Evaluation of Potential Productivity of Woody Energy Crops on Marginal Land in China

Energy crops are a basic material in the bioenergy industry, and they can also mitigate carbon emissions and have environ- mental benefits when planted on marginal lands. The aim of this study was to evaluate the potential productivity of energy crops on marginal lands in China. A mechanistic model, combined with energy crop and land use characteristics, and meteorological and soil parameters, was used to simulate the potential productivity of energy crops. There were three main results. 1） The total marginal land in China was determined to be 104.78 × 106 ha. The 400-mm precipitation boundary line, which is the dividing line between the semi-humid and semi-arid zones in China, also divided the marginal land into shrub land and sparse forest land in the southeast and bare land, bare rock land, and saline alkali land in the northeast. 2） The total area of the marginal land suitable for planting energy crops was determined to be 55.82 × 106 ha, with Xanthoceras sorbifolia and Cerasus humilis mainly grown in the northern China, Jatropha curcas and Comus wilsoniana mainly grown in the southwest and southeast, and Pistacia chinensis mainly grown in the central area, while also having a northeast-southwest zonal distribution. 3） Taking the highest yield in overlapping areas, the potential productivity of target energy crops was determined to be 32.63 × 106 t/yr. Without considering the overlapping areas, the potential productivity was 6.81× 106 t/yr from X. sorbifolia, 8.86× 106t/yr from C. humilis, 7.18 ×106t/yr from J. curcas, 9.55 × 106t/yr from P. chinensis, and 7.78 ×106 t/yr from C. wilsoniana.

Exploiting pattern and sustainable development of marginal lands in the Three Gorge Reservoir Areas

This paper studied the distribution and utilization status, reasonable exploitation patterns and potential productivity, and sustainable development of marginal lands in the Three Gorge Reservoir Areas. It has been pointed that problems of the soil fertility degradation, poor productivity in crop lands, natural disasters and environmental deterioration existed in all the exploited marginal lands. In order to maintain the sustainability of the marginal lands, following measure have been proposed: prohibiting cultivation in the crop lands with a slope more than 25°, restoring vegetation in the slope more than 25°, strengthening the basic agricultural construction, establishing the production base of woody feeds and oils, establishing a multi dimensional management model with reasonable structure and optimum function for forestry, agriculture and fishing.

Marginal land in China suitable for bioenergy crops under diverse socioeconomic and climate scenarios from 2020 to 2100

Maximizing the development of renewable energy plays a critical role in mitigating the climate crisis.Marginal land provides space for the development of biomass energy;however,it remains unclear how the amount and spatial distribution of marginal land that is suitable for energy crop development will change in the future.Here,we project energy marginal land changes in China following the shared socioeconomic pathway(SSP)and/or repre-sentative concentration path(RCP).We provide datasets of mar-ginal land,agriculturally suitable land,and potentially suitable for energy crops under historical scenarios and six future scenarios(i.e.SSP1-1.9,SSP1-2.6,SSP4-3.4,SSP2-4.5,SSP4-6.0,and SSP3-7.0)for the period 2020-2100,with a spatial resolution of 5 km.Under the six scenarios,from 2020-2100,the area of suitable marginal land ranged from 1.90-16.28(Jatropha curcas L.)to 37.37-73.97(Panicum virgatum L.)(×10^(4)km^(2)),depending on the choice of energy crops and climate scenario.Based on the growing suitability of eight important bioenergy crops-Ricinus communis L.,Saccharum officinarum L.,Pistacia chinensis Bunge,Panicum virga-tum L.,Jatropha curcas L.,Miscanthus giganteus J.,Manihot esculenta Crantz,and Sorghum bicolor Moench-our dataset can be used to identify suitable locations for specific energy crops.This new syn-thetic dataset could support the development of multiscenariobased solutions related to carbon neutrality,ecosystem services,and energy transition.

Salt-affected marginal lands:a solution for biochar production

The literature has shown that biochar can serve as potential amendment to achieve sustainable agriculture and environment.The accessibility and availability of cheap feedstock are considered as important constraint factors for the widespread application of biochar in agriculture.Marginal lands are widely distributed globally,several times larger than arable land,and hold little value for food production due to poor soil conditions.However,these lands are suitable for growing plants,which can be used as feedstock for biochar production.The salt-affected lands,as one of the main marginal lands,are particularly suitable for cultivating diverse varieties of halophytes that can be pyrolyzed into biochar,bio-gas,and bio-oil.The halophyte-derived biochar is useful to produce a desirable acid soil conditioner due to its high ash and rich bases,and improves soil characteristics under extreme saline conditions.Additionally,syngas and bio-oil hold potential benefits as fuels and industrial raw materials.This study introduces an innovative management technique for marginal lands such as salt-affected land,which can provide all-round benefits in food production,land management,vegetation coverage,carbon sequestration,and climate change mitigation.

Marginal land bioethanol production of sweet sorghum based on limited water resources in Northwest China

Sweet sorghum is considered a leading non-grain candidate for bioethanol production due to its low input requirement,good tolerance,high biomass potential,and high sugar content.However,insufficient studies have been conducted on the spatial distribution of sweet sorghum-based bioethanol production potential considering the water resources limitation.We presented a multi-factor analysis method not only considering terrain,meteorology,soil,and crop natural growth habits but also considering the local water resource to explore the available marginal land suitable for sweet sorghum cultivation and assess the bioethanol production potential in Northwest China.The results showed that 4.63×10^(7)hm^(2)available marginal land was suitable for sweet sorghum planting.Considering the constraint of local water resources,2.76×10^(6)hm^(2)available marginal land was suitable for sweet sorghum planting,accounting for 4.7%of the total available marginal land.And 1.23×10^(10)L bioethanol could be produced on it.Moreover,for these districts under low water stress levels,9.79×10^(5)hm^(2)available marginal land in Gannan Tibet AP and Longnan of Gansu and Hulun Buir of Inner Mongolia was considered a priority to develop sweet sorghum-based bioethanol,and 5.56×10^(9)L bioethanol could be produced in these districts,which can satisfy the 1.54%biofuel goal for 2050 of China.

Sustainable food production in marginal lands--Case of GDLA member countries

Sustainable food production in the changing climate and dwindling water resources in the Global Dry Land Alliance(GDLA)member countries is a real challenge,especially when considering marginal lands in dryland systems.The definition of marginal land is very vague and defined from different perspectives(pragmatism about marginal lands).Dryland itself indicates"marginality"due to water stress.In general,the abandoned agriculture land where food production is not economical,and has low inherent productivity potential is considered marginal;however,a land may be marginal for agriculture but vital for grazing.In this paper attempts have been made to give review of literature(water stress,extent of marginal saline lands,marginality).Policy matters(development of soil,water and agriculture strategies)that GDLA and member countries should consider for future sustainable food production in their countries,including but not limited to,assessment of land resources for agriculture potential,defining,mapping and characterizing marginal lands,and use of innovative technologies(conservation agriculture,climate smart agriculture,integrated soil reclamation program and capacity building)for food production,are discussed.The international perception(FAO,UNEP,CGIAR)on marginal lands is also described.An innovative approach of using national biocapacity and ecological footprint is used to assess marginality of GDLA member countries.Ecological overshoot(using 1.5 earth planets)and biocapacity debtor and creditor countries are highlighted.Challenges and best management practices for food production in marginal lands are included.Other important issues,like leasing land abroad,GDLA strategic food reserves and best management practices,innovative ideas for food production are shared.Finally recommendations are drafted for actions by GDLA,its member countries and the partners.

How profitable is switchgrass in Illinois, USA? An economic definition of marginal land

Background:Decisions regarding the conversion of land from an existing crop to bioenergy crops are critical for the sustainable production of both food and fuels.This study seeks to establish criteria for delineating land as“economically marginal”,and thus suited for growing switchgrass.Methods:In this case study of an Illinois agricultural field,the profitability of switchgrass,with farmgate prices of$44 Mg−1,$66 Mg−1,or$88 Mg−1,was compared to corn and soybean crop prices.Further,the study also evaluates the profitability of switchgrass when replacing corn‐based yield estimates from the Soil Productivity Index(SPI)of Illinois.Results:Based on a dry‐matter yield of 10.45 Mg ha−1,switchgrass can compete with soybeans only at the high price of$88 Mg−1,but depending on location,can compete with corn at$66 Mg−1.Across Illinois,at$88 ha−1,all Illinois land with SPI<100%and 95%of land under SPI class C(SPI 100–116)is profitable under switchgrass.Switchgrass may not be profitable relative to corn grown in the SPI class A(SPI>133)and only 7%of class B(SPI 117–132).Conclusions:Our results show that land with drainage and erosion limitations is economically marginal when corn and soybean yields are low,and the farmgate price for switchgrass is greater than$66 Mg−1.However,this may not be possible on land where switchgrass is replacing frequent soybean rotations(corn–soybean ratio≤1).Land used to produce only soybeans may only be marginal at the farmgate price of$88 Mg−1.Further studies need to be conducted to identify how much land can be converted to switchgrass without harming corn production.

Marginalization of Arable Land and its Correlation with Rural Labor Migration——A Case of Tongcheng County,Hubei Province,China

Based on the introduction of the connotation of marginalization,the index of diagnosing the marginalization degree is put forward.According to the 685 copies of questionnaires on peasant households in Tongcheng County of Hubei Province and the statistical data of local government,marginalization of arable land and its correlation with rural labor migration in Tongcheng County are studied by using aggregative indicator method,clustering analysis method and correlation analysis method.Result shows that marginalization of arable land has happened two times in Tongcheng County since 1985.Dry land has severer marginalization degree than paddy field.There is significant correlation between marginalization degree of arable land and rural labor migration;and the correlation between marginalization degree and rural labor migration in paddy field is greater than that in dry land.Marginalization of arable land will advance the rural labor migration,while in response to the poor current circulation of lands;the rural labor migration will further deepen the marginalization degree.Marginalization of arable land is one of the important factors affecting the labor migration in rural areas.

Nutrient coordination mechanism of tiger nut induced by rhizosphere soil nutrient variation in an arid area, China

Tiger nut is a bioenergy crop planted in arid areas of northern China to supply oil and adjust the planting structure.However,in the western region of Inner Mongolia Autonomous Region,China,less water resources have resulted in a scarcity of available farmland,which has posed a huge obstacle to planting tiger nut.Cultivation of tiger nut on marginal land can effectively solve this problem.To fully unlock the production potential of tiger nut on marginal land,it is crucial for managers to have comprehensive information on the adaptive mechanism and nutrient requirement of tiger nut in different growth periods.This study aims to explore these key information from the perspective of nutrient coordination strategy of tiger nut in different growth periods and their relationship with rhizosphere soil nutrients.Three fertilization treatments including no fertilization(N:P(nitrogen:phosphorous)=0:0),traditional fertilization(N:P=15:15),and additional N fertilizer(N:P=60:15)were implemented on marginal land in the Dengkou County.Plant and soil samples were collected in three growth periods,including stolon tillering period,tuber expanding period,and tuber mature period.Under no fertilization,there was a significant correlation between N and P contents of tiger nut roots and tubers and the same nutrients in the rhizosphere soil(P<0.05).Carbon(C),N,and P contents of roots were significantly higher than those of leaves(P<0.05),and the C:N ratio of all organs was higher than those under other treatments before tuber maturity(P<0.05).Under traditional fertilization,there was a significant impact on the P content of tiger nut tubers(P<0.05).Under additional N fertilizer,the accumulation rate of N and P was faster in stolons than in tubers(P<0.05)with lower N:P ratio in stolons during the tuber expansion period(P<0.05),but higher N:P ratio in tubers(P<0.05).The limited availability of nutrients in the rhizosphere soil prompts tiger nut to increase the C:N ratio,improving N utilization efficiency,and maintaining N:P ratio in tubers.Elevated N levels in the rhizosphere soil decrease the C:N ratio of tiger nut organs and N:P ratio in stolons,promoting rapid stolon growth and shoot production.Supplementary P is necessary during tuber expansion,while a higher proportion of N in fertilizers is crucial for the aboveground biomass production of tiger nut.

Bioenergy: Examining the Efficient Utilization of Agricultural Biomass as a Source of Sustainable Renewable Energy in Louisiana

The use of renewable energy is steadily being adopted as a mitigative measure for reducing greenhouse gas emissions. By assessing biomass production and consumption estimates from Louisiana parishes, this study examines the utilization of agricultural biomass as a convenient renewable energy source, and the potential of marginal lands for growing bioenergy crops in Louisiana. This was achieved by retrieving parish-level acreage production of some biofuel crops recorded in 2021 using the Quick Stats Database, to map out the spatial locations and distribution of the biofuel crops. To examine the potential of Louisiana’s marginal lands in bioenergy crop production, data was obtained from the Soil Survey Geographic (SSURGO) database and mapped-out according to the eight Land Capability Classes numbered I-VIII. The results of the mapped-out acreage data revealed that 25% of the 64 parishes including Morehouse recorded high corn production estimates, while 43%, such as East Carroll, recorded high soybean production. Meanwhile, cotton production estimates were relatively low, as recorded in only 9 parishes, with one parish, Tensas, having the highest acreage production of around 23,000. Although the identified marginal lands in parishes such as Allen and Vernon had no records of corn, soybean, or cotton production, the soil survey database revealed that these marginal lands have high nutrient soils like Alfisols, Entisols and Inceptisols with optimal nutrient balance essential for high yield bioenergy crop production. Hence, this paper highlights Louisiana’s agricultural biomass to be leveraged as sustainable renewable sources while adhering to clear production guidelines, biofuel sustainability certification, and internationally agreed sustainability criteria.

Achieving food security and high production of bioenergy crops through intercropping with efficient resource use in China

With high rates of food and nonrenewable fossil fuel consumption worldwide,we are facing great challenges in ensuring food and energy security to satisfy the world population.Intercropping,as an important and sustainable cropping practice in agroecosystems,has been widely practiced around the world.Many studies have shown that some plants can deliver high yields when intercropped with other plants.Here,we review the biological mechanisms in improving resource utilization efficiency and illustrate the practical application of intercropping in ensuring food and energy security through improving production.Identifying suitable energy plants for marginal land,land not suitable for food crops growth,is an effective strategy to acquire high production of bioenergy,thus removing competition between the use of land for food and energy.The effective application of intercropping provides a potential pathway for production of food crops and energy plants by improving resource use efficiency and resistance to environmental stress.