Diversified agroforestry systems improve carbon foot printand farmer’s livelihood under limited irrigation conditions

Increasing weather aberrations cause frequent crop failure in monoculture cropping system. Specialized crop production systems, where few seasonal crops occupy vast arable lands, resulting in more biotic and abiotic stresses in agri-ecosystem. Therefore a diversified agroforestry systemwas evaluated to ensure resilience underlimited water conditions, with an aim to augment carbon footprint with enhanced productivity and profitability. The study hypothesised that integration of perennial fruits trees with seasonal crops will have benign effect for sequestering more carbon and improving livelihood of the farmers. This is one of the first timesthat arid fruits tress along with leguminous,and other low water requiring crops were studied for improved carbon sequestration, livelihood of the farmers andfor better resilience in production system. The experimental findings showed that arid fruit trees along with leguminous, oilseeds and cash crops resulted in higher profitability and thus improved livelihood of the farmersin arid and semi-arid areas of South Asia. Diversified phalsa-mung bean-potato and moringa-mung bean-potato were the most productive agroforestry system (36.7t/ha and 36.2 t/ha respectively. Under limited irrigation conditions, Karonda (Carisa spp.)-mung bean potato system was found best in improving livelihood with maximum net return of $ 3529.1/ha with higher profitability/day ($ 19.9/day). Phalsa -MB-potato system was also recorded maximum water use efficiency (33.0 kg/ha-mm), whereas density of SOC was in Phalsa-cowpea-mustard (9.10 Mg/ha) and moringa-mung bean -potato AFS (9.16 Mg/ha). Carbon footprint analysis revealed that maximum net C gain was in Phalsa-mung bean -potato system (7030 Carbon equivalent kg CE/ha/year).


Introduction
India is one of the leading nations in irrigated (68.38Mha) as well as in rainfed (86 Mha) arable lands 62 globally (1). Escalating climatic risks are leading to huge loss to the farmers. Appropriate land-use 63 systems which ensure resilience by minimizing the impact of climatic vulnerabilities arecrucial for 64 livelihood security and are integral part of mitigation strategies to climate change. Agroforestry is one 65 such land use system that may potentially support livelihood through simultaneous production of 66 food, fodder and firewood as well as mitigation and adaptation to climate change .Due to changing 67 climate scenarios, natural resource degradation is projected as a serious problem in the years to come

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(2). In this context, the perennial fruits trees have been identified usually more resilient to 69 environmental constraints due to better capability to cope up with aberrant weather conditions and multifunctional biomass production even on marginal land (3) against annual 71 crops.However,integration of seasonal crops with compatible fruit trees are key for successful 72 cultivation in challenged ecosystem like arid and semi arid, also the performanceof different crop 73 species varies depending on the growing conditions (4).Numerous studies revealed that fruit based 74 agroforestrymodels (AHM) are the promising land use systems because these conservesoil and 75 moisture, reduces soil erosion, sustains production and income at higher levels (4, 5,6). The system 76 also increases carbon sequestration in the soil, due to decomposition of litter fall of fruit trees. This 77 contributesin enhanced biological activity for the stability of rhizospheric environment. The 78 agroforestrysystem is also supportive in generating additional employment, especially during off-79 season. It also provides scope for auxiliary industries like processing (preserves, jam, jelly, etc.), 80 essential oils extraction, transportation, packaging, etc.Agroforestry systems have been identified 81 potential solution for the twin climate and food security challenges (6).

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Even in irrigated areas, due toincreasing biotic and abiotic stresses, ithas become a daunting task to 83 achieve sustainably high farm productivity.Agroforestry systems involving trees and crops into fallow 84 periods between two cropping seasonscan lead to higher crop yields in many parts of the tropics (7),

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and increased well-being of the farmers (8). This will certainly reduce the riskin farming even under 86 stressed agri-ecosystems. Furthermore, with the adoption of location specific AFS as part of 87 integrated farming system IFS) approaches will improve overall livelihood of the farmers. In India,

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55% of arable lands are rainfed and this is the high time to make them sustainable, productive and risk 89 free production systems. Single crop based management strategies will not help in achieving these 90 goals under limited water ecologies, especially in rainfed areas. The integration of more agriculture 91 and allied activities with field crops will certainly help in creating a sustainable agri-92 ecosystem.Integration of annual crops with fruit trees yields manifold benefits through secure 93 production, income generation and restoration of ecosystem services (9-10) in a sustainable manner.   Where, SOC f and SOC i are the SOC (Mg/ha) in the final and initial soils, respectively, and n 168 represents number of years of thestudy (11).

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The C sequestration through different systems was calculated in terms of increases in C stock in soil.

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Data on initial and finalSOCconcentrations in the various treatments were collected for all plots.

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Mass of soil organic carbon (MSOC) was estimated as below: The

Biomass and productivity 207
Integration of rainy season crops in AFS, resulted in higher green pod yield of CP from karonda based 208 AFS, which was closely followed by moringa-CP-AFS (Table3). Among fruits trees, phalsa and 209 moringa produced maximum fruits (13.0-14.5 t/ha) and least was from guava (Table 3). Seed yield of 210 MB, a leguminous complementary crop in AFS, produced maximum underphalsa-based AFS.

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Moreover, mungbean under moringa-basedAFS was also resulted in almost equal seed productivity.

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The system productivities ofphalsa-CP (20.5 t/ha) and moringa-CP (19.6 t/ha) AFSwerehigherthan 213 remaining combinations ofagroforestry systems during rainy seasons.Potato and mustard were taken 214 as intercrops in AFS during rabi seasons. The tuber potato resulted in higher productivity ofMoringa 215 based AFS (22.5 t/ha), closely followed by Karonda-potato system (22.0 t/ha). The seed yield of 216 mustard was 1.6-1.75 t/ha (Table 3). Thus every drop of water is efficiently utilized for production of 217 different crops. The data revealed thatphalsa-MB-potato was the most productive AFS (36.7t/ha), 218 moringa-MB-potato was also have higher system productivity (36.2 t/ha). In these two AFS, fruit 219 yieldswere also higher, which resulted in higher system productivity. Maximum system productivity 220 was obtained from phalsa-mungbean-potato agroforestry system, which was closely followed by

Economics and profitability 224
With regards to economics, potato in AFS resulted in higher net returns ($1970.9-2156.1/ha).

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However, with inclusion of mustard in AFS, the net return was ($593.9-654.8/ha) higher than guava 226 based AFS. The benefit: cost (B:C) ratio was >2.0 in potato based AFS in all fruit crops while 227 remained lesser (1.87-2.06) in mustard integration with fruit trees (Table 4). However, lowest system 228 productivity was in guava-CP-mustard AFS. With respect to profitability, maximum net system return 229 was obtained from karonda-MB-potato system due to better prevailing market prices of the 230 component commodities in the system. Similar was the trend in system profitability, system 231 production efficiency. However, maximum B:C ratio was in karonda-MB-mustard system, as mustard  (Table 4).

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Water use efficiency and water use dynamics  (Table 6). Similar was the trend in mass of SOC and maximum density of SOC was in phalsa-CP-256 mustard (9.10 Mg/ha) and moringa-MB-potato AFS (9.16 Mg/ha). Carbon footprint analysis revealed 257 that maximum net C gain was in phalsa-MB-potato system (Table 7) and least was in guava and 258 karonda based AFS. After Phalsa based AFS, Moringa also resulted in significant higher build-up of 259 carbon in soils. Among AFS, Phalsa based AFSresulted in maximum carbon sequestration rate potential (Fig 2).It is also evident that in surface soil (0-15 cm) higher carbon sequestration rate 261 potential (CSRP) was observed (0.48-0.73 Mg/ha/year), whereas in deeper soils (15-30 cm) it ranged 262 between 0.4-0.62 Mg/ha/year (Fig 3). Maximum CSRP was in Phalsa based AFS, which was due to 263 higher biomass addition in soil from the system. Most of the organic residues remain on soil surface 264 and it decreases with increase in soil depth due to lesser accumulation in the soil layers. Even in

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The growth parameters of the field crops were found higher in Moringa based AFS. This was due to 272 the fact that Moringais multi propose trees, it fixes substantial amount of atm -N in to the soil (14 -15 273 13). There was less competition between the trees and the field crops, this ultimately resulted in 274 higher biomass accumulation and better canopy spread in terms of higher LAI (Table 2). Maximum

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Moringatrees are also valuable for alley cropping systems because they fix nitrogen which is supplied 283 to intercrops via the pods and leaves they produce (15).Among the field crops, maximum range in 284 AGR was recorded in mustard (0.60 gday -1 ) and least was in case of MB (0.18 gday -1 ). The effect of 285 shedding under AFS on mustardvaried due to the fact of differential response of plant to rhizospheric 286 and aerial environment, and also some tree species led to allelopathic effect on mustard which  another leguminous intercropwasgrown in AFS produced maximum under phasla based system.

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Maximum system productivity was obtained from Phalsa-MB-potato and Moringa-MB-potato AFS.

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Pareek and Awasthi(21) spelled out higher system productivity under Phalsa based AFS and higher 309 intercrop yield due to less competition for nutrients and water and recommended the synergy of 310 phalsa in AFS. This was due to the fact that more space was available in alleys of Phalsa, causing no 311 shedding effect on crops. Also good amount of leaf fall was added in the system (22).

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Hence,agroforestry systems are economically viable, productive and also create employment round 313 the year.

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Economics and profitability 315 Inclusion of cash crop like potato in AFS resulted in higher net returns compared to mustard in AFS.

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But comparatively lesser cost of cultivation was involved in mustard over potato system (23).Hence to profitability, maximum net system return was obtained from karonda-MB-potato system due to 324 better prevailing market prices of the component commodities in the system. Similar was the trend in 325 system profitability, system production efficiency. The maximum B: C ratio was in karonda-MB-326 mustard system. This was due to the fact that mustard involved comparatively lesser cost of 327 cultivation (19, 23). And highest cost of cultivation was with potato inclusion during rabi season.