Estimation of maize straw production and appropriate straw return rate in China

Excessive use of chemical fertilizers in agricultural practices have demonstrated a significant impact on microbial diversity and community in soil by altering soil physical and chemical properties, thereby leading to a certain degree of soil salinization and nutritional imbalances. As an organic amendment, maize straw has been widely used to improve soil quality; however, its effect on the soil bacterial community remains limited in Calcarie-Fluvie Cambisols soil in semi-humid arid plateau of North China. In the present experiment, we investigated the effects of continuous straw utilization and fertilization on bacterial communities in Shouyang, Shanxi province, China. Soil samples were collected from 5 different straw utilization and fertilization modes in the following ways: straw mulching (SM), straw crushing (SC), cattle manure (CM), in which way straw is firstly used as silage and then organic fertilizer, control with no straw return (NSR), and control without fertilizers (CK), same amount of N+P fertilizer was applied to the regimes except CK. High-throughput sequencing approaches were applied to the V3-V4 regions of the 16S ribosomal RNA for analysis of the bacterial abundance and community structures. Different long-term straw returning regimes significantly altered the physicochemical properties and bacterial communities of soil, among which CM had the most significant effects on soil fertility and bacterial diversity. Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, and Gemmatimonadetes were consistently dominant in all soil samples, and Redundancy analysis (RDA) showed significant association of total nitrogen (TN), total phosphorus (TP) and available potassium (AK) with alternation of the bacterial community. Cattle manure had the most beneficial effects on soil fertility and bacterial diversity among different straw utilization and fertilization modes.

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Effects of Straw-Return Method for the Maize–Rice Rotation System on Soil Properties and Crop Yields

Agronomy ◽

10.3390/agronomy10040461 ◽

2020 ◽

Vol 10 (4) ◽

pp. 461

Author(s):

Yuling Han ◽

Wei Ma ◽

Baoyuan Zhou ◽

Xiaolong Yang ◽

Akram Salah ◽

...

Keyword(s):

Microbial Community ◽

Organic Carbon ◽

Rice Straw ◽

Soil Microbial Community ◽

Crop Yields ◽

Microbial Community Composition ◽

Soil Layer ◽

Soil Microbial ◽

Maize Straw ◽

Straw Return

Exploring suitable maize straw-return measures is essential for the new double-cropping system of maize (Zea mays L.)–rice (Oryza sativa L.) rotation in the middle reaches of Yangtze River in China, which can increase crop yield by improving soil quality. In this study, four straw-return measures were evaluated by investigating the soil bulk density (BD), organic matter (OM), microbial community, and nutrients from 2016 to 2018. The four straw-return treatments were as follows: (1) no straw-return (CK), (2) only rice straw incorporated into the field (M0Ri), (3) both maize and rice straw incorporated to field (MiRi), and (4) maize straw mulched and rice straw incorporated into the field (MmRi). Compared to CK, two-season crop straw-return treatments changed soil microbial community composition, and increased soil total organic carbon (TOC) and dissolved organic carbon (DOC), microbial biomass carbon (MBC), mineralized nitrogen (Nmin), available phosphorus (P) and exchangeable potassium (K) in the 0–20 cm soil layer by 3.6%, 63.4%, 38.8%, 12.4%, 39.7%, and 21.6%, respectively, averaged across MmRi and MiRi treatments. In addition, MmRi and MiRi increased annual yield by 9.1% and 15.2% in 2017 and 11.7% and 12.9% compared to CK in 2018, respectively. MmRi exhibited superiority in the soil microbial community, enzyme activities, DOC, MBC, Nmin, available P, and exchangeable K in contrast to MiRi. We concluded that MmRi is the best measure to implement for straw-return in maize–rice rotation systems.

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Estimation of the Effects of Maize Straw Return on Soil Carbon and Nutrients Using Response Surface Methodology

Pedosphere ◽

10.1016/s1002-0160(18)60024-4 ◽

2018 ◽

Vol 28 (3) ◽

pp. 411-421 ◽

Cited By ~ 4

Author(s):

Dongxing ZHOU ◽

Ye SU ◽

Yucui NING ◽

Guohua RONG ◽

Guangdong WANG ◽

...

Keyword(s):

Response Surface Methodology ◽

Soil Carbon ◽

Response Surface ◽

Maize Straw ◽

Straw Return

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Responses of Cereal Yields and Soil Carbon Sequestration to Four Long-Term Tillage Practices in the North China Plain

Agronomy ◽

10.3390/agronomy12010176 ◽

2022 ◽

Vol 12 (1) ◽

pp. 176

Author(s):

Suying Chen ◽

Peipei Yang ◽

Yuming Zhang ◽

Wenxu Dong ◽

Chunsheng Hu ◽

...

Keyword(s):

North China Plain ◽

North China ◽

C Sequestration ◽

Summer Maize ◽

Soil C ◽

Tillage Practices ◽

The North ◽

Maize Straw ◽

Straw Return

Current tillage practices in the important winter wheat–summer maize double cropping system of the North China Plain are under debate because of negative effects on soil quality and crop yield. Therefore, a long-term experiment was conducted from 2001 to 2018 to determine the effects of soil conservation practices on crop yield and soil quality. The treatments were imposed following maize harvest and prior wheat seeding, and were defined as follows: (1) moldboard ploughing (0–20 cm) following maize straw removal (CK); (2) moldboard ploughing (0–20 cm) following maize straw return (CT); (3) rotary tillage following maize straw return (RT); and (4) no tillage with maize straw covering the soil surface (NT). Wheat straw was chopped and spread on the soil in all treatments and maize seeded without prior tillage. Wheat yields were higher in CT than RT and NT treatments (p < 0.05); NT had 18% lower wheat yields than CT. No significant differences were found between treatments in summer maize yields. The soil organic carbon (SOC) content in the surface layer (0–5 cm) was higher in NT and RT compared to CT and CK. However, SOC content in the 10–20 cm and 20–30 cm layers was lower in NT and RT compared to CT and CK. Similarly, available phosphorus in the surface soil was higher in NT and RT than in CT and CK. but the opposite was true for the lower soil layers. SOC stocks (0–30 cm) increased in all treatments, and were initially faster in NT and RT than in CT and CK. However, SOC stocks were higher in CT than in other treatments at the end of the experiment. This finding indicates that no tillage and reduced tillage decreased both wheat yields and soil C sequestration over time; it also indicates that CT was the most robust in terms of crop yields and soil C sequestration.

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ANALISIS PORTOFOLIO INVESTASI PADA SAHAM LQ45 DENGAN METODE MEAN VARIAN SATU KONSTRAIN

Jurnal Varian ◽

10.30812/varian.v1i2.68 ◽

2018 ◽

Vol 1 (2) ◽

pp. 22-29

Author(s):

Gilang Primajati

Keyword(s):

Capital Markets ◽

Minimum Variance ◽

Return Rate ◽

Optimal Portfolio ◽

Portfolio Diversification ◽

Portfolio Risk ◽

Expected Return ◽

Positive Weight ◽

The Mean

In the capital markets, especially the investment market, the establishment of a portfolio is something that must be understood by investors. Portfolio formation by investors to maximize profits as much as possible by minimizing the risk of losses that may occur. Portfolio diversification is defined as portfolio formation in such a way that it can reduce portfolio risk without sacrificing returns. Optimal portfolio with efficient-portfolio mean criteria, investors only invest in risk assets only. Investors do not include risk free assets in their portfolios. The efficient variance portfolio is defined as a portfolio that has minimum variance among the overall possible portfolio that can be formed, at the same expected return rate. The mean method of one constraint variant can be used as the basis for optimal portfolio determination. The shares of LQ-45 used are shares of AALI, BBCA, UNVR, TLKM and ADHI. AALI shares received a positive weight of 7%, BBCA 48%, UNVR 16%, TLKM 26% and ADHI 3%

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