• ISSN 1008-505X
  • CN 11-3996/S

2021 Vol. 27, No. 8

Display Method:
2021, (8): 1-5.
Rotation increases soil phosphorous bioavailability and improves phosphorous nutrition of the latter crop in rotation
HU Yi-fan, LIU Jia-ping, WANG Zi-kai, GUO Lin-yu, ZHAO Pu-sheng, GUO Tao
2021, 27(8): 1305-1310. doi: 10.11674/zwyf.20398
  Objectives  We assessed the bioavailability of soil P to crops in a rotational system using a biological P fractionation method (BBP). The aim was to provide a reference for choosing a suitable crop rotation with the highest nutrient use efficiency and crop output potential.  Methods   A pot experiment was used for the research, no planting crops as control, and the preceding crops planted in the rotation were faba bean (Vicia faba), wheat (Triticum aestivum), ryegrass (Lolium perenne), and hairy vetch (Vicia villosa Roth). For all the treatments, the latter crop planted in the roration was maize (Zea mays). All the treatments were either not fertilized or received 60 mg/kg P2O5 while planting the preceding crops. Soil samples were taken for Olsen-P and biological P fractionation (CaCl2-P, Citrate-P, Enzyme-P and HCl-P) to evaluate available soil P when the crops were harvested. Yield and P content and accumulation in aboveground biomass were measured after harvesting maize.  Results  Crop rotation (P < 0.05) increased maize aboveground biomass. The biomass increase under no P application was higher than that under P application, with the highest increase (185.7%) recorded for the faba bean plant. With P application, there was no significant difference in the aboveground biomass of maize rotated with fababean or ryegrass, but it was significantly higher than that rotated with wheat and hairy vetch. Without P application, rotation (P < 0.05) increased the aboveground P content of maize. Among the preceding crops, ryegrass had the highest P content (66.7%). There was no significant increase in the aboveground P content of maize with the P application compared with the control. However, ryegrass recorded (P < 0.05) higher P content than the other rotation crops. Without P fertilization, planting faba bean, wheat, ryegrass, and hairy vetch increased soil enzyme-P by 20%, 19%, 29% and 15% compared with no planting crops control. In contrast, P application only enhanced soil enzyme-P in faba bean and ryegrass, consistent with their growth-promoting effect. Without P application, planting faba bean, wheat, ryegrass, and hairy vetch decreased citrate-P by 20.99%, 13.30%, 5.05%, and 10.66%, respectively. With P application, the Citrate-P reduction was 32.56%, 22.86%, 20.33% and 27.62%, respectively. Irrespective of applying P or not, planting faba bean and hairy vetch (P < 0.05) decreased soil HCl-P content, but not wheat.  Conclusions  Whether P fertilizer was applied or not , crop rotation reduces soil Olsen-P but promotes subsequent maize growth planted in the rotation. According to the biological P fractionation method, rotation reduced Citrate-P, HCl-P and increased Enzyme-P in soil to some extent, thereby improving the bioavailability of P and the subsequent uptake of P by maize. Ryegrass has the greatest potential to excavate soil P supply capacity among the four preceding crops in the rotation.
Effects of flooding on transformation of inorganic phosphorus fraction in calcareous soils
FAN Hao-long, WANG Xu-gang, CHEN Zhi-huai, GUO Da-yong, SUN Li-rong, JIAO Nian-yuan, SHI Zhao-yong
2021, 27(8): 1311-1320. doi: 10.11674/zwyf.2021036
  Objectives  When applied to soil, phosphorus (P) is easily converted to Fe-P and O-P, which might be affected by the redox process of iron oxide. Here, we studied the valent state and form of iron under flooding condition, and its relationship with the transformation of inorganic P fractions.  Methods  A slurry incubation experiment was employed to simulate flooding condition in the laboratory, using calcareous soil receiving 0 and 78.6 kg/hm2 of P for 6 years (P0, P180). Soil samples were loaded into silling vials, sealed and incubated for 40 days at (30 ± 1)℃ under illumination and dark conditions. Available P and inorganic P fractions were measured before and after incubation. Soil Fe (Ⅱ) content was monitored regularly during the incubation process. The relationship between inorganic P fractions and the iron redox process was discussed.  Results  Soil available P increased dramatically as a result of P fertilization. Soil available P in P0 and P180 treatments were (7.65 ± 1.65) mg/kg and (33.5 ± 2.01) mg/kg. The applied P existed mainly as Ca10-P, Ca8-P, Al-P, and Fe-P fraction, and less than 1% existed as Ca2-P. Flooding incubation in the dark increased soil available P by 8.44 mg/kg and 2.95 mg/kg in P0 and P180 treatments. After flooding incubation, the Ca8-P content decreased while Fe-P, O-P and Al-P increased in P180 treatment. Under illumination and dark condition, Ca8-P decreased by 106.8 and 156.2 mg/kg, Fe-P increased by 23.4 and 47.0 mg/kg, O-P increased by 64.1 and 92.9 mg/kg, and Al-P increased by 33.8 and 34.7 mg/kg, respectively. The observed decrease in Ca8-P under dark conditions was higher than under illumination, while Fe-P and O-P recorded a higher increase in the dark condition than under illumination. We found a significant negative correlation ( P < 0.05) between the amount and maximum velocity of Fe (Ⅱ) reduction and the variation of Ca8-P content, and a significant negative correlation with the increased amount of Fe-P and O-P contents.  Conclusions  Under flooding conditions, Fe (Ⅲ) is reduced to Fe (Ⅱ), leading to the formation of Fe (Ⅱ) and Fe (Ⅲ) mixtures. Consequently, the mixtures have a larger specific surface area and more P adsorption sites, leading to the formation of O-P, Fe-P, and Al-P fractions. Illumination decreases Fe (Ⅲ) reduction, which may be responsible for the lower transformation rate of Ca8-P fraction to O-P, Fe-P, and Al-P fractions.
Regulation of soil microbial biomass nitrogen on nitrogen forms in different growth stages of wheat
LI Jun-jie, ZOU Hong-qin, XU Fa-hui, ZHANG Shui-qing, YUE Ke, XU Ming-gang, DUAN Ying-hua
2021, 27(8): 1321-1329. doi: 10.11674/zwyf.2021044
  Objectives  The availability of soil nitrogen (N) significantly affects plant uptake of the nutrient. Here, we studied the changes of different forms of N in soils under wheat growth to regulate N uptake of crop. The aim was to understand the effect of soil fertility on N supply capacity.  Methods  A wheat pot experiment was conducted with soils having low, medium, and high fertility (denoted as F1, F2, and F3, respectively). The tested soils were collected from the long-term experimental station at “National Long-term Monitoring Station of Fluvo-Aquic Soil Fertility and Fertilizer Efficiency” in Xinxiang, Henan Province. The three soil fertility levels were respectively collected from the treatments of no fertilizer (CK), NPK fertilizer (NPK), and 1.5 times of NPK fertilizer combined with organic fertilizer (1.5MNPK). All treatment pots received the same quantity of fertilizer and transferred to the field with the top 5 cm above the soil surface. Both soil and plant samples were collected at the jointing stage, booting stage, and after wheat harvest. Soil organic N, mineral N (ammonium and nitrate), and immobilized N (microbial biomass N and fixed ammonium) were analyzed. Further, the grain yield, N uptake, and N balance were studied. A structural equation model (SEM) was employed to clarify the contribution of various forms of soil N to crop N uptake.  Results  Mineral N contents decreased during wheat growth. After wheat harvest, the values decreased by 1.8–6.8 mg/kg compared with those before sowing. From jointing stage to harvesting stage, soil microbial biomass N increased first and then decreased in F1, while decreased first and then increased in F2, and continuously increased in F3. Soil fixed ammonium content was significantly increased in F1, F2 and F3 from jointing stage to booting stage, and did not change significantly before jointing stage and after booting stage. The immobilized N pool increased by 10.6 mg/kg in F1 but decreased by 14.3 mg/kg in F2 and 32.2 mg/kg in F3 before the jointing stage, and significantly increased in all the three fertility fields from jointing to booting stage; and decreased by 2.4 mg/kg in F1 and increased by 8.2 mg/kg in F2 and 8.7 mg/kg in F3 from booting to harvesting stage. The highest wheat yield, N uptake, and the lowest N balance were observed in F3. Conversely, the lowest N uptake and highest N balance were observed in F1. Structural equation model analysis showed that immobilized N could directly and positively regulate N uptake by wheat, and organic N could regulate N uptake by influencing immobilized N indirectly.  Conclusions  Immobilized N pool directly and positively regulate wheat N uptake. The organic N pool affects wheat N uptake through the transformation of immobilized and mineral N. As the fixed ammonium content is relatively stable, microbial biomass N plays a crucial role in wheat growth by increasing soil available N. On the other hand, it can hold extra mineral N which is easily lost.
Effects of different organic fertilizer replacement rates on wheat yield and soil nutrients over three consecutive years
LU Wei-dan, LI Jun-hua, LUO Tong, CHEN Li-li, ZHANG Lei, LIU Shuo-kang
2021, 27(8): 1330-1338. doi: 10.11674/zwyf.2021073
  Objectives  The suitable replacement ratio of organic fertilizer in total nutrient input for high and stable wheat yields and maintenance of soil fertility was studied.  Methods  Field trials were conducted at the Agricultural College of Shihezi University in Xinjiang Autonomous Region from 2018 to 2020. Wheat cultivar of Xinchun 38 was used as the test material, and the test soil was gray desert soil. The treatments in the experiment included no fertilization control (CK), conventional chemical fertilizer treatment (CF), and four replacement ratios (i.e., replacement of chemical N and P by 6%, 12%, 18%, 24% organic fertilizer). Organic fertilizers were applied to the soil before wheat sowing, N and P topdressing amount and rate with drip irrigation were applied in similar pattern for all the fertilization treatments, and all straws were returned to the field after wheat harvest. In 2020, plant samples were taken at six growing stages of wheat to analyze the N and P contents, and dry matter accumulation, while wheat yield and yield components were investigated at maturity stage. Soil samples were taken at 0–20 cm depth to analyze available N, P, K and organic matter (OM) contents.  Results  The soil available N, P, K and OM content increased with the increase of the input of organic fertilizers. The available N, P, K and OM contents at filling and maturity stage in replacement ratios of 18% and 24% were significantly higher than those in CK and CF treatments. The dry matter and nutrient accumulation of wheat at the blooming, filling and harvesting stages all increased with the increase of organic fertilizer replacement rate. The wheat dry matter and nutrient accumulation under replacement rates of 18% and 24% were significantly higher than those under CF treatment. N and P fertilizer utilization rate, partial productivity and agronomic utilization efficiency were improved by the inclusion of organic fertilizer in the total nutrients input, with the highest and significant improvements in replacement rates of 18% and 24%. Compared with CF, the substitution treatment of 18% significantly increased the 1000-grain weight and yield.  Conclusions  Replacement of chemical N and P input with organic fertilizers increased soil available N, P, K contents at late growing stage of wheat, improved chemical fertilizer utilization efficiency and yield. The suitable replacement ratio of organic fertilizers dominant its effect, under the experimental conditions, replacing 18% of N and P input by organic fertilizer is recommended for stable wheat yield and maintenance of soil fertility.
Synergistic effects of fertilizer reduction and fulvic acid application on decreasing NaCl content and N, P availability of salinized soil
LIU Xiao-yuan, YANG Jin-song, YAO Rong-jiang
2021, 27(8): 1339-1350. doi: 10.11674/zwyf.2021030
  Objectives  Salinization restricts the sustainable development of agriculture in the Yellow River Delta. The combined effects of fulvic acid and chemical fertilizer reduction on soil desalination and winter wheat yield were studied.  Methods  A pot experiment was conducted in a moderately saline-alkaline soil (pH 7.73, EC 1.18 dS/m). The treatments were composed of conventional N and P fertilizer rate (N100P100), and reduced N or P rate as N85P100, N70P100, P85N100, and P70N100, and the treatments combined with addition of 10 kg/hm2 of fulvic acid (H). At the seedling and harvest stages of winter wheat, soil samples at 0–10 cm and 10–20 cm depths were collected to determine the contents of available P, NO3-N, EC, pH, and ion composition. The wheat yield, N and P contents were determined at harvest.  Results  Chemical fertilizer reduction combined with fulvic acid treatments decreased 0–10 cm soil NO3-N content at seedling and harvest stages, but increased 10–20 cm soil NO3-N content at harvest stage. Soil available P decreased with increasing nitrogen application rate at 0–10 cm soil depth. With increased rate of N application, soil salt, Na+, Ca2+, and Cl contents increased, while Mg2+ content decreased. Compared with N100P100, N85P100, N70P100, P85N100 and P70N100 treatments decreased soil Na+ contents by 29.74%, 55.84%, 28.62% and 43.25%, decreased Cl content by 37.68%, 43.81%, 26.11% and 14.53%. Compared with the same chemical N and P rate treatments, N100P100+H, N85P100+H, N70P100+H, P85N100+H and P70N100+H decreased Na+ contents by 64.63%, 31.20%, 5.14%, 32.66%, and 30.59%, decreased Clcontents by 66.74%, 55.07%, 35.93%, 53.56%, and 70.44%. The yield increase in N70P100+H, P85N100+H were significantly higher than those in N70P100, P85N100. Compared with N100P100, the N uptake efficiency of N85P100 and N70P100 increased by 11.22% and 29.37%, chemical fertilizer reduction with fulvic acid treatments improved uptake efficiency and partial factor productivity of N and P. Through correlation analysis, soil salinity was the direct reason of yield decrease. Na+, Cl and EC were significantly and negatively correlated with uptake efficiency and partial factor productivity of N and P.  Conclusions  The main salt is NaCl in moderately salinized soil of Yellow River Delta. The Na+, Cl contents determine the EC value of soil, and negatively correlated with nutrient efficiency and partial productivity. Reducing N and P application rate could significantly decrease soil salt content, and increase the available P content in 0–10 cm soil. Their combination with application of fulvic acid further decrease the Na+ and Cl contents, alleviate salt stress to crop, increase N and P uptake by winter wheat. Reducing 30% of nitrogen leads to higher soil available P and lower soil EC value than normal and 15% less of nitrogen rate.
Effects of continuous application of chicken manure on field-grown cucumber yield, quality, and soil properties
GUAN Tian-xia, MA Guo-tai, MA Zhi-lu, LIU Zhi-fang, ZHANG Fen-qin, ZHANG You-fu, DENG Jiang-xia, MA Xiao-hua, HAN Yu-si
2021, 27(8): 1351-1360. doi: 10.11674/zwyf.2021024
  Objectives  This research evaluates the effects of different chicken manure application rates on cucumber yield, quality and soil properties in a 4-year experiment to provide a theoretical basis for the sustainable production of cucumber in the study area.  Methods  Field experiments were conducted from 2015 to 2018 in an irrigated desert soil and fluvo-aquic soil in Zhangye, Gansu Province, using ‘Jinyou 35’ cucumber cultivar as test material. Both experiments had five chicken manure application rates: 0 (CK), 15 t/hm2 (CM15), 30 t/hm2 (CM30), 45 t/hm2 (CM45), and 60 t/hm2 (CM60). In 2018, samples of the whole cucumber plant were collected for yield and quality analysis. Further, soi samples (0–20 cm topsoil) were collected to determine soil bulk density, pH, organic matter content, and enzyme activities.  Results  Compared with CK, cucumber yield in CM15 did not increase significantly. However, CM30, CM45, and CM60 (P < 0.05) similarly increased cucumber yield significantly. The values ranged from 26.4%~33.0% in irrigated desert soil and 48.7%~50.1% in fluvo-aquic soil. Compared to the other treatments, CM15 and CM30 recorded higher values for the contents of soluble solids, soluble protein, soluble sugar and Vc in cucumber but the nitrate content in them decreased. An increase in chicken manure application rate decreased soil bulk density and pH but increased organic matter content, especially under CM30–CM60. The soil urease, invertase, alkaline phosphatase, and catalase activities were higher in CM30 and CM45 treatments. Cucumber yield was negatively correlated with soil bulk density and pH and positively correlated with soil organic matter content, urease, invertase and catalase activities. There were (P < 0.05) negative correlations between cucumber soluble solids and bulk density, soluble sugar content and soil pH, nitrate content and organic matter and soluble solids. In contrast, significant positive correlations were found between nitrate content and soil pH, Vc content and soil alkaline phosphatase activity, soluble protein and soil invertase activity, and soluble sugar content and soil invertase activity.  Conclusions  Chicken manure application reduced soil bulk density and pH, increased organic matter content and enzyme activity, which correlates with the yield and quality of cucumber. Considering cucumber yield, quality, soil physical and chemical properties, and fertilizer efficiency, we recommend the application of 30 t/hm2 chicken manure in both soil types tested.
Improving photosynthetic performance and yield of summer soybean by organic fertilizer application and increasing plant density
REN Ting-hu, LI Zong-yao, DU Bin, ZHANG Xing-hui, XU Zheng, GAO Da-peng, ZHENG Bin, ZHAO Wei, LI Geng, NING Tang-yuan
2021, 27(8): 1361-1375. doi: 10.11674/zwyf.2021010
  Objectives  Coordination of N supply and plant density is essential for high soybean yield. Here, we studied the effect of N fertilizer combination and plant density on the photosynthetic performance and yield of summer soybean.  Methods  Field experiments were conducted in the Agronomy Experiment Station of Shandong Agricultural University from 2018—2020. Summer soybean cultivar Qihuang 34 (QH34) was used as experimental materials. We tested four planting densities: 90000 (D1), 120000 (D2), 150000 (D3) and 180000 plants/hm2 (D4). The fertilizer treatments were urea (U), chicken manure (M), and 50% urea and 50% chicken manure (UM), and no nitrogen fertilizer as control (N0). We analyzed N content, gas exchange, the photosynthetic performance of new fully expanded leaves, and soybean yield.  Results  Application of N fertilizer significantly increased soybean yield. M and UM had significantly higher yield than U under all the four density treatments; UM yield was significantly increased than M in 2018 under all the four densities but not significant under high-density treatment (D4) in 2019. There was no significantly difference in the yield of D2, D3 and D4 in 2020. D2 or D3 was more suitable for soybean production in the Huanghuaihai region than D1 and D4. Application of N fertilizer significantly increased the net photosynthetic rate (Pn), light absorption (φPo, PIABS), energy transformation (φEo), electron transfer activities (Ψo), the activities of PSⅡ acceptor side (Vj) and donor side (Wk), and the contribution of N units to PS Ⅱ ability (φPo/SLN, Wk/SLN, Vj/SLN, φEo/SLN, Ψo/SLN). Also, we found that N fertilization increased the positive correlation between Pn and PSⅡ and Pn/SLN and PSⅡ/SLN. The photosynthetic efficiency of soybean was in UM > M > U in 2018, but there was no significant difference between M and UM in 2020. Under the same N fertilizer application, however, the photosynthetic efficiency of D2 and D3 treatments were similar. The Pn was significantly and positively correlated with PSⅡ, Pn/SLN and the contribution of N units to PS Ⅱ ability. Therefore, Pn increase was mainly due to the improvement in PSⅡ performance after nitrogen fertilizer application, which ultimately affected yields.  Conclusions  In the Huanghuaihai region, the optimal plant density of summer soybean is 150000 plants/hm2 (D3). Without a change in the N input rate, urea and chicken manure (UM) combination shows a more satisfactory effect on the photosynthetic efficiency and soybean yield than urea or chicken manure alone, especially in the first and second year. However, chicken manure shows a similar effect since the third year. Therefore, the combination of stable organic fertilizer input and a medium-high planting density is more conducive to high yield, efficiency, and quality soybean production in this area.
Nitrogen and phosphorus surplus of double-rice cropping system under incorporation of Chinese milk vetch and rice straws
2021, 27(8): 1376-1387. doi: 10.11674/zwyf.2021060
  Objectives  Incorporation of rice straw and green manure to the field are important ways to improve paddy soil fertility and reduce chemical fertilizer input. Thus, assessment of the seasonal apparent balance of soil N and P in double-rice cropping system is required for farmland nutrient management.  Methods  An experiment was conducted in acidic red yellow soil and alkaline purple alluvial soil of Hunan Province for 2 years. The treatments included winter fallow and no rice straw return (FRR), Chinese milk vetch incorporation into soil (MvRR), and both Chinese milk vetch and rice straw incorporation into soil (MvRR+St). Chinese milk vetch was planted during winter season and ploughed into soil before transplanting of early rice. Both early and late rice straw were incorporated to the field after rice harvest. The biomass, N and P contents of rice plant (grain, aboveground part and root), and soil physiochemical properties were analyzed.   Results   1) The biomass yield, N and P nutrient contents, N and P absorption of Chinese milk vetch, early rice and late rice in the two paddy soils were similar across all treatments ( P >0.05). MvRR+St significantly increased the available P content by 29.7% and 20.9% in acidic red yellow soil and alkaline purple alluvial soil, respectively, compared with MvRR (P<0.05). 2). Under the current N and P input levels, the soil N and P balance under MvRR+St were surplus in the rotation system and early rice season, but N was deficient and P was basically balanced in late rice season. In early rice season, the N and P surplus in acidic red yellow soil were 88.06 kg/hm2 and 21.26 kg/hm2, respectively; however, the N and P surplus in alkaline purple alluvial soilwere 134.04 kg/hm2 and 27.95 kg/hm2, respectively. In late rice season, the N deficit in acidic red yellow soil and alkaline purple alluvial soil were 29.70 kg/hm2and 30.02 kg/hm2, respectively, and the P surplus were 2.39 kg/hm2 and 6.75 kg/hm2, respectively.  Conclusions  Under current chemical fertilizer rate and incorporation of Chinese milk vetch and rice straws, the annual soil N and P surplus was mainly due to the surplus in early rice season, not in late rice season, in which the soil N was in deficit and P was in basic balance. So, the N and P rate in early rice season should be reduced while the N fertilizer rate in late rice season should be increased.
Alternate wetting and moderate drying irrigation harmonize rice root and shoot growth, improves grain yield and nitrogen use efficiency
XU Guo-wei, ZHAO Xi-hui, JIANG Meng-meng, LU Da-ke, CHEN Ming-can
2021, 27(8): 1388-1396. doi: 10.11674/zwyf.2021034
  Objectives  Alternate wetting and drying (AWD) irrigation, one of the most efficient water use technologies, is widely adopted in rice production worldwide. However, its effects on grain yield and N-use efficiency varies with cultivation method, soil and climate. In this study, we investigate rice root and shoot trait response to AWD to understand the mechanism underlying the beneficial effect of the technology.  Methods  A pot experiment was conducted using a mid-season japonica rice cultivar of Xudao 3 in 2018 and 2019. Three irrigation regimes were set up, namely, conventional irrigation (CI), alternate wetting and moderate drying (−20 kPa, AWMD) and alternate wetting and severe drying (−40 kPa, AWSD). Rice root morphology and physiological indexes were recorded.  Results  AWMD significantly increased root length, root weight, root-shoot ratio, root bleeding sap, and cytokinin content by 13.3%, 6.7%, 10.8%, 8.1%, and 7.4% at heading stage, respectively. AWMD increased the dry matter accumulation from heading to maturity, promoted NSC transport from stem and sheath to grains, and improved grain ATPase activity by 16.3%−18.4%. Also, leaf nitrate reductase (NR) activity increased by 10.9%−44.0% in the main growth stages, N uptake of plants at maturity increased, and the grain filling rate, 1000-grain weight, and grain yield increased as well. Meanwhile, the N absorption and utilization efficiency, agronomic utilization efficiency, and partial productivity increased by 17.2%, 21.6%, and 8.4%. AWSD significantly reduced root length by 30.1%, root weight by 20.8%, inhibited root activity by 40.5%, and the ability to synthesize cytokinins by 34.4% at heading stage. Aboveground growth and leaf photosynthesis rate across the main growth stages were thus decreased, such as reduction of 26.4% at heading stage in photosynthesis rate. Although pre-stored NSC remobilization from stem to grains was enhanced, less post-anthesis dry matter accumulation and grain sink activity resulted in lower rice yield. The plant N uptake (P < 0.05) reduced under AWSD, and NR activity of rice leaf decreased by 19.2%. The N use efficiency (P < 0.05) decreased compared with conventional irrigation. The N use efficiency, agronomic use efficiency, and partial productivity decreased by 18.0%, 34.7%, and 31.8%.  Conclusions  Alternate wetting and moderate drying irrigation effectively improves root morphology, increases root metabolism, promotes aboveground growth, and enhances rice yield and N use efficiency. Alternate wetting and severe dying irrigation is not recommended.
Effects of intercropping rape on soil moisture and quality of apple fruit in an apple orchard in the Loess Plateau
YANG Jian-li, JIA Ru-hao, WANG Chun-li, ZHANG Zhi, WANG Xiao-jun, WANG Zhou-li, ZHAO Xi-ning, FENG Hao
2021, 27(8): 1397-1406. doi: 10.11674/zwyf.2021028
  Objectives  Planting grass in an orchard is one of the models of partially replacing chemical fertilizers with an organic fertilizer in apple production areas. Due to low and uneven inter-season variation in precipitation in the Loess Plateau, planting grass may increase water uptake and deteriorate soil water storage. Therefore, we tested rapes with different water consumption patterns capable of serving as orchard grass.  Methods  The experiment was conducted in 2018 and 2019 in Yan’an City, Shaanxi Province. Three intercropped rape varieties; namely, napus rape Shaanyou 2013 (A-G), spring cabbage type rape Haoyou 21 (A-H), strong winter cabbage type rape Yanyou 2 (A-Y), and clean soil surface control (CK), were used as treatments. Soil moisture, rape growth index and apple fruit quality were measured.  Results  The growth index of rape was (P < 0.05) different among different rape types in two years. The leaf and branch biomass per area were as follows: cabbage type rape (A-G) > strong winter cabbage type rape (A-Y) > spring cabbage type rape (A-H). The soil moisture variation within the apple-growing period was similar in the four treatments, and the most significant variation was observed in the 0–20 cm soil layer. Compared with CK, the soil water content of A-G, A-H, and A-Y in 0–20 cm soil layer decreased by 19.2%, 3.3%, and 8.5%, respectively. In the 20–100 cm soil layer, the soil moisture content increased by –4.9%, 12.1%, and 6.4%. The coefficient of variation of average soil water content in the 20–100 cm soil layer was higher in A-G and smaller in A-H. The three intercropping treatments improved the fruit taste. However, the most significant effect was observed in A-H, where the contents of soluble solids, soluble sugar and VC in the apple of intercropping spring rape was higher than other treatments, improving by 1 and 1.57 percent point, and 47.58%.  Conclusions  Intercropping of cabbage type rape, strong winter cabbage type rape, and spring cabbage type rape are all efficient in increasing soil water storage in 20–100 cm soil depth, thereby decreasing the consumption of soil water during apple dormancy. Consequently, the treatments stimulate the growth and development of apple trees and improve the fruit quality. Spring cabbage type rape performed better than the other two types, and thus, it is recommended for intercropping with dry apple orchards on the Loess Plateau.
Suitable nitrogen fertilization rate effectively improve the quality of summer green tea
LIU Mei-ya, TANG Dan-dan, Jiao Zi-xin, SHI Yuan-zhi, MA Li-feng, ZHANG Qun-feng, RUAN Jian-yun
2021, 27(8): 1407-1419. doi: 10.11674/zwyf.2021012
  Objectives  Excessive application of N fertilizer occurs in 30% of the tea plantation area in China, decreasing tea production efficiency and quality. Therefore, we studied the effect of different N application rates on the sensory quality of green tea.  Methods  The long-term N fertilization experiment of green tea in Hangzhou, Zhejiang Province, started in 2005. The N application treatments included 0, 119, 285, 474, 569, and 712 kg/hm2. Samples of young tea shoots were collected in summer for sensory quality assessment according to the standardized procedure GB/T 23776—2018. Also, the total contents of amino acids, polyphenols, N, and aroma compounds were measured.  Results  N application rate affected aroma but not the appearance, taste, colour, and infusion of leaves (P < 0.05). The total amino acids increased with the increase in N application rate, reaching the peak at N 474 kg/hm2 and decreased at N 569 kg/hm2 and N 712 kg/hm2. The total polyphenol content increased with the increasing of N application rate and reached the highest polyphenols vs. amino acids ratio at N 712 kg/hm2. However, the total N content in the green tea at N 569 kg/hm2 and N 712 kg/hm2 was lower than that at N 474 kg/hm2. Amino acids content was the highest at N 285 kg/hm2 and N 474 kg/hm2, including theanine, glutamine, and aspartic acid, which were all closely related to the umami taste. From N 0–285 kg/hm2, the R-OH compounds such as β-linalool, nerolidol, and ketones increased while alkene contents decreased. There were no obvious regular changes in the aroma related aldehydes, ester compounds, and other compounds.  Conclusions  Nitrogen fertilization at 285–474 kg/hm2 is beneficial for forming good tea quality due to the high contents of umami related amino acids and dominant aroma compounds.
Effects of phosphorus application rate on the growth and quality of Artemisia argyi
CHEN Chang-jie, MA Lin, MIAO Yu-huan, FANG Yan, GUO Lan-ping, LIU Da-hui
2021, 27(8): 1420-1431. doi: 10.11674/zwyf.20609
  Objective  Chinese mugwort (Artemisia argyi) is an important herb resource, and meeting the high demand for it heavily relies on establishing an artificial plantation. In this paper, we studied the effects of phosphorous (P) fertilizer application rate on the growth and quality of mugwort (A. argyi).   Methods  Field experiments were conducted in the main production base of Chinese mugwort (A. argyi) in Qichun, Hubei Province. Newly transplanted seedlings and regenerated seedlings of mugwort were tested in 2018 and 2019, respectively. The P2O5 rate treatments included 0, 60, 120, 180, and 240 kg/hm2 (i.e., P0, P60, P120, P180 and P240, respectively). The agronomic characteristics, leaf yield and the output rate of moxa were measured. Mineral contents, total volatile oil, volatile components, flavonoids and phenolic acids in A. argyi leaves were determined.  Results  The application of P fertilizer significantly increased the leaf yield of A. argyi but not the agronomic characteristics. There was no significant difference in the leaf yield of the four P rate treatments in 2018, and P120, P180 and P240 treatments recorded a similar leaf yield in 2019. According to the fitted curve, the highest leaf yield of A. argyi was recorded at P 166.5 kg/hm2 in 2018 and 157.7 kg/hm2 in 2019. P application increased the uptake of N, P and Ca, but not Mg and Zn, and decreased that of Cu. P application significantly increased the output rate of moxa. The highest moxa yield was obtained at P180 and P120 treatments in 2018 and 2019, which were 21.0% and 12.3% higher than that in P0 treatment. According to the fitted curve, the P rate promoting the highest output was P2O5 140.2 kg/hm2 in 2018 and 165.0 kg/hm2 in 2019. Total volatile oil, eucalyptus oil, and 8 kinds of flavonoids and phenolic acids found in A. argyi leaves were significantly increased by applying P fertilizer. However, the contents of α-thujone and camphor decreased with an increase in P fertilizer application. Principal component analysis was conducted on 14 quality indexes of A. argyi leaves under different P application rates in two years. Three principal components were extracted in the 2018 experiment, whose cumulative contribution rate was 98.9%, and two principal components were extracted in the 2019 experiment, whose cumulative contribution rate was 92.6%. The total score showed that the quality of A. argyi leaves treated with P120 and P180 treatments was higher than taht of other treatments, and the quality of A. argyi leaves treated with P0 treatment was the lowest.  Conclusions  The application rate of P fertilizer affect the growth, leaf yield and quality of mugwort (A. argyi.). Under the experimental condition in Qichun, a reasonable P fertilizer application rate could substantially increase the output of moxa and the ratio of components in the total volatile oil of mugwort. The highest leaf yield was recorded at P2O5 180 kg/hm2 for newly transplanted mugwort and 120 kg/hm2 for regenerated mugwort. A high comprehensive score of mugwort corresponds to high P fertilizer use efficiency.
Optimization of parameters for enzymatic and bacterial hydrolysis of seaweeds and the effects of two products on the stress resistance of Chinese flowering cabbage
YANG Chun-mei, YANG Jin, CUI Dan-dan, LI Li-bin, SHEN Hong
2021, 27(8): 1432-1444. doi: 10.11674/zwyf.2021052
  Objectives  Seaweed is one of the marine resources; its hydrolyzed product has growth-promoting and stress resistance effects. Here we optimized the parameters of two routine seaweed processing and compared their products.  Methods  Single factor and orthogonal experiments were used for the optimization of procession parameters for bacterial and enzymatic hydrolysis of brown algae (Laminaria japonica). In bacteria degradation and enzymatic hydrolysis process, the substrate concentration, algae dosage, pH value and temperature for the degradation were optimized, the used bacteria were Microbulbifer sp. SH-1 and alginate lyase AlgSH7. Meanwhile, the morphology of seaweed cells was observed before and after both kind of hydrolyzation under optical microscope. The effects of the two kinds of products were tested with a pot experiment, using Chinese cauliflower cabbage as test material.  Results  The optimal conditions for alginate lyase AlgSH7 were 2% substrate concentration, 6% enzyme dosage, pH 8.5 and degradation temperature of 44℃. For strain SH-1, the optimal conditions were 2.5% substrate concentration, 1.5% bacterial solution, pH 7.5 and degradation temperature of 32℃. Compared with bacteria degraded product (BDP), the enzyme hydrolyzed products (EHP) increased alginate and total sugar contents and reduced sugar by 141.8%, 57.6%, and 150.5%, respectively. The contents of polyphenol, mannitol, and betaine decreased by 35.3%, 60.6%, 62.6%, respectively. The yield of BDP was 9.3% higher than that of the EHP. Before hydrolyzation, the kelp primitive cells were tightly arranged, and their traits were regular and full. With prolonged bacterial or enzymatic hydrolysis, the visible area of kelp cells became smaller, and the distance between cells increased. After being degraded by enzymatic hydrolysis for 24 h, the visible area of seaweed cells was only 77.2% of that by bacterial hydrolysis. Pot experiments showed that under moderate drought conditions (relative soil water content 50%), the crop biomass treated with EHP was 13.7% higher than that treated with BDP. The crop biomass treated with EHP and water-soluble fertilizer (NPK, N∶P2O5∶K2O=110∶50∶60) was 10.6% higher than that treated with BDP and NPK. Under waterlogging stress conditions (2 cm depth of waterlogging layer), the crop biomass treated with EHP was 7.1% lower than BDP treated biomass but (P<0.05) was higher than that of the control. The biomass treated with EHP+NPK was 5.6% higher than that treated with BDP+NPK. Under salt stress (NaCl content in soil was 24 g/kg), the biomass of Chinese cabbage treated with EHP showed an increasing trend, but the increase was not significant compared with that treated with BDP.  Conclusions  The algae products from enzymatic hydrolysis had higher contents of alginic acid, total sugar, reducing sugar, but lower contents of polyphenol, mannitol and betaine than the algae products from bacterial degradation. Although there was low algae yield from enzymatic hydrolysis, the ensuing product had higher growth-promoting, drought and waterlogging resistance ability, regardless of sole or combined fertilizer application.
Effects of acid-hydrolyzed amino acids addition on the quality and biological effects of different plant residue wastes composting
JIANG Zhong-chun, LUO Fei, LI Xin-yan, ZHANG Nan, ZHANG Rui-fu, XUN Wei-bing, SHEN Qi-rong
2021, 27(8): 1445-1455. doi: 10.11674/zwyf.2021032
  Objectives  We investigated the influence of adding acid-hydrolyzed amino acids (AA) on composting process, N loss prevention, composting quality and product effects of different plant residue wastes.  Methods  Nine different composts were made from herb, cassava and mushroom residues, by adding 5%, 10% and 15% of AA (v/w) to the three kinds of composting piles, respectively. After composting, nine bio-organic fertilizers were made by addition of growth-promoting bacteria (Bacillus amyloliquefaciens SQR9) to conduct pepper and eggplant pot experiments, taking the aforementioned composts as treatments as well. The bio-fertilizer and compost of each kind with the best yield effect were chosen for the following field experiment. The pepper and eggplant field experiments contained 14 treatments, no fertilizer and chemical fertilizer (NPK) controls, three composts, three bio-organic fertilizers, and the combination of compost and bio-organic fertilizers with NPK. The physical and chemical properties of the compost, fresh weight, dry weight, height, stem diameter and SPAD of plant, and the quality and effect of the compost products were evaluated.  Results  AA addition prolonged thermophilic stage of herb and cassava residue composting, while it shortened that of mushroom residue composting. AA addition decreased the pH of composting piles, and generally the more AA was added, the lower the pH. AA addition significantly promoted the decomposition of cellulose, hemicellulose and total carbon of the three raw materials, and the higher the AA addition, the stronger the promoting effects and NPK nutrient accumulation in the composts. Moreover, the electrical conductivity of the piles slightly increased due to the H+ supplementation introduced by AA. In the pot experiment, all the three kinds of composts produced by adding 10% of AA significantly increased the pepper plant biomass and biological indicators, and their combined use with bacteria strain (bio-organic fertilizer) further increased the promoting effects. Combined application of herb residue compost and bio-organic fertilizer had the best growth-promotion effects on pepper, while bio-organic fertilizer plus chemical fertilizer had the best effect on eggplant. With cassava compost, bio-organic fertilizer was the best in both pepper and eggplant. For mushroom residue compost, bio-organic fertilizer plus chemical fertilizer had the best effect on both pepper and eggplant.  Conclusions  Addition of acid-hydrolyzed amino acids (10%) decreased compost pile pH, reduced N loss, prolonged the thermophilic stage, consequently improved the carbon degradation rate and increased the relative content of N, P and K content in composts. The combined use of the composts with beneficial bacteria strains is more efficient in increasing crop biomass and yield.
Comment on special topic
Main process and factors affecting selenium absorption by plant roots and leaves
LEI Hong-liang, CONG Wen-yu, CAI Zhao-lei, Miyasser Abdisamad, ZHAO Jian-yun, WANG Xiao-ge, GAO Guo-ying, WANG Yun-qi, ZHANG Rui
2021, 27(8): 1456-1467. doi: 10.11674/zwyf.20565
Selenium has functions such as anti-cancer, anti-aging and improving human immunity, and after being absorbed and transformed by plants, it can be absorbed and utilized by the organism in a safer and more efficient way. Thus the Se-enrichment in the economic organs is the core of the product functions. However, the Se-enriched products currently available on the market vary in Se contents, and are generally low in Se content. Therefore, it is worth of systematically study on the pathways, key processes and influencing factors of Se uptake by plants, to improve the efficiency of selenium enrichment in plants. Se can be absorbed by roots and leaves of plants. Geographical location, soil parent materials and physicochemical properties affect Se uptake by roots. Se fertilizer characters including source and type and auxins used, foliar spraying concentration of Se, and leaf structure and age, plant growing stages all influence the Se uptake efficiency by plant leaves. Accordingly, recommendations are also proposed for strengthen the study of influencing factors and regulatory mechanisms of selenium uptake by plants and to establish a relatively standard experimental model and evaluation system for selenium-rich products, in order to fill the gap between research and production as soon as possible and promote the healthy development of selenium-rich oriented functional agricultural science.
Short communication
Moderate drought and less fertilizer input promote growth and polysaccharide accumulation in Polygonatum sibiricum Red.
YAN Li, LIU Yu-cui, WANG Xiao-guang, ZHUANG Xin, GUO Jun-jie, LI Jing, HE Li-peng, XIAO Jing-lei
2021, 27(8): 1468-1476. doi: 10.11674/zwyf.2021119
  Objectives  We explored differences in photosynthetic characteristics, growth development, and polysaccharide content of Polygonatum sibiricum Red. under different fertilizers and water stress. The aim was to provide a scientific basis for water and fertilizer requirements in the cultivation and production of P. sibiricum Red.  Methods  Four single-factor irrigation potted experiments were carried out. The irrigation experiment comprised five irrigation treatments (400 mm, 500 mm, 600 mm, 700 mm, and 800 mm) to simulate severe drought, moderate drought, mild drought, sufficient irrigation, and excessive irrigation. The single N, P, and K fertilizer experiments were composed of low, theoretical, experienced, and excess levels under 680 mm irrigation (i.e., average annual precipitation). The detailed quantity of nitrogen fertilizer (urea) applied were 110, 225, 375, and 525 kg/hm2; 260, 525, 750, and 975 kg/hm2 for phosphorus fertilizer(diammonium phosphate), and 75, 150, 225, and 300 kg/hm2 for potassium fertilizer (potassium sulphate). At the mid growth stage of P. sibiricum, the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO2 concentration (Ci) were measured with a photosynthetic meter, and the fluorescence parameter values were determined using a chlorophyll fluorescence detector. Plant height, root length, leaf area, and fresh and dry weight of rhizome were recorded. A UV-Vis spectrophotometer was used to determine polysaccharide content in the rhizome.  Results  The highest photosynthetic capacity and polysaccharide content of P. sibiricum was recorded under moderate drought stress. The growth and development of P. sibiricum was vigorous under sufficient irrigation; however, the photosynthetic rate and polysaccharide content decreased compared with that of moderate drought. Pn, Gs and Tr values were higher under excessive N fertilization than other N treatments. The Pn curve had an N-shape with an increasing N fertilization rate. The highest Fm was observed under low N, experienced P, and low K rate. The leaves of P. sibiricum showed an evident trend of Chlorophyll A Fluorescence Transient (OJIP) under different water and fertilizer rates. The plant height and biomass were higher under low N and low K rates than those in the others. The highest polysaccharide content was recorded under the experienced fertilization rate. There was a significant correlation between plant height and rhizome biomass (P < 0.05) and an extremely significant correlation between leaf area and polysaccharide content (P < 0.01). The elongation of plant height led to high P. sibiricum yield, and leaves with the larger area had higher polysaccharide content.  Conclusions  Moderate drought and slightly low fertilizer application rate than experience, primarily N and K fertilizer, could maintain rhizomes high biomass and large leaf area, improve vigorous photosynthetic efficiency, and high polysaccharide content in the rhizome of P. sibiricum.
Optimal combination ratio of NPK and organic fertilizers for highest saponin and flavonoid contents in Ophiopogon japonicas
DENG Qiu-lin, LI Si-jia, WEN Qiu-shu, LEI Fei-yi, CHEN Yu, ZHOU Juan, LIU Zhe, CHEN Xing-fu
2021, 27(8): 1477-1486. doi: 10.11674/zwyf.20633
  Objectives  Proper fertilization is necessary for high-quality herb cultivation and yield. We studied the optimum combination of N, P, K, and organic fertilizer (OF) in the artificial cultivation of Ophiopogon japonicus.  Methods  Field experiments were conducted using a four-dimensional quadratic orthogonal rotation combination design. All the N, P, K, and organic fertilizers were applied in three times during growth of O. japonicus. Ophiopogonin D (OSD), ophiopogonin D′ (OSD′), methylophiopogonanone A (MONA), methylophiopogonanone B (MONB), and ophiopogonanone D (MOND) were measured after harvest. A model was used to analyze N, P, K, and organic fertilizer’s influence on the main constituents. We used the statistical frequency method to integrate various indicators to obtain the optimal fertilization plan.  Results  The application of N, P, K, and organic fertilizers had significant effects on OSD, OSD′ and MONA content, but not on MONB and MOND. However, fertilizers influenced active constituents to different extent. Potash fertilizers mainly affected OSD′, MONA, and MONB contents, OF mainly affect OSD, and N mainly affect MOND. With the increase of K fertilizer, OSD content gradually increased, while OSD′ decreased first and then increased. The interaction of N × OF was beneficial to the accumulation of OSD; K × OF did not improve OSD′; N × P and K × OF increased MONA; and N × K, P × K, P × OF did not increase MONA. Application of N 307–368 kg/hm2, P2O5 23–27 kg/hm2, K2O 189–190 kg/hm2, OF 2419–2534 kg/hm2 could improve OSD to ≥ 140 μg/g, OSD′ to ≥ 75 μg/g, and MONA to ≥ 100 μg/g.   Conclusions  The practical application of N, P, K, and organic fertilizer can increase saponin and flavonoid contents in O. japonicus, especially MONA and MONB. The optimum N-P2O5-K2O-OF application ratio was 332-25-204-2616 kg/hm2 for OSD, 339-25-199-2352 kg/hm2 for OSD′, and 339-25-173-2400 kg/hm2 for MONA.