Sole Maize Research Articles

Water and radiation use in maize–pea intercropping is enhanced with increased plant density

AbstractCrop management to improve water use is a well‐established strategy for the effective use of limited natural resources in intercropping systems. Here, maize (Zea mays L.)– pea (Pisum sativum L.) strip intercropping with three maize densities (D1: 45,000, D2: 52,500, and D3: 60,000 plants ha−1) was compared to sole maize with three maize densities and sole pea. Soil water extraction and water difference were determined through soil water content over depth and across rows in intercropping, measured six times during the growing season. Land equivalent ratio (LER), radiation use efficiency (RUEGY for grain yield, and RUEBM for biomass), and water use efficiency (WUE) were calculated to compare intercropping with sole cropping. A soil water supplement potential from intercropped maize strips to intercropped pea was observed during the pea independent growth and co‐growth with maize periods, which declined as the growing season progressed and with increased maize density. After pea harvest, the potential of compensatory soil water for maize existed from the pea strips, which was greater with increased maize density. Maize–pea intercropping produced 23–38% greater total yield than corresponding sole crops, as the LER ranged from 1.23 to 1.38. Maize–pea intercropping with D3 attained the greatest grain yield, RUEGY, RUEBM, and WUE among three maize density treatments, and was 10, 9, 17, and 14% greater than that of corresponding sole maize. Increasing maize density increased grain yield, radiation and water use efficiency, and LER, indicating that the intercropping advantage was improved with increased maize density.

Carbon sequestration and selected hydraulic characteristics under conservation agriculture and traditional tillage practices in Malawi

Conservation agriculture (CA) is increasingly promoted among smallholder farmers of sub-Saharan Africa in a quest to improve food security while sustaining the natural resource base of the agro-ecosystems where agriculture is based. The aim of this study was to investigate the effects of CA and traditional tillage on soil organic carbon (SOC) and selected hydraulic properties in two contrasting agro-ecological zones of Malawi. Six farmers hosted on-farm trials in each location, with each farmer having the following treatments: CA with continuous sole maize (CA-SM), CA with maize–legume intercrops (CA-ML), and traditional tillage with continuous sole maize (CT-SM). Soil samples were randomly collected in October 2015, from farmers’ fields located in Chipeni, Chinguluwe, Lemu, and Zidyana where CA had been implemented for 10 years (2005–2015) at six depth intervals: 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm. Bulk density, soil water characteristics, and pore size distribution were determined using undisturbed core samples. At all sites, CA improved total SOC, carbon stocks, and the stable fraction of particulate organic carbon. Maize–legume intercropping under CA had 35%, 33%, and 73% more total SOC than CT-SM in Chipeni, Lemu, and Zidyana respectively. In Chinguluwe and Lemu, CA-ML had 0.54 and 0.50 g kg–1 respectively more stable fraction of particulate organic carbon (POMP) than CT-SM; whereas in Chipeni, CA-SM had 0.73 g kg–1 higher POMP compared with CT-SM. CA also improved soil porosity, pore size distribution, and water retention capacity by increasing the proportion of mesopores and micropores compared with CT-SM. Thus, changing management practices from CT-SM to CA has the potential to improve the soil organic matter and soil hydraulic properties across agro-ecological zones in Malawi, which is important for sustainable agriculture. Farmers should be encouraged to minimise tillage, retain residues as mulch on the soil surface, and practice crop rotation.

Effect of tillage and maize-cowpea intercrop on fractal features of particle and aggregate size distribution on a tropical sandy loam soil in southwest Nigeria

The effects of tillage and cropping pattern on soil aggregation, fractal dimensions and distribution of organic carbon fractions were studied. Treatments were no- tillage (NT), conventional tillage (CT), and four cropping patterns viz: sole maize, sole cowpea, maize-cowpea intercrops and control (no crop). Soil samples were analysed for particle size distribution (PSD); aggregation ratio (AR), mean- weight diameter (MWD) and aggregated silt+clay (ASC). Mass fractal dimension (Dm) was obtained from PSD; while fragmentation fractal dimension (Df) was obtained from aggregate sizes. Total organic carbon (TOC), free and occluded particulate organic carbon (fPOC and oPOC), were measured. Results showed that structural stability at micro-aggregate scale measured by aggregated silt + clay (ASC) was significantly (p < 0.05) highest for NT (4.07) than CT (1.58). The CT significantly (P ≤ 0.05) reduced the larger aggregate fraction (5.66-2.00 mm). The difference in fractal dimensions was significantly higher with NT than control with CT. Lower difference between Dm and Df with CT represents high- er degree of fragmentation of aggregates. Correlation showed significant positive linear relationships between Dm and sand (p < 0.05, r = 0.627) and negative rela- tionship with silt and clay (r = -0.675). Therefore, fractal dimensions derived from aggregates sizes rather than particle size distribution reflected the impact of land management practices on fragmentation of aggregates of most tropical soils.

Dynamic process-based modelling of crop growth and competitive water extraction in relay strip intercropping: Model development and application to wheat-maize intercropping

Strip intercropping increases land use efficiency but the effect on water use efficiency is less well-known. Here we develop a modelling method to simulate the growth of an intercrop taking into account the acquisition of light and water by the component species in order to calculate the efficacy of light and water acquisition in an intercropping system as compared to sole crops. The model is parameterized, calibrated and validated using data on wheat-maize intercropping in Gansu province, Northwest China. Observed above-ground biomass was 1630 g m−2 for sole wheat and 1334 g m−2 for intercropped wheat while it was 3023 g m−2 for sole maize and 2259 g m−2 for intercropped maize. The average water use was 405 mm in sole wheat, 595 mm in sole maize and 711 mm in wheat-maize intercropping. Based on observed yields, the land equivalent ratio (LER) was 1.59 and the water equivalent ratio (WER) was 1.14, where LER and WER express the relative amounts of land and water needed to achieve the yields obtained in a unit area of intercrop using sole crops. These results indicate that relay strip intercropping of wheat and maize achieves an increase of land use efficiency of 59% and of water use efficiency of 14%. Overall the intercrop model gave satisfactory predictions, with coefficients of efficiency (CE) in validation of 0.86–0.97, 0.90–0.95, 0.85–0.91 and 0.98 for biomass of sole wheat, sole maize, intercropped wheat, and intercropped maize, respectively. Overall CE of water use was 0.95. Simulated LER and WER were similar to observed LER and WER. The results show that intercropping could be used to obtain more yield on less land with less water. Policies that limit water use per unit land and prohibit the use of intercropping on the basis of its high water use per unit area may therefore be counter-productive. The model for intercrop growth and development under water limitation may be used for exploring production possibilities under land and water constraints.

Agro-Economic Performance of Intercropping Hybrid Maize with Vegetables and Spices at Farmer’s Field

The experiment was conducted at Multi Location Testing (MLT) site, Moulvibazar, Bangladesh during rabi season of 2016-17 and 2017-18 to study the profitability of intercropping of hybrid maize with vegetables and spices. Five intercrop combinations of hybrid maize along with sole maize were arranged in randomized complete block design (RCBD) replicated six times. There were six treatments viz., T1: Maize + potato, T2: Maize + red amaranth, T3: Maize + spinach, T4: Maize+ data shak, T5: Maize + coriander and T6: Maize as sole. The grain yield of maize in intercropped combination varied significantly. The highest grain yield (9.71 t ha-1) was in sole maize. The highest maize equivalent yield 15.60 t ha-1 was recorded from the treatment T1 (100% maize + potato) whereas the lowest yield (8.61 t ha-1) was obtained from the treatment T6 (sole maize). The highest gross return (Tk. 312000 ha-1) and benefit cost ratio (3.29) was obtained from the treatment T1 (100% maize + potato). On the contrary, the lowest gross margin (Tk. 101600 ha-1) was obtained from treatment T2 (maize + red amaranth). It revealed that the combination of maize with potato was more compatible and profitable intercropping system in Sylhet region of Bangladesh
 Bangladesh Agron. J. 2018, 21(2): 73-78

Intercropping maize and soybean increases efficiency of land and fertilizer nitrogen use; A meta-analysis

Intercropping exploits species complementarities to achieve sustainable intensification by increasing crop outputs per unit land with reduced anthropogenic inputs. Cereal/legume intercropping is a classical case. We carried out a global meta-analysis to assess land and fertilizer N use efficiency in intercropping of maize and soybean as compared to sole crops, based on 47 studies reported in English and 43 studies reported in Chinese. The data were extracted and analyzed with mixed effects models to assess land equivalent ratio (LER) of intercropping and factors affecting LER. The worldwide average LER of maize/soybean intercropping was 1.32 ± 0.02, indicating a substantial land sparing potential of intercropping over sole crops. This advantage increased as the temporal niche differentiation between the two species was increased by sowing or harvesting one crop earlier than the other as in relay intercropping, i.e. with only partial overlap of the growing periods of the two species The mean fertilizer N equivalent ratio (FNER) was 1.44 ± 0.03, indicating that intercrops received substantially less fertilizer N than sole crops for the same product output. These fertilizer savings are mainly due to the high relative maize yield and the lower N input in the intercrop compared to the input in sole maize. This meta-analysis thus shows that exploiting species complementarities by intercropping maize and soybean enables major increases in land productivity with less fertilizer N use. Both LER and FNER increased as the difference in growth duration increased for maize and soybean, but were not affected by fertilizer N rate. LER increased when soil organic matter increased but FNER did not change with soil organic matter.

Yield and nitrogen uptake of sole and intercropped maize and peanut in response to N fertilizer input

AbstractChinese agriculture needs to become less dependent on fertilizer inputs to enhance sustainability. Cereal/legume intercropping is a potential pathway to lower fertilizer inputs, but there is insufficient knowledge on the nitrogen (N) response in species mixtures. Here, we investigated N response in maize/peanut intercropping. Maize showed a stronger yield response to N input than peanut both in sole cropping and in intercropping, and so did sole crops relative to intercrops. Maize yield was the highest at the maximum level tested: 360 kg N/ha. Agronomic efficiency (AE) of sole maize was 7.8 kg/kg N input, averaged across five N levels (0, 90, 180, 270, and 360 kg/ha). Partial land equivalent ratios (pLERs) for maize decreased with N input, from 0.70 at zero to 0.64 at 360 kg/ha. Sole peanut showed an optimum yield response to N input, with the highest yield at 270 kg/ha and lower yield at 360 kg/ha. The average AE of sole peanut was 1.3 kg/kg. The pLER of peanut declined from 0.43 at zero to 0.32 at 360 kg/ha while the overall LER decreased from 1.13 to 0.96, indicating relative better performance of intercropping at low than at high N input. Apparent recovery (RE) for N was 27.2% for sole maize, 12.4% for sole peanut, and 7.2% for intercrops. Mean N uptake was 179 kg/ha in sole maize, 199 kg/ha in intercropping, and 264 kg/ha in sole peanut. Partial economic budgeting indicated that with the current low Chinese N fertilizer prices, gross margin is maximized with high N input in sole crops; however, for intercropping, the highest gross margin was attained at intermediate N inputs of 180 or 270 kg/ha. Fertilizer price incentives may facilitate a transition to intercropping at moderate N input in China.

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.

Yield, yield attributes and photosynthetic physiological characteristics of dryland wheat (Triticum aestivum L.)/maize (Zea mays L.) strip intercropping

Intercropping has been widely adopted by farmers for higher yield compared to monoculture, and the border effect was responsible for the yield advantage in irrigated areas. However, few studies have investigated the border effect based on photosynthesis, especially under rainfed conditions. Here, we evaluated the yield in rainfed wheat/maize strip relay intercropping, and explored the associated differences in yield components and physiological process compared to sole crops. A two-year field experiments was conducted including three treatments (sole wheat, sole maize and wheat/maize intercropping) in Yangling, located in the semi-humid region of northwest China. Grain yield, yield components, chlorophyll relative content (SPAD) and photosynthetic parameters in different rows were measured for wheat and maize. Results showed that wheat/maize intercropping increased the land use efficiency and total yield of wheat and maize under rainfed conditions. The yield of intercropped wheat was significantly (p < 0.05) increased by 35% on average over two years, resulting not only from the first border rows but also from the second border rows. The yield improvement in the first border rows relative to sole wheat was attributed to the increase of ear number (56%, p < 0.05), kernel number per ear (14%, p < 0.05) and thousand kernel weight (12%, p < 0.05), but the yield improvement in the second border rows was only attributed to the ear number (22%, p < 0.05). The yield of intercropped maize was not significantly (p > 0.05) decreased (6%), mainly attributed to the border rows (19% lower than in sole maize), in which the kernel number per cob and thousand kernel weight were 14% and 8% (p < 0.05) lower than that in sole maize. This was because that the SPAD and photosynthetic rate of maize in intercropping was suppressed during the co-growth period (about 62 days). Although the two had a partly growth recovery after wheat harvest, the growth recovery was not complete, and this was responsible for the reduction of maize yield in intercropping. This study demonstrates that the importance of yield components and the photosynthesis basis for yield advantage in intercropping systems, and reducing the adverse effect of dominate crop on subordinate crops could better exert the advantages of intercropping.

Effects of Residual Organic Manure and Supplemental Inorganic Fertilizers on Performance of Subsequent Maize Crop and Soil Chemical Properties

Field experiments were conducted during 2014 and 2015 to evaluate the effects of residual organic fertilizers with supplemental inorganic fertilizers on performance of subsequent maize crop and soil chemical properties at Field 2, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia. In the first season, the trial was conducted by using 4 nutrient management treatment (control, 100% poultry manure (PM), 100% NPK and 50% NPK + 50% PM) in 3 cropping system (sole maize, sole soybean and maize + soybean intercropping). The following trial was conducted by using the first experimental plot. After harvest of the crops in the first experiment, the biomass was left and incorporated manually into the soil before planting the subsequent maize crop. The experiment comprised of 14 treatments, 12 based on the first experiment and two additional treatments for comparison (control and 100% NPK). The treatments were laid down in a randomized complete block design (RCBD) with three replications. The results showed that all fertilizer treatments increased growth, yield and yield components of the subsequent maize crop. However, incorporation of maize residue alone was ineffective in increasing yield of the subsequent maize crop. The combination of crop residue with residual PM enhanced soil pH, organic matter and nutrient availability in the soil. The combined application of soybean residue + 50% residual PM + 50% phosphorous and potassium (PK) fertilizer and soybean residue + 100% PK gave maize yield same level as 100% NPK. Therefore, it can be recommended that substitution of 50% inorganic fertilizer with residual PM and substitution of N fertilizer in soybean residue is recommended to increase yield of maize and improve soil chemical properties. Keywords: crop residue, NPK fertilizer, poultry manure, residue, yield DOI : 10.7176/JNSR/9-22-05 Publication date: November 30 th 2019

Maize/peanut intercropping increases photosynthetic characteristics, 13C-photosynthate distribution, and grain yield of summer maize

Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in Shandong, China. Treatments included sole maize (SM), sole peanut (SP), and an intercrop consisting of four rows of maize and six rows of peanut (IM and IP). The results showed that the intercropping system had yield advantages based on the land equivalent ratio (LER) values of 1.15 and 1.16 in the two years, respectively. Averaged over the two years, the yield of maize in the intercropping was increased by 61.05% compared to that in SM, while the pod yield of peanut was decreased by 31.80% compared to SP. Maize was the superior competitor when intercropped with peanut, and its productivity dominated the yield of the intercropping system in our study. The increased yield was due to a higher kernel number per ear (KNE). Intercropping increased the light transmission ratio (LTR) of the ear layer in the maize canopy, the active photosynthetic duration (APD), and the harvest index (HI) compared to SM. In addition, intercropping promoted the ratio of dry matter accumulation after silking and the distribution of 13C-photosynthates to grain compared to SM. In conclusion, maize/peanut intercropping demonstrated the potential to improve the light condition of maize, achieving enhanced photosynthetic characteristics that improved female spike differentiation, reduced barrenness, and increased KNE. Moreover, dry matter accumulation and 13C-photosynthates distribution to grain of intercropped maize were improved, and a higher grain yield was ultimately obtained.

A new pest, Spodoptera frugiperda (J.E. Smith), in tropical Africa: Its seasonal dynamics and damage in maize fields in northern Ghana

Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), was first detected in Africa in 2016. Efforts at controlling it have been challenged by the many unknowns about this invasive insect. The population dynamics of FAW moths and the damage caused by the larvae were studied in maize fields over two successive seasons in northern Ghana. Pheromone traps were deployed in sole maize fields located in Northern (NR), Upper East (UER) and Upper West (UWR) regions to assess male moth population over time. Data on damage to maize by the larvae as well as climatic variables were also recorded. A total of 2601 FAW moths were captured over the two seasons from the three regions. In general, catches increased steadily from time of emergence (i.e., 12.2 ± 1.4 and 14.4 ± 2.6 moths in July 2017 and 2018, respectively) and peaked when the plants were growing into the reproductive stage (i.e., 13.9 ± 2.2 and 56.0 ± 14.9 moths in August 2017 and 2018, respectively); afterwards catches declined significantly. There were no significant differences between regions in both years for mean their moth catches. Damage to maize was significantly higher in 2017 (4.8 ± 0.4) than in 2018 (2.4 ± 0.3) (P = 0.005). This variable correlated positively with FAW larval abundance. Rainfall was the only climatic variable that influenced moth abundance significantly and positively in all three regions in both years; except for 2018 in UER. Thus, management of FAW in northern Ghana and locations with similar agro-ecologies must be from emergence to the tasselling stage, as well as periods of increased precipitation.

Soil and nutrients losses under different crop covers in vertisols of Central India

PURPOSE: Accelerated erosion removes fertile top soil along with nutrients through runoff and sediments, eventually affecting crop productivity and land degradation. However, scanty information is available on soil and nutrient losses under different crop covers in a vertisol of Central India. Thus, a field experiment was conducted for 4 years (2010–2013) to study the effect of different crop cover combinations on soil and nutrient losses through runoff in a vertisol. MATERIALS AND METHODS: Very limited information is available on runoff, soil, and nutrient losses under different vegetative covers in a rainfed vertisol. Thus, the hypothesis of the study was to evaluate if different crop cover combinations would have greater impact on reducing soil and nutrient losses compared to control plots in a vertisol. This experiment consisted of seven treatment combinations of crop covers namely soybean (Glycine max) (CC₁), maize (Zea mays) (CC₂), pigeon pea (Cajanus cajan) (CC₃), soybean (Glycine max) + maize (Zea mays) − 1:1 (CC₄), soybean (Glycine ma x)) + pigeon pea (Cajanus cajan) −2:1 (CC₅), maize (Zea mays) + pigeon pea (Cajanus cajan) − 1:1 (CC₆), and cultivated fallow (CC₇). The plot size was 10 × 5 m with 1% slope, and runoff and soil loss were measured using multi-slot devisor. All treatments were arranged in a randomized block design with three replications. RESULTS AND DISCUSSION: Results demonstrated that the runoff and soil loss were significantly (p < 0.05) higher (289 mm and 3.92 Mg ha⁻¹) under cultivated fallow than those in cropped plots. Among various crop covers, sole pigeon pea (CC₃) recorded significantly higher runoff and soil loss (257 mm and 3.16 Mg ha⁻¹) followed by that under sole maize (CC₂) (235 mm and 2.85 Mg ha⁻¹) and the intercrops were in the order of maize + pigeon pea (211 mm and 2.47 Mg ha⁻¹) followed by soybean + maize (202 mm and 2.38 Mg ha⁻¹), and soybean + pigeon pea (195 mm and 2.15 Mg ha⁻¹). The lowest runoff and soil loss were recorded under soybean sole crop (194 mm and 2.27 Mg ha⁻¹). The data on nutrient losses indicated that the highest losses of soil organic carbon (SOC) (25.83 kg ha⁻¹), total nitrogen (N), phosphorus (P), and potassium (K) (7.76, 0.96, 32.5 kg ha⁻¹) were recorded in cultivated fallow (CC₇) as compared to those from sole and intercrop treatments. However, sole soybean and its intercrops recorded the minimum losses of SOC and total N, P, and K, whereas the maximum losses of nutrients were recorded under pigeon pea (CC₃). The system productivity in terms of soybean grain equivalent yield (SGEY) was higher (p < 0.05) from maize + pigeon pea (3358 kg ha⁻¹) followed by that for soybean + pigeon pea (2191 kg ha⁻¹) as compared to sole soybean. Therefore, maize + pigeon pea (1:1) intercropping is the promising option in reducing runoff, soil-nutrient losses, and enhancing crop productivity in the hot sub-humid eco-region. CONCLUSIONS: Study results highlight the need for maintenance of suitable vegetative cover as of great significance to diffusing the erosive energy of heavy rains and also safe guarding the soil resource from degradation by water erosion in vertisols.

Effects of conservation agriculture on productivity and Economics of maize-wheat based cropping systems in midwestern Nepal

The effects of two tillage methods (zero tillage and conventional tillage), two residue managements (residue kept and residue removed) and two levels of cropping system (maize + soybean and sole maize) were studied over 3 years (2015-2017) at Dailekh district of Nepal. Arun-2 and Puja were the varieties of maize and soybean used respectively, followed by winter wheat. The results revealed that the maize + soybean system had significantly higher plant population and ear population (34.83 thousands ha-1 and 34.35 thousands ha-1, respectively), grains per row (37.1), ear length (16.6 cm) and 20.5% higher grain yield as compared to sole maize. The highest maize equivalent yield (7.92 t ha-1) was recorded in maize + soybean as compared to the lower grain yield equivalent (7.06 t ha-1) in sole maize. Zero tillage accounted relatively higher benefits (high net income and B:C ratio) as compared to conventional tillage. The residue kept plot resulted significantly higher B:C ratio (2.41) than the residue removed (2.11) and the maize + soybean recorded 82.5% greater B:C ratio compared to sole maize. Net annual income was significantly higher in zero tillage, residue kept and maize + soybean system (NRs. 223072.00, 222958.00 and 269016.00 ha-1 respectively). Such combinations are recommended for Dailekh district of Nepal to have profitable crop productivity.&#x0D; SAARC J. Agri., 17(1): 49-63 (2019)

Effect of intercropping on maize grain yield and yield components

Smallholders in developing countries commonly use intercropping to produce crops with higher yield and value. Many intercropping studies have been conducted under experimental conditions, but few studies have been performed in farmers' fields. We conducted a 4-year study using data from real farms to examine the relationships between yield and yield components of intercropped maize in the North China Plain. Three field experiments were conducted to compare the suitability of different maize varieties in intercropping. In the farm study, the grain yield of maize intercropped with watermelon was reduced by more than one third as compared to maize in wheat-maize double cropping, mainly due to lower ear density and lower 100-grain weight. Under real farm conditions, the yield of intercropped maize increased with increasing ear density and 100-grain weight, while yield of sole maize increased with increasing grain number per ear and 100-grain weight. In the field experiments, the maize cultivars commonly used in double cropping gave similar yields when grown in the intercropping system and their yields were closely related to ear density and 100-grain weight. Our results demonstrated that ear density, rather cultivar, was a key factor affecting the productivity of intercropped maize. Therefore, maintaining high ear density is a practical way for promoting productivity of maize in farmers' intercropping practices.

GROWTH AND YIELD RESPONSE OF NEWLY RELEASED CASSAVA GENOTYPES AND HYBRID MAIZE TO INTERCROPPING

Cassava/maize intercrops have been reported to be highly productive, mainly because of their different growth patterns. However, there is limited information on the influence of maize planting density in the cassava/maize intercrop on the performance of hybrid maize and improved cassava genotypes in Uganda. Thus, this study determined whether recently released cassava genotypes which are selected on the basis of monocrop performance, would perform equally well when intercropped with hybrid maize varieties. Cassava genotypes NAROCASS 1 and NASE 14 intercropped with Longe 6H maize were evaluated using randomized complete block design and three replications. Treatments were: Sole maize (SM), sole cassava (SC), alternate rows of cassava and maize (1C:1M), and one row of cassava alternating with two rows of maize (1C:2M). Intercropping significantly increased the maize plant heights in the 1C:2M system than in sole maize. Cob length and number of rows per cob decreased as the plant population density increased. Maize grain yield under the 1C:1M system was comparable to that of sole cropping. The 1C:2M system gave significantly reduced grain yields when compared with those at 1C:1M. Cassava root yield decreased in the order (SM&gt;1C:1M&gt;1C:2M). Although the yields of both cassava and maize under sole cropping were higher than their intercrop counterparts, intercropping was more productive than sole cropping as evidenced by the land equivalent ratios.

Soil moisture management and fertilizer micro-dosing on yield and land utilization efficiency of inter-cropping maize-pigeon-pea in sub humid Tanzania

Principally caused by soil water stress and declining soil fertility, low crop productivity results in both food and income insecurity. The effects of nitrogen and phosphorus fertilizer micro-dosing with inter-row rainwater harvesting practices for maize and pigeon-pea inter-cropping on yield and land use efficiency are inadequately documented in sub humid tropics. A field experiment on sandy loam soils in sub humid conditions using a split-split plot design was conducted. Plots used in situ rainwater harvesting practices of tied ridges, open ridges, and flat cultivation. Sub-plots were sole maize, sole pigeon-pea, and 1:1 maize-pigeon pea inter-cropping. The sub-sub plots were control, fertilizer (N and P) application at the micro-dose level, and recommended rates. Tied ridges significantly (p < 0.001) conserved more soil moisture than flat cultivation at 30 cm depth after ten days of rainfall. Ridges increased maize yield by 0.3 t ha−1 over flat cultivation. Fertilizer application significantly (p < 0.001) increased maize yield by 1.12 t ha−1 with micro-dosing and by 1.60 t ha−1 with recommended rates over the control. Combining tied ridges and fertilizer significantly (p < 0.040) increased maize yield by 132–156% compared to flat cultivation without fertilizer. Reflecting a land equivalent ratio, land use efficiency was 67–122% higher in inter-cropping than sole crop. Tied ridges conserved more soil moisture than flat cultivation, enhancing fertilizer use efficiency that improved crop yields and land equivalent ratio under inter-cropping. This strategy could increase food availability and income generation under smallholder farming systems in sub-humid tropic areas.

Synchrony of nitrogen supply and crop demand are driven via high maize density in maize/pea strip intercropping

Cereal density may influence the balance between nitrogen (N) supply and crop N demand in cereal/legume intercrop systems. The effect of maize (Zea mays L.) plant density on N utilization and N fertilizer supply in maize/pea (Pisum sativum L.) strip intercropping was evaluated in a field study with sole maize, sole pea, and intercropped maize/pea with three maize densities (D1, 45,000 plants ha−1; D2, 52,500 plants ha−1; D3, 60,000 plants ha−1) and two N treatments (N0, 0 kg N ha−1; N1, 450 kg N ha−1 for maize and 225 kg N ha−1 for pea). Soil mineral N in intercropped strips decreased with increased maize density. Increased maize density decreased N accumulation for intercropped pea but increased it for maize and the sum of both intercrops. The land equivalent ratio for grain yield (LER grain) showed a 24–30% advantage for intercrops than corresponding sole crops, and was greater with D3 than D1 and D2. Maize/pea intercropping had 4–113% greater nitrogen use efficiency (NUE) than sole maize, which was enhanced with increased maize density. Increasing maize density improved the synchrony of N supply and crop demand in maize/pea strip intercropping.

Determination of Optimum Crop Mix Using Linear (LP) Programming among Small Holder Farmers in Agricultural Zone Four of Adamawa State, Nigeria

Linear programming was applied to farm data collected from 120 smallholder farmers in 2017/18 cropping season in agricultural zone four (4) of Adamawa state, Nigeria for the purpose of identifying optimal crop mix to maximize revenue. A total of twenty (20) cropping enterprises were identified in the existing cropping pattern, fifteen (15) mixed and five (5) sole cropping enterprises. Popular enterprises identified included four mixed and two sole cropping enterprises and all the six enterprises showed positive net return. The result of the linear programming analysis however, showed that the optimal farm plan at observed maximum resource levels admitted only groundnut and sorghum in the final plan to be produced at 2 hectares with an associated total gross margin of N478, 380.00. In the sensitivity analysis identified with the observed maximum resource level, land was the only binding resource in the final plan. The optimal farm plan at observed average resource levels showed that three enterprises; groundnut/sorghum, maize/sorghum and sole maize were admitted in the final plan under 0.45ha, 0.21ha and 0.17ha, respectively. The associated total gross margin was N153, 003.99. In the sensitivity analysis associated with the observed average resources, only NPK, SSP, Laraforce were binding resources. The study recommended that the optimum enterprises and resources combination obtained in the Linear Programming output should be extended to the farmers to enhance their profit level, beside; farmers should be encouraged through adequate support and promotions to improve the production techniques of these recommended enterprises.

Growth and development of soybean under changing light environments in relay intercropping system

BackgroundMaize-soybean relay-intercropping (MSR) is a famous system of crop production in developing countries. However, maize shading under this system directly affects the light quality and intensity of soybean canopy. This is a challenging scenario in which to implement the MSR system, in terms of varieties selection, planting pattern, and crop management since the duration of crop resource utilization clearly differs.MethodsTherefore, this experiment aimed to elucidate the effect of leaf excising treatments from maize top to fully clarify the needs and balance of light quality and intensity of intercrop-soybean under MSR in field conditions. The effects of different leaf excising treatments (T0, no removal of leaves; T2, removal of two topmost leaves; T4, removal of four topmost leaves; T6, removal of six topmost leaves from maize plants were applied at first-trifoliate stage (V1) of soybean) on photosynthetically active radiation transmittance (PART), red to far-red ratio (R:FR), morphological and photosynthetic characteristics and total biomass production at second-trifoliate stage (V2), fifth-trifoliate stage (V5), and flowering-stage (R1) of soybean were investigated through field experiments for 2-years under MSR.ResultsAs compared to T0, treatment T6 increased the PART and R:FR ratio at soybean canopy by 77% and 37% (V2), 70% and 34% (V5), and 41% and 36% (R1), respectively. This improved light environment in T6 considerably enhanced the leaf area index, SPAD values and photosynthetic rate of soybean plants by 66%, 25% and 49% at R1, respectively than T0. Similarly, relative to control, T6 also increased the stem diameter (by 29%) but decreased the plant height (by 23%) which in turn significantly increased stem breaking strength (by 87%) by reducing the lodging rate (by 59%) of soybean plants. Overall, under T6, relay-cropped soybean produced 78% of sole soybean seed-yield, and relay-cropped maize produced 81% of sole maize seed-yield. Our findings implied that by maintaining the optimum level of PART (from 60% to 80%) and R:FR ratio (0.9 to 1.1), we can improve morphological and photosynthetic characteristics of soybean plants in MSR. Therefore, more attention should be paid to the light environment when considering the sustainability of MSR via appropriate planting pattern selection.