No increase of soil wind erosion with the establishment of center pivot irrigation system in Mu-Us sandy land.

Center Pivot Irrigation system (CPIs) is widely used in newly exploited arable land in sandy lands. These sandy lands are currently stable because of climate change and ecological restoration efforts since the beginning of the 21st century in northern China. The exploitation of these fixed sandy lands to arable land with CPIs may affect the soil wind erosion, yet it remains unknown. The temporal changes of CPIs and its effect on wind erosion module were analyzed and modeled from 2000 to 2020 in Mu-Us sandy land using satellite images and Revised Wind Erosion Equation (RWEQ). The establishment of CPIs started from 2010, boomed in 2015 and peaked in 2020. They were mainly transformed from woodland, grassland, and barren land near rivers in east and southeast, and from cropland in inter-dunes in west and southwest of Mu-Us sandy land. The temporal and spatial pattern of CPIs well aligns with the land consolidation and requisition-compensation balance policies. In most of the Mu-Us sandy land, the annual erosion module is <25 t ha-1 a-1. Despite great variation, the annual, Winter and Spring erosion module of the Mu-Us sandy land or in Otog Qian and Yuyang, the CPIs concentrated counties, all decreased during 2000-2019. Although, wind erosion module in CPIs was lower than the surrounding area, it increased in 2019 given the same climate conditions as in 2010. Our results suggest 1) the establishment of CPIs in Mu-Us sandy land greatly depends on the local policy and natural endowment, and 2) although the set-up of CPIs showed no impact on the wind erosion with CPIs accounting for <1 % of Mu-Us sandy land, post-harvest of CPIs should be carefully concerned to prevent soil wind erosion.

The water footprint of irrigation-supplemented cotton and mung-bean crops in Northern Ethiopia.

Global freshwater resources are getting scarcer and scarcer due to the ever-increasing population, climate change, and other human activities. Hence, assessing the consumption of freshwater by different consumers is a key to efficiently utilize the resource. In this study, the Water Footprint Assessment (WFA) tool was used to determine the water footprint (WF) of Center Pivot (CP) irrigated cotton and mung-bean production using two approaches, namely, CROPWAT and field-data based methods. Based on the CROPWAT-based estimates, the average total WF of cotton was found to be 2745 m3/ton. Out of this, the green and blue WF contributed to an average of 35% and 65 %, respectively. For mung-bean, the total WF was 6561m3/ton, of which blue WF covered around 93 %. Comparison of the blue WF from CROPWAT and field-data based estimates showed a good agreement (nRMSE = 4.5 %, nMBE = 10.7 % and relative error/RE/ranging from 0.8 to 17% for cotton and 12.6% for mung-bean) and no significant difference (p = 0.456) was obtained between the two estimates. The effect of planting date on the WF estimation also showed a small variation of 0.7%-6.6 % for cotton and up to 12% for mung-bean. However, major reductions were obtained on the blue WF of cotton and mung-bean as a result of changing planting dates by about two months prior to the baseline planting dates. In this study, it is concluded that WF assessment could be satisfactorily estimated using CROPWAT model if supported with field obtained information such as soil, crop, and weather data. Another finding of the present study was that, changing planting dates close to the major rainy months could substantially contribute to reducing the blue WF in similar climates.

Effects of center pivot sprinkler fertigation on the yield of continuously cropped soybean.

Continuous cropping is a common agricultural practice in Northeast China. Focusing on soybeans cropped continuously for two consecutive years, this article fully explores the effects of the amount of water, fertilizing rate, and fertilizing method on the growth and yield of soybean. Specifically, an orthogonal experimental plan was designed involving these three factors. Each factor was divided into three levels: the amount of water was set as 52.62 mm (W1), 73.41 mm (W2), and 138.6 mm (W3); the fertilizing rate was set as 6.75 kg/hm2 (N1), 9.75 kg/hm2 (N2), and 13.5 kg/hm2 (N3); and the fertilizing method was set as center pivot sprinkler (CPS) fertigation (F1), microspray (MS) fertigation (F2), and MS fertilizing + CPS spraying and leaching (F3). During the experiments, the growth traits at each growth stage were monitored, and the soybean yield was measured. The following results were obtained through the analysis of the experimental data: the amount of water significantly affects the growth traits of soybean in the early stage of growth; the fertilizing rate greatly affects the stem diameter; and the fertilizing method is a major influencer of soybean yield. The highest yield (2811.88 kg/hm2) was observed in zone 4 (W2N1F2). This means irrigation and fertilization are very important to the normal growth of continuously cropped soybean; the yield loss induced by continuous cropping can be mitigated effectively through timely and adequate irrigation and topdressing, plus fertilization by the suitable method. To prevent yield loss, farmers in Northeast China are suggested to replace continuous cropping with crop rotation. If continuous cropping is unavoidable, foliage fertilizer should be sprayed timely for topdressing at the flowering and seed-filling stages.

Energy balance of irrigated maize silage / Balanço energético da cultura do milho para silagem com irrigação

ABSTRACT: The aim of the present study is to evaluate the energy balance and energy efficiency of the silage maize crop in the Center for Research, Development and Technology Transfer of the Universidade Federal de Lavras (CDTT-UFLA). The crop was irrigated by center pivot and the stages of maize cultivation and energy inputs were monitored for the 1st and 2nd crops of the 2014/2015 harvest. Results from the energy analysis showed the crop had a total energy input of 45,643.85 MJ ha-1 and 47,303.60 MJ ha-1 for the 1st and 2nd crops and a significant predominance of direct energy type (about 92% of the matrix). Regarding direct energy inputs, the diesel oil was the most representative, contributing with approximately 38% of the total energy demand. Conversely, the irrigation system contribute with 3.92% e 5.97% in the 1st and 2nd crops, representing the largest indirect energy input. Nevertheless, irrigation and crop management allowed the system achieving high levels of productivity, resulting in an energy efficiency of 25.1 and 28.1 for the first and second crops respectively.

RESUMO: Este trabalho tem como objetivo avaliar o balanço energético e a eficiência energética da cultura milho para silagem implantada no Centro de Desenvolvimento e Transferência de Tecnologia da Universidade Federal de Lavras (CDTT-UFLA). A cultura foi irrigada por pivô central sendo que as etapas de cultivo do milho e entradas de energia foram acompanhadas para 1ª e 2ª safras do ano agrícola de 2014/2015. Os resultados da análise energética mostraram que a cultura teve uma entrada total de energia de 45.643,85MJ ha-1 e 47.303,60MJ ha-1 para a 1ª e 2ª safra, com uma predominância significativa de energia do tipo direta (cerca de 92% da matriz). O óleo diesel foi a fonte de energia direta que mais impactou na matriz, com uma participação de aproximadamente 38%. Já a irrigação teve uma participação de 3,92% e 5,97% na 1ª e 2ª safra respectivamente, representando a maior fonte de energia indireta. Apesar disso, a irrigação e o manejo da cultura permitiram que o sistema alcançasse altos níveis de produtividade, resultando em uma eficiência energética de 25,1 e 28,1 para a 1ª e 2ª safra.