Effects Of Cropping Systems Research Articles

The Effect of Organic vs. Conventional Cropping Systems on the Yield and Chemical Composition of Three Courgette Cultivars

Courgette is a popular vegetable belonging to the Cucurbitaceae family. It is known for its good adaptation to different weather conditions, although it performs best in a warm and humid climate. Since the yield and various quality characteristics of vegetables are known to be strongly influenced by a number of weather, agronomic, and genetic (variety/cultivar) factors, in this study we aimed to compare three cultivars of courgette (Atena, Lajkonik and Soraya) grown in two consecutive growing seasons in the organic and conventional agronomic systems. The concentrations of nitrates, nitrites, carotenoids (lutein, zeaxanthin, β-carotene) and chlorophylls (chlorophyll a, chlorophyll b) in courgette fruits were analyzed by HPLC. The growing season had a predominant effect on the yield as well as the majority of the analyzed compositional parameters of the courgette fruits. The studied cultivars differed significantly in the concentration of lutein, β-carotene, and chlorophylls, although some significant interactions between the cultivar and the growing season were observed. On average, organically grown courgettes were characterized by a significantly higher yield, as well as higher dry matter and chlorophyll content, however, this agronomic system’s effect was not consistent among all the studied cultivars in the two seasons. The study suggests that organic practices have a potential to provide high yields of good quality crops, comparable (or, in the case of some parameters, better) than the conventional, resource-intensive horticulture.

Effect of Cropping System under Tillage and Mulching on Soil Physical Properties and Water Use Efficiency by Maize (Zea mays L.) in Southern Benin

In agriculture, water has become a limiting factor because of the effects of climate change felt by farmers. This situation seriously compromises agricultural production through pockets of drought, delayed and early cessation of rains and then an increase in the length of the dry season.
 Aims: This study aims to evaluate the effect of tillage and vegetative mulch on soil physical properties and maize water use efficiency in ferralitic soil of southern Benin.
 Study Design: The Factorial Complete Randomized Block Design with 4 repetitions was implemented.
 Place and Duration of Study: The experimental site is located at Allada, in southern Benin, and conducted between May 2017 and July 2017.
 Methodology: Tillage (No-tillage, flat tillage) and straw mulch rate (0%, 50%, 75% soil cover) and their interaction was been tested during this study. The physical properties of soil and maize water use efficiency were determined.
 Results: Tillage significantly reduced soil temperature by 2.65% and improved soil permeability by 60%. Tillage also significantly improved water use efficiency for maize grain from 3.88 to 7.88 kg.mm-1.ha-1 and for maize biomass from 12.67to 23.31 kg.mm-1.ha-1. Mulching significantly improved soil moisture from 11.54% to 13.13%, water use efficiency for maize grain from 4.26 to 7.58kg.mm-1.ha-1 and for maize biomass from 14.50 to 22.05 kg.mm-1.ha-1. Mulching also significantly reduced soil temperature by 11%. The combination of tillage and mulching significantly improved water use efficiency for maize grain and biomass production. The highest water use efficiency (8.87 kg.mm-1.ha-1 for maize grain and 25.17 kg.mm-1.ha-1 for maize biomass) was achieved with tillage combined with mulching at 75% soil cover. The interaction between these two factors significantly reduced soil temperature by 11.30% (tillage combined with mulch at 75% soil cover) compared to control (no-tillage and no-mulch).
 Conclusion: This study showed that tillage and mulching at 50% or 75% soil cover improves soil physical properties and water use efficiency for maize production in the context of climate change.

Effects of different long-term cropping systems on phoD-harboring bacterial community in red soils

Phosphorus (P) is the main factor limiting crop production in red soils. Examining the bacterial community harboring phoD gene under different long-term cropping systems may supply meaningful insights for improving soil P availability. Here, we analyzed how the cropping systems affect community structure of phoD-harboring bacteria by changing physicochemical properties in red soils. Twenty-four soil samples from eight cropping systems (abandoned farmland, corn continuous cropping, mango continuous cropping, taro continuous cropping, zucchini–corn rotation, pea–corn rotation, canola–tobacco rotation, and walnut–tobacco intercropping for > 10 years) were collected from 0 to 20 cm depth in Miyi County, Sichuan Province, China. The abundance of phoD gene was determined by quantitative PCR, and phoD-harboring bacterial community structure was analyzed by high-throughput sequencing. Available P concentration and phoD abundance were the highest in pea-corn rotation soil, while alkaline phosphatase (ALP) activity was the lowest in this soil. Available P showed a significant positive relationship with phoD abundance, while a negative relationship with ALP activity. Moreover, the dominant phyla of phoD-harboring bacterial community were Proteobacteria and Actinobacteria, with Cupriavidus and Bradyrhizobium being the dominant genera. The relative abundances of Streptomyces, Pseudomonas, and Amycolatopsis were positively related to soil P concentration (total and available P) and negatively related to ALP activity, indicating that these genera may be essential in the mineralization of soil organic P. Redundancy analysis (RDA) showed that ALP, soil organic carbon (SOC), and N:P ratio were the remarkable factors affecting the structure of phoD-containing bacterial community across all cropping system soils. Meanwhile, structural equation model (SEM) showed that the effects of total N and available P on soil phoD-harboring bacterial community structure were stronger than that of SOC. Further, soil texture was also one of the main factors affecting the phoD-harboring bacterial community structure, which had a notable up-regulation effect on abundance and diversity of phoD gene and indirectly regulate gene composition by affecting available P. The long-term cropping systems can affect the community structure of phoD-containing bacteria and ALP activity by altering physicochemical properties, and thus contribute to regulation of the biogeochemical cycle of P in red soils. The main factors driving the changes in phoD-harboring bacterial community structure were soil texture, SOC, total N, and available P.

Assessment of Diazotrophic Proteobacteria in Sugarcane Rhizosphere When Intercropped With Legumes (Peanut and Soybean) in the Field.

Several factors influenced the sugarcane production, and among them, higher use of nitrogen and depletion of soil nutrient constitutes a significant concern in China. Sugarcane-legume intercropping may help to regulate the microbial structure and functions. In the present study, sugarcane rhizosphere soils of three cropping systems: Sugarcane only (S-only), sugarcane with peanut (S + P), and sugarcane + soybean (S + S) were sampled in tillering, elongation, and maturation stages from two different experimental fields. High-throughput sequencing technologies applied to assess the effects of different cropping systems on the structure of nitrogenase (nifH) gene communities. A total of 3818 OTUs (operational taxonomic units) were acquired from all soil samples. Intercropping systems noticeably increased the relative abundance of Proteobacteria in the tillering stage. The increased microbial diversity in the rhizosphere was mainly due to soil organic carbon and total soil N. In contrast, intercropping has no significant negative impact on microbial abundance, but sugarcane growth stages influence it significantly, and two bacteria (Bradyrhizobium and Pseudacidovorax) showed significant shift during plant growth. The results provide insight into the microbial structure of Proteobacteria in the sugarcane legume-intercropping field, and how microbial community behaves in different growth stages. It can boost the microbial activity of the soil, and that could be a new strategy to stimulate soil fertility without causing any negative impact on crop production.

Production potential and economics of mustard under different cropping sequences with reference to integrated nutrient management

The experiment was conducted during Rabi season of 1999-2000 and 2000-01 on sandy loam soil at JNKVV, College of Agriculture, Farm, Gwalior (M.P.) to study the effect of different cropping systems and fertility levels on yield, yield attributes and economics of mustard (var. Pusa bold). Results showed that the maximum seed yield (23.05 q ha -1 ), oil content (40.39%), net return (Rs. 23661 ha -1 ), energy output (74024 MJ ha -1 ) and B:C ratio (3.19) were observed in blackgram – mustard followed by Peral milletmustard cropping system. Fertilizer application of 50% RD + Azotobacter + PSB @ 20g kg -1 seed, resulted in maximum net return (Rs. 20797 ha -1 ) and B.C. ratio (2.99) as compared to higher application of fertilizers.

Establishing reference values for soil microbial biomass-C in agroecosystems in the Atlantic Forest Biome in Southern Brazil

Abstract Soil microbial biomass plays a key role in the biogeochemical cycles, degradation of organic pollutants and soil aggregation, and its estimation through soil microbial biomass-C (MB-C) is often referred as a potential indicator of soil functioning. This study aimed to identify reference values of MB-C that would relate to crop yield. Soybean and maize grain yields and microbial biomass-C (MB-C) data were gathered from studies listed in “Web of Science” performed in agroecosystems located in the Atlantic Forest Biome in Southern Brazil. Database was composed by 78 datasets, where soil samplings for evaluation of MB-C were performed at the 0–10 cm layer at flowering stage, and evaluated by the fumigation-extraction method. A meta-regression using the Mitscherlich model was applied to determine the MB-C reference value corresponding to 80% of maximum yield. The effects of soil management systems and crop systems were verified by comparing the confidence intervals. Soil tillage decreased MB-C and yield, while crop rotation increased yield but not MB-C. It was not possible to find a reference value for soybean, because of the variability not explainable by the MB-C. The reference value related to high maize yield (>6,752 kg ha−1) was of 170 μg C g−1 soil, but further results must be included to decrease the variability.

Effect of Cropping System and Humidity Level on Nitrate Content and Tipburn Incidence in Endive

Tipburn is an important disorder caused by a calcium deficiency that affects the marketability of endives. Genotype, air relative humidity, and temperature are directly involved in tipburn occurrence. Our study aimed to investigate the effect of cropping systems and relative humidity on the marketable yield, nitrate accumulation, and incidence of tipburn in endives. Two cultivars were evaluated in pots (‘Cuartana’ and ‘Natacha’), two cropping systems (greenhouse and open-field), and in two different air humidity levels (high level: plants under a plastic tunnel with an extra supply of humidity with micro-sprinklers, and low level: plants without an extra supply of humidity and outside of a plastic tunnel) during two years (2013 and 2014) in different growing seasons. Nitrate content was determined by reflectometry, and tipburn was evaluated using a qualitative scale. Results showed that tipburn was favored under greenhouse with low humidity levels, with 40–60% plants affected. ‘Natacha’ was more susceptible to tipburn (>20% plants affected) than ‘Cuartana’ (<20% plants affected). Leaf nitrate accumulation was favored by the highest temperatures (greenhouse). It is concluded that in our conditions, tipburn incidence in endives depends on the interaction of genotype and the environmental conditions. Nitrate content was more influenced by the temperature than by the cultivars used.

Highly diversified crop systems can promote the dispersal and foraging activity of the generalist predator Harmonia axyridis

High plant biodiversity and landscape food provision stability is known to have a positive impact on biocontrol services provided by natural enemies. However, few studies have assessed how differential spatial and temporal crop richness actually impact biocontrol services, and notably how natural enemies may spill-over among crops. Within this framework, using a four-cage maze system under laboratory conditions, we evaluated the effect of a diversified crop system (four crops, namely cotton, tomato, squash and soybean) and low diversified crop systems (one single crop), on the generalist predator Harmonia axyridis (Pallas) and its predation capacity on aphids. The system varied food availability both in space, i.e. different cages, and in time, i.e. different dates of resources implementation. In general, the effects of crops on the natural enemies’ traits observed in the diversified crop system resulted from the average effects of the individual low diversified crop systems; the impact of the predator was highly dependent on the plant. Low diversified crop systems actually proved to be either very suitable for the predator’s development (tomato and squash), or not at all (soybean and cotton), but inversely suitable in reducing pest population with lower efficacy in tomato and squash and higher efficacy in soybean and cotton. The spillover of the ladybird was strongest in the squash low diversified crop system and lowest in the cotton one, other systems showing intermediate spillover values. In the diversified crop system, the ladybird presence was always closely related to plant presence, and aphid populations were maintained at a stable population increase. Still, the predator was also found in cages lacking plants, as opposed to the low diversified crop systems; this hinted at the potential of the highly diversified crop system to promote ladybird dispersal and increase foraging activity. We demonstrate that increasing crop diversity in agroecosystems may help promote biocontrol services provided by H. axyridis by promoting its spillover between crops (e.g. while the plants are senescing and/or when they are harvested).

Effect of Cropping System and Nitrogen on Maize and Soy Bean Yields in Western Kenya

Inherent low soil fertility in the highly weathered and degraded soils largely accounts for low and unsustainable crop yields in most African countries (Okalebo et al., 2006; Sanchez et. al., 1997). Productivity of maize and soybeans in Kenya, particularly in the western region is generally low. The high costs of inorganic fertilizers and the possibility of decreasing soil productivity in due to soil mining and environmental pollution demands a reassement of their use, vis-a-vis, other alternative technologies. The objective of this study was to assess the effect of selected cropping systems, N fertilizer and manure on maize and soy bean crop yields in western Kenya (Bungoma, Vihiga, and Teso). The experiment was a split plot design arranged and laid down in a randomized complete block design (RCBD) with three replications. Cropping systems (mono cropping, MBILI and conventional) were the main factor while fertility interventions (FYM and CAN) were the treatments. The cropping systems consisted of conventional (Maize and soy beans were planted as intercrop in 37.5 cm alternating rows), MBILI (Managing Beneficial Interactions in Legume Intercrops), maize and soybean monocrop. Five fertilizer treatments were used: calcium ammonium nitrate and farm yard manure, both applied at the rate of 30 kg N ha-1 and 75 kg N ha-1, respectively, and absolute control that had no added treatment. Field experiments were planted during two cropping seasons of short rains season (August to December 2011) and one long rains season (April to August 2012) Generally, maize yields were found to be significantly higher in both the mono cropping system (mean yield: 2.00 t/ha) and MBILI system (mean yield: 1.77 t/ha) compared to conventional farming (mean yield: 1.27 t/ha). Soybean yields were found, overall, to be significantly higher in the mono cropping system (mean: 1.00t/ha) compared to both MBILI (mean: 0.75 t ha-1) and conventional system (mean: 0.59 t ha-1). For both maize and soy bean grain, application of CAN75N and planting with FYM75N were found to significantly increase yields, compared to either top dressing with CAN30N or planting with FYM30N. CAN generally produced higher yields with monocrop system whereas MBILI system did better when FYM is used, suggesting that an optimal system could consist of MBILI with organic fertilizers. The mean Land Equivalent Ratio (LER) values were always greater than 1.0 for intercropping and I.0 for mono cropping system. Manure was found to produce similar yields as those in fertilizer applications. This study recommends MBILI system and organic manure as a beneficial way of growing maize and soy beans

Soil functions are affected by transition from conventional to organic mulch-based cropping system

Soil ecosystem services depend on soil properties and their interactions, which are mostly influenced by soil use and management. The main objective of the present study was to evaluate, through a multidisciplinary approach, the effect of different cropping systems on food provisioning, soil chemical features, size and structure of soil microbial community, soil invertebrate biodiversity and habitat provision (trophic interactions). The systems were: conventional integrated (INT); traditional organic with cover crops and conventional tillage (ORG); and organic coupled with conservation agriculture (cover crop mulching and no-tillage, ORG+). During 2016, we conducted soil and field samplings and collected data relative to the crop yield, C and N content in the agroecosystem, chemical and microbial soil properties and soil invertebrate abundance and trophic interactions. The INT system showed the highest crop yield (similar to ORG and three-fold higher than ORG+). Nevertheless, the INT system showed the greatest amount of N lost with drainage water (six-fold higher than the other systems), the lowest soil total PLFA abundance (around two-fold lower than ORG and ORG+ in the Ap1 horizon of soil). Additionally, INT system was characterized by the lowest invertebrate biodiversity (e.g., two-fold and ten-fold lower than ORG and ORG+ respectively for ground-dwelling predator abundance). By contrast, the ORG+ system had the lowest crop yield, but it showed the highest soil total organic C concentration and microbial biomass in the Ap1 horizon, supported higher invertebrate biodiversity and a slightly wider prey-spectrum for ground beetle predators. The ORG system had an intermediate behaviour between INT and ORG+. The results of this study demonstrate that, despite the reduction of crop yield, the conversion from INT to ORG or ORG+ possibly enhances important soil functions like nutrient cycling and storage, biodiversity and habitat provisioning. However, management optimization for improving crop yield would be required to make ORG+ a viable system.

Effect of conservation tillage and rice-based cropping systems on soil aggregation characteristics and carbon dynamics in Eastern Indo-Gangetic Plain

Traditional rice–wheat cropping system, which follows wet puddling in rice and conventional tillage in wheat, is deteriorating soil health resulting yield stagnation in the Indo-Gangetic Plains of South Asia. Conservation agriculture which endorses minimum soil disturbance, residue retention and crop diversification not only improves soil health but also reduces the CO2 concentration in atmosphere. We hypothesized that adoption of conservation agriculture could improve the soil health and soil organic carbon in comparison with conventional practices. A field experiment was conducted during 2012–2015 to observe the effects of different tillage practices and cropping systems on soil aggregation and carbon dynamics. The experiment comprised of three cropping systems, viz. rice–wheat, RW; rice–maize, RM; rice–lentil, RL, practiced in three tillage practices, viz. conventional tillage, CT; reduced tillage, RT; reduced tillage with 30% residue, RT30 in factorial randomized block design. Adoption of RT and RT30 resulted in higher macroaggregate content of 51.7 and 61.2%, respectively, in comparison with CT. Total water stable aggregates and mean weight diameter (MWD) of aggregates were considerably higher in RT and RT30 treatments, and the effect was most pronounced in the upper 0–15 cm soil layer. The rice–maize cropping system registered the highest macroaggregate content, water stable aggregates (WSA) and MWD of 55.6%, 80.0% and 2.28 mm, respectively, in the upper surface soil. The rice–maize cropping systems under RT30 recorded the highest total soil organic carbon (SOC) stock (51.0 Mg ha−1) in comparison with other systems after 3 years of experimentation. Reduced tillage and residue management resulted in positive changes in soil infiltration rate. The effect of tillage operations and cropping systems on different soil properties (aggregate distribution, WSA, MWD and geometric mean diameter of aggregates, SOC stock, Bulk density) was mostly limited to surface layer of soil.

Long-term effect of rice-based cropping systems on pools of soil organic carbon in farmer's field in hilly agroecosystem of Manipur, India.

A comprehensive study on various pools of soil organic carbon (SOC) under different rice-based cropping systems is necessary for predicting their effect on soil quality through carbon build-up in soil and their impact on global climate change. The present investigation was undertaken to study the long-term effect of six different rice-based cropping systems (continuously followed by farmers > 10years) on various SOC pools viz., total organic carbon (TOC), oxidizable organic carbon (Coc) and its different fractions [Cfrac1 (very labile), Cfrac2 (labile), Cfrac3 (less labile) and Cfrac4 (non-labile)], soil microbial biomass carbon (SMBC) and lability index (LI) and SOC stock at the farmer's field of Kakching district under hilly ecosystems of Manipur, India. In every cropping system, all the fractions of Coc were significantly decreased with increasing soil depth. Among all the fractions, Cfrac4 (non-labile) constituted the largest percentage of TOC for both surface (0-20cm) and sub-surface (20-40cm) soil varying from 47.95-58.45% and 55.76-64.83% with average values of 51.87 and 59.73% respectively. Results also revealed that the Cfrac1 (very labile) of Coc constituted highest (42.79%) percentage of Coc and that of Cfract4 constituted highest percentage (55.80%) of TOC. In both soil depths, rice-pea cropping system recorded highest TOC, Coc and SMBC followed by rice-French bean and rice-potato. In surface soil, the lowest TOC, Coc and SMBC were recorded in rice-mustard which was statistically at par with rice-cabbage. The SOC stock of both soil layers was also recorded highest in rice-pea. The highest LI of surface soil was recorded in rice-potato which was statistically equal with rice-pea and rice-French bean. Significant correlations among different pools/fractions of C and with available nutrients indicate their importance in improving soil quality. Long-term combination of rice with the leguminous crops and/or potato enhanced Coc, TOC, SMBC, LI and active pools (Cfrac1 + Cfrac2) of rapid turnover rate that may influence the quality and productivity of soil. Long-term cultivation of rice-French bean with high passive C along with good active C and LI is proved to be a good cropping system for sustaining soil and environment by enhancing quality and C reserve of degraded soils of hilly agroecosystem.

Effects of corn-based cropping systems on phosphorus fractions and availability in red soil

To clarify the effects of corn-based cropping systems on phosphorus (P) fractions and availability in red soil, we measured P fractions and availability of topsoil (0-20 cm) and subsoil (20-40 cm) in abandoned farmland (control) and three corn-based cropping systems (corn continuous cropping, zucchini-corn rotation and pea-corn rotation), respectively. The results showed that total P, available P contents and P activation coefficient in topsoil were higher than those in subsoil. The value of relative P parameters in topsoil of pea-corn rotation was the highest among all cropping systems. Organic P was the main P fraction in red soil, accounting for 57.8%-81.1% (topsoil) and 74.3%-85.5% (subsoil) of total P. Except for pea-corn rotation soil, sodium hydroxide extractable P (NaOH-P) was the main P fraction in other cropping systems. The contents of water-soluble P (H2O-P) and sodium bicarbonate extractable P (NaHCO3-P) with high availability were lower than other P fractions, only accounting for 0.3%-2.1% (topsoil) and 1.7%-10.0% (subsoil) of total P. The pea-corn rotation soil had the highest hydrochloric acid extractable P (HCl-P) content in topsoil and subsoil, and significantly differed from other cropping systems. The contents of available P, sodium bicarbonate extractable organic P (NaHCO3-Po), sodium hydroxide extractable organic P (NaOH-Po) and hydrochloric acid extractable inorganic P (HCl-Pi) were significantly correlated with pH, cation exchange capacity, iron-aluminum oxides and soil texture. In conclusion, pea-corn rotation was the most suitable system to improve P availability of red soil in Panxi area.

Organic Cropping System Affects Grain Chemical Composition, Rheological and Agronomic Performance of Durum Wheat

Durum wheat plays a central role for Italy, a country characterized by an historical tradition of pasta making. This crop is one of the major sources of starch in the Mediterranean diet, also providing substantial amounts of nutrients, either essential or healthy, such as minerals and phytochemicals. In this study, the effect of cropping system (organic (ORG) and conventional (CONV)) on the content of proteins, wet gluten, minerals, and total polyphenols (TPC), as well as on the antioxidant activity (AA) and yield characteristics were evaluated in nine genotypes of whole durum wheat. The analysis of variance confirmed the key role of cropping system, which explained more than 50% of the total variation for some minerals (Na, K, and Fe), and more than 80% for proteins, wet gluten, and TPC. The CONV reported the highest levels of proteins, wet gluten, and ash, whereas the TPC and AA were statistically higher in the ORG ones. The quality traits under study were also genotype dependent. For instance, ‘Ramirez’ had a higher ash content under ORG than CONV, while ‘Core’ had an opposite behavior. This study provides a better understanding about the effect of both cropping system (ORG vs. CONV) and genotype on the yield and qualitative traits of the whole grain durum wheat.

Midwestern cropping system effects on drainage water quality and crop yields.

Grain producers are challenged to maximize crop production while utilizing nutrients efficiently and minimizing negative impacts on water quality. There is a particular concern about nutrient export to the Gulf of Mexico via loss from subsurface drainage systems. The objective of this study was to investigate the effects of crop rotation, tillage, crop residue removal, swine manure applications, and cereal rye (Secale cereale L.) cover crops on nitrate-N (NO3 -N) and total reactive phosphorus (TRP) loss via subsurface drainage. The study was evaluated from 2008 through 2015 using 36 0.4-ha plots outfitted with a subsurface drainage water quality monitoring system. Results showed that when swine manure was applied before both corn (Zea mays L.) and soybean [Glycine max (L.) Merr.], drainage water had significantly higher 8-yr-average flow-weighted NO3 -N concentrations compared with swine manure applied before corn only in a corn-soybean rotation. The lowest NO3 -N loss was 15.2kg N ha-1 yr-1 from a no-till corn-soybean treatment with rye cover crop and spring application of urea-ammonium nitrate (UAN) to corn. The highest NO3 -N loss was 29.5kg N ha-1 yr-1 from swine manure applied to both corn and soybean. A rye cover crop reduced NO3 -N loss, whereas tillage and residue management had little impact on NO3 -N loss. Losses of TRP averaged<32g P ha-1 yr-1 from all treatments. Corn yield was negatively affected by both no-till management and cereal rye cover crops. Results showed that cropping management affected N leaching but impacts on P leaching were minimal.

Effect of Cropping System and Rice Residue Retention on Crop Productivity and Soil Physical Properties in Rice Based Cropping System of Bangladesh

Cropping systems of Bangladesh are highly diverse and cultivation costs of puddled transplanted rice (PTR) are high. Therefore, an improved system is needed to address the issues, a field experiment was conducted during 2011-2013 to evaluate system intensification with varying degrees of cropping systems and residue retention. Four cropping systems (CSE) namely CSE1: T. boro rice-T. aman rice (control), CSE2: wheat-mungbean-T. aman rice (wheat and mungbean sown using a power tiller-operated seeder (PTOS) with full tillage in a single pass; puddled transplanted aman), CSE3: wheat-mungbean-dry seeded DS aman rice (DSR), and CSE4: wheat-mungbean-DS aman rice (all sown by PTOS with strip tillage) were compared. Two levels of aman rice residue retention (removed; partial retention i.e. 40 cm of standing stubble) were compared in sub plots. Grain yield was significantly higher (by 11%) when wheat was grown after DSR than PTR. Similarly, PTR and DSR (aman rice) produced statistically similar crop yields. Rice residue retention resulted a significantly higher (by 10%) wheat yield and a slightly increased (by 6%) mungbean yield than that of residues removed. The system productivity of CSE4 was significantly higher (by 10%) than CSE1 when averaged of the two years data. Partial aman residue retention gave significantly higher system yield than residue removal (by 0.6 t ha-1). After two years, no effect of CSE or partial aman residue retention was found on soil physical property (bulk density) of the top soil. Therefore, CSE4 along with residue retention would be more effective for sustainable crop production.&#x0D; The Agriculturists 2019; 17(1-2) 14-30

Effect of Long-Term Cropping Systems on the Diversity of the Soil Bacterial Communities

Soil microbial communities are involved in the maintenance of productivity and health of agricultural systems; therefore an adequate understanding of soil biodiversity plays a key role in ensuring sustainable use of soil. In the present study, we evaluated the influence of different cropping systems on the biodiversity of the soil bacterial communities, based on a 54-year field experiment established in Martonvásár, Hungary. Terminal restriction fragment length polymorphism (T-RFLP) fingerprinting technique was used to assess soil bacterial diversity and community structure in maize monoculture and three different crop rotations (maize–alfalfa, maize–wheat and the maize–barley–peas–wheat Norfolk type). No differences in richness and diversity were detected between maize monoculture and crop rotations except for the most intense rotation system (Norfolk-type). Although the principal component analysis did not reveal a clear separation between maize monoculture and the other rotation systems, the pairwise tests of analysis of similarity (ANOSIM) revealed that there are significant differences in the composition of bacterial communities between the maize monoculture and maize–alfalfa rotation as well as between wheat–maize and Norfolk-type rotation.

Effects of different long-term cropping systems on phosphorus adsorption and desorption characteristics in red soils

Phosphorus (P) fertilizer has been applied in regions with red soils to ensure high crop yield. However, the supply of bioavailable P for crop plants is insufficient due to the strong adsorption and fixing behaviors in red soils. In this study, we explored P adsorption and desorption characteristics in red soils under different long-term cropping systems. We also analyzed how the cropping systems affect P adsorption and desorption through changing soil physicochemical properties under the experimental conditions. Eighteen red soil samples were collected at depths of 0–20 cm from six cropping systems (abandoned farmland, corn continuous cropping, taro continuous cropping, pea–corn rotation, canola–tobacco rotation, and walnut–tobacco intercropping for at least 10 years) in Miyi County, Sichuan Province, China. Soil physicochemical properties, zeta potentials, and P adsorption and desorption characteristics were evaluated. The P adsorption capacity of soils increased at a decreasing rate with increasing exogenous P concentration, while the P desorption capacity increased constantly; however, the change in the percentage of desorbed P had no clear trend. The soils under pea–corn rotation and taro continuous cropping had lower P adsorption capacities and higher P desorption capacities compared to those under the other cropping systems. The maximum P adsorption capacities (Qm) of pea–corn rotation and taro continuous cropping soils were 16.1% and 32.4% of abandoned farmland soil, while the corresponding desorption coefficients were 6.93 and 1.62 times higher than that of abandoned farmland soil, respectively. Soil available P (AP), cation exchange capacity (CEC), and clay content were positively correlated with a and readily desorbable P (RDP), while they were negatively correlated with Qm (P < 0.05); opposite trends were found in the sand content. In addition, the zeta potential of soil colloids decreased with increasing soil pH. Among the cropping systems, the absolute value of zeta potential was lowest for tobacco–walnut intercropping, while its isoelectric point was the highest, resulting in the highest P adsorption capacity. The long-term cropping systems affect P adsorption and desorption characteristics and P availability in red soils by influencing soil physicochemical properties. The main factors driving the changes in P adsorption behavior were AP, CEC, free Fe oxides, and sand content, while AP, sand, and clay contents were the major factors for the P desorption.

Forage and maize yields in mixed crop-livestock farming systems: Enhancing forage and maize yields in mixed crop-livestock systems under conservation agriculture in sub-humid Zimbabwe

In mixed crop-livestock farming systems, smallholder farmers face the challenge of insufficient dry season livestock feed whilst crop production is mainly constrained by poor soil fertility and erratic rains. Conservation agriculture (CA) which is premised on three main principles namely minimal soil disturbance, crop rotations and mulching is being promoted as a potential solution to declining soil productivity. However, farmers implementing CA in mixed crop-livestock systems are conflicted by the use of crop residues either as livestock feed or as mulch under crop production. A study was carried from 2012/13 to 2014/15 season in Murehwa, a sub-humid region of Zimbabwe, to evaluate the effects of maize-legume cropping systems on forage, maize grain yield and gross margins. In this context, forage refers to the plant material/biomass harvested for livestock feeding. The cropping systems involved one conventional tillage practice with continuous sole maize (CT), four CA treatments consisting of continuous sole maize, maize-mucuna intercrop, maize-cowpea intercrop and maize-groundnut/soybean rotations. The experiment was replicated on eight farmers’ fields with each farmer treated as a replicate. Maize-mucuna (4 134 kg ha-1) and maize-cowpea (3 999 kg ha-1) intercrop systems significantly increased forage yield compared to CA sole maize (3 646 kg ha-1) and CT sole maize (3 076 kg ha-1). Among the rotations, maize-soybean rotation system performed better than the maize-groundnut system with respect to forage yield and maize grain. Intercropping and sole cropping systems however showed no significant maize grain yield difference. The highest and lowest gross margins/ha were obtained from the maize-mucuna intercrop (US$1395) and maize-soybean rotation system (US$507), respectively. The study thus suggests that farmers can grow legumes as intercrops with maize without any loss in maize grain yield. Maize-mucuna intercropping was the best of the tested cropping systems with respect to forage yield and gross margins in mixed crop-livestock systems of Murehwa.

Long-term effects of agricultural production systems on structure and function of the soil microbial community

Microbes are central drivers of soil processes and in-depth knowledge on how agricultural management practices effects the soil microbiome is essential in the development of sustainable food production systems. Our objective was therefore to explore the long-term effects of organic and conventional cropping systems on soil bacterial and fungal quantity, their community structures and their combined function. To do so, we sampled soil from a long-term experiment in Southeast Norway in 2014, 25 years after the experiment was established, and performed a range of microbial analyses on the samples. The experiment consists of six cropping systems with differences in crop rotations, soil tillage, and with nutrient application regimes covering inorganic fertilizers, cattle slurry (both separately and combined with inorganic fertilizers) and biogas residues from digested household biowaste. The quantity of soil microbes was assessed by extraction of microbial C and N and by analysis of soil DNA (bacterial 16S rRNA, and fungal rRNA internal transcribed spacer region). The structures of the microbial communities were determined and assessment of relatedness of bacterial and fungal communities was done by the unweighted pair group method. Estimates of richness and diversity were based on numbers of unique operational taxonomic units from DNA sequencing and the function of the microbial assembly was measured by means of enzyme assays. Our results showed that production systems including leys had higher microbial biomass and higher numbers of bacterial and fungal gene copies than did systems with cash crops only. A cropping system which appeared to be particularly unfavourable was a reference-system where stubble, roots and exudates were the single source of organic material. Production system significantly affected both bacterial and fungal community structures in the soil. Systems including leys and organic fertilization had higher enzyme activities than did systems with cash crops only. An inclusion of ley in the rotation did not, however, increase either microbial richness or microbial diversity. In fact, the otherwise suboptimal reference-system appeared to have a richness and diversity of both bacteria and fungi at levels similar to those of the other cropping systems, indicating that the microbial function is largely maintained under less favourable agricultural treatments because of the general resilience of soil microorganisms to various stresses. Neither disturbance through tillage nor the use of chemical fertilizer or chemical plant protection measures seemed as such to influence soil microbial communities. Thus, no differences between conventional and organic farming practices as such were found. We conclude that the choice of agricultural management determines the actual microbial community structure, but that biodiversity in general is almost unaffected by cropping system over many years. Adequate addition of organic material is essential to ensure a properly functioning microbial ensemble and, thus, to secure soil structure and fertility over time.