Bill Bellotti

Analysis of gas exchange, stomatal behaviour and micronutrients uncovers dynamic response and adaptation of tomato plants to monochromatic light treatments.

Light spectrum affects the yield and quality of greenhouse tomato, especially over a prolonged period of monochromatic light treatments. Physiological and chemical analysis was employed to investigate the influence of light spectral (blue, green and red) changes on growth, photosynthesis, stomatal behaviour, leaf pigment, and micronutrient levels. We found that plants are less affected under blue light treatment, which was evident by the maintenance of higher A, gs, Tr, and stomatal parameters and significantly lower VPD and Tleaf as compared to those plants grown in green and red light treatments. Green and red light treatments led to significantly larger increase in the accumulation of Fe, B, Zn, and Cu than blue light. Moreover, guard cell length, width, and volume all showed highly significant positive correlations to gs, Tr and negative links to VPD. There was negative impact of monochromatic lights-induced accumulation of Mn, Cu, and Zn on photosynthesis, leaf pigments and plant growth. Furthermore, most of the light-induced significant changes of the physiological traits were partially recovered at the end of experiment. A high degree of morphological and physiological plasticity to blue, green and red light treatments suggested that tomato plants may have developed mechanisms to adapt to the light treatments. Thus, understanding the optimization of light spectrum for photosynthesis and growth is one of the key components for greenhouse tomato production.

Conservation Agriculture in Rainfed Areas of China

Conservation agriculture (CA) is now widely recognized as a viable concept for practicing sustainable agriculture. Grouped under the title “conservation agriculture,” an inter-related and synergetic set of principles and practices have been developed to combat land degradation, falling soil fertility, rapidly declining production levels, inefficient use of scarce water resources, and desertification. China is an ancient agricultural country, its agriculture dates back at least 8000–9000 years. It has a long history of practices of soil and water conservation. Presently—due to a wide range of soil types and climate, and the cropping systems practiced in China—diverse CA systems exist in different agroecological regions of China. However, modern conservation tillage (CT) is fairly new. The total area under CT in China exceeded 6.67 million ha in 2012 with a ten-fold increase in past 10 years. A 13-year case study on the Loess Plateau showed that no-till with stubble retention (NTS) improved grain yield significantly. With NTS, water stored in surface layers is more available for crops than that in deeper layers; surface (0–10 cm) soil water content under NTS improved up to 90 % when compared with conventional tillage. Soil organic carbon improved. Crops under NTS had better growth and yield. Soil quality, water use efficiency, and nitrogen use efficiency improved, and soil erosion significantly decreased. Profitability improved under NTS within two rotation cycles of spring wheat–field pea; total profitability of NTS was 81, 38, 75, 165, and 66 % higher than that of conventional tillage (T), no-till without stubble retention (NT), conventional tillage with stubble incorporated (TS), conventional tillage with plastic mulch (TP), and no-till with plastic mulch (NTP). Therefore, NTS is the best CA practice for improving crop productivity and sustainability. Although the importance of CA has been increasingly recognized, there are many barriers to its widespread adoption including traditional intensive agriculture attitude, small farm sizes, lack of suitable machines, lack of diverse CA technologies, and the high opportunity cost of straw/residues. Therefore, further investment into technical research, machine design, demonstration and extension, and substitutes for fuel and forage are important for a breakthrough on CA adoption in China.

Structural change and agricultural diversification since China’s reforms

Structural change is considered the major engine in fostering a country’s growth. In the agricultural sector, diversification is the commonly used development strategy to increase rural sector’s flexibility, and to respond to improving technologies and market conditions. This study examined agricultural development and transformation during China’s socio-economic reforms. In particular, it empirically investigated whether the change of China’s agricultural structure is consistent with structural change theory and observed outcomes from other countries. The degree of agricultural diversification was quantitatively measured at a regional scale using the Herfindahl index. An underdeveloped province in northwest China was studied to provide insights into the interaction among structural change, agricultural diversification, and implemented development policies. Aggregate-level analyses suggest that China’s agricultural transformation pattern is consistent with those of other developing countries. A specific provincial-level analysis shows that environmentally and economically disadvantaged regions are slower to diversify their economy than better endorsed regions.