Fallow System Research Articles

Exploring a Moderate Fallow Scale of Cultivated Land in China from the Perspective of Food Security.

Food security remains a primary concern because of the large population and scarce land resources in China, and it is a core task to determine the appropriate proportion and scale of fallowing for fallow systems. The aim of this study was to systematically estimate the grain production potential (GPP) of existing and unexcavated cultivated land due to land use change from 1990 to 2017 and calculate the theoretical fallowing scale by using a population carrying capacity model. The reserved GPP from cultivated land to be excavated was 7470 × 104 t in China, and the GPP stored by the change in grain yield per unit, multiple crop index (MCI) decline, and agricultural structure adjustment were 921 × 104 t, 4321 × 104 t, and 7760 × 104 t, respectively, and the lost GPP caused by construction land expansion was 5287 × 104 t. The population carrying capacity of cultivated land in China was estimated to be 1.469 to 1.515 billion in 2017 on the basis of the national average living standard. The proportion of the population that could be fed more was between 6.28% and 9.54% depending on the number of people included, which provided an opportunity to implement the fallowing system in China. Meanwhile the proportions of the theoretical fallow scale were 6.28% and 9.54%, and the fallow scale ranged from 850 × 104 hm2 to 1296 × 104 hm2 under the premise of fully tapping the potential of cultivated land. In addition, taking the decline in MCI as an example, the grain yield reduction was equivalent to the grain yield of 829 × 104 hm2 of newly reclaimed cultivated land over the past 30 years, which saved 621.48 billion yuan. The costs and benefits when formulating relevant policies of land utilization should be considered, and exploiting the productive capacity of cultivated land that exists is better than reclaiming new cultivated land.

English

In tropics, species diversity in agricultural systems is often assessed without distinction between native and exotic species. However, the conservation value of an ecosystem depends on its richness in native species. This study was conducted to determine the conservation value of agricultural systems in Togo megahotspot, one of the species-rich sites in Upper Guinean. Specifically, the study compares fallow systems (FS), coffee systems (COFS), cocoa systems (COCS) to forest relics (FR) on the one hand, and on the other hand the agricultural systems (FS, COFS, COCS) between them base on natives tree species diversity and composition. Sites have been selected to represent different forest lands use types. Plots (n = 233) of different sizes (400, 500 and 625 m²) were used for data collection. In each plot, all living trees (DBH ≥ 10 cm) were counted. Rarefaction, generalized linear models (GLM) and ecological distance approach were used to standardized and compare the data. A total of 183 species were recorded, of which 42% were absent from the agricultural plots. Difference in diversity index were significant between the FR and agricultural systems (p<0.001), but not between agricultural systems (p=0.23). Guineo-Congolian climax and endemic species were seriously under threat. The study poses a real problem of regeneration dynamic of these species in human-dominated landscapes that requires further specific work.   Key words: Rainforests, agricultural practices, biodiversity conservation, Reducing Emissions from Deforestation and Forest Degradation (REDD+), Togo, Upper Guinean.

Management of High-Residue Cover Crops in a Conservation Tillage Organic Vegetable On-Farm Setting

A three year on-farm conservation-tillage experiment was initiated in fall of 2008 at Randle Farm LLC, located in Auburn, AL. Our objective was to evaluate and demonstrate implementation of tenable conservation vegetable production practices using high amounts of cover crop residues that reduce soil erosion, improve soil productivity and quality, reduce energy costs, and promote farm profitability. Cereal rye, crimson clover, and a rye and crimson clover mixture were evaluated as cover crops; these were terminated using either a prototype two-stage roller/crimper alone or followed by an application of 2.5 L a.i. ha−1 45% cinnamon (Cinnamomum verum L.) oil (cinnamaldehyde, eugenol, eugenol acetate,)/45% clove oil (eugenol, acetyl eugenol, caryophyllene) mixture in the spring prior to crop establishment. A winter fallow conventional tillage system was included for comparison. Watermelons, cantaloupes, and okra then were transplanted into each cover crop and termination treatment combination in mid-May, utilizing a modified transplanter equipped with a custom fitted subsoiling shank and row cleaners to alleviate soil compaction and facilitate transplanting. In all years, all cover crop treatments exceeded 4000 kg ha−1and in 2009 and 2011, exceeded 6000 kg ha−1. At 21 days after termination in 2010 when the slowest termination occurred, higher termination rates were obtained for cereal rye (95% to 96%) followed by lower termination rates for the clover/rye mixture (83% to 85%); the lowest termination rates were obtained for crimson clover (66% to 68%). Commercially available cinnamon/clove oil solution provided little cover crop termination above that provided by a roller crimper alone. Volumetric soil moisture content for rolled/crimped cover crops was consistently higher compared to the conventional system, indicating that flattened and desiccated cover crop residue provided water conservation. In 2010 and 2011, yields for cantaloupe, okra, and watermelons were consistently higher for the conventional system compared with no-till system with cover crops likely due to weed cultivation limitations and insect pressure. Future studies need to focus on weed control and integrated pest management.

Soil chemical and biological fertility, microbial community structure and dynamics in successive and fallow sugarcane planting systems

ABSTRACTSugarcane yields are declining under successive planting (monoculture) compared to other planting systems in Florida Histosols. To evaluate soil properties related to the sugarcane yield decline, an on-farm study was conducted on soil chemical, biological, and microbial indicators variation with soil samples collected from successive green cane or burnt cane harvest, flooded fallow, and rice and sweetcorn rotation planting sites. Overall, harvest residue incorporated in the soil in green cane harvest and corn rotation increased organic matter, total carbon and C:N ratios which resulted in higher microbial biomass parameters and total PLFA biomass. However, successive planting with burnt cane harvest reduced total soil carbon and hence microbial biomass. Findings suggested that these parameters should be considered for further research to determine specific causes of sugarcane yield decline in successive planting.

Responses of weed community, soil nutrients, and microbes to different weed management practices in a fallow field in Northern China.

The long-term use of herbicides to remove weeds in fallow croplands can impair soil biodiversity, affect the quality of agricultural products, and threaten human health. Consequently, the identification of methods that can effectively limit the weed seed bank and maintain fallow soil fertility without causing soil pollution for the next planting is a critical task. In this study, four weeding treatments were established based on different degrees of disturbance to the topsoil: natural fallow (N), physical clearance (C), deep tillage (D), and sprayed herbicide (H). The changes in the soil weed seed banks, soil nutrients, and soil microbial biomass were carefully investigated. During the fallow period, the C treatment decreased the annual and biennial weed seed bank by 34% against pretreatment, whereas the H treatment did not effectively reduce the weed seed bank. The D treatment had positive effects on the soil fertility, increasing the available nitrogen 108% over that found in the N soil. In addition, a pre-winter deep tillage interfered with the rhizome propagation of perennial weeds. The total biomass of soil bacterial, fungal, and actinomycete in H treatment was the lowest among the four treatments. The biomass of arbuscular mycorrhizal fungi in the N treatment was respectively 42%, 35%, and 91%, higher than that in the C, D, and H treatments. An ecological weeding strategy was proposed based on our findings, which called for exhausting seed banks, blocking seed transmission, and taking advantage of natural opportunities to prevent weed growth for fallow lands. This study could provide a theoretical basis for weed management in fallow fields and organic farming systems.

Improving soil aggregation, aggregate‐associated C and N, and enzyme activities by green manure crops in the Loess Plateau of China

AbstractGreen manure and fertilization practices have substantial impacts on soil chemical and biological properties over time. A field experiment was conducted on Cumulic Haplustoll to investigate the effects of leguminous green manure (LGM) crops and nitrogen (N) fertilizer on dry‐stable soil aggregate distributions and stability, the concentrations of organic carbon (OC) and N in the bulk soil and separated aggregate fractions, and soil enzyme activities in dry croplands on the Loess Plateau of China. Species tested as LGM crops were Huai bean (Glycine ussuriensis Regel et Maack.), soybean (G. max (L.) Merr.) and mung bean (Phaseolus radiatus L.). Two rates of N fertilizer (0 and 162 kg N ha−1) applied to winter wheat sown after LGM was incorporated into surface soil. Results showed that the inclusion of LGM crops for 6 years significantly increased the total nitrogen (TN), soil organic carbon (SOC), aggregate‐associated N and OC concentrations, enhanced the values of aggregate content with >0.25 mm size (R0.25) and mean weight diameter (MWD), and boosted soil enzyme (invertase, urease, dehydrogenase and aryl‐sulfatase) activities at the 0–20‐cm depth compared to the bare fallow system under dryland conditions. The long‐term application of N fertilizer substantially increased the proportion of macroaggregates (>5.0 mm), MWD and N contents in the 0.25–5‐mm size aggregates, and promoted the relative activities of invertase, alkaline phosphatase, dehydrogenase and aryl‐sulphatase, but decreased the urease activity. The correlations among macroaggregate fractions and soil chemical properties, aggregate stability and enzyme activities were significant and positive; however, the correlations between small aggregate fractions (<2 mm) and corresponding parameters were negative, or there were no correlations. Overall, combining green manuring practices with suitable N fertilizer application should be recommended to improve the soil quality in dryland regions similar to the Loess Plateau of China.Highlights Green manure crops significantly increased soil enzyme activities, SOC and total N contents. Green manure crops increased macroaggregate (>5 mm) formation and stability. Application of N fertilizer significantly increased the proportions and stability of macroaggregates. Green manure crops along with N fertilizer helped to build better soil quality in a dry loess cropland.

Efficacy of Cover Crops on Weed Suppression, Wheat Yield, and Water Conservation in Winter Wheat–Sorghum–Fallow

ABSTRACTReducing the fallow period by using cover crops in a winter wheat (Triticum aestivum L.)–sorghum [Sorghum bicolor (L.) Moench]–fallow system has the potential to suppress weeds and improve wheat yield, yet limited information is available from the semiarid southern Great Plains (SGP) of the United States. This study determines the effects of spring‐planted cover crops on weed suppression and winter wheat yields in semiarid environments. The study used a randomized complete block design with eight cover crop treatments and three replications. The cover crop treatments consisted of fallow (weeds controlled with herbicide), pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea + oat, pea + canola, pea + oat + canola, and six‐species mixture of pea + oat + canola + hairy vetch (Vicia villosa L.) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.). Both winter wheat and cover crops received supplemental irrigation. The cover crops showed potential to suppress weeds and maintain good ground cover during summer. Specifically, weed biomass in the oat and oat mixtures with legumes and brassicas were 73 to 85% less than in fallow during 2018. Cover crops showed little effect on wheat yield, yield components, and water use efficiency. Although long‐term studies of cover crops effects on multiple ecosystem services may help to select the most effective cover crop on wheat yield and water use efficiency in the SGP, this study revealed benefit of cover cropping through weed suppression.

Soil Microbial and Chemical Properties of a Minimum and Conventionally Tilled Wheat–Fallow System

Tillage alters the soil environment and microbial communities responsible for decomposition and nutrient cycling. This study aimed to evaluate the effects of tillage intensity (minimum vs. conventional) on the soil chemical and microbial properties of a winter wheat (Triticum aestivum L.)–fallow rotation in the low‐precipitation zone of the Pacific Northwest. Soils collected for 2 yr at two depths from both crop phases (wheat and fallow) were analyzed for pH, nutrient availability, total C and N, fungal and bacterial gene abundance, and enzyme activity related to C, P, and N cycling. All soil variables excluding soil pH were significantly greater in the top 10 cm of the soil. Except for pH and nitrate, all were greater in 2016 than in 2017. Across the full rotation, tillage did not affect any measured parameter. Instead, crop phase influenced several soil chemical properties and arylamidase activity, although the effects were not consistent across depth. Fungal abundance was influenced by tillage intensity but only in the top depth under wheat, indicating a phase‐specific effect rather than a change persisting across the entire rotation. Soil enzymes were strongly related to total C, total N, and phosphate across the two soil depths, but effects were inconsistent between depths and across phases. Overall, crop phase and year were stronger drivers of soil chemical and microbial properties than tillage intensity. Short‐term (<4 yr) tillage intensification does not have a strong influence on the nutrient cycling capacity of soil, although fungal numbers may decline in the cropped phase.Core Ideas Tillage intensification did not induce strong changes in soil properties. Sample year and depth were significant factors impacting soil chemistry and biology. Wheat‐cropped soil had more fungal DNA under minimum than conventional tillage. Impacts of tillage were minor and limited to comparisons within each crop phase.

Soil Health Response of Cover Crops in Winter Wheat–Fallow System

Core Ideas Effect of cover crops on selected soil health indicators and wheat yield was monitored.Response of soil organic matter pools varied with cover crops and sampling dates.Oat and its mixtures as cover crops have potential to improve soil health. Cover cropping has a potential to improve soil health in semiarid regions. This research evaluated the effects of spring‐planted cover crops on selected soil health indicators in limited‐irrigated winter wheat (Triticum aestivum L.)–fallow system. Soil health parameters measured include soil water content (SWC), soil organic carbon (SOC), soil total nitrogen (STN), potentially mineralizable carbon (PMC), potentially mineralizable nitrogen (PMN), permanganate oxidizable carbon (POXC), inorganic N, and available P. Cover crops tested were pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea + oat (PO), pea + canola (PC), pea + oat + canola (POC), pea + oat + canola + hairy vetch (Vicia villosa L.) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.) (SSM), and a fallow. Cover crops were planted in February and terminated in May after 85 to 90 d. Cover crop biomass was 33 to 142% greater with oat, PO, PC, POC, and SSM than pea and canola. The SWC was 2 to 3% lower under cover crops than fallow plots at their termination, but was 2 and 4% greater in SSM and POC than fallow at wheat planting in October. Soil inorganic N was 41 to 49% lower with cover crops than fallow at termination date. Soil PMC and POXC varied with cover crop species and sampling dates. The SOC and STN contents were 18 to 20% greater with oat than PC. Oat and its mixture with other cover crops show promises to improve soil health and resilience.

Impact of planted hedgerow fallows on nutrient balances in a groundnut/maize/cassava intercrop

ABSTRACTTo assess if the nutrient supply through planted tree fallows meets crop nutrient uptake and export, N, P, K, Ca and Mg uptake and export by a groundnut/maize/cassava intercrop was compared with the nutrient uptake by three planted fallow systems (Senna spectabilis, Flemingia macrophylla, Dactyladenia barteri) and a no-tree control. Three cycles of two years fallow and one year cropping on Ultisol in southern Cameroon were studied. Fallows were slashed and burned. The fallow system had no consistent effect on nutrient uptake by individual crops. Crop nutrient uptake was most often highest in the S. spectabilis system. Nitrogen balances were generally negative due to N loss in the burn. Across three cropping cycles, the balance of fallow nutrient uptake versus total crop nutrient uptake was only in the S. spectabilis system positive for all nutrients. Nutrient export by all crops (mean of three years) was unaffected by fallow systems. The fallow nutrient uptake versus crop nutrient export balance was positive for all nutrients and systems. Planted fallows appear capable of acquiring sufficient nutrient stocks during fallow phases, covering the crops’ demand. Fallow N and K uptake and crop export declined with every fallow/cropping cycle.

Crop and varietal diversification for enhancing productivity and profitability of rice fallow system in eastern Himalayan region

Rice fallow is predominant system in eastern Himalaya, a reason for low agricultural productivity in the region. In north eastern regions of India, farmers grow rice crop during rainy season (June to November) and keep the land fallow after rice harvest in the post-rainy season (November to May) due to inadequate irrigation water availability and insufficient rainfall. There was an urgent need to develop location specific crop diversification plan suitable to existing conditions with appropriate crops and their varieties. Crop diversification is also required to mitigate the effect of climate change. Moisture conservation practices like zero tillage and residue retention as mulch reduce carryover time between two crops and ensure moisture availability in the soils for low water requiring crops. Therefore, attempts were made to develop suitable crop diversification options under rice fallow areas with promising cultivars of oilseed and pulse crops. A field experiment was conducted to assess productivity, profitability and soil health of rice fallow land under diversified sequential cropping pattern. The results reveal that inclusion of pea, lentil and rapeseed with minimum tillage and mulching under rice fallow system recorded highest net return (` 71.28 × 103, ` 72.65 ×103 and ` 29.26 × 103, respectively). Seed productivity enhancement was 47.5, 61.7 in rapeseed, 31.0, 52.1 in pea and 39.0, 56.0 in lentil under minimum tillage, and minimum tillage with mulching over farmers' practice. Improved management practices (minimum tillage and mulching) also recorded remarkable net return of 69.3, 66.6 and 84.8% over farmers existing practices in rapeseed, pea and lentil crops, respectively. The soil fertility status after harvest of the crops improved in the agro-technique with minimum tillage and mulching.

Carbon Stock as Related to Fallow Age in the Sudano-Guinea Savannahs of Ngaoundere, Adamawa, Cameroon

Aim/Objectives: In order to assess the fallow contribution on the carbon cycle and soil organic matter restoration, a study of the carbon dynamics was undertaken in fallow systems of 1, 2, 5 and 20 years old in the Ngaoundere savannahs of Cameroon.
 Methodology: Carbon stock was estimated in 100 m2 plot for shrubs, in 1 m2 plot for understorey, litter and earthworm casts, and 0.0625m2 plot for fine roots and soil. The experimental design was randomised complete block with three replicates. The age of fallows was the mean treatment whereas the plots were the replicates.
 Results: The results showed that the phytomass increased with fallow age, except that of shrubs. Soils and earthworm casts were the mean carbon sinks in the four fallows, with more than 55.61% and 26.24% of the total carbon stock respectively in the soil and earthworm casts. The total carbon stock increased with fallow age, from 34.54 in the young fallows to 154.52 tC.ha-1 in the old fallows. In the same way, vegetation and soil carbon increased with fallow age except that of shrub. The results showed that the carbon stock was influenced by floristic composition and spatial distribution of the vegetation, which related to fallow age.
 Conclusion: These preliminary results will contribute to the understanding of the impact of fallow age on the global carbon cycle and awareness in the conservation of fallows for the environment protection.

A conceptual framework to study soil aggregate dynamics

The objective of this study was to develop a conceptual framework to study soil aggregate dynamics through the integration of aggregation, disruption, stabilization and destabilization processes of soil constituent units. We used aggregate‐size distribution and water stability of macroaggregates to evaluate changes in soil aggregates in two ecosystems where one is the ‘reference’ state and the other is the ‘new’ state. The framework was validated with data from (a) a non‐buffered annual row crop (ARC) system, (b) a no‐till (NT) system and (c) a bare fallow (BF) system. The dynamics of soil aggregates in the ARC were dominated by the disruption of aggregates (the aggregation–disruption index (ADI) was −0.08), in NT they were dominated by the aggregation process (ADI = 0.03) and in BF dominated by the disruption of aggregates (ADI = −0.20). Three pathways were observed: (a) expression of the aggregation process, which is essential in reestablishing soil structure and functionality, (b) expression of the disruption process, which is critical in the destruction of soil structure and (c) prevalence of mixed behaviour, where the dominant process depended on the relative rate of aggregation and disruption. The proposed framework and study of the carbon associated with aggregates could pave the way for the development of a methodology for the quantitative study of soil organic carbon (SOC) dynamics, carbon inputs (outputs), soil carbon fractions, and edaphic and biotic conditions that regulate SOC dynamics.Highlights Soil aggregate dynamics were assessed within multiple management systems. A new methodology is proposed for the quantitative study of soil aggregate dynamics. Provided an understanding of aggregation, disruption, stabilization and destabilization in aggregate dynamics. Aggregate dynamic pathways of value in land management can minimize deterioration of the environment.

Lentil enhances the productivity and stability of oilseed-cereal cropping systems across different environments

Abstract Enhancing the stability of crop production is vital for agriculture under climate uncertainty. Conventional fallow and shallow-rooting pulse crops such as lentil (Lens culinaris Medic.) have been incorporated in oilseed-cereal cropping systems to cope with dry conditions on the semiarid Canadian prairies. However, the static and dynamic stability of these adaptation practices at a cropping system level is unclear due to the complexity of interactions. This study assessed the effects of diversified rotation systems as drought adaptation practices on the productivity and stability of oilseed-cereal cropping systems. Nine 3-year crop rotations were tested for two cycles at three sites from 2013 to 2016. The 3-year crop sequences included fallow, lentil, and spring wheat (Triticum aestivum L.) in rotation phase 1, followed by canola (Brassica napus L.), oriental mustard (Brassica juncea L.), and camelina (Camelina sativa L. Crantz) in phase 2, and the rotation phase 3 was durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.) in all nine rotation systems. On average, the lentil system increased system productivity, expressed by annualized durum wheat equivalent yield, by 24% and 78% compared with the spring wheat and fallow systems, respectively. Stability analysis revealed that the lentil – B. juncea – durum wheat and lentil – B. napus – durum wheat systems had the least variation across the environments and were well adapted to high-yielding sites. The fully-phased rotations across various environments showed that the drought-induced reductions in system productivity ranged from 3 to 47% compared with yields under normal weather, with the lentil – oilseed – durum systems having least reduction. Quantitative assessments revealed that about 36% of the variation in system productivity was associated with rotation systems and additional 30% was due to weather-related factors. In conclusion, the inclusion of lentil in rotation increases systems productivity and reduces yield variation in oilseed-cereal cropping systems in changing environments.

Constructive-technological diagram of the rotary–string cultivator and the definition of its main parameters

Organizing technological processes in accordance with adopted system of agriculture, producers of agricultural products tend to get maximum possible yield with minimizing costs and increasing the level of soil fertility. A fallow system is one of effective systems of soil processing for accumulation of nutrients and moisture, as well as weed control. Fallow cultivation of soil is used when using this system for weed control. First cultivation is carried out with help of fallow or continuous cultivators, which have low productivity and high energy intensity. To eliminate these shortcomings, authors proposed a structural and technological scheme of a rotor-lug cultivator, the main element of which is rotor-string working bodies on flexible shaft. Tillage rotary-string work by hauling leads to propelling-rotational effects. There were obtained analytical dependences for determining speed of string required for cutting stem of weeds under different physical-mechanical parameters of stem and soil, as well as technological indicators of a cultivator’ operation. The authors obtained expressions for determining the radius of string installation from axis of rotation, angle of section installation to the direction of motion of energy means, as well as the number of strings required for guaranteed cutting of weeds deeper than the point of growth.

Long-term fertiliser (organic and inorganic) input effects on soil microbiological characteristics in hydromorphic paddy soils in China

This study investigated long-term fertilisation effects on soil microbiological characteristics of hydromorphic paddy soils. The study was conducted in 30-year-old experimental plots with various treatments involving chemical fertiliser (nitrogen, phosphorus, and potassium) alone or in combination with manure in relation to a control in a rice–rice–fallow system at the farm at Jiangxi Academy of Agricultural Science. The soil microbial biomass carbon (SMBC) and nitrogen (SMBN), microbial enzyme activity, and microbial community structure were analysed. Changes in levels of SMBC and SMBN in response to combinations of organic–inorganic fertilisers were significantly higher than for inorganic fertiliser treatment. Furthermore, activities of microbial enzymes (sucrase, urease, proteinase, acid phosphatase, and catalase) were significantly higher in combined than in inorganic fertiliser and control treatments. Additionally, the richness and evenness of soil bacteria were decreased by long-term fertilisation, especially inorganic, whereas the Shannon–Weiner and richness indexes of soil fungi were higher. Long-term fertilisation with high doses of combined organic–inorganic input significantly increased microbial biomass, enzyme activity, and fungal community diversity. However, the same input decreased bacterial community diversity. This study will be useful for improving fertilisation management in hydromorphic paddy soils.

Short-Term Benefits of Grain Legume Fallow Systems on Soil Fertility and Farmers Livelihood in the Humid Forest Zone of Cameroon

Short-Term Benefits of Grain Legume Fallow Systems on Soil Fertility and Farmers Livelihood in the Humid Forest Zone of Cameroon

Applying the Values and Practical Implementation of Agricultural Science in Nigeria farming System

No one can underrate the many significant contributions and potentials for Agriculture in the totality of the Nigerian economy. The key to developing agriculture in Nigeria is studying, researching and identify means to efficiently support the small-scale farming practiced by a majority of the populace. The paper is not advocating the abandonment of the medium and large-scale farming levels, but the small and scattered agriculture prevalently practiced has evinced the needs to empower more this category through receiving more support from aid donors and the governments. Therefore, identifying ways to encourage this level of farming is vital, though presently middle and large-scale agriculture is receiving more emphasis, which does not correspond to any visible increase of the gross national products. Also, for the fact that the above 75 percent of the population that engages in agriculture that gets up to about 95 in some urban and rural areas during the rainy season are mostly small-scale farmers. These, are the lots of the small farmers that cultivate about 90% of the 83 million hectares developed of the 98 million hectares of the arable land area. As per Nigeria, small-scale farming accounts for about 95% of total agricultural output - Federal Ministry of Agriculture, 2005 [1]. For the fact that agrarian science is such a broad multidisciplinary field, the goal to pursue is self-sufficiency in food production to enhance the lives of the masses by improving the capacity of the small-scale farmers who efficiently produce almost the food consumed through the innovative applications of some parts of the discipline of agricultural science. Notably, by applying Soil Science, and Production techniques like irrigation management, recommended nitrogen inputs, thereby improving the agricultural productivity, optimally dissemination of information and free urban/rural farming vocation skills pieces of training. Also, shall invariably enhance productivity and remove from the farmers the stress of always relying on seasonal rainfall and from the catastrophe to the ecosystem caused by the bush fallow system, especially in the Niger Delta region because of the high rate of gas flaring. Mainly this time that the UNEP in Ogoniland (topsoil) cleanup operations that are going on to improve the environment and grow healthier efficient crops for consumption.

Disentangling how management affects biomass stock and productivity of tropical secondary forests fallows

A better understanding of biomass production in secondary forests after cultivation is essential for assessing the resilience of slash and burn systems and their capacity to deliver ecosystem services. Biomass production is influenced by management legacies, landscape configuration and soil, but these drivers are rarely studied simultaneously, nor is the role of changes in vegetation properties in linking them to biomass production. We assessed how management legacies affect biomass in secondary forests created by slash and burn in the central Congo Basin, and tested whether changes in productivity could be attributed to changes in stem density, functional diversity, functional identity or soil. Using data from 6452 trees in 96 fallow plots nested in 3 study sites, we looked for the main determinants of aboveground biomass (AGB) of woody vegetation in fallow systems. Next, using a subset of 58 plots in fallow fields aged 5 to 10 years, we used confirmatory path analysis to explore the relations between management history, soil, vegetation properties and biomass productivity. The sampled fallow fields had, on average, 58.4 (±46.2) Mg ha−1 AGB. AGB was positively related to both fallow age and to the proportion of remnant trees in AGB and negatively related to the number of previous cultivation cycles. Biomass productivity varied with the number of previous slash-and-burn cycles, with notable declines in the fourth cycle. The effect of management history was mainly through a reduction in the dominance of fast growing tree species and in the number of regenerating stems, which were also indirectly affected by an increase in C. odorata cover. Soil fertility status and the biomass of remnant trees also modified biomass productivity. Our findings suggest that under the current management intensity the capacity of the slash and burn system to provide important ecosystem functions, such as carbon sequestration, is declining.

Effects of the Chinese arable land fallow system and land-use change on agricultural production and on the economy

This study focuses on economic effects of arable land fallow system and land-use change in China using a dynamic single-country, multi-regional computable general equilibrium model. Land supply is adjusted endogenously in our model. Land use in each of 31 provinces is tracked by a land-use change module, which is calibrated with satellite data. Our results reveal that the expansion of real output can be attributed to the increase in capital stock as a result of the growth of investment due to the imposition of the arable land fallow system in China. And the growth of investment is caused by the release of labor from agriculture The reduced supply of arable land in agricultural land contraction regions is partially offset by the increasing arable land in agricultural land expansion regions. Rural households benefit more than urban households from the arable land fallow policy due to relatively higher income and lower rural CPI.