scholarly journals Effects of water saving and nitrogen reduction on the yield, quality, water and nitrogen use efficiency of Isatis indigotica in Hexi Oasis

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiucheng He ◽  
Huizhen Qiu ◽  
Kuizhong Xie ◽  
Yucai Wang ◽  
Juan Hu ◽  
...  
Keyword(s):  
Nitrogen Fertilizer ◽  
Irrigation Water ◽  
Application Rate ◽  
Gansu Province ◽  
Utilization Efficiency ◽  
Nitrogen Application ◽  
Isatis Indigotica ◽  
Irrigation Amount ◽  
Use Efficiency ◽  
Nitrogen Application Rate

AbstractIsatis indigotica planting is the backbone of the medicinal industry in Hexi Oasis, Gansu. In order to solve the problems insufficient water resources and excessive application of nitrogen fertilizer in this area, this paper explored the irrigation and nitrogen levels that can meet the multiple goals of Isatis indigotica. The two-factor split-plot field experiment (2018‒2019) was conducted in Minle County, Gansu Province, China, which contains 9 treatments. There were three levels of irrigation water: W1(low), W2(medium), and W3(high). The soil moisture contents were 60–70%, 70–80%, and 80–90% of the field water-holding capacity, respectively. The nitrogen application rate was classified into three levels, N1(low), N2(medium) and N3(high), which were 150, 200 and 250 kg N/ha, respectively. The standard local irrigation water amount and nitrogen application rate corresponded to W3N3. The results showed that the yield of Isatis indigotica increased first and then decreased with the increase of irrigation amount and nitrogen application rate, the yield of W2N2 is 12.2–17.1% higher than that of W1N1, the yield of W3N3 was 12.1–17.5% lower than that of W2N2. Saving water and reducing nitrogen can improve the quality of Isatis indigotica, compared with W3N3, the indigo, indirubin, (R,S)-epigoitrin and polysaccharides of W2N2 increased by 4.5–5.9%, 2.7–3.1%, 5.2–6.0%, and 1.8–2.1%, respectively. With the increase of nitrogen application rate, the water use efficiency (WUE) first increased and then decreased, as the irrigation volume increases, WUE decreases. Compared with W3N3, the WUE of W2N2 increased by 24.3–27.2%. With the increase of water input, the nitrogen fertilizer use efficiency (NUE) first increased and then decreased, as the nitrogen application rate increases, NUE decreases. Compared with W3N3, the NUE of W2W2 increased by 31.8–34.5%. Therefore, W2N2 can improve quality and increase water and nitrogen utilization efficiency on the basis of ensuring yield.

scholarly journals Nitrogen and Rainfall Effects on Crop Growth—Experimental Results and Scenario Analyses

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2219
Author(s):  
Saadi Sattar Shahadha ◽  
Ole Wendroth ◽  
Dianyuan Ding
Keyword(s):  
Soil Water ◽  
Application Rate ◽  
Crop Growth ◽  
Water Dynamics ◽  
Nitrogen Application ◽  
Soil Water Dynamics ◽  
Application Rates ◽  
Use Efficiency ◽  
The Impact ◽  
Nitrogen Application Rate

Nitrogen (N) fertilization is critical for crop growth; however, its effect on crop growth and evapotranspiration (ETc) behaviors under different amounts of rainfall is not well understood. As such, there is a need for studying the impact of nitrogen application rates and rainfall amounts on crop growth and ETc components. Agricultural system models help to fill this knowledge gap, e.g., the Root Zone Water Quality Model (RZWQM2), which integrates crop growth-related processes. The objective of this study is to investigate the effect of the nitrogen application rate on crop growth, soil water dynamics, and ETc behavior under different rainfall amounts by using experimental data and the RZWQM2. A field study was conducted from 2016 to 2019 with three nitrogen application rates (0, 70 and 130 kg N ha−1) for unirrigated winter wheat (Triticum aestivum L.), and two nitrogen application rates (0 and 205 kg N ha−1) for unirrigated corn (Zea mays L.). For the period of 1986–2019, the amounts of actual rainfall during each crop growth period are categorized into four groups. Each rainfall group is used as a rainfall scenario in the RZWQM2 to explore the interactions between the rainfall amounts and N levels on the resulting crop growth and water status. The results show that the model satisfactorily captures the interaction effects of nitrogen application rates and rainfall amounts on the daily ETc and soil water dynamics. The nitrogen application rate showed a noticeable impact on the behavior of soil water dynamics and ETc components. The 75% rainfall scenario yielded the highest nitrogen uptake for both crops. This scenario revealed the highest water consumption for wheat, while corn showed the highest water uptake for the 100% rainfall scenario. The interaction between a high nitrogen level and 50% rainfall yielded the highest water use efficiency, while low nitrogen and 125% rainfall yielded the highest nitrogen use efficiency. A zero nitrogen rate yielded the highest ETc and lowest soil water content among all treatments. Moreover, the impacts of the nitrogen application rate on ETc behavior, crop growth, and soil water dynamics differed depending on the received rainfall amount.

scholarly journals Characteristics and Driving Factors of Nitrogen-Use Efficiency in Chinese Greenhouse Tomato Cultivation

2022 ◽  
Vol 14 (2) ◽  
pp. 805
Author(s):  
Tianjing Ren ◽  
Yu’e Li ◽  
Tiantian Miao ◽  
Waseem Hassan ◽  
Jiaqi Zhang ◽  
...  
Keyword(s):  
Nitrogen Use Efficiency ◽  
Organic Nitrogen ◽  
Organic Matter Content ◽  
Application Rate ◽  
Matter Content ◽  
Nitrogen Application ◽  
Nitrogen Use ◽  
Greenhouse Tomato ◽  
Use Efficiency ◽  
Nitrogen Application Rate

Excessive nitrogen fertilizer application in greenhouses could cause a significant variation in the nitrogen-use efficiency at the regional scale. This study aims to quantify agronomic nitrogen-use efficiency (AEN) and identify its driving factors across Chinese greenhouse tomato cultivation. Three hundred and forty-eight AEN values were obtained from 64 papers, including mineral nitrogen (MN) and mineral combined with organic nitrogen (MON) treatments. The average AEN values for the MN and MON treatments were 56.6 ± 7.0 kg kg−1 and 34.6 ± 3.5 kg kg−1, respectively. The AEN of the MN treatment was higher than that of the MON treatment for cultivation using soil with an organic matter content of less than 10 g kg−1 and the drip fertigation method. The AENs of the MN and MON treatments were divided into two segments according to the nitrogen application rate. The inflection points of the nitrogen application rate were 290 and 1100 kg N ha−1 for the MN and MON treatments, respectively. When the ratio of organic nitrogen to total nitrogen was less than 0.4, it was beneficial for improving the AEN. The soil organic matter content and the nitrogen application rate were the most critical factors determining the AEN. These results suggest that rationally reducing the nitrogen input and partially substituting mineral nitrogen with organic nitrogen can help improve the nitrogen-use efficiency.

scholarly journals Optimization of Nitrogen Fertilizer Application with Climate-Smart Agriculture in the North China Plain

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3415
Author(s):  
Jinsai Chen ◽  
Guangshuai Wang ◽  
Abdoul Kader Mounkaila Hamani ◽  
Abubakar Sunusi Amin ◽  
Weihao Sun ◽  
...  
Keyword(s):  
Nitrogen Use Efficiency ◽  
Nitrogen Fertilizer ◽  
Maize Yield ◽  
Application Rate ◽  
N2o Emissions ◽  
Nitrogen Application ◽  
Residual Concentration ◽  
Nitrogen Use ◽  
N Application ◽  
Use Efficiency

Long−term excessive nitrogen fertilizer input has resulted in several environmental problems, including an increase in N2O emissions and the aggravation of nitrate leaching; monitoring nitrogen fertilizer is crucial for maize with high yield. This study aimed to optimize the amount of nitrogen applied to maize by Climate−Smart Agriculture (CSA) so as to continuously improve agricultural productivity and reduce or eliminate N2O emissions as much as possible. Field experiments with a completely randomized design were conducted to examine the effects of six nitrogen treatments (N application levels of 0, 120, 180, 240, 300, 360 kg·ha−1, respectively) on N2O emissions, residual concentration of nitrate and ammonium nitrogen, maize yield, and nitrogen utilization efficiency in 2018 and 2019. The results indicated that the residual concentration of nitrate nitrogen (NO3-−N) in the two seasons significantly increased; N2O emissions significantly increased, and the nitrogen fertilizer agronomic efficiency and partial productivity of maize fell dramatically as the nitrogen application rate increased. The maize grain yield rose when the N application amount was raised (N application amount <300 kg·ha−1) but decreased when the N application amount > 300 kg·ha−1. An increase in the nitrogen application rate can decrease nitrogen use efficiency, increase soil NO3-−N residual, and N2O emissions. Reasonable nitrogen application can increase maize yield and reduce N2O emissions and be conducive to improving nitrogen use efficiency. By considering summer maize yield, nitrogen use efficiency, and farmland ecological environment, 173.94~178.34 kg N kg·ha−1 could be utilized as the nitrogen threshold for summer maize in the North China Plain.

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