ under MP treatment and ‘Kexin 13’ under HP treatment was the highest, corresponding to 31.36% and 29.66% increase compared to CK. Conclusions Appropriate P fertilizer application rate efficiently increased the dry matter accumulation and starch yield of potato. Further, it can boost amylopectin levels and improve potato starch’s transparency and swelling power. The optimum application rate of P2O5 is 90 kg/hm2 for ‘Youjin’ and 135 kg/hm2 for ‘Kexin 13’.
Effects of combining zinc and phosphate fertilizers using different methods on the availability of zinc and phosphorus in soil
2021, 27(9): 1614-1626. doi: 10.11674/zwyf.2021107
Objectives We explored Zn and P availability in the soil amended with phosphate fertilizers resulting from Zn's physical and chemical combination. The aim was to choose a suitable Zn and phosphate combination method for high-efficiency utilization of the nutrients. Methods Zn sulfate heptahydrate of 0.5 and 5 parts by weight were combined with 99.5 and 95 parts by weight of K2HPO4 through the physical mixture (P+Zn) and chemical reaction (PZn) methods, respectively. Further, four Zn-containing phosphate fertilizers were prepared, P+Zn0.5, P+Zn5, PZn0.5, and PZn5. The composite structure of Zn and P were observed using X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR). The change in the soil available Zn and P content was studied using a soil culture experiment. The alkaline phosphatase activity and pH of the fluvo-aquic soil were measured simultaneously. Results 1) The combination of Zn and P increased the available Zn content in the soil by 2.90%, 12.17%, 24.64% and 10.86% for P+Zn0.5, P+Zn5, PZn0.5, and PZn5, respectively. PZn0.5 and PZn5 increased soil available Zn content by 21.13% and 7.37% than P+Zn0.5 and P+Zn5. In addition, PZn0.5 reduced Zn fixation rate by 10.49 percentage points than PZn5. 2) Compared with K2HPO4 control, the combination of Zn and P (P < 0.05) increased soil available P content. At 60 days of cultivation, the soil available P content of PZn0.5 and PZn5 were (P < 0.05) higher than P+Zn0.5 and P+Zn5 by 5.76% and 5.70%, respectively. P+Zn0.5, PZn0.5, and PZn5 reduced soil P fixation rates by 1.45, 1.19, and 0.25 percentage points than K2HPO4 control. 3) Compared with K2HPO4 control, P+Zn0.5 and P+Zn5 increased the soil alkaline phosphatase activity at the beginning of cultivation and the effect of PZn0.5 was better than PZn5. 4) PZn0.5 and PZn5 reduced soil pH at the beginning of cultivation. The reduction was more prominent in PZn0.5 than PZn5. Conclusions The combination of Zn and phosphate fertilizer by the physical mixing and chemical reaction processes could reduce Zn fixation in the soil, and the products obtained from the chemical reaction method performed better. The chemical reaction between Zn and phosphate fertilizer can also reduce P fixation in the soil, similar to soil pH reduction. Adding 0.5% zinc sulfate heptahydrate to phosphate fertilizer through a chemical reaction is recommended.
Effects of organic acid composition in the decomposed liquid of green manure crops on the activation level of AlPO4 and FePO4·2H2O
2021, 27(9): 1627-1635. doi: 10.11674/zwyf.2021092
Objectives The organic acid composition of decomposed green manures was studied to understand the different effects of green manures on improving soil phosphorus availability. The study aims to provide a reference for selecting suitable green manure crops for an efficient rotational system. Methods Six types of green manure crops were selected for the experiment: milkvetch (Astragalus sinicus L.), radish (Raphanus sativus var. Longipinnatus), Orychophragmus violaceus, double-low rapeseed (Brassica napus L.), double-high rapeseed (Brassica napus L.), and mustard (Brassica juncea). The green manure plants were cut and loaded into centrifugal tubes, and 1 mL of soil extract solution was added and isolated before incubation for 45 days under natural shading conditions. The decomposed liquids of the green manure crops were collected by centrifuge to determine the contents of 10 organic acids (propane diacid, malic acid, citric acid, oxalic acid, lactic acid, tartaric acid, acetic acid, succinic acid, maleic acid and fumaric acid). A simulation experiment was conducted by eluting AlPO4 (Al-P) and FePO4·2H2O (Fe-P) from the decomposed liquids, the water-soluble P contents in the dilution were then analyzed. Results The total organic acid content in the decomposed solution of Orychophragmus violaceus was the highest, followed by radish, double-low rapeseed, mustard, double-high rapeseed, and milkvetch. The descending order of the 10 organic acids by concentration was tartaric acid, propane diacid, citric acid, succinic acid, lactic acid, malic acid, acetic acid, oxalic acid, maleic acid and fumaric acid in all decomposed liquids of the green manure crops. tartaric acid and propane diacid accounted for more than 15% of the total organic acid, while maleic acid and fumaric acid accounted for less than 1%. The decomposed liquid of radish had the highest capacity to activate insoluble P, corresponding to a theriotical activation of 0.6–1.2 kg insoluble P per 1000 kg of radish plant. This was followed by milkvetch (0.6–1.0 kg per 1000 kg) and mustard green manure (0.6–1.0 kg per 1000 kg), and Orychophragmus violaceus recorded the lowest activation capacity of 0.2–0.6 kg per 1000 kg. Correlation analysis showed that the activation level of Al-P was positively related to the content of citric, malic, and oxalic acids. The activation level of Fe-P was positively related to tartaric acid content. Conclusions The proportion of citric, malic, and oxalic acids in the total organic acids of the green manure crops is closely related to the activation level of Al-P, and that of tartaric acid is related to the activation level of Fe-P. The decomposed liquid of radish has the highest tartaric acid and a relatively higher proportion of citric and succinic acid than other green manures. This implies that radish has the highest ability to activate Fe-P. Milkvetch and mustard rape have higher proportions of oxalic, citric and succinic acids in the total organic acids, indicating that they have a strong ability to activate Al-P. Therefore, radish, milkvetch, and mustard are recommended as green manures in rotational systems to increase the biological availability of Al-P and Fe-P in soils.
2021, 27(9): 1636-1647. doi: 10.11674/zwyf.20604
Objectives Phosphorus (P) is an essential nutrient element for crop growth and development. In plants, P is mostly stored in mature grains in the form of phytic acid. Non ruminants, including humans, cannot digest phytic acid to utilize P and other nutrient elements owing to their chelation with phytic acid. This leads to decreased nutrition value and increased loss risk of P resources to environments via grain harvest and animal manure. Reducing grain phytic acid content is thus an important focus in crop breeding. We summarized the research progresses on pathway of P entering crop grains, the physiological processes regulating grain phytate-P, and genetic improvement strategies reducing grain phytate. Main advances The accumulation of phytate-P in grain was mainly composed of three steps: transporting inorganic P (Pi) from xylem or phloem and subsequently to grains, synthesizing phytic acid from Pi, and loading phytic acid into vacuole for storage. To date, many membrane transporters and metabolic enzymes involved in these processes have been characterized, such as SULTR3;4, SULTR3;3, PHT1;4 transporters mediating inorganic P transport to grains; MIPS, ITPK, IPK1 enzymes respond to phytic acid synthesis; and MRP proteins for vacuolar storage of phytic acid. We further compared yield performances and other agronomic traits of grain phytate mutants, and evaluated the different strategies of genetic improvements. The shortcoming of low grain phytate mutants remained, such as defective in yields formation and seeds germination rate. Prospects In the future, three approaches can be emphasized for breeding low-grain-phytate crop varieties, including modulating spatial-temporal expression of key genes, exploring superior gene allelic variation, and cultivars-specialized P nutrition management.
2021, 27(9): 1648-1655. doi: 10.11674/zwyf.2021219
Objectives We assessed available soil nutrients using a nutrient abundance index and graded the spatial distribution of the former based on GIS and soil nutrient grading in Xiliao River Plain. Further, we proposed fertilizer recommendations across the spatial layout. Methods Xiliao River Plain in Inner Mongolia covers Horqin District, Kailu County, Naiman Banner, Horqin Left Back Banner, and Horqin Left Middle Banner. Based on 15421 soil test data and 143 “3414” maize trail data, we calculate the spatial interpolation results of alkaline N, available P, and readily available K in the cultivated soil using GIS. Combining GIS with the method of soil abundance index, the nutrient management zones of soil alkaline N (AN), available P (AP), and readily available K (AK) were divided in Xiliao River Plain. The fertilizer uptake of different soil NPK nutrient combinations was determined. The map of N, P, and K zonal fertilization of maize was developed. Results The spatial distribution of soil nutrients in the cultivated soil was uneven. The content of soil AN was low, and the contents of soil AP and AK were medium in Xiliao River Plain. The most important combinations of soil AN–AP–AK were low (N)–medium (P)–medium (K), medium (N)–medium (P)–medium (K), and medium (N)–medium (P)–high (K). The area ratio of each combination was 42.4%, 14.1%, and 13.5%. There were better logarithmic relationships between the soil AN, AP, and AK content (x) and the economic optimal fertilizer rate (y). Nitrogen optimal fertilization model was y = –102.5ln (x) + 617.22, phosphorus optimal fertilization model was y = –36.11ln (x) + 174.1, and potassium optimal fertilization model was y = –25.89ln (x) + 180.96. Under the different soil nutrient combinations, the optimal dosage combinations of N, P2O5, and K2O for maize were 202–110–58 (kg/hm2), 168–107–57 (kg/hm2), and 164–102–47 (kg/hm2). Conclusions The relative yield of maize has a good logarithmic relationship with soil AN, AP, and AK content. The simulation effects of the function between the relative yield of maize and soil nutrients differ under different methods.When dividing the abundance index of soil alkaline nitrogen, available phosphorus, and readily available potassium in the Xiliao River Plain, grading intervals of the relative yield of 75% and 85% are suitable. Under the big data support of soil nutrients, the regional fertilization management system can be established accurately and rapidly by combining the GIS and abundance index methods.
Optimum application of seaweed extracts promote the yield, quality and nutrient absorption of peach fruit
2021, 27(9): 1656-1664. doi: 10.11674/zwyf.2021058
Objectives The effects of adding different ratios of seaweed extracts (60% seaweed extract, 6.5% alginic acid, 5% humic acid, pH 6.7, and 1.15 g/mL density) to NPK fertilizer were studied for the efficient use of seaweed extract. Methods Peach cultivar of ‘Zhongtao 8’ was used as the test material in a two-year field experiment. The tested application dosages of seaweed extracts were designed as the ratio of NPK fertilizer used in four topdressings (w/w): 0% (CK), 5% (T1), 10% (T2), 20% (T3), and 40% (T4). The seaweed extracts were applied to the soil with NKP fertilizer simultaneously. We measured the single fruit weight, yield, fruit quality, color, and nutrient content of peach. Results With increasing of seaweed extract dosage, peach yield and quality increased first and then decreased. The highest yield and soluble solid content were recorded in T2 in 2019 and 2020, with 31.77%, 40.67% for yield and 10.67%, 7.20% for soluble solid content higher than CK. Further, the yield of T2 was (P < 0.05) different from other treatments. However, the titratable acid content of T2 was the lowest, which was 11.11% and 50.00% lower than CK in 2019 and 2020. In 2019, except for the soluble sugar in T1, the soluble sugar content and sugar to acid ratio in all the other seaweed extract treatments were lower than CK. Except for T4 in 2020, the soluble sugar content and sugar to acid ratio in other seaweed extract treatments were higher than CK, and T2 was 20.55% and 166.29% higher than CK. Seaweed extract application promoted nutrient absorption and fruit coloring in 2019 and 2020. The highest fruit K content was 16.7% (T2) and 11.94% (T3) higher than CK in 2019 and 2020. Based on the principal component analysis, the total score of T2 was the highest in the two consecutive years. Conclusions Seaweed extract shows a satisfactory effect in increasing peach fruit yield and quality while improving fruit coloration. The appropriate application dosage of seaweed extracts is 10% of topdressed NPK fertilizer.
2021, 27(9): 1665-1674. doi: 10.11674/zwyf.2021071
Objectives Nitrogen (N) fertilization affects the growth, yield and quality of Artemisia argyi. We investigated the optimal N application rate for high yield and quality to provide a scientific basis for standardized N fertilization of A. argyi in Qichun. Methods Two field experiments were conducted at the experimental base of A. argyi in Qichun, Hubei Province, from 2018 to 2019. The first field was newly planted, and the second was continuously planted with A. argyi. We used P2O5 120 kg/hm2 and K2O 120 kg/hm2 as the basis to set up five N (urea) application rates of 0, 60, 120, 180 and 240 kg/hm2. The agronomic traits, yield, leaf quality and N use efficiency of A. argyi were studied. Results The growth of A. argyi was sensitive to N application rate. The emergence number and leaf yield of A. argyi reached the peak at N 168 kg/hm2 and N 172 kg/hm2 in 2018 and 2019, respectively. The corresponding maximum leaf yield was 7 030 kg/hm2 and 6 200 kg/hm2. Higher N application rate increased N and Cu contents in A. argyi leaves, while the K and Mg contents were the highest at N60 and N120, respectively. The P content was the highest at N240. The highest moxa yield of A. argyi (1 743 kg/hm2 in 2018 and 1 426 kg/hm2 in 2019) was obtained at N 147 kg/hm2 and N 142 kg/hm2, respectively. The total volatile oil and its components, β-eugenone and caryophyllin, increased continuously. The contents of eucalyptol, α-platycladone, camphor, borneol and α-caryophyllene reached the highest at N 180 kg/hm2. The highest phenolic acids and flavonoids contents were obtained at N 60−120 kg/hm2. In addition, N partial productivity, N absorption rate, and N agronomic efficiency of A. argyi leaves showed a decreasing trend with the increasing N application rate. Conclusions The yield and quality response of A. argyi to N fertilizer application rate were the same in new and old fields. The N application rate for the highest yield was N 170 (168−172) kg/hm2, N 144 (141−147) kg/hm2 for the highest moxa yield, N 180 kg/hm2 for the highest volatile oil contents, and N 60−120 kg/hm2 for the highest phenolic acids and flavonoids contents.