Enhancing yield and economic returns through interspecific interactions in a wheat–leafy vegetable intercropping system

The present study was undertaken to find out appropriate model using seven contemporary model selection criteria that could best describe the growth pattern of wheat production in Bangladesh and its three major areas like Dmajpur, Rajshahi, and Rangpur districts during the time periods 1971-72 to 2004-05. It appeared from the study that the best fitted model for wheat production in Bangladesh, Dinajpur, Rajshahi, and Rangpur were quadratic, linear, and cubic model. It means that the assumption of constant annual rate of growth in percent that lies behind the use of exponential/compound model which is very common in describing growth pattern was not true for the growth pattern of wheat production in Bangladesh. In Dinajpur District, linear model seemed to be appropriate. Five-years’ forecasts of wheat production in Bangladesh, Dinajpur, Rajshahi, and Rangpur districts in the year 2005/06 were 1.55, 0.31, 0.24, and 0.37 million tons, respectively, with a 95 percent confidence interval. The analysis found that if the present growth rates continue then the wheat production in Bangladesh, and Dinajpur, Rajshahi, and Rangpur districts would be 1.54, 0.35, 0.31, and 0.59 million tons, respectively, in the year 2009/10. Keywords: Forecasting; wheat production in Bangladesh. DOI: 10.3329/bjar.v35i1.5863Bangladesh J. Agril. Res. 35(1) : 17-28, March 2010

By using natural resources and agricultural inputs more effectively, intercropping is a desirable technique to boost crop output and economic return. The present study was conducted to figure out the most lucrative crop mix for an intercropping system of cauliflower with red amaranth and radish leafy vegetable. A randomized complete block design with three replications was used to set up the experiment. Treatments included nine different cropping systems, including sole cauliflower, sole red amaranth, sole radish leafy vegetable, cauliflower-red amaranth intercropping (1:1), cauliflower-leafy radish intercropping (1:1), cauliflower-red amaranth-leafy radish intercropping (1:1:1), cauliflower-red amaranth-leafy radish intercropping (2:1:1), cauliflower-red amaranth-leafy radish intercropping (1:2:1) and cauliflower-red amaranth-leafy radish intercropping (1:1:2) Productivity parameters of three intercrops (cauliflower-red amaranth-leafy radish) were collected and measured based on their yield and yield contributing traits in different stages of their growth upto the final harvest. And equivalent yield and land ratio along with benefit cost ratio were analyzed to check their profitability. Result illustrated that cauliflower, red amaranth and leafy radish produced the highest yield of 25.4, 13.5 and 18.6 tha-1, respectively when cultivated as a sole crop. However, when all of the three vegetables were grown as intercropping in different cropping system, cauliflower with red amaranth and leafy radish (1:1:1) produced the highest yield (33.2 tha-1) followed by cauliflower-red amaranth-radish intercropping (1:2:1) and cauliflower-red amaranth-radish intercropping (2:1:1) with the yield of 30.0 t ha-1 and 29.8 tha-1. After assessing the productivity and economic return, cauliflower with red amaranth and leafy radish (1:1:1) obtained the highest gross return (997102 Tk ha-1) and net return (512102 Tk ha-1) using the highest land equivalent ratio (2.0) followed by 900900 Tk ha-1 and 435900 Tk ha-1, respectively in the cropping system cauliflower-red amaranth-radish intercropping (1:2:1). The present study concluded that intercropping leafy vegetables (red amaranth and leafy radish) and cauliflower boosted overall productivity and economic return more than sole intercropping cauliflower.

High water requirement of flood irrigated boro rice is of great concern because water is becoming scarce and expensive day by day. Dry direct seeded boro rice, grown in unpuddled and unsaturated/aerobic soil condition, requires only 50-60% water as compared to traditional flooded transplanted rice, and therefore it could be adopted as a water saving rice cultivation system in boro season of Bangladesh. Moreover, it offers a unique opportunity to grow winter leafy vegetables as intercrop. But high weed infestation is one of the major constraints in dry direct seeded boro rice. Therefore, an experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, during the period from February to June 2017 to study the feasibility of growing different leafy vegetables as intercrop in dry direct seeded boro rice for higher profitability and better weed suppression following a randomized complete block design with three replications. Four leafy vegetables viz., Jute, Gima kalmi, Indian spinach and Red amaranth were intercropped with dry direct seeded boro rice (cv. BRRI dhan28) following three different rice planting patterns such as 50 cm spaced 2 row rice strip, 75 cm spaced 4 row rice strip and 100 cm spaced 5 row rice strip; sole rice was also maintained as control. The highest weed density and dry matter were found in Indian spinach intercropping with 50 cm spaced 2 row rice strip which was statistically identical with sole rice and some other intercropping systems. Performance of Red amaranth as intercrop was the best in terms of weed suppression followed by Jute. Rice yield was the highest (3.8 t ha-1) in sole cropping, and intercropping resulted in significant yield reduction. Although intercropping diminished rice yield, but increased net return and benefit cost ratio (BCR) as compared to rice sole cropping (net return 49910 Tk ha-1 and BCR 1.58). Among the vegetables, Gima kalmi performed the best followed by Red amaranth in terms of yield. Red amaranth intercropping following 50 cm spaced 2 row rice strip resulted in highest weed suppression (32% less weed biomass compared to sole rice) while Gima kalmi intercropping following 50 cm spaced 2 row rice strip showed the highest net return (220340 Tk ha-1) and BCR (3.30). [Fundam Appl Agric 2018; 3(3.000): 545-558]

Simulating potential growth in a relay-strip intercropping system: Model description, calibration and testing

An experiment was conducted during rabi and kharif season of 2018 - 2019 and 2019-2020, respectively at Regional Agricultural Research Station (RARS), Cumilla to find out the suitable crop combination of leafy vegetables with brinjal for increasing productivity and economic return through intercropping system. Five treatments viz. Brinjal + Red amaranth (T1), Brinjal + Leaf amaranth (T2), Brinjal + Patshak (T3), Brinjal + Spinach (T4) and Sole crop of brinjal (T5) were used in rabi season. In kharif season all the treatments were same except T4 where Indian spinach was used with brinjal instead of spinach. Results showed that yield and yield contributing characters of brinjal did not differ significantly due to different intercropping systems. Yield of brinjal was comparatively low in intercropping but total productivity increased due to additional yield of leafy vegetables. Increase of total productivity in terms of brinjal equivalent yield (BEY) was 2.03 to 25.68% (Rabi) and 2.36 to 22.29% (Kharif) and in intercrop combination compared to sole crop. All the intercropping combinations showed higher brinjal equivalent yield (BEY), gross return and benefit cost ratio (BCR) over sole crop. Among the intercropping combinations, Brinjal + Spinach (rabi) and Brinjal + Indian spinach (kharif-1) was the most feasible and profitable in respect of BEY (48.94 and 27.62 t/ha, respectively), gross return (Tk. 1223400 and 1105000/ha, respectively), gross margin (Tk.908823 and 782487/ha, respectively) and benefit cost ratio (3.88 and 3.42, respectively). Bangladesh J. Agril. Res. 46(1): 89-97, March 2021

A field experiment on intercropping of okra and leafy vegetables was conducted at Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur and Agricultural Research Station, Burirhat, Rangpur during Kharif-I season of 2010 and 2011 to find out suitable crop combination for higher productivity and economic return. Seven treatments viz., sole okra (50 cm × 40cm), okra 100% (in row) + red-amaranth 100% (broadcast), okra 100% (in row) + red-amaranth 75% (broadcast), okra 100% (in row) + leaf amaranth 100% (broadcast), okra 100% (in row) + leaf amaranth 75% (broadcast), okra 100% (in row) + jute as patshak 100% (broadcast), okra 100% (in row) + jute as patshak 75% (broadcast) were used. Intercropping reduced okra yield but total productivity increased due to additional yield of vegetables. In both the locations, sole okra produced the highest yields (15.82 t/ha at Joydebpur and 13.79 t/ha at Burirhat). Among the intercropping treatments, the highest okra yields (15.42 t/ha at Joydebpur and 12.64 t/ha at Burirhat) were obtained from okra 100%+ red amaranth 75% combination. The lowest okra yield (13.16 t/ha at Joydebpur and 11.75 t/ha at Burirhat) was recorded in okra 100% + jute as patshak 100% combination. The highest okra equivalent yield (23.00 t/ha) was recorded in okra 100% + red amaranth 100% at Joydebpur and in okra 100% + leaf amaranth 100% (21.79 t/ha) at Burirhat. These treatment combinations also gave the highest gross margin (Tk. 227180/ha at Joydebpur and Tk. 214600/ha at Burirhat) and benefit cost ratio (5.66 at Joydebpur and 5.58 at Burirhat). The results revealed that cent percent red amaranth (broadcast) or leaf amaranth intercropped with cent percent okra might be suitable combination for higher productivity and economic return at Joydebpur and Burirhat, respectively. Bangladesh J. Agril. Res. 38(1): 137-143, March 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i1.15199

After rice, wheat is the another most imperative source of staple foods in Bangladesh. Wheat production plays a crucial role in ensuring food security. However, persistent inconsistencies between wheat production and cultivated area pose challenges to national food security. This study investigates the trends, variability, and forecasting of wheat production in Bangladesh from 1971 to 2023. Secondary data were collected from the Bangladesh Bureau of Statistics and the Department of Agricultural Extension. The entire period was divided into two periods: 1971–2000 and 2001–2023. A semi-log model was used to estimate the growth rate, while a linear regression model examined the dependency of wheat production on cultivated area. The coefficient of variation (CV) was applied to assess variability, and the Autoregressive Integrated Moving Average (ARIMA) model was employed for forecasting wheat production. A steady decline in the area of wheat cultivation and fluctuations in wheat production was visible throughout the study period. A moderate positive correlation between area and production was observed, which indicates that area under cultivation has an influence on production of wheat in Bangladesh. While the growth rate was unstable throughout the study period with significant variability. The underlying patterns in wheat production was successfully identified by the ARIMA (1,1,0) model providing meaningful forecasts. This paper forecast the wheat production for upcoming 5 years. A consistent trend was detected emphasizing key stages of increase and decrease of wheat production in Bangladesh. To wrap up, though wheat production in Bangladesh has made some improvement, the country deals with a continuous struggle to meet the demand. Strategies to ensure more stable and increased wheat production must be prioritized by the policymakers. Ann. Bangladesh Agric. 29(1): 51-67

برای ارزیابی اثر کشت مخلوط افزایشی ذرت (Zea mays L.) و لوبیا چشم بلبلی (Vigna Sinensis L.) بر وزن خشک و ترکیب گونه ای علف های هرز، یک آزمایش مزرعه ای در شمال خوزستان در سال زراعی 93-1392 انجام گرفت. آزمایش در قالب طرح پایه بلوک های کامل تصادفی در سه تکرار پیاده شد به طوری که ذرت و لوبیا چشم بلبلی در دو تیمار کشت خالص و چهار تیمار کشت مخلوط شامل شامل T1: 100 درصد تراکم کشت خالص ذرت+ 25 درصد کشت خالص لوبیا چشم‌بلبلی، T2: 100 درصد تراکم کشت خالص ذرت+ 50 درصد کشت خالص لوبیا چشم‌بلبلی، T3: 100 درصد تراکم کشت خالص ذرت+ 75 درصد تراکم کشت خالص لوبیا چشم‌بلبلی و T4: 100 درصد تراکم کشت خالص ذرت+ 100 درصد کشت خالص لوبیا چشم‌بلبلی کشت شدند. نتایج آزمایش نشان داد که شاخص مجموع عملکرد نسبی در کلیه تیمارهای کشت مخلوط بیشتر از یک بود که‌این امر حاکی از رابطه مکملی ذرت و لوبیا چشم‌بلبلی در مصرف منابع محیطی از جمله نور و رطوبت می باشد. به عبارت دیگر کاهش منابع محیطی در دسترس، وزن خشک علف های هرز را در سیستم های کشت مخلوط کاهش داد به طوری که از پنج گونه علف‌هرز ثبت شده در طول آزمایش، وزن خشک چهار گونه شامل تاج خروس (Amaranthus retroflexus L.) ، سوروف (Echinochloa cruss-gali L.)، خرفه (Portulaca oleraceae L.) و تاجریزی (Solanum nigrum L.) در کشت مخلوط در مقایسه با کشت خالص ذرت و لوبیا چشم‌بلبلی کاهش یافت. شاخص کارآیی خفه کنندگی علف های هرز نشان داد که در کشت های مخلوط نسبت به کشت خالص ذرت 36-21 درصد و نسبت به کشت خالص لوبیا چشم بلبلی 42-28 از وزن علف های هرز کاسته شد که نشان می‌دهد کشت مخلوط ذرت و لوبیا چشم‌بلبلی باعث کاهش رشد علف‌های هرز در مقایسه با کشت خالص می‌شود.

Water use and yield of wheat/maize intercropping under alternate irrigation in the oasis field of northwest China

Wheat/maize intercropping has been widely practiced in northwestern China. It is crucial to optimize the canopy structure and geometric configurations to enhance the performance of the system. This research determined the responses of intercrops to the different canopy structures created by the different wheat/maize intercropping systems. Field experiments were carried out in 2012, 2013, and 2014 at Wuwei, Gansu. Three intercropping patterns—six rows of wheat alternated with two rows of maize (6W2M), six rows of wheat alternated with three rows of maize (6W3M), and six rows of wheat alternated with four rows of maize (6W4M)—were compared with sole wheat and sole maize. The results showed that maize plant heights differed between the inner rows and the border rows, and the difference was greater for the 6W3M system than for the 6W4M system. The three intercropping systems had an average land-use equivalent ratio (LER, calculated based on grain yield) of 1.25, indicating an increase in land-use efficiency by 25% compared to the corresponding sole crops. The shape of maize strips in 6W3M optimized the canopy structure and increased the productivity of wheat and maize. The wheat in 6W3M had significantly more grain yield compared with the sole wheat and the 6W2M due to the maize belt shape, which resulted in the soil evaporation negatively affecting the intercropped wheat grain yield of the 6W3M. Similarly, the maize belt shape facilitated the light penetration and enhanced the reproductive growth by increasing the two cobs per plant rate (TCR) of the maize. The highest TCR of the 6W3M produced a higher maize grain yield than the 6W2M and sole maize in the three growing seasons. The maize belt width in the strip intercropping system had a significant effect on the grain yield of both wheat and maize, which reduced water evaporation, harmonized light distribution, and increased productivity.

Economic assessment of maize (Zea mays L.) – Spinach (Basella alba L.) intercropping system for improving the livelihood of smallholders’ in South-Asia

Intercropping Persian walnut (Juglans regia L.) and wheat (Triticum aestivum Linn.) in northwest China is receiving increasing attention because it offers potential advantages for improving land-use efficiency, increasing economic returns to farmers and increased sustainability in crop production. We carried out a two-year field intercropping experiment, using a system composed of young Persian walnut trees with wheat to determine the root competitive interactions between the two species, aboveground biomass and the economic yield of each component of the intercropping system at a spacing of 4 × 6 m in Hetian old oasis, south Xinjiang province, northwest China. Roots were sampled by auger in the Persian walnut tree/wheat intercropping system and in the sole wheat and sole walnut systems, down to a depth of 1 m in the soil profile. The results show that the roots of the trees spread under the crop and that the roots of intercropped wheat tended to have a shallower distribution in the soil profile. The roots of both intercropped walnut and wheat had a lower root length density and root diameter and a higher specific root length at all soil depths than those of sole walnut trees and wheat in 2012. Although root competition belowground led to decreases in yield and biomass of both crops, intercropping of Persian walnut and wheat improved the utilization of plant growth resources (LER > 1) as compared with sole crops. Tree height, diameter at breast height and mean radius of crown of intercropped trees in both intercropping years had lower values when compared with the monoculture. We conclude that interspecific interactions occurred largely as below-ground competition between the species investigated. Competition for soil resources was the primary limiting factor for wheat productivity. Further research is needed to examine the dynamic processes of species interactions in intercropping systems with trees of increasing age.

The jujube tree (Zizyphus jujuba Mill.)/wheat (Triticum aestivum L.) agroforestry system is frequently used in China’s Xinjiang Province. The system improves land-use efficiency and increases economic returns. A field experiment was conducted at the Hetian oasis in southern Xinjiang Province to investigate the relationship between root distribution and interspecific interaction between the two intercropped species. The study included seven treatments: sole-cropped 5, 7, or 9-year-old jujube trees (treatments 1–3); 5, 7, or 9-year-old jujube trees intercropped with wheat (treatments 4–6); and sole-cropped wheat (treatment 7). To determine vertical root distribution, soil cores were collected in 20-cm increments from the 0 to 100-cm soil depth. The cores were collected at horizontal distances of 30, 60, 90, 120, and 150 cm from the jujube rows. The results showed that the land equivalent ratios were >1 for the three jujube/wheat intercropping systems. This indicated that these systems were advantageous compared with sole cropping. Tree height, breast height diameter, and mean crown radius were less in the intercropped treatments than in the corresponding sole-cropped treatments. Intercropping reduced the root length densities (RLDs) and root diameters (RDs) of both jujube and wheat at all soil depths. The RLD and RD of 9-year-old jujube trees were greater than those of the 5- and 7-year-old trees, which indicated that the root systems of the 9-year-old trees were more developed. Wheat root growth was inhibited more by older jujube trees than by younger ones. In conclusion, jujube tree/wheat intercropping can be practical and beneficial in the region. However, the mechanisms involved in the belowground interspecific interactions are still unknown. Additional research is needed to provide optimal management strategies and technologies for jujube/wheat intercropping.

Intercropping of legumes in cereals and manuring are important measures to sustain soil fertility and enhance crop productivity in general and under organic and limited moisture conditions in particular. This study evaluated different wheat (Triticum aestivum L.) + chickpea (Cicer arietinum L.) row ratios as intercrops under organic and limited moisture conditions in Northwest India with an aim to find out the suitable row ratio to get higher system productivity under these conditions. Chickpea, being a legume, produces nitrogen compounds that help the plant to grow itself and also makes them available to the companion wheat plants and thus helps in wheat nutrition, which otherwise becomes limited due to less mineralization of nitrogen under organic and cold weather conditions. The primary aim of the study was to get better productivity of wheat crop as this is an assured crop of this region. The intercropping system was evaluated in a randomized complete block design with four replications at Ludhiana, Punjab in Northwest India during 2013–2014 and 2014–2015. Effective tillers m−1 row length, number of grains spike−1 and 1000-grain weight of wheat were higher in wheat + chickpea (2:1) intercropping system as compared with sole wheat. This intercropping system produced significantly higher wheat grain yield, wheat equivalent yield and land equivalent ratio than sole wheat. Wheat + chickpea (2:1) and wheat + chickpea (3:1) intercropping systems gave higher water-use efficiency than sole wheat. However, chickpea gave higher yield attributes and seed yield as sole crop than that in different intercropping systems. Wheat + chickpea (2:1) and wheat + chickpea (3:1) intercropping systems produced mean wheat grain yields of 5.11 and 4.79 Mg ha−1, respectively, along with additional mean chickpea seed yields of 0.28 and 0.24 Mg ha−1, respectively.

The study was conducted to evaluate the effect of different cropping geometries on productivity, yield, and biological efficiency of red gram [Cajanus cajan (L.) Millsp] and groundnut (Arachis hypogaea L.) intercropping system under Southern Lateritic conditions of Agroecological Unit (AEU) 8 at Vellayani, Thiruvananthapuram, Kerala. The experiment, laid out in factorial randomized block design with seven treatments and three replications included sole crops and intercropping systems with varying red gram and groundnut row ratios (1:4, 1:6, 1:8, 2:4, and 4:5). Among different cropping geometries, T5 (red gram + groundnut in 4:5 ratio) recorded significantly the highest red gram seed yield (1113.49 kg ha-1) compared to other intercropping treatments though the sole crop produced higher seed yield (1305.44 kg ha⁻¹) than the crop under intercropping. While the highest kernel yield of groundnut (1186.36 kg ha⁻¹) was observed with sole crop, the highest kernel yield among the intercropping treatments was recorded with 1:6 ratio (1050.11 kg ha⁻¹). The red gram + groundnut in 1:6 ratio (T2) resulted in the highest red gram equivalent yield (REY) of 1751.10 kg ha⁻¹, demonstrating optimal resource utilization. Land equivalent ratio (LER) values exceeded 1 in all intercropping treatments, with T2 (1.37) showing the greatest advantage. Intercropping in 1:6 ratio enhanced the productivity, profitability, and sustainability by leveraging spatial and temporal resource complementarities. These findings highlighted the potential of intercropping red gram with groundnut for enhancing land-use efficiency and crop yields, making it a viable strategy for rainfed farming systems of Kerala.