Grass Intercropping Research Articles

Soybean in Crop Rotation with Maize and Palisade Grass Intercropping Enhances the Long-term Effects of Surface Liming in No-till System

Tropical and subtropical soils are characterized by low natural fertility. Therefore, further research needs to be undertaken to increase surface liming efficiency, improve soil quality, and promote crop development. The low solubility of lime has hampered acidity correction in deeper layers, particularly if a no-tillage system is used. However, surface liming efficiency can be improved if efficient crop rotation programs are implemented. Therefore, the main aim of this study was to investigate the long-term effects of lime doses on soil fertility and the cascading effects of these changes in soybean nutrition and productivity after maize monocrop or intercropped with palisade grass during three growing seasons. In a long-term experiment (started in 2019), soybean was cultivated under four lime doses (0, 2000, 4000, and 6000 kg ha−1) applied to soil surface in two crop systems (after maize monocrop or intercropped maize with palisade grass) during three consecutive agricultural years (2016–2019). Liming reduced soil acidic parameters and increased P, Ca2+, Mg2+, and S–SO42− availability down the soil profile, which improved soybean nutrition and grain yield, particularly when it followed intercropped maize. Intercropping exploits species complementarities, which results in increasing the effectiveness of surface liming under no-tillage systems, contributing to higher soybean yields in crop rotation.

Characteristics of light energy utilization of intercropping alfalfa/gramineae forage based on yield effect

Based on field experiments in 2017-2019, we examined the characteristics, yield effect and regulatory mechanism of light energy utilization in alfalfa/gramineous forage grass intercropping. With monoculture of alfalfa, forage triticale (C3 plant), and forage maize (C4 plant) as control, we measured the yield effect, the effect of light energy utilization factor on yield formation, the characteristic difference and mechanism of light energy utilization under alfalfa/triticale and alfalfa/maize intercropping patterns. Results showed that land equivalent ratios of both intercropping patterns were all greater than 1, indicating that land utilization ratio and yield benefit of the two intercropping patterns were higher than that of monoculture, among which alfalfa/triticale intercropping pattern was the most promising one. The contribution of light energy utilization factors to yield was following an order of leaf area index (1.531) > net photosynthetic rate (0.882) > intercellular CO2 concentration (0.282) > transpiration rate (-0.229) > canopy opening (-0.291) > PAR interception rate (-0.681) > stomatal conductance (-0.751). Among them, leaf area index was not only one of the important indices to characterize photosynthetic capacity, but also an important component factor of forage crop yield aiming at harvesting nutrients. Therefore, among all factors of photosynthetic characteristics, net photosynthetic rate was the main factor affecting yield. The net photosynthetic rate of alfalfa, triticale and maize under intercropping showed the same pattern, and being different from that of monoculture. The main ways for intercropping to increase net photosynthetic rate included: triticale and maize increased net photosynthetic rate and yield by enhancing the carboxylation fixation capacity of CO2 and the utilization capacity of strong light, while alfalfa could improve its net photosynthetic rate and promote growth under low light, by increasing the content of chlorophyll b in functional leaves, changing chlorophyll composition and enhancing the collection and transmission of light energy.

Decision analysis of agroforestry options reveals adoption risks for resource-poor farmers

Agroforestry interventions have the potential to benefit the livelihoods of farmers and communities worldwide. However, given the high system complexity, the long-term benefits of agroforestry are difficult to anticipate. This study aimed to integrate uncertainty into long-term performance projections for agroforestry interventions in the highlands of Northwest Vietnam. We applied decision analysis and probabilistic modeling approaches to produce economic ex-ante assessments for seven agroforestry options (intercropping of maize, forage grass, or coffee with tea, nut, fruit, and timber trees) promoted in the region. Our results indicate that farmers likely prefer annual monocultures due to the relatively early incomes and short time-lag on returns. However, the results also show that annual profits from monocrops can be expected to decrease over time, due mainly to unsustainable soil use. Agroforestry systems, on the other hand, return substantial profits in the long term, but they also incur high establishment and maintenance costs and can generate net losses in the first few years. Initial financial incentives to compensate for these losses may help in promoting agroforestry adoption in the region. Uncertainties related to farmers’ time preference, crop yields, and crop prices appeared to have the greatest influence on whether monocropping or agroforestry emerged as the preferable option. Narrowing these key knowledge gaps may offer additional clarity on farmers’ optimal course of action and provide guidance for agencies promoting agroforestry interventions in Vietnam and elsewhere. Our model produced a set of plausible ranges for net present values and highlighted critical variables, more clarity on which would support decision-making under uncertainty. Our innovative research approach proved effective in providing forecasts of uncertain outcomes and can be useful for informing similar development interventions in other contexts.

Evaluation and Tradeoff Analysis of Ecosystem Service for Typical Land-Use Patterns in the Karst Region of Southwest China

Although many land-use patterns have been established to restore vegetation and eliminate poverty in the karst area in southwest China, the ecosystem services (ESs) of these patterns are still not fully understood. To compare the differences in seven typical monoculture patterns and three agroforestry patterns, their ESs and tradeoffs were analyzed within the Millennium Ecosystem Assessment Framework. Compared with the local traditional corn pattern, the marigold pattern improved provisioning, regulating, and cultural services by >100%. The pomegranate pattern provided far more provisioning services than the other patterns. The apple + soybean intercropping pattern reduced regulating services, and eventually, its Total ESs (TES) and ecosystem multifunctionality index (EMF) also decreased. Cultural services will be enhanced by the introduction of fruit trees, as well as intercropping. Orange + peach had the greatest negative tradeoffs between provisioning and regulating services (P-R), provisioning and supporting services (P-S), and provisioning and cultural services (P-C), which indicates that the provisioning services urgently require improvement. Peach + pumpkin intercropping decreased the negative tradeoffs of P-R, P-S, and P-C (all > 10%), while pomegranate + grass intercropping increased the negative tradeoffs of R-S and R-C (all > 100%). Our results suggest that all six of these patterns are worthy of promotion but the pomegranate pattern should be given priority. Among the three intercropping patterns studied herein, the apple + soybean pattern should be redesigned to improve performance.

Alternative sugarcane production for conservation of sandy soils: sugarcane straw, intercropping and nitrogen

ABSTRACT The expansion of sugarcane cultivation in the Center-South region of Brazil has led to the use of, mainly, areas with low-yielding sandy soils. In this context, the objectives of this study were to evaluate the maintenance of the sugarcane straw, Brachiaria grass intercropping in sugarcane fields and nitrogen fertilization and on sandy soils in the state of Paraná. The field experiment was installed in the Paranavaí-PR city, at a unit of the Interuniversity Network for the Development of the Sugarcane Sector (RIDESA). The soil was classified as Latossolo Vermelho-amarelo distrófico. The treatments in the plant cane stage, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha-1) and monoculture or Brachiaria grass intercropping in sugarcane fields were arranged in a 4x2 factorial design. At plant cane harvest, the effect of unremoved straw was included as a new factor to be evaluated in the ratoon crops. The treatments in the ratoon crops were arranged in a 4x2x2 factorial design, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha-1), monoculture or Brachiaria grass intercropping in sugarcane fields and the presence or removal sugarcane straw. The sugarcane straw on soil surface can increase the agronomic development of sugarcane and, the other hands, Brachiaria grass intercropping in sugarcane fields can reduce. Sugarcane was responsive to N rates and, in the highest rates, compensated the sugarcane straw absence and reduced Brachiaria grass intercropping competition.

Interspecific interactions contribute to higher forage yield and are affected by phosphorus application in a fully-mixed perennial legume and grass intercropping system

Although intercropping is a common technique that has been widely applied, the effect of phosphorus (P) fertilization on productivity of a fully-mixed perennial intercropping system composed of four species, including two legumes and two grasses, has rarely been studied. The objective of this study was to determine the effect of interspecific interactions on forage yield and the influence of P application on interspecific competitiveness and yield in a fully-mixed intercropping system of alfalfa (Medicago sativa L.), sainfoin (Onobrychis viciifolia Scop.), orchardgrass (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb.). A three-year (2016–2018) field experiment was conducted in central China with an annual rainfall and temperature of 456 mm and 9.5 ℃, respectively. Five legume and grass seeding ratios (L: G) of 5:5, 4:6, 3:7, 6:4, and 7:3 were included, with four monocultures used as the control. The total forage yield was measured when 20% of the alfalfa flowers had opened (BBCH 62). Competitiveness indices, including the land equivalent ratio (LER), aggressivity (A), relative crowding coefficient (K values), competitive ratio (CR), and actual yield loss (AYL), were assessed. The total forage yield increased under fully-mixed intercropping in 2017–2018 when a transgressive overyielding advantage was attained, which was contributed by the interspecific interactions and P application. Moreover, the maximum yield and highest intercropping advantage appeared in L: G 3:7 and L: G 5:5 under 80 kg ha−1 P application in 2017–2018. Additionally, adequate P (80 kg ha−1) contributed to higher A values, K values, CR, and AYL of alfalfa and orchardgrass than in sainfoin and tall fescue, which suggested greater interspecific benefits and land-use efficiency. The fully-mixed intercropping system of alfalfa, sainfoin, orchardgrass, and tall fescue realized these potential advantages by coordinating interspecific interactions and environmental resources, which were manipulated by P application.

Impacts of the nitrogen application on productivity and nutrients concentrations of the corn-Congo grass intercropping system in the dry season

ABSTRACT The corn-grass intercropping system began to be used in the dry season, as it provides increased straw production for the no-tillage system. However, corn and grass are plants demanding in nitrogen. The corn cultivated in the dry season is called out-of-season corn in Brazil. The objective of this study was to evaluate the productivity and nutrients concentrations of out-of-season corn and Congo-grass intercropped in the no-tillage system, as a function of the nitrogen rates applied in sidedressing. The treatments were four nitrogen rates, 0, 30, 60 and 90 kg ha−1. The experimental design was randomised complete blocks with four replicates. The experimental period corresponded to the harvests of 2015 and 2016. There were evaluated: corn grain yield, dry mass production and nutrient concentration in the shoots of the plants intercropped. The evaluations were carried out at the physiological maturity stage of the corn and at the time of desiccation of the grass. Nitrogen increased grain yield and dry mass production of the plants intercropped. Nitrogen maximised the magnesium concentration in out-of-season corn and the nitrogen, calcium, magnesium and sulphur concentrations in Congo grass. Excess nitrogen promoted reduction of the phosphorus in the Corn-Congo grass intercropping system in the dry season.

Productive and nutritional characteristics of Brachiaria brizantha cultivars intercropped with Stylosanthes cv. Campo Grande in different forage systems

Pastures are the most practical and cost-effective way to feed cattle and are the basis of livestock production in Central Brazil. Grass–legume intercropping is essential for increasing production in sustainable animal-feeding systems. The aim of the present study was to evaluate the productive and nutritional characteristics of Brachiaria brizantha (A.Rich.) Stapf (palisade grass) cultivars intercropped with Stylosanthes cv. Campo Grande (multiline 80% S. capitata and 20% S. macrocephala) in different forage systems, in different seasons of the year, over a 2-year period. A randomised block experimental design was used, with three replicates. The treatments consisted of the following seven forage systems: Piata palisade grass, Paiaguas palisade grass, Stylosanthes cv. Campo Grande, row intercropping of Piata palisade grass and Stylosanthes, mixed intercropping of Piata palisade grass and Stylosanthes, row intercropping of Paiaguas palisade grass and Stylosanthes, and mixed intercropping of Paiaguas palisade grass and Stylosanthes. Evaluations were performed in each season of the year (winter, spring, summer, autumn) on the same plots over the 2-year period. Piata and Paiaguas palisade grass behaved similarly in all forage systems, indicating that both can be intercropped with Stylosanthes. Grass–legume intercropping had a positive effect on the productive and nutritional characteristics of the forage plants, increasing dry matter production, crude protein concentrations and in vitro dry matter digestibility, and decreasing the fibre fractions. Row intercropping was more efficient at maintaining high proportions of legume plants in the system, resulting in greater forage production and quality.

Intercrops improve the drought resistance of young rubber trees

The expansion of rubber cultivation into drought prone areas calls for innovative management to increase the drought resistance of the trees. The competition for water exerted by an intercrop in the upper soil layers will likely stimulate the growth of young rubber tree roots into deeper soil layers where water availability is more stable. This study examined the effects of a legume (Pueraria phaseoloides) and a grass (Vetiveria zizanoides) intercrop, on the fine root traits of young rubber trees (Hevea brasiliensis Mull. Arg.) established along a toposequence covering a range of soil depths in northeast Thailand. Two plots with and without the intercrops were set up in a 3-year-old rubber plantation. Tree girth, mortality rate, nutrient content in the leaves, predawn leaf water potential, and soil water content profiles were monitored over four successive years. Fine root length density, specific root length, fine root biomass, and fine root diameter of the rubber trees were measured in the fourth year. In shallow soils, the trees with the legume intercrop had a higher growth rate, a higher leaf nutrient content, and a higher fine root length density in the deepest soil layers than the controls, supporting the hypothesis of an adaptive root response, increasing drought resistance. However, the trees with the grass intercrop did not show this effect. In deep soils, specific root length was highest without the intercrops, and the soil water profile and predawn leaf water potential suggested that trees with intercrops benefited from increased water extraction below 110 cm depth. We showed, for the first time, that rubber tree root traits can be manipulated through intercropping to improve drought resistance. However, our results suggest intercropping might not reduce risks of tree mortality caused by drought in the shallowest soils of the subhumid area of northeast Thailand.

Phytosociology in Degraded and Renewed Pastures in Agrosilvopastoral Systems

ABSTRACT: In pastures, the incidence of weeds reduces the productivity and quality of forage. The identification of the weed species in pastures is fundamental to choose the renewal method. Thus, the objective of this work was to perform phytosociology before and after the renewal of a Brachiaria decumbens pasture, with the implantation of agrosilvopastoral systems. Eighteen different crop arrangements for pasture renewal were evaluated. The renewal systems were by eucalyptus integration (at 12 x 2 m or 12 x 3 m spacings) with maize, Brachiaria brizantha cv. Marandu (palisade grass) and/or Macrotyloma axillare (perennial horsegram), or monoculture and intercropping of palisade grass and perennial horsegram, as well as the evaluation of the application or not of the herbicide bentazon, at the recommended dose for maize crops (0.72 kg ha-1). Relative frequency, relative density, relative abundance, relative dominance, coverage value index, importance value index, dry matter and similarity index were evaluated. In the first survey, before the pasture renewal, 23 plant species were identified. After the implantation of agrosilvopastoral systems, the species Sida cordifolia, Lantana camara and B. decumbens were the only occurring ones before and after the renewal of the pasture with agrosilvopastoral systems. The use of palisade grass and the application of the herbicide were efficient in controlling weeds. In systems that contained palisade grass and perennial horsegram, the latter was not found in the survey conducted one year after the implantation.

Napier Grass: A Model Crop for Developing Partially Weathered Gravelly Land in the Central Deccan Plateau Region

The gravel content in the landscape varies in time and space for the interaction of external factors namely climate and vegetation. The vegetation plays a greater role on gravel disintegration in the landscape at initial stage of soil development can be studied keeping other factors as constant. The objective of this study was to account the change of particle content, particle movements, regolith depth, bulk density, soil organic carbon, cation exchange capacity, pH, mineralizable nitrogen and quantification of both above and below ground biomass production of grasses/fodder crops on the gravelly land. In this regard, locally suitable fodder crops such as napier grass, stylo grass, marvel-stylo grass intercrop and marvel grass were raised. Representative soil samples (45–50 kg) were collected from the surface as well as subsurface layers and separated into different sizes for four consecutive years i.e. 2012–13, 2013–14, 2014–15 and 2015–16. The amount of gravel disintegration decreased with increase in gravel size, time and depth. Overall, the gravel reduction under napier grass, stylo-marvel inter cropping system, stylo and marvel grass cultivation were 91, 65, 52 and 21 g kg−1, respectively higher than that of native fallow land. The increase of soil content, regolith depth, soil organic carbon content and mineralizable nitrogen were highly associated with lowering of gravel content, bulk density and soil pH observed across the treatments. To conclude, cultivation of napier grass may be preferred in barren land for faster disintegration of gravels as well as more fodder production and benefit for the subsequent crops to be taken.

Fertilizing Potential of Separated Biogas Digestates in Annual and Perennial Biomass Production Systems

Digestates produced by the increasing number of biogas plants require appropriate treatment or recycling. This study investigates the fertilizing potential of separated biogas digestates. These contain valuable nutrients and can be used in agriculture to close the nutrient cycle. Multi-year field experiments were established at two challenging sites in south-west Germany in 2010; results from six years are shown here. The objectives were to determine 1) whether separated digestates can complement or substitute mineral fertilizers and 2) their effect on long-term yield performance in different biomass cropping and fertilization systems. The fertilizing performance was assessed in a split-plot design with four replications using three cropping systems: 1) perennial grassland; 2) intercropping of triticale and clover grass; 3) silage maize. Five N fertilization treatments were applied, each at 150 kg N ha-1: mineral fertilizer (calcium ammonium nitrate) combined solid digestate fraction and mineral fertilizer solid digestate fraction combined liquid digestate fraction and mineral fertilizer liquid digestate fraction. The influences of site, cropping system, year and fertilization treatment were highly significant. The mineral fertilizer and combination ‘liquid digestate fraction + mineral fertilizer’ mostly led to the highest quantitative biomass yields in all cropping systems at both sites. Fertilization with solid digestate fraction produced lowest yields in all fertilized plots, with results very often not significantly different from the untreated control. Maize achieved relatively high yields in years with favorable weather conditions; unfavorable conditions led to low yields. The grassland and intercropping systems were less susceptible to weather conditions, producing a more constant biomass supply irrespective of site, treatment and year. The separated biogas digestates were found to have a comparable effect to mineral fertilizer on biomass yield, but this varied with cropping system. In the intercropping system, complete substitution was possible. The solid fraction is more likely to contribute positively to soil humus in annual systems. In general, the combined application of digestate and mineral fertilizer is highly recommendable to meet crops’ short- and long-term N demand, even on challenging sites. In this study, it allowed a mineral fertilizer input reduction of 66%.

Growth and yield of corn forage intercropped with marandu grass in an agrosilvopastoral system with eucalyptus

Corn and grass intercropping is an interesting practice, and forage plants belonging to the genus Urochloa are the most commonly used in these situations. These plants show excellent adaptation to low-fertility soil, easy establishment, considerable biomass production, as well as being an important competitor with weeds. In agrosilvopastoral systems, the yield of corn crops grown together with trees is hindered due to the reduced radiation incidence caused by tree shading. This study aimed to evaluate corn growth, light interception, and chlorophyll content when intercropped with marandu grass in an agrosilvopastoral system with one and three eucalyptus rows, and compare them with plants under full sun. The experiment was conducted in Andradina - SP (Brazil). Treatments consisted of intercropping with no eucalyptus (plants under full sun: control), one system with one eucalyptus row and another with three rows. We also assessed the effect of five distances between corn plants and eucalyptus trees (2, 4, 6, 8, and 10 m). Between eucalyptus rows, corn plants were intercropped with marandu grass. The analyzed variables were corn plant height, ear height, chlorophyll content index, light interception, dry matter, and fresh and dry forage weights. The experimental design was a randomized block in a factorial scheme plus a control, with four repetitions. Tree arrangements had no influence on corn forage, dry matter, plant height, or ear height. Lower results of yield, dry matter, plant height, and ear height were observed for plants spaced 2 m from trees. In the first two evaluations, significant differences of light interception were found for the different distances. Neither tree arrangements (one and three rows) nor the distances from the trees had any impact on corn heights, with no difference between control and the agrosilvopastoral systems. Neither plant distances from trees nor tree arrangements had an influence on chlorophyll content index of corn plants, with no difference between control and the treatments. As a result, corn growth and forage yield under agroforestry systems are similar in arrangements of 1 and 3 eucalyptus rows (15-month-old trees) and under full sun. However, corn dry matter contents were lower in systems containing trees. Intercropping corn and marandu grass in a system without trees increased light interception at harvest time, indicating a larger soil coverage. Corn forage yield and dry matter content were lower when plants were 2 m apart from eucalyptus trees since this condition provided a lower amount of light and greater competition for water and nutrients.

Productivity, Economic, and Environmental Benefits in Intercropping of Maize with Chili and Grass

Core Ideas In upland, how to integrate soil conservation, productivity, and economic benefits is still a challenge. Using a 4‐yr experiment, we found the maize/chili intercropping could be a valuable choice, which decreased erosion and increased economic benefits. The multiple cropping system combined with staple and cash crops should be given greater attention in hilly areas. Intercropping is a widespread cropping system to increase land productivity and decreases soil erosion. However, considering economic benefits of intercropping mountain agriculture is deficient. A field experiment was conducted to determine productivity, economic efficiency, and soil conservation benefits of intercropping of maize (Zea mays L.) with chili (Capsicum annuum L.) and setaria grass (Setaria anceps Stapf ex Massesy) in Yunnan. Runoff, sediment, crop yield, and economic benefits were evaluated under sole maize (SM), sole chili (SC), maize/chili intercropping (MCI), and maize/setaria grass intercropping (MGI). The results suggested that intercropping decreased runoff when compared with sole crop. The MGI had the least sediment, followed by MCI, SM, and SC. Severe soil loss was observed in sole crop systems but not in intercropping systems. Moreover, the land equivalent ratio (LER) of MCI ranged from 1.22 to 1.69, and mean economic income (US$3955 ha−1) were 29.91, 16.38, and 23.41% higher than that of SM, SC, and MGI, respectively. Therefore, MCI can integrate the benefits of productivity, economy, and soil conservation, suggesting that intercropping of maize and chili, a staple‐cash crop pattern, should be favored in mountain agriculture.

Production, nutrient cycling and soil compaction to grazing of grass companion cropping with corn and soybean

Agricultural management systems are needed to simultaneously enhance production, promote plant diversity, improve nutrient cycling and reduce soil compaction. We investigated the effects of intercropped forage grass on production of corn (Zea mays L.) harvested for silage at 0.20 and 0.45 m height in the summer, as well as on production of subsequent forage, soybean [Glycine max (L.) Merr.] harvested for silage, nutrient cycling and soil responses on a Typic Haplorthox in Botucatu, Sao Paulo State, Brazil. Palisade grass cv. BRS Piata [Urochloa brizantha cv. BRS Piata] was the introduced companion crop with corn (Years 1 and 2), while signal grass [Urochloa decumbens cv. Basilisk] was the residual weedy species in comparison. Guineagrass cv. Aruana [Megathyrsus maximus cv. Aruana] was the introduced companion crop with soybean (Year 3), with only a residual effect of crop systems from the previous two years. After the corn silage harvest, pasture was grazed by lambs in winter/spring using a semi-feedlot system. When cut at 0.45 m compared with 0.20 m height, corn intercropped with palisade grass had greater leaf nutrient concentration, improved agronomic characteristics, forage mass of pasture for grazing by lambs, greater surface mulch produced, and greater quantity of N, P and K returned to soil. Greater soil organic matter, P, K and Mg concentration, and base saturation in the surface soil depth and lower soil penetration resistance at all depths occurred at 0.45 m than at 0.20 m corn silage cutting height intercropped with palisade grass. Analyzing the system as a whole, harvesting corn silage crop with palisade grass intercrop at 0.45 m height was the most viable option in this integrated crop-livestock system.

Production and Soil Responses to Intercropping of Forage Grasses with Corn and Soybean Silage

Agricultural management systems are needed to simultaneously enhance production, and improve soil quality. We investigated the effects of intercropped grass on production of corn (Zea mays L.) harvested for silage at 0.20 and 0.45 m height in the summer, as well as on production of subsequent forage, silage soybean [Glycine max (L.) Merr.], and soil responses on a Typic Haplorthox in Botucatu, SP, Brazil. Palisade grass [Urochloa brizantha (Hochst. ex A. Rich.) R. Webster ‘Marandu’] was the introduced companion crop with corn (Years 1 and 2), while signal grass [Urochloa decumbens (Stapf) R. Webster ‘Basilisk’] was the residual weedy species in comparison. Guinea grass [Urochloa maxima (Jacq.) R. Webster ‘Aruãna’] was the introduced companion crop with soybean (Year 3), with only a residual effect of crop systems from the previous 2 yr. When cut at 0.45 m compared with 0.20 m height, corn intercropped with palisade grass had greater leaf nutrient concentrations, agronomic characteristics, forage mass of pasture for grazing by lambs (Ovis aries), greater surface mulch produced, and greater quantity of N, P, and K returned to soil. Greater soil organic matter, P, K, and Mg concentration, and base saturation in the surface soil depth and lower soil penetration resistance at all depths occurred at 0.45 m than at 0.20 m corn silage cutting height intercropped with palisade grass. Analyzing the system as a whole, harvesting corn silage crop with palisade grass intercrop at 0.45 m height was the most viable option in this integrated crop–livestock system (ICLS).Core Ideas Agricultural management systems are needed to enhance production and improve soil quality. After corn silage harvest, pasture was grazed by lambs in winter/spring using a semi‐feedlot system. Harvesting corn silage crop with palisade grass intercrop at 0.45 m height was the most viable option.

Effect of different spacing of Napier grass (Pennisetum purpureum) intercropped with or without Lablab (Lablab purpureus) on biomass yield and nutritional value of Napier grass

This study was conducted with an objective of determining effect of three spacing of Napier grass intercropped with or without Lablab (Lablab purpureus) on the biomass yield and nutritive value of Napier grass forage in a 2 x 3 factorial arrangement in RCBD with 4 blocks. Spacing was 1m x 0.5m, 0.75m x 0.5m, and 0.5m x 0.5m. Intercropping decreased the electro conductivity but increased the available phosphorous content of the soil and did not affect the pH, organic carbon and total nitrogen of the soil. Spacing, intercropping and their interaction had no significant effect (P>0.05) on dry matter (DM) yield (DMY) and crude protein (CP) yield (CPY) of the Napier grass. Intercropping and interaction of intercropping with spacing resulted to higher total DMY and CPY (P<0.05). The chemical composition of Napier grass was unaffected by spacing and interaction of intercropping with spacing. Intercropping of Napier grass with lablab however, increased the DM contents (P<0.05) of the Napier grass and decreased the ash contents. In conclusion, intercropping with lablab had a positive influence on the TDMY, TCPY, DM, hence increase the total forage yield and nutritive value of Napier grass. Conversely, spacing failed to have significant impact on these parameters. As such 1 m x 0.5m spacing and intercropping with lablab can be of a better choice based on the results of this study.

Nitrogen and phosphorus losses by runoff erosion: Field data monitored under natural rainfall in Three Gorges Reservoir Area, China

Nitrogen (N) and phosphorous (P) from agricultural non-point source (ANPS) pollution are the great threats to the regional water quality in the Three Gorges Reservoir Area (TGRA) of China. To explore the pollution of N and P loss from the sloping land in TGRA agricultural areas, field-scale plot experiment under natural rainfall was conducted from May 1 to October 31 in 2012. We monitored and analyzed rainfall, runoff volume, sediment yield, and nutrient concentration under different conditions (3 soil types, 3 surface slopes, and 5 cropping systems) in 30 experimental plots of 20m2 during the rainy season. The results indicated that average loss ratio of N was 1.90%, while that of P was 1.54%. N and P loss ratios from surface runoff in 15° plots of sloping farmland were the highest. Purple soil (PS) was the most severe soil and nutrient loss. Within all the 5 cropping systems, the loss ratios of N and P from intercropping of citrus and grass (C-G) were the lowest. The practice of C-G, which was the most beneficial cropping system, should be further encouraged especially in TGRA to cope with the serious issues of N and P losses. These findings provide useful and valuable information for decision makers and planners to take sustainable measures for the control of ANPS pollution in TGRA, and are beneficial for the agro-ecological environment management of the local agricultural watersheds.

Annual crop rotation of tropical pastures with no-till soil as affected by lime surface application

Abstract Soil acidity and low natural fertility are the main limiting factors for grain production in tropical regions such as the Brazilian Cerrado. The application of lime to the surface of no-till soil can improve plant nutrition, dry matter production, crop yields and revenue. The present study, conducted at the Lageado Experimental Farm in Botucatu, State of Sao Paulo, Brazil, is part of an ongoing research project initiated in 2002 to evaluate the long-term effects of the surface application of lime on the soil’s chemical attributes, nutrition and kernel/grain yield of peanut (Arachis hypogaea), white oat (Avena sativa L.) and maize (Zea mays L.) intercropped with palisade grass (Urochloa brizantha cv. Marandu), as well as the forage dry matter yield of palisade grass in winter/spring, its crude protein concentration, estimated meat production, and revenue in a tropical region with a dry winter during four growing seasons. The experiment was designed in randomized blocks with four replications. The treatments consisted of four rates of lime application (0, 1000, 2000 and 4000 kg ha−1), performed in November 2004. The surface application of limestone to the studied tropical no-till soil was efficient in reducing soil acidity from the surface down to a depth of 0.60 m and resulted in greater availability of P and K at the soil surface. Ca and Mg availability in the soil also increased with the lime application rate, up to a depth of 0.60 m. Nutrient absorption was enhanced with liming, especially regarding the nutrient uptake of K, Ca and Mg by plants. Significant increases in the yield components and kernel/grain yields of peanut, white oat and maize were obtained through the surface application of limestone. The lime rates estimated to achieve the maximum grain yield, especially in white oat and maize, were very close to the rates necessary to increase the base saturation of a soil sample collected at a depth of 0–0.20 m to 70%, indicating that the surface liming of 2000 kg ha−1 is effective for the studied tropical no-till soil. This lime rate also increases the forage dry matter yield, crude protein concentration and estimated meat production during winter/spring in the maize-palisade grass intercropping, provides the highest total and mean net profit during the four growing seasons, and can improve the long-term sustainability of tropical agriculture in the Brazilian Cerrado.

Enhancing Soil Fertility through Intercropping, Inoculation and Fertilizer

The present study was conducted to investigate the effects of intercropping grass (Panicummaximum) and legumes (Vicia sativa and cowpeas) alone or coupled with inoculation or fertilizer on soilfertility. The study comprised of two field experiments conducted under rain fed conditions for two years(June, 2005 to September, 2007) at National Agriculture Research Centre, Islamabad, Pakistan. In oneexperiment intercropping (33, 50 and 67%) of grass and legumes alone as well as coupled with seedinoculation were studied while, same set of treatments was combined with fertilizer application at the ratesof 25, 75 and 50 kg/ha (N, P2O5 and K2O) in the second experiment. Total soil N increased by 0.008% dueto symbiotic fixation in addition to plant uptake under best treatment when compared with grass alonewhile, soil organic matter increased by 0.19%. After crop harvest soil N content was determined to behigher in all the treatments of the experiment compared with growing grass alone. Legumes caused rhizobialN fixation that caused an increase in soil N. Similarly, intercropping and inoculation increased this soilcharacteristic that was found to be non-significant in the first crop but later on became significant, especiallywhen intercropping of grass with legumes after seed inoculation was investigated or fertilizer wassupplemented to the crops. Thus, not only grass used the symbiotically fixed N by companion legumesbut also enhanced the soil N content. The effect of fertilizer was not measurable statistically in case of soilorganic matter. This parameter, in general, was not affected significantly when assessed after first cropharvest. Nevertheless, legumes alone or intercropped within grass increased this important soil constituent.Inoculation proved further beneficial in this regard but combination of intercropping (especially 67%)either with seed inoculation or application of fertilizer was found as the best technique for increasing soilorganic matter.