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Rice Yield and the Fate of Fertilizer Nitrogen as Affected by Addition of Earthworm Casts Collected from Oilseed Rape Fields: A Pot Experiment

View Article: PubMed Central - PubMed

ABSTRACT

The mechanism associated with improvement of soil nutritional status by oilseed rape crop, leading to better performance of rice crop, in rice-oilseed rape cropping systems is little known. The present study was aimed to test the hypothesis that earthworm casts produced during oilseed rape-growing season have positive effects on grain yield and fertilizer nitrogen (N) utilization in the subsequent flooded rice crop. A 15N-tracing pot experiment was conducted to determine the effects of earthworm casts collected from oilseed rape fields on yield attributes in rice and the fate of fertilizer N. Soil treated with earthworm casts (soil: earthworm casts = 4: 1, w/w) (EC1) produced 39% higher grain yield than soil only (EC0). EC1 had 18% more panicle number and 10% higher spikelet filling percentage than EC0. Aboveground biomass and harvest index were higher in EC1 than in EC0 by 20% and 15%, respectively. SPAD values in flag leaves were 10% and 22% higher under EC1 than EC0 at 15 and 20 days after heading, respectively. EC1 had 19% higher total N uptake and 18% higher physiological N-use efficiency than EC0. These positive effects of earthworm casts on yield attributes offset negative effects of decreasing N rate from 0.74 g pot–1 (equivalent to the recommended field rate of 150 kg ha–1) to 0.44 g pot–1 (equivalent to 60% of the recommended rate). Fertilizer N retention rate was 7% higher while fertilizer N loss rate was 6% lower in EC1 than in EC0. Our study suggests that earthworm casts produced during oilseed rape-growing season are expected to have the following benefits on the subsequent flooded rice system: (1) improving growth and physiological processes in rice plants and consequently increasing rice grain yield, and (2) increasing fertilizer N retention rate and hence decreasing fertilizer N loss rate and reducing environmental risk.

No MeSH data available.


Related in: MedlinePlus

Oilseed rape fields for collecting earthworm casts in this study.(a) An earthworm in root-adhering soil of oilseed rape and (b) a pile of earthworm casts in an oilseed rape field.
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pone.0167152.g001: Oilseed rape fields for collecting earthworm casts in this study.(a) An earthworm in root-adhering soil of oilseed rape and (b) a pile of earthworm casts in an oilseed rape field.

Mentions: An outdoor pot experiment was conducted at the research farm of Hunan Agricultural University (28°11′N, 113°04′E), Changsha, Hunan Province, China in single rice-growing season (from May to October) in 2015. The soil used in the experiment, classified as an Ultisol (USDA taxonomy), was collected from the upper 20 cm of a rice paddy at the research farm. The tested earthworm casts was collected from oilseed rape fields located at Nanxian (29°21′N 112°25′E), Hunan Province (Fig 1). The chemical properties of the soil and earthworm casts were analyzed and shown in Table 1. The pH was determined by a digital pH meter, organic matter by the potassium dichromate method, total N by the semi-micro Kjeldahl method, available P by the Olsen method, and available K by an atomic absorption spectrophotometry [21]. The soil and earthworm casts were air-dried and sieved (5 mm) before use.


Rice Yield and the Fate of Fertilizer Nitrogen as Affected by Addition of Earthworm Casts Collected from Oilseed Rape Fields: A Pot Experiment
Oilseed rape fields for collecting earthworm casts in this study.(a) An earthworm in root-adhering soil of oilseed rape and (b) a pile of earthworm casts in an oilseed rape field.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120869&req=5

pone.0167152.g001: Oilseed rape fields for collecting earthworm casts in this study.(a) An earthworm in root-adhering soil of oilseed rape and (b) a pile of earthworm casts in an oilseed rape field.
Mentions: An outdoor pot experiment was conducted at the research farm of Hunan Agricultural University (28°11′N, 113°04′E), Changsha, Hunan Province, China in single rice-growing season (from May to October) in 2015. The soil used in the experiment, classified as an Ultisol (USDA taxonomy), was collected from the upper 20 cm of a rice paddy at the research farm. The tested earthworm casts was collected from oilseed rape fields located at Nanxian (29°21′N 112°25′E), Hunan Province (Fig 1). The chemical properties of the soil and earthworm casts were analyzed and shown in Table 1. The pH was determined by a digital pH meter, organic matter by the potassium dichromate method, total N by the semi-micro Kjeldahl method, available P by the Olsen method, and available K by an atomic absorption spectrophotometry [21]. The soil and earthworm casts were air-dried and sieved (5 mm) before use.

View Article: PubMed Central - PubMed

ABSTRACT

The mechanism associated with improvement of soil nutritional status by oilseed rape crop, leading to better performance of rice crop, in rice-oilseed rape cropping systems is little known. The present study was aimed to test the hypothesis that earthworm casts produced during oilseed rape-growing season have positive effects on grain yield and fertilizer nitrogen (N) utilization in the subsequent flooded rice crop. A 15N-tracing pot experiment was conducted to determine the effects of earthworm casts collected from oilseed rape fields on yield attributes in rice and the fate of fertilizer N. Soil treated with earthworm casts (soil: earthworm casts = 4: 1, w/w) (EC1) produced 39% higher grain yield than soil only (EC0). EC1 had 18% more panicle number and 10% higher spikelet filling percentage than EC0. Aboveground biomass and harvest index were higher in EC1 than in EC0 by 20% and 15%, respectively. SPAD values in flag leaves were 10% and 22% higher under EC1 than EC0 at 15 and 20 days after heading, respectively. EC1 had 19% higher total N uptake and 18% higher physiological N-use efficiency than EC0. These positive effects of earthworm casts on yield attributes offset negative effects of decreasing N rate from 0.74 g pot–1 (equivalent to the recommended field rate of 150 kg ha–1) to 0.44 g pot–1 (equivalent to 60% of the recommended rate). Fertilizer N retention rate was 7% higher while fertilizer N loss rate was 6% lower in EC1 than in EC0. Our study suggests that earthworm casts produced during oilseed rape-growing season are expected to have the following benefits on the subsequent flooded rice system: (1) improving growth and physiological processes in rice plants and consequently increasing rice grain yield, and (2) increasing fertilizer N retention rate and hence decreasing fertilizer N loss rate and reducing environmental risk.

No MeSH data available.


Related in: MedlinePlus