Crop yield, C and N balance of three types of cropping systems on an Ultisol in Northern Lampung

AbstractThree types of cropping systems, cassava-based intercropping, hedgerow intercropping and legume cover crop rotations, were evaluated in 1994–1997 in Northern Lampung, Sumatra. The purpose of this experiment was to quantify the C and N flows returned within and transported out of plots and crop yields of different cropping systems.Cassava-based systems were not stable and yields declined over time. Intercropping cassava with rice increased cassava fresh tuber weight by 5–48% compared to the monocrop-ping system. The hedgerow intercropping gave lower maize, rice, groundnut and cowpea yields than could be obtained in a crop rotation with legume cover crops. Maize grain yields in the 80–20 rice/maize mixture were about 0.4 Mg ha−1 in the rice — groundnut rotation and about half as much when intercropped with cassava or hedgerows. Rice yields intercropped with cassava or with hedgerows were about 1 Mg ha−1 less in year 2 and 3 than those grown in rotation with groundnut. The rice yield in the first cropping season was only about 1 Mg ha−1, but in the second and third year yields in the rice — legume rotation increased to around 2 and around 3 Mg ha−1, respectively. This increase occurred despite a decline in soil organic matter content.The cassava-based systems removed much more C (7 Mg ha−1 yr-1) than the other systems, while less was returned (about 0.5–2 Mg ha−1) to the soil. In the hedgerow intercropping system about 2.5 Mg C ha−1 yr−1 was returned to the plot as biomass pruning and crop residues and about 1.5 Mg C ha−1 yr−1 was removed from the plot as yield. In the cover crop rotation 2.6 Mg ha−1 yr−1 of C was returned to the plot as crop residues plus Mucuna (only the 2nd year) and Cowpea biomass, and about 1.1 Mg ha−1 yr−1 was removed from the plot. The hedgerow intercropping systems gave an N surplus of about 15–50 kg ha−1 yr−1 returned to the soil; while the balance was 10–20 kg ha−1 yr−1 for the cover crop rotation systems and the cassava-based systems showed a negative N budget of about 60 kg ha−1 yr−1

Early planting and relay cropping: pathways to cope with heat and drought?

Maize (Zea mays) is an important food and cash crop of uplands in Southeast Asia, where it is often prone to drought and heat stress associated with climate change. This study aimed at assessing the effect of heat and drought on maize performance, testing coping strategies under such weather extremes, and understanding associated mechanisms. The experiment was carried out during 2018 in Thailand, using a split-plot design with three replications. Treatments were: July-planted maize sole cropping (control), July-planted maize-mungbean (Vigna radiata) relay cropping, and June-planted maize sole cropping. High temperatures and dry spells during July-August 2018 decreased maize growth strongest in the control and less so in maize relay cropping during generative growth stages, but not in June-planted maize sole cropping. Stress reduced maize nitrogen nutrition index by 40%. Relay-cropped maize had a significantly higher potential to keep stomata open (320 mmol m-2 s-1) than sole-cropped maize (100 mmol m-2 s-1). Δ13C of maize grains confirmed that June-planted maize (‑9.43‰) was less affected by dry spells and heat stress than July-planted sole cropped maize (‑10.23‰). Under relay cropping, the latter showed less water stress (δ13C: ‑10.12‰) compared to sole cropping and a higher soil water use. Maize was better able to cope with heat and drought stress when relayed-cropped, although less compared to early-planting of maize. Hence, the tested coping strategies are able to mitigate heat and drought effects on maize growth, while improving food security and crop diversification when relay-cropped with mungbeans

Assessing the effect of organic residue quality on active decomposing fungi in a tropical Vertisol using 15N-DNA stable isotope probing

15N-DNA stable isotope probing (15N-DNA-SIP) combined with 18S rRNA gene-based community analysis was used to identify active fungi involved in decomposition of 15N-labeled maize and soybean litter in a tropical Vertisol. Phylogenetic analysis of 15N-labeled DNA subjected to 18S rRNA gene-based community fingerprinting showed that organic residue quality promoted either slow (i.e. Penicillium sp., Aspergillus sp.) or fast growing (i.e. Fusarium sp., Mortierella sp.) fungal decomposers in soils treated with maize or soybean residues, respectively, whereas Chaetomium sp. were found as dominant decomposers in both residue treatments. Therefore, we have clear evidence that specific members of the fungal community used 15N derived from the two different organic resources for growth and stimulated early decomposition of maize or soybean decomposition. In conclusion, our study showed that 15N-DNA-SIP-based community analyses cannot only follow the flow of N from organic resources into bacteria, but also into the actively decomposing fungal communities of soils

Agroforestry Interactions in Rainfed Agriculture: Can Hedgerow Intercropping Systems Sustain Crop Yield on an Ultisol in Lampung (Indonesia)?

The productivity of rainfed agriculture land developed on Ultisols is limited by physical and chemical constraints. These problems can be solved and consistently high yields obtained only by the development of comprehensive manage-ment systems. In the 1980s, hedgerow inter-cropping was promoted initially for improving soil fertility and sustainability of crop production on nutrient-depleted soils. However the previous enthusiasm for hedgerow intercropping is unsupported by scientific evidence and its labour demand too high. The question remains, is there a window of opportunity where the biophysical principle of hedgerow intercropping is sound? Research to compare the long-term performance of crops and trees in hedgerow intercropping and monocluture cropping is needed. This research has been conducted at long-term field experiment station at the BMSF-Project, Lampung, Indone-sia. The experiment site had non-nitrogen-fixing peltophorum (PP), nitrogen-fixing gliricidia (GG) and alternate peltophorum and gliricidia (PG) hedgerow intercropping and maize / groundnut monoculture (C) treatments. We concluded that the net interactions related to soil fertility and competition for growth resources in peltophroum were positive for crop yield in PP and PG but negative for GG. Even so, the PP and PG sys-tems resulted in similar yields as monocropping; however, hedgerow intercropping considerably improved soil fertility attributes

An analysis of the economic values of novel cropping systems in N. E. Thailand and S. Sumatra

AbstractThe use of food-crop intercropping, hedgerow intercropping and secondary or cover cropping to increase incomes of resource-poor farmers in South East Asia was investigated. Since all systems improve conservation of nutrients and most give extra marketable produce, they were expected to increase farm profitability. On upland farms in Lampung, South Sumatra, both inter- and secondary crops were found to improve yields compared with cassava monocropping and thus the income derived from growing cassava or rice with maize. These increases were equivalent to between 70 and 440 US dollars per hectare. An economic analysis of the lowland rice-producing systems in North East Thailand suggested that with the exception of growing cowpea, the use of pre-rice cover crops was not profitable despite a substantial increase in rice yield, because the additional labour cost more than the additional income was worth. A benefit of leguminous crops, however, can be the extra marketable product. Groundnut in Indonesia and cowpea in Thailand gave an attractive extra US$400–1150 total income increase per hectare per year (i.e. extra yield of the main food crop plus extra marketable produce from the secondary crop) even after the additional costs were deducted. Hedgerow intercropping gave smaller profit margins of about US$ 90. Although both hedgerow intercropping and secondary cropping represent a considerable investment of labour by farmers, this investment may be more feasible than paying for fertilizer on credit. On balance the most attractive option tested was the use of a leguminous secondary crop, e.g. groundnut or multipurpose cowpea, within the food crop cycle

Effect of Toposequence Position on Soil Properties and Crop Yield of Paddy Rice in Northern Mountainous Region, Vietnam

Symposium Pape

The potential of conservation agriculture to improve nitrogen fixation in cowpea under the semi-arid conditions of Kenya.

Open Access Journal; Published online: 07 Oct 2022Low-cost but productive crop intensification options are needed to assist smallholder farmers in the tropics to move away from poverty. This study assessed the capacity of cowpea (Vigna unguiculata (L.) Walp.) to perform biological N fixation (BNF) under no-tillage practices, crop residue cover and intercropping with maize (Zea mays L.). The study was performed during the long rains of 2017 at Kiboko experimental station, located in semi-arid eastern Kenya. The research field trials had been running for three years (6 cropping seasons) by the time the sampling took place. The experimental set up was a split-plot design: main plots being tillage system (no till + maize stover retention (CA), and conventional tillage to 15 cm depth without mulch retention (CT)), sub-plot being cropping system (maize-cowpea intercrop, maize monocrop, and cowpea monocrop). Cowpea plants were sampled at 50% flowering stage and at physiological maturity to investigate biomass production and %N derived from the atmosphere (%Ndfa) through the 15N natural abundance technique, using maize as a reference control. Results showed that the number of nodules per plant was higher in CA treatments rather than in CT although not significant (p>0.05). Mean cowpea grain yield at harvest varied between 472 – 590 kg ha‐1 in intercrops whereas grain yield in monocrops was between 1465 - 1618 kg ha-1. Significant differences were however recorded between treatments with CT monocropped cowpea at flowering recording the highest mean %Ndfa (62%) and CT intercrop the lowest (52%). At harvest stage CA inter recorded the highest %Ndfa (54%) while CT intercrop the lowest (41%). The %Ndfa was higher (p<0.05) at flowering (between 57- 69%) compared with 45 - 64 % at harvest stage. Overall cowpeas in intercrops derived between 17.8 - 22.8 kg ha-1 of their total N from atmospheric dinitrogen fixation while monocrops between 54.9 - 55.2 kg ha-1. The effect of CA on BNF was positive but not significantly different from CT. These results suggest that CA has the potential to enhance the BNF process but there is a need to explore in future alternative spatial arrangement and variety choice in intercropping of cowpea and maize to optimize the BNF process

Spatial differences in soil properties, crop yield and methane emission from paddy rice cascade, Northwest Vietnam

Session 2: Nitrogen, Green House Gasses and Agricultur

Nitrogen use efficiency of monoculture and hedgerow intercropping in the humid tropics

The design of productive and efficient intercropping systems depends on achieving complementarity between component speciesrsquo resource capture niches. Spatiotemporal patterns of capture and use of pruning and urea nitrogen (N) by trees and intercrops were elucidated by isotopic tracing, and consequences for nitrogen use efficiency were examined. During the first cropping season after applying urea–15N, maize accounted for most of the plant 15N recovery in Peltophorum dasyrrachis (33.5%) and Gliricidia sepium (22.3%) hedgerow intercropping systems. Maize yield was greatest in monoculture, and maize in monoculture also recovered a greater proportion of urea 15N (42%) than intercropped maize. Nitrogen recovery during active crop growth will not be increased by hedgerow intercropping if hedgerows adversely affect crop growth through competition for other resources. However, hedgerows recovered substantial amounts of 15N during both cropping cycles (e.g. a total of 13–22%), showing evidence of spatio-temporal complementarity with crops in the spatial distribution of roots and the temporal distribution of Nuptake. The degree of complementarity was species-specific, showing the importance of selecting appropriate trees for simultaneous agroforestry. After the first cropping season 17–34% of 15N applied was unaccounted for in the plant-soil system. Urea and prunings N were recovered by hedgerows in similar amounts. By the end of the second (groundnut) cropping cycle, total plant 15N recovery was similar in all cropping systems. Less N was taken up by the maize crop from applications of labelled prunings (5–7%) than from labelled urea (22–34%), but the second crop recovered similar amounts from these two sources, implying that prunings N is more persistent than urea N. More 15N was recovered by the downslope hedgerow than the upslope hedgerow, demonstrating the interception of laterally flowing N by hedgerows