The objective is to describe the hydraulic infrastructure and social organization in a small system of non-conventional irrigation locally known as presas. The technique consists in controlling runoff and retaining th...The objective is to describe the hydraulic infrastructure and social organization in a small system of non-conventional irrigation locally known as presas. The technique consists in controlling runoff and retaining the soil, which has dragged with it. For that the local inhabitants must increase the height of a series of walls built with stones arranged in beds of dry streams. The information was obtained with field tours, interpretation of topographic charts and interviews with users of the presas. We conclude that the permanence of the system depends on the knowledge to control runoff, the availability of plant varieties adapted to the local ecology, the widespread use of oxen for agricultural work, as well as the social arrangements that allow the maintenance of the hydraulic infrastructure.展开更多
Sorghum (Sorghum bicolor L. Moench) is cultivated as monocrop in Eritrea. Efforts were made to grow sorghum-pigeonpea (Cajanus cajan L. Millspp.) intercrop on the tillage, fertilizers and supplementary irrigations nec...Sorghum (Sorghum bicolor L. Moench) is cultivated as monocrop in Eritrea. Efforts were made to grow sorghum-pigeonpea (Cajanus cajan L. Millspp.) intercrop on the tillage, fertilizers and supplementary irrigations necessary for sorghum. Experiments were conducted in terraced fields at Hamelmalo during 2013-15 to evaluate growth and yield of sorghum-pigeonpea intercrop in split plot design with conventional tillage (CT), reduced tillage (RT) and zero tillage (ZT) in main plots and rainfed (I<sub>0</sub>), 50% of full irrigation (I<sub>1</sub>), 75% of full irrigation (I<sub>2</sub>) and 100% of full irrigation (I<sub>3</sub>) in subplots. All irrigations were stopped 15 days before sorghum maturity. Full irrigation was 60 mm applied at 50% depletion of available soil water in 1 m profile. Sorghum growth was faster than pigeonpea until 85 days from planting and pigeonpea growth accelerated only after sorghum harvesting. About 80% of sorghum roots were within 0.6 m profile but more than 75% of pigeonpea roots were below 0.60 m depth. This showed a weaker competition between the two crops for nutrients, water and light. Both grain and stover yields of sorghum were optimum in RT + I<sub>2</sub> during the 2 years. Highest grain yield was 6900 kg·ha<sup>-1</sup> in RT + I<sub>3</sub> in 2013, which was at par with that in RT + I<sub>2</sub>. Mean residual soil moisture at sorghum harvesting was 74 mm·m<sup>-1</sup>, which decreased to 8 mm·m<sup>-1</sup> by pigeonpea harvesting. Residual moisture was more in the irrigated than non-irrigated plots. Pigeonpea yields were optimum (1363 kg·ha<sup>-1</sup>) in RT + I<sub>3</sub> and lowest (297 kg·ha<sup>-1</sup>) in ZT + I<sub>0</sub>. Average water use by sorghum-pigeonpea was 374 mm by sorghum harvesting and 438 mm by pigeonpea harvesting, producing total sorghum equivalent yield of 7475 kg·ha<sup>-1</sup>. This raised average water use efficiency from 12.6 kg·ha<sup>-1</sup>·mm<sup>-1</sup> at sorghum harvesting to 17.1 kg·ha<sup>-1</sup>·mm<sup>-1</sup> at pigeonpea harvesting. Benefit was doubled at 50% of full irrigation and >4 times at 75% of full irrigation.展开更多
A field experiment was conducted for two consecutive years at North Eastern Indian Himalayan region to assess the effect of soil moisture conservation measures on soil and water productivity of different rainfed maize...A field experiment was conducted for two consecutive years at North Eastern Indian Himalayan region to assess the effect of soil moisture conservation measures on soil and water productivity of different rainfed maize(Zea mays L.)-based cropping sequences.Results revealed that double mulching with in-situ maize stover mulch(MSM)+fresh biomass of white hoary pea(WHP-Tephrosia candida)and MSM+fresh biomass of ragweed(RW-Ambrosia artemisiifolia)improved soil moisture content(SMC)and leaf relative water content of crops during dry season.The soil organic carbon(SOC)content and stocks under MSM+WHP and MSM+RW mulches were significantly higher than that under no mulch at 0-15 cm depth.The soil microbial biomass carbon and dehydrogenase activity were maximum under MSM+WHP/RW.The highest system productivity was obtained from maize-French bean(Pole type-PT)sequence under MSM+RW followed by MSM+WHP.The water productivity was the highest under MSM+WHP.While SOC content was the highest under maize-French bean(PT),the maximum plant available nitrogen and phosphorus were obtained under maize-black gram sequence.Thus,double mulching technology involving MSM and RW(available in plenty)is a viable option for improving soil,crop and water productivity under rainfed hill ecosystems of eastern Indian Himalayas.展开更多
文摘The objective is to describe the hydraulic infrastructure and social organization in a small system of non-conventional irrigation locally known as presas. The technique consists in controlling runoff and retaining the soil, which has dragged with it. For that the local inhabitants must increase the height of a series of walls built with stones arranged in beds of dry streams. The information was obtained with field tours, interpretation of topographic charts and interviews with users of the presas. We conclude that the permanence of the system depends on the knowledge to control runoff, the availability of plant varieties adapted to the local ecology, the widespread use of oxen for agricultural work, as well as the social arrangements that allow the maintenance of the hydraulic infrastructure.
文摘Sorghum (Sorghum bicolor L. Moench) is cultivated as monocrop in Eritrea. Efforts were made to grow sorghum-pigeonpea (Cajanus cajan L. Millspp.) intercrop on the tillage, fertilizers and supplementary irrigations necessary for sorghum. Experiments were conducted in terraced fields at Hamelmalo during 2013-15 to evaluate growth and yield of sorghum-pigeonpea intercrop in split plot design with conventional tillage (CT), reduced tillage (RT) and zero tillage (ZT) in main plots and rainfed (I<sub>0</sub>), 50% of full irrigation (I<sub>1</sub>), 75% of full irrigation (I<sub>2</sub>) and 100% of full irrigation (I<sub>3</sub>) in subplots. All irrigations were stopped 15 days before sorghum maturity. Full irrigation was 60 mm applied at 50% depletion of available soil water in 1 m profile. Sorghum growth was faster than pigeonpea until 85 days from planting and pigeonpea growth accelerated only after sorghum harvesting. About 80% of sorghum roots were within 0.6 m profile but more than 75% of pigeonpea roots were below 0.60 m depth. This showed a weaker competition between the two crops for nutrients, water and light. Both grain and stover yields of sorghum were optimum in RT + I<sub>2</sub> during the 2 years. Highest grain yield was 6900 kg·ha<sup>-1</sup> in RT + I<sub>3</sub> in 2013, which was at par with that in RT + I<sub>2</sub>. Mean residual soil moisture at sorghum harvesting was 74 mm·m<sup>-1</sup>, which decreased to 8 mm·m<sup>-1</sup> by pigeonpea harvesting. Residual moisture was more in the irrigated than non-irrigated plots. Pigeonpea yields were optimum (1363 kg·ha<sup>-1</sup>) in RT + I<sub>3</sub> and lowest (297 kg·ha<sup>-1</sup>) in ZT + I<sub>0</sub>. Average water use by sorghum-pigeonpea was 374 mm by sorghum harvesting and 438 mm by pigeonpea harvesting, producing total sorghum equivalent yield of 7475 kg·ha<sup>-1</sup>. This raised average water use efficiency from 12.6 kg·ha<sup>-1</sup>·mm<sup>-1</sup> at sorghum harvesting to 17.1 kg·ha<sup>-1</sup>·mm<sup>-1</sup> at pigeonpea harvesting. Benefit was doubled at 50% of full irrigation and >4 times at 75% of full irrigation.
文摘A field experiment was conducted for two consecutive years at North Eastern Indian Himalayan region to assess the effect of soil moisture conservation measures on soil and water productivity of different rainfed maize(Zea mays L.)-based cropping sequences.Results revealed that double mulching with in-situ maize stover mulch(MSM)+fresh biomass of white hoary pea(WHP-Tephrosia candida)and MSM+fresh biomass of ragweed(RW-Ambrosia artemisiifolia)improved soil moisture content(SMC)and leaf relative water content of crops during dry season.The soil organic carbon(SOC)content and stocks under MSM+WHP and MSM+RW mulches were significantly higher than that under no mulch at 0-15 cm depth.The soil microbial biomass carbon and dehydrogenase activity were maximum under MSM+WHP/RW.The highest system productivity was obtained from maize-French bean(Pole type-PT)sequence under MSM+RW followed by MSM+WHP.The water productivity was the highest under MSM+WHP.While SOC content was the highest under maize-French bean(PT),the maximum plant available nitrogen and phosphorus were obtained under maize-black gram sequence.Thus,double mulching technology involving MSM and RW(available in plenty)is a viable option for improving soil,crop and water productivity under rainfed hill ecosystems of eastern Indian Himalayas.
