Double-cropping Field Research Articles

Paddy Rice Double-Cropping Field Monitoring via Vegetation Indices with Limited Ground Data—A Case Study for Thapanzeik Dam Irrigation District in Myanmar

This study investigated two popular satellite-derived vegetation indices (VIs), MODIS NDVI and EVI, as tools for monitoring crop growth at the Thapanzeik Dam irrigation district in Myanmar, where quality ground data are difficult to obtain. The time-series analysis for seasonal peak VIs presented a considerable improvement in paddy cultivation during 2001–2020 in the irrigation district during summer and monsoon. Fields outside the district had a much lower improvement ratio. Within the irrigation district, a canal with limited water supply was identified via peak and average VIs evaluation. The evaluation of precipitation impact on crop growth demonstrated an opposite impact on crop growth in summer and monsoon cultivations. Water is one of the limiting factors in summer in the irrigation district; thus, precipitation improves water conditions. However, water is not the limiting factor in monsoon; thus, extra water from precipitation, both hydraulically and meteorologically, negatively impacts crop growth. Compared to NDVI, EVI better captured crop growth in densely vegetated surfaces. Meanwhile, information degradation might have occurred with 250 m EVI, using 500 m blue-band reflectance as an input. Thus, the best vegetation index to use depends on the purpose of monitoring and the site situation.

Environmental factors contributing to variations in CO2 flux over a barley-rice double-cropping paddy field in the Korean Peninsula.

Understanding the CO2 flux over agricultural crop fields is critical because the temporal cycle is driven by both ecological environment and anthropogenic change. We analyzed the net ecosystem exchange of CO2 measured over a barley-rice double-cropping field using the eddy covariance method for 5years. We conducted gap-filling based on u*-threshold criteria and partitioned the net ecosystem exchange into gross primary production and respiration. The relative importance analysis of solar radiation, temperature, soil heat flux, soil water content, and vapor deficit revealed that solar radiation and temperature were the dominant contributors to net ecosystem exchange. The annual variation in the net ecosystem exchange followed a bimodal pattern driven by CO2 uptake by both barley and rice, displaying two negative peaks in late April and mid-August. The elongation stages of the crops exhibited the highest flux. Gross primary production and respiration were closely related to solar radiation and nighttime temperature, respectively. The relative importance of the other environmental variables was affected by the cultivation season and irrigation water. In the period of rice cultivation, respiration was approximately 3µmolm-2s-1 higher during rice drainage than during the flooded period. The accumulated net ecosystem production was estimated to be 315 gC m-2 and 349 gC m-2 for the barley and rice growing periods, respectively, and 649 gC m-2 for the annual total. These values are comparable with the results of other studies on barley-rice double-cropping fields.

Mapping the Northern Limit of Double Cropping Using a Phenology-Based Algorithm and Google Earth Engine

Double cropping is an important cropping system in China, with more than half of China’s cropland adopting the practice. Under the background of global climate change, agricultural policies, and changing farming practices, double-cropping area has changed substantially. However, the spatial-temporal dynamics of double cropping is poorly understood. A better understanding of these dynamics is necessary for the northern limit of double cropping (NLDC) to ensure food security in China and the world and to achieve zero hunger, the second Sustainable Development Goal (SDG). Here, we developed a phenology-based algorithm to identify double-cropping fields by analyzing time-series Moderate Resolution Imaging Spectroradiometer (MODIS) images during the period 2000–2020 using the Google Earth Engine (GEE) platform. We then extracted the NLDC using the kernel density of pixels with double cropping and analyzed the spatial-temporal dynamics of NLDC using the Fishnet method. We found that our algorithm accurately extracted double-cropping fields, with overall, user, and producer accuracies and Kappa coefficients of 95.97%, 96.58%, 92.21%, and 0.91, respectively. Over the past 20 years, the NLDC generally trended southward (the largest movement was 66.60 km) and eastward (the largest movement was 109.52 km). Our findings provide the scientific basis for further development and planning of agricultural production in China.

Evaluating nitrate transport and accumulation in the deep vadose zone of the intensive agricultural region, North China Plain

Evaluation of the nitrate transport process in the deep vadose zone (DVZ) is important for groundwater quality management, especially in intensive agricultural regions, such as the North China Plain (NCP). The NCP produces ~20% of the total food grain in China, owing to timely groundwater irrigation and excessive chemical N fertilizer applications, and faces severe groundwater environmental degradation. This study evaluated the potential impacts of intensive agriculture on groundwater quality by investigating nitrate accumulation and transport in the DVZ of wheat-maize double-cropping field based on sediment sampling (maximum depth of 45.2 m) over three sub-regions of the NCP. The results showed that legacy nitrate‑nitrogen (NO3−-N) accumulated in the DVZ ranged from 118.5 to 6302.8 kg N ha−1 across the NCP; it increased with depth at an average rate of ~157 kg ha−1 m−1. Nitrate transport and accumulation in the DVZ were spatially varied and mainly controlled by the DVZ sediment textures, in addition to water and nitrogen inputs from the ground surface. Coarse sediments retained lower soil water content, resulting in less nitrogen storage; however, they provided greater nitrate transport velocity. Higher transport velocities observed in the alluvial-proluvial fan allowed chemical N fertilizer to reach the water table. However, in other regions, nitrate transport velocities were lower than the water table decline rates, implying that groundwater quality may not have been impaired by chemical N fertilizer. Furthermore, a reductive environment was identified in some areas with fine sediments, indicating a favorable environment for denitrification in the DVZ. The findings of the current study could provide an important foundation for groundwater quality management in agricultural areas, such as the NCP and similar regions.

Estimating Gross Primary Productivity (GPP) over Rice–Wheat-Rotation Croplands by Using the Random Forest Model and Eddy Covariance Measurements: Upscaling and Comparison with the MODIS Product

Despite advances in remote sensing–based gross primary productivity (GPP) modeling, the calibration of the Moderate Resolution Imaging Spectroradiometer (MODIS) GPP product (GPPMOD) is less well understood over rice–wheat-rotation cropland. To improve the performance of GPPMOD, a random forest (RF) machine learning model was constructed and employed over the rice–wheat double-cropping fields of eastern China. The RF-derived GPP (GPPRF) agreed well with the eddy covariance (EC)-derived GPP (GPPEC), with a coefficient of determination of 0.99 and a root-mean-square error of 0.42 g C m−2 d−1. Therefore, it was deemed reliable to upscale GPPEC to regional scales through the RF model. The upscaled cumulative seasonal GPPRF was higher for rice (924 g C m−2) than that for wheat (532 g C m−2). By comparing GPPMOD and GPPEC, we found that GPPMOD performed well during the crop rotation periods but underestimated GPP during the rice/wheat active growth seasons. Furthermore, GPPMOD was calibrated by GPPRF, and the error range of GPPMOD (GPPRF minus GPPMOD) was found to be 2.5–3.25 g C m−2 d−1 for rice and 0.75–1.25 g C m−2 d−1 for wheat. Our findings suggest that RF-based GPP products have the potential to be applied in accurately evaluating MODIS-based agroecosystem carbon cycles at regional or even global scales.

Effects of fertilizer practice on fungal and actinobacterial cellulolytic community with different humified particle-size fractions in double-cropping field

Cellulose plays an important role in maintaining or improving soil carbon (C) cycling and soil fertility of paddy field. There had close relationship between functional cellulose genes (cbhI and GH48) with characterize of soil organic matter chemical components (fulvic acid and humic acid) and soil physical fractions. However, there is still limited information about how functional cellulose degradation response to long-term fertilizer management and their relative importance for C sequestration under the double-cropping rice paddy field in southern of China. Therefore, the objective of this study were investigated the effects of 34-years long-term fertilizer regime on community abundance of cbhI and GH48 genes in five soil particle-size fractions (> 2000 μm, 2000–200 μm, 200–50 μm, 50–2 μm and 2–0.1 μm) by using polarization magic angle spinning 13C nuclear magnetic resonance spectroscopy. The field experiment was included four different fertilizer treatments: chemical fertilizer alone (MF), rice straw and chemical fertilizer (RF), 30% organic manure and 70% chemical fertilizer (OM), and without fertilizer input as a control (CK). The results showed that distribution of soil humus and cellulolytic microbial community abundance was significant increased under long-term application of crop residue and organic manure condition. And the FA, HA and HM C contents in > 2000 μm and 2000–50 μm fractions with MF, RF and OM treatments were significant higher than that of CK treatment. Meanwhile, the alkyl C and Oalkyl C groups of FA and HA in > 2000 μm fraction with MF, RF, OM and CK treatments were higher than that of the other fractions. There had higher AL% and lower ARO% of FA and HA in different particle-size fractions with MF, RF, OM and CK treatments. The results indicated that abundance of cbhI and GH48 genes in different particle-size fractions with RF and OM treatments were significant increased, compared with CK treatment. There had significant positive correlation between soil humus C components (FA and HA) with abundance of cbhI and GH48 genes, and the o-alkyl C and AL% of FA were positively correlated with abundance of cbhI and GH48 genes. As a result, the community abundance of cbhI and GH48 genes were significant increased under combined application of crop residue and organic manure with chemical fertilizer condition.

A MODIS-based scalable remote sensing method to estimate sowing and harvest dates of soybean crops in Mato Grosso, Brazil

Large-scale agriculture in the state of Mato Grosso, Brazil is a major contributor to global food supplies, but its continued productivity is vulnerable to contracting wet seasons and increased exposure to extreme temperatures. Sowing dates serve as an effective adaptation strategy to these climate perturbations. By controlling the weather experienced by crops and influencing the number of successive crops that can be grown in a year, sowing dates can impact both individual crop yields and cropping intensities. Unfortunately, the spatiotemporally resolved crop phenology data necessary to understand sowing dates and their relationship to crop yield are only available over limited years and regions. To fill this data gap, we produce a 500 m rainfed soy (Glycine max) sowing and harvest date dataset for Mato Grosso from 2004 to 2014 using a novel time series analysis method for Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery, adapted for implementation in Google Earth Engine (GEE). Our estimates reveal that soy sowing and harvest dates varied widely (about 2 months) from field to field, confirming the need for spatially resolved crop timing information. An interannual trend toward earlier sowing dates occurred independently of variations in wet season onset, and may be attributed to an improvement in logistic or economic constraints that previously hampered early sowing. As anticipated, double cropped fields in which two crops are grown in succession are planted earlier than single cropped fields. This difference shrank, however, as sowing of single cropped fields occurred closer to the wet season onset in more recent years. The analysis offers insights about sowing behavior in response to historical climate variations which could be extended to understand sowing response under climate change in Mato Grosso.

Farmyard manure application and associated root proliferation improve the net greenhouse gas balance of Italian ryegrass – Maize double-cropping field in Nasu, Japan

In Japan, most cows are fed indoors, so cow manure must be carefully treated and used to manage soil fertility. The objective of this study was to compare the net greenhouse gas (GHG) balance (NGHGB) of Italian ryegrass – corn (maize) double-cropping fields receiving farmyard manure (FYM), slurry, or methane fermentation digestion liquid (MFDL). FYM, Slurry, MFDL, mineral fertilizer only (Fert.), and no-N control (Cont.) plots were set up in a randomized block design (n = 3). FYM, slurry, or MFDL was applied to meet the K requirement for forage production, and then mineral fertilizers were supplemented to meet the N and P requirements. From September 2017 to September 2020, C inputs as manure and crop residue, heterotrophic respiration (RH), and emissions of methane (CH4) and nitrous oxide (N2O) from soil were determined. The similarity of the total yields in FYM, Slurry, MFDL, and Fert. plots reflected judicious fertility management. However, the residue-C input of Italian ryegrass was 38% greater in FYM plots than in the other plots. Manure-C input decreased in the order of FYM > Slurry > MFDL plots. RH was greater in FYM and Slurry plots than in MFDL plots. Net ecosystem C balance (NECB) ([residue-C + manure-C] − [RH-C + CH4-C]) decreased in the order of FYM > Slurry > MFDL plots. N2O emission was greater in Slurry and MFDL plots than in FYM plots. Consequently, NGHGB ([CH4 and N2O emissions] − NECB) in terms of CO2 equivalent decreased in the order of MFDL > Slurry > FYM plots, so FYM application contributed most to GHG mitigation. Yield-scaled NGHGB was smallest in FYM plots owing to the synergy of the greatest residue-C and manure-C inputs, less N2O emission, and the achievement of a high enough yield, reflecting judicious fertility management based on manure and mineral fertilizer.

7-9 Study on the Nitrogen Dynamics in Italian Ryegrass and Corn Double-cropping Field Applied with Cattle Slurry and Fertilizer : Effects of cattle slurry and fertilizer on the growth and nitrogen uptake of the plants

7-9 Study on the Nitrogen Dynamics in Italian Ryegrass and Corn Double-cropping Field Applied with Cattle Slurry and Fertilizer : Effects of cattle slurry and fertilizer on the growth and nitrogen uptake of the plants

7-8 Study on the Nitrogen Dynamics in Italian Ryegrass and Corn Double-cropping Field Applied with Cattle Slurry and Fertilizer : Effects of cattle slurry and fertilizer on the inorganic nitrogen contents of soil and soil water

7-8 Study on the Nitrogen Dynamics in Italian Ryegrass and Corn Double-cropping Field Applied with Cattle Slurry and Fertilizer : Effects of cattle slurry and fertilizer on the inorganic nitrogen contents of soil and soil water

Preserving soil quality under irrigation in the Senegal River Valley

Soil quality under irrigation in the Senegal River Valley may become affected by salinization (Delta) and alkalinization (Middle Valley) processes. The salinity status of 158 irrigated rice fields in the Delta was measured with an electromagnetic conductivity meter. Double-cropped fields (two rice crops per year on the same field) were least saline (average horizontal reading: 0.6 dS/m), followed by single-cropped drained fields (1.6 dS/m), single-cropped non-drained fields (2.5 dS/m), non-cropped sites outside irrigation schemes (4.7 dS/m) and abandoned fields (5.7 dS/m). Results illustrated that when cultivating rice in the delta, the ponded water on the soil surface blocks capillary rise of salt from the water table. In the valley, the difference in the total amount of carbonates in 1:50 soil extracts between cultivated and non-cultivated sites was used as an indicator for alkalinization risk in 27 irrigation schemes. Highest rates of carbonate accumulation (0.65 meq HCO3-/(kg soil) per cropping season) and, therefore, greatest soil degradation risk were observed in schemes without drainage, compared to 0.10 meq HCO3-/(kg soil) per cropping season in schemes with good irrigation and drainage facilities. Plot and scheme level recommendations that may preserve soil quality under irrigation are presented.

Carbon dioxide evolution of an upland rice and barley, double cropping field in central Japan

AbstractCarbon dioxide evolution rates from a double cropping, upland rice and barley field were determined in central Japan from June 1992 to May 1994, and regression models were developed to predict soil respiration rate. Diurnal patterns of hourly soil respiration rates (SRh) showed a similar trend with those of soil surface temperatures. Daily soil respiration rate (SRd) obtained by integrating SRh varied from 0.3 to 15.6 g CO2m−2for the 2 years. In the summer cropping period, SRd was positively correlated with daily mean soil surface temperature and negatively correlated with volumetric water content in soil. Moreover, this relationship was able to be expressed as a multiple‐factor model with an Adj‐R2of 0.925. On the other hand, in the winter cropping period, SRd was able to be represented by a single factor model using soil surface temperature with an Adj‐R2of 0.854. Based on these relationships, seasonal changes in soil respiration rate were estimated. Total soil respiration rates in 1992 and 1993 estimated for the summer cropping period were 1260 g CO2m−2and 1094 g CO2m−2, and for the winter cropping period 624 g CO2m−2and 676 g CO2m−2, respectively. It was considered that the lower values during the summer cropping period in 1993 depended on lower soil surface temperature and higher soil water content.

Annual net primary production and efficiency of solar energy utilization in three double-cropping agro-ecosystems in Japan

Annual net production and utilization efficiency of solar energy conversion were studied in three double-cropping agro-ecosystems: upland rice-barley (R-B), peanut-wheat (P-W) and dentcorn-Italian ryegrass (C-I). The investigations were carried out in upland fields in Ibaraki Prefecture, central Japan, from June 1985 to May 1988. The average annual global solar radiation (GSR) recorded was 44–55 × 10 2 MJ m −2 during the 3 years. Annual net primary production was 24.4–25.3 MJ m −2 for the food crops (R-B, P-W) and 53.3 MJ m −2 for the forage crop (C-I), which was equivalent to 0.54 (R-B), 0.50 (P-W) and 1.20% (C-I) of GSR for the year including the fallow period. Of the total net energy fixed by the crops, ∼ 90% was harvested materials (H). The rest comprised litter (L), stubble and roots (SR), which may be utilized later after decomposition by soil microorganisms. Dry matter production for every 1.0 MJ of GSR absorbed is ∼ 1.0g dry matter for peanut, 1.3–1.5 g for cereal crops (R, B and W) and 2.0–2.3 g for forage crops (C and I). The annual net production and the efficiency of solar energy utilization were compared with various types of terrestrial ecosystems. Fertile, double-cropping fields in Japan were comparable to or higher in net production than a forest ecosystem.

Absence of take-all decline in double-cropped fields

Absence of take-all decline in double-cropped fields

Incidence of Arthropod Predators in Different Soybean Cropping Systems

The seasonal incidence of nabids, Nabis spp., big-eyed bugs, Geocoris spp., minute pirate bugs, Orius spp., and spiders was examined in conventional, drill-, and double-crop-planted soybean in two localities in eastern Virginia during 1979 and 1980. Population densities of these predators were not sufficiently abundant during the sampling period in 1979 to make statistical comparisons. During 1980, Nabis spp., primarily N. roseipennis Reuter, were significantly more numerous in conventional and drill-planted fields. Geocoris spp., primarily G. punctipes (Say), were significantly higher in conventionally planted fields in Westmoreland County and in drill-planted fields in Richmond County. At both locations, Geocoris were most abundant in the earliest planted fields and were not commonly encountered in double-cropped fields. There were significantly more spiders in the drill-planted fields in Richmond County, and a similar trend was apparent at the other sampling location. Other Arthropod predators commonly encountered in soybean fields included: Podisus maculiventris (Say), Stiretrus anchorago (F.), Hippodamia tredecimpunctata tibialis (Say), Hippodamia convergens Guer., Zelus spp., Sinea spp., Arilus spp., Chrysopa spp., and mantids. No comparisons between population densities in different soybean cropping systems were determined for these species. Population densities of predators in untreated soybean fields were significantly higher during the first six weekly sampling periods than densities in fields treated with disulfoton (1.2 kg of Al/ha) in the furrow at planting.