Improved representation of agricultural land use and crop management for large-scale hydrological impact simulation in Africa using SWAT+

To date, most regional and global hydrological models either ignore the representation of cropland or consider crop cultivation in a simplistic way or in abstract terms without any management practices. Yet, the water balance of cultivated areas is strongly influenced by applied management practices (e.g. planting, irrigation, fertilization, and harvesting). The SWAT+ (Soil and Water Assessment Tool) model represents agricultural land by default in a generic way, where the start of the cropping season is driven by accumulated heat units. However, this approach does not work for tropical and subtropical regions such as sub-Saharan Africa, where crop growth dynamics are mainly controlled by rainfall rather than temperature. In this study, we present an approach on how to incorporate crop phenology using decision tables and global datasets of rainfed and irrigated croplands with the associated cropping calendar and fertilizer applications in a regional SWAT+ model for northeastern Africa. We evaluate the influence of the crop phenology representation on simulations of leaf area index (LAI) and evapotranspiration (ET) using LAI remote sensing data from Copernicus Global Land Service (CGLS) and WaPOR (Water Productivity through Open access of Remotely sensed derived data) ET data, respectively. Results show that a representation of crop phenology using global datasets leads to improved temporal patterns of LAI and ET simulations, especially for regions with a single cropping cycle. However, for regions with multiple cropping seasons, global phenology datasets need to be complemented with local data or remote sensing data to capture additional cropping seasons. In addition, the improvement of the cropping season also helps to improve soil erosion estimates, as the timing of crop cover controls erosion rates in the model. With more realistic growing seasons, soil erosion is largely reduced for most agricultural hydrologic response units (HRUs), which can be considered as a move towards substantial improvements over previous estimates. We conclude that regional and global hydrological models can benefit from improved representations of crop phenology and the associated management practices. Future work regarding the incorporation of multiple cropping seasons in global phenology data is needed to better represent cropping cycles in areas where they occur using regional to global hydrological models.

Soil Bacterial Community in the Multiple Cropping System Increased Grain Yield Within 40 Cultivation Years

The shortage of land resources restricts the sustainable development of agricultural production. Multiple cropping has been widely used in Southern China, but whether the continuous planting will cause a decline in soil quality and crop yield is unclear. To test whether multiple cropping could increase grain yield, we investigated the farmlands with different cultivation years (10–20 years, 20–40 years, and >40 years). Results showed that tobacco-rice multiple cropping rotation significantly increased soil pH, nitrogen nutrient content, and grain yield, and it increased the richness of the bacterial community. The farmland with 20–40 years of cultivation has the highest soil organic carbon (SOC), ammonium nitrogen, and grain yield, but there is no significant difference in the diversity and structure of the bacterial community in farmlands with different cultivation years. The molecular ecological network indicated that the stability of the bacterial community decreased across the cultivation years, which may result in a decline of farmland yields in multiple cropping system> 40 years. The Acidobacteria members as the keystone taxa (Zi ≥ 2.5 or Pi ≥ 0.62) appeared in the tobacco-rice multiple cropping rotation farmlands, and the highest abundance of Acidobacteria was found in the farmland with the highest SOC and ammonium nitrogen content, suggesting Acidobacteria Gp4, GP7, GP12, and GP17 are important taxa involved in the soil carbon and nitrogen cycle. Therefore, in this study, the multiple cropping systems for 20 years will not reduce the crop production potential, but they cannot last for more than 40 years. This study provides insights for ensuring soil quality and enhancing sustainable agricultural production capacity.

Profitability Analysis of a Four Crop Based Cropping Pattern in Bogura Region of Bangladesh

Farmers in the Bogura region benefit significantly from the systematic use of crop rotation. The experiment was performed at the Shibganj, Bogura, in 2015-16 and 2016-17 to create a potato-Boro-radish-T. Aman rice crop sequence that would compete with the potato-Boro-T. Aman rice crop sequence. Primary objectives of the experiment were to determine the cost of producing enhanced Potato-Boro-Radish-T. Aman rice and compare it to current potato-boro-t. aman rice. There were two patterns: Current Cropping Pattern Potato (BARI Alu-8)-Boro (BRRI dhan 28)-T. Aman (BRRI dhan-49) and Alternative Cropping Pattern Potato (BARI Alu-25)-Boro (BRRI dhan 28) -Radish (Rocky)-T. Aman (BRRI dhan-57). The research revealed that an alternative cropping pattern required average crop duration of 315 days to complete one cycle in a year, implying that a four multiple cropping sequence was economically viable to replace the current cropping pattern. In terms of mean REY, the total grain/tuber yield was 42.80 t/ha/year, which was 66% greater than the current pattern (25.76 t/ha/year). The overall production efficiency (185.14 kg/ha/day), usage of land (86.16%), and engagement in the population (660 man-days/ha/year) of the alternative cropping pattern were 45, 7, and 41% higher, respectively, than the current cropping pattern. Alternative cropping patterns had the gross benefit of 274911 Tk./ha/year, indicating that they were sparingly sustainable. The alternative crop sequence also improved crop strength, growers' real understanding, technique, profits, and engagement. Furthermore, by trying to incorporate T. aman straw into soil with an alternative cropping pattern, it promotes soil health. As a result, farmers in Bangladesh's Bogura region may employ a different planting pattern on their variable land in order to boost production and profitability while also creating jobs.

Multiple Leveling for Paddy Field Preparation with Double Axis Rotary Tillage Accelerates Rice Growth and Economic Benefits

In the multiple cropping regions of southern China, straw returning has become a widely practiced agronomic measure for rice cultivation. However, excessive straw often leads to a high proportion of stubble in topsoil, which prolongs the leveling time of the paddy field and delays the transplanting date for rice seedlings. In particular, scholars in this region have successively improved multiple paddy field levelers to realize excellent straw returning and subsequent land preparation synchronously, but the economic benefit from land preparation to crop harvest was less reported. Therefore, this study carried out a 2-year rice cultivation experiments to compare the effects of paddy field preparation methods on rice growth and economic benefits within the same growing duration. Three treatments were designed: traditional tillage (TT), double axis rotary tillage (DR) and multiple operations for paddy field preparation (DR + ML), with three repeats. The results showed that DR + ML treatment simplified the operation process while improving the quality of land preparation. Within the same growing duration, DR + ML treatment could reduce the paddy field preparation time and extend the growing time in the field by 5–6 days. Furthermore, in comparison to TT treatment, DR + ML showed advantages in stimulating plant development, increasing dry matter accumulation (DMA), and thereby increasing rice yield by more than 12%. The economic benefits were mainly reflected in saving operation cost of paddy field preparation and improving the output (grain yield), which can generally increase the total profit by 58%. The implementation of this study can provide a reference for a simplified high yield cultivation technique in rice-related multiple cropping systems.

Dynamic Amazonia: The EU–Mercosur Trade Agreement and Deforestation

The trade agreement between the European Union and the Mercosur countries will increase deforestation in the Mercosur countries and Brazil, in particular, if ratified by member countries. We use a computable general equilibrium model to analyze how trade, land use, and agricultural production will change as a result of the agreement. We then use a statistical model to spatially allocate the predicted deforestation within the Brazilian Amazon. The models estimate that the agreement will cause additional deforestation in Brazil ranging from 56 to 173 thousand ha to accommodate increases in cropland area, depending on the level of governance, use of double-cropping techniques, and trade elasticity parameters. Most additional deforestation in Amazonia would be clustered near current deforestation hotspot areas. Some hotspots threaten the integrity of Indigenous lands and conservation units. Although a low deforestation scenario with gains in welfare is theoretically possible when high governance and multiple-cropping systems are in place, political challenges remain and cast doubt on Brazil’s ability to rein on illegal deforestation.

Soil bioengineering for sustainable coffee farming in Way Besai sub-watersheds, Lampung, Indonesia

Soil bioengineering is part of vegetative land conservation activities, including covering all use of plants to maintain the carrying capacity of the land. The sustainability of coffee farming achievement in the upstream watershed area is closely related to the application of soil bioengineering technology. This study conducted to identify the recent studies of soil bioengineering technology and its application in coffee farming toward increasing the land productivity in the upstream watershed. The research location is a smallholder coffee plantation upstream of the Way Besay sub-watershed, spread over 3 sub-districts, Air Hitam, Way Tenong, and Sumber Jaya sub-District, West Lampung, Lampung, Indonesia. Coffee farmers as many as 167 people as respondents. The data analysis method used exploration of the applicability of soil bioengineering technology at the micro-level. The mapping of the role of soil bioengineering trace using the VosViewer tool. The results of the analysis show that the readiness level application of soil bioengineering technology in coffee farming includes the production and use of organic fertilizers made from local materials, the use of mulch as soil cover, agroforestry with a variety of tall canopy plants/MPTS, the planting of multiple cropping (planting various yielding crops), and plant diversification with alley planting. Soil bioengineering technology has a very high potential to increase land productivity to support sustainable coffee production in the upstream area of the Lampung watershed.

GCI30: a global dataset of 30 m cropping intensity using multisource remote sensing imagery

The global distribution of cropping intensity (CI) is essential to our understanding of agricultural land use management on Earth. Optical remote sensing has revolutionized our ability to map CI over large areas in a repeated and cost-efficient manner. Previous studies have mainly focused on investigating the spatiotemporal patterns of CI ranging from regions to the entire globe with the use of coarse-resolution data, which are inadequate for characterizing farming practices within heterogeneous landscapes. To fill this knowledge gap, in this study, we utilized multiple satellite data to develop a global, spatially continuous CI map dataset at 30 m resolution (GCI30). Accuracy assessments indicated that GCI30 exhibited high agreement with visually interpreted validation samples and in situ observations from the PhenoCam network. We carried out both statistical and spatial comparisons of GCI30 with six existing global CI estimates. Based on GCI30, we estimated that the global average annual CI during 2016–2018 was 1.05, which is close to the mean (1.09) and median (1.07) CI values of the existing six global CI estimates, although the spatial resolution and temporal coverage vary significantly among products. A spatial comparison with two satellite-based land surface phenology products further suggested that GCI30 was not only capable of capturing the overall pattern of global CI but also provided many spatial details. GCI30 indicated that single cropping was the primary agricultural system on Earth, accounting for 81.57 % (12.28×106 km2) of the world's cropland extent. Multiple-cropping systems, on the other hand, were commonly observed in South America and Asia. We found large variations across countries and agroecological zones, reflecting the joint control of natural and anthropogenic drivers on regulating cropping practices. As the first global-coverage, fine-resolution CI product, GCI30 is expected to fill the data gap for promoting sustainable agriculture by depicting worldwide diversity of agricultural land use intensity. The GCI30 dataset is available on Harvard Dataverse: https://doi.org/10.7910/DVN/86M4PO (Zhang et al., 2020).

Adaptive Crop Management under Climate Uncertainty: Changing the Game for Sustainable Water Use

Water supplies are projected to become increasingly scarce, driving farmers, energy producers, and urban dwellers towards an urgent and emerging need to improve the effectiveness and the efficiency of water use. Given that agricultural water use is the largest water consumer throughout the U.S. Southwest, this study sought to answer two specific research questions: (1) How does water consumption vary by crop type on a metropolitan spatial scale? (2) What is the impact of drought on agricultural water consumption? To answer the above research questions, 92 Landsat images were acquired to generate fine-resolution daily evapotranspiration (ET) maps at 30 m spatial resolution for both dry and wet years (a total of 1095 ET maps), and major crop types were identified for the Phoenix Active Management Area. The study area has a subtropical desert climate and relies almost completely on irrigation for farming. Results suggest that there are some factors that farmers and water managers can control. During dry years, crops of all types use more water. Practices that can offset this higher water use include double or multiple cropping practice, drought tolerant crop selection, and optimizing the total farmed area. Double and multiple cropping practices result in water savings because soil moisture is retained from one planting to another. Further water savings occur when drought tolerant crop types are selected, especially in dry years. Finally, disproportionately large area coverage of high water consuming crops can be balanced and/or reduced or replaced with more water efficient crops. This study provides strong evidence that water savings can be achieved through policies that create incentives for adopting smart cropping strategies, thus providing important guidelines for sustainable agriculture management and climate adaptation to improve future food security.