The demand for food in Bangladesh is increasing due to the increasing population. Land is the primary natural resource that affords habitat and sustenance for living beings. In Bangladesh, the ...coastal areas cover an area of 47,201 km2 or 32 % of the total land under 19 districts of Bangladesh. The coastal southern saline and non-saline areas are vulnerable to water logging conditions and farmers cannot grow any crops except dry season (rabi). However, in some areas, farmers are trying to use their indigenous technologies to combat natural disasters to ensure food security. For example, floating, sorjan or raised bed systems are potential and farmers are practicing in these areas. Among these techniques, the sorjan bed system is one of the potential techniques that is extensively used in southern Bangladesh, particularly water logging conditions to improve food security. To enhance the production and make land cultivation profitable, the experiments were carried out at the farmers’ fields under the sorjan system in consecutive two growing seasons. The sole crop was brinjal (cv. BARI Begun-12), BARI Lalshak-1 (cv. Red amaranth), BARI Dhania-1 (cv. Coriander leaf), Cauliflower (cv. Cold queen), Cabbage (cv. Equatoria) and Knol Khol were utilized as intercropping with brinjal. The treatments were i) Sole brinjal, ii) Brinjal + Red amaranth, iii) Brinjal + Coriander leaf, iv) Brinjal + Cauliflower, v) Brinjal + Cabbage, and vi) Brinjal +. 24-day-old seedlings of the BARI Begun-12 grown in a nursery bed were transferred to the plots where the seeds of Red amaranth and Coriander leaf were directly sown. However, the seedlings of Cauliflower, Cabbage, and Knol Khol were also transplanted to the field after one week of transplanting brinjal. The results exposed that sole crops had the highest results in terms of days to flowering, days to first fruit set, days to first harvesting, leaf area, fruit length, fruit breadth, single fruit weight, fruits plant−1, fruit yield, TSS %, and dry matter %. In both years, brinjal exhibited the highest yield as the sole crop compared to intercropping. 48.12 t/ha and 46.27 t/ha in the first and second cropping seasons, respectively. In the first cropping season, Red amaranth, Coriander leaf, Cauliflower, Cabbage, and Knol Khol performed with a yield of 10.12, 7.23, 23.14, 22.87, and 9.05 t/ha. During the second cropping season, the same crops exhibited a yield of 10.05, 7.01, 23.09, 22.68, and 9.98 t/ha. The highest land equivalent ratio, gross return, net return, and BCR were obtained from brinjal-cauliflower intercropping, which was 1.74, 1049300 BDT, 553820 BDT, and 2.12, respectively, in the 2021–2022 cropping season and 1.78, 1057900 BDT, 562010 BDT, and 2.13, respectively, in the next season in 2022–2023. This intercropping approach resulted in a higher land equivalent ratio, net return, and benefit-cost ratio of 1.76, 557915 BDT, and 2.125, respectively, over the average of two successive cropping seasons.
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•The demand for food in Bangladesh is increasing due to the increasing population.•Land is the primary natural resource that affords habitat and sustenance for living beings.•The coastal southern saline and non-saline regions are vulnerable to water logging conditions.•Although in these areas, farmers use indigenous non-profitable technologies to combat natural disasters to ensure food security.•The sorjan farming system has been found a potential, profitable and environmentally friendly farming practice in these vulnerable areas.
Little is known about productivity of smallholder maize–pigeonpea intercropping systems in sub-Saharan Africa. We conducted a survey of 277 farm households in Northern Tanzania to assess ...socio-economic factors, field management characteristics, and their association with productivity of maize–pigeonpea intercrops. On each farm, crop assessments were focused on a field that the farmer identified as most important for food supply. Variables associated with yields were evaluated using linear regression and regression classification. Biomass production ranged between 1.0 and 16.6 for maize, and between 0.2 and 11.9 t ha
−1
for pigeonpea (at maize harvest). The corresponding grain yields ranged between 0.1 and 9.5 for maize, and between 0.1 and 2.1 t ha
−1
for pigeonpea. Plant density at harvest, number of years the field had been cultivated, slope, weeding, soil fertility class, fertiliser and manure use were significantly associated with variation in maize grain yield, with interactions among the factors. Fields on flat and gentle slopes with plant density above 24,000 ha
−1
had 28% extra yields when fertiliser was applied, while less than 24,000 plants ha
−1
yielded 16% extra yield when manure was applied. Plant density at harvest was the key factor associated with pigeonpea yield; fields with densities above 24,000 plants ha
−1
yielded an average of 1.4 t ha
−1
, while less than 24,000 plants ha
−1
yielded 0.5 t ha
−1
. We conclude that performance of intercrops can be enhanced through application of organic and inorganic nutrient sources, and agronomic interventions including weeding, implementing soil conservation measures on steep slopes and optimising plant density.
Field experiments were carried out during three successive years to study through a dynamic approach the competition for soil N and its interaction with N2 fixation, leaf expansion and crop growth in ...pea–barley intercrops. The intensity of competition for soil N varied between experiments according to soil N supply and plant densities. This study demonstrates the key role of competition for soil N which occurs early in the crop cycle and greatly influences the subsequent growth and final performance of both species. Relative yield values for grain yield and N accumulation increased with the intensity of competition for soil N. Barley competed strongly for soil N in the intercrop. Its competitive ability increased steadily during the vegetative phase and remained constant after the beginning of pea flowering. The period of strong competition for soil N (500–800 degree-days after sowing) also corresponded to the period of rapid growth in leaf area for both species and therefore an increasing N demand. For each species, the leaf area per plant at the beginning of pea flowering was well correlated with crop nitrogen status. Barley may meet its N needs more easily in intercrops (IC) and has greater leaf area per plant than in sole crops (SC). Barley having a greater soil N supply results in an even higher crop N status and greater competitive ability relative to pea in intercrop. Competition by barley for soil N increased the proportion of pea N derived from fixation. The nitrogen nutrition index (NNI) values of pea were close to 1 whatever the soil N availability in contrast to barley. However N2 fixation started later than soil N uptake of pea and barley and was low when barley was very competitive for soil N. Due to the time necessary for the progressive development and activity of nodules, N2 fixation could not completely satisfy N demand at the beginning of the crop cycle. The amount of N2 fixed per plant in intercrops was not only a response to soil N availability but was largely determined by pea growth and was greatly affected when barley was too competitive.
Declining soil fertility and climate change have led to a reduction in potato yield and thus negatively affected the livelihood of communities that rely on the crop. A study was conducted in ...Nyandarua County, Kenya, for two seasons to evaluate the potential of potato-legume intercropping in enhancing N and P uptake and use efficiencies and on potato fresh tuber and equivalent yield (PEY). Potato equivalent yield compares system performance by converting the yield of legume crops into equivalent potato yield based on prevailing market prices. Treatments comprised two potato-legume intercrops: lima bean (
Phaseolus lunatus
L.) and lupin (
Lupinus albus
L.), and two inorganic fertilizers: Di-ammonium phosphate (18:46:0), composite NPK (17:17:17), and a no input control. Treatment combinations were as follows: (i) sole potato, (ii) potato-lima beans and (iii) potato-lupin intercrops. Fertilizers were applied to each of the three cropping systems separately. Higher N uptake was found in sole potato (73.5 kg ha
−1
), which was more than double that recorded in potato-lupin (35.9 kg ha
−1
) and 60% more than that recorded in potato-lima beans intercrop (46.8 kg ha
−1
). On the other hand, N use efficiency was higher in potato-lupin (240.6 kg PEY kg
−1
N supply) and sole potato (238.6 kg PEY kg
−1
N supply) and lowest in potato-lima beans (139.0 kg PEY kg
−1
N supply). Intercropping resulted in a decrease in fresh tuber yield by more than 70% while the equivalent yield decreased by almost 15 Mg ha
−1
. The application of fertilizer did not enhance the recovery of the yield loss. The study establishes that the choice of companion legumes in intercropping can significantly influence nutrient uptake and use efficiency, and thus the yield of the potato crop.
In a previous paper Bedoussac L, Justes E (2009) Plant Soil, doi: 10.1007/s11104-009-0082-2, we showed that intercropping of durum wheat and winter pea increased the yield and protein concentration ...of durum wheat when early N availability was less than 120 kg N ha⁻¹. The aim of the present work was to understand these results by analysing intercrop species dynamics for growth, light and N acquisition. A 2-year field experiment was carried out in southwest France with different fertilizer-N levels in order to compare wheat (Triticum turgidum L.) and pea (Pisum sativum L.) grown as sole crops and as an intercrop in a row substitutive design. The advantages of intercropping in low N conditions were due mainly to: (1) better light use (up to 10%), thanks to species dynamic complementarity for leaf area index and height; (2) growth complementarity over time (higher growth rate of wheat until pea flowering and then of pea until wheat flowering); and (3) dynamic complementary N acquisition associated with better wheat N status throughout growth. Disadvantages, underlining poorer complementarity within the intercrop stand, were observed with ample available N in early growth. This induced higher cereal growth during winter, which led to increase interspecies competition by reducing pea light absorption and, consequently, its biomass production.
The merits of three climate smart agriculture (CSA) technologies implemented by farmers were assessed in Machinga district of Malawi with respect to their soil quality and maize yield effects. Data ...were collected from farms implementing the three CSA technologies, namely conservation agriculture (CA), maize–pigeonpea (Maize‐PP) intercrops and a local organic and inorganic soil amendment known as Mbeya fertilization (Mbeya‐fert), from 2018 to 2019. With respect to resilience and adaptation, particulate organic matter, soil organic carbon (SOC), N, P, K, Ca and Mg all significantly improved while bulk densities were lowered under the three CSA systems. Higher annual biomass inputs and improved water infiltration from the Maize‐PP intercrops were observed. With respect to productivity, CA and Mbeya‐fert improved maize yields by 51 and 19%, respectively, compared to conventional farmer practices. With regard to climate change mitigation, increases in measured SOC in the top 20 cm depth compared to the conventional farmer practices amounted to 6.5, 12 and 10.5 t C ha−1 for CA, Mbeya‐fert, and Maize‐PP intercrops, respectively, over a period of 2–6 years. This suggests higher potential for carbon sequestration from CSA technologies. Furthermore, use of drought tolerant varieties, timely weeding and optimum plant populations, increased productivity. Improved gross margins from CSA practices were also apparent. Thus, employing these CSA technologies could enable farmers to be more resilient, productive and adapt better to climate change shocks leading to improved food security and livelihoods.
An experiment was conducted to manage the eggplant (brinjal) shoot and fruit borer Leucinodes orbonalis Guenée (Lepidoptera: Crambidae), the leafhopper Amrasca biguttula biguttula (Ishida) ...(Hemiptera: Cicadellidae), and the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) during kharif, the southwest monsoon season (Jul-Oct), in 2010 and 2011 at an experimental farm at the Division of Entomology, Indian Agricultural Research Institute, New Delhi. The experiment consisted of 7 different treatments with brinjal or eggplant ‘Pusa Kranti’, Solanum melongena L. (Solanales: Solanaceae), as the main crop and coriander, marigold or mint as intercrops, along with a border crop (maize or cowpea) acting as refuge crops. Treatment T1 (maize as border crop and coriander as intercrop) harbored the smallest cumulative mean leafhopper population (6.90 insects per 3 leaves per plant) and the next to smallest mean whitefly population (9.64 insects per 3 leaves per plant) during monsoon season of 2010 and 2011. Treatment T3 (maize as border crop and marigold as intercrop) was second best in reducing the leafhopper population (7.27 insects per 3 leaves per plant), while it was the best treatment in reducing the whitefly population (8.36 insects per 3 leaves per plant). The sole crop (T7) harbored the largest whitefly (20.17 insects per 3 leaves per plant) and leafhopper (12.61 insects per 3 leaves per plant) populations among the 7 treatments. The lowest mean percentage fruit infestation was recorded from treatment T1 (by number: 27.72; by weight: 27.81). All the treatments involving intercrops showed significantly lower percentage fruit infestation by L. orbonalis than eggplant alone (T7, control), which showed 37.73% infestation by number of fruits and 38.13% by weight of the fruits. The greatest mean number of coccinellids (1.25 per plant) and largest Shannon-Wiener indices were recorded from treatment T1 (maize and coriander). The smallest mean number of coccinellids (0.37 per plant) and smallest Shannon-Wiener indices were recorded from the sole crop control, T7. Various plant volatiles present in the intercrop were identified by the thermal desorption technique. Twenty one volatile compounds were present in coriander, 7 in marigold, and 18 in mint. The current state of knowledge of the behavioral effects (repellency, attractancy, no effect) of each chemical with respect the various herbivorous insects and natural enemies is summarized and this information will facilitate quantitative studies on how different pest and beneficial insects respond to plant volatiles in polycultures.
Background and aims The selection of legume species and species mixtures influences agroecosystem nitrogen (N) and carbon cycling. We utilized a fertility gradient to investigate the effects of plant ...species interactions on biological N fixation of an annual and perennial legume in response to shifting soil resource availability. Methods Legume N fixation of annual field pea (Pisum sativum) and perennial red clover (Trifolium pratense) grown in monoculture and mixtures with oats (Avena sativa) or orchardgrass (Dactylis glomerata) was estimated using the 15N natural abundance method across 15 farm fields and we measured six soil N pools ranging from labile to more recalcitrant. Results Evidence of complementary and facilitative species interactions was stronger for the perennial red clover-orchardgrass mixture than for the annual field pea-oat mixture (N Land Equivalency Ratios were 1.6 and 1.2, respectively). We estimated that the transfer of fixed N from red clover to orchardgrass increased aboveground N fixation estimates by 15% from 33 to 38 kg N ha−1. Despite a more than 2-fold range in soil organic matter levels and more than 3-fold range in labile soil N pools across field sites, the N fertility gradient was not a strong predictor of N fixation. While grass N assimilation was positively correlated with soil N pools, we found only weak, inverse correlations between legume N fixation and soil N availability. In grass-legume mixtures, soil N availability indirectly influenced N fixation through plant competition. Conclusions These results suggest that increasing diversity of cropping systems, particularly through the incorporation of perennial mixtures into rotations, could improve overall agroecosystem N cycling efficiency.
In Malawi, N and P deficiencies have been identified as major soil fertility constraints to maize (Zea mays, hybrid NSCM 41) productivity. In this study, we evaluated the effect of three rates of N ...and P fertilizers on maize performance in monoculture and maize intercropped with the nitrogen fixing legume gliricidia (Gliricidia sepium) in replicated field trials run for four years (2002/03-2005/06 seasons) at Makoka, in southern Malawi. Significant season-to-season variation was found in stand loss, ears per plant, stover yield, grain yield and thousand kernel weight (TKW), which was related to distribution of rainfall received during the growing season. All variables were significantly higher in the gliricidia/maize intercrop compared with monoculture maize. During the four consecutive cropping seasons, grain yields of maize increased by 343% (i.e. from 0.94 tons ha-¹ in unfertilized sole maize to 4.17 tons ha-¹ in gliricidia/maize intercropping). Optimum synergistic effect on grain yield (38% increase over unfertilized gliricidia/maize) was obtained when half recommended N and P rates were combined with gliricidia indicating interspecific facilitation. Response surface modelling showed that the optimum combination of factors for maximum grain yield (4.2 t ha⁻¹) in monoculture maize was 80 kg N ha⁻¹, 31 kg P ha⁻¹ and 917 mm seasonal rainfall. In the gliricidia/maize intercrop, the stationary point had no unique maximum. Ridge analysis revealed that the estimated ridge of maximum grain yield (5.7 t ha⁻¹) in the intercrop is when 69 kg N ha⁻¹, 37 kg P ha⁻¹ is applied and a seasonal rainfall of 977 mm is received. The total P uptake in the intercrop (14.3 kg ha⁻¹) was significantly higher than that in maize monoculture (6.6 kg ha⁻¹). P uptake was significantly (P = 0.008) influenced by P fertilizer rate. Therefore, we conclude that combining inorganic N and P fertilizers with organic inputs from gliricidia has positive and synergistic effects on maize productivity in southern Malawi.
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