Sole Maize Crop Research Articles

Effect of planting patterns and weed management practices on weed dynamics and nutrient mining in runner bean (Phaseolus coccineus L.) + Maize (Zea mays L.) intercropping

A field experiment entitled “Planting pattern and weed management in maize (Zea mays L.) + runner bean (Phaseolus coccineus L.) intercropping system” was conducted during the rabi season of 2016-17 at Agronomy Main Research Farm, Bhubaneswar. The experiment was laid out in split plot design with planting patterns in the main plot and weed management practices in the sub plot. ‘Shriram 9220’ maize hybrid and ‘Raikia local’ variety of runnerbean were used as test crops. The study revealed that P4- maize 100% + runner bean 100% in the same row recorded the minimum weed density and dry weight and maximum weed smothering efficiency. While, weed management practices, W3-Pendimethalin 1.0 kg/ha + 1 manual weeding also recorded the minimum weed density and dry weight and maximum weed control efficiency. Significantly higher nutrient of content in the maize grain and stover was recorded in maize 100% + runner bean 50% in separate rows among planting patterns and W3-pendimethalin 1.0 kg/ha + one manual weeding at 25 DAS among weed management practices. For runner bean, maize 100% + runner bean 100% in same row gave significantly higher pod and haulm nutrient content. However, the maximum uptake of N, P and K was in sole crops of runner bean and maize respectively due to its higher yield.

Effects of Genetically Modified (GM) Maize Adoption in Small Scale Farms on Cropping Systems of the Eastern Cape Province, South Africa

Genetically modified (GM) crops are being promoted to ensure agricultural productivity and food security to keep pace with the ever-growing global population and food demand. In as much as agricultural technological advancements are crucial, there is need to strike a balance with agrobiodiversity for sustainable farming. Surveys were conducted in five municipal districts of the Eastern Cape Province to determine GM-technology adoption effects on maize cropping systems, agronomic practices and farmers’ perceptions of production constraints. Interviews of 232 farmers, independent (IF) 22.4% and government sponsored (GCP) 77.6%, revealed a wide variation in agronomic practices amongst them. Results indicate significant differences on the maize cropping systems practiced by the Eastern Cape small scale farmers. The majority (81.7%) of interviewed small scale GCP farmers produce maize as a monocrop, under dryland (91.7%) through conventional tillage practices (100%). In contrast, IF farmers practiced maize sole cropping (34.6%), under dryland (90.4%) through conventional tillage practices (86.5%). There were significant differences between the two farmers’ groups on crop mixture used (p=0.00), crop rotations (p=0.02), choice of maize varieties (p=0.00) and fertiliser use (p=0.00). Demographic and farm characteristics, type of land cultivation, production constraints, pest problems and pest management practices are discussed. The findings suggest the need to devise a system that will improve compatibility of GM-maize technology and traditional farming practices to ensure sustainable farming and food security for the resource poor farmers. The government support schemes seeking to enhance agricultural productivity need to equip farmers with the necessary versatile farming skills.

Performance of Legumes on Weed Suppression with Hybrid Maize Intercropping

Field experiment was carried out at the Bangladesh Agricultural Research institute, Joydebpur, Gazipur during 2010 to 2011 to identify suitable legume crops with maize in maize + legume intercropping systems for better weed suppression, productivity and economic benefits in Rabi season. There were 17 treatments of which two sole crop of hybrid maize (Zea mays BARI Hybrid bhutta -9) (weed free and no weeding), three weed free sole crops of pea (SN), bushbean (SN) and cowpea (SN) in Rabi season, and their intercropping. Twelve intercropping with different weeding regimes (no weeding, one hand weeding at 20 days after emergence (DAE), one hand weeding at 40 DAE, and two hand weeding at 20 and 40 DAE of maize-legume intercropping under normal row (75 cm Î 25 cm), and two rows of legumes in between two rows of maize were used . Among all intercropping, maize-pea with two hand weeding at 20 and 40 DAE gave the lowest (6.57 g m-2 at harvest) weed dry weight and the highest weed control efficiency (86% at harvest). Maize-pea with two hand weeding at 20 and 40 DAE gave the highest yield (maize: 7.58 t ha-1; 6.27 t ha-1 pea), resource complementarily and profitability (LER = 1.89, BCR = 4.19). Intercropping of two rows of pea in between two rows of maize with two hand weeding at 20 and 40 DAE to be a promising practice for weed suppression and profitable maize + legume intercropping in Rabi season.
 Bangladesh Agron. J. 2018, 21(2): 33-44

Narrow‐wide‐row planting pattern increases the radiation use efficiency and seed yield of intercrop species in relay‐intercropping system

AbstractPlanting arrangements affect radiation use efficiency (RUE) and competitiveness of intercrop species in intercropping systems. Here, we reveal that narrow‐wide‐row planting arrangement in maize‐soybean relay‐intercropping system increases the dry matter and competitiveness of soybean, increased the RUE of maize and soybean, and compensates the yield loss of maize by substantially increasing the yield of soybean. In this field study, maize was planted with soybean in different planting arrangements (P1, 20:180, P2, 40:160; P3, 60:140, and P4, 80:120) of relay intercropping, all the relay‐intercropping treatments were compared with sole crops of maize (SM) and soybean (SS). Results showed that P1 improved the total RUE 3.26 g/MJ (maize RUE + soybean RUE) of maize and soybean in relay‐intercropping system. Compared to P4, treatment P1 increased the soybean competition ratio (CR) values (by 55%) but reduced the maize CR values (by 29%), which in turn significantly improved the yield of soybean by maintaining the maize yield. Generally, in P1, soybean produced 82% of SS yield, and maize produced 88% of SM yield, and it achieved the land equivalent ratio of 1.7. These results suggest that by maintaining the appropriate planting distances between maize and soybean we can improve the competitiveness and yield of intercrop species in relay‐intercropping system.

Optimum Sowing Dates for High-Yield Maize when Grown as Sole Crop in the North China Plain

The maize sole cropping system solves problems related to ground water resource shortages and guarantees food security in the North China Plain. Using optimal sowing dates is an effective management practice for increasing maize yield. The goal of this study was to explore an optimum sowing date for high-yield maize. Six sowing dates (SDs) from early April to late June with intervals of 10 to 20 days between SD—SD1 (early April), SD2 (mid to late April), SD3 (early May), SD4 (mid to late May), SD5 (early June), SD6 (late June)—were applied from 2012 to 2017. The results showed that yield was correlated with the sowing date based on the thermal time before sowing (r = 0.62**), which was defined as the pre-thermal time (PTt), and that the yield was steadily maintained at a high level (>10,500 kg ha−1) when PTt was greater than 479 °C. To satisfy the growing degree-days required for maturity, maize needs to be sown before a PTt of 750 °C. Data analysis of the results from 2014, 2015, and 2017 revealed the following: i) Most of the grain-filling parameters of late-sown dates (SD4, SD5 and SD6) were better than those in early-sown dates (SD1, SD2, and SD3) in all years, because of the high daily maximum temperature (Tmax) and wide diurnal temperature (Td) from silking to blister (R1–R2) of early-sown dates. The weight of maximum grain-filling rate (Wmax) of SD3 decreased compare with SD4 by the narrow Td from blister to physiological maturity (R2–R6) in all years (−5, −12, and −33 mg kernel−1 in 2014, 2015, and 2017, respectively). ii) In 2017, the pollination failure rates of early-sown dates were 8.4~14.5%, which was caused by the high Tmax and Td of R1–R2. The apical kernel abortion rates were 28.6 (SD2) and 38.7% (SD3), which were affected by Tmax and Td during R2–R6. iii) Compared with late-sown dates, the wide Td of early-sown dates in R1–R2 was caused by higher Tmax, but the narrow Td in R2-R6 was caused by higher Tmin. Our results indicate that high-yielding maize can be obtained by postponing the sowing date with a PTt of 480~750 °C, which can prevent the negative effects of the high Tmax of R1–R2 and high Tmin of R2–R6 on kernel number and weight formation. Moreover, these above-mentioned traits should be considered for heat tolerance breeding to further increase the maize yield.

Effect of planting patterns on yield, nutrient accumulation and distribution in maize and soybean under\xa0relay intercropping systems

Planting patterns affect nitrogen (N), phosphorus (P), and potassium (K) acquisition and distribution in maize and soybean under intercropping conditions. Here we reveal that strip relay-intercropping increases the N, P, and K uptake and distribution across plant organs (root, straw, and seed) of maize and soybean, accelerates the dry-matter production of intercrop-species, and compensates the slight maize yield loss by considerably increasing the soybean yield. In a two-year experiment, soybean was planted with maize in different planting patterns (SI, 50:50 cm and SII, 40:160 cm) of relay-intercropping, both planting patterns were compared with sole cropping of maize (SM) and soybean (SS). As compared to SI, SII increased the N, P, and K accumulation in each organ of soybean by 20, 32, and 18 (root) %, 71, 61, and 76 (straw) %, and 68, 65, and 62 (seed) %, respectively, whereas decreased the N, P, and K accumulation in each organ of maize by 1, 4, and 8 (root) %, 1, 10, and 3 (straw) %, and 5, 10, and 8 (seed) %, respectively. Overall, in SII, relay-cropped soybean accumulated 91% of total nutrient uptake (TNU) of sole soybean plants, and relay-cropped maize accumulated 94% of TNU of sole maize plants.

Narrow-wide row planting pattern improves the light environment and seed yields of intercrop species in relay intercropping system.

Different planting patterns affect the light interception of intercrops under intercropping conditions. Here we revealed that narrow-wide-row relay-intercropping improves the light interception across maize leaves in wide rows (60cm) and narrow rows (40cm), accelerated the biomass production of intercrop-species and compensated the slight maize yield loss by considerably increasing the soybean yield. In a two-year experiment, maize was planted with soybean in different planting patterns (1M1S, 50:50cm and 2M2S, 40:60cm) of relay-intercropping, both planting patterns were compared with sole cropping of maize (M) and soybean (S). As compared to M and 1M1S, 2M2S increased the total light interception of maize leaves in wide rows (WR) by 27% and 23%, 20% and 10%, 16% and 9% which in turn significantly enhanced the photosynthetic rate of WR maize leaves by 7% and 5%, 12% and 9%, and 19% and 4%, at tasseling, grain-filling and maturity stage of maize, respectively. Similarly, the light transmittance at soybean canopy increased by 218%, 160% and 172% at V2, V5 and R1 stage in 2M2S compared with 1M1S. The improved light environment at soybean canopy in 2M2S considerably enhanced the mean biomass accumulation, and allocation to stem and leaves of soybean by 168%, and 131% and 207%, respectively, while it decreased the mean biomass accumulation, and distribution to stem, leaves and seed of maize by 4%, and 4%, 6% and 5%, respectively than 1M1S. Compared to 1M1S, 2M2S also increased the CR values of soybean (by 157%) but decreased the CR values of maize (by 61%). Overall, under 2M2S, relay-cropped maize and soybean produced 94% and 69% of the sole cropping yield, and the 2M2S achieved LER of 1.7 with net income of 1387.7 US $ ha-1 in 2016 and 1434.4 US $ ha-1 in 2017. Our findings implied that selection of optimum planting pattern (2M2S) may increase the light interception and influence the light distribution between maize and soybean rows under relay-intercropping conditions which will significantly increase the intercrops productivity. Therefore, more attention should be paid to the light environment when considering the sustainability of maize-soybean relay-intercropping via appropriate planting pattern selection.

Maize-lupine intercrop response to applied nitrogen and phosphorus in North-Western Ethiopia

Maize (Zea mays) is a major staple crop in North-Western Ethiopia. Narrow leaf lupine (Lupinus angustifolius) grain is a commercial concentrates for livestock feed. Maize-lupine intercropping is a sustainable and emerging crop production approach for the resource poor smallholder farmers of North-Western Ethiopia; however, there is no recommended fertilizer rate for the intercrop. Therefore, field experiment was undertaken to determine maize-lupine intercrop yield response to applied N and P; to determine N use efficiency of maize; and to establish the basis for determining the most economical N and P rates with varying costs and commodity prices for the intercrop. The experiment was conducted at South Achefer and Mecha areas of North-Western Ethiopia in 2013 crop season. Four levels of each N (0, 64, 128 and 192 kg N ha-1) and P (0, 20, 40 and 60 kg P ha-1) were arranged in factorial combination. Sole crop maize and lupine were included as check treatments. The treatments were laid out in a randomized complete block design with three replications. The results indicated that maize growth parameters and yield components, maize grain yield, and total maize-lupine intercrop yield increased significantly with applied N, P, and N x P interactions. The highest total intercrop yields were obtained on 162/45 kg N/P ha-1 at South Achefer and 205/61 kg N/P ha-1 at Mecha with yield advantage of 4.14 and 7.05 t ha-1 over unfertilized, respectively. The economic optimum rates for maize-narrow leaf lupine intercrop were 130/39 kg N/P ha-1 at South Achefer and 177/53 kg N/P ha-1 at Mecha with cost price ratio of N cost kg-1/maize grain price kg-1 equal to 6 and P cost kg-1/maize grain price kg-1 equal to 11. The economic optimum rates decreased as cost price ratio increased, therefore, seasonal price information is vital to adjust the economic optimum rates. Maize N use efficiency declined as N rates increased in the maize-lupine intercrop. Key words: Intercropping, lupine, maize, optimum rate, yield response.

Row Arrangements of Maize and Soybean Intercrop on Silage Quality and Grain Yield

The success of maize + soybean intercrop depends on the plant arrangement. An experiment was carried out to evaluate different row arrangements on intercrop forage yield, silage quality and maize grain yield in relation to maize as a sole crop. The experiment was set up with a randomized complete block design with eight row arrangements between maize and Soybean. Maize biomass yield among crop arrangements were similar, although, lower than the maize sole crop. On the other hand, these treatments showed higher soybean biomass yield, which in turn increased silage crude protein and crude protein yield per unit area. Maize thousand grain weight, grain yield per plant and per area was affected by the intercrop arrangements. The use of two corn rows + two soybean rows (2M+2S-30 cm) and four corn rows + four soybean rows (4M+4S-30 cm) showed higher crude protein yield per area associated with similar maize grain yield in relation to the sole maize crop. In conclusion, alternating four maize rows with four soybean rows was the optimum row ratio in maize + soybean intercrop, though this needs to be further confirmed by more trials.

Agronomic Practices of Maize and Farm Nutrient Status in Bako Tibe District, West Shoa Zone, Ethiopia: Lesson from Agronomic Panel Survey

Agronomic panel survey was conducted in Bako Tibe district to assess current farmers maize agronomic practices and associated actual maize grain yields. The survey was conducted using 100 households. Most of the maize farms (90%) were characterized as having strongly to strongly acidic soils, low to medium SOC, medium to high TN, very low to low av.P, high to very high exch. K, low to medium exch.Ca, and medium to high exch. Mg, high av. Zn and Fe and very high Mn contents. Most farmers (94%) grow improved maize varieties and 80% of them grew a pioneering hybrid Limu and Bako hybrids BH540 and BH543. Most farmers (97%) apply different inorganic fertilizers and of them >70% of them applied NPS+Urea or NPS alone. Farmers rarely retain crop residue. Most farmers (81%) maintain lower plant density at harvest than the recommended density and the density declined from vegetative to harvesting stage. About 99% of the farmers grow sole maize, 57% rotate maize with other. Percent weed cover of the farms were 25% on average but reached as high as 80%. About 87.5%, 86%, 75% of farmers harvested grain yield that was higher than the national, regional and zonal average, respectively. Since most maize farms (90%) were very strongly to strongly acidic, there is a need to apply lime to improve maize productivity and nutrient use efficiency in the area. The poor weed and crop residue management, sole cropping of maize and lower plant densities practiced by farmers were among the gaps observed that potentially reduce maize productivity in the study area unless the extension sector intervenes. However, the current trend improved maize varieties and inorganic fertilizers use is promising and needs to be encouraged for intensification of maize production in the study area.

Intercropping of maize, millet, mustard, wheat and ginger increased land productivity and potential economic returns for smallholder terrace farmers in Nepal

Low nitrogen inputs, low crop yield, and low land productivity are major challenges associated with cereal-based sole cropping systems in Nepal. Crop intensification and diversification by introducing legumes as intercrops could help alleviate these challenges. With the presence of diverse crops and cropping systems, particularly in hilly topographies, a range of intercrop options is required. We compared 10 intercrop combinations to native sole cropping systems in the mid-hills of Nepal for two cropping seasons (2015–2017) to identify the most productive and economic intercrop combinations for smallholder terrace agriculture. In the spring-summer season (i.e., mid-March to mid-July), cowpea (var. Makaibodi and Suryabodi) and bean were intercropped with maize in 1:1 rows, whereas soybean, blackgram, and horsegram were broadcast with millet (30:70 ratios) during the rainy-autumn season (i.e., mid-July to mid-November). Pea and lentil were used as pre-winter/winter intercrops (i.e., mid-November to mid-March) in mustard (30:70 ratios), while wheat was planted with pea. Ginger was planted with maize in 1:1 rows during the spring-summer season in which the maize rows were replaced by soybean and lentil during the rainy-autumn and pre-winter/winter season, respectively. Plots were analyzed for yields of individual crops as well as other agronomic indicators including land equivalent ratio (LER), total land output (TLO), harvest index (HI), and potential economic return.Maize + cowpea var. Makaibodi appeared to be the most productive and economic intercrop combination for the spring-summer season (LER – 1.58 and TLO – 4.26 t ha−1, 21% higher than the maize sole crop with an increase in potential economic return by 67%) whereas millet + soybean appeared to be the best combination for the rainy-autumn season (LER – 1.40 and TLO – 2.21 t ha−1, 26% higher than the millet sole crop with a 288% increase in potential income). For the pre-winter/winter season, wheat + pea and mustard + pea combinations appeared to be productive (wheat + pea: LER – 1.31 and TLO – 2.90 t ha-1 i.e., 16% higher than sole wheat with a 54% increase in potential income; mustard + pea: LER – 1.36 and TLO – 2.14 t ha−1 i.e., 30% higher than sole mustard with a 15% increase in potential income). The year round intercrop system (i.e., ginger + maize-soybean) displayed a LER value of 2.45 with increased TLO (21.8 t ha−1 i.e., 2% higher compared to sole ginger) which increased potential economic return by 6%. We conclude that legume intercropping was a robust option across seasons and locations confirming that it could be a promising ecological practice for intensification of cereal-based sole cropping systems on smallholder terraces. Also, it is important to note that soybean and pea provided higher potential net income to farmers as sole crops compared to when they were grown with millet and wheat as intercrops, respectively. It is important that we promote these options to smallholder farmers and disseminate the advantages of legume integration on land productivity, soil fertility management, and income.

Does maize and legume crop residue mulch matter in soil organic carbon sequestration?

Soil management techniques, such as mulching, are used to enhance soil organic carbon sequestration. However, we demonstrate that the potential of crop residue mulching to increase soil organic carbon (SOC) sequestration varies by cropping system and soil type in Austrian agricultural soils. Effects of mulch (as harvested crop residues applied at 1.0 t C ha−1) on soil and microbial carbon (C) and nitrogen (N) and soil δ13C were measured in an Austrian Cambisol field experiment with sole maize or vetch or vetch-maize rotation cropping systems after five years with or without mulching to elucidate how SOC is affected. The direct role of mulch on SOC in different soil types was also investigated in a similar greenhouse mesocosm study with controlled moisture using the same Cambisols and an Austrian agricultural Chernozem. Only sole maize cropping in the field experiment resulted in higher SOC with mulching and when legumes were included in a legume-maize rotation SOC did not improve. Mulching in the field experiment only resulted in higher SOC in the top 0–5 cm of soils with sole maize cropping (by 22%) compared to soils without mulch. Although mulch did not increase SOC in vetch-maize rotation, the δ13C of SOC was less negative with mulch indicating larger C contribution from maize than vetch mulch. After four years of annual soybean-maize rotation in the mesocosm experiment, no significant differences in SOC were observed in Cambisols with or without mulch. Again, δ13C of both soil types was less negative with mulching indicating a larger C contribution from maize than soybean mulch. No relationships between microbial biomass C and N and SOC were observed in either experiment and only soil N concentration was positively correlated with SOC. Together these studies indicate that maize can increase SOC when crop residues are applied in Austrian Cambisols but that inclusion of legume production and legume mulch in rotation can mute these benefits.

English

A study was carried out in 2011/2012 and 2012/2013 growing seasons in Kandeu and Manjawira Extension Planning Areas (EPAs) in Ntcheu district, Central Malawi, to determine maize response to crop residue incorporation from legume cropping systems and compost manure. In 2011/2012 growing season, maize with or without compost manure, sole and intercropped legumes (pigeon pea, groundnut, soyabean and cowpea) were planted.  In 2012/2013 growing season, maize was planted as a test crop to assess its response to residues from legumes after harvest and N fertiliser. The experiment was laid out in a randomised complete block design, replicated 38 times. Maize grain yields following incorporation of legume crop residues were 1000 kg higher than from continuous sole cropped maize in both Kandeu and Manjawira EPAs, (p <0.001). There was no significant difference in maize grain yield following sole and doubled-up legumes. Grain yield of sole-cropped unfertilised maize, maize with inorganic fertiliser and compost manure were significantly different (p<0.001) across farms in Kandeu EPA, with an average of 3159 kg for fertilised (92 kg N ha-1) maize. Grain yield following sole groundnuts and top dressed with 23 kg N ha-1 was higher (3542 kg) compared to maize fertilised with 92 kg N ha-1 (3159 kg) in Kandeu EPA. Risk assessment showed that maize grain yield from maize following sole cowpea, sole pigeonpea, sole soya bean, pigeonpea intercropped with cowpea and groundnut intercropped, and maize with compost manure was equal to or more than 1300 kg  ha-1 at 25% risk. This grain yield was above that of continuous maize with 92 kg N ha-1, and paused less risk of harvesting maize grain below the recommended grain requirement. This suggest that organic matter addition from various legume cropping system, supplemented with low nitrogen inputs from inorganic fertiliser, offer a viable option for improving maize grain yield rather than depending on inorganic fertiliser alone. Key words: Crop residues, doubled-up legumes, grain legumes, intercropping, risk assessment.

Relay strip intercropping of oat with maize, sunflower and mung bean in semi-arid regions of Northeast China: Yield advantages and economic benefits

Intercropping is a sustainable agriculture system that provides an alternative pathway to combat environmental deterioration due to excessively intensive agriculture. However, relay strip intercropping patterns have rarely been practiced in the semi-arid regions of Northeast China. Therefore, two years of field experiments of oat/maize, oat/sunflower, and oat/mung bean relay strip intercropping were conducted to determine the optimal yields and economic patterns. Treatments included sole crops of oat, maize, sunflower and mung bean, as well as three relay strip intercropping patterns consisting of six rows of oat alternating with three rows of maize, sunflower, or mung bean. The land equivalent ratio (LER) of intercrops varied from 1.10 to 1.14, 1.23 to 1.38, and 1.05 to 1.08 for oat/maize, oat/sunflower, and oat/mung bean, respectively. Relay strip intercropping systems presented distinct yield advantages, especially in oat/sunflower. The net incomes of oat/sunflower intercropping were estimated to be ∼2000 $ ha−1, which were significantly higher than both sole oat and sunflower. In oat/sunflower intercropping, kernel numbers per ear, ear numbers per meter row of oat and the thousand kernel weight of sunflower in border rows were 16–25%, 23–30% and 10–13% higher than inner row, well as thousand kernel weight of sunflower in border row increased 10–13% than inner rows, respectively. However, no positive border row effects were observed in the oat/maize or oat/mung bean intercropping systems. In conclusion, oat/sunflower relay strip intercropping is the most profitable alternative intercropping pattern in the semi-arid regions of Northeast China.

Maize Sole Crop and Intercrop Response to Fertilizer in Mali and Niger

Core Ideas Applying N for maize production in semi‐arid west Africa can be profitable.The profit potential of N application is great for maize–groundnut intercrop.Application of P and K has low and inconsistent profit potential for maize production in semi‐arid west Africa.Nutrient response functions can be determined for maize–groundnut intercrop from maize sole crop data. Maize (Zea mays L.) is important in semiarid West Africa where the increase in demand exceeds the increase in production. Yield is often constrained by inadequate nutrient availability even though the occurrence of soil water deficits may overall be more constraining. Research was conducted in semiarid Mali and Niger to determine the yield and profit responses of maize sole crop (MzSC) to N, P, and K and to develop a procedure for determining maize–groundnut (Arachis hypogaea L.) intercrop (MzGnI) nutrient response functions from MzSC functions. Trials were conducted in 2014 and 2015 at five locations spanning 14 degrees of longitude and two degrees of latitude. Mean MzSC grain yield increase due to 50 kg ha−1 N was 0.69 Mg ha−1 in Mali and 0.42 Mg ha−1 in Niger, and due to 10 kg ha−1 P was 0.14 Mg ha−1 in Niger with inconsistent P effects in Mali. Responses to K were negligible. Productivity and profit potential with N application was more with MzGnI compared with MzSC, but profit potential for applied P and K were not improved with MzGnI. Considering the fodder value of stover added to production value but did not have much effect on profits from fertilizer use. The procedure for determining MzGnI nutrient response functions by adapting MzSC functions was developed, providing a means to improve fertilizer use efficiency for MzGnI. Productivity and returns to applied N, on a maize grain value equivalent, are greater with MzGnI compared to MzSC.

Comparative analysis on the profitability of sole maize cropping and maize/melon intercrop in Osun State, Nigeria

Profitability is a motivational factor in any enterprise. The study compared the profitability of sole maize and maize/melon intercrop in Osun State. A purposive sampling technique was used and primary data collected with the aid of a structured questionnaire. Descriptive statistics, budgetary technique, inferential statistics and regression techniques were used to analyse the data collected. The majority of the respondents were active, male, had formal education and had less than 21 years of experience in cropping systems. The estimated net return to management was N59,323.83 per sole maize farmer or N37, 548.75 per hectare per year and N175,178.68 per farmer or N102, 832.17 per hectare for maize/melon. Budgetary analysis results showed that both sole maize and maize/melon intercrop were profitable. The multiple regressions for maize/melon intercrop revealed that 94.2% of variation in profit was obtained by independent variables in the model. The multiple regressions for the sole maize profit function revealed that 62.3% of variation in profit was obtained by independent variables in the model. The costs of input used, labour employed and quantity sold were the major determinants of profitability. The appropriate policies to enable the farmers to have access to inputs at a subsidised rate should be put in place.

MAIZE–SOYBEAN INTERCROPPING FOR SUSTAINABLE INTENSIFICATION OF CEREAL–LEGUME CROPPING SYSTEMS IN NORTHERN NIGERIA

SUMMARYField studies were conducted during the 2014 and 2015 wet seasons at Zaria in the northern Guinea savanna and at Iburu in the southern Guinea savanna of Nigeria to determine the productivity of maize–soybean intercropping system. There were four treatment combinations in the experiment: sole maize; sole soybean; maize spaced at 50 cm and intercropped with soybean; and maize spaced at 65 cm and intercropped with soybean. The experiment was laid out in a randomized complete block design with three replications. The results showed that sole cropped maize and soybean generally outperformed the intercropped component crops. Land Equivalent Ratio (LER) was greater than 1 for all the intercrop treatments, indicating that it is advantageous to grow maize and soybean in association than in pure stands. Except for 2014 in Zaria, LER for intercropped maize spaced at 50 cm was higher than that for maize spaced at 65 cm. Gross Monetary Value (GMV) was generally higher for intercrops than sole crops except in Iburu in 2015 where GMV for intercropped maize spaced at 65 cm was similar to those of sole maize and soybean. Monetary Advantage Index (MAI) was positive for all intercrop treatments in both locations and years, which shows definite yield and economic advantages compared to the sole cropping systems. This suggests that farmers can intercrop soybean and maize with maize spaced at 50 cm and 65 cm.

N2-fixation and N contribution by grain legumes under different soil fertility status and cropping systems in the Guinea savanna of northern Ghana

Continuous cereal-based cropping has led to a rapid decline in soil fertility in the Guinea savanna agro-ecological zone of northern Ghana with corresponding low crop yields. We evaluated the effects of cropping system and soil fertility status on grain yields and N2-fixation by grain legumes and net N contribution to soil fertility improvement in contrasting sites in this agro-ecological zone. Maize was intercropped with cowpea, soybean and groundnut within a row, with a maize stand alternated with two equally spaced cowpea or groundnut stands and in the maize-soybean system, four equally spaced soybean stands. These intercrops were compared with sole crops of maize, cowpea, soybean and groundnut in fertile and poorly fertile fields at sites in the southern (SGS) and the northern (NGS) Guinea savanna. The proportion of N derived from N2-fixation (%Ndfa) was comparable between intercrops and sole crops. However, the amount of N2-fixed was significantly larger in sole crops due to a greater biomass accumulation. Legumes in poorly fertile fields had significantly smaller shoot δ15N enrichment (−2.8 to +0.7‰) and a larger %Ndfa (55–94%) than those in fertile fields (−0.8 to +2.2‰; 23–85%). The N2-fixed however was larger in fertile fields (16–145kgNha−1) than in poorly fertile fields (15–123kgNha−1) due to greater shoot dry matter and N yields. The legumes grown in the NGS obtained more of their N requirements from atmospheric N2-fixation (73–88%) than legumes grown in the SGS (41–69%). The partial soil N balance (inkgha−1) was comparable between intercrops (−14 to 21) and sole legumes (−8 to 23) but smaller than that of sole maize receiving N fertiliser (+7 to +34). With other N inputs (aerial deposition) and outputs (leaching and gaseous losses) unaccounted for, there is uncertainty surrounding the actual amount of soil N balances of the cropping systems, indicating that partial N balances are not reliable indicators of the sustainability of cropping systems. Nevertheless, the systems with legumes seem more attractive due to several non-N benefits. Our results suggest that soybean could be targeted in the SGS and cowpea in the NGS for greater productivity while groundnut is suited to both environments. Grain legumes grown in poorly fertile fields contributed more net N to the soil but growing legumes in fertile fields seems more lucrative due to greater grain and stover yields and non-N benefits.

Maize-grain legume intercropping for enhanced resource use efficiency and crop productivity in the Guinea savanna of northern Ghana

Smallholder farmers in the Guinea savanna practise cereal-legume intercropping to mitigate risks of crop failure in mono-cropping. The productivity of cereal-legume intercrops could be influenced by the spatial arrangement of the intercrops and the soil fertility status. Knowledge on the effect of soil fertility status on intercrop productivity is generally lacking in the Guinea savanna despite the wide variability in soil fertility status in farmers’ fields, and the productivity of within-row spatial arrangement of intercrops relative to the distinct-row systems under on-farm conditions has not been studied in the region. We studied effects of maize-legume spatial intercropping patterns and soil fertility status on resource use efficiency, crop productivity and economic profitability under on-farm conditions in the Guinea savanna. Treatments consisted of maize-legume intercropped within-row, 1 row of maize alternated with one row of legume, 2 rows of maize alternated with 2 rows of legume, a sole maize crop and a sole legume crop. These were assessed in the southern Guinea savanna (SGS) and the northern Guinea savanna (NGS) of northern Ghana for two seasons using three fields differing in soil fertility in each agro-ecological zone. Each treatment received 25kg P and 30kgKha−1 at sowing, while maize received 25kg (intercrop) or 50kg (sole) N ha−1 at 3 and 6 weeks after sowing. The experiment was conducted in a randomised complete block design with each block of treatments replicated four times per fertility level at each site. Better soil conditions and rainfall in the SGS resulted in 48, 38 and 9% more maize, soybean and groundnut grain yield, respectively produced than in the NGS, while 11% more cowpea grain yield was produced in the NGS. Sole crops of maize and legumes produced significantly more grain yield per unit area than the respective intercrops of maize and legumes. Land equivalent ratios (LERs) of all intercrop patterns were greater than unity indicating more efficient and productive use of environmental resources by intercrops. Sole legumes intercepted more radiation than sole maize, while the interception by intercrops was in between that of sole legumes and sole maize. The intercrop however converted the intercepted radiation more efficiently into grain yield than the sole crops. Economic returns were greater for intercrops than for either sole crop. The within-row intercrop pattern was the most productive and lucrative system. Larger grain yields in the SGS and in fertile fields led to greater economic returns. However, intercropping systems in poorly fertile fields and in the NGS recorded greater LERs (1.16–1.81) compared with fertile fields (1.07–1.54) and with the SGS. This suggests that intercropping is more beneficial in less fertile fields and in more marginal environments such as the NGS. Cowpea and groundnut performed better than soybean when intercropped with maize, though the larger absolute grain yields of soybean resulted in larger net benefits.

Maize-bean intercrop response to nutrient application relative to maize sole crop response

Maize-bean intercropping is important in sub-Saharan Africa. Maize sole crop (MSC) nutrient response has been much studied but data is scarce for determination of intercrop functions. A procedure for adapting MSC functions for the maize-bean intercrop was developed. Maize sole crop and intercrop responses were near parallel with notable exceptions for P in high potential areas for maize and for K. Mean intercrop bean yield with no nutrient application was about 0.4 Mg ha−1 and increased on average by 24, 11 and −3% with N, P and K application, respectively. Response function coefficients for MSC adjusted with the ratio of bean to maize grain value as the dependent variable accounted for nearly all variation in intercrop response coefficients providing the basis for determining intercrop response functions from MSC functions. Maize grain yield equivalent was less with MSC compared with intercrop; exceptions were for response to N in high potential areas and for bean to maize value ratios of two or less. The economically optimal rate of N and P were on average about 15% more but less for K with intercrop compared with MSC but with inconsistency. The economically optimal rate ranged widely with variation in the cost of nutrient use relative to grain value but generally without great effect on yield; an exception was a great effect on MSC yield response to N for high potential areas. Intercrop nutrient response functions can be reliably determined once maize sole crop functions are determined for a recommendation domain.