Reducing nitrogen surplus and environmental losses by optimized nitrogen and water management in double rice cropping system of South China

Cultivation of green manure (GM) crops in intensive cropping systems is important for enhancing crop productivity through soil quality improvement. We investigated yield sustainability, nutrient stocks, nutrient balances and enzyme activities affected by different long-term (1982–2016) green manure rotations in acidic paddy soil in a double-rice cropping system. We selected four treatments from a long-term experiment, including (1) rice-rice-winter fallow as a control treatment (R-R-F), (2) rice-rice-milkvetch (R-R-M), (3) rice-rice-rapeseed (R-R-R), and (4) rice-rice-ryegrass (R-R-G). The results showed that different GM rotations increased grain yield and the sustainable yield index compared with those of the R-R-F treatment. Compared with those of R-R-F, the average grain yield of early rice in R-R-M, R-R-R, and R-R-G increased by 45%, 29%, and 27%, respectively and that of late rice increased by 46%, 28%, and 26%, respectively. Over the years, grain yield increased in all treatments except R-R-F. Green manure also improved the soil chemical properties (SOM and total and available N and P), except soil pH, compared to those of the control treatment. During the 1983–1990 cultivation period, the soil pH of the R-R-M treatment was lower than that of the R-R-F treatment. The addition of green manure did not mitigate the soil acidification caused by the use of inorganic fertilizers. The soil organic matter (SOM), total nitrogen (TN) and total phosphorus (TP) contents and stocks of C, N and P increased over the years. Furthermore, GM significantly increased phosphatase and urease activities and decreased the apparent N and P balances compared with those in the winter fallow treatment. Variance partitioning analysis revealed that soil properties, cropping systems, and climatic factors significantly influenced annual grain yield. Aggregated boosted tree (ABT) analysis quantified the relative influences of the different soil properties on annual grain yield and showed that the relative influences of TN content, SOM, pH, and TP content on annual crop yield were 27.8%, 25.7%, 22.9%, and 20.7%, respectively. In conclusion, GM rotation is beneficial for sustaining high crop yields by improving soil biochemical properties and reducing N and P balances in acidic soil under double- rice cropping systems.

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Intervention of Climate Smart Agriculture Practices in Farmers Field to Increase Production and Productivity of Winter Maize in Terai Region of Nepal

Journal of the Institute of Agriculture and Animal Science ◽

10.3126/jiaas.v35i1.22514 ◽

2018 ◽

Vol 35 (1) ◽

pp. 59-66

Author(s):

J. J. Gairhe ◽

M. Adhikari

Keyword(s):

Climate Change ◽

Water Management ◽

Plant Density ◽

Cropping System ◽

Appropriate Technology ◽

Residue Management ◽

Zero Tillage ◽

Yield Attributes ◽

Wide Range ◽

Smart Agriculture

Climate change has been the burning issue in agriculture sector. The research world is focused on developing appropriate technology, innovations and concept to cope up this change. The Climate Smart Agriculture [CSA] has been adapted globally for cultivation and crop management in changing context without compromising yield and productivity. The CSA involves wide range altered techniques and innovations like using resilient varieties, water management, zero tillage, legumes incorporation, cover cropping, site specific fertilizer management, variation in planting date etc. Grounding on the similar practices and principles of CSA, the research in maize was conducted in 2014 in farmers' field of Eastern Nepal. Three progressive farmers with 1 hector of land were selected and Maize was cultivated using Zero tillage seed cum fertilizer driller tractor. This field experiment considers farmers as replication with six different treatments. All treatments differ to each other based on nutrient management, water management, residue management, tillage practice, crop establishment, and inclusion of legumes in the cropping system. Six treatments are coded as follows: Current Irrigated (CI), Improved Irrigated Low (IIL), Improved Irrigated High (IIH), Climate Smart Agriculture-Low (CSA-L), Climate Smart Agriculture-Medium (CSA-M), and Climate Smart Agriculture-High (CSA-H). Significant impact of intervention was observed in yield and yield attributes in the trial with climate smart agriculture practices than in conventional practices of farmers. Plant density, ear number, filled grains per cob and grain yield was substantially higher in climate smart practices revealing CSA to be the appropriate technology to minimize potential loss of climate change.

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Medium-term effects of different types of N fertilizer on yield, apparent N recovery, and soil chemical properties of a double rice cropping system

Field Crops Research ◽

10.1016/j.fcr.2019.02.012 ◽

2019 ◽

Vol 234 ◽

pp. 87-94 ◽

Cited By ~ 7

Author(s):

Wenhai Mi ◽

Qiang Gao ◽

Siqi Xia ◽

Haitao Zhao ◽

Lianghuan Wu ◽

...

Keyword(s):

Chemical Properties ◽

Cropping System ◽

N Fertilizer ◽

Soil Chemical Properties ◽

N Recovery ◽

Medium Term ◽

Different Types ◽

Apparent N Recovery ◽

Double Rice

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Substitution of Inorganic Nitrogen Fertilizer with Green Manure (GM) Increased Yield Stability by Improving C Input and Nitrogen Recovery Efficiency in Rice Based Cropping System

Agronomy ◽

10.3390/agronomy9100609 ◽

2019 ◽

Vol 9 (10) ◽

pp. 609 ◽

Cited By ~ 3

Author(s):

Qaswar ◽

Jing ◽

Ahmed ◽

Shujun ◽

Dongchu ◽

...

Keyword(s):

Crop Yield ◽

Green Manure ◽

Inorganic Nitrogen ◽

Cropping System ◽

N Fertilization ◽

Yield Stability ◽

N Fertilizer ◽

Yield Variability ◽

Variability Index ◽

Double Rice

A long-term field experiment was carried out (since 2008) for evaluating the effects of different substitution rates of inorganic nitrogen (N) fertilizer by green manure (GM) on yield stability and N balance under double rice cropping system. Treatments included, (1) N0 (no N fertilizer and no green manure); (2) N100 (recommended rate of N fertilizer and no green manure); (3) N100-M (recommended rate of N fertilizer and green manure); (4) N80-M (80% of recommended N fertilizer and green manure); (5) N60-M (60% of recommended N fertilizer and green manure); and (6) M (green manure without N fertilization). Results showed that, among all treatments, annual crop yield under N80-M treatment was highest. Crop yield did not show significant differences between N100-M and N80-M treatments. Substitution of different N fertilizer rates by GM reduced the yield variability index. Compared to the N0 treatment, yield variability index of early rice under N100-M, N80-M, and N60-M treatments was decreased by 11%, 26%, and 36%, respectively. Compared to the N0 treatment, yield variability index of late rice was decreased by 12%, 38%, 49%, 47%, and 24% under the N100, N100-M, N80-M, N60-M, and M treatments, respectively. During period of 2009–2013 and 2014–2018, nitrogen recovery efficiency (NRE) was highest under N80-M treatment and N balance was highest under N100 treatment. NRE of all treatments with GM was increased over the time from 2009–2013 to 2014–2018. All treatments with GM showed increasing trend of SOC over the years. Substitution of N fertilizer by GM also increased C inputs and soil C:N ratio compared to the N100 and N0 treatments. Boosted regression model indicated that C input, N uptake and AN were most influencing factors of crop yield. Thus, we concluded that N fertilization rates should be reduced by 20% under GM rotation to attain high yield stability of double rice cropping system through increasing NRE and C inputs.

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