Alternative Cropping Systems Research Articles

Wide-strip intercropping of cotton and peanut combined with strip rotation increases crop productivity and economic returns

Cotton/peanut intercropping and their rotation have been widely studied and adopted in many cotton and peanut growing countries including China. However, it is impossible to harvest two crops in the same year under the cotton/peanut rotation. And continuous cropping constraints as indicated by inhibited crop growth and development as well as yield decline remain under continuous cotton/peanut intercropping. We hypothesized that a combination of intercropping and rotation can resolve these constraints or challenges. In a preliminary experiment, the traditional intercropping (TIC) of cotton and peanut was established and studied using monocultures of cotton (MC) or peanut (MP) as the control. Field experiments were then conducted to develop an alternate intercropping (AIC) of wide-strip cotton/peanut intercropping in combination with strip rotation (strips of the two crops were grown inter-annually in an alternate manner). Crop productivity, leaf photosynthesis, dry matter accumulation and partitioning, and main nutrient uptake as well as input-output and net returns of the new system were evaluated as compared with TIC, MC and MP for two consecutive years. Results showed that crop productivity varied significantly with cropping systems. On average, the TIC increased seed cotton yield by 16.9% and decreased peanut yield by 5.6%, while the AIC increased cotton yield by 21% without sacrificing peanut yield. The AIC increased the biological yield of peanut by 3.8% and harvest index by 2.4%; it increased the biological yield of cotton by 3.8% compared to TIC. AIC increased uptake of N, P and K in peanut by 6.3, 11.5 and 7.3%, as well as net photosynthetic rate, chlorophyll content and maximum leaf area index of peanut by 7.2, 8.9 and 4.4%, respectively, relative to TIC. Crop output value under AIC was 4.5% higher than that under TIC but the input value was the same; thus the net return under AIC exceeded that under TIC by 10%. The AIC increased crop productivity and economic return without additional input compared to traditional intercropping, thus is a promising alternative cropping system in the Yellow River valley and other areas with similar ecology.

Corn (Zea mays L.): A low methylmercury staple cereal source and an important biospheric sink of atmospheric mercury, and health risk assessment

In mercury (Hg) contaminated areas of Asia, human exposure to toxic methyl-Hg (MeHg) through a rice-based diet of locally produced crop may pose a health threat. Alternative cropping system to rice in such areas would be most desirable. In this study, corn, the leading cereal source in the world with large biomass, was demonstrated to accumulate an insignificant amount of MeHg from the soil in its edible portion compared to that in rice, suggesting corn being a very competitive alternative crop. By examining Hg stable isotope composition, Hg in the aerial parts of corn was found to be mostly from the atmosphere. Maize cropping worldwide is estimated to be a discemible sink of atmospheric Hg with approximately 44 Mg Hg accumulated in each growing season on a yearly basis, most of which is from foliar uptake of atmospheric Hg and this amount is comparable to litterfall Hg observed in North America and Europe. It is thus recommended to use corn as a replacement of rice in highly Hg-contaminated areas for remediation of Hg pollution in the food supply.

The Role of Agricultural Land Use Pattern Dynamics on Elephant Habitat Depletion and Human-Elephant Conflict in Sri Lanka

The drastic depletion of elephant habitats in the dry zone of Sri Lanka has led to intense human-elephant conflict (HEC) in a region that is home to one of the celebrated agrarian settlements in Asia. Known as the tank villages, these settlements have a long history of human coexistence with elephants and other wild animals. However, the escalating incidence of human-elephant fatalities and crop losses to farmers indicates that the mode of interaction between the tank village inhabitants and the elephants has transformed from coexistence to conflict. Both population and agricultural land use pattern dynamics have contributed to agricultural expansion and loss of elephant habitat in the dry zone of Sri Lanka. However, our knowledge of how the agricultural land use pattern dynamics has contributed to the drastic depletion of elephant range in the dry zone is limited. This research attempted to gain insight into the role of agricultural land use dynamics on elephant habitat depletion and HEC in Sri Lanka through the study of Kuttikulama, a dry zone tank village. The data were collected through focus group discussions, key informant interviews and a cross sectional survey. The study revealed that agricultural land use patterns in traditional dry zone villages have changed in major ways over the last few decades. Such changes included the transition from a shifting-cultivation mode of farming to a fixed sequential mode of farming, the expansion of the per capita cropping area, and the disappearance of communality in agricultural land use patterns. The changes were found to have significantly contributed to a shift in human–elephant interactions from relatively harmonious ones to contentious ones. The study reveals the potential of traditional and alternative cropping and land use systems to minimize human-elephant conflict in Sri Lanka.

Can alternative cropping systems mitigate nitrogen losses and improve GHG balance? Results from a 19-yr experiment in Northern France

Alternative cropping systems are promoted to reduce nitrogen (N) losses in the environment and mitigate greenhouse gas (GHG) emissions. However, these supposed benefits are not fully known, rarely studied together and on the long-term. Here, we studied the N inputs, N exports, soil organic N (SON) storage, N leaching, gaseous N emissions and GHG balance in a 19-yr field experiment comparing four arable cropping systems without manure fertilization, under conventional (CON), low-input (LI), conservation agriculture (CA) and organic (ORG) managements. The N surplus, i.e. the difference between total N inputs and exports, was lowest in LI (43 kg ha−1 yr−1), intermediary for CON and ORG with 63 kg ha−1 yr−1 and highest in CA (163 kg ha−1 yr−1). CA and ORG received high amounts of N derived from biological fixation from alfalfa. The annual SON storage rates markedly differed between CA (55 kg ha−1 yr−1) and both CON and LI (13 and 6 kg ha−1 yr−1), with intermediary value in ORG (30 kg ha−1 yr−1). N leaching, calculated using soil mineral N measurements, reached an average of 21 kg ha−1 yr−1 and did not significantly differ between treatments. The gaseous N emissions (volatilization + denitrification), calculated as the difference between N surplus, SON storage and N leaching, ranged from 12 kg ha−1 yr−1 in ORG to 83 kg ha−1 yr−1 in CA. N2O emissions were continuously monitored with automatic chambers during 40 months. They varied from 1.20 kg ha−1 yr−1 in LI to 4.09 kg ha−1 yr−1 in CA system and were highly correlated with calculated gaseous N emissions. The GHG balance, calculated using SOC and N2O measurements, varied widely between systems: it was highest in CON and LI, with 2198 and 1763 kg CO2eq ha−1 yr−1 respectively. In CA, the GHG balance was much more favourable (306 kg CO2eq ha−1 yr−1), despite important N2O losses which partly offset the benefit of SOC storage. ORG was the system with the smallest GHG balance (−65 kg CO2eq ha−1 yr−1), acting as a CO2 sink in the long-term. Similar trends were observed when GHG was expressed per unit of N input or N exported. The N surplus alone was not a good indicator of the N fate in the four agricultural systems. Complementary predictors of N losses and GHG balance are required to obtain a true overview of the C and N environmental impacts of cropping systems. On an operational point of view, these results should lead to investigate the variability of the GHG emissions within each cropping system.

Herbaceous perennial biomass production on frequently saturated marginal soils: Influence on N2O emissions and shallow groundwater

Warm season perennial grasses grown for biomass have been suggested as alternative cropping systems on marginal soils to increase farm profit, reduce nitrous oxide (N2O) emissions, and improve water quality. The objectives of this study were to determine: 1) how warm season perennial grasses, switchgrass (Panicum virgatum) and Miscanthus (Miscanthus x giganteus), compare to cool season grasses as streamside buffers on poorly drained marginal soils 2) if inorganic or organic nutrient additions improve biomass yield and affect environmental outcomes? 3) which soil variables influence N2O emissions in situ? We measured soil N2O emissions, soil solution nitrate (NO3−), ammonium (NH4+), O2, moisture, and temperature, along with shallow groundwater NH4+, NO3−, and ortho-phosphate during two growing seasons (2012–2013). N2O emissions were similar across unfertilized warm season grasses and cool season grasses. However, when switchgrass was fertilized with ammonium sulfate or broiler manure, N2O emissions increased significantly. N2O emissions were weakly correlated with soil solution NO3− concentrations and water filled pore space. Shallow groundwater N was elevated under switchgrass fertilized with ammonium sulfate, broiler manure, and when grown with the legume (Desmodium canadense) when compared to unfertilized switchgrass, Miscanthus, and cool season grasses. In 2013 dry aboveground biomass production did not differ among switchgrass treatments which averaged 10 Mg ha. Biomass production was significantly higher for Miscanthus (18.5 Mg ha). The results indicate that unfertilized switchgrass and Miscanthus are as effective as cool season grasses at mitigating N2O emissions and improving water quality, and that Miscanthus has potential production advantages over switchgrass grown on frequently saturated soils.

Understanding the Long-Term Weed Community Dynamics in Organic and Conventional Crop Rotations Using the Principal Response Curve Method

AbstractWeeds have acquired evolutionary adaptations to the diverse crop and weed management strategies used in cropping systems. Therefore, changes in crop production practices such as conventional to organic systems, tillage-based to no-till systems, and diversity in crop rotations can result in differences in weed community composition that have management implications. A study was carried out to understand the weed community dynamics in a long-term alternative cropping systems study at Scott, SK, Canada. Long-term (18-yr) weed community composition data in wheat (Triticum aestivumL.) in ORG (organic), RED (reduced-input, no-till), and HIGH (high-input, conventional tillage) systems with three levels of crop rotation diversity, LOW (low diversity), DAG (diversified annual grains), and DAP (diversified annuals and perennials), were used to study the effect of different cropping systems and the effect of environment (random temporal effects) on residual weed community composition using the principal response curve (PRC) technique. The interaction between cropping systems and year-to-year random environmental changes was found to be the predominant factor causing fluctuations in weed community composition. Furthermore, the single most predominant factor influencing the weed composition was year-to-year random changes. Organic systems clearly differed from the two conventional systems in most years and had more diverse weed communities compared with the two conventional systems. The two conventional systems exhibited similar weed composition in most years. In this study, the use of the PRC method allowed capture of the real temporal dynamics reflected in the cropping systems by time interaction. This study further concludes that moving from a tillage-based, high-input conventional system to a no-till, reduced-input system did not cause significant changes in the weed community composition throughout the time period, but diversity in organic systems was high, probably due to increased occurrence of some difficult to control species.

Alternative Cropping Systems with Limited Irrigation

Alternative Cropping Systems with Limited Irrigation

Growth and Yield of Upland Rice Under Intercropping System with Soybean in Sandy Coastal Area

Sandy coastal area in Indonesia is potential for upland rice cultivation, but it has constraints low of nutrient availability such as nitrogen. To solve the low fertility of the sandy land can be done by planting soybean between upland rice under intercropping system due to the soybean is able to provide nitrogen in soil through fixation of N2 in the air by root nodules. Intercropping is an alternative cropping system to increase land productivity, but there is competition between crops under an intercropping system. Reducing of the competition on the system is needed by crops proportion adjustment. The objective of the study is to examine growth and yield component of upland rice at different crops proportion under an intercropping system with soybean in the sandy coastal area. The research was conducted in Samas sandy coastal area, Bantul, Yogyakarta. This research used randomized complete block design (RCBD) with one factor and three blocks. The treatment of this research was five level crops proportion between upland rice and soybean under intercropping system, namely: 100:0; 80:20; 60:40; 40:60; and 20:80, respectively. The results showed that crop growth rate and yield per clump of upland rice increased on crops proportion adjustment under intercropping system with soybean. The crops proportion of 60:40 and 40:60 gave higher crop growth rates that were 1.45 g.dm-2.wk-1 and 1.44 1.45 g.dm-2.wk-1 than upland rice under monoculture (100:0) that was 1.09 g.dm-2.wk-1. The higher crop growth rates in crops proportion of 60:40 and 40:60 were able to give better yield per clump than other that were 17.17 g and 16.46 g, respectively. The yield of upland rice was not different under crops proportion of 100:0, 80:20, and 60:40 and decreased of upland rice proportion until ≤ 40% affected the low yield of upland rice.

Climate change, agricultural inputs, cropping diversity, and environment affect soil carbon and respiration: A case study in Saskatchewan, Canada

Climate change, agricultural inputs, cropping diversity, and environment have seldom been combined in analyses of soil organic carbon (SOC), and soil C respired through microbial respiration (MR). This modeling study assessed SOC and MR simulated with the Environmental Policy Integrated Climate (EPIC) model for historical weather (1971–2000) and future climate scenarios (2041–2070) for the Alternative Cropping Systems (ACS) study research site in Saskatchewan, Canada. Nineteen years of field and crop management information from the 1994–2013 ACS study were used to validate and provide parameters to the EPIC model for analyses of climate change scenarios. The ACS study consisted of three levels of agricultural inputs [organic (ORG), reduced (RED), and high (HI)] and three levels of cropping diversity [low (LOW), diversified annual grains (DAG), and diversified annuals and perennials (DAP)]. Changes in future SOC and MR under climate change were explored with ANOVA and recursive partitioning in multivariate analyses of inputs, diversity, growing season precipitation (GSP), growing degree days (GDD), annual average maximum, minimum temperatures, cumulative annual precipitation, and terrain attributes (TA). Under climate change, SOC decreased by 1.3% (from 132.3 to 130.6 Mg ha−1) of original stocks in the 0–90 cm. Microbial respiration was affected by climate change and increased by 17% (from 1.92 to 2.25 Mg C ha−1 y−1) due to an increase in annual maximum and minimum temperatures. The increase in annual maximum and minimum temperature was correlated with 32 and 42% of variation in SOC respectively. Monthly growing season GDD was correlated with 14% of variation of SOC in an analysis independent of annual data. Annual precipitation did not affect SOC, though May GSP accounted for 16% of total variation in SOC, while June temperature accounted for 9% of variation in MR. The combination of input and diversity was correlated with 3 and 7% of variation in SOC and MR, respectively. The combination of RED inputs and DAG diversity are the best option to manage SOC and reduce the amount of soil C respired under climate change relative to organic and conventional systems.

Impact of different cropping systems and irrigation schedules on evapotranspiration, grain yield and groundwater level in the North China Plain

Water shortage is the most limiting factors for the crop production in the North China Plain (NCP). The alternative cropping systems and the water-saving irrigation schedules are the main measures to reduce the groundwater level decline. In this study, APSIM model was used to simulate the effects of four different cropping systems (winter wheat and summer maize cropping system (WW-SM); winter wheat cropping system (WW); summer maize cropping system (SM); winter wheat –summer maize – spring maize cropping systems (WW-SM-sM)) under four different irrigation schedules (normal irrigation (NI); critical irrigation (CI); minimum irrigation (MI); and rain-fed (RF)) on evapotranspiration (ET), water use efficiency (WUE) groundwater table level and crop water productivities in the NCP. Results showed that the WW-SM cropping system had the higher grain yield and ET under NI, CI, MI, and RF conditions. Grain yield reduction (GYR) was decreased with the irrigation amount decreased for the WW cropping system, SM cropping system, and WW-SM-Sm cropping systems which ranged from 21.59% to 48.11%, from 16.71% to 46.93%, from 15.82% to 43.92%, and from 5.09% to 27.22% under the NI, CI, MI and RF irrigation schedules, respectively. For WUE and the economic water use efficiency (WUEe), WW-SM and WW-SM-sM had the higher value, WW and SM had the lower value. The differences for the different cropping systems were mostly caused by the grain yield and the soil evaporation. Meanwhile, the water-saving irrigation schedules and cropping systems both could reduce the groundwater table decline compared to that under normal irrigation and traditional cropping system. There all had the significant impact on groundwater table changes for both the irrigation schedules and cropping systems. However, water restriction will lead to crop yield reduction and water saving depending on the chosen alternative cropping systems and irrigation schedules. Results strongly suggest that the critical irrigation and WW-SM-sM cropping system could mitigate the groundwater over-exploitation and ensure the food safety in the NCP.

The profitability of diverse crop rotations and other cultural methods that reduce wild oat (Avena fatua)

With the increasing resistance of wild oat (Avena fatua L.) to herbicides, there is a need to evaluate the potential of alternative cropping systems based on integrated weed management principles. A 5-yr field study at eight sites across Canada was used to evaluate the profitability of alternative cropping systems that have the potential to control wild oat using cultural practices in conjunction with herbicides. Cultural practices included twice the recommended seeding rates, fall-seeded winter crops, barley (Hordeum vulgare L.) silage, fallow, and alfalfa (Medicago sativa L.). Seven of the 14 cropping systems in this study did not include wild oat herbicide for three consecutive years, controlling wild oat entirely by cultural practices. Cropping system profitability varied by location. For many locations, combinations of barley silage and fall-seeded winter crops without wild oat herbicide application were as profitable as a system of canola (Brassica napus L.) and wheat (Triticum aestivum L.) with wild oat herbicide applied every year. Unprofitable systems generally included those with fallow, alfalfa, and fall-seeded winter crops in regions with rates of high winter kill. Wild oat control can be achieved with diverse cropping systems that are as profitable as conventional annual cropping that relies on herbicide control of wild oat.

Review: Challenges and opportunities for revitalising smallholder irrigation schemes in South Africa

South Africa is classified as a water-scarce country, and depends on agriculture for food production. The irrigation sector is the largest consumer of water in the country, accounting for about 62% of water utilisation, but also losing 30–40%. Given the threat of drought and climate change, efficient irrigation systems have become a necessity, especially in the smallholder farming sector where most losses occur. Smallholder irrigation schemes (SIS) were developed to improve rural livelihoods through sustainable food production for food security and poverty alleviation, but these development objectives remain largely unfulfilled. The objectives of this review were to assess challenges facing SIS and explore opportunities for revitalising the schemes. The focus was on government policy and strategies to support smallholder farmers. A review of government policy showed that although the needs and interests of smallholder farmers are high on the national agenda, there is insufficient financial support to the sector, suggesting that smallholder agriculture is not really seen as a potential driver of the economy. The core focus of the government on repairing irrigation infrastructure while neglecting the soft components relating to capacity building has partly been blamed for the failure of SIS in South Africa. Capacity building is one of the missing links in smallholder irrigation development and many failures have been attributed to lack of adequately trained farmers and extension staff, particularly in irrigation water management. Land tenure insecurity has been singled out as a major institutional challenge leading to poor performance of irrigation schemes. The diversity of schemes means that different kinds of interventions are needed to respond to varying farmers’ needs, resources and agricultural contexts. These findings point to the need to balance the soft and hard components of the irrigation schemes for sustainability. It is therefore evident that the government needs to review its priorities in revitalisation of SIS. Land tenure policies allowing increased access to arable land need to be developed urgently, together with the promotion of alternative cropping systems that are suitable forthe smallholder farming sector.

Trade-offs and synergies between yield, labor, profit, and risk in Malawian maize-based cropping systems

Land degradation, population growth, and chronic poverty in Eastern and Southern Africa challenge the sustainability of livelihoods for smallholder farmers. These farmers often manage soils depleted of nutrients, apply limited amounts of mineral fertilizer, and take decisions about their cropping systems that involve multiple trade-offs. The rotation of cereals with legumes bears agronomic and ecological merit; however, the socio-economic implications of the cereal-legume rotation require a deeper understanding. This study explores the yield, labor, profit, and risk implications of different legume and mineral fertilizer practices in maize-based cropping systems in central Malawi. Our method involves coupling crop modeling and an agricultural household survey with a socio-economic analysis. We use a process-based cropping systems model to simulate the yield effects of integrating legumes into maize monocultures and applying mineral fertilizer over multiple seasons. We combine the simulated yields with socio-economic data from an agricultural household survey to calculate indicators of cropping-system performance. Our results show that a maize-groundnut rotation increases average economic profits by 75% compared with maize monoculture that uses more mineral fertilizer than in the rotation. The maize-groundnut rotation increases the stability of profits, reduces the likelihood of negative profits, and increases risk-adjusted profits. In contrast, the maize-groundnut rotation has a 54% lower average caloric yield and uses more labor than the maize monoculture with mineral fertilization. By comparing labor requirements with labor supply at the household scale, we show for the first time that the additional labor requirements of the maize-groundnut rotation can increase the likelihood of experiencing a labor shortage, if this rotation is undertaken by farm households in central Malawi. We demonstrate that risk and labor factors can be important when examining trade-offs among alternative cropping systems.

Performance of different cropping systems across precipitation gradient in North China Plain

Overuse of groundwater for irrigation under the current high yielding wheat-maize double cropping system has led to quick depletion of groundwater resources in North China Plain (NCP). Experimental work conducted for a relatively short period (several years) to explore water-saving cropping systems at limited sites offers useful, but limited insights regarding future sustainable cropping systems in NCP to balance productivity and groundwater usage. An understanding of the performance of various alternative cropping systems under the long-term inter-annual climate variability across the precipitation gradient in NCP is needed, but yet lacking. Our study provides a systematic assessment on productivity and environmental impact of 5 alternative cropping systems along a precipitation gradient across NCP, through combination of cropping systems modelling and scenario analysis. Our results show that the groundwater neutral cropping systems change from single summer maize, single spring maize, to wheat-maize double rotation from dry to wet areas across the precipitation gradient. Water restriction will inevitably lead to crop yield reduction (by 2–9 t/ha) and water saving depending on the choice of alternative cropping systems and location precipitation. Reduced water availability for irrigation will also reduce the amount of mineral nitrogen required and the associated N loss to the atmosphere and to the ground water. The reduction on N input was estimated to be 20–190 kg N/ha/year and N loss was 5–35 kg N/ha/year for the most productive cropping systems under rainfed conditions. A value for groundwater use is also estimated based on the extra grain yield produced with irrigation. The results provide the scientific basis for the design of future sustainable cropping systems, and future policies for water pricing and agricultural inputs (water and nitrogen).

Can a change in cropping patterns produce water savings and social gains: A case study from the Fergana Valley, Central Asia

Abstract The study examines possible water savings by replacing alfalfa with winter wheat in the Fergana Valley, located upstream of the Syrdarya River in Central Asia. Agricultural reforms since the 1990s have promoted this change in cropping patterns in the Central Asian states to enhance food security and social benefits. The water use of alfalfa, winter wheat/fallow, and winter wheat/green gram (double cropping) systems is compared for high-deficit, low-deficit, and full irrigation scenarios using hydrological modeling with the HYDRUS-1D software package. Modeling results indicate that replacing alfalfa with winter wheat in the Fergana Valley released significant water resources, mainly by reducing productive crop transpiration when abandoning alfalfa in favor of alternative cropping systems. However, the winter wheat/fallow cropping system caused high evaporation losses from fallow land after harvesting of winter wheat. Double cropping (i.e., the cultivation of green gram as a short duration summer crop after winter wheat harvesting) reduced evaporation losses, enhanced crop output and hence food security, while generating water savings that make more water available for other productive uses. Beyond water savings, this paper also discusses the economic and social gains that double cropping produces for the public within a broader developmental context.

Alternative Cropping Systems with Limited Irrigation

Alternative Cropping Systems with Limited Irrigation

Stable nutrient flows in sustainable and alternative cropping systems of globe artichoke

The conventional cultivation of globe artichoke causes high nitrogen (N) balance surpluses. The planning of more sustainable open-field horticultural systems (with no synthetic fertilizer supply) can contribute to the reduction of the nutrient surplus. We hypothesized that an artichoke conventional system could be shifted to a sustainable system through mineral fertilizer supply based on expected plant nutrient uptake, return of crop residues in well-defined growth phases, use of fertility-building crops, and crop rotations. Over a 10-year field experiment, three management systems, differing in fertilizer rates, crop sequence (monoculture/rotation with cauliflower), and legume cover crop adoption and management, were compared: (i) improved conventional, (ii) alternative monoculture, and (iii) biannual rotation. We monitored soil conditions at a sampling interval of approximately 3 years. We calculated gross N, P, and K balances for each growing season, and we also monitored soil respiration over the last two growing seasons. On average, the biannual rotation resulted in a well-balanced N budget (72 kg ha−1 N surplus) compared with improved conventional (160 kg N ha−1 N surplus) and alternative monoculture (− 34 kg ha−1 deficit) systems. By contrast, compared with the improved conventional system (133 and 116 kg ha−1 for P and K budgets, respectively), alternative monoculture and biannual rotation systems had negative budgets for P (− 9 kg ha−1 for both alternative systems) and K (− 58 and − 51 kg ha−1 for alternative monoculture and biannual rotation systems, respectively) in nine of ten growing seasons. Our results show for the first time that long-term biannual rotation with cauliflower coupled with cover crop use can optimize nutrient fluxes of conventionally grown globe artichoke. Overall, the study proposes a re-design of artichoke cropping systems, provides novel information useful for growers, and verifies that introducing a legume species cover crop is also the most promising approach to foster long-term sustainability.

Evaluating water conservation effects due to cropping system optimization on the Beijing-Tianjin-Hebei plain, China

Irrigation of the conventional double cropping system of winter wheat and summer maize has caused serious problems regarding water resources and the environment on the Beijing-Tianjin-Hebei plain (HP), China. Reducing or replacing high water consumption crops (such as winter wheat) is the most impactful way to effectively save water in the HP region. In this study, crop coefficient and vegetation remote sensing data were used to estimate evapotranspiration (ETa) for winter wheat and summer maize on the HP from 2009 to 2013. For early maize, ETa and yield were based on the results from the APSIM (Agricultural Production System Simulator) crop model, which had been calibrated and validated using field experimental data. The effects on groundwater conservation and grain yield were estimated at the regional scale for the conventional winter wheat (WW) and summer maize (SM) double cropping system (Y1M2) and three alternative cropping systems: three harvests in two years system (Y2M3, 1st year: WW-SM; 2nd year: early maize), four harvests in three years system (Y3M4, 1st year: WW-SM; the next two years: early maize), as well as a continuous early maize monoculture system (Y1M1). The results showed that: (1) Relative to Y1M2, the water savings in each alternative cropping system exceeded 50% of the groundwater overdraft on the HP. The evapotranspirations of Y2M3, Y3M4 and Y1M1 decreased by 14%, 19% and 29% over that of Y1M2 (740mm), respectively. The economic water use efficiencies (WUEe) of the alternative cropping systems were 7% –16% greater than that of Y1M2. The groundwater drop by Y1M2 (0.59myear−1) was higher than that by Y2M3 (0.20myear−1) and Y3M4 (0.07myear−1), and the drop by Y1M1 was negative, indicating a groundwater rise of 0.20m. The groundwater overdraft in Y1M2 was 160mm (3.83billionm3), and the alternative cropping systems were more sustainable, with groundwater overdrafts that were less than the recharge value of 128mm on the HP. (2) In comparison with Y1M2, the total yield was reduced by 2.28, 3.04 and 4.56billionkga−1 (or 7.7%, 10.2% and 15.3%) for Y2M3, Y3M4 and Y1M1, respectively, which accounted for <15% of the regional total or <1% of the national total. It is important to note that the yield loss of the alternative cropping systems was below the net grain export amount in Hebei province, so the grain supply and demand could be roughly balanced. (3) In summary, Y2M3 is a preferred alternative cropping system over Y1M2 in the near future because of the advantages of high WUEe, economic return, mitigated groundwater level decline and balance between wheat supply and demand on the HP. Y1M1, which had the least water use and highest WUEe and economic return, is an option for the most serious groundwater overdraft area despite a contradiction between the traditional dietary habit and complete abandonment of wheat. Y3M4 is recommended as the transitional cropping system between Y2M3 and Y1M1. The method in this study is applicable to relevant regional research, and the results can be of use to the government when formulating policies on cropping systems and groundwater management.

Evaluation of the Environmental Policy Integrated Climate (EPIC) Model on Predicting Crop Yield in the Canadian Prairies, a Case Study

The Environmental Policy Integrated Climate (EPIC) model was updated with relevant weather, tillage, and crop management operations from the 1994 to 2013 Alternative Cropping Systems study to asses...

Environmental impact assessment of different cropping systems of home-grown feed for milk production

Animal feeding is a critical point in terms of both production efficiency and environmental impact for the livestock sector and farmer choices about home-grown feed can have great influence on environmental impact of milk production. The aim of the study was to assess the environmental performances of the most common home-grown fodder crops in Northern Italy and to analyse the impacts of different cropping system scenarios for milk production, through a Life Cycle Assessment (LCA) approach. The environmental impact of the most common home-grown feeds was calculated from cradle-to-the-animal’s mouth expressing the different categories per hectare and per unit of net energy for lactation and protein digested in the small intestine when rumen-fermentable nitrogen is the limiting factor (PDIN). Moreover four scenarios (BASE, HAY, SILAGE, PROTEIN) characterized by different cropping systems were hypothesized to assess the environmental impact of milk production from cradle to farm gate in an intensive farming system. Primary data were collected by direct interviews in 134 dairy farms located in Lombardy Region (Northern Italy).Among the most common fodder crops grown in Northern Italy, alfalfa preserved as silage and, although with a lesser extent, the double cropping system “whole plant maize silage-Italian ryegrass hay” showed the best environmental performances especially when the impact are expressed per unit of net energy for lactation or digestible protein in the intestine. Alfalfa showed also the lowest values of acidification and eutrophication when they were expressed as unit of land. The high variability of forage quality suggests a great room for improvement in terms of mitigation potentials.The analysis of alternative cropping system scenarios for milk production showed that the cropping system based on alfalfa and grass hays (HAY scenario) had the lowest self-sufficiency in terms of DM and the highest values of all impact categories per kg of fat and protein corrected milk (FPCM). The PROTEIN scenario, characterized by the introduction in the cropping system of protein rich crops (whole plant soy silage and alfalfa hay) can be considered the best one in a global perspective. In fact, the PROTEIN scenario showed the lowest potentials for acidification, eutrophication and non-renewable fossil energy use per kg FPCM and a reasonable value in terms of GWP. Moreover, the PROTEIN scenario had the higher feed self-sufficiency in terms of both DM and CP. Thanks to their capability to fix atmospheric nitrogen increasing the cultivation of legume such as alfalfa and soy in the cropping system of Northern Italy can reduce the utilization of chemical nitrogen fertilization and, consequently, the environmental impact. Moreover, considering that the main part of soybean consumed in Italy is cultivated in South America, a higher farm self-sufficiency in terms of protein feeds could decrease the emissions of CO2 linked to land use change generated by the cultivation of soybean.