Search

Proximal sensing is being integrated into vineyard management as it provides rapid assessments of spatial variability of soils' and plants' features. The electromagnetic induction (EMI) technology is used to measure soil apparent electrical conductivity (ECa) with proximal sensing and enables to appraise soil characteristics and their possible effects on plant physiological responses. This study was conducted in a micro irrigated Cabernet Sauvignon (Vitis vinifera L.) vineyard to investigate the technical feasibility of appraising plant water status and its spatial variability using soil ECa and must carbon isotope ratio analysis (δ13C). Soil temperature and soil water content were monitored in-situ using time domain reflectometry (TDR) sensors. Soil ECa was measured with EMI at two depths [0–1.5 m (deep ECa) and 0–0.75 m (shallow ECa)] over the course of the crop season to capture the temporal dynamics and changes. At the study site, the main physical and chemical soil characteristics, i.e. soil texture, gravel, pore water electrical conductivity (ECe), organic carbon, and soil water content at field capacity, were determined from samples collected auguring the soil at equidistant points that were identified using a regular grid. Midday stem water potential (Ψstem) and leaf gas exchange, including stomatal conductance (gs), net carbon assimilation (An), and intrinsic water use efficiency (WUEi) were measured periodically in the vineyard. The δ13C of produced musts was measured at harvest. The results indicated that soil water content (relative importance = 24%) and texture (silt: relative importance = 22.4% and clay: relative importance = 18.2%) were contributing the most towards soil ECa. Deep soil ECa was directly related to Ψstem (r2 = 0.7214) and gs (r2 = 0.5007). Likewise, δ13C of must was directly related to Ψstem (r2 = 0.9127), gs (r2 = 0.6985), and An (r2 = 0.5693). Results from this work provided relevant information on the possibility of using spatial soil ECa sensing and δ13C analysis to infer plant water status and leaf gas exchange in micro irrigated vineyards. [ABSTRACT FROM AUTHOR]

Innovative irrigation practices can enhance water efficiency, gaining an economic advantage while also reducing environmental burdens. In some cases the necessary knowledge has been provided by extension services, helping farmers to adapt and implement viable solutions, thus gaining more benefits from irrigation technology. Often investment in technological improvements has incurred higher water prices, however, without gaining the full potential benefits through water efficiency. Farmers generally lack adequate means and incentives to know crops’ water use, actual irrigation applications, crops’ yield response to different water management practices, and thus current on-farm water-efficiency levels. Those general difficulties are illustrated by our two case studies investigating options, stimuli and difficulties to improve water-efficient practices. The two areas have strong stimuli for improvement but lack a knowledge-exchange system to help farmers and resource managers identify scope for improvements. Partly for this reason, farmers’ responsibility for efficient water management has been displaced to hypothetical prospects, e.g. extra supplies from reuse of treated wastewater or a long-term low water pricing. In both cases a displaced responsibility complements the default assumption that farmers’ irrigation practices already have adequate water-use efficiency. Under current circumstances, agricultural water management will maintain the unknown water-efficiency level and farmers will have weaker incentives to make efforts for more efficient practices. A continuous knowledge-exchange is necessary so that all relevant stakeholders can share greater responsibility across the entire water-supply chain. On this basis, more water-efficient management could combine wider environmental benefits with economic advantage for farmers. [ABSTRACT FROM AUTHOR]

To meet the requirements of California’s Sustainable Groundwater Management Act, there is a critical need for crop production strategies with less reliance on irrigation from surface and groundwater sources. One strategy for improving agricultural water use efficiency is reducing tillage and maintaining residues on the soil surface. We evaluated high residue no-till versus standard tillage in the San Joaquin Valley with and without cover crops on the yields of two crops, garbanzo and sorghum, for 4 years. The no-till treatment had no primary or secondary tillage. Sorghum yields were similar in no-till and standard tillage systems while no-till garbanzo yields matched or exceeded those of standard tillage, depending on the year. Cover crops had no effect on crop yields. Soil cover was highest under the no-till with cover crop system, averaging 97% versus 5% for the standard tillage without cover crop system. Our results suggest that garbanzos and sorghum can be grown under no-till practices in the San Joaquin Valley without loss of yield. [ABSTRACT FROM AUTHOR]